WorldWideScience

Sample records for axis radiographic hydrodynamic

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    Haagenstad, T.

    1999-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Science.gov (United States)

    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. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Inductive voltage adder advanced hydrodynamic radiographic technology demonstration

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  9. AxisSPH:devising and validating an axisymmetric smoothed particle hydrodynamics code

    OpenAIRE

    Relaño Castillo, Antonio

    2012-01-01

    A two-dimensional axisymmetric implementation of the smoothed particle hydrodynamics (SPH) technique, called for short AxisSPH, has been described in this thesis, along with a number of basic tests and realistic applications. The main goal of this work was to fill a gap on a topic which has been scarcely addressed in the published literature concerning SPH. Although the application of AxisSPH to the simulation of real problems is restricted to those systems which display the appropriate ...

  10. Final focusing system for the second axis of the dual-axis radiographic hydrodynamic test facility

    International Nuclear Information System (INIS)

    Chen, Y.-J.; McCarrick, James F.; Paul, Arthur C.; Westenskow, Glen A.

    2002-01-01

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

  11. Validation of a new radiographic measurement of acetabular version: the transverse axis distance (TAD)

    Energy Technology Data Exchange (ETDEWEB)

    Nitschke, Ashley [University of Colorado School of Medicine, University of Colorado Denver, Division of Musculoskeletal Radiology, Department of Radiology, Aurora, CO (United States); Lambert, Jeffery R. [University of Colorado, Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO (United States); Glueck, Deborah H. [University of Colorado, Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO (United States); University of Colorado School of Medicine, University of Colorado Denver, Department of Radiology, Aurora, CO (United States); Jesse, Mary Kristen; Strickland, Colin [University of Colorado School of Medicine, University of Colorado Denver, Division of Musculoskeletal Radiology, Department of Radiology and Orthopaedics, Aurora, CO (United States); Mei-Dan, Omer [University of Colorado School of Medicine, University of Colorado Denver, Division of Sports Medicine and Hip Preservation, Department of Orthopaedics, Aurora, CO (United States); Petersen, Brian [University of Colorado School of Medicine, University of Colorado Denver, Division of Musculoskeletal Radiology, Department of Radiology and Orthopaedics, Aurora, CO (United States); Inland Imaging, Division of Musculoskeletal Radiology, Spokane, WA (United States)

    2015-11-15

    This study has three aims: (1) validate a new radiographic measure of acetabular version, the transverse axis distance (TAD) by showing equivalent TAD accuracy in predicting CT equatorial acetabular version when compared to a previously validated, but more cumbersome, radiographic measure, the p/a ratio; (2) establish predictive equations of CT acetabular version from TAD; (3) calculate a sensitive and specific cut point for predicting excessive CT acetabular anteversion using TAD. A 14-month retrospective review was performed of patients who had undergone a dedicated MSK CT pelvis study and who also had a technically adequate AP pelvis radiograph. Two trained observers measured the radiographic p/a ratio, TAD, and CT acetabular equatorial version for 110 hips on a PACS workstation. Mixed model analysis was used to find prediction equations, and ROC analysis was used to evaluate the diagnostic accuracy of p/a ratio and TAD. CT equatorial acetabular version can accurately be predicted from either p/a ratio (p < 0.001) or TAD (p < 0.001). The diagnostic accuracies of p/a ratio and TAD are comparable (p =0.46). Patients whose TAD is higher than 17 mm may have excessive acetabular anteversion. For that cutpoint, the sensitivity of TAD is 0.73, with specificity of 0.82. TAD is an accurate radiographic predictor of CT acetabular anteversion and provides an easy-to-use and intuitive point-of-care assessment of acetabular version in patients with hip pain. (orig.)

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

    Science.gov (United States)

    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.

  13. Hydrodynamic Performance Analysis on Different Airfoils of Straight Blade H Type of Vertical Axis Tidal Current Energy Turbine

    Directory of Open Access Journals (Sweden)

    Kan Kan

    2016-01-01

    Full Text Available Airfoil is a key factor that influences the hydrodynamic performance of vertical axis tidal current energy turbine. In order to explore the influences from the runner’s blade airfoil towards its hydrodynamic performance, three-dimensional unsteady flow numerical simulation on four airfoils of straight blade H type of tidal current energy turbines was carried out, under the precondition of same turbine compactness. Through investigating the influences from the four different airfoils of H blade towards the runner in terms of its dynamic torque feature and hydropower utilization coefficient, this research has analyzed the hydrodynamic performance of the tidal current energy turbine. As the research result indicates, the maximum dynamic torque value of the single-blade turbine with NACA0015 airfoil is significantly higher than that of the other three airfoils; while the maximum value of the overall runner torque is determined by the operating conditions such as different stream speed etc. As a whole, hydropower utilization coefficient of the turbine with asymmetric airfoil NACA4415 is better than that of the other three airfoils. This research has provided references for the design and airfoil selection for the new type of tidal current energy turbine.

  14. Dynamic Analysis of a Floating Vertical Axis Wind Turbine Under Emergency Shutdown Using Hydrodynamic Brake

    DEFF Research Database (Denmark)

    Wang, K.; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    Emergency shutdown is always a challenge for an operating vertical axis wind turbine. A 5-MW vertical axis wind turbine with a Darrieus rotor mounted on a semi-submersible support structure was examined in this study. Coupled non-linear aero-hydro-servo-elastic simulations of the floating vertical...... axis wind turbine were carried out for emergency shutdown cases over a range of environmental conditions based on correlated wind and wave data. When generator failure happens, a brake should be applied to stop the acceleration of the rotor to prevent the rotor from overspeeding and subsequent disaster...

  15. The interleukin-20 receptor axis in early rheumatoid arthritis: novel links between disease-associated autoantibodies and radiographic progression.

    Science.gov (United States)

    Kragstrup, Tue Wenzel; Greisen, Stinne Ravn; Nielsen, Morten Aagaard; Rhodes, Christopher; Stengaard-Pedersen, Kristian; Hetland, Merete Lund; Hørslev-Petersen, Kim; Junker, Peter; Østergaard, Mikkel; Hvid, Malene; Vorup-Jensen, Thomas; Robinson, William H; Sokolove, Jeremy; Deleuran, Bent

    2016-03-11

    months (Spearman's rho = 0.19 and 0.26, both P < 0.05) in the early RA patients. The IL-22R1 was expressed by osteoclast precursors and in multinucleated osteoclasts. IL-20 and IL-24 increased the secretion of monocyte chemoattractant protein 1 by these cells. This study suggests that IL-20 and IL-24 link RA-associated autoantibodies with radiographic progression via the IL-22R1. Modulation of this axis holds promise as feasible anti-erosive treatment modalities in seropositive RA.

  16. X-ray radiographic imaging of hydrodynamic phenomena in radiation driven materials -- shock propagation, material compression and shear flow

    International Nuclear Information System (INIS)

    Hammel, B.A.; Kilkenny, J.D.; Munro, D.; Remington, B.A.; Kornblum, H.N.; Perry, T.S.; Phillion, D.W.; Wallace, R.J.

    1994-01-01

    One- and two-dimensional, time resolved x-ray radiographic imaging at high photon energy (5-7 keV) is used to study shock propagation, material motion and compression, and the effects of shear flow in solid density samples which are driven by x-ray ablation with the Nova laser. By backlighting the samples with x-rays and observing the increase in sample areal density due to shock compression, the authors directly measure the trajectory of strong shocks (∼40 Mbar) in flight, in solid density plastic samples. Doping a section of the samples with high-Z material (Br) provides radiographic contrast, allowing the measurement of the shock induced particle motion. Instability growth due to shear flow at an interface is investigated by imbedding a metal wire in a cylindrical plastic sample and launching a shock in the axial direction. Time resolved radiographic measurements are made with either a slit-imager coupled to an x-ray streak camera or a pinhole camera coupled to a gated microchannel plate detector, providing ∼ 10-μm spatial and ∼ 100-ps temporal resolution

  17. X-ray radiographic imaging of hydrodynamic phenomena in radiation driven materials -- shock propagation and shear flow

    International Nuclear Information System (INIS)

    Hammel, B.A.; Kilkenny, J.D.; Munro, D.; Remington, B.A.; Wallace, R.J.

    1993-01-01

    One and two dimensional, time resolved x-ray radiographic imaging at high photon energy (5--7 keV) are used to study shock propagation and the effects of shear flow in solid density samples which are driven by x-ray ablation with the Nova laser. By backlighting the samples with x-rays and observing the increase in sample areal density due to shock compression, we directly measure the trajectory of strong shocks (∼ 40 Mbar) in flight, in solid density plastic samples. Doping a section of the planar samples with high-Z material (Br) provides radiographic contrast, allowing a measurement of the shock induced motion of the doped material. Instability growth due to shear flow at an interface is investigated by imbedding a metal wire in a plastic sample parallel to the direction of material motion. Time resolved radiographic measurements are made with either a slit-imager coupled to an x-ray streak camera or a pinhole camera coupled to a gated microchannel plate detector, providing ∼10 μm spatial and ∼100 ps temporal resolution

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

    Science.gov (United States)

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

    2010-11-01

    Radiography is frequently used to investigate otitis media and dental disease in rabbits, although there are few detailed reports regarding the radiographic anatomy of the rabbit skull. The aim of this study was to document rabbit skull radiographic anatomy, with particular reference to the tympanic bulla (TB) and temporomandibular joint (TMJ), and to identify views that allowed optimal assessment of these areas. Equipment was used that allowed repeatable positioning of skulls at known rotational angles in lateral (lateral to rostrocaudal) and long axis (lateral to ventrodorsal) directions. The views were repeated with lead markers attached to anatomical features and cadaver heads. The TB could be best examined between 30° and 60° in both planes. The TMJ was best visualised between 70° and 90° in a lateral direction, particularly along a true rostrocaudal plane, but could not be imaged well at any of the long axis rotational angles. Similar images were obtained using cadavers. Copyright © 2009 Elsevier Ltd. All rights reserved.

  19. The interleukin-20 receptor axis in early rheumatoid arthritis: novel links between disease-associated autoantibodies and radiographic progression

    DEFF Research Database (Denmark)

    Kragstrup, Tue Wenzel; Greisen, Stinne Ravn; Nielsen, Morten Aagaard

    2016-01-01

    , and IL-24 and their shared receptors activates tissue homeostasis processes but not the immune system. Consequently, modulation of the IL-20R axis may not lead to immunosuppression, making it an interesting drug target. We evaluated the role of the IL-20R axis in RA and associations between plasma......BACKGROUND: Rheumatoid arthritis (RA) is often characterized by the presence of rheumatoid factor, anti-citrullinated protein antibodies, and bone erosions. Current therapies can compromise immunity, leading to risk of infection. The interleukin-20 receptor (IL-20R) axis comprising IL-19, IL-20...... from a different cohort of RA patients were evaluated by flow cytometry and confocal microscopy. Monocytes/macrophages were stimulated with heat-aggregated human immunoglobulin immune complexes and immune complexes containing citrullinated fibrinogen, and osteoclasts were incubated with IL-19, IL-20...

  20. Upright MRI measurement of mechanical axis and frontal plane alignment as a new technique: a comparative study with weight bearing full length radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Liodakis, Emmanouil; Kenawey, Mohamed; Doxastaki, Iosifina; Krettek, Christian; Haasper, Carl; Hankemeier, Stefan [Medical School Hannover, Department of Trauma Surgery, Hannover (Germany)

    2011-07-15

    The purpose of this prospective study was to investigate the practicality, accuracy, and reliability of upright MR imaging as a new radiation-free technique for the measurement of mechanical axis. We used upright MRI in 15 consecutive patients (30 limbs, 44.7 {+-} 20.6 years old) to measure mechanical axis deviation (MAD), hip-knee-ankle (HKA) angle, leg length, and all remaining angles of the frontal plane alignment according to Paley (mLPFA, mLDTA, mMPTA, mLDTA, JLCA). The measurements were compared to weight bearing full length radiographs, which are considered to be the standard of reference for planning corrective surgery. FDA-approved medical planning software (MediCAD) was used for the above measurements. Intra- and inter-observer reproducibility using mean absolute differences was also calculated for both methods. The correlation coefficient between angles determined with upright MRI and weight bearing full length radiographs was high for mLPFA, mLDTA, mMPTA, mLDTA, and the HKA angle (r > 0.70). Mean interobserver and intraobserver agreements for upright MRI were also very high (r > 0.89). The leg length and the MAD were significantly underestimated by MRI (-3.2 {+-} 2.2 cm, p < 0.001 and -6.2 {+-} 4.4 mm, p = 0.006, respectively). With the exception of underestimation of leg length and MAD, upright MR imaging measurements of the frontal plane angles are precise and produce reliable, reproducible results. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Radiographic evaluations

    International Nuclear Information System (INIS)

    Williams, J.L.

    1988-01-01

    The author describes how to: perform a systematic evaluation of a chest radiograph; state the classic radiographic description of hyaline membrane disease; list the conditions that cause hyperaeration and describe the radiologic feature of hyperaeration; describe the radiograph of a patient with a congenital diaphragmatic hernia; identify optimum placement of an endotracheal tube, gastric feeding tube, and umbilical artery catheter on a radiograph; differentiate between pulmonary interstitial air and hyaline membrane disease; select radiographic features that would indicate the presence of a tension pneumothorax; describe a lateral decubitus projection and state the type of problem it is most often used to identify; explain the procedure used in obtaining a lateral neck radiograph and list two problems that may require this view; and describe the radiograph of a patient with cystic fibrosis

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    R. Paul Drake

    2007-01-01

    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

  5. Radiographic testing

    International Nuclear Information System (INIS)

    Kuster, J.

    1978-01-01

    In view of great differencies in X-ray transmission it is more difficult to get optimum radiographs of plastics and especially of reinforced plastics than for example of metals. A procedure will be reported how to get with little effort optimum radiographs especially also in the range of long wave-length radiation corresponding 10 to 25 kV.P. (orig.) [de

  6. Radiographic Test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.J; Yang, S.H. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    This report contains theory, procedure technique and interpretation of radiographic examination and written for whom preparing radiographic test Level II. To determine this baseline of technical competence in the examination, the individual must demonstrate a knowledge of radiography physics, radiation safety, technique development, radiation detection and measurement, facility design, and the characteristics of radiation-producing devices and their principles of operation. (author) 98 figs., 23 tabs.

  7. Radiographic positioning

    International Nuclear Information System (INIS)

    Eisenberg, R.L.; Dennis, C.A.; May, C.

    1989-01-01

    This book concentrates on the routine radiographic examinations commonly performed. It details the wide variety of examinations possible and their place in initial learning and in the radiology department as references for those occasions when an unusual examination is requested. This book provides information ranging from basic terminology to skeletal positioning to special procedures. Positions are discussed and supplemented with a picture of a patient, the resulting radiograph, and a labeled diagram. Immobilization and proper shielding of the patient are also shown

  8. Relativistic hydrodynamics

    CERN Document Server

    Luciano, Rezzolla

    2013-01-01

    Relativistic hydrodynamics is a very successful theoretical framework to describe the dynamics of matter from scales as small as those of colliding elementary particles, up to the largest scales in the universe. This book provides an up-to-date, lively, and approachable introduction to the mathematical formalism, numerical techniques, and applications of relativistic hydrodynamics. The topic is typically covered either by very formal or by very phenomenological books, but is instead presented here in a form that will be appreciated both by students and researchers in the field. The topics covered in the book are the results of work carried out over the last 40 years, which can be found in rather technical research articles with dissimilar notations and styles. The book is not just a collection of scattered information, but a well-organized description of relativistic hydrodynamics, from the basic principles of statistical kinetic theory, down to the technical aspects of numerical methods devised for the solut...

  9. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  10. Hydrodynamic Lubrication

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 9. Hydrodynamic Lubrication Experiment with 'Floating' Drops. Jaywant H Arakeri K R Sreenivas. General Article Volume 1 Issue 9 September 1996 pp 51-58. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. Hydrodynamic disperser

    Energy Technology Data Exchange (ETDEWEB)

    Bulatov, A.I.; Chernov, V.S.; Prokopov, L.I.; Proselkov, Yu.M.; Tikhonov, Yu.P.

    1980-01-15

    A hydrodynamic disperser is suggested which contains a housing, slit nozzles installed on a circular base arranged opposite from each other, resonators secured opposite the nozzle and outlet sleeve. In order to improve the effectiveness of dispersion by throttling the flow, each resonator is made in the form of a crimped plate with crimpings that decrease in height in a direction towards the nozzle.

  12. Theoretical hydrodynamics

    CERN Document Server

    Milne-Thomson, L M

    2011-01-01

    This classic exposition of the mathematical theory of fluid motion is applicable to both hydrodynamics and aerodynamics. Based on vector methods and notation with their natural consequence in two dimensions - the complex variable - it offers more than 600 exercises and nearly 400 diagrams. Prerequisites include a knowledge of elementary calculus. 1968 edition.

  13. Recent development of hydrodynamic modeling

    Science.gov (United States)

    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

  14. Report on the behalf of the Foreign Affairs, Defence and Armed Forces Commission on the bill project authorizing the ratification of the treaty between the French Republic, the United-Kingdom of Great-Britain and Northern Ireland related to common hydrodynamic and radiographic installations

    International Nuclear Information System (INIS)

    Pintat, X.

    2011-01-01

    After a presentation of the main directions defined during the London summit for the French-British defence cooperation (convergence of interests and ambitions, cooperation in the operational, capacity, technological and industrial areas), this report more precisely presents and discusses the cooperation perspectives in the military nuclear field (deterrence by the French and British nuclear weapons, the experimentation as a field of cooperation, cooperation modalities with a common installation and a common technological development centre). These perspectives encompass experimentation installations aimed at the simulation of nuclear weapons. Then, it details the content of the treaty related to common hydrodynamic and radiographic installations: characteristics of the EPURE and TDC installations, financing conditions, and some other issues

  15. Nanoflow hydrodynamics

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; Dyre, Jeppe C.; Daivis, Peter J.

    2011-01-01

    We show by nonequilibrium molecular dynamics simulations that the Navier-Stokes equation does not correctly describe water flow in a nanoscale geometry. It is argued that this failure reflects the fact that the coupling between the intrinsic rotational and translational degrees of freedom becomes...... important for nanoflows. The coupling is correctly accounted for by the extended Navier-Stokes equations that include the intrinsic angular momentum as an independent hydrodynamic degree of freedom. © 2011 American Physical Society....

  16. Radiographers and trainee radiologists reporting accident radiographs

    DEFF Research Database (Denmark)

    Buskov, L; Abild, A; Christensen, A

    2013-01-01

    To compare the diagnostic accuracy and clinical validity of reporting radiographers with that of trainee radiologists whom they have recently joined in reporting emergency room radiographs at Bispebjerg University Hospital.......To compare the diagnostic accuracy and clinical validity of reporting radiographers with that of trainee radiologists whom they have recently joined in reporting emergency room radiographs at Bispebjerg University Hospital....

  17. Radiographic element

    International Nuclear Information System (INIS)

    Abbott, T.I.; Jones, C.G.

    1983-01-01

    Radiographic elements are disclosed having first and second silver halide emulsion layers comprised of a dispersing medium and radiation-sensitive silver halide grains, and a support interposed between said silver halide emulsion layers capable of transmitting radiation to which said second silver halide emulsion layer is responsive. These elements are characterized in that at least said first silver halide emulsion layer contains tabular silver halide grains and spectral sensitizing dye adsorbed to the surface of the grains. Crossover can be improved in relation to the imaging characteristics. (author)

  18. Radiographic tales

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder

    Purpose Until now a large number of scientific studies have focused on technological aspects of radiography. This study is a step in another direction which examines the relationship between man and technology within radiography instead of considering man and technology as separate entities. Meth...... of their narrative alertness. Errors and failure to keep the time schedule can, however, lead the radiographers to a change of perspective that makes them displace man from the scene of radiography by playing on the premises of technology........ Methods The study is designed as an observational study with a narrative approach. The participant observations took place in a Danish radiological department and involved 20 examinations followed up by three semi-structured interviews. Conclusions Through emergent narratives radiographers construct...... and symptoms. The plot is organized in a relatively concrete and fairly limited space of possibilities, i.e. the number of different diagnoses that can be made. In opposition to the diagnostic plot stands the lifestory as a masterplot. In the lifestory the examination is plotted as a significant experience...

  19. Supernova hydrodynamics

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1981-01-01

    The explosion of a star 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 should be thought to be an old accreting white dwarf, 1.4 M/sub theta/, with a close companion star. A type II SN is thought to be a massive young star 6 to 10 M/sub theta/. The mechanism of explosion is still a challenge to our ability to model the most extreme conditions of matter and hydrodynamics that occur presently and excessively in the universe. 39 references

  20. Submarine hydrodynamics

    CERN Document Server

    Renilson, Martin

    2015-01-01

    This book adopts a practical approach and presents recent research together with applications in real submarine design and operation. Topics covered include hydrostatics, manoeuvring, resistance and propulsion of submarines. The author briefly reviews basic concepts in ship hydrodynamics and goes on to show how they are applied to submarines, including a look at the use of physical model experiments. The issues associated with manoeuvring in both the horizontal and vertical planes are explained, and readers will discover suggested criteria for stability, along with rudder and hydroplane effectiveness. The book includes a section on appendage design which includes information on sail design, different arrangements of bow planes and alternative stern configurations. Other themes explored in this book include hydro-acoustic performance, the components of resistance and the effect of hull shape. Readers will value the author’s applied experience as well as the empirical expressions that are presented for use a...

  1. Radiographic apparatus

    International Nuclear Information System (INIS)

    Lapidus, S.N.

    1979-01-01

    Raytheon Company, U.S.A. have patented an on-line electronic system of normalising the responses from the photomultiplier tubes used in conjunction with a scintillator in an X-ray radiographic camera. A problem with present cameras is that the individual photomultipliers have different intensity responses which also change in time with respect to each other. The individual responses of each photomultiplier tube are measured with a uniform sheet of radioactive material in front of the camera. The associated electronic equipment then calculates scaling factors which give all photomultiplier tubes an identical response and then places these factors in an addressable store. The store is then addressed in an on-line mode to produce a visual display of the transmitted X-rays. (U.K.)

  2. Thermo-hydrodynamic lubrication in hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the thermo-hydrodynamic and the thermo-elasto-hydrodynamic lubrication. The algorithms are methodically detailed and each section is thoroughly illustrated.

  3. Does measurement of the anatomic axis consistently predict hip-knee-ankle angle (HKA) for knee alignment studies in osteoarthritis? Analysis of long limb radiographs from the multicenter osteoarthritis (MOST) study.

    Science.gov (United States)

    Sheehy, L; Felson, D; Zhang, Y; Niu, J; Lam, Y-M; Segal, N; Lynch, J; Cooke, T D V

    2011-01-01

    Researchers commonly use the femoral shaft-tibial shaft angle (FS-TS) from knee radiographs to estimate the hip-knee-ankle angle (HKA) in studies examining risk factors for knee osteoarthritis (OA) incidence and progression. The objective of this study was to determine the relationship between HKA and FS-TS, depending on the method of calculating FS-TS and the direction and degree of knee deformity. 120 full-length digital radiographs were assigned, with 30 in each of four alignment groups (0.0°-4.9°, and ≥5.0° of varus and valgus), from a large cohort of persons with and at risk of knee OA. HKA and five measures of FS-TS (using progressively shorter shaft lengths) were obtained using Horizons Analysis Software, Orthopaedic Alignment & Imaging Systems Inc. (OAISYS). The offsets between HKA and the different versions of FS-TS were calculated, with 95% confidence intervals (CIs). Pearson correlations were calculated. In varus limbs use of a shorter shaft length increased the offset between HKA and FS-TS from 5.1° to 7.0°. The opposite occurred with valgus limbs (from 5.0° to 3.7°). Correlations between HKA and FS-TS for the whole sample of 120 individuals were excellent (r range 1.00-0.88). However, correlations for individual alignment groups were low to moderate, especially for the shortest-shaft FS-TS (r range 0.41-0.66). The offsets obtained using the shorter FS-TS measurements vary depending on direction and degree of knee deformity, and therefore may not provide reliable predictions for HKA We recommend that full-length radiographs be used whenever an accurate estimation of HKA is required, although broad categories of alignment can be estimated with FS-TS. Copyright © 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  4. Hydrodynamic dispersion

    International Nuclear Information System (INIS)

    Pryce, M.H.L.

    1985-01-01

    A dominant mechanism contributing to hydrodynamic dispersion in fluid flow through rocks is variation of travel speeds within the channels carrying the fluid, whether these be interstices between grains, in granular rocks, or cracks in fractured crystalline rocks. The complex interconnections of the channels ensure a mixing of those parts of the fluid which travel more slowly and those which travel faster. On a macroscopic scale this can be treated statistically in terms of the distribution of times taken by a particle of fluid to move from one surface of constant hydraulic potential to another, lower, potential. The distributions in the individual channels are such that very long travel times make a very important contribution. Indeed, while the mean travel time is related to distance by a well-defined transport speed, the mean square is effectively infinite. This results in an asymmetrical plume which differs markedly from a gaussian shape. The distribution of microscopic travel times is related to the distribution of apertures in the interstices, or in the microcracks, which in turn are affected in a complex way by the stresses acting on the rock matrix

  5. Effects of rotation radiographic dimensions of metacarpals

    International Nuclear Information System (INIS)

    Armes, F.M.; Horsman, A.; Bentley, H.B.

    1979-01-01

    An experiment is described which shows that small rotations of metacarpals about their long axis produce small systematic changes in the cortical dimensions as measured by radiographic morphometry. The effect is of no significance in cross-sectional studies but is an important source of error in sequential studies. (author)

  6. Radiographic diagnosis of diaphragmatic hernia: review of 60 cases in dogs and cats.

    Science.gov (United States)

    Hyun, Changbaig

    2004-06-01

    Sixty cases of diaphragmatic hernia in dogs and cats were radiologically reviewed and categorized by their characteristic radiographic signs. Any particular predilection for age, sex, or breed was not observed. Liver, stomach and small intestine were more commonly herniated. At least two radiographs, at different angles, were required for a valid diagnosis, because some radiographic signs were not visible in a single radiographic view and more clearly detectable in two radiographic views. In addition to previously reported radiographic signs for diaphragmatic hernia, we found that the location of the stomach axis and the displacement of tracheal and bronchial segments were also useful radiographic signs.

  7. Radiographic femoral varus measurement is affected unpredictably by femoral rotation

    DEFF Research Database (Denmark)

    Miles, James Edward

    Radiographic measurements of femoral varus are used to determine if intervention to correct femoral deformity is required, and to calculate the required correction. The varus angle is defined as the angle between the proximal femoral long axis (PFLA) and an axis tangential to the distal femoral...... condyles. Ideal positioning of the femur in terms of zero elevation relative to the radiographic plane or zero rotation along the long axis of the femur may be difficult to obtain in practice. The clinician may thus be tempted to determine varus values from less than ideal radiographs. Fourteen isolated...... and externally by 5° and 10° using plastic wedges. Accuracy of rotation was within +1°. Digital radiographs were obtained at each position. Varus angles were measured using ImageJ, employing two definitions of PFLA. Mean varus angles increased with 10° of either internal or external rotation with both PFLA...

  8. Axis Spectrometer

    International Nuclear Information System (INIS)

    Park, Sungil

    2006-01-01

    The Cold Neutron Research Facility (CNRF) project carried out by Korea Atomic Energy Research Institute (KAERI) is an effort to bring cold neutron instrumentation to Korea's only large scale research reactor, HANARO, located in Daejeon. As part of the CNRF project, a cold neutron triple-axis spectrometer (Cold-TAS) is being developed along with other five: 40 m long and 12 m long small angle neutron scattering instruments (40m-SANS and 12m-SANS), disk-chopper time-of-flight spectrometer (DC-ToF), Bio- Reflectometer (Bio-REF) and the reflectometer with vertical sample geometry (REF-V). For those cold neutron instruments, the performance of an individual instrument depends not only on its design but also on the guide that feeds cold neutrons to the instrument. Therefore, the quality of the neutron flux at an instrument position has to be checked with the specification of the instrument. As for the Cold-TAS, since the instrument requires a tall beam and a high flux of short wavelength neutrons, it was tentatively decided that it would use the cold guide 4 (CG4). The detailed specification of the guide is listed. Checking the neutron flux of the guide at the instrument position is the obvious next step

  9. Quality of radiograph

    International Nuclear Information System (INIS)

    Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

    2008-01-01

    This chapter discussed on how to get a good radiograph. There are several factors that can make good radiograph such as density of radiograph, the contrast of radiograph, definition of radiograph, the present of artifact and backscattering. All of this factor will discuss detailed on each unit of chapter with some figure, picture to make the reader understand more when read this book. And at the end, the reader will introduce with penetrameter, one of device to determine the level of quality of the radiograph. There are two type of penetrameter like wire type or holes type. This standard must be followed by all the radiographer around the world to produce the good result that is standard and more reliable.

  10. Functional radiographs of the craniocervical region and cervical spine

    International Nuclear Information System (INIS)

    Mayer, E.T.; Auberger, T.; Herrmann, G.; Pfaffenrath, W.; Poellmann, W.

    1985-01-01

    Disabilities of the articulation of the head and cervical spine can often be detected only by exact measurement of functional radiographs. From two radiographs, one in flexion and one in extension, not only can the total mobility of the head be measured, but also the mobility of the individual articulations can be evaluated by taking exact measurements of the position of each vertebra. A method for semi-automatic measuring of such pairs of radiographs is presented. Edges and structures of the bones that are clearly visible in both radiographs are digitized on a graphict tablet. Then, by computer program, each vertebra of the first radiograph is shifted and rotated until it fits best to the respective vertebra of the second radiograph. Thus, for each articulation, the mobility angle and the location of the mobility axis relative to the adjacent vertebra, can be computed. First experiences with this method are presented

  11. Elasto-hydrodynamic lubrication

    CERN Document Server

    Dowson, D; Hopkins, D W

    1977-01-01

    Elasto-Hydrodynamic Lubrication deals with the mechanism of elasto-hydrodynamic lubrication, that is, the lubrication regime in operation over the small areas where machine components are in nominal point or line contact. The lubrication of rigid contacts is discussed, along with the effects of high pressure on the lubricant and bounding solids. The governing equations for the solution of elasto-hydrodynamic problems are presented.Comprised of 13 chapters, this volume begins with an overview of elasto-hydrodynamic lubrication and representation of contacts by cylinders, followed by a discussio

  12. Elementary classical hydrodynamics

    CERN Document Server

    Chirgwin, B H; Langford, W J; Maxwell, E A; Plumpton, C

    1967-01-01

    Elementary Classical Hydrodynamics deals with the fundamental principles of elementary classical hydrodynamics, with emphasis on the mechanics of inviscid fluids. Topics covered by this book include direct use of the equations of hydrodynamics, potential flows, two-dimensional fluid motion, waves in liquids, and compressible flows. Some general theorems such as Bernoulli's equation are also considered. This book is comprised of six chapters and begins by introducing the reader to the fundamental principles of fluid hydrodynamics, with emphasis on ways of studying the motion of a fluid. Basic c

  13. Fast radiographic systems

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1984-08-01

    Industrial radiography can be performed with shorter exposure times, when instead of X-ray film with lead intensifying screens the radiographic paper with fluorescent screen is used. With paper radiography one can obtain lower material, equipment, and labor costs, shorter exposure and processing times, and easier radiation protection. The speed of the radiographic inspection can also be increased by the use of fluorometallic intensifying screens together with a special brand of X-ray film. Before accepting either of the two fast radiographic systems one must be sure that they can produce radiographs of adequate image quality. Therefore an investigation was performed on that subject using ISO wire IQI's and ASTM penetrameters. The radiographic image quality was tested for aluminium and steel up to 30 mm thick using various brands of radiographic paper and X-ray film with fluorometallic screens and comparing them with fast X-ray films with lead screens. Both systems give satisfactory results. (author)

  14. Radiographic constant exposure technique

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1985-01-01

    The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality was tes...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...

  15. Radiographic constant exposure technique

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1985-01-01

    The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...

  16. Visual simulation of radiographs

    International Nuclear Information System (INIS)

    Laguna, G.

    1985-01-01

    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

  17. A comparative assessment of alternatives to the full-leg radiograph for determining knee joint alignment

    Directory of Open Access Journals (Sweden)

    Navali Amir M

    2012-10-01

    Full Text Available Abstract Background The purpose of this study was to assess the concurrent validity of alternative measures of frontal plane knee alignment, namely the radiographic anatomic axis and two clinical measures in patients complaining of knee malalignment as compared with the mechanical axis on full-length radiograph of lower limbs. Methods The knee-alignment angle was measured in 100 knees of 50 subjects with the chief complaint of frontal knee malalignment according to the following methods: lower-limb mechanical axis on radiograph, lower-limb anatomic axis on radiograph, distance between medial femoral condyles or medial malleoli using a calliper and lower-limb alignment using a goniometer. Data were analyzed using Pearson’s correlation coefficient and simple linear regression. Results The anatomic axis best correlated with the mechanical axis (r = 0.93, P Conclusions The anatomic axis on radiograph, the calliper method and to a lesser extent the goniometer measurement appear to be valid alternatives to the mechanical axis on full-leg radiograph for determining frontal plane knee alignment. These alternative measures have the potential to provide useful information regarding knee alignment and may increase the assessment of this parameter by clinicians and researchers.

  18. Soft X-ray spectrometer design for warm dense plasma measurements on DARHT Axis-I

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, Nicholas Bryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perry, John Oliver [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Coleman, Joshua Eugene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-11

    A preliminary design study is being performed on a soft X-ray spectrometer to measure K-shell spectra emitted by a warm dense plasma generated on Axis-I of the Dual-Axis Radiographic Hydrodynamic Testing (DARHT) facility at Los Alamos National Laboratory. The 100-ns-long intense, relativistic electron pulse with a beam current of 1.7 kA and energy of 19.8 MeV deposits energy into a thin metal foil heating it to a warm dense plasma. The collisional ionization of the target by the electron beam produces an anisotropic angular distribution of K-shell radiation and a continuum of both scattered electrons and Bremsstrahlung up to the beam energy of 19.8 MeV. The principal goal of this project is to characterize these angular distributions to determine the optimal location to deploy the soft X-ray spectrometer. In addition, a proof-of-principle design will be presented. The ultimate goal of the spectrometer is to obtain measurements of the plasma temperature and density to benchmark equation-of-state models of the warm dense matter regime.

  19. Legalities of the radiograph

    International Nuclear Information System (INIS)

    Bundy, A.L.

    1988-01-01

    The radiograph itself plays a major role in medical malpractice cases. Also, many questions arise concerning the rights to and storage of x-ray films. These issues are addressed in this chapter. To keep the terminology simple, the word radiograph represents all imaging documentation on hard copy film (x-rays, nuclear medicine, computer-assisted studies, ultrasound, and magnetic resonance imaging)

  20. Applied pathology for radiographers

    International Nuclear Information System (INIS)

    Laudicina, P.

    1987-01-01

    This book presents a basic text for the student of radiologic sciences. It includes most of the pathology recommended by the ASRT Curriculum Guide. Radiographic technique and positioning are examined when relevant to obtaining quality radiographs of specific disease conditions. Brief overviews of these conditions include background etiology, diagnosis, treatment and prognosis. Many illustrations are included to enhance understanding

  1. HYDRODYNAMICS OF OSCILLATING WING ON THE PITCH ANGLE

    Directory of Open Access Journals (Sweden)

    Vitalii Korobov

    2017-07-01

    Full Text Available Purpose: research of the hydrodynamic characteristics of a wing in a nonstationary stream. Methods: The experimental studies of the hydrodynamic load acting on the wing of 1.5 elongation, wich harmonically oscillated respect to the transversal axis in the frequency range of 0.2-2.5 Hz. The flow speed in the hydrodynamic tunnel ranged of 0.2-1.5 m/s. Results: The instantaneous values of the coefficients of lift and drag / thrust on the pitch angle at unsteady flow depends on the Strouhal number.Discussion: with increasing oscillation frequency coefficients of hydrodynamic force components significantly higher than the data for the stationary blowing out of the wing.

  2. Hydrodynamic Vortex on Surfaces

    Science.gov (United States)

    Ragazzo, Clodoaldo Grotta; de Barros Viglioni, Humberto Henrique

    2017-10-01

    The equations of motion for a system of point vortices on an oriented Riemannian surface of finite topological type are presented. The equations are obtained from a Green's function on the surface. The uniqueness of the Green's function is established under hydrodynamic conditions at the surface's boundaries and ends. The hydrodynamic force on a point vortex is computed using a new weak formulation of Euler's equation adapted to the point vortex context. An analogy between the hydrodynamic force on a massive point vortex and the electromagnetic force on a massive electric charge is presented as well as the equations of motion for massive vortices. Any noncompact Riemann surface admits a unique Riemannian metric such that a single vortex in the surface does not move ("Steady Vortex Metric"). Some examples of surfaces with steady vortex metric isometrically embedded in R^3 are presented.

  3. Interpretation of panoramic radiographs.

    Science.gov (United States)

    Perschbacher, Susanne

    2012-03-01

    Panoramic radiography has become a commonly used imaging modality in dental practice and can be a valuable diagnostic tool in the dentist's armamentarium. However, the panoramic image is a complex projection of the jaws with multiple superimpositions and distortions which may be exacerbated by technical errors in image acquisition. Furthermore, the panoramic radiograph depicts numerous anatomic structures outside of the jaws which may create additional interpretation challenges. Successful interpretation of panoramic radiographs begins with an understanding of the normal anatomy of the head and neck and how it is depicted in this image type. This article will describe how osseous structures, soft tissues, air spaces and ghost shadows contribute to the final panoramic image. A systematic and repeated approach to examining panoramic radiographs, which is recommended to ensure that critical findings are not overlooked, is also outlined. Examples of challenging interpretations, including variations of anatomy, artefacts and disease, are presented to illustrate these concepts. © 2012 Australian Dental Association.

  4. Radiographic aspects of xeroradiography

    International Nuclear Information System (INIS)

    Rao, G.U.V.; Fatouros, P.P.

    1980-01-01

    The quality of a conventional radiographic image can be characterized in terms of five basic parameters; density, contrast, latitude, resolution and noise. Since xeroradiographic images exhibit very limited broad area contrasts, and image formation is predominantly due to edge enhancement, a straightforward description of image quality using the same five parameters is not adequate. A detailed study was made of the radiographic aspects of xeroradiography with special reference to mammography, and a summary of major findings to date with appropriate references to published papers is presented

  5. Hydrodynamic Cavitation Reactors contd…

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Hydrodynamic Cavitation Reactors contd… Reservoir: 10 L capacity. Centrifugal Pump :1.5kW). Orifice plate (different configurations in terms of number and diameter of the holes). Bypass line (for controlling the inlet pressure and the flow rate into the cavitation ...

  6. Dissipative relativistic hydrodynamics

    International Nuclear Information System (INIS)

    Imshennik, V.S.; Morozov, Yu.I.

    1989-01-01

    Using the comoving reference frame in the general non-inertial case, the relativistic hydrodynamics equations are derived with an account for dissipative effects in the matter. From the entropy production equation, the exact from for the dissipative tensor components is obtained. As a result, the closed system of equations of dissipative relativistic hydrodynamics is obtained in the comoving reference frame as a relativistic generalization of the known Navier-Stokes equations for Lagrange coordinates. Equations of relativistic hydrodynamics with account for dissipative effects in the matter are derived using the assocoated reference system in general non-inertial case. True form of the dissipative tensor components is obtained from entropy production equation. Closed system of equations for dissipative relativistic hydrodynamics is obtained as a result in the assocoated reference system (ARS) - relativistic generalization of well-known Navier-Stokes equations for Lagrange coordinates. Equation system, obtained in this paper for ARS, may be effectively used in numerical models of explosive processes with 10 51 erg energy releases which are characteristic for flashes of supernovae, if white dwarf type compact target suggested as presupernova

  7. Hydrodynamics and phases of flocks

    International Nuclear Information System (INIS)

    Toner, John; Tu Yuhai; Ramaswamy, Sriram

    2005-01-01

    We review the past decade's theoretical and experimental studies of flocking: the collective, coherent motion of large numbers of self-propelled 'particles' (usually, but not always, living organisms). Like equilibrium condensed matter systems, flocks exhibit distinct 'phases' which can be classified by their symmetries. Indeed, the phases that have been theoretically studied to date each have exactly the same symmetry as some equilibrium phase (e.g., ferromagnets, liquid crystals). This analogy with equilibrium phases of matter continues in that all flocks in the same phase, regardless of their constituents, have the same 'hydrodynamic'-that is, long-length scale and long-time behavior, just as, e.g., all equilibrium fluids are described by the Navier-Stokes equations. Flocks are nonetheless very different from equilibrium systems, due to the intrinsically nonequilibrium self-propulsion of the constituent 'organisms'. This difference between flocks and equilibrium systems is most dramatically manifested in the ability of the simplest phase of a flock, in which all the organisms are, on average moving in the same direction (we call this a 'ferromagnetic' flock; we also use the terms 'vector-ordered' and 'polar-ordered' for this situation) to exist even in two dimensions (i.e., creatures moving on a plane), in defiance of the well-known Mermin-Wagner theorem of equilibrium statistical mechanics, which states that a continuous symmetry (in this case, rotation invariance, or the ability of the flock to fly in any direction) can not be spontaneously broken in a two-dimensional system with only short-ranged interactions. The 'nematic' phase of flocks, in which all the creatures move preferentially, or are simply oriented preferentially, along the same axis, but with equal probability of moving in either direction, also differs dramatically from its equilibrium counterpart (in this case, nematic liquid crystals). Specifically, it shows enormous number fluctuations, which

  8. Nondestructive examination - radiographic techniques

    International Nuclear Information System (INIS)

    Maier, H.J.

    1980-01-01

    First the basic principles of radiography are to be treated, especially the different radiation sources (X-ray, gamma-ray, neutrons, heat). In the second part those radiographic methods are shown, which are in common use for technical purposes, especially under the aspect of flaw recognition. (orig./RW)

  9. Matching hand radiographs

    NARCIS (Netherlands)

    Kauffman, J.A.; Slump, Cornelis H.; Bernelot Moens, H.J.

    2005-01-01

    Biometric verification and identification methods of medical images can be used to find possible inconsistencies in patient records. Such methods may also be useful for forensic research. In this work we present a method for identifying patients by their hand radiographs. We use active appearance

  10. Learner concerns of radiographers

    International Nuclear Information System (INIS)

    Popli, Pawan Kumar

    1998-01-01

    Today radiology is fastest developing branch of medical sciences. Most of the radiographers are trained in old fashion, most of training institutes lack proper equipment. It not only affects their career but radiological quality at large. For this purpose it is necessary to find out educational possibilities and needs of group. Therefore this project was taken up

  11. Computed tomography for radiographers

    International Nuclear Information System (INIS)

    Brooker, M.J.

    1986-01-01

    This book is directed towards giving radiographers an introduction to and basic knowledge of computerized tomography. The technical section discusses gantries and x-ray production, computer and disc drive image display, storage, artefacts quality assurance and design of departments. The clinical section includes patient preparation, radiotherapy planning, and interpretation of images from various areas of the anatomy. (U.K.)

  12. Hydrodynamics of insect spermatozoa

    Science.gov (United States)

    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.

  13. Radiologic Evaluation of the Renal Axis in Patients with an Accessory Renal Artery

    International Nuclear Information System (INIS)

    Choi, Joon Ho; Kim, Hyoung Jung; Lim, Joo Won; Ko, Young Tae; Lee, Eun Ha

    2010-01-01

    The purpose of this study is to evaluate the association between an accessory renal artery (ARA) and the renal axis seen on radiographs. The MDCT axial images of 428 patients were used to detect the presence of an ARA and its location. The plain radiographs were used to measure the renal axis angle, which was the angle between the longitudinal spinal axis and the renal axis. We correlated these results to determine the association between an ARA and the renal axis. Of the 856 kidneys (428 patients), 19 kidneys had an ARA in the upper pole, 63 kidneys had an ARA in the hilum and 20 kidneys had an ARA in the lower pole. The mean renal axis angles of these three groups were 16.7 degrees, 15.9 degrees and 11.2 degrees respectively. The mean renal axis angle without an ARA was 16.8 degrees. The renal axis angles with an ARA in the upper pole or hilum showed no significant differences compared to those without an ARA. However, the renal axis angle with an ARA in the lower pole was significantly smaller than those without an ARA. On plain radiographs, the axis of kidneys with an ARA in the lower pole maybe more vertical than those without an ARA

  14. Osteology for radiographers

    Energy Technology Data Exchange (ETDEWEB)

    Shillingford, C.

    1985-01-01

    Radiographers need a detailed knowledge of the skeleton and it is not easy to find the correct level of information in the textbooks available to date. This book aims to fill this void. Descriptions of individual bones are logical and easy to follow, and common examples of pathology are included for each bone. Self-assessment questions are given at the end of each paper to enable students to assess their acquired knowledge and to facilitate private study.

  15. Pocket atlas of radiographic anatomy

    International Nuclear Information System (INIS)

    Moeller, T.B.; Reif, E.; Stark, P.

    1993-01-01

    The 'Pocket Atlas of Radiographic Anatomy' presents 170 radiographs of the various body regions of adults, showing only the normal radiographic anatomy. Each radiograph is supplemented on the opposite page by a drawing of the particular body region. There is no commenting text, but the drawings are provided with captions in English. The atlas is a useful guide for interpreting radiographs. The pictures are arranged in chapters entitled as follows: Skeletal Imaging (skull, spine, upper extremity), lower extremity; Miscellaneous Plain Films (chest, mammogram, trachea, lung tomograms); Contrast Examinations (gastrointestinal tract, intravenous contrast examinations, arthrography, angiography); Special Examinations (myelograms, lymphangiograms, bronchograms, sialograms). (UWA). 348 figs [de

  16. Radiographic findings in immunodeficiency

    International Nuclear Information System (INIS)

    Obregon, R.; Lynch, D.A.; Cink, T.M.; Newell, J.D.; Kirkpatrick, C.

    1991-01-01

    This paper reviews the chest radiographs and high-resolution CT (HRCT) scans in patients with immunodeficiency disorders and define the role of HRCT. Thirty-three cases were retrospectively graded according to the consensus of two radiologists. Patients with HIV seropositivity and asthma were excluded. HRCT was performed in 12 cases with standard techniques. Diagnoses included common variable hypogammaglobulinemia (n = 19), X-linked agammaglobulinemia (n = 4), chronic mucocutaneous candidiasis (n = 4), and selective immunoglobulin g deficiencies (n = 2). Chest radiographs showed bronchiectasis in 11 of 33 cases with a predominant lower lobe distribution (82%). Nodules were present in six cases and mucus plugs in four cases. HRCT showed bronchiectasis in nine of 12 cases; in five of these nine cases, bronchiectasis was not apparent on chest radiographs. Other HRCT findings included segmental air trapping (four of 12), mucus plugs (three of 12), hazy consolidation (four of 12), nodules (five of 12), and bronchiolectasis (two of 12). Therapy was altered in seven of 12 cases in which HRCT was performed. Most pertinent to clinical management were the presence of a thymoma (n = 1) and severe focal of diffuse bronchiectasis

  17. Radiograph identifying means

    International Nuclear Information System (INIS)

    Sheldon, A.D.

    1983-01-01

    A flexible character-indentable plastics embossing tape is backed by and bonded to a lead strip, not more than 0.025 inches thick, to form a tape suitable for identifying radiographs. The lead strip is itself backed by a relatively thin and flimsy plastics or fabric strip which, when removed, allows the lead plastic tape to be pressure-bonded to the surface to be radiographed. A conventional tape-embossing gun is used to indent the desired characters in succession into the lead-backed tape, without necessarily severing the lead; and then the backing strip is peeled away to expose the layer of adhesive which pressure-bonds the indented tape to the object to be radiographed. X-rays incident on the embossed tape will cause the raised characters to show up dark on the subsequently-developed film, whilst the raised side areas will show up white. Each character will thus stand out on the developed film. (author)

  18. Radiographic testing of wood

    International Nuclear Information System (INIS)

    Osterloh, K.; Zscherpel, U.; Raedel, C.; Weidemann, G.; Meinel, D.; Goebbels, J.; Ewert, U.; Hasenstab, A.; Buecherl, T.

    2007-01-01

    Wood is an old and established consumption and construction material. It is still the most common material for constructing furniture, roofs, playgrounds and mine supports. In contrast to steel and concrete, wood warns of extreme loads by creaking. Its mechanical stability is more influenced by decay than by peripheral cracks. While external cracks are visible, internal decay by fungus growth is undetectable from outside. This may be a safety problem in supporting structures. The best analysis of the internal structure is provided by computed tomography, but this is also the most complex method, much more so than simple radiographic testing. However, the latter is made inaccurate by scattered radiation resulting from internal moisture. With the image processing options of digital radiographic techniques, the structural information can be separated effectively from noise. In contrast to X-ray and gamma radiography, neutron radiography provides information on the spatial distribution of moisture. In healthy wood, water is conducted in the sapwood while the hardwood is dry. Moisture in hardwood is caused by infestations, e.g. fungus growth. The contribution presents a comparative analysis of the available radiographic methods. (orig.)

  19. Large Format Radiographic Imaging

    International Nuclear Information System (INIS)

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

    1999-01-01

    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

  20. Triple-axis spectrometer

    International Nuclear Information System (INIS)

    Toeroek, Gy.

    2001-01-01

    A triple-axis spectrometer has been designed for structural and dynamical studies of condensed matter. Because of the limited number of other operational equipment the triple axis spectrometer was used in a multi purpose regime, e.g. high resolution diffractometry, strain analysis, reflectometry, quasielastic and inelastic scattering. A polarization setup was also tested on this spectrometer. (R.P.)

  1. Gut-brain axis

    NARCIS (Netherlands)

    Romijn, Johannes A.; Corssmit, Eleonora P.; Havekes, Louis M.; Pijl, Hanno

    2008-01-01

    To summarize recent studies on the regulation and the functions of the gut-brain axis. Visual cues of food and food intake interact with the gut-brain axis at the level of the hypothalamus. However, the hypothalamic response to glucose intake is considerably altered in patients with type 2 diabetes

  2. How to fake hydrodynamic signals

    Energy Technology Data Exchange (ETDEWEB)

    Romatschke, Paul [Department of Physics, 390 UCB, University of Colorado at Boulder, Boulder, CO (United States); Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309 (United States)

    2016-12-15

    Flow signatures in experimental data from relativistic ion collisions, are usually interpreted as a fingerprint of the presence of a hydrodynamic phase during the evolution of these systems. I review some theoretical ideas to ‘fake’ this hydrodynamic behavior in p+A and A+A collisions. I find that transverse flow and femtoscopic measurements can easily be forged through non-hydrodynamic evolution, while large elliptic flow requires some non-vanishing interactions in the hot phase.

  3. Foundations of radiation hydrodynamics

    CERN Document Server

    Mihalas, Dimitri

    1999-01-01

    Radiation hydrodynamics is a broad subject that cuts across many disciplines in physics and astronomy: fluid dynamics, thermodynamics, statistical mechanics, kinetic theory, and radiative transfer, among others. The theory developed in this book by two specialists in the field can be applied to the study of such diverse astrophysical phenomena as stellar winds, supernova explosions, and the initial phases of cosmic expansion, as well as the physics of laser fusion and reentry vehicles. As such, it provides students with the basic tools for research on radiating flows.Largely self-contained,

  4. Hydrodynamics of superfluid crystals

    International Nuclear Information System (INIS)

    Vardanyan, G.A.; Papoyan, K.V.; Sedrakyan, D.M.

    1984-01-01

    It is shown that three-velocity hydrodynamics equations describing the properties of a two-condensate crystal determine the low-frequency spectrum with allowance for superfluid drag. The drag on one superfluid component of density rho/sup( s/) 12 from another component of density rho/sup( s/) 22 , gives rise to two branches of vibrations of frequencies ω 1 and ω 2 , unlike the case of a one-condensate crystal. The absorption coefficient for transverse sound in a one-condensate crystal is expressed in terms of the quantum-mechanical characteristic quantity that describes the tunneling of atoms

  5. Radiographic scanning agent

    International Nuclear Information System (INIS)

    Bevan, J.A.

    1983-01-01

    This invention relates to radiodiagnostic agents and more particularly to a composition and method for preparing a highly effective technetium-99m-based bone scanning agent. One deficiency of x-ray examination is the inability of that technique to detect skeletal metastases in their incipient stages. It has been discovered that the methanehydroxydiphosphonate bone mineral-seeking agent is unique in that it provides the dual benefits of sharp radiographic imaging and excellent lesion detection when used with technetium-99m. This agent can also be used with technetium-99m for detecting soft tissue calcification in the manner of the inorganic phosphate radiodiagnostic agents

  6. Peritoneal tuberculosis: radiographic diagnosis

    Directory of Open Access Journals (Sweden)

    Carolina Ospina-Moreno

    2014-12-01

    Full Text Available Peritoneal tuberculosis (TB is an extrapulmonary form of presentation of tuberculosis. HIV infection is a primary risk factor for this condition. Diagnosis requires microbiological or histopathological confirmation in addition to supporting radiological imaging studies. Abdominal ultrasonography and CT are useful to obtain a radiographic diagnosis, with typical findings including diffuse peritoneal thickening, presence of ascites in varying volumes, adenopathies, and caseating nodes. We report 2 cases of patients with ascites and nodular peritoneal thickening on diagnostic images, as well as high CA-125 levels in laboratory tests. In both patients, a diagnosis of peritoneal tuberculosis was reached following a US-guided peritoneal biopsy.

  7. Anisotropic nonequilibrium hydrodynamic attractor

    Science.gov (United States)

    Strickland, Michael; Noronha, Jorge; Denicol, Gabriel S.

    2018-02-01

    We determine the dynamical attractors associated with anisotropic hydrodynamics (aHydro) and the DNMR equations for a 0 +1 d conformal system using kinetic theory in the relaxation time approximation. We compare our results to the nonequilibrium attractor obtained from the exact solution of the 0 +1 d conformal Boltzmann equation, the Navier-Stokes theory, and the second-order Mueller-Israel-Stewart theory. We demonstrate that the aHydro attractor equation resums an infinite number of terms in the inverse Reynolds number. The resulting resummed aHydro attractor possesses a positive longitudinal-to-transverse pressure ratio and is virtually indistinguishable from the exact attractor. This suggests that an optimized hydrodynamic treatment of kinetic theory involves a resummation not only in gradients (Knudsen number) but also in the inverse Reynolds number. We also demonstrate that the DNMR result provides a better approximation of the exact kinetic theory attractor than the Mueller-Israel-Stewart theory. Finally, we introduce a new method for obtaining approximate aHydro equations which relies solely on an expansion in the inverse Reynolds number. We then carry this expansion out to the third order, and compare these third-order results to the exact kinetic theory solution.

  8. Nanoscale hydrodynamics near solids

    Science.gov (United States)

    Camargo, Diego; de la Torre, J. A.; Duque-Zumajo, D.; Español, Pep; Delgado-Buscalioni, Rafael; Chejne, Farid

    2018-02-01

    Density Functional Theory (DFT) is a successful and well-established theory for the study of the structure of simple and complex fluids at equilibrium. The theory has been generalized to dynamical situations when the underlying dynamics is diffusive as in, for example, colloidal systems. However, there is no such a clear foundation for Dynamic DFT (DDFT) for the case of simple fluids in contact with solid walls. In this work, we derive DDFT for simple fluids by including not only the mass density field but also the momentum density field of the fluid. The standard projection operator method based on the Kawasaki-Gunton operator is used for deriving the equations for the average value of these fields. The solid is described as featureless under the assumption that all the internal degrees of freedom of the solid relax much faster than those of the fluid (solid elasticity is irrelevant). The fluid moves according to a set of non-local hydrodynamic equations that include explicitly the forces due to the solid. These forces are of two types, reversible forces emerging from the free energy density functional, and accounting for impenetrability of the solid, and irreversible forces that involve the velocity of both the fluid and the solid. These forces are localized in the vicinity of the solid surface. The resulting hydrodynamic equations should allow one to study dynamical regimes of simple fluids in contact with solid objects in isothermal situations.

  9. Load responsive hydrodynamic bearing

    Science.gov (United States)

    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.

  10. Interpreting radiographs. 4. The carpus

    International Nuclear Information System (INIS)

    Burguez, P.N.

    1984-01-01

    The complexity of the carpus which has three major joints, seven or eight carpal bones and five adjacent bones, each of which articulates with one or more of the carpal elements, necessitates good quality radiographs for definitive radiographic interpretation may be extremely difficult because of the disparity between radiographic changes and obvious clinical signs and, therefore, must be discussed in the light of a thorough clinical assessment

  11. Anomalous hydrodynamics in two dimensions

    Indian Academy of Sciences (India)

    Keywords. Anomalous hydrodynamics; gauge anomaly; gravitational anomaly. PACS No. 47.10.ab. The chiral anomaly has played a ubiquitous role in modern physics. It has found appli- cations in several diverse fields like quantum wires, quantum Hall effect, chiral magnetic effect and anomalous hydrodynamics, to name ...

  12. Black brane entropy and hydrodynamics

    NARCIS (Netherlands)

    Booth, I.; Heller, M.P.; Spaliński, M.

    2010-01-01

    A generalization of entropy to near-equilibrium phenomena is provided by the notion of a hydrodynamic entropy current. Recent advances in holography have lead to the formulation of fluid-gravity duality, a remarkable connection between the hydrodynamics of certain strongly coupled media and dynamics

  13. Radiographer interpretation of trauma radiographs: Issues for radiography education providers

    International Nuclear Information System (INIS)

    Hardy, Maryann; Snaith, Beverly

    2009-01-01

    Background: The role of radiographers with respect to image interpretation within clinical practice is well recognised. It is the expectation of the professional, regulatory and academic bodies that upon qualification, radiographers will possess image interpretation skills. Additionally, The College of Radiographers has asserted that its aspiration is for all radiographers to be able to provide an immediate written interpretation on skeletal trauma radiographs by 2010. This paper explores the readiness of radiography education programmes in the UK to deliver this expectation. Method: A postal questionnaire was distributed to 25 Higher Education Institutions in the UK (including Northern Ireland) that provided pre-registration radiography education as identified from the Society and College of Radiographers register. Information was sought relating to the type of image interpretation education delivered at pre- and post-registration levels; the anatomical range of image interpretation education; and education delivery styles. Results: A total of 19 responses (n = 19/25; 76.0%) were received. Image interpretation education was included as part of all radiographer pre-registration programmes and offered at post-registration level at 12 academic centres (n = 12/19; 63.2%). The anatomical areas and educational delivery methods varied across institutions. Conclusion: Radiography education providers have embraced the need for image interpretation education within both pre- and post-registration radiography programmes. As a result, UK education programmes are able to meet the 2010 College of Radiographers aspiration.

  14. Hydrodynamics of Peristaltic Propulsion

    Science.gov (United States)

    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.

  15. From TDHF to hydrodynamics

    International Nuclear Information System (INIS)

    Koehler, H.S.

    1983-01-01

    The Time-Dependent Hartree-Fock theory provides a microscopic approach to the scattering of heavy ions. Fundamental in this theory is a mean-(one-body) field. The calculation of this field from a two-body effective interaction makes the theory microscopic. Many-body effects are included by the Brueckner definition of this interaction; the reaction-matrix. In excited media it is in general complex allowing for decays. The imaginary part relates directly to the collision-term in a transport equation. We treat this term by the time-relaxation-method. This implies an extension of the TDHF-equation to include two-body collisions. Hydrodynamic equations are derived from this new equation. The solution of the two equations agree quantitatively for short-relaxation-times. Relaxation-times are calculated as a function of temperature. (orig.)

  16. Hydrodynamic effects on coalescence.

    Energy Technology Data Exchange (ETDEWEB)

    Dimiduk, Thomas G.; Bourdon, Christopher Jay; Grillet, Anne Mary; Baer, Thomas A.; de Boer, Maarten Pieter; Loewenberg, Michael (Yale University, New Haven, CT); 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.

  17. Hydrodynamics of sediment threshold

    Science.gov (United States)

    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. Odontogenic keratocyst radiographic features

    International Nuclear Information System (INIS)

    Nartey, N. O.; Saini, T.

    1990-01-01

    The clinical features often patients with odontogenic keratocysts were studied. One patient had Gorlin-GoJtz syndrome. A total of fourteen radiolucent lesions were observed on radiographic examination. All the fourteen lesions were diagnosed as odontogenic keratocyst after histopathclogical examination of biopsied tissue from the patients. The age at diagnosis ranged from 25-72 years with a mean age of 37.6 years. The male : female ratio was 2.3:1. Thirteen of these lesions occurred in the mandible, nine involved the mandibular third molar region. Involvement of the ramus of the mandible produced a sausage-shaped radiolucency. Cystic lesions which have been present for long periods of time showed scalloped margins, due to the regional resorption of the surrounding bone. The bony ledges present on the cortical bones simulated multilocular appearance in such cases. It was also observed that the lesions in older individuals perforated the cortical plates rather than eliciting a periostally induced bony expansion. (author)

  19. Radiographic contrast media

    International Nuclear Information System (INIS)

    Golman, K.; Holtz, E.; Almen, T.

    1987-01-01

    Contrast media are used in diagnostic radiology to enhance the X-ray attenuation between a body structure of interest and the surrounding tissue. A detail becomes perceptible on a roentgenogram only when its contrast exceeds a minimum value in relation to the background. Small areas of interest must have higher contrast than the background. The contrast effect depends on concentration of the contrast media with the body. A high contrast media concentration difference thus gives rise to more morphological details in the radiographs. Contrast media can be divided into negative contrast media such as air and gas which attenuate X-rays less than the body tissues, and positive contrast materials which attenuate X-rays more than the body tissues. The positive contrast media all contain either iodine (atomic number 53) or barium (atomic number 56) and can be divided into water-insoluble and water-soluble contrast media

  20. A radiographic examination system

    International Nuclear Information System (INIS)

    Cable, A.P.; Cable, W.S.

    1983-01-01

    A system for performing radiographic examination, particularly of large items such as international container units is disclosed. The system is formed as an installation comprising housings for respective linear accelerators transmitting a beam of radiation across the path of a conveyor along which the units can be displaced continuously or incrementally. On either end of the installation are container handling areas including roller conveyors with drag chains and transverse manipulators, and the whole installation is secured within automatically operated doors which seal the high energy region when a container on the conveyor is being subjected to examination. The radiation transmitted through a container is detected in a detector system incorporating a fluoroscopic screen light output from which is detected in a camera system such as a television camera, and transmitted as coded pulsed signals by a coding transfer unit to display screens where an image of the transmitted information can be displayed and/or recorded for further use. (author)

  1. Clavicle segmentation in chest radiographs

    NARCIS (Netherlands)

    Hogeweg, L.E.; Sanchez, C.I.; Jong, P.A. de; Maduskar, P.; Ginneken, B. van

    2012-01-01

    Automated delineation of anatomical structures in chest radiographs is difficult due to superimposition of multiple structures. In this work an automated technique to segment the clavicles in posterior-anterior chest radiographs is presented in which three methods are combined. Pixel classification

  2. Surface dose extrapolation measurements with radiographic film

    International Nuclear Information System (INIS)

    Butson, Martin J; Cheung Tsang; Yu, Peter K N; Currie, Michael

    2004-01-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. (note)

  3. Chesneys' radiographic imaging. 5. ed.

    International Nuclear Information System (INIS)

    Ball, J.; Price, T.

    1989-01-01

    This new edition of Chesney and Chesney: Radiographic Imaging has been completely written by two new authors. The book reflects the change in emphasis in radiology from photographic processes towards electronic imaging methods. There is new material on image intensifiers and television imaging, digital imaging and digital subtractions. Analyses of the various characteristics of, and defects in, images on radiographs, xeroradiographs and the television screen are included. The methods, equipment and materials used to record the cathode ray tube image are described and there is new material on the principles of alternative diagnostic imaging techniques such as ultrasound, computed tomography and radionuclide imaging which provide cathode ray tube images. The book is primarily for student radiographers studying for the Diploma of the College of Radiographers, but radiographers studying for postdiplomate qualifications such as the Higher Diploma (HDCR) will also find the book helpful. (author)

  4. SPECIAL RELATIVISTIC HYDRODYNAMICS WITH GRAVITATION

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jai-chan [Department of Astronomy and Atmospheric Sciences, Kyungpook National University, Daegu (Korea, Republic of); Noh, Hyerim [Korea Astronomy and Space Science Institute, Daejon (Korea, Republic of)

    2016-12-20

    Special relativistic hydrodynamics with weak gravity has hitherto been unknown in the literature. Whether such an asymmetric combination is possible has been unclear. Here, the hydrodynamic equations with Poisson-type gravity, considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit, are consistently derived from Einstein’s theory of general relativity. An analysis is made in the maximal slicing, where the Poisson’s equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the general hypersurface condition. Our formulation includes the anisotropic stress.

  5. Special Relativistic Hydrodynamics with Gravitation

    Science.gov (United States)

    Hwang, Jai-chan; Noh, Hyerim

    2016-12-01

    Special relativistic hydrodynamics with weak gravity has hitherto been unknown in the literature. Whether such an asymmetric combination is possible has been unclear. Here, the hydrodynamic equations with Poisson-type gravity, considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit, are consistently derived from Einstein’s theory of general relativity. An analysis is made in the maximal slicing, where the Poisson’s equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the general hypersurface condition. Our formulation includes the anisotropic stress.

  6. Hydrodynamic force microscopy

    Science.gov (United States)

    Ulrich, Elaine Schmid

    Microfluidic networks and microporous materials have long been of interest in areas such as hydrology, petroleum engineering, chemical and electrochemical engineering, medicine and biochemical engineering. With the emergence of new processes in gas separation, cell sorting, ultrafiltration, and advanced materials synthesis, the importance of building a better qualitative and quantitative understanding of these key technologies has become apparent. However, microfluidic measurement and theory is still relatively underdeveloped, presenting a significant obstacle to the systematic design of microfluidic devices and materials. Theoretical challenges arise from the breakdown of classical viscous flow models as the flow dimensions approach the mean free path of individual molecules. Experimental challenges arise from the lack of flow profilometry techniques at sub-micron length scales. Here we present an extension of scanning probe microscopy techniques, which we have termed Hydrodynamic Force Microscopy (HFM). HFM exploits fluid drag to profile microflows and to map the permeability of microporous materials. In this technique, an atomic force microscope (AFM) cantilever is scanned close to a microporous sample surface. The hydrodynamic interactions arising from a pressure-driven flow through the sample are then detected by mapping the deflection of an AFM cantilever. For gas flows at atmospheric pressure, HFM has been shown to achieve a velocity sensitivity of 1 cm/s with a spatial resolution of ˜ 10 nm. This compares very favorably to established techniques such as hot-wire and laser Doppler anemometry, whose spatial resolutions typically exceed 1 mum and which may rely on the use of tracer particles or flow markers1. We demonstrate that HFM can successfully profile Poiseuille flows inside pores as small as 100 nm and can distinguish Poiseuille flow from uniform flow for short entry lengths. HFM detection of fluid jets escaping from porous samples can also reveal a

  7. Engineering Hydrodynamic AUV Hulls

    Science.gov (United States)

    Allen, J.

    2016-12-01

    AUV stands for autonomous underwater vehicle. AUVs are used in oceanography and are similar to gliders. MBARIs AUVs as well as other AUVs map the ocean floor which is very important. They also measure physical characteristics of the water, such as temperature and salinity. My science fair project for 4th grade was a STEM activity in which I built and tested 3 different AUV bodies. I wanted to find out which design was the most hydrodynamic. I tested three different lengths of AUV hulls to see which AUV would glide the farthest. The first was 6 inches. The second was 12 inches and the third was 18 inches. I used clay for the nosecone and cut a ruler into two and made it the fin. Each AUV used the same nosecone and fin. I tested all three designs in a pool. I used biomimicry to create my hypothesis. When I was researching I found that long slim animals swim fastest. So, my hypothesis is the longer AUV will glide farthest. In the end I was right. The longer AUV did glide the farthest.

  8. Advanced in Macrostatistical Hydrodynamics

    International Nuclear Information System (INIS)

    Graham, A.L.; Tetlow, N.; Abbott, J.R.; Mondy, L.S.; Brenner, H.

    1993-01-01

    An overview is presented of research that focuses on slow flows of suspensions in which colloidal and inertial effects are negligibly small (Macrostatistical Hydrodynamics). First, we describe nuclear magnetic resonance imaging experiments to quantitatively measure particle migration occurring in concentrated suspensions undergoing a flow with a nonuniform shear rate. These experiments address the issue of how the flow field affects the microstructure of suspensions. In order to understand the local viscosity in a suspension with such a flow-induced, spatially varying concentration, one must know how the viscosity of a homogeneous suspension depends on such variables as solids concentration and particle orientation. We suggest the technique of falling ball viscometry, using small balls, as a method to determine the effective viscosity of a suspension without affecting the original microstructure significantly. We also describe data from experiments in which the detailed fluctuations of a falling ball's velocity indicate the noncontinuum nature of the suspension and may lead to more insights into the effects of suspension microstructure on macroscopic properties. Finally, we briefly describe other experiments that can be performed in quiescent suspensions (in contrast to the use of conventional shear rotational viscometers) in order to learn more about the microstructure and boundary effects in concentrated suspensions

  9. Lotic Water Hydrodynamic Model

    Energy Technology Data Exchange (ETDEWEB)

    Judi, David Ryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tasseff, Byron Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-01-23

    Water-related natural disasters, for example, floods and droughts, are among the most frequent and costly natural hazards, both socially and economically. Many of these floods are a result of excess rainfall collecting in streams and rivers, and subsequently overtopping banks and flowing overland into urban environments. Floods can cause physical damage to critical infrastructure and present health risks through the spread of waterborne diseases. Los Alamos National Laboratory (LANL) has developed Lotic, a state-of-the-art surface water hydrodynamic model, to simulate propagation of flood waves originating from a variety of events. Lotic is a two-dimensional (2D) flood model that has been used primarily for simulations in which overland water flows are characterized by movement in two dimensions, such as flood waves expected from rainfall-runoff events, storm surge, and tsunamis. In 2013, LANL developers enhanced Lotic through several development efforts. These developments included enhancements to the 2D simulation engine, including numerical formulation, computational efficiency developments, and visualization. Stakeholders can use simulation results to estimate infrastructure damage and cascading consequences within other sets of infrastructure, as well as to inform the development of flood mitigation strategies.

  10. Hydrodynamics of electrons in graphene

    Science.gov (United States)

    Lucas, Andrew; Chung Fong, Kin

    2018-02-01

    Generic interacting many-body quantum systems are believed to behave as classical fluids on long time and length scales. Due to rapid progress in growing exceptionally pure crystals, we are now able to experimentally observe this collective motion of electrons in solid-state systems, including graphene. We present a review of recent progress in understanding the hydrodynamic limit of electronic motion in graphene, written for physicists from diverse communities. We begin by discussing the ‘phase diagram’ of graphene, and the inevitable presence of impurities and phonons in experimental systems. We derive hydrodynamics, both from a phenomenological perspective and using kinetic theory. We then describe how hydrodynamic electron flow is visible in electronic transport measurements. Although we focus on graphene in this review, the broader framework naturally generalizes to other materials. We assume only basic knowledge of condensed matter physics, and no prior knowledge of hydrodynamics.

  11. Hydrodynamic aspects of flotation separation

    Directory of Open Access Journals (Sweden)

    Peleka Efrosyni N.

    2016-01-01

    Full Text Available Flotation separation is mainly used for removing particulates from aqueous dispersions. It is widely used for ore beneficiation and recovering valuable materials. This paper reviews the hydrodynamics of flotation separations and comments on selected recent publications. Units are distinguished as cells of ideal and non-ideal flow. A brief introduction to hydrodynamics is included to explain an original study of the hybrid flotation-microfiltration cell, effective for heavy metal ion removal.

  12. An introduction to astrophysical hydrodynamics

    CERN Document Server

    Shore, Steven N

    1992-01-01

    This book is an introduction to astrophysical hydrodynamics for both astronomy and physics students. It provides a comprehensive and unified view of the general problems associated with fluids in a cosmic context, with a discussion of fluid dynamics and plasma physics. It is the only book on hydrodynamics that addresses the astrophysical context. Researchers and students will find this work to be an exceptional reference. Contents include chapters on irrotational and rotational flows, turbulence, magnetohydrodynamics, and instabilities.

  13. Radiographic scanner apparatus

    International Nuclear Information System (INIS)

    Wake, R.H.

    1980-01-01

    The preferred embodiment of this invention includes a hardware system, or processing means, which operates faster than software. Moreover the computer needed is less expensive and smaller. Radiographic scanner apparatus is described for measuring the intensity of radiation after passage through a planar region and for reconstructing a representation of the attenuation of radiation by the medium. There is a source which can be rotated, and detectors, the output from which forms a data line. The detectors are disposed opposite the planar region from the source to produce a succession of data lines corresponding to the succession of angular orientations of the source. There is a convolver means for convolving each of these data lines, with a filter function, and a means of processing the convolved data lines to create the representation of the radiation attenuation in the planar region. There is also apparatus to generate a succession of data lines indicating radiation attenuation along a determinable path with convolver means. (U.K.)

  14. Chest radiographic findings of leptospirosis

    International Nuclear Information System (INIS)

    Kim, Mee Hyun; Jung, Hee Tae; Lee, Young Joong; Yoon, Jong Sup

    1986-01-01

    1. A study on chest radiographic findings of 54 cases with pneumonia like symptoms was performed. Of 54 cases, 8 cases were confirmed to be leptospirosis and 7 cases were leptospirosis combined with Korean hemorrhagic fever. 2. Of 8 cases of leptospirosis, 4 cases showed abnormal chest radiographic findings: acinar nodular type 2, massive confluent consolidation type 2. Of 7 cases of leptospirosis combined with Korean hemorrhagic fever: acinar nodular type 3, massive confluent consolidation type 1, and increased interstitial markings type 1 respectively. 3. It was considered to be difficult to diagnose the leptospirosis on chest radiographic findings alone, especially the case combined with Korean hemorrhagic fever.

  15. The radiographic image: A cultural artefact?

    International Nuclear Information System (INIS)

    Strudwick, Ruth M.

    2014-01-01

    This article looks at the role of the radiographic images produced by diagnostic radiographers. An ethnographic study of the workplace culture in one diagnostic imaging department was undertaken using participant observation for four months and semi-structured interviews with ten key informants. One of the key themes; that of the radiographic image as a cultural artefact, is explored in this article. The radiographic image is a cultural artefact which radiographers are protective of and take ownership of. Radiographers are conscious of the quality of their images and the images are an important aspect of their work. Radiographers take criticism of their images personally. The radiographic image is a record of the interaction that occurs between the radiographer and the patient. The way in which radiographic images are viewed, used and judged is an important aspect of the role of diagnostic radiographer

  16. Scanning radiographic apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Albert, R.D.

    1980-04-01

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

  17. Method for taking X radiographs

    International Nuclear Information System (INIS)

    Orth, G.

    1983-01-01

    The method is aimed at obtaining X radiographs of any human organ with the aid of an X-ray-shadowless radiation detector of a dose measuring device, which is arranged between patient and imaging system, and of a controlling microprocessor system, so that the image-forming parameters are automatically adjusted to the specific properties of the patient. This procedure minimices the efforts in preparing the radiograph and the radiation exposure of the patient

  18. Flow and Convective Heat Transfer of Cylinder Misaligned from Aerodynamic Axis of Cyclone Flow

    Directory of Open Access Journals (Sweden)

    I. L. Leukhin

    2008-01-01

    Full Text Available The paper provides and analyzes results of experimental investigations on physical specific features of hydrodynamics and convective heat transfer of a cyclone flow with a group of round cylinders located symmetrically relative to its aerodynamic axis, calculative equations for average and local heat transfer factors at characteristic sections of cylinder surface.

  19. Numerical Hydrodynamics in Special Relativity

    Directory of Open Access Journals (Sweden)

    Martí José Maria

    2003-01-01

    Full Text Available This review is concerned with a discussion of numerical methods for the solution of the equations of special relativistic hydrodynamics (SRHD. Particular emphasis is put on a comprehensive review of the application of high-resolution shock-capturing methods in SRHD. Results of a set of demanding test bench simulations obtained with different numerical SRHD methods are compared. Three applications (astrophysical jets, gamma-ray bursts and heavy ion collisions of relativistic flows are discussed. An evaluation of various SRHD methods is presented, and future developments in SRHD are analyzed involving extension to general relativistic hydrodynamics and relativistic magneto-hydrodynamics. The review further provides FORTRAN programs to compute the exact solution of a 1D relativistic Riemann problem with zero and nonzero tangential velocities, and to simulate 1D relativistic flows in Cartesian Eulerian coordinates using the exact SRHD Riemann solver and PPM reconstruction.

  20. Soliton Gases and Generalized Hydrodynamics

    Science.gov (United States)

    Doyon, Benjamin; Yoshimura, Takato; Caux, Jean-Sébastien

    2018-01-01

    We show that the equations of generalized hydrodynamics (GHD), a hydrodynamic theory for integrable quantum systems at the Euler scale, emerge in full generality in a family of classical gases, which generalize the gas of hard rods. In this family, the particles, upon colliding, jump forward or backward by a distance that depends on their velocities, reminiscent of classical soliton scattering. This provides a "molecular dynamics" for GHD: a numerical solver which is efficient, flexible, and which applies to the presence of external force fields. GHD also describes the hydrodynamics of classical soliton gases. We identify the GHD of any quantum model with that of the gas of its solitonlike wave packets, thus providing a remarkable quantum-classical equivalence. The theory is directly applicable, for instance, to integrable quantum chains and to the Lieb-Liniger model realized in cold-atom experiments.

  1. Anomalous hydrodynamics of Weyl materials

    Science.gov (United States)

    Monteiro, Gustavo; Abanov, Alexander

    Kinetic theory is a useful tool to study transport in Weyl materials when the band-touching points are hidden inside a Fermi surface. It accounts, for example, for the negative magnetoresistance caused by the chiral magnetic effect and quantum oscillations (SdH effect) in the magnetoresistance together within the same framework. As an alternative approach to kinetic theory we also consider the regime of strong interactions where hydrodynamics can be applicable. A variational principle of these hydrodynamic equations can be found in and provide a natural framework to study hydrodynamic surface modes which correspond to the strongly-interacting physics signature of Fermi arcs. G.M. acknowledges the financial support from FAPESP.

  2. Quantum Plasmas An Hydrodynamic Approach

    CERN Document Server

    Haas, Fernando

    2011-01-01

    This book provides an overview of the basic concepts and new methods in the emerging scientific area known as quantum plasmas. In the near future, quantum effects in plasmas will be unavoidable, particularly in high density scenarios such as those in the next-generation intense laser-solid density plasma experiment or in compact astrophysics objects. Currently, plasmas are in the forefront of many intriguing questions around the transition from microscopic to macroscopic modeling of charged particle systems. Quantum Plasmas: an Hydrodynamic Approach is devoted to the quantum hydrodynamic model paradigm, which, unlike straight quantum kinetic theory, is much more amenable to investigate the nonlinear realm of quantum plasmas. The reader will have a step-by-step construction of the quantum hydrodynamic method applied to plasmas. The book is intended for specialists in classical plasma physics interested in methods of quantum plasma theory, as well as scientists interested in common aspects of two major areas of...

  3. Vertical axis wind turbine

    International Nuclear Information System (INIS)

    Obretenov, V.; Tsalov, T.; Chakarov, T.

    2012-01-01

    In recent years, the interest in wind turbines with vertical axis noticeably increased. They have some important advantages: low cost, relatively simple structure, reliable packaging system of wind aggregate long period during which require no maintenance, low noise, independence of wind direction, etc.. The relatively low efficiency, however, makes them applicable mainly for small facilities. The work presents a methodology and software for approximately aerodynamic design of wind turbines of this type, and also analyzed the possibility of improving the efficiency of their workflow

  4. Vertical axis wind turbines

    Science.gov (United States)

    Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

    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.

  5. A radiographic study of mental foramen in intraoral radiographs

    International Nuclear Information System (INIS)

    Sohn, Jeong Ick; Choi, Karp Shik

    1995-01-01

    The purpose of this study was to evaluate the position and shape of mental foramen in periapical radiographs. For this study, periapical radiographs of premolar areas were obtained from the 200 adults. Accordingly, the positional and shape changes of mental foramen were evaluated. The authors obtained radiographs according to changes in radiation beam direction in periapical radiographs of premolar areas, and then evaluated the positional and shape changes of mental foramen. The following results were obtained: 1. Shapes of mental foramen were observed elliptical (34.3%), round or oval (28.0%), unidentified (25.5%) and diffuse (12.2%) type in descending order of frequency. 2, Horizontal positions of mental foramen were most frequently observed at the 2nd premolar area (55.3%), the area between the 1st premolar and 2nd premolar (39.6%), the area between the 2nd premolar and 1st molar (3.4%), the 1st premolar area (1.0%), the area between the canine and 1st premolar (0.7%) in descending order of frequency. 3. Vertical positions of mental foramen were most frequently observed at the inferior to apex (67.1%), and at apex (24.8%), overlap with apex (6.4%), superior to apex (1.7%) in descending order of frequency. 4. Shapes of mental foramen were more obviously observed at the upward 10 degree positioned periapical radiographs. And according to the changes of horizontal and vertical position, they were observed similar to normally positioned periapical radiographs.

  6. A radiographic study of mental foramen in intraoral radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Jeong Ick; Choi, Karp Shik [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of)

    1995-08-15

    The purpose of this study was to evaluate the position and shape of mental foramen in periapical radiographs. For this study, periapical radiographs of premolar areas were obtained from the 200 adults. Accordingly, the positional and shape changes of mental foramen were evaluated. The authors obtained radiographs according to changes in radiation beam direction in periapical radiographs of premolar areas, and then evaluated the positional and shape changes of mental foramen. The following results were obtained: 1. Shapes of mental foramen were observed elliptical (34.3%), round or oval (28.0%), unidentified (25.5%) and diffuse (12.2%) type in descending order of frequency. 2, Horizontal positions of mental foramen were most frequently observed at the 2nd premolar area (55.3%), the area between the 1st premolar and 2nd premolar (39.6%), the area between the 2nd premolar and 1st molar (3.4%), the 1st premolar area (1.0%), the area between the canine and 1st premolar (0.7%) in descending order of frequency. 3. Vertical positions of mental foramen were most frequently observed at the inferior to apex (67.1%), and at apex (24.8%), overlap with apex (6.4%), superior to apex (1.7%) in descending order of frequency. 4. Shapes of mental foramen were more obviously observed at the upward 10 degree positioned periapical radiographs. And according to the changes of horizontal and vertical position, they were observed similar to normally positioned periapical radiographs.

  7. Attitudes of radiographers to radiographer-led discharge: A survey

    International Nuclear Information System (INIS)

    Lumsden, Laura; Cosson, Philip

    2015-01-01

    Background: The traditional role of the Diagnostic Radiographer in image acquisition has gradually been extended through skill-mix, particularly to include abnormality detection. Aims: This research focused on the attitudes of Radiographers to Radiographer-led Discharge (RLD), where Radiographers discharge patients with minor injuries and perform tasks previously undertaken by Accident and Emergency staff. The effects of job role, hospital type, experience and whether RLD was used in the participant's trust were examined. Method: A multiple-indicator online questionnaire assessed attitudes to RLD. Snowball sampling was used with advertisement via emails, posters and cards, containing Quick Response (QR) codes. Statement responses were coded, with reverse coding for negative statements and total scores were calculated. A higher score represented a more positive attitude. Results: 101 questionnaires were completed (an estimated 30% response rate) and the mean total score was 84/115. 95% of participants supported radiographer involvement in abnormality detection, with 46.5% selecting RLD as the preferred system for minor injuries patients vs 48.5% preferring commenting alone. Discussion: Participants were positive about extending their role through RLD and felt confident in their image interpretation abilities, though expressed concern for the legal consequences of the role and adequate pay. Generalization of the results is limited due to the possible low response rate. Conclusion: Overall, participants demonstrated positive attitudes towards RLD but they also indicate the need for appropriate payment for any additional responsibility. These findings are promising for successful implementation of RLD, though larger-scale research including radiologists, business managers, A and E staff and patients would be beneficial. - Highlights: • 101 questionnaires were completed (an estimated 30% response rate). • 95% of participants supported radiographer involvement

  8. Hydrodynamics of oceans and atmospheres

    CERN Document Server

    Eckart, Carl

    1960-01-01

    Hydrodynamics of Oceans and Atmospheres is a systematic account of the hydrodynamics of oceans and atmospheres. Topics covered range from the thermodynamic functions of an ideal gas and the thermodynamic coefficients for water to steady motions, the isothermal atmosphere, the thermocline, and the thermosphere. Perturbation equations, field equations, residual equations, and a general theory of rays are also presented. This book is comprised of 17 chapters and begins with an introduction to the basic equations and their solutions, with the aim of illustrating the laws of dynamics. The nonlinear

  9. Anisotropic hydrodynamics: Motivation and methodology

    Energy Technology Data Exchange (ETDEWEB)

    Strickland, Michael

    2014-06-15

    In this proceedings contribution I review recent progress in our understanding of the bulk dynamics of relativistic systems that possess potentially large local rest frame momentum-space anisotropies. In order to deal with these momentum-space anisotropies, a reorganization of relativistic viscous hydrodynamics can be made around an anisotropic background, and the resulting dynamical framework has been dubbed “anisotropic hydrodynamics”. I also discuss expectations for the degree of momentum-space anisotropy of the quark–gluon plasma generated in relativistic heavy ion collisions at RHIC and LHC from second-order viscous hydrodynamics, strong-coupling approaches, and weak-coupling approaches.

  10. Industrial radiography on radiographic paper

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1977-11-01

    An investigation was performed to compare the quality of radiographic paper with that of X-ray film, after a review had been made of the rather scarce literature on the subject. The equipment used throughout the investigation is described, and characteristic curves for Agfa-Gevaert and Kodak papers exposed with different intensifying screens in the low and intermediate voltage range are reproduced. The relative speed, contrast and exposure latitude were computed from these curves. The quality of the radiographic image was checked on U/Al blocks and plates, Al and Fe blocks, and fiber-reinforced composites. Exposure charts for Al and Fe were made for various paper and screen combinations. Both the sharpness of the radiographic image as well as the influence of processing on speed and contrast were checked. Examples are given of the practical application of the paper for radiography of castings, weldings, solderings, assemblies, etc. (author)

  11. Caries detection in dental radiographs

    International Nuclear Information System (INIS)

    Dunn, S.M.

    1987-01-01

    Caries, or the decay of teeth are difficult to automatically detect in dental radiographs because of the small area of the image that is occupied by the decay. Images of dental radiographs has distinct regions of homogeneous gray levels, and therefore naturally lead to a segmentation based automatic caries detection algorithm. This paper describes a method for caries detection based on a multiclass, area independent thresholding and segmenting scheme. This multiclass thresholding algorithm is an extension of the uniform error threshold, an area independent, distribution free thresholding method used for images of only two classes of objects. The authors first consider the problem of caries detection and the image features that characterize the presence of caries. Next, the uniform error threshold is reviewed, and the general multiclass uniform error threshold algorithm is presented. This algorithm is used to automatically detect caries in dental radiographs

  12. Digital image analysis of NDT radiographs

    International Nuclear Information System (INIS)

    Graeme, W.A. Jr.; Eizember, A.C.; Douglass, J.

    1989-01-01

    Prior to the introduction of Charge Coupled Device (CCD) detectors the majority of image analysis performed on NDT radiographic images was done visually in the analog domain. While some film digitization was being performed, the process was often unable to capture all the usable information on the radiograph or was too time consuming. CCD technology now provides a method to digitize radiographic film images without losing the useful information captured in the original radiograph in a timely process. Incorporating that technology into a complete digital radiographic workstation allows analog radiographic information to be processed, providing additional information to the radiographer. Once in the digital domain, that data can be stored, and fused with radioscopic and other forms of digital data. The result is more productive analysis and management of radiographic inspection data. The principal function of the NDT Scan IV digital radiography system is the digitization, enhancement and storage of radiographic images

  13. PACS influence the radiographer's work

    International Nuclear Information System (INIS)

    Fridell, Kent; Aspelin, Peter; Edgren, Lars; Lindskoeld, Lars; Lundberg, Nina

    2009-01-01

    Radiological departments are changing rapidly due to the implementation of digital images and PACS (Picture Archiving and Communication Systems). The introduction of new technology seems to dissolve boundaries between the professions in the work environment where the technology is introduced. This process tends to change the organization and its routines. The aim of this qualitative study is to explore changes in radiographers' work with regard to skills, work practice and technology. The study used open-ended interviews to explore the radiographers' perceptions of such changes, and to identify problems and solutions pertaining to work practice. Inspiration is taken from grounded theory to explain the changes in work that were found. Respondents were selected from a total of 133 potential participants as a theoretical or purposive sample. The changing trends within the professional role indicated that radiographers, as image producers, shifted their focus from the ability to set the optimal exposure parameters in order to obtain the optimal image for diagnosis to become expert in exposure parameters, projection techniques and diagnostic practice, having multifaceted skills, as being the jack of all trades. When implementing PACS there was an obvious change in image production. At the start there were visions of new routines, and therefore the radiographers became early adopters to the new technology; in practice the organization was stacked in old routines, as the routines were inflexible and PACS work was pushed into old work routines. Although inflexible, this does not mean that they cannot change, and obviously in 2006 new routines had been implemented making it possible for the radiographers in finding new ways for collaborating with colleagues. The new technology immediately created a vision of improved service to the clinicians. In order to optimize the service the radiographers developed an insight into the need for a more comprehensive change in work using

  14. Anomalous hydrodynamics in two dimensions

    Indian Academy of Sciences (India)

    Abstract. A new approach is presented to discuss two-dimensional hydrodynamics with gauge and gravitational anomalies. Exact constitutive relations for the stress tensor and charge current are obtained. Also, a connection between response parameters and anomaly coefficients is discussed. These are new results which, ...

  15. Hydrodynamics of spatially ordered superfluids

    NARCIS (Netherlands)

    Stoof, H.T.C.; Mullen, K.; Wallin, M.; Girvin, S.M.

    1996-01-01

    We derive the hydrodynamic equations for the supersolid and superhexatic phases of a neutral two-dimensional Bose fluid. We find, assuming that the normal part of the fluid is clamped to an underlying substrate, that both phases can sustain third-sound modes and that in the supersolid phase there

  16. Anomalous hydrodynamics in two dimensions

    Indian Academy of Sciences (India)

    2016-01-14

    Jan 14, 2016 ... A new approach is presented to discuss two-dimensional hydrodynamics with gauge and gravitational anomalies. Exact constitutive relations for the stress tensor and charge current are obtained. Also, a connection between response parameters and anomaly coefficients is discussed. These are new ...

  17. Numerical Hydrodynamics in General Relativity

    Directory of Open Access Journals (Sweden)

    Font José A.

    2003-01-01

    Full Text Available The current status of numerical solutions for the equations of ideal general relativistic hydrodynamics is reviewed. With respect to an earlier version of the article, the present update provides additional information on numerical schemes, and extends the discussion of astrophysical simulations in general relativistic hydrodynamics. Different formulations of the equations are presented, with special mention of conservative and hyperbolic formulations well-adapted to advanced numerical methods. A large sample of available numerical schemes is discussed, paying particular attention to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. A comprehensive summary of astrophysical simulations in strong gravitational fields is presented. These include gravitational collapse, accretion onto black holes, and hydrodynamical evolutions of neutron stars. The material contained in these sections highlights the numerical challenges of various representative simulations. It also follows, to some extent, the chronological development of the field, concerning advances on the formulation of the gravitational field and hydrodynamic equations and the numerical methodology designed to solve them.

  18. Radiation hydrodynamics in the laboratory

    International Nuclear Information System (INIS)

    1985-12-01

    This report contains a collection of five preprints devoted to the subject of laser induced phenomena of radiation hydrodynamics. These preprints cover approximately the contents of the presentations made by the MPQ experimental laser-plasma group at the 17th European Conference on Laser Interaction with Matter (ECLIM), Rome, November 18-22, 1985. (orig.)

  19. Hydrodynamics of a quark droplet

    DEFF Research Database (Denmark)

    Bjerrum-Bohr, Johan J.; Mishustin, Igor N.; Døssing, Thomas

    2012-01-01

    We present a simple model of a multi-quark droplet evolution based on the hydrodynamical description. This model includes collective expansion of the droplet, effects of the vacuum pressure and surface tension. The hadron emission from the droplet is described following Weisskopf's statistical...

  20. Hydrodynamic stability and stellar oscillations

    Indian Academy of Sciences (India)

    Chandrasekhar's monograph on Hydrodynamic and hydromagnetic stability, published in 1961, is a standard ... the Astrophysics Data System shows about 2500 citations to this monograph and what is remarkable is that ... form the bulk of the book are devoted to convection, or the thermal instability of a layer of fluid heated ...

  1. Hydrodynamic instabilities in inertial fusion

    International Nuclear Information System (INIS)

    Hoffman, N.M.

    1994-01-01

    This report discusses topics on hydrodynamics instabilities in inertial confinement: linear analysis of Rayleigh-Taylor instability; ablation-surface instability; bubble rise in late-stage Rayleigh-Taylor instability; and saturation and multimode interactions in intermediate-stage Rayleigh-Taylor instability

  2. Quantification of axial alignment of the lower extremity on conventional and digital total leg radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, J.; Scharitzer, M.; Peloschek, P.; Imhof, H.; Grampp, S. [Medizinische Fakultaet der Universitaet Wien, Univ. Klinik fuer Radiodiagnostik, Abteilung Osteoradiologie, Vienna (Austria); Giurea, A. [Medizinische Fakultaet der Universitaet Wien, Univ. Klinik fuer Orthopaedie, Vienna (Austria)

    2005-01-01

    The purpose was to assess axial alignment of the lower limb using mechanical axis measurements on conventional and digital radiographs. Total-leg radiographs of 24 patients, 8 male and 16 female, with a mean age of 68.6{+-}10.2 years, were performed in a standardized anterior-posterior projection and standing position using a conventional and digital phosphor storage film screen radiography system. Knee joint angulation was assessed by measuring the angle between a line drawn from the center of the femoral head to the middle of the femoral condyles and a line drawn from the middle of the tibial condyles to the midpoint of the malleolus. On conventional leg radiographs, line drawing and angle measurement were performed manually with a transparent goniometer. Angle measurement on digital leg radiographs was performed on a PACS workstation using computer-assisted measurement software (IMPAX, AGFA-GEVAERT, Belgium). Evaluation time for both measurements was recorded. We diagnosed 14 varus and 10 valgus angulations of the knee joint. The mean individual difference between axis deviation of conventional digital leg radiographs was 0.93+0.6 (min 0 , max 2 ), the mean difference in varus angulation was 1.13{+-}0.45 (min 0.3 , max 2 ), and the mean difference in valgus angulation was 0.65{+-}0.71 (min 0 , max 2 ). Angle measurements on conventional and digital radiographs did not show any statistically significant difference. Mean time exposure was 4.9 min/patient for manual and 1.08 min/patient for computer-assisted angle measurement (P<0.001). Computer-assisted angle measurement on digital total-leg radiographs represents a reliable method with no significant angle differences compared to conventional radiographic systems and offers a significantly lower evaluation time. (orig.)

  3. CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis.

    Science.gov (United States)

    Fadell, Michael F; Gralla, Jane; Bercha, Istiaq; Stewart, Jaime R; Harned, Roger K; Ingram, James D; Miller, Angie L; Strain, John D; Weinman, Jason P

    2015-07-01

    Lumbar spondylolysis, a unilateral or bilateral fracture at pars interarticularis, is a common cause of low back pain in children. The initial imaging study in the diagnosis of lumbar spondylolysis has historically been lumbar spine radiographs; however, radiographs can be equivocal or false-negative. Definitive diagnosis can be achieved with computed tomography (CT), but its use has been limited due to the dose of ionizing radiation to the patient. By limiting the z-axis coverage to the relevant anatomy and optimizing the CT protocol, we are able to provide a definitive diagnosis of fractures of the pars interarticularis at comparable or lower radiation dose than commonly performed lumbar spine radiographs. As there is no gold standard for the diagnosis of spondylolysis besides surgery, we compared interobserver agreement and degree of confidence to determine which modality is preferable. Sixty-two patients with low back pain ages 5-18 years were assessed for the presence of spondylolyis. Forty-seven patients were evaluated by radiography and 15 patients were evaluated by limited field-of-view CT. Both radiographic and CT examinations were assessed anonymously in random order for the presence or absence of spondylolyisis by six raters. Agreement was assessed among raters using a Fleiss Kappa statistic for multiple raters. CT provided a significantly higher level of agreement among raters than radiographs (P < 0.001). The overall Kappa for rater agreement with radiographs was 0.24, 0.34 and 0.40 for 2, 3 or 4 views, respectively, and 0.88 with CT. Interobserver agreement is significantly greater using limited z-axis coverage CT when compared with radiographs. Radiologist confidence improved significantly with CT compared to radiographs regardless of the number of views.

  4. CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fadell, Michael F.; Stewart, Jaime R.; Harned, Roger K.; Ingram, James D.; Miller, Angie L.; Strain, John D.; Weinman, Jason P. [Children' s Hospital Colorado, Department of Radiology, Aurora, CO (United States); University of Colorado Hospital, Department of Radiology, Aurora, CO (United States); Gralla, Jane [University of Colorado Denver, Department of Pediatrics, Aurora, CO (United States); Bercha, Istiaq [Children' s Hospital Colorado, Department of Radiology, Aurora, CO (United States)

    2015-07-15

    Lumbar spondylolysis, a unilateral or bilateral fracture at pars interarticularis, is a common cause of low back pain in children. The initial imaging study in the diagnosis of lumbar spondylolysis has historically been lumbar spine radiographs; however, radiographs can be equivocal or false-negative. Definitive diagnosis can be achieved with computed tomography (CT), but its use has been limited due to the dose of ionizing radiation to the patient. By limiting the z-axis coverage to the relevant anatomy and optimizing the CT protocol, we are able to provide a definitive diagnosis of fractures of the pars interarticularis at comparable or lower radiation dose than commonly performed lumbar spine radiographs. As there is no gold standard for the diagnosis of spondylolysis besides surgery, we compared interobserver agreement and degree of confidence to determine which modality is preferable. Sixty-two patients with low back pain ages 5-18 years were assessed for the presence of spondylolysis. Forty-seven patients were evaluated by radiography and 15 patients were evaluated by limited field-of-view CT. Both radiographic and CT examinations were assessed anonymously in random order for the presence or absence of spondylolysis by six raters. Agreement was assessed among raters using a Fleiss Kappa statistic for multiple raters. CT provided a significantly higher level of agreement among raters than radiographs (P < 0.001). The overall Kappa for rater agreement with radiographs was 0.24, 0.34 and 0.40 for 2, 3 or 4 views, respectively, and 0.88 with CT. Interobserver agreement is significantly greater using limited z-axis coverage CT when compared with radiographs. Radiologist confidence improved significantly with CT compared to radiographs regardless of the number of views. (orig.)

  5. CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis

    International Nuclear Information System (INIS)

    Fadell, Michael F.; Stewart, Jaime R.; Harned, Roger K.; Ingram, James D.; Miller, Angie L.; Strain, John D.; Weinman, Jason P.; Gralla, Jane; Bercha, Istiaq

    2015-01-01

    Lumbar spondylolysis, a unilateral or bilateral fracture at pars interarticularis, is a common cause of low back pain in children. The initial imaging study in the diagnosis of lumbar spondylolysis has historically been lumbar spine radiographs; however, radiographs can be equivocal or false-negative. Definitive diagnosis can be achieved with computed tomography (CT), but its use has been limited due to the dose of ionizing radiation to the patient. By limiting the z-axis coverage to the relevant anatomy and optimizing the CT protocol, we are able to provide a definitive diagnosis of fractures of the pars interarticularis at comparable or lower radiation dose than commonly performed lumbar spine radiographs. As there is no gold standard for the diagnosis of spondylolysis besides surgery, we compared interobserver agreement and degree of confidence to determine which modality is preferable. Sixty-two patients with low back pain ages 5-18 years were assessed for the presence of spondylolysis. Forty-seven patients were evaluated by radiography and 15 patients were evaluated by limited field-of-view CT. Both radiographic and CT examinations were assessed anonymously in random order for the presence or absence of spondylolysis by six raters. Agreement was assessed among raters using a Fleiss Kappa statistic for multiple raters. CT provided a significantly higher level of agreement among raters than radiographs (P < 0.001). The overall Kappa for rater agreement with radiographs was 0.24, 0.34 and 0.40 for 2, 3 or 4 views, respectively, and 0.88 with CT. Interobserver agreement is significantly greater using limited z-axis coverage CT when compared with radiographs. Radiologist confidence improved significantly with CT compared to radiographs regardless of the number of views. (orig.)

  6. Hydrodynamic Limit of Multiple SLE

    Science.gov (United States)

    Hotta, Ikkei; Katori, Makoto

    2018-04-01

    Recently del Monaco and Schleißinger addressed an interesting problem whether one can take the limit of multiple Schramm-Loewner evolution (SLE) as the number of slits N goes to infinity. When the N slits grow from points on the real line R in a simultaneous way and go to infinity within the upper half plane H, an ordinary differential equation describing time evolution of the conformal map g_t(z) was derived in the N → ∞ limit, which is coupled with a complex Burgers equation in the inviscid limit. It is well known that the complex Burgers equation governs the hydrodynamic limit of the Dyson model defined on R studied in random matrix theory, and when all particles start from the origin, the solution of this Burgers equation is given by the Stieltjes transformation of the measure which follows a time-dependent version of Wigner's semicircle law. In the present paper, first we study the hydrodynamic limit of the multiple SLE in the case that all slits start from the origin. We show that the time-dependent version of Wigner's semicircle law determines the time evolution of the SLE hull, K_t \\subset H\\cup R, in this hydrodynamic limit. Next we consider the situation such that a half number of the slits start from a>0 and another half of slits start from -a < 0, and determine the multiple SLE in the hydrodynamic limit. After reporting these exact solutions, we will discuss the universal long-term behavior of the multiple SLE and its hull K_t in the hydrodynamic limit.

  7. Propulsion and hydrodynamic particle transport of magnetically twisted colloidal ribbons

    Science.gov (United States)

    Massana-Cid, Helena; Martinez-Pedrero, Fernando; Navarro-Argemí, Eloy; Pagonabarraga, Ignacio; Tierno, Pietro

    2017-10-01

    We describe a method to trap, transport and release microscopic particles in a viscous fluid using the hydrodynamic flow field generated by a magnetically propelled colloidal ribbon. The ribbon is composed of ferromagnetic microellipsoids that arrange with their long axis parallel to each other, a configuration that is energetically favorable due to their permanent magnetic moments. We use an external precessing magnetic field to torque the anisotropic particles forming the ribbon, and to induce propulsion of the entire structure due to the hydrodynamic coupling with the close substrate. The propulsion speed of the ribbon can be controlled by varying the driving frequency, or the amplitude of the precessing field. The latter parameter is also used to reduce the average inter particle distance and to induce the twisting of the ribbon due to the increase in the attraction between the rotating ellipsoids. Furthermore, non magnetic particles are attracted or repelled with the hydrodynamic flow field generated by the propelling ribbon. The proposed method may be used in channel free microfluidic applications, where the precise trapping and transport of functionalized particles via non invasive magnetic fields is required.

  8. Final Report. Hydrodynamics by high-energy-density plasma flow and hydrodynamics and radiative hydrodynamics with astrophysical application

    International Nuclear Information System (INIS)

    R Paul Drake

    2004-01-01

    OAK-B135 This is the final report from the project Hydrodynamics by High-Energy-Density Plasma Flow and Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications. This project supported a group at the University of Michigan in the invention, design, performance, and analysis of experiments using high-energy-density research facilities. The experiments explored compressible nonlinear hydrodynamics, in particular at decelerating interfaces, and the radiation hydrodynamics of strong shock waves. It has application to supernovae, astrophysical jets, shock-cloud interactions, and radiative shock waves

  9. Radiographic findings of Proteus Syndrome

    Directory of Open Access Journals (Sweden)

    Nishant Mukesh Gandhi, MD

    2014-01-01

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

  10. Radiographic findings of Proteus Syndrome

    Science.gov (United States)

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

    2015-01-01

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

  11. Radiographic testing in concrete structures

    International Nuclear Information System (INIS)

    Oliveira, D. de

    1987-01-01

    The radiographic testing done in concrete structures is used to analyse the homogeneity, position and corrosion of armatures and to detect discontinuity in the concrete such as: gaps, cracks and segregations. This work develops a Image quality Indicator (IQI) with an adequated sensibility to detect discontinuites based on BS4408 norm. (E.G.) [pt

  12. Radiographic assessment of endodontic working length

    OpenAIRE

    Osama S Alothmani; Lara T Friedlander; Nicholas P Chandler

    2013-01-01

    The use of radiographs for working length determination is usual practice in endodontics. Exposing radiographs following the principles of the paralleling technique allows more accurate length determination compared to the bisecting-angle method. However, it has been reported that up to 28.5% of cases can have the file tip extending beyond the confines of the root canals despite an acceptable radiographic appearance. The accuracy of radiographic working length determination could be affected ...

  13. Hydrodynamics from Landau initial conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Abhisek [University of Tennessee, Knoxville (UTK); Gerhard, Jochen [Frankfurt Institute for Advanced Studies (FIAS), Germany; Torrieri, Giorgio [Universidade Estadual de Campinas, Instituto de Física " Gleb Wataghin" (IFGW), Sao Paulo, Brazil; Read jr, Kenneth F. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Wong, Cheuk-Yin [ORNL

    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

  14. Hydrodynamic simulations of expanding shells

    Czech Academy of Sciences Publication Activity Database

    Wünsch, Richard; Palouš, Jan; Ehlerová, Soňa

    2004-01-01

    Roč. 289, 3-4 (2004), s. 35-36 ISSN 0004-640X. [From observation to self-consistent modelling of the ISM in galaxies. Porto, 03.09.2002-05.09.2002] R&D Projects: GA AV ČR KSK1048102 Keywords : hydrodynamic simulations * ISM * star formation Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.597, year: 2004

  15. Hydrodynamics of spatially ordered superfluids

    Energy Technology Data Exchange (ETDEWEB)

    Stoof, H.T. [Institute for Theoretical Physics, University of Utrecht, Princetonplein 5, P.O. Box 80.006, 3508 TA Utrecht (The Netherlands); Mullen, K. [Department of Physics, University of Oklahoma, Norman, Oklahoma 73019-0225 (United States); Wallin, M. [Department of Theoretical Physics, Royal Institute of Technology, S-100 44 Stockholm (Sweden); Girvin, S.M. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States)

    1996-03-01

    We derive the hydrodynamic equations for the supersolid and superhexatic phases of a neutral two-dimensional Bose fluid. We find, assuming that the normal part of the fluid is clamped to an underlying substrate, that both phases can sustain third-sound modes and that in the supersolid phase there are additional modes due to the superfluid motion of point defects (vacancies and interstitials). {copyright} {ital 1996 The American Physical Society.}

  16. Laser driven hydrodynamic instability experiments

    International Nuclear Information System (INIS)

    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.

    1993-01-01

    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

  17. 21 CFR 892.1840 - Radiographic film.

    Science.gov (United States)

    2010-04-01

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

  18. Chest radiographic findings in Human Immunodeficiency Virus ...

    African Journals Online (AJOL)

    Patients had postero-anterior (PA) chest radiographs done in full inspiration, with a Roentgen 301 radiographic machine (GEC Medical) using the following factors; KVp = 65, focus-film distance = 150cm and 12 – 15mAs. A total of 308 confirmed HIV- positive patients had chest radiographic examinations. Ninety-nine ...

  19. Hydrodynamic instabilities in miscible fluids

    Science.gov (United States)

    Truzzolillo, Domenico; Cipelletti, Luca

    2018-01-01

    Hydrodynamic instabilities in miscible fluids are ubiquitous, from natural phenomena up to geological scales, to industrial and technological applications, where they represent the only way to control and promote mixing at low Reynolds numbers, well below the transition from laminar to turbulent flow. As for immiscible fluids, the onset of hydrodynamic instabilities in miscible fluids is directly related to the physics of their interfaces. The focus of this review is therefore on the general mechanisms driving the growth of disturbances at the boundary between miscible fluids, under a variety of forcing conditions. In the absence of a regularizing mechanism, these disturbances would grow indefinitely. For immiscible fluids, interfacial tension provides such a regularizing mechanism, because of the energy cost associated to the creation of new interface by a growing disturbance. For miscible fluids, however, the very existence of interfacial stresses that mimic an effective surface tension is debated. Other mechanisms, however, may also be relevant, such as viscous dissipation. We shall review the stabilizing mechanisms that control the most common hydrodynamic instabilities, highlighting those cases for which the lack of an effective interfacial tension poses deep conceptual problems in the mathematical formulation of a linear stability analysis. Finally, we provide a short overview on the ongoing research on the effective, out of equilibrium interfacial tension between miscible fluids.

  20. Hydrodynamic instabilities in miscible fluids.

    Science.gov (United States)

    Truzzolillo, Domenico; Cipelletti, Luca

    2018-01-24

    Hydrodynamic instabilities in miscible fluids are ubiquitous, from natural phenomena up to geological scales, to industrial and technological applications, where they represent the only way to control and promote mixing at low Reynolds numbers, well below the transition from laminar to turbulent flow. As for immiscible fluids, the onset of hydrodynamic instabilities in miscible fluids is directly related to the physics of their interfaces. The focus of this review is therefore on the general mechanisms driving the growth of disturbances at the boundary between miscible fluids, under a variety of forcing conditions. In the absence of a regularizing mechanism, these disturbances would grow indefinitely. For immiscible fluids, interfacial tension provides such a regularizing mechanism, because of the energy cost associated to the creation of new interface by a growing disturbance. For miscible fluids, however, the very existence of interfacial stresses that mimic an effective surface tension is debated. Other mechanisms, however, may also be relevant, such as viscous dissipation. We shall review the stabilizing mechanisms that control the most common hydrodynamic instabilities, highlighting those cases for which the lack of an effective interfacial tension poses deep conceptual problems in the mathematical formulation of a linear stability analysis. Finally, we provide a short overview on the ongoing research on the effective, out of equilibrium interfacial tension between miscible fluids.

  1. Particle hydrodynamics with tessellation techniques

    Science.gov (United States)

    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.

  2. Numerical Hydrodynamics in Special Relativity.

    Science.gov (United States)

    Martí, José Maria; Müller, Ewald

    2003-01-01

    This review is concerned with a discussion of numerical methods for the solution of the equations of special relativistic hydrodynamics (SRHD). Particular emphasis is put on a comprehensive review of the application of high-resolution shock-capturing methods in SRHD. Results of a set of demanding test bench simulations obtained with different numerical SRHD methods are compared. Three applications (astrophysical jets, gamma-ray bursts and heavy ion collisions) of relativistic flows are discussed. An evaluation of various SRHD methods is presented, and future developments in SRHD are analyzed involving extension to general relativistic hydrodynamics and relativistic magneto-hydrodynamics. The review further provides FORTRAN programs to compute the exact solution of a 1D relativistic Riemann problem with zero and nonzero tangential velocities, and to simulate 1D relativistic flows in Cartesian Eulerian coordinates using the exact SRHD Riemann solver and PPM reconstruction. Supplementary material is available for this article at 10.12942/lrr-2003-7 and is accessible for authorized users.

  3. Radiographic anatomy of the proximal femur: femoral neck fracture vs. transtrochanteric fracture

    Directory of Open Access Journals (Sweden)

    Ana Lecia Carneiro Leão de Araújo Lima

    Full Text Available ABSTRACT OBJECTIVE: To evaluate the correlation between radiographic parameters of the proximal femur with femoral neck fractures or transtrochanteric fractures. METHODS: Cervicodiaphyseal angle (CDA, femoral neck width (FNW, hip axis length (HAL, and acetabular tear drop distance (ATD were analyzed in 30 pelvis anteroposterior view X-rays of patients with femoral neck fractures (n = 15 and transtrochanteric fractures (n = 15. The analysis was performed by comparing the results of the X-rays with femoral neck fractures and with transtrochanteric fractures. RESULTS: No statistically significant differences between samples were observed. CONCLUSION: There was no correlation between radiographic parameters evaluated and specific occurrence of femoral neck fractures or transtrochanteric fractures.

  4. Assessment of Radiographic Image Quality by Visual Examination of Neutron Radiographs of the Calibration Fuel Pin

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    Up till now no reliable radiographic image quality standards exist for neutron radiography of nuclear reactor fuel. Under the Euratoro Neutron Radiography Working Group (NRWG) Test Program neutron radiographs were produced at different neutron radiography facilities within the European Community...... of a calibration fuel pin. The radiographs were made by the direct, transfer and tracketch methods using different film recording materials. These neutron radiographs of the calibration fuel pin were used for the assessement of radiographic image quality. This was done by visual examination of the radiographs...... and assessing their radiographic image quality on an arbitrary scale....

  5. Pulmonary edema: radiographic differential diagnosis

    International Nuclear Information System (INIS)

    Yoo, Dong Soo; Choi, Young Hi; Kim, Seung Cheol; An, Ji Hyun; Lee, Jee Young; Park, Hee Hong

    1997-01-01

    To evaluate the feasibility of using chest radiography to differentiate between three different etiologies of pulmonary edema. Plain chest radiographs of 77 patients, who were clinically confirmed as having pulmonary edema, were retrospectively reviewed. The patients were classified into three groups : group 1 (cardiogenic edema : n = 35), group 2 (renal pulmonary edema : n = 16) and group 3 (permeability edema : n = 26). We analyzed the radiologic findings of air bronchogram, heart size, peribronchial cuffing, septal line, pleural effusion, vascular pedicle width, pulmonary blood flow distribution and distribution of pulmonary edema. In a search for radiologic findings which would help in the differentiation of these three etiologies, each finding was assessed. Cardiogenic and renal pulmonary edema showed overlapping radiologic findings, except for pulmonary blood flow distribution. In cardiogenic pulmonary edema (n=35), cardiomegaly (n=29), peribronchial cuffing (n=29), inverted pulmonary blood flow distribution (n=21) and basal distribution of edema (n=20) were common. In renal pulmonary edema (n=16), cardiomegaly (n=15), balanced blood flow distribution (n=12), and central (n=9) or basal distribution of edema (n=7) were common. Permeability edema (n=26) showed different findings. Air bronchogram (n=25), normal blood flow distribution (n=14) and peripheral distribution of edema (n=21) were frequent findings, while cardiomegaly (n=7), peribronchial cuffing (n=7) and septal line (n=5) were observed in only a few cases. On plain chest radiograph, permeability edema can be differentiated from cardiogenic or renal pulmonary edema. The radiographic findings which most reliably differentiated these two etiologies were air bronchogram, distribution of pulmonary edema, peribronchial cuffing and heart size. Only blood flow distribution was useful for radiographic differentiation of cardiogenic and renal edema

  6. Occupational health and the radiographer

    International Nuclear Information System (INIS)

    Stronach, T.

    1990-01-01

    This paper identifies some of the occupational health hazards faced by radiographers in the hospital environment. There has been very little work done in this area in the past, and as the subject is so large this paper can do little other than raise some of the issues . The hazards addressed include: radiation, ergonomics, chemical, environmental, biological, occupational injury and accident, stress. 14 refs., 2 figs

  7. A Radiographic Study of Odontoma

    International Nuclear Information System (INIS)

    Lee, Kyung Ho; Choi, Karp Shik

    1998-01-01

    The purpose of this study was to obtain information on the clinical and radiographic features of the odontomas in the jaws. For this study, the authors examined and analyzed the clinical records and radiographs of 119 patients who had lesion of odontoma diagnosed by clinical and radiographic examinations. The obtained results were as follows ; 1. Odontoma occurred the most frequently in the 2nd decade (45.4%) and occurred more frequently in males (60.5%) than in females (39.5%). 2. The most common clinical symptom was the delayed eruption of the teeth (34.2%). 3. The type of lesions was mainly observed as compound odontoma (80.8%), and internal pattern of the complex odontoma was unevenly radiopaque (73.9%). 4. The compound odontoma frequently occurred in anterior portion of the maxilla (57.7%) and mandible (30.9%), and complex odontoma frequently occurred in anterior portion of maxilla (34.8%) and posterior portion of mandible (30.5%). 5. The effects on adjacent teeth were impaction of teeth (71.7%) and prolonged retention of deciduous teeth (31.7%). 6. The impaction of the teeth occurred in anterior portion of maxilla (44.2%) amd mandible (19.2%), but root resorption of the adjacent teeth were not seen. 7. The boundary to adjacent structure was well-defined , the lesions appear as radiopaque mass with radiolucent rim.

  8. A Radiographic Study of Odontoma

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Ho; Choi, Karp Shik [Dept. of Dental Radiology, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of)

    1998-02-15

    The purpose of this study was to obtain information on the clinical and radiographic features of the odontomas in the jaws. For this study, the authors examined and analyzed the clinical records and radiographs of 119 patients who had lesion of odontoma diagnosed by clinical and radiographic examinations. The obtained results were as follows: 1. Odontoma occurred the most frequently in the 2nd decade (45.4%) and occurred more frequently in males (60.5%) than in females (39.5%). 2. The most common clinical symptom was the delayed eruption of the teeth (34.2%). 3. The type of lesions was mainly observed as compound odontoma (80.8%), and internal pattern of the complex odontoma was unevenly radiopaque (73.9%). 4. The compound odontoma frequently occurred in anterior portion of the maxilla (57.7%) and mandible (30.9%), and complex odontoma frequently occurred in anterior portion of maxilla (34.8%) and posterior portion of mandible (30.5%). 5. The effects on adjacent teeth were impaction of teeth (71.7%) and prolonged retention of deciduous teeth (31.7%). 6. The impaction of the teeth occurred in anterior portion of maxilla (44.2%) amd mandible (19.2%), but root resorption of the adjacent teeth were not seen. 7. The boundary to adjacent structure was well-defined , the lesions appear as radiopaque mass with radiolucent rim.

  9. Automating the radiographic NDT process

    International Nuclear Information System (INIS)

    Aman, J.K.

    1986-01-01

    Automation, the removal of the human element in inspection, has not been generally applied to film radiographic NDT. The justication for automating is not only productivity but also reliability of results. Film remains in the automated system of the future because of its extremely high image content, approximately 8 x 10 9 bits per 14 x 17. The equivalent to 2200 computer floppy discs. Parts handling systems and robotics applied for manufacturing and some NDT modalities, should now be applied to film radiographic NDT systems. Automatic film handling can be achieved with the daylight NDT film handling system. Automatic film processing is becoming the standard in industry and can be coupled to the daylight system. Robots offer the opportunity to automate fully the exposure step. Finally, computer aided interpretation appears on the horizon. A unit which laser scans a 14 x 17 (inch) film in 6 - 8 seconds can digitize film information for further manipulation and possible automatic interrogations (computer aided interpretation). The system called FDRS (for Film Digital Radiography System) is moving toward 50 micron (*approx* 16 lines/mm) resolution. This is believed to meet the need of the majority of image content needs. We expect the automated system to appear first in parts (modules) as certain operations are automated. The future will see it all come together in an automated film radiographic NDT system (author) [pt

  10. A radiographic study of cementoma

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral Radiology, Division of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    1986-11-15

    This study was undertaken to document and better define this condition to help clarify this clinical and radiographic appearances by analysis of clinical and radiographic features of cementoma. A study was made of a series of 104 cases with cementoma. This investigation of cementoma revealed the following features: 1. The female occurred in 73% of periapical cemental dysplasia and benign cementoblastoma, and 80% of cementifying fibroma. 2. 40% of periapical cemental dysplasia occurred in the fifth decades, and 73% of benign cementoblastoma during the second and third decades, while there was no age predilection in the cementifying fibroma. 3. 63% of periapical cemental dysplasia occurred in the mandibular anterior region. 91% of benign cementoblastom a and 80% of cementifying fibroma occurred in the mandibular premolar and/or molar region. 4. There were no cases complaining the associated clinical signs and subjective symptoms in the periapical cemental dysplasia, however the patient complained the pain in 36% of benign cementoblastoma and 40% of cementifying fibroma. 5. There were no cases expanding the cortical plates in the periapical cemental dysplasia, however 73% of benign cementoblastoma and all of 5 cases of cementifying fibroma showed the expansion of cortical plates. 6. Several radiographic features of the periapical cemental dysplasia were shown. a. 29% of the cases had multiple lesion. b. 53% of the cases were in mature stage. c. During the osteolytic stage, the alveolar lamina dura was lost in 89% of the cases.

  11. Entropy-limited hydrodynamics: a novel approach to relativistic hydrodynamics

    Science.gov (United States)

    Guercilena, Federico; Radice, David; Rezzolla, Luciano

    2017-07-01

    We present entropy-limited hydrodynamics (ELH): a new approach for the computation of numerical fluxes arising in the discretization of hyperbolic equations in conservation form. ELH is based on the hybridisation of an unfiltered high-order scheme with the first-order Lax-Friedrichs method. The activation of the low-order part of the scheme is driven by a measure of the locally generated entropy inspired by the artificial-viscosity method proposed by Guermond et al. (J. Comput. Phys. 230(11):4248-4267, 2011, doi: 10.1016/j.jcp.2010.11.043). Here, we present ELH in the context of high-order finite-differencing methods and of the equations of general-relativistic hydrodynamics. We study the performance of ELH in a series of classical astrophysical tests in general relativity involving isolated, rotating and nonrotating neutron stars, and including a case of gravitational collapse to black hole. We present a detailed comparison of ELH with the fifth-order monotonicity preserving method MP5 (Suresh and Huynh in J. Comput. Phys. 136(1):83-99, 1997, doi: 10.1006/jcph.1997.5745), one of the most common high-order schemes currently employed in numerical-relativity simulations. We find that ELH achieves comparable and, in many of the cases studied here, better accuracy than more traditional methods at a fraction of the computational cost (up to {˜}50% speedup). Given its accuracy and its simplicity of implementation, ELH is a promising framework for the development of new special- and general-relativistic hydrodynamics codes well adapted for massively parallel supercomputers.

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

    Directory of Open Access Journals (Sweden)

    Madeleine Willegger

    Full Text Available 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.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.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%: 0.966-0.989 and for the

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

    Science.gov (United States)

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

    2016-01-01

    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. 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. 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%: 0.966-0.989) and for the STTA (ICC: 0

  14. Interactive radiographic image retrieval system.

    Science.gov (United States)

    Kundu, Malay Kumar; Chowdhury, Manish; Das, Sudeb

    2017-02-01

    Content based medical image retrieval (CBMIR) systems enable fast diagnosis through quantitative assessment of the visual information and is an active research topic over the past few decades. Most of the state-of-the-art CBMIR systems suffer from various problems: computationally expensive due to the usage of high dimensional feature vectors and complex classifier/clustering schemes. Inability to properly handle the "semantic gap" and the high intra-class versus inter-class variability problem of the medical image database (like radiographic image database). This yields an exigent demand for developing highly effective and computationally efficient retrieval system. We propose a novel interactive two-stage CBMIR system for diverse collection of medical radiographic images. Initially, Pulse Coupled Neural Network based shape features are used to find out the most probable (similar) image classes using a novel "similarity positional score" mechanism. This is followed by retrieval using Non-subsampled Contourlet Transform based texture features considering only the images of the pre-identified classes. Maximal information compression index is used for unsupervised feature selection to achieve better results. To reduce the semantic gap problem, the proposed system uses a novel fuzzy index based relevance feedback mechanism by incorporating subjectivity of human perception in an analytic manner. Extensive experiments were carried out to evaluate the effectiveness of the proposed CBMIR system on a subset of Image Retrieval in Medical Applications (IRMA)-2009 database consisting of 10,902 labeled radiographic images of 57 different modalities. We obtained overall average precision of around 98% after only 2-3 iterations of relevance feedback mechanism. We assessed the results by comparisons with some of the state-of-the-art CBMIR systems for radiographic images. Unlike most of the existing CBMIR systems, in the proposed two-stage hierarchical framework, main importance

  15. Gut Microbiota-brain Axis.

    Science.gov (United States)

    Wang, Hong-Xing; Wang, Yu-Ping

    2016-10-05

    To systematically review the updated information about the gut microbiota-brain axis. 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". All relevant articles on gut microbiota and gut-brain axis were included and carefully reviewed, with no limitation of study design. 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. 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.

  16. A new digital tool for radiographic bone level measurements in longitudinal studies.

    Science.gov (United States)

    Preus, Hans R; Torgersen, Gerald Ruiner; Koldsland, Odd Carsten; Hansen, Bjørn Frode; Aass, Anne Merete; Larheim, Tore Arne; Sandvik, Leiv

    2015-09-08

    The reproducibility of measurements on radiographs is influenced by the techniques by which the images as well as the measurements are obtained. Thus, bias resulting from errors in the image and/or image examinations at two points in time may result in wrongful registrations of true biological or pathological changes. The aim of the present study was to propose and evaluate an indirect radiological examination technique, by which bias, when measuring radiographic bone level, could be substantially reduced as compared to the technique using direct mm measurements. A plugin to ImageJ was designed to reduce bias when measuring bone loss on radiographic images. In human dry mandibles, radiographic images of 20 teeth were obtained parallel with the tooth axis (alpha = 0) and at an angle of 30° deviation. The direct technique of measuring radiographic bone level (RBL) and the indirect, length-adjusted RBL were registered by four researchers in a double blinded fashion. When mean RBL measured at 0° angle was 7.0 mm, the corresponding mean RBL measured at 30° angle was 7.8 mm, signifying an 11.4% increase (p = 0.032), whereas the mean length-adjusted RBL increased by 0.6% (p = 0.9). This study showed that the use of the original, direct technique (ImageJ) resulted in markedly biased radiographic bone level at 30° angle, while the proposed indirect length-adjusted technique (ImageJ plugin) did not.

  17. Gut Microbiota-brain Axis

    OpenAIRE

    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 s...

  18. DARHT Axis II Cathode 16 (S/N 22) History as Recorded in the Historian and Shot Data Databases

    Energy Technology Data Exchange (ETDEWEB)

    Smith, H. Vernon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Barraza, Juan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harrison, James F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Jeffrey B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nassiri, Homa [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ekdahl, Jr., Carl A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-10

    Long DARHT II injector cathode operating lifetimes are desirable for flash radiography of hydrodynamic tests at the dual-axis radiographic hydrotest facility (DARHT). The specification for cathode operating lifetime given to Spectra-Mat in the purchase orders for the 311X-M cathodes is ≥ 1000 hours at full operating temperature (~1120 oC). Of the five most-recent cathodes operated on DARHT II, only two have met this specification. It is desirable to have cathodes lifetimes considerably longer than the specified 1000 hours. In this report we present the thermal and vacuum history of cathode 16 (serial no. [S/N] 22), a 311X-M cathode, as recorded in the historian database and the shot data database. The hope is that by examining this history we can identify the parameter (or parameters) that are limiting the DARHT II 311X-M cathode lifetimes. This is the fifth in a series of 5 DARHT Tech Notes in which recent cathode thermal and vacuum histories are examined. The other tech notes in this series are DARHT Tech Notes Nos. 501 (cathode 12, S/N 15), 502 (cathode 13, S/N 19), 503 (cathode 14, S/N 20), and 504 (cathode 15, S/N 21). In DARHT Tech Note No. 506 we will compare the recorded thermal and vacuum histories of cathodes 12-16 and attempt to understand the cathode lifetime limitations based on the stored cathode data presented in DARHT Tech Notes 501-505 and other relevant information.

  19. Disruptive Innovation in Numerical Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Waltz, Jacob I. [Los Alamos National Laboratory

    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.

  20. Numerical Hydrodynamics in General Relativity

    Directory of Open Access Journals (Sweden)

    Font José A.

    2000-05-01

    Full Text Available The current status of numerical solutions for the equations of ideal general relativistic hydrodynamics is reviewed. Different formulations of the equations are presented, with special mention of conservative and hyperbolic formulations well-adapted to advanced numerical methods. A representative sample of available numerical schemes is discussed and particular emphasis is paid to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. A comprehensive summary of relevant astrophysical simulations in strong gravitational fields, including gravitational collapse, accretion onto black holes and evolution of neutron stars, is also presented.

  1. Laser driven hydrodynamic instability experiments

    International Nuclear Information System (INIS)

    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.

    1992-01-01

    We have conducted an extensive series of experiments 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; multimode foils allow an assessment of the degree of mode coupling; and surface-finish experiments allow a measurement of the evolution of a broad spectrum of random initial modes. Experimental results and comparisons with theory and simulations are presented

  2. Hydrodynamics and stellar winds an introduction

    CERN Document Server

    Maciel, Walter J

    2014-01-01

    Stellar winds are a common phenomenon in the life of stars, from the dwarfs like the Sun to the red giants and hot supergiants, constituting one of the basic aspects of modern astrophysics. Stellar winds are a hydrodynamic phenomenon in which circumstellar gases expand towards the interstellar medium. This book presents an elementary introduction to the fundamentals of hydrodynamics with an application to the study of stellar winds. The principles of hydrodynamics have many other applications, so that the book can be used as an introduction to hydrodynamics for students of physics, astrophysics and other related areas.

  3. The future for the radiographer

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder

    that it is not the patient who must comply with technology, but the other way around. My point is that if reporting radiographers merely focuses on technology then they leave behind the very core of radiography, namely radiography as a caring practice, which would leave care in the hands of less educated personnel. So I....... We believe that it is time that we take responsibility for this important part of radiography and systematically teaching it in the context where it unfolds instead of insinuating that care is learned best elsewhere. I believe and hope that especially the Nordic countries could learn from each other...

  4. Fluctuating hydrodynamics for ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Lazaridis, Konstantinos [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States); Wickham, Logan [Department of Computer Science, Washington State University, Richland, 99354 (United States); Voulgarakis, Nikolaos, E-mail: n.voulgarakis@wsu.edu [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States)

    2017-04-25

    We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau–Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids. - Highlights: • A new fluctuating hydrodynamics method for ionic liquids. • Description of ionic liquid morphology in bulk and near electrified surfaces. • Direct comparison with experimental measurements.

  5. Hydrodynamic dispersion within porous biofilms.

    Science.gov (United States)

    Davit, Y; Byrne, H; Osborne, J; Pitt-Francis, J; Gavaghan, D; Quintard, M

    2013-01-01

    Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate various aspects of cell behavior by controlling nutrient supply, evacuation of waste products, and permeation of antimicrobial agents. This study presents multiscale analysis of solute transport in these porous biofilms. We start our analysis with a channel-scale description of mass transport and use the method of volume averaging to derive a set of homogenized equations at the biofilm-scale in the case where the width of the channels is significantly smaller than the thickness of the biofilm. We show that solute transport may be described via two coupled partial differential equations or telegrapher's equations for the averaged concentrations. These models are particularly relevant for chemicals, such as some antimicrobial agents, that penetrate cell clusters very slowly. In most cases, especially for nutrients, solute penetration is faster, and transport can be described via an advection-dispersion equation. In this simpler case, the effective diffusion is characterized by a second-order tensor whose components depend on (1) the topology of the channels' network; (2) the solute's diffusion coefficients in the fluid and the cell clusters; (3) hydrodynamic dispersion effects; and (4) an additional dispersion term intrinsic to the two-phase configuration. Although solute transport in biofilms is commonly thought to be diffusion dominated, this analysis shows that hydrodynamic dispersion effects may significantly contribute to transport.

  6. Invariant description of solutions of hydrodynamic-type systems in hodograph space: hydrodynamic surfaces

    International Nuclear Information System (INIS)

    Ferapontov, E.V.

    2002-01-01

    Hydrodynamic surfaces are solutions of hydrodynamic-type systems viewed as non-parametrized submanifolds of the hodograph space. We propose an invariant differential-geometric characterization of hydrodynamic surfaces by expressing the curvature form of the characteristic web in terms of the reciprocal invariants. (author)

  7. Gastric tumors on chest radiographs

    International Nuclear Information System (INIS)

    Tamura, Shozo; Kawanami, Takashi; Russell, W.J.

    1978-04-01

    Gastric neoplasms of three patients protruded into their gas-containing fornices and were first visualized on plain chest radiographs. Endoscopy and/or surgery confirmed these to be a polyp, a leiomyoma, and an adenocarcinoma. The polyp, 1.3 cm in diameter, was the smallest of these three, but smaller lesions may be detectable under suitable conditions. Adequate technique and positioning, sufficiently large lesions in the upper portion of the stomach, a central beam tangential to the tumor, sufficient gas in the stomach, and careful scrutiny by the observer are required. Lesions may be more readily visualized during chest radiography when oral sodium bicarbonate is used to distend the stomach. In chest radiography, exposure limited to the lung fields has been advocated for economy and dose reduction. However, too small an exposure field may result in loss of information potentially beneficial to the patient. Using the smaller of two popular film sizes (35 x 43 cm and 35 x 35 cm), the saving in surface and bone marrow doses is negligible, and the saving in gonad dose may be nil over that when shielding is used. The interest of the observer may be absorbed by a concomitant cardiac or pulmonary lesion. Careful scrutiny of the entire radiograph is therefore essential. (author)

  8. Digital processing of radiographic images

    Science.gov (United States)

    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.

  9. Prognostic radiographic aspects of spondylolisthesis

    Energy Technology Data Exchange (ETDEWEB)

    Saraste, H.; Brostroem, L.A.; Aparisi, T.

    1984-01-01

    A series of 202 patients (133 men, 69 women) with lumbar spondylolysis were examined radiographically on two occasions, first at the time of diagnosis and later at a follow-up, after an observation period of 20 years or more. The films from patients in groups without and with moderate and severe olisthesis were evaluated with respect to variables describing lumbosacral lordosis, wedging of the spondylolytic vertebra, lengths of the transverse processes and iliolumbar ligaments, disk height, progression of slipping, and influence on measured olisthesis of lumbar spine flexion and extension at the radiographic examination. The evaluation was made with special attention to possible signs which could be predictive for the prognosis of vertebral slipping. Progression of slipping did not differ between patients diagnosed as adults or adolescents. Reduction of disk height was correlated to the degree of slipping present at the initial examination and to the progression of olisthesis. Flexion and extension of the lumbar spine did not modify the degree of olisthesis. Data concerning the lengths of the transverse processes and the iliolumbar ligaments, and lumbar lordosis, cannot be used for prognostic purposes. The lumbar index reflecting the degree of wedge deformity of the spondylolytic vertebra was shown to be the only variable of prognostic value for the development of vertebral slipping.

  10. Prognostic radiographic aspects of spondylolisthesis

    International Nuclear Information System (INIS)

    Saraste, H.; Brostroem, L.A.; Aparisi, T.

    1984-01-01

    A series of 202 patients (133 men, 69 women) with lumbar spondylolysis were examined radiographically on two occasions, first at the time of diagnosis and later at a follow-up, after an observation period of 20 years or more. The films frompatients in groups without and with moderate and severe olisthesis were evaluated with respect to variables describing lumbosacral lordosis, wedging of the spondylolytic vertebra, lengths of the transverse processes and iliolumbar ligaments, disk height, progression of slipping, and influence on measured olisthesis of lumbar spine flexion and extension at the radiographic examination. The evaluation was made with special attention to possible signs which could be predictive for the prognosis of vertebral slipping. Progression of slipping did not differ between patients diagnosed as adults or adolescents. Reduction of disk height was correlated to the degree of slipping present at the initial examination and to the progression of olisthesis. Flexion and extension of the lumbar spine did not modify the degree of olisthesis. Data concerning the lengths of the transverse processes and the iliolumbar ligaments, and lumbar lordosis, cannot be used for prognostic purposes. The lumbar index reflecting the degree of wedge deformity of the spondylolytic vertebra was shown to be the only variable of prognostic value for the development of vertebral slipping. (orig.)

  11. Total elbow arthroplasty: a radiographic outcome study

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xue Susan [University of Washington, Department of Radiology, Box 357115, Seattle, WA (United States); Petscavage-Thomas, Jonelle M. [Penn State Hershey Medical Center, Department of Radiology, Hershey, PA (United States); Ha, Alice S. [University of Washington, Department of Radiology, Box 354755, Seattle, WA (United States)

    2016-06-15

    Total elbow arthroplasty (TEA) is becoming a popular alternative to arthrodesis for patients with end-stage elbow arthrosis and comminuted distal humeral fractures. Prior outcome studies have primarily focused on surgical findings. Our purpose is to determine the radiographic outcome of TEA and to correlate with clinical symptoms such as pain. This is an IRB-approved retrospective review from 2005 to 2015 of all patients with semiconstrained TEA. All available elbow radiographs and clinical data were reviewed. Data analysis included descriptive statistics and Kaplan-Meier survival curves for radiographic and clinical survival. A total of 104 total elbow arthroplasties in 102 patients were reviewed; 75 % were in women and the mean patient age was 63.1 years. Mean radiographic follow-up was 826 days with average of four radiographs per patient. Seventy TEAs (67 %) developed radiographic complications, including heterotopic ossification (48 %), perihardware lucency (27 %), periprosthetic fracture (23 %), hardware subluxation/dislocation (7 %), polyethylene wear (3 %), and hardware fracture/dislodgement (3 %); 56 patients (55 %) developed symptoms of elbow pain or instability and 30 patients (30 %) underwent at least one reoperation. In patients with radiographic complications, 66 % developed elbow pain, compared to 19 % of patients with no radiologic complications (p = 0.001). Of the patients with radiographic complications, 39 % had at least one additional surgery compared to 0 % of patients without radiographic complications (p = 0.056). Radiographic complications are common in patients after total elbow arthroplasty. There is a strong positive association between post-operative radiographic findings and clinical outcome. Knowledge of common postoperative radiographic findings is important for the practicing radiologist. (orig.)

  12. A radiographic analysis of implant component misfit.

    LENUS (Irish Health Repository)

    Sharkey, Seamus

    2011-07-01

    Radiographs are commonly used to assess the fit of implant components, but there is no clear agreement on the amount of misfit that can be detected by this method. This study investigated the effect of gap size and the relative angle at which a radiograph was taken on the detection of component misfit. Different types of implant connections (internal or external) and radiographic modalities (film or digital) were assessed.

  13. Radiation protection - radiographer's role and responsibilities

    International Nuclear Information System (INIS)

    Popli, P.K.

    2002-01-01

    Ever since discovery of x-rays, radiographers has been the prime user of radiation. With the passage of time, the harmful effects of radiation were detected. Some of radiographers, radiologists and public were affected by radiation, but today with enough knowledge of radiation, the prime responsibility of radiation protection lies with the radiographers only. The radiologist and physicist are also associated with radiation protection to some extent

  14. Measure by image analysis of industrial radiographs

    International Nuclear Information System (INIS)

    Brillault, B.

    1988-01-01

    A digital radiographic picture processing system for non destructive testing intends to provide the expert with computer tool, to precisely quantify radiographic images. The author describes the main problems, from the image formation to its characterization. She also insists on the necessity to define a precise process in order to automatize the system. Some examples illustrate the efficiency of digital processing for radiographic images [fr

  15. Early radiographic changes in radiation bone injury

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Early radiographic changes in radiation bone injury

    International Nuclear Information System (INIS)

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

    1986-01-01

    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

  17. Inferior alveolar canal course: a radiographic study.

    Science.gov (United States)

    Liu, Tie; Xia, Bing; Gu, Zhiyuan

    2009-11-01

    To describe the morphology and course of the inferior alveolar canal (IAC) as it appears in digital panoramic radiographs. Three hundred and eighty-six digital rotational panoramic radiographs (OPG) were studied using the Clinview Software (6.1.3.7 version, Instrumentarium). Among the 386 radiographs, 86 radiographs with 5-mm steel balls were used to calculate the magnification. The average magnification of radiographs in this study was 7.24+/-7.55%. The course of IAC as seen in the panoramic radiograph may be classified into four types: (1) linear curve, 12.75%, (2) spoon-shaped curve, 29.25%, (3) elliptic-arc curve, 48.5%, and (4) turning curve, 9.5%. On panoramic radiographs, the IAC appeared closest to the inferior border of the mandible in the region of the first molar. In relation to the teeth, on panoramic radiographs, the IAC appeared closest to the distal root tip of the third molar and furthest from the mesial root tip of the first molar. In the OPG, there are four types of IAC: linear, spoon shape, elliptic-arc, and turning curve. The data found in the study may be useful for dental implant, mandibule surgery, and dental anesthesia. The limitations of the panoramic radiograph in depicting the true three-dimensional (3D) morphology of the IAC are recognized, computed tomography (CT) and cone beam (CB)3D imaging being more precise.

  18. Reference Neutron Radiographs of Nuclear Reactor Fuel

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    Reference neutron radiographs of nuclear reactor fuel were produced by the Euraton Neutron Radiography Working Group and published in 1984 by the Reidel Publishing Company. In this collection a classification is given of the various neutron radiographic findings, that can occur in different parts...... of pelletized, annular and vibro-conpacted nuclear fuel pins. Those parts of the pins are shown where changes of appearance differ from those for the parts as fabricated. Also radiographs of those as fabricated parts are included. The collection contains 158 neutron radiographs, reproduced on photographic paper...... (twice enlarged) and on duplicating film (original size)....

  19. The hydrodynamic description of pseudorapidity distributions at ...

    Indian Academy of Sciences (India)

    2017-03-15

    Mar 15, 2017 ... hard to solve them analytically. From this point of view, hydrodynamics is tremendously complicated. This is the reason why from the time of ... erful calculation system, sophisticated skills are also needed for avoiding instabilities in solving partial dif- ferential hydrodynamic equations. Furthermore, as the.

  20. Two-fluid hydrodynamic model for semiconductors

    DEFF Research Database (Denmark)

    Maack, Johan Rosenkrantz; Mortensen, N. Asger; Wubs, Martijn

    2018-01-01

    The hydrodynamic Drude model (HDM) has been successful in describing the optical properties of metallic nanostructures, but for semiconductors where several different kinds of charge carriers are present an extended theory is required. We present a two-fluid hydrodynamic model for semiconductors...

  1. Towing Tank Measurements of Hydrodynamic Performance of a Horizontal Axis Tidal Turbine Under Unsteady Flow Conditions

    Science.gov (United States)

    2013-05-10

    hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and...completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of...torque using the same principles an airplane uses to remain in the air. The blades act as hydrofoils , creating lift and using the lift to turn the shaft

  2. Effect of Surface Roughness on Hydrodynamic Bearings

    Science.gov (United States)

    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.

  3. Measurement technique of calcaneal varus from axial view radiograph

    Directory of Open Access Journals (Sweden)

    Thossart Harnroongroj

    2015-01-01

    Full Text Available Background: Medial displaced posterior calcaneal tubercle creates varus deformity of an intraarticular calcaneal fracture. The fracture involves posterior calcaneal facet and the calcaneal body so we developed a measurement technique representing the angle between posterior facet and long axis of calcaneus using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references to obtain calcaneal varus angle. Materials and Methods: 52 axial view calcaneal radiographs of 26 volunteers were studied. Angles between posterior facet and long axis of calcaneus were measured using the measurements 1 and 2. Angle of measurement 1, as gold standard, was obtained from long axis and posterior facet of calcaneus whereas measurement 2 was obtained from a line, perpendicular to apex curve of lateral cortex of the lateral malleolus and a line parallel to the longitudinal bone trabeculae of posterior calcaneal tubercle. No more than 3° of difference in the angle of both measurements was accepted. Reliability of the measurement 2 was statistically tested. Results: Angles of measurement 1 and 2 were 90.04° ± 4.00° and 90.58° ± 3.78°. Mean of different degrees of both measurements was 0.54° ± 2.31° with 95% of confidence interval: 0.10°-1.88°. The statistical analysis of measurement 1 and 2 showed more than 0.75 of ICC and 0.826 of Pearson correlation coefficient. Conclusion: Technique of measurement 2 using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references has strong reliability for representing the angle between long axis and posterior facet of calcaneus to achieve calcaneal varus angle.

  4. Measurement technique of calcaneal varus from axial view radiograph.

    Science.gov (United States)

    Harnroongroj, Thossart; Tangmanasakul, Akegapon; Choursamran, Nattapol; Sudjai, Narumol; Harnroongroj, Thos

    2015-01-01

    Medial displaced posterior calcaneal tubercle creates varus deformity of an intraarticular calcaneal fracture. The fracture involves posterior calcaneal facet and the calcaneal body so we developed a measurement technique representing the angle between posterior facet and long axis of calcaneus using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references to obtain calcaneal varus angle. 52 axial view calcaneal radiographs of 26 volunteers were studied. Angles between posterior facet and long axis of calcaneus were measured using the measurements 1 and 2. Angle of measurement 1, as gold standard, was obtained from long axis and posterior facet of calcaneus whereas measurement 2 was obtained from a line, perpendicular to apex curve of lateral cortex of the lateral malleolus and a line parallel to the longitudinal bone trabeculae of posterior calcaneal tubercle. No more than 3° of difference in the angle of both measurements was accepted. Reliability of the measurement 2 was statistically tested. Angles of measurement 1 and 2 were 90.04° ± 4.00° and 90.58° ± 3.78°. Mean of different degrees of both measurements was 0.54° ± 2.31° with 95% of confidence interval: 0.10°-1.88°. The statistical analysis of measurement 1 and 2 showed more than 0.75 of ICC and 0.826 of Pearson correlation coefficient. Technique of measurement 2 using lateral malleolus and longitudinal bone trabeculae of posterior calcaneal tubercle as references has strong reliability for representing the angle between long axis and posterior facet of calcaneus to achieve calcaneal varus angle.

  5. Three axis attitude control system

    Science.gov (United States)

    Studer, Philip A. (Inventor)

    1988-01-01

    A three-axis attitude control system for an orbiting body comprised of a motor driven flywheel supported by a torque producing active magnetic bearing is described. Free rotation of the flywheel is provided about its central axis and together with limited angular torsional deflections of the flywheel about two orthogonal axes which are perpendicular to the central axis. The motor comprises an electronically commutated DC motor, while the magnetic bearing comprises a radially servoed permanent magnet biased magnetic bearing capable of producing cross-axis torques on the flywheel. Three body attitude sensors for pitch, yaw and roll generate respective command signals along three mutually orthogonal axes (x, y, z) which are coupled to circuit means for energizing a set of control coils for producing torques about two of the axes (x and y) and speed control of the flywheel about the third (z) axis. An energy recovery system, which is operative during motor deceleration, is also included which permits the use of a high-speed motor to perform effectively as a reactive wheel suspended in the magnetic bearing.

  6. Deterministic hydrodynamics: Taking blood apart

    Science.gov (United States)

    Davis, John A.; Inglis, David W.; Morton, Keith J.; Lawrence, David A.; Huang, Lotien R.; Chou, Stephen Y.; Sturm, James C.; Austin, Robert H.

    2006-10-01

    We show the fractionation of whole blood components and isolation of blood plasma with no dilution by using a continuous-flow deterministic array that separates blood components by their hydrodynamic size, independent of their mass. We use the technology we developed of deterministic arrays which separate white blood cells, red blood cells, and platelets from blood plasma at flow velocities of 1,000 μm/sec and volume rates up to 1 μl/min. We verified by flow cytometry that an array using focused injection removed 100% of the lymphocytes and monocytes from the main red blood cell and platelet stream. Using a second design, we demonstrated the separation of blood plasma from the blood cells (white, red, and platelets) with virtually no dilution of the plasma and no cellular contamination of the plasma. cells | plasma | separation | microfabrication

  7. Integration of quantum hydrodynamical equation

    Science.gov (United States)

    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.

  8. Anomalous hydrodynamics kicks neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Matthias, E-mail: mski@ua.edu [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 5C2 (Canada); Uhlemann, Christoph F. [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Bleicher, Marcus [Frankfurt Institute for Advanced Studies, Goethe-Universität Frankfurt (Germany); Institut für Theoretische Physik, Goethe Universität Frankfurt (Germany); Schaffner-Bielich, Jürgen [Institut für Theoretische Physik, Goethe Universität Frankfurt (Germany)

    2016-09-10

    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.

  9. Hydrodynamic interactions in concentrated solutions

    International Nuclear Information System (INIS)

    Walrand, Stephan

    1986-01-01

    This research thesis addresses the dynamics of concentrated solutions processed within the frame of the primitive model: charged spherical particles immersed in a viscous solvent. At high concentration, dynamics is determined by hydrodynamic interactions of n bodies. As a direct exploitation of these interactions is impossible, the author used an average field theory based on the use of effective mobility tensor, solution of the screened Navier-Stokes equation. The tensor is explicitly calculated by using the induced force formalism developed by Mazur and van Saarloos. The author also addressed the influence of chemical exchange on the diffusion coefficient. The Ackerson microscopic theory is generalized to include these exchanges. Thus, the mass action law is obtained through a kinetic way [fr

  10. Fluctuating nonlinear hydrodynamics of flocking

    Science.gov (United States)

    Yadav, Sunil Kumar; Das, Shankar P.

    2018-03-01

    Starting from a microscopic model, the continuum field theoretic description of the dynamics of a system of active ingredients or "particles" is presented. The equations of motion for the respective collective densities of mass and momentum follow exactly from that of a single element in the flock. The single-particle dynamics has noise and anomalous momentum dependence in its frictional terms. The equations for the collective densities are averaged over a local equilibrium distribution to obtain the corresponding coarse grained equations of fluctuating nonlinear hydrodynamics (FNH). The latter are the equations used frequently for describing active systems on the basis of intuitive arguments. The transport coefficients which appear in the macroscopic FNH equations are determined in terms of the parameters of the microscopic dynamics.

  11. Radiation hydrodynamics in solar flares

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Hydrodynamic dispersion within porous biofilms

    KAUST Repository

    Davit, Y.

    2013-01-23

    Many microorganisms live within surface-associated consortia, termed biofilms, that can form intricate porous structures interspersed with a network of fluid channels. In such systems, transport phenomena, including flow and advection, regulate various aspects of cell behavior by controlling nutrient supply, evacuation of waste products, and permeation of antimicrobial agents. This study presents multiscale analysis of solute transport in these porous biofilms. We start our analysis with a channel-scale description of mass transport and use the method of volume averaging to derive a set of homogenized equations at the biofilm-scale in the case where the width of the channels is significantly smaller than the thickness of the biofilm. We show that solute transport may be described via two coupled partial differential equations or telegrapher\\'s equations for the averaged concentrations. These models are particularly relevant for chemicals, such as some antimicrobial agents, that penetrate cell clusters very slowly. In most cases, especially for nutrients, solute penetration is faster, and transport can be described via an advection-dispersion equation. In this simpler case, the effective diffusion is characterized by a second-order tensor whose components depend on (1) the topology of the channels\\' network; (2) the solute\\'s diffusion coefficients in the fluid and the cell clusters; (3) hydrodynamic dispersion effects; and (4) an additional dispersion term intrinsic to the two-phase configuration. Although solute transport in biofilms is commonly thought to be diffusion dominated, this analysis shows that hydrodynamic dispersion effects may significantly contribute to transport. © 2013 American Physical Society.

  13. The hydrodynamics of dolphin drafting

    Directory of Open Access Journals (Sweden)

    Weihs Daniel

    2004-05-01

    Full Text Available Abstract 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.

  14. Vertical axis wind turbine airfoil

    Science.gov (United States)

    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.

  15. Radiographic techniques for digital mammography

    International Nuclear Information System (INIS)

    Horita, Katsuhei

    2007-01-01

    Since the differences in X-ray absorption between various breast tissues are small, a dedicated X-ray system for examination of the breast and a high-contrast, high-resolution screen/film system (SFM) (light-receiving system) are employed for X-ray diagnosis. Currently, however, there is a strong trend toward digital imaging in the field of general radiography, and this trend is also reflected in the field of mammographic examination. In fact, approximately 70% of facilities purchasing new mammography systems are now selecting a digital mammography system (DRM). Given this situation, this report reviews the differences between SFM and DRM and discusses the radiographic techniques and quality assurance procedures for digital mammography. (author)

  16. Picture chamber for radiographic system

    International Nuclear Information System (INIS)

    1977-01-01

    The picture chamber for a radiographic system is characterised by a base, a first electrode carried in the base, an X-ray irradiation window provided with an outer plate and an inner plate and a conducting surface which serves as a second electrode, which has a plate gripping it at each adjacent edge and which has at the sides a space which is occupied by a filling material, maintained at a steady pressure, by means of the mounting against the base and wherein the inner plate lies against the first electrode and which is provided with a split, and with means for the separation of the split in the area of the inner plate so that a fluid may be retained in the split. (G.C.)

  17. Radiographic study of the odontoma

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Hyung Kyu [Department of Oral Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1983-11-15

    The author studied clinically and radiologically 55 cases which had been diagnosed as odontoma in SNUDH. The obtained results were as follows: 1. In sex distribution, there was no prevalence in both sexes. And the incidence was the highest in the 2nd decade (16 patient, 29%). 2. There were 42 cases of compound odontoma (76%) and 13 cases of complex odontoma (24%). In most cases, compound odontoma was located at the anterior portion (34 cases, 81%) and complex odontoma at the posterior portions (9 cases, 69%). 3. There was no apparent clinical symptom in compound odontoma (83%), but in complex odontoma, 80% of cases show swelling. 4. The adjacent root resorption was not observed in any case. 5. Five cases radiographically diagnosed as cystic odontoma were not confirmed histopathologically.

  18. Radiographic study of the odontoma

    International Nuclear Information System (INIS)

    Ahn, Hyung Kyu

    1983-01-01

    The author studied clinically and radiologically 55 cases which had been diagnosed as odontoma in SNUDH. The obtained results were as follows: 1. In sex distribution, there was no prevalence in both sexes. And the incidence was the highest in the 2nd decade (16 patient, 29%). 2. There were 42 cases of compound odontoma (76%) and 13 cases of complex odontoma (24%). In most cases, compound odontoma was located at the anterior portion (34 cases, 81%) and complex odontoma at the posterior portions (9 cases, 69%). 3. There was no apparent clinical symptom in compound odontoma (83%), but in complex odontoma, 80% of cases show swelling. 4. The adjacent root resorption was not observed in any case. 5. Five cases radiographically diagnosed as cystic odontoma were not confirmed histopathologically.

  19. Visual perception and radiographic interpretation

    International Nuclear Information System (INIS)

    Papageorges, M.

    1998-01-01

    Although interpretation errors are common in radiology, their causes are still debated. Perceptual mechanisms appear to be responsible for a large proportion of mistakes made by both neophytes and trained radiologists. Erroneous perception of familiar contours can be triggered by unrelated opacities. Conversely, visual information cannot induce a specific perception if the observer is not familiar with the concept represented or its radiographicappearance. Additionally, the area of acute vision is smaller than is commonly recognized. Other factors, such as the attitude, beliefs,.: preconceptions, and expectations of the viewer, can affect what he or she ''sees'' whenviewing any object, including a radiograph. Familiarity with perceptual mechanisms and the limitations of the visual system as well as multiple readings may be necessary to reduce interpretation errors

  20. Radiographic evaluation of hallux valgus

    International Nuclear Information System (INIS)

    Richardson, M.L.; Hansen, S.T.; Kilcoyne, R.F.

    1987-01-01

    This paper presents the common preoperative and postoperative findings in hallux valgus, a common foot disorder of multiple etiologies, which can lead to significant foot pain and deformity. Little has been published in radiologic literature about the proper initial radiographic workup and the postoperative follow-up of this very common and very treatable cause of foot pain. Besides the primary findings of varus angulation of the first metatarsal and valgus angulation of the great toe, one may also see dorsal slaying of the first metatarsal head. As increased weight is borne by the central metatarsals, they may develop hyperostosis and stress fractures. Angular deformities of the hallux sesamoid joint and lesser toes may also be seen

  1. Gut Microbiota-brain Axis

    Science.gov (United States)

    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

  2. Conversion into numerical form of radiographic images

    International Nuclear Information System (INIS)

    Cappabianca, C.; Della Rocca, A.B.; Ferriani, S.

    1986-01-01

    Radiographic means are widely used for non destructive testing. However, human and technological factors strongly influence reliability of the results and further use of these technique. Image Processing can help to overtake those difficulties if radiographic films are previously digitized. This paper shows methods and equipments used in this field. The system EDI (Enea Digital. Imagery) operating in Casaccia Energy Research Centre is described

  3. Radiographic arthrosis after elbow trauma: interobserver reliability.

    NARCIS (Netherlands)

    Lindenhovius, A.; Karanicolas, P.J.; Bhandari, M.; Ring, D.; Kampen, A. van; et al.,

    2012-01-01

    PURPOSE: This study measured observer variation in radiographic rating of elbow arthrosis. METHODS: Thirty-seven independent orthopedic surgeons graded the extent of elbow arthrosis in 20 consecutive sets of plain radiographs, according to the Broberg and Morrey rating system (grade 0, normal joint;

  4. Radiographic Arthrosis After Elbow Trauma: Interobserver Reliability

    NARCIS (Netherlands)

    Lindenhovius, Anneluuk; Karanicolas, Paul Jack; Bhandari, Mohit; Ring, David; Allan, Cristopher; Axelrod, Terry; Baratz, Mark; Beingessner, Daphne; Cassidy, Charles; Coles, Chad; Conflitti, Joe; Rocca, Gregory Della; van Dijk, C. Niek; Elmans, L. H. G. J.; Feibe, Roger; Frihagen, Frede; Gosens, Taco; Greenberg, Jeffrey; Grosso, Elena; Harness, Neil; van der Heide, Huub; Jeray, Kyle; Kalainov, David; van Kampen, Albert; Kawamura, Sumito; Kloen, Peter; McCormac, Bob; McKee, Michael; Page, Richard; Pesantez, Rodrigo; Peters, Anil; Petrisor, Brad; Poolman, Rudolf; Richardson, Martin; Seiler, John; Swiontkowski, Marc; Trumble, Thomas; Wright, Thomas; Zalavras, Charalampos; Zura, Robert

    2012-01-01

    Purpose This study measured observer variation in radiographic rating of elbow arthrosis. Methods Thirty-seven independent orthopedic surgeons graded the extent of elbow arthrosis in 20 consecutive sets of plain radiographs, according to the Broberg and Morrey rating system (grade 0, normal joint;

  5. Chest Radiographic Findings in Newly Diagnosed Pulmonary ...

    African Journals Online (AJOL)

    Five hundred newly diagnosed cases of Pulmonary Tuberculosis were treated with directly observed short-course treatment and 100 of them had chest radiographic examination done. The various chest radiographic patterns in the 100 subjects were studied and included: Fluffy exudative changes 80(80%), fibrosis 70(70%) ...

  6. Equipment for fully automatic radiographic pipe inspection

    International Nuclear Information System (INIS)

    Basler, G.; Sperl, H.; Weinschenk, K.

    1977-01-01

    The patent describes a device for fully automatic radiographic testing of large pipes with longitudinal welds. Furthermore the invention enables automatic marking of films in radiographic inspection with regard to a ticketing of the test piece and of that part of it where testing took place. (RW) [de

  7. Dental Radiographs Ordered by Dental Professionals: an ...

    African Journals Online (AJOL)

    Conclusions: Even in resource limited settings dental caries is still the regular indication for taking dental radiographs, and periapical views are the most frequent type of radiograph ordered. Maxillary central incisors and mandibular molars were types of teeth commonly x-rayed mainly due to the aesthetic importance of the ...

  8. Consultant breast radiographers: Where are we now?

    International Nuclear Information System (INIS)

    Rees, Zebby

    2014-01-01

    Introduction: The aim of this study is to: • Evaluate the current role of the consultant breast radiographer. • Compare current practice with the four key components for consultant practice. • Gauge the support of radiologist colleagues. • Determine the other professional commitments involved with the role. This study could be the precursor for a macro study of all consultant radiographer practice in other specialities. Methodology: Methodology used was a comparative ethnographic study. Questionnaires to the 24 consultant breast radiographers currently in post, and consultant breast radiologists, who work with them, were conducted. Data collection was a qualitative thematic approach. Conclusion: Consultant breast radiographers provide high quality care to patients through excellent clinical practice, leadership and good communication. However, this study shows hospital Trusts emphasis for non medical consultants is for clinical practice first. Some radiologists are still a barrier to progression for consultant breast radiographers, and radiologists have a big influence in recruitment decisions. Consultant breast radiographer posts are well established, their numbers are increasing through recognition of the role and of their abilities and performance. Consultant breast radiographers state that becoming a consultant is the major achievement of their career, proving the Society of Radiographers' vision of the four-tier career structure has been well received by the radiography profession

  9. Radiographic examination of mesiodens and their associated complications.

    Science.gov (United States)

    Asaumi, J I; Shibata, Y; Yanagi, Y; Hisatomi, M; Matsuzaki, H; Konouchi, H; Kishi, K

    2004-03-01

    To examine mesiodens with regard to their status, their influence on adjacent teeth and their alteration during the follow-up period. From retrospective reviews of all patients who visited our institution from 1990-2001, we identified 200 patients (256 mesiodentes) who were shown to have mesiodentes on the basis of a periapical radiograph, a panoramic radiograph or an axial radiograph. The number of supernumerary teeth was one in 146 cases (73%), two in 52 cases (26%) and three in 2 cases (1%). Of 256 mesiodentes, the direction of the crown of the mesiodens was inverted in 172 (67%), in a normal direction in 69 (27%) and in a horizontal direction with regard to the tooth axis in 15 (6%). Of the 147 mesiodentes for which axial radiography was performed, 131 (89%) were located at a palatal site against the dental arch, 16 (11%) overlapped the dental arch and none were at a labial site. Of our 200 cases, a delay of eruption of the permanent central incisor was seen in 12 (6%), malposition or rotation of the central incisor in 5 (2.5%) and dentigerous cyst formation arising from mesiodens in 22 (11%). Marked movement of the mesiodens was seen in 10 cases during the follow-up period of 5-7 years. Some complication arising from mesiodens was seen in 19.5% of all cases in our research. Although mesiodentes are not caused by malocclusion, they may cause it. A long period of impaction of mesiodentes may bring about dentigerous cyst formation or movement of the mesiodentes.

  10. NOTE: Surface dose extrapolation measurements with radiographic film

    Science.gov (United States)

    Butson, Martin J.; Cheung, Tsang; Yu, Peter K. N.; Currie, Michael

    2004-07-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size.

  11. Vertical pelvic ring displacement in pelvic ring injury: Measurements in pelvic outlet radiograph and in cadavers.

    Science.gov (United States)

    Boontanapibul, Krit; Harnroongroj, Thos; Sudjai, Narumol; Harnroongroj, Thossart

    2015-01-01

    Vertical pelvic ring displacement (VPRD) is a serious injury and needs assessment. Pelvic outlet radiographs are routinely taken. However, relationship of radiographic and actual VPRD is still in question. Thus, measurement of VPRD from pelvic radiographs was studied. 2 dry pelvic bones and 1 sacrum from same cadaver was reconstructed to be the pelvic ring. Five specimens were enrolled. 10, 20 and 30 mm vertical displacement of right pelvic bone was performed at levels of sacroiliac joint and pubic symphysis for representing right VPRD. Then, the pelvis was set sacral inclination at 60° from X-ray table for outlet and anteroposterior pelvic radiographs. Right VPRD was measured by referring to superior most pelvic articular surface of both sacroiliac joints and sacral long axis. Radiographic VPRD and actual displacement were analyzed by Pearson correlation coefficient at more than 0.90 for the strong correlation and strongly significant simple regression analysis was set at P outlet and anteroposterior pelvic views at 10 mm actual displacement were 20.12 ± 1.98 and 4.08 ± 3.76 mm, at 20 mm were 40.31 ± 1.97 and 9.94 ± 7.27 mm and at 30 mm were 58.56 ± 2.53 and 11.29 ± 2.89 mm. Statistical analyses showed that radiographic VPRD from pelvic outlet view is 1.95 times of actual displacement with strong correlation at 0.992 coefficient and strongly significant regression analysis (P outlet radiograph provides efficient measurement of VPRD with 2 times of actual displacement.

  12. Radiographic assessment of endodontic working length

    Directory of Open Access Journals (Sweden)

    Osama S Alothmani

    2013-01-01

    Full Text Available The use of radiographs for working length determination is usual practice in endodontics. Exposing radiographs following the principles of the paralleling technique allows more accurate length determination compared to the bisecting-angle method. However, it has been reported that up to 28.5% of cases can have the file tip extending beyond the confines of the root canals despite an acceptable radiographic appearance. The accuracy of radiographic working length determination could be affected by the location of the apical foramen, tooth type, canal curvature and superimposition of surrounding structures. Variations among observers by virtue of training and experience may also influence the accuracy of the procedure. The interpretation of radiographs could be affected by film speed and viewing conditions, with the superiority of digital imaging over conventional radiography for working length determination remaining debatable. The combination of several methods is recommended for acquiring the most accurate working length.

  13. Consultant radiographers: Profile of the first generation

    International Nuclear Information System (INIS)

    Forsyth, Lesley J.; Maehle, Valerie

    2010-01-01

    Aim: The aim of this research is to examine the profile of first generation consultant radiographers: their demographics, educational backgrounds, qualifications and training, career experience and progression, teaching, lecturing and research activities. Method: Participant recruitment was drawn from the Society and College of Radiographers consultant radiographer group. Data collection involved a self-administered paper based and web based questionnaire. Results: Participant response rate of 55% (n = 11). Conclusions: The profile of the first consultant radiographer cohort reflects a diverse and eclectic mix. While some aspects of their development such as educational background, clinical training and skills enhancement are comparable to nurse consultants, clinical experience and employment history show some differences. Commitment to development of expert clinical skills is evident within the profile of the first generation cohort of consultant radiographers however research and leadership training are not strong features.

  14. Validity of radiographic assessment of ankylosis

    International Nuclear Information System (INIS)

    Stenvik, A.; Beyer-Olsen, E.; Aabyholm, F.; Haanaes, H.R.; Gerner, N.W.

    1990-01-01

    The accuracy and sensitivity of radiographic assessments of reactive processes in dental tissues were evaluated by comparison of radiographs and histologic sections. Experimental lesions inflicted on the roots of 10 monkey incisors had been observed by means of serially obtained radiographs over a period of 315 to 370 days. The material was used for evaluation of radiographic assessment of ankylosis. For comparative purposes, assessment of the experimental lesion penetrating to the pulp and periapical radiolucency was added. True and falsely positive or negative recordings formed the basis for calculation of the accuracy and sensitivity of the radiographic assessment. The sensitivity, or the obsevers ability to detect the actual changes, was high for pulp penetration, intermediate for inflammation, and low for ankylosis. 6 refs., 3 figs., 2 tabs

  15. Chest radiographic findings in acute paraquat poisoning

    International Nuclear Information System (INIS)

    Na, Gyeong Gyun; Lee, Mi Sook; Kim, Hee Jun; Sun, In O

    2016-01-01

    To describe the chest radiographic findings of acute paraquat poisoning. 691 patients visited the emergency department of our hospital between January 2006 and October 2012 for paraquat poisoning. Of these 691, we identified 56 patients whose initial chest radiographs were normal but who developed radiographic abnormalities within one week. We evaluated their radiographic findings and the differences in imaging features based on mortality. The most common finding was diffuse consolidation (29/56, 52%), followed by consolidation with linear and nodular opacities (18/56, 32%), and combined consolidation and pneumomediastinum (7/56, 13%). Pleural effusion was noted in 17 patients (30%). The two survivors (4%) showed peripheral consolidations, while the 54 patients (96%) who died demonstrated bilateral (42/54, 78%) or unilateral (12/54, 22%) diffuse consolidations. Rapidly progressing diffuse pulmonary consolidation was observed within one week on follow-up radiographs after paraquat ingestion in the deceased, but the survivors demonstrated peripheral consolidation

  16. Chest radiographic findings in acute paraquat poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Na, Gyeong Gyun; Lee, Mi Sook; Kim, Hee Jun; Sun, In O [Presbyterian Medical Center, Jeonju (Korea, Republic of)

    2016-01-15

    To describe the chest radiographic findings of acute paraquat poisoning. 691 patients visited the emergency department of our hospital between January 2006 and October 2012 for paraquat poisoning. Of these 691, we identified 56 patients whose initial chest radiographs were normal but who developed radiographic abnormalities within one week. We evaluated their radiographic findings and the differences in imaging features based on mortality. The most common finding was diffuse consolidation (29/56, 52%), followed by consolidation with linear and nodular opacities (18/56, 32%), and combined consolidation and pneumomediastinum (7/56, 13%). Pleural effusion was noted in 17 patients (30%). The two survivors (4%) showed peripheral consolidations, while the 54 patients (96%) who died demonstrated bilateral (42/54, 78%) or unilateral (12/54, 22%) diffuse consolidations. Rapidly progressing diffuse pulmonary consolidation was observed within one week on follow-up radiographs after paraquat ingestion in the deceased, but the survivors demonstrated peripheral consolidation.

  17. Explicit 3D continuum fracture modeling with smooth particle hydrodynamics

    Science.gov (United States)

    Benz, W.; Asphaug, E.

    1993-01-01

    Impact phenomena shaped our solar system. As usual for most solar system processes, the scales are far different than we can address directly in the laboratory. Impact velocities are often much higher than we can achieve, sizes are often vastly larger, and most impacts take place in an environment where the only gravitational force is the mutual pull of the impactors. The Smooth Particle Hydrodynamics (SPH) technique has been applied in the past to the simulations of giant impacts. In these simulations, the colliding objects were so massive (at least a sizeable fraction of the Earth's mass) that material strength was negligible compared to gravity. This assumption can no longer be made when the bodies are much smaller. To this end, we have developed a 3D SPH code that includes a strength model to which we have added a von Mises yielding relation for stresses beyond the Hugoniot Elastic Limit. At the lower stresses associated with brittle failure, we use a rate-dependent strength based on the nucleation of incipient flaws whose number density is given by a Weibull distribution. Following Grady and Kipp and Melosh et al., we introduce a state variable D ('damage'), 0 less than D less than 1, which expresses the local reduction in strength due to crack growth under tensile loading. Unfortunately for the hydrodynamics, Grady and Kipp's model predicts which fragments are the most probable ones and not the ones that are really formed. This means, for example, that if a given laboratory experiment is modeled, the fragment distribution obtained from the Grady-Kipp theory would be equivalent to a ensemble average over many realizations of the experiment. On the other hand, the hydrodynamics itself is explicit and evolves not an ensemble average but very specific fragments. Hence, there is a clear incompatibility with the deterministic nature of the hydrodynamics equations and the statistical approach of the Grady-Kipp dynamical fracture model. We remedy these shortcomings

  18. Relativistic conformal magneto-hydrodynamics from holography

    International Nuclear Information System (INIS)

    Buchbinder, Evgeny I.; Buchel, Alex

    2009-01-01

    We use the AdS/CFT correspondence to study first-order relativistic viscous magneto-hydrodynamics of (2+1)-dimensional conformal magnetic fluids. It is shown that the first order magneto-hydrodynamics constructed following Landau and Lifshitz from the positivity of the entropy production is inconsistent. We propose additional contributions to the entropy motivated dissipative current and, correspondingly, new dissipative transport coefficients. We use the strongly coupled M2-brane plasma in external magnetic field to show that the new magneto-hydrodynamics leads to self-consistent results in the shear and sound wave channels.

  19. Dileptons from transport and hydrodynamical models

    International Nuclear Information System (INIS)

    Huovinen, P.; Koch, V.

    2000-01-01

    Transport and hydrodynamical models used to describe the expansion stage of a heavy-ion collision at the CERN SPS give different dilepton spectrum even if they are tuned to reproduce the observed hadron spectra. To understand the origin of this difference we compare the dilepton emission from transport and hydrodynamical models using similar initial states in both models. We find that the requirement of pion number conservation in a hydrodynamical model does not change the dilepton emission. Also the mass distribution from the transport model indicates faster cooling and longer lifetime of the fireball

  20. Tuning bacterial hydrodynamics with magnetic fields

    Science.gov (United States)

    Pierce, C. J.; Mumper, E.; Brown, E. E.; Brangham, J. T.; Lower, B. H.; Lower, S. K.; Yang, F. Y.; Sooryakumar, R.

    2017-06-01

    Magnetotactic bacteria are a group of motile prokaryotes that synthesize chains of lipid-bound, magnetic nanoparticles called magnetosomes. This study exploits their innate magnetism to investigate previously unexplored facets of bacterial hydrodynamics at surfaces. Through use of weak, uniform, external magnetic fields and local, micromagnetic surface patterns, the relative strength of hydrodynamic, magnetic, and flagellar force components is tuned through magnetic control of the bacteria's orientation. The resulting swimming behaviors provide a means to experimentally determine hydrodynamic parameters and offer a high degree of control over large numbers of living microscopic entities. The implications of this controlled motion for studies of bacterial motility near surfaces and for micro- and nanotechnology are discussed.

  1. Digital subtraction radiographic evaluation of the standardize periapical intraoral radiographs

    International Nuclear Information System (INIS)

    Cho, Bong Hae; Nah, Kyung Soo

    1993-01-01

    The geometrically standardized intraoral radiographs using 5 occlusal registration material were taken serially from immediate, 1 day, 2, 4, 8, 12 and 16 weeks after making the bite blocks. The qualities of those subtracted images were evaluated to check the degree of reproducibility of each impression material. The results were as follows: 1. The standard deviations of the grey scales of the overall subtracted images were 4.9 for Exaflex, 7.2 for Pattern resin, 9.0 for Tooth Shade Acrylic, 12.2 for XCP only, 14.8 for Impregum. 2. The standard deviation of the grey scales of the overall subtracted images were grossly related to those of the localized horizontal line of interest. 3. Exaflex which showed the best subtracted image quality had 15 cases of straight, 14 cases of wave, 1 case of canyon shape. Impregum which showed the worst subtracted image quality had 4 cases of straight, 8 cases of wave, 18 cases of canyon shape respectively.

  2. The hydrodynamics of swimming microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Lauga, Eric [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093-0411 (United States); Powers, Thomas R [Division of Engineering, Brown University, Providence, RI 02912-9104 (United States)], E-mail: elauga@ucsd.edu, E-mail: Thomas_Powers@brown.edu

    2009-09-15

    Cell motility in viscous fluids is ubiquitous and affects many biological processes, including reproduction, infection and the marine life ecosystem. Here we review the biophysical and mechanical principles of locomotion at the small scales relevant to cell swimming, tens of micrometers and below. At this scale, inertia is unimportant and the Reynolds number is small. Our emphasis is on the simple physical picture and fundamental flow physics phenomena in this regime. We first give a brief overview of the mechanisms for swimming motility, and of the basic properties of flows at low Reynolds number, paying special attention to aspects most relevant for swimming such as resistance matrices for solid bodies, flow singularities and kinematic requirements for net translation. Then we review classical theoretical work on cell motility, in particular early calculations of swimming kinematics with prescribed stroke and the application of resistive force theory and slender-body theory to flagellar locomotion. After examining the physical means by which flagella are actuated, we outline areas of active research, including hydrodynamic interactions, biological locomotion in complex fluids, the design of small-scale artificial swimmers and the optimization of locomotion strategies.

  3. The hydrodynamics of swimming microorganisms

    International Nuclear Information System (INIS)

    Lauga, Eric; Powers, Thomas R

    2009-01-01

    Cell motility in viscous fluids is ubiquitous and affects many biological processes, including reproduction, infection and the marine life ecosystem. Here we review the biophysical and mechanical principles of locomotion at the small scales relevant to cell swimming, tens of micrometers and below. At this scale, inertia is unimportant and the Reynolds number is small. Our emphasis is on the simple physical picture and fundamental flow physics phenomena in this regime. We first give a brief overview of the mechanisms for swimming motility, and of the basic properties of flows at low Reynolds number, paying special attention to aspects most relevant for swimming such as resistance matrices for solid bodies, flow singularities and kinematic requirements for net translation. Then we review classical theoretical work on cell motility, in particular early calculations of swimming kinematics with prescribed stroke and the application of resistive force theory and slender-body theory to flagellar locomotion. After examining the physical means by which flagella are actuated, we outline areas of active research, including hydrodynamic interactions, biological locomotion in complex fluids, the design of small-scale artificial swimmers and the optimization of locomotion strategies.

  4. Fluctuating hydrodynamics for ionic liquids

    Science.gov (United States)

    Lazaridis, Konstantinos; Wickham, Logan; Voulgarakis, Nikolaos

    2017-04-01

    We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau-Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids.

  5. Hydrodynamically driven colloidal assembly in dip coating.

    Science.gov (United States)

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

    2013-05-03

    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] particles in suspension. The hydrodynamically driven assembly documented here is consistent with stripe pattern formations observed experimentally in dip coating.

  6. Hydrodynamic limit of interacting particle systems

    International Nuclear Information System (INIS)

    Landim, C.

    2004-01-01

    We present in these notes two methods to derive the hydrodynamic equation of conservative interacting particle systems. The intention is to present the main ideas in the simplest possible context and refer for details and references. (author)

  7. Hydrodynamic approach to electronic transport in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Narozhny, Boris N. [Institute for Theoretical Condensed Matter Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Gornyi, Igor V. [Institute for Theoretical Condensed Matter Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe (Germany); Ioffe Physical Technical Institute, St. Petersburg (Russian Federation); Mirlin, Alexander D. [Institute for Theoretical Condensed Matter Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe (Germany); Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation); Schmalian, Joerg [Institute for Theoretical Condensed Matter Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Institute for Solid State Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2017-11-15

    The last few years have seen an explosion of interest in hydrodynamic effects in interacting electron systems in ultra-pure materials. In this paper we briefly review the recent advances, both theoretical and experimental, in the hydrodynamic approach to electronic transport in graphene, focusing on viscous phenomena, Coulomb drag, non-local transport measurements, and possibilities for observing nonlinear effects. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Relabeling symmetries in hydrodynamics and magnetohydrodynamics

    International Nuclear Information System (INIS)

    Padhye, N.; Morrison, P.J.

    1996-04-01

    Lagrangian symmetries and concomitant generalized Bianchi identities associated with the relabeling of fluid elements are found for hydrodynamics and magnetohydrodynamics (MHD). In hydrodynamics relabeling results in Ertel's theorem of conservation of potential vorticity, while in MHD it yields the conservation of cross helicity. The symmetries of the reduction from Lagrangian (material) to Eulerian variables are used to construct the Casimir invariants of the Hamiltonian formalism

  9. OFF-AXIS THERMAL AND SYNCHROTRON EMISSION FOR SHORT GAMMA RAY BURST

    Science.gov (United States)

    Xie, Xiaoyi

    2018-01-01

    We present light curves of photospheric and synchrotron emission from a relativistic jet propagating through the ejecta cloud of a neutron star merger. We use a moving-mesh relativistic hydrodynamics code with adaptive mesh refinement to compute the continuous evolution of jet over 13 orders of magnitude in radius from the scale of the central merger engine all the way through the late afterglow phase. As the jet propagates through the cloud it forms a hot cocoon surrounding the jet core. We find that the photospheric emission released by the hot cocoon is bright for on-axis observers and is detectable for off-axis observers at a wide range of observing angles for sufficiently close sources. As the jet and cocoon drive an external shock into the surrounding medium we compute synchrotron light curves and find bright emission for off-axis observers which differs from top-hat Blandford-McKee jets, especially for lower explosion energies.

  10. Radiographic evaluation of AIDS patients

    Energy Technology Data Exchange (ETDEWEB)

    Le Blang, S.D.; Witheman, M.L.; Donovan Post, M.J.; Casillas, J.V. [Miami Univ., FL (United States). Dept. of Radiology

    1995-09-01

    Morphological imaging, based on the use of various techniques including ultrasound, X-ray computed tomography (CT), and magnetic resonance imaging (MRI), plays an important role in the characterization, diagnosis and follow-up of patients with Human Immunodeficiency Virus (HIV) infection and Acquired Immunodeficiency Syndrome (AIDS). While the presence of thoracic infections, the most frequently observed illnesses in AIDS patients, can best be performed by using conventional chest films and CT, the assessment of cerebral involvement in AIDS patients - characterized by the presence of focal masses, demyelination, meningitis, and infarction - is best achieved using MRI. The work-up of patients with gastrointestinal symptoms should include the use of ultrasound for the evaluation of visceral involvement and lymphadenopathy, completed by CT to further characterize pathologic conditions in either the bowel or visceral organs. Ultrasound is the screening exam of choice in AIDS patients with suspected renal disease, but other methods may be necessary for the assessment of the complications due to pharmacological treatment. Musculoskeletal complications may require the combined use of all the above methods, since they may be caused by infections, tumors and rheumatologic illness. The use of the radiographic methods for the detection of the numerous forms of infections and malignancies in AIDS patients is described in detail for the various body districts.

  11. Consultant radiographer leadership - A discussion

    International Nuclear Information System (INIS)

    Hogg, Peter; Hogg, Dianne; Henwood, Suzanne

    2008-01-01

    Effective leadership can be defined in many ways and is an essential element of successful organisations; poor leadership can result in problems such as low staff morale, high staff turnover and reduced productivity. Effective leadership behaviours are well documented in the literature and various leadership models have been proposed that illustrate these behaviours. This discussion paper does not focus on any particular model. Instead it considers the 'Leadership Qualities Framework' which was developed specifically for use within the UK National Health Service. This framework draws upon a range of leadership models and as such it gives a broad indication of leadership behaviours. The framework comprises three components - 'personal qualities', 'setting direction' and 'delivering the service'. This paper commences with an argument as to why effective leadership is important in organisations generally, and specifically within healthcare organisations. Various examples of leadership are illustrated from within and outside the NHS in order to demonstrate effective leadership behaviours. The Leadership Qualities Framework is then examined, along with scenarios to illustrate effective leadership behaviours in context (i.e. within a healthcare organisation). Subsequent reflections on the scenarios aim to identify leadership behaviours that are explained within the framework. The final element of this paper draws on [limited] published evidence of where consultant radiographers have demonstrated effective leadership behaviours. In this section the published evidence is examined and reflected upon. At the end of the article we indicate additional reading for those who wish to further develop their theoretical and practical leadership skills

  12. Radiographic evaluation of AIDS patients

    International Nuclear Information System (INIS)

    Le Blang, S.D.; Witheman, M.L.; Donovan Post, M.J.; Casillas, J.V.

    1995-01-01

    Morphological imaging, based on the use of various techniques including ultrasound, X-ray computed tomography (CT), and magnetic resonance imaging (MRI), plays an important role in the characterization, diagnosis and follow-up of patients with Human Immunodeficiency Virus (HIV) infection and Acquired Immunodeficiency Syndrome (AIDS). While the presence of thoracic infections, the most frequently observed illnesses in AIDS patients, can best be performed by using conventional chest films and CT, the assessment of cerebral involvement in AIDS patients - characterized by the presence of focal masses, demyelination, meningitis, and infarction - is best achieved using MRI. The work-up of patients with gastrointestinal symptoms should include the use of ultrasound for the evaluation of visceral involvement and lymphadenopathy, completed by CT to further characterize pathologic conditions in either the bowel or visceral organs. Ultrasound is the screening exam of choice in AIDS patients with suspected renal disease, but other methods may be necessary for the assessment of the complications due to pharmacological treatment. Musculoskeletal complications may require the combined use of all the above methods, since they may be caused by infections, tumors and rheumatologic illness. The use of the radiographic methods for the detection of the numerous forms of infections and malignancies in AIDS patients is described in detail for the various body districts

  13. Hydrodynamic modelling for relativistic heavy-ion collisions at RHIC ...

    Indian Academy of Sciences (India)

    progress on hydrodynamic modelling, investigation on the flow data and the extraction of the QGP shear viscosity in relativistic heavy-ion collisions at RHIC and LHC. 2. Hydrodynamic modelling – a short introduction. 2.1 Viscous hydrodynamics. Relativistic hydrodynamics is a macroscopic tool to simulate the QGP fireball ...

  14. Dynamic analysis of liquid storage tank including hydrodynamic interaction by boundary element method

    International Nuclear Information System (INIS)

    Hwang, I.T.; Ting, K.

    1987-01-01

    Dynamic response of liquid storage tanks considering the hydrodynamic interactions due to earthquake ground motion has been extensively studied. Several finite element procedures, such as Balendra et. al. (1982) and Haroun (1983), have been devoted to investigate the dynamic interaction between the deformable wall of the tank and the liquid. Further, if the geometry of the storage tank can not be described by axi-symmetric case, the tank wall and the fluid domain must be discretized by three dimensional finite elements to investigate the fluid-structure-interactions. Thus, the need of large computer memory and expense of vast computer time usually make this analysis impractical. To demonstrate the accuracy and reliability of the solution technique developed herein, the dynamic behavior of ground-supported, deformed, cylindrical tank with incompressible fluid conducted by Haroun (1983) are analyzed. Good correlations of hydrodynamic pressure distribution between the computed results with the referenced solutions are noted. The fluid compressibility significantly affects the hydrodynamic pressures of the liquid-tank-interactions and the work which is done on this discussion is still little attention. Thus, the influences of the compressibility of the liquid on the reponse of the liquid storage due to ground motion are then drawn. By the way, the complex-valued frequency response functions for hydrodynamic forces of Haroun's problem are also displayed. (orig./GL)

  15. Radiographers and trainee radiologists reporting accident radiographs: A comparative plain film-reading performance study

    International Nuclear Information System (INIS)

    Buskov, L.; Abild, A.; Christensen, A.; Holm, O.; Hansen, C.; Christensen, H.

    2013-01-01

    Aim: To compare the diagnostic accuracy and clinical validity of reporting radiographers with that of trainee radiologists whom they have recently joined in reporting emergency room radiographs at Bispebjerg University Hospital. Materials and methods: Plain radiographs of the appendicular skeleton from 1000 consecutive emergency room patients were included in the study: 500 primarily reported by radiographers and 500 by trainee radiologists. The final reporting was subsequently undertaken by a consultant radiologist in consensus with an orthopaedic surgeon. Two observers classified reports as either true positive/negative or false positive/negative based on the final report, which was considered the reference standard. To evaluate the severity of incorrect primary reports, errors were graded into three categories concerning clinical impact and erroneous reports graded as the most severe category were subsequently analysed. Mann–Whitney and Chi-squared tests were used to compare differences and associations between radiographers versus trainee radiologists regarding film reporting. Results: The sensitivity for correct diagnosis was 99% for reporting radiographers and 94% for trainee radiologists. The specificity was found to be 97% for reporting radiographers and 99% for trainee radiologists. Radiographers missed significantly fewer fractures (n = 2) than trainee radiologists (n = 14; p = 0.006) but had a higher, but not significant, degree of overcalling. No significant difference was found between groups regarding clinical impact of incorrect reporting. Conclusion: Trained radiographers report accident radiographs of the extremities with high accuracy and constitute a qualified resource to help meet increasing workload and demands in quality standards.

  16. Shock-hydrodynamics experiments on the Nova laser

    International Nuclear Information System (INIS)

    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 ∼ 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

  17. Radiographers and radiologists reporting plain radiograph requests from accident and emergency and general practice

    International Nuclear Information System (INIS)

    Brealey, S.D.; King, D.G.; Hahn, S.; Crowe, M.; Williams, P.; Rutter, P.; Crane, S.

    2005-01-01

    AIM: To assess selectively trained radiographers and consultant radiologists reporting plain radiographs for the Accident and Emergency Department (A and E) and general practitioners (GPs) within a typical hospital setting. METHODS: Two radiographers, a group of eight consultant radiologists, and a reference standard radiologist independently reported under controlled conditions a retrospectively selected, random, stratified sample of 400 A and E and 400 GP plain radiographs. An independent consultant radiologist judged whether the radiographer and radiologist reports agreed with the reference standard report. Clinicians then assessed whether radiographer and radiologist incorrect reports affected confidence in their diagnosis and treatment plans, and patient outcome. RESULTS: For A and E and GP plain radiographs, respectively, there was a 1% (95% confidence interval (CI) -2 to 5) and 4% (95% CI -1 to 8) difference in reporting accuracy between the two professional groups. For both A and E and GP cases there was an 8% difference in the clinicians' confidence in their diagnosis based on radiographer or radiologist incorrect reports. For A and E and GP cases, respectively, there was a 2% and 8% difference in the clinicians' confidence in their management plans based on radiographer or radiologist incorrect reports. For A and E and GP cases, respectively, there was a 1% and 11% difference in effect on patient outcome of radiographer or radiologist incorrect reports. CONCLUSION: There is the potential to extend the reporting role of selectively trained radiographers to include plain radiographs for all A and E and GP patients. Further research conducted during clinical practice at a number of sites is recommended

  18. Reflections on the role of consultant radiographers in the UK: what is a consultant radiographer?

    OpenAIRE

    Booth, Lisa; Henwood, Suzanne; Miller, Paul K.

    2016-01-01

    Context: This paper is the second paper from a two year in depth case study, exploring the role of consultant radiographers in the UK.\\ud \\ud Methods: A longitudinal case study approach was used to determine the role of consultant radiographers. Interviews were used to explore experiences of being a consultant, which were analysed using thematic analysis. Eight consultant radiographers participated (Note, two of the consultants withdrew after the first interview due to workload). Therefore tw...

  19. Radiation recommendation series: administratively required dental radiographs

    International Nuclear Information System (INIS)

    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

  20. Modified Newman and Friedman Extraoral Radiographic Technique

    OpenAIRE

    Saberi, Eshagali; Hafezi, Ladan; Farhadmolashahi, Narges; Mokhtari, Manoochehr

    2012-01-01

    Introduction Good radiographs are required for endodontic therapy and because some patient’s are intolerant to intraoral films and/or sensors, this can cause complications in endodontic treatment. Extraoral film placement can be used to obtain clinically diagnostic and working radiographs. Materials and Methods The no. 2 receptor was placed against the model’s cheek and centered in the molar-premolar area. The central beam was directed toward this area from the opposite side. The vertical and...

  1. A radiographic study of pediatric ulnar anatomy.

    Science.gov (United States)

    Cravino, Mattia; Oni, Julius K; Sala, Debra A; Chu, Alice

    2014-01-01

    The adult ulna has a unique bony architecture that has been described in the literature, but, to the best of our knowledge, the ulnar anatomy in children has not been described. We examined 75 anteroposterior (AP) and 64 lateral radiographs (29 were bilateral) of 50, 0.5- to 11-year-old, healthy children's forearms. On AP radiographs, the total ulnar length, the ulnar proximal angle, the ulnar distal angle, and the distance between each angle from the tip of the triceps insertion; and, on lateral radiographs, the ulnar length and bow deviation were measured. The correlation between age and radiographic measurements, differences based on sex, differences compared with adults' measurements, and interobserver/intraobserver reliability were assessed. Age had a very strong/strong positive correlation with length/distance measurements on both AP and lateral radiographs. Only AP ulnar distal angle was significantly different between sexes (females > males). Compared with the adult ulnar studies, the AP proximal angle in children is significantly smaller and the location of this angle is significantly more distal. Interobserver and intraobserver reliability were very good for length/distance measurements on AP and lateral radiographs. The knowledge of pediatric ulnar anatomy could be helpful in the treatment of forearm deformities due to multiple hereditary exostosis and osteogenesis imperfecta, and in the treatment of ulnar fractures, particularly in Monteggia variants, where restoration of the correct forearm anatomy is essential to obtain good clinical and functional results. Study of diagnostic test, Level II.

  2. Early characteristic radiographic changes in mucolipidosis II

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Lillian M. [Lucile Packard Children' s Hospital and Stanford University, Pediatric Radiology, Palo Alto, CA (United States); Lachman, Ralph S. [Lucile Packard Children' s Hospital and Stanford University, Pediatric Radiology, Palo Alto, CA (United States); University of California, International Skeletal Dysplasia Registry, Los Angeles, CA (United States)

    2016-11-15

    Although mucolipidosis type II has similar metabolic abnormalities to those found in all the mucopolysaccharidoses and mucolipidoses, there are distinctive diagnostic radiographic changes of mucolipidosis II in the perinatal/newborn/infant period. To describe the early characteristic radiographic changes of mucolipidosis II and to document when these changes manifest and resolve. We retrospectively reviewed radiographs and clinical records of 19 cases of mucolipidosis II from the International Skeletal Dysplasia Registry (1971-present; fetal age to 21/2 years). A radiologist with special expertise in skeletal dysplasias evaluated the radiographs. The most common abnormalities were increased vertebral body height (80%, nonspecific), talocalcaneal stippling (86%), periosteal cloaking (74%) and vertebral body rounding (50%). Unreported findings included sacrococcygeal sclerosis (54%) and vertebral body sclerosis (13%). Rickets and hyperparathyroidism-like (pseudohyperparathyroidism) changes (rarely reported) were found in 33% of cases. These changes invariably started in the newborn period and resolved by 1 year of age. The conversion from these early infantile radiographic features to dysostosis multiplex changes occurred in 41% of cases, and within the first year after birth. Several findings strongly suggest the diagnosis of mucolipidosis II, including cloaking in combination with one or more of the following radiographic criteria: talocalcaneal stippling, sacrococcygeal or generalized vertebral body sclerosis, vertebral body rounding, or rickets/hyperparathyroidism-like changes in the perinatal/newborn/infancy period. These findings are not found in the other two forms of mucolipidosis nor in any of the mucopolysaccharidoses. (orig.)

  3. Radiographic manifestations of arthritis in AIDS patients

    International Nuclear Information System (INIS)

    Rosenberg, Z.S.; Norman, A.; Solomon, G.

    1988-01-01

    The purpose of this study is to familiarize the radiologist with a newly discovered association between arthritis and acquired immunodeficiency syndrome (AIDS). The authors retrospectively reviewed the clinical and radiographic findings in 31 patients with human immunodeficiency virus (HIV) infection referred to their rheumatology clinic with musculoskeletal complaints. The patients carried a wide range of clinical diagnosis including Reiter syndrome, psoriatic arthritis, undifferentiated seronegative arthritis, isolated enthesopathies, rheumatoid arthritis and osteonecrosis. Radiographs were available in 24 of the 31 patients, and in 20 they showed radiographic features of arthritis, which included soft-tissue swelling periarticular osteoporosis, synovial effusions, sacroiliitis, periosteal reaction, joint space narrowing, marginal erosions, and osteonecrosis. Although the radiographic abnormalities were frequently mild, they were significant, given the short duration of disease in many of their patients (weeks to months) at the time radiographs were obtained. The range of radiographic findings in their series was varied and paralleled the wide range of clinical diagnoses. No findings were pathognomonic for HIV-associated arthritis. Nevertheless, HIV infection needs to be considered in any patient belonging to a recognized risk group who presents with musculoskeletal disease. This is particularly important since immunosupressive drugs used for the treatment of arthritis can be detrimental to patients with HIV infection

  4. Radiographic signs and diagnosis of dental disease

    International Nuclear Information System (INIS)

    Bellows, J.

    1993-01-01

    Dental radiographs are critical for the complete assessment and treatment of dental diseases. Dental radiography is commonly used to evaluate congenital dental defects, periodontal disease, orthodontic manipulations, oral tumors, endodontic treatments, oral trauma, and any situation where an abnormality is suspected. Although standard radiographic equipment and film can be used to produce dental radiographs, dental X-ray equipment and film provide superior quality images and greater convenience of animal patient positioning. An understanding of normal dental radiographic anatomy is important when interpreting dental radiographs. Stage III periodontitis is the earliest stage of periodontal disease at which radiographic abnormalities become apparent. Bone loss associated with periodontal disease can be classified as either horizontal or vertical. Periapical radiolucencies can represent granulomas, cysts, or abscesses, whereas periapical radiodensities may represent sclerotic bone or condensing osteitis. Lytic lesions of the bone of the jaw often represent oral neoplasms. Neoplasms also can displace or disrupt teeth in the dental arch. Resorptive lesions can be external or internal and appear as radiolucent areas involving the external surface of the root or the pulp cavity, respectively. Feline dental resorptive lesions, also known as odontoclastic resorptions, are a specific form of dental resorptive lesions unique to cats

  5. Pulsed high-energy radiographic machine emitting x-rays: PHERMEX

    International Nuclear Information System (INIS)

    Dick, R.D.

    1976-01-01

    The PHERMEX facility that is used to provide radiography of explosives and explosive-driven systems is described. This facility allows precision flash radiography of large objects containing high atomic number materials. The facility consists of a high-current, three-cavity, 27-MeV linear electron accelerator; a 13.5-MW radiofrequency power source; a timing, firing, and signal detection system; and a data acquisition system. PHERMEX was built in the early part of the 1960s to complement other hydrodynamics facilities at Los Alamos and to implement studies related to shock waves, detonation, and other hydrodynamic phenomena. After 15 y of operation and several thousand explosive shots later, PHERMEX has proven to be a very important diagnostic tool in the study of hydrodynamic systems. The attractive features of PHERMEX are the following: very intense submicrosecond 27-MeV bremsstrahlung radiation; 1-mm diam spot size; 100 R at 1 m from a 200-ns pulse; precise determination of edges, discontinuities, and areal mass distribution; and flash radiographs of large explosive systems close to the target

  6. 10 CFR 34.46 - Supervision of radiographers' assistants.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Supervision of radiographers' assistants. 34.46 Section 34... REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Radiation Safety Requirements § 34.46 Supervision of... personal supervision of a radiographer. The personal supervision must include: (a) The radiographer's...

  7. On the definition of discrete hydrodynamic variables

    Science.gov (United States)

    Español, Pep; Zúñiga, Ignacio

    2009-10-01

    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.

  8. Retreatment or radiographic monitoring in endodontics.

    Science.gov (United States)

    Van Nieuwenhuysen, J P; Aouar, M; D'Hoore, W

    1994-03-01

    The aim of this clinical study was to assess 1032 endodontically treated roots in relation to: (i) the success rate of retreatment (612 roots)--only cases that had recall examinations of 6 months or longer were evaluated; (ii) the influence of various factors on the technical and clinical results of the retreatment; and (iii) the consequences of radiographic monitoring of 420 asymptomatic roots when the root filling was radiographically deficient (short, overextended and/or permeable root fillings). Technical assessment of the retreatment showed that the root was adequately sealed in 52.3% of cases, the root filling was improved in 33.8%, was identical with the initial treatment in 11.1% and was worse than the first treatment in 2.8% of the canals. Clinical assessment of the retreatment of symptomatic roots showed that 71.8% of the retreatments were judged successful, 18.9% showed some healing and 9.3% had failed. The initial size of the periapical lesion, the use of rubber dam, the root filling technique and the apical level of the root filling had a statistically significant influence on the result of the retreatment. Monitoring radiographically (median time span 6 years) led to maintenance of the status quo in 94.8% of cases, healing in 2.4% and failure in 2.8% of the canals. Retreatment is clearly indicated when periapical radiolucency, clinical signs and/or symptoms are present with relative success of up to 91%. When no or little radiographic evidence of periapical pathology was present, when clinical signs and symptoms were absent or when the root filling was radiographically deficient, radiographic monitoring led to complications in only a limited number of cases. clinical decision, endodontic retreatment, radiographic evaluation.

  9. Chest radiograph interpretation by medical students

    International Nuclear Information System (INIS)

    Jeffrey, D.R.; Goddard, P.R.; Callaway, M.P.; Greenwood, R.

    2003-01-01

    AIM: To assess the ability of final year medical students to interpret conventional chest radiographs. MATERIALS AND METHODS: Ten conventional chest radiographs were selected from a teaching hospital radiology department library that were good radiological examples of common conditions. All were conditions that a medical student should be expected to recognize by the end of their training. One normal radiograph was included. The radiographs were shown to 52 final year medical students who were asked to describe their findings. RESULTS: The median score achieved was 12.5 out of 20 (range 6-18). There was no difference between the median scores of male and female students (12.5 and 12.3, respectively, p=0.82) but male students were more likely to be certain of their answers than female students (median certainty scores 23.0 and 14.0, respectively). The overall degree of certainty was low. On no radiograph were more than 25% of students definite about their answer. Students had received little formal radiology teaching (2-42 h, median 21) and few expressed an interest in radiology as a career. Only two (3.8%) students thought they were good at interpreting chest radiographs, 17 (32.7%) thought they were bad or awful. CONCLUSION: Medical students reaching the end of their training do not perform well at interpreting simple chest radiographs. They lack confidence and have received little formal radiological tuition. Perhaps as a result, few are interested in radiology as a career, which is a matter for concern in view of the current shortage of radiologists in the UK

  10. Angles measuring on radiographic images as a tool for the diagnosis of Blount disease

    International Nuclear Information System (INIS)

    Mora Rojas, Raul

    2010-01-01

    The etiology of Blount disease has followed unknown at the present; although are described factors that could be related to the appearance of the same. Even, to make the diagnosis of this disease remains a challenge, due to it difficult to predict the behavior of the tibia varus in young children. Some measures were described in the radiographs of patients with tibia vara (the most currently used has been the Tibial Proximal Diaphyseal Goal Angle) to try to provide another tool in the diagnosis, but without be able to establish a free relationship between disruption of these measures with the pathological development of tibial varus. A new measurement (Tibial Proximal Fibular Mechanic Angle) established in the radiographs has been the purpose, taking into account the structures and concepts that are altered in patients with Blount diseases. The proximal tibial physis and the mechanical axis of the tibia are performed without to take into account in some of the measurements described above. (author) [es

  11. Femoral rotation unpredictably affects radiographic anatomical lateral distal femoral angle measurements

    DEFF Research Database (Denmark)

    Miles, James Edward

    2016-01-01

    Objective: To describe the effects of internal and external femoral rotation on radiographic measurements of the anatomical lateral distal femoral angle (a-LDFA) using two methods for defining the anatomical proximal femoral axis (a-PFA). Methods: Digital radiographs were obtained of 14 right...... femora at five degree intervals from 10° external rotation to 10° internal rotation. Using freely available software, a-LDFA measurements were made using two different a-PFA by a single observer on one occasion. Results: Mean a-LDFA was significantly greater at 10° external rotation than at any other...... rotation. The response of individual femora to rotation was unpredictable, although fairly stable within ±5° of zero rotation. Mean a-LDFA for the two a-PFA methods differed by 1.5°, but were otherwise similarly affected by femoral rotation. Clinical significance: If zero femoral elevation can be achieved...

  12. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

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

    2013-01-01

    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 f......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...... 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....

  13. Development of hydrodynamic micro-bearings

    Science.gov (United States)

    Wang, P.; Zhang, J.; Spikes, H. A.; Reddyhoff, T.; Holmes, A. S.

    2016-11-01

    This paper describes the modelling and testing of mm-scale hydrodynamic bearings which are being developed to improve the efficiency of a cm-scale turbine energy harvester, whose efficiency was previously limited by poorly lubricated commercial jewel-bearings. The bearings were fabricated using DRIE and their performance was assessed using a custom built MEMS tribometer. Results demonstrate that acceptably low friction is achieved when low viscosity liquid lubricants are used in combination with an appropriate choice of friction modifier additive. Further reduction in friction is demonstrated when the step height of bearing is adjusted in accordance with hydrodynamic theory. In parallel with the experiments, hydrodynamic lubricant modelling has been carried out to predict and further optimize film thickness and friction performance. Modelling results are presented and validated against experimental friction data.

  14. Hydrodynamic size and charge of polyelectrolyte complexes.

    Science.gov (United States)

    Böhme, Ute; Scheler, Ulrich

    2007-07-26

    Polyelectrolyte complexes have a wide range of applications for surface modification and flocculation and sorption of organic molecules from solutions. As an example, complexes between poly(diallyl dimethyl ammonium chloride) and poly(styrene sulfonate) have been investigated by diffusion and electrophoresis NMR. The formation of primary or soluble complexes is monitored. The hydrodynamic size is characterized by the hydrodynamic radius, calculated from the diffusion coefficient determined by pulsed field gradient NMR. In the combination with electrophoresis NMR, the effective charge of the molecules and complexes is determined. The hydrodynamic size of the primary complex is smaller than that of the pure polyelectrolyte of the larger molecular weight, in the present case poly(styrene sulfonate), in solution, since charges are compensated by the oppositely charged polyelectrolyte and hence the repelling forces diminish. The effective charge of the complexes is drastically reduced.

  15. The RAGE radiation-hydrodynamic code

    Energy Technology Data Exchange (ETDEWEB)

    Gittings, Michael; Clover, Michael; Betlach, Thomas; Byrne, Nelson; Ranta, Dale [Science Applications International Corp. MS A-1, 10260 Campus Point Drive, San Diego, CA 92121 (United States); Weaver, Robert; Coker, Robert; Dendy, Edward; Hueckstaedt, Robert; New, Kim; Oakes, W Rob [Los Alamos National Laboratory, MS T087, PO Box 1663, Los Alamos, NM 87545 (United States); Stefan, Ryan [TaylorMade-adidas Golf, 5545 Fermi Court, Carlsbad, CA 92008-7324 (United States)], E-mail: michael.r.clover@saic.com

    2008-10-01

    We describe RAGE, the 'radiation adaptive grid Eulerian' radiation-hydrodynamics code, including its data structures, its parallelization strategy and performance, its hydrodynamic algorithm(s), its (gray) radiation diffusion algorithm, and some of the considerable amount of verification and validation efforts. The hydrodynamics is a basic Godunov solver, to which we have made significant improvements to increase the advection algorithm's robustness and to converge stiffnesses in the equation of state. Similarly, the radiation transport is a basic gray diffusion, but our treatment of the radiation-material coupling, wherein we converge nonlinearities in a novel manner to allow larger timesteps and more robust behavior, can be applied to any multi-group transport algorithm.

  16. The RAGE radiation-hydrodynamic code

    International Nuclear Information System (INIS)

    Gittings, Michael; Clover, Michael; Betlach, Thomas; Byrne, Nelson; Ranta, Dale; Weaver, Robert; Coker, Robert; Dendy, Edward; Hueckstaedt, Robert; New, Kim; Oakes, W Rob; Stefan, Ryan

    2008-01-01

    We describe RAGE, the 'radiation adaptive grid Eulerian' radiation-hydrodynamics code, including its data structures, its parallelization strategy and performance, its hydrodynamic algorithm(s), its (gray) radiation diffusion algorithm, and some of the considerable amount of verification and validation efforts. The hydrodynamics is a basic Godunov solver, to which we have made significant improvements to increase the advection algorithm's robustness and to converge stiffnesses in the equation of state. Similarly, the radiation transport is a basic gray diffusion, but our treatment of the radiation-material coupling, wherein we converge nonlinearities in a novel manner to allow larger timesteps and more robust behavior, can be applied to any multi-group transport algorithm

  17. A systematic comparison of on-axis and off-axis transmission Kikuchi diffraction

    DEFF Research Database (Denmark)

    Niessen, F.; Burrows, A.; Fanta, A. Bastos da Silva

    2018-01-01

    Abstract The capabilities of the novel on-axis transmission Kikuchi diffraction (TKD) technique were explored in a systematic comparison with conventional off-axis TKD. The effect of experimental parameters on the appearance of on-axis and off-axis Kikuchi patterns was measured and discussed. In ...

  18. Radiographic testing - optimum radiographs of plastics and composite materials with dosimeter control

    International Nuclear Information System (INIS)

    Kuster, J.

    1978-01-01

    In view of great differencies in X-ray transmission it is more difficult to get optimum radiographs of plastics and especially of reinforced plastics than for example of metals. A procedure will be reported how to get with little effort optimum radiographs especially also in the range of long wavelength radiation corresponding 10 to 25 kV.P. (orig.) [de

  19. Australian rural radiographers' perspectives on disclosure of their radiographic opinion to patients

    International Nuclear Information System (INIS)

    Squibb, Kathryn; Bull, Rosalind M.; Smith, Anthony; Dalton, Lisa

    2015-01-01

    The role of Australian rural radiographers in radiographic interpretation, communication and disclosure of their radiographic opinion with a specific focus on plain film radiography was examined in a two phase, exploratory interpretive study. Data were collected using questionnaires and interviews and analysed thematically. This reports one of the key themes identified in the thematic data analysis. ‘Disclosure of Radiographic Opinion to Patients’ comprises the three interrelated sub-themes Acting Ethically, Selective Disclosure and Filtered Truth. It is wholly concerned with the ways in which rural radiographers choose to disclose their radiographic opinion to patients. Without a clear picture of where they stand medico-legally, rural radiographers draw on experience and a strong ethical framework as the basis for these complex decisions. Rural radiographers frame their disclosures to patients in a manner that is governed by the diagnostic, therapeutic and emotional impact the information disclosed may have on the patient. Disclosure to patients was found to be selective, often diagnostically vague and ethically filtered

  20. Measuring hindfoot alignment radiographically: the long axial view is more reliable than the hindfoot alignment view

    Energy Technology Data Exchange (ETDEWEB)

    Reilingh, Mikel L.; Beimers, Lijkele; Tuijthof, Gabrielle J.M.; Stufkens, Sjoerd A.S.; Dijk, C.N. van [Academic Medical Center, Department of Orthopaedic Surgery, Amsterdam (Netherlands); Maas, Mario [Academic Medical Center, Department of Radiology, Amsterdam (Netherlands)

    2010-11-15

    Hindfoot malalignment is a recognized cause of foot and ankle disability. For preoperative planning and clinical follow-up, reliable radiographic assessment of hindfoot alignment is important. The long axial radiographic view and the hindfoot alignment view are commonly used for this purpose. However, their comparative reliabilities are unknown. As hindfoot varus or valgus malalignment is most pronounced during mid-stance of gait, a unilateral weight-bearing stance, in comparison with a bilateral stance, could increase measurement reliability. The purpose of this study was to compare the intra- and interobserver reliability of hindfoot alignment measurements of both radiographic views in bilateral and unilateral stance. A hindfoot alignment view and a long axial view were acquired from 18 healthy volunteers in bilateral and unilateral weight-bearing stances. Hindfoot alignment was defined as the angular deviation between the tibial anatomical axis and the calcaneus longitudinal axis from the radiographs. Repeat measurements of hindfoot alignment were performed by nine orthopaedic examiners. Measurements from the hindfoot alignment view gave intra- and interclass correlation coefficients (CCs) of 0.72 and 0.58, respectively, for bilateral stance and 0.91 and 0.49, respectively, for unilateral stance. The long axial view showed, respectively, intra- and interclass CCs of 0.93 and 0.79 for bilateral stance and 0.91 and 0.58 for unilateral stance. The long axial view is more reliable than the hindfoot alignment view or the angular measurement of hindfoot alignment. Although intra-observer reliability is good/excellent for both methods, only the long axial view leads to good interobserver reliability. A unilateral weight-bearing stance does not lead to greater reliability of measurement. (orig.)

  1. Modeling of laser-driven hydrodynamics experiments

    Science.gov (United States)

    di Stefano, Carlos; Doss, Forrest; Rasmus, Alex; Flippo, Kirk; Desjardins, Tiffany; Merritt, Elizabeth; Kline, John; Hager, Jon; Bradley, Paul

    2017-10-01

    Correct interpretation of hydrodynamics experiments driven by a laser-produced shock depends strongly on an understanding of the time-dependent effect of the irradiation conditions on the flow. In this talk, we discuss the modeling of such experiments using the RAGE radiation-hydrodynamics code. The focus is an instability experiment consisting of a period of relatively-steady shock conditions in which the Richtmyer-Meshkov process dominates, followed by a period of decaying flow conditions, in which the dominant growth process changes to Rayleigh-Taylor instability. The use of a laser model is essential for capturing the transition. also University of Michigan.

  2. Impact of hydrodynamic stresses on bacterial flagella

    Science.gov (United States)

    Das, Debasish; Riley, Emily; Lauga, Eric

    2017-11-01

    The locomotion of bacteria powered by helical filaments, such as Escherichia coli, critically involves the generation of flows and hydrodynamic stresses which lead to forces and moments balanced by the moment applied by the bacterial rotary motor (which is embedded in the cell wall) and the deformation of the short flexible hook. In this talk we use numerical computations to accurately compute these hydrodynamic stresses, to show how they critically lead to fluid-structure instabilities at the whole-cell level, and enquire if they can be used to rationalise experimental measurements of bacterial motor torques. ERC Consolidator Grant.

  3. FDTD for Hydrodynamic Electron Fluid Maxwell Equations

    Directory of Open Access Journals (Sweden)

    Yingxue Zhao

    2015-05-01

    Full Text Available In this work, we develop a numerical method for solving the three dimensional hydrodynamic electron fluid Maxwell equations that describe the electron gas dynamics driven by an external electromagnetic wave excitation. Our numerical approach is based on the Finite-Difference Time-Domain (FDTD method for solving the Maxwell’s equations and an explicit central finite difference method for solving the hydrodynamic electron fluid equations containing both electron density and current equations. Numerical results show good agreement with the experiment of studying the second-harmonic generation (SHG from metallic split-ring resonator (SRR.

  4. Introduction to physics mechanics, hydrodynamics thermodynamics

    CERN Document Server

    Frauenfelder, P

    2013-01-01

    Introduction of Physics: Mechanics , Hydrodynamics, Thermodynamics covers the principles of matter and its motion through space and time, as well as the related concepts of energy and force. This book is composed of eleven chapters, and begins with an introduction to the basic principles of mechanics, hydrodynamics, and thermodynamics. The subsequent chapters deal with the statics of rigid bodies and the dynamics of particles and rigid bodies. These topics are followed by discussions on elasticity, mechanics of fluids, the basic concept of thermodynamic, kinetic theory, and crystal structure o

  5. Radiographic study on temporomandibular joint Arthrosis

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Dong Soo [Dept. of Radiology, College of Dentistry, Seoul National University , Seoul (Korea, Republic of)

    1980-11-15

    The author analysed the routine radiographic changes and clinical symptoms of 205 cases of temporomandibular joint arthrosis. The clinical symptoms of the patients were classified and the morphological changes of condylar head, articular eminence, and articular fossa were analyzed and discussed from radiographic view point. The positional change of condylar head and articular fossa relation in TMJ arthrosis were observed. The frequencies of coincidence between the site of complaints and the site of the abnormal images which could be detected were examined. The results were obtained as follows; 1. Bone erosion, deformity, marginal proliferation and sclerosis were selected from many abnormal images as the radiographic diagnostic criteria of TMJ arthritic lesions. 2. Abnormal radiographic findings were revealed in 150 cases (73.9%) of 205 total TMJ arthrosis cases and site with abnormal findings coincided with the site of complaints in 105 cases (70.7%) of 150 cases and coincidence rates were higher above fourth decades than below third decades. 3. Sclerosis of the abnormal radiographic findings could be found more often below third decades than above fourth decades. 4. The positional changes of condylar head were revealed in 176 cases (85.9%) of 205 total cases. 5. Pain complaints were revealed in 170 cases(82.9%) and clicking sounds were revealed in 120 cases (58.6%) of clinical symptoms of TMJ arthrosis. 6. No tendency was found so far the differential diagnosis between pain dysfunction syndrome and osteoarthrosis of TMJ.

  6. Radiographic study on temporomandibular joint Arthrosis

    International Nuclear Information System (INIS)

    Yoo, Dong Soo

    1980-01-01

    The author analysed the routine radiographic changes and clinical symptoms of 205 cases of temporomandibular joint arthrosis. The clinical symptoms of the patients were classified and the morphological changes of condylar head, articular eminence, and articular fossa were analyzed and discussed from radiographic view point. The positional change of condylar head and articular fossa relation in TMJ arthrosis were observed. The frequencies of coincidence between the site of complaints and the site of the abnormal images which could be detected were examined. The results were obtained as follows; 1. Bone erosion, deformity, marginal proliferation and sclerosis were selected from many abnormal images as the radiographic diagnostic criteria of TMJ arthritic lesions. 2. Abnormal radiographic findings were revealed in 150 cases (73.9%) of 205 total TMJ arthrosis cases and site with abnormal findings coincided with the site of complaints in 105 cases (70.7%) of 150 cases and coincidence rates were higher above fourth decades than below third decades. 3. Sclerosis of the abnormal radiographic findings could be found more often below third decades than above fourth decades. 4. The positional changes of condylar head were revealed in 176 cases (85.9%) of 205 total cases. 5. Pain complaints were revealed in 170 cases(82.9%) and clicking sounds were revealed in 120 cases (58.6%) of clinical symptoms of TMJ arthrosis. 6. No tendency was found so far the differential diagnosis between pain dysfunction syndrome and osteoarthrosis of TMJ.

  7. Radiographers' preconditions for evidence-based radiography

    International Nuclear Information System (INIS)

    Ahonen, Sanna-Mari; Liikanen, Eeva

    2010-01-01

    Evidence-based practice (EBP) is essential in today's health care, but its establishment requires several preconditions from individuals and organizations (e.g. knowledge, understanding, attitudes, abilities, self-confidence, support, and resources). Previous studies suggest that radiographers do generate and use evidence in their work, but evidence-based radiography (EBR) is not yet used routinely as established practice, especially in terms of research utilization. This paper aims to describe radiographers' preconditions for EBR, and their participation in research activities. Main focus is on research utilization. Using an electronic questionnaire developed for this study, a survey was conducted: data collected from Finnish radiographers and radiotherapists (N = 438) were analysed both statistically and qualitatively. The final response rate was 39%. The results suggest radiographers' preconditions for EBR to consist of knowledge of research, significance of research activities, research-orientated way of working, and support. In addition, adequate resourcing is essential. Reading scientific journals, participation in research activities, a higher degree of education, and senior post seem to be significant promoters of EBR and research utilization. The results support the notion that EBR, and especially research utilization, are not yet well-established in Finland, and radiographers' viewpoints concerning the role and significance of research evidence and research activities still seem to vary.

  8. Review on radiographic inspection in 1982

    International Nuclear Information System (INIS)

    Maruyama, Yutaka

    1983-01-01

    This is a report of the activities in the radiographic inspection department of Japanese Society for Non-destructive Inspection. The contents of activities are described about the following 15 items: standards, minimum discernible contrast and image distribution, contrast meter and penetrameter sensitivity, testing conditions, detection limit and simulation, photographing method for tube welding and corner welding, relationship between irradiation direction and flaw detectability, abnormal images, RI sources, X-ray equipment and observing device, sensitive materials, detectors, image processing and X-ray TV and automation, neutron radiography, other application and new techniques, and safety. Concerning the ''standards'', discussion was performed on revising JIS Z 3105 ''Methods of Radiographic Test and Classification of Radiographs for Aluminum Welds''. In ''Abnormal images'', the verification by the author that the abnormal shadows generated in the radiographic images of austenitic steel welded parts are the diffraction phenomenon to satisfy the Bragg's conditions is reported. In ''RI sources'', Yb-169 was found to be a good radiation source for relatively thin steel plates. In ''neutron radiography'', it was confirmed that the neutron radiography using a cyclotron as a neutron source can be used practically by its fundamental tests. ''Application and new techniques'' include a trial to utilize scattered radiation as a source, the testing method of γ shield for spent fuel transportation, the improvement of X-ray radiographic test for titanium thin plates and thin wall tubes, and others. (Wakatsuki, Y.)

  9. Radiographic anatomy of juvenile bovine limbs.

    Science.gov (United States)

    Hoey, S E; Biedrzycki, A H; Livesey, M J; Drees, R

    2016-11-26

    Juvenile bovine patients who present with clinical signs of lameness are commonly evaluated using radiographic techniques both within a hospital setting and in a farm environment. The radiographic development of the juvenile bovine skeleton is currently poorly documented. In this study, the limbs of four heifer calves were sequentially radiographed to assess development of the juvenile bovine appendicular skeleton in the first 12 months of life. Images were acquired at three weeks, three months, six months, nine months and one year of age. The normal radiographic anatomy of the fore limbs and hindlimbs and the changes over the first 12 months are described. The majority of physes remain open throughout this period, with the exception of the proximal physes of the proximal and middle phalanges, the proximal radial physis, and the proximal humeral physis which close radiographically between 9 months and 12 months of age, and fusion of the fourth and central tarsal bones occurs between 9 months and 12 months of age. The results of this study may aid in differentiating normal and abnormal anatomy in the juvenile bovine limb. British Veterinary Association.

  10. Radiographic abnormalities in tricyclic acid overdose

    International Nuclear Information System (INIS)

    Varnell, R.M.; Richardson, M.L.; Vincent, J.M.; Godwin, J.D.

    1987-01-01

    Several case reports have described adult respiratory distress syndrome (ARDS) secondary to tricyclic acid (TCA) overdose. During a 1-year period 83 patients requiring intubation secondary to drug overdose were evaluated. Abnormalities on chest radiographs occurred in 26 (50%) of the 54 patients with TCA overdose, compared to six (21%) of the 29 patients overdosed with other drugs. In addition, five (9%) of the patients with TCA overdose subsequently had radiographic and clinical abnormalities meeting the criteria for ARDS. Only one (3%) of the patients with non-TCA overdose subsequently had change suggesting ARDS. TCAs should be added to the list of drugs associated with ARDS, and TCA overdose should be considered a major risk factor in the development of radiographically evident abnormalities

  11. The review on radiographic inspection in 1978

    International Nuclear Information System (INIS)

    Furuta, Junichiro

    1979-01-01

    This is a review paper on the activities of radiographic inspection performed in 1978. The state of safety management in 1978 is reported. The JIS standards for the radiographic inspection were investigated. Problems concerning the measurement of the height of defects by non-destructive test were studied. The radiographic method with narrow irradiation field was developed. Radiography of the welded parts at corners, fiber reinforced plastics, offshore structures, nozzles, pipes and so on was investigated. Scattering ratio, contrast, and beam quality affect on identification, and these effects were studied. Defect-like patterns seen in X-ray graphs of cast metals and welded parts are due to X-ray diffraction. The relation between exposure and density of pictures was obtained as linear relation. The property of scattering ratio and an empirical formula were deduced. Development of instruments and films have been made. (Kato, T.)

  12. Initial image interpretation of appendicular skeletal radiographs: A comparison between nurses and radiographers

    International Nuclear Information System (INIS)

    Piper, Keith J.; Paterson, Audrey

    2009-01-01

    Purpose: To examine the effect of a short training programme on nurses and radiographers, exploring differences between their performance before and after training. Method: Twenty-two nurses and 18 radiographers interpreted 20 trauma radiographs of the appendicular skeleton before and after training. Normal and abnormal cases of a discriminatory nature were included. Total score, sensitivity and specificity values were calculated for each participant by comparison with an agreed expected answer. The area under the curve (AUC) was analysed using alternate free-response receiver operating characteristic (AFROC) methodology. Results: Significant differences were demonstrated between the total scores achieved by the two groups (pre-training: p = 0.007, post-training: p = 0.04). After training, the mean score increased significantly for both groups (p < 0.001). No significant difference was found between the radiographers mean pre-training scores and the nurses mean post-training scores (p = 0.66). Sensitivity for both groups increased following training, significantly so for the nurses (nurses: p < 0.001, radiographers: p = 0.06). Specificity reduced significantly after training for the nurses (p < 0.001), and increased for the radiographers but not significantly (p = 0.085). After training, there was no significant difference between the two groups in terms of sensitivity (p = 0.09) but specificity was significantly higher for the radiographers (p < 0.001). The radiographers achieved higher pre-training AUC values than the nurses (p = 0.04), although a difference remained after training this did not achieve statistical significance (p = 0.15). The AUC values increased significantly after training for both groups (nurses: p = 0.012, radiographers: p = 0.004) and again there was no significant difference between the radiographers pre-training performance and the nurses post-training performance (p = 0.62). Conclusion: Improvement after training was seen in both groups

  13. Radiographic indices for lumbar developmental spinal stenosis.

    Science.gov (United States)

    Cheung, Jason Pui Yin; Ng, Karen Ka Man; Cheung, Prudence Wing Hang; Samartzis, Dino; Cheung, Kenneth Man Chee

    2017-01-01

    Patients with developmental spinal stenosis (DSS) are susceptible to developing symptomatic stenosis due to pre-existing narrowed spinal canals. DSS has been previously defined by MRI via the axial anteroposterior (AP) bony spinal canal diameter. However, MRI is hardly a cost-efficient tool for screening patients. X-rays are superior due to its availability and cost, but currently, there is no definition of DSS based on plain radiographs. Thus, the aim of this study is to develop radiographic indices for diagnosing DSS. This was a prospective cohort of 148 subjects consisting of patients undergoing surgery for lumbar spinal stenosis (patient group) and asymptomatic subjects recruited openly from the general population (control group). Ethics approval was obtained from the local institutional review board. All subjects underwent MRI for diagnosing DSS and radiographs for measuring parameters used for creating the indices. All measurements were performed by two independent investigators, blinded to patient details. Intra- and interobserver reliability analyses were conducted, and only parameters with near perfect intraclass correlation underwent receiver operating characteristic (ROC) analysis to determine the cutoff values for diagnosing DSS using radiographs. Imaging parameters from a total of 66 subjects from the patient group and 82 asymptomatic subjects in the control group were used for analysis. ROC analysis suggested sagittal vertebral body width to pedicle width ratio (SBW:PW) as having the strongest sensitivity and specificity for diagnosing DSS. Cutoff indices for SBW:PW were level-specific: L1 (2.0), L2 (2.0), L3 (2.2), L4 (2.2), L5 (2.5), and S1 (2.8). This is the first study to define DSS on plain radiographs based on comparisons between a clinically relevant patient group and a control group. Individuals with DSS can be identified by a simple radiograph using a screening tool allowing for better cost-saving means for clinical diagnosis or research

  14. Radiographic indices for lumbar developmental spinal stenosis

    Directory of Open Access Journals (Sweden)

    Jason Pui Yin Cheung

    2017-02-01

    Full Text Available Abstract Background Patients with developmental spinal stenosis (DSS are susceptible to developing symptomatic stenosis due to pre-existing narrowed spinal canals. DSS has been previously defined by MRI via the axial anteroposterior (AP bony spinal canal diameter. However, MRI is hardly a cost-efficient tool for screening patients. X-rays are superior due to its availability and cost, but currently, there is no definition of DSS based on plain radiographs. Thus, the aim of this study is to develop radiographic indices for diagnosing DSS. Methods This was a prospective cohort of 148 subjects consisting of patients undergoing surgery for lumbar spinal stenosis (patient group and asymptomatic subjects recruited openly from the general population (control group. Ethics approval was obtained from the local institutional review board. All subjects underwent MRI for diagnosing DSS and radiographs for measuring parameters used for creating the indices. All measurements were performed by two independent investigators, blinded to patient details. Intra- and interobserver reliability analyses were conducted, and only parameters with near perfect intraclass correlation underwent receiver operating characteristic (ROC analysis to determine the cutoff values for diagnosing DSS using radiographs. Results Imaging parameters from a total of 66 subjects from the patient group and 82 asymptomatic subjects in the control group were used for analysis. ROC analysis suggested sagittal vertebral body width to pedicle width ratio (SBW:PW as having the strongest sensitivity and specificity for diagnosing DSS. Cutoff indices for SBW:PW were level-specific: L1 (2.0, L2 (2.0, L3 (2.2, L4 (2.2, L5 (2.5, and S1 (2.8. Conclusions This is the first study to define DSS on plain radiographs based on comparisons between a clinically relevant patient group and a control group. Individuals with DSS can be identified by a simple radiograph using a screening tool allowing for better

  15. Optimizing radiation exposure for CT localizer radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Bohrer, Evelyn; Maeder, Ulf; Fiebich, Martin [Univ. of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection-IMPS; Schaefer, Stefan; Krombach, Gabriele A. [Univ. Hospital Giessen (Germany). Dept. of Radiology; Noel, Peter B. [Technische Univ. Muenchen (Germany). Dept. of Diagnostic and Interventional Radiology

    2017-08-01

    The trend towards submillisievert CT scans leads to a higher dose fraction of localizer radiographs in CT examinations. The already existing technical capabilities make dose optimization of localizer radiographs worthwhile. Modern CT scanners apply automatic exposure control (AEC) based on attenuation data in such a localizer. Therefore not only this aspect but also the detectability of anatomical landmarks in the localizer for the desired CT scan range adjustment needs to be considered. The effective dose of a head, chest, and abdomen-pelvis localizer radiograph with standard factory settings and user-optimized settings was determined using Monte Carlo simulations. CT examinations of an anthropomorphic phantom were performed using multiple sets of acquisition parameters for the localizer radiograph and the AEC for the subsequent helical CT scan. Anatomical landmarks were defined to assess the image quality of the localizer. CTDI{sub vol} and effective mAs per slice of the helical CT scan were recorded to examine the impact of localizer settings on a helical CT scan. The dose of the localizer radiograph could be decreased by more than 90% while the image quality remained sufficient when selecting the lowest available settings (80 kVp, 20 mA, pa tube position). The tube position during localizer acquisition had a greater impact on the AEC than the reduction of tube voltage and tube current. Except for the use of a pa tube position, all changes of acquisition parameters for the localizer resulted in a decreased total radiation exposure. A dose reduction of CT localizer radiograph is necessary and possible. In the examined CT system there was no negative impact on the modulated helical CT scan when the lowest tube voltage and tube current were used for the localizer.

  16. Hydrodynamics: Fluctuating initial conditions and two-particle correlations

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, R.P.G.; Grassi, F. [Instituto de Fisica, Universidade de Sao Paulo (Brazil); Hama, Y., E-mail: hama@fma.if.usp.b [Instituto de Fisica, Universidade de Sao Paulo (Brazil); Qian, W.-L. [Instituto de Fisica, Universidade de Sao Paulo (Brazil)

    2011-03-15

    Event-by-event hydrodynamics (or hydrodynamics with fluctuating initial conditions) has been developed in the past few years. Here we discuss how it may help to understand the various structures observed in two-particle correlations.

  17. The one-leg standing radiograph

    OpenAIRE

    Pinsornsak, P.; 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 wa...

  18. Pelvic radiograph in skeletal dysplasias: An approach

    Directory of Open Access Journals (Sweden)

    Manisha Jana

    2017-01-01

    Full Text Available The bony pelvis is constituted by the ilium, ischium, pubis, and sacrum. The pelvic radiograph is an important component of the skeletal survey performed in suspected skeletal dysplasia. Most of the common skeletal dysplasias have either minor or major radiological abnormalities; hence, knowledge of the normal radiological appearance of bony pelvis is vital for recognizing the early signs of various skeletal dysplasias. This article discusses many common and some uncommon radiological findings on pelvic radiographs along with the specific dysplasia in which they are seen; common differential diagnostic considerations are also discussed.

  19. Pseudoprominent aorta: Radiographic findings and CT correlation

    International Nuclear Information System (INIS)

    Brown, K.T.; Shepard, J.A.O.; Stewart, W.J.

    1985-01-01

    The presence of a persistent left-sided superior vena cava (LSVC) in the absence of a right-sided superior vena cava (RSVC) may be suspected on a posteroanterior (PA) chest radiograph because of a prominent-appearing ascending aorta, which results from the absence of the RSVC. In the absence of an RSVC, the right upper lobe abuts and outlines the course of the ascending aorta, allowing better demonstration of its profile. This report describes a patient with this finding on a PA chest radiograph. Computed tomographic correlation is presented

  20. Pseudoprominent aorta: Radiographic findings and CT correlation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.T.; Shepard, J.A.O.; Stewart, W.J.

    1985-05-01

    The presence of a persistent left-sided superior vena cava (LSVC) in the absence of a right-sided superior vena cava (RSVC) may be suspected on a posteroanterior (PA) chest radiograph because of a prominent-appearing ascending aorta, which results from the absence of the RSVC. In the absence of an RSVC, the right upper lobe abuts and outlines the course of the ascending aorta, allowing better demonstration of its profile. This report describes a patient with this finding on a PA chest radiograph. Computed tomographic correlation is presented.

  1. [Assessment of radiographic investigation in discopathy diagnosis].

    Science.gov (United States)

    Samojedny, A; Guz, W

    1995-01-01

    Based on 262 radiographic examinations done during two years the authors have analyzed the compatibility of the radiographic image with the clinical examinations and with the operation results. In the analysis the most frequently occurring lesion level having the character of hernia of the nucleus pulposus, age, sex, and the duration of the disease symptoms were taken into account. The effectiveness of the method, which was verified by surgery was 86.3%. The result is in good agreement with literature data. Therefore, the method can be still recommended, particularly for the x-ray laboratories, which have no possibility to apply non-invasive techniques.

  2. Magnetic hydrodynamics with asymmetric stress tensor

    Science.gov (United States)

    Billig, Yuly

    2005-04-01

    In this paper we study equations of magnetic hydrodynamics with a stress tensor. We interpret this system as the generalized Euler equation associated with an Abelian extension of the Lie algebra of vector fields with a nontrivial 2-cocycle. We use the Lie algebra approach to prove the energy conservation law and the conservation of cross-helicity.

  3. Magnetic hydrodynamics with asymmetric stress tensor

    OpenAIRE

    Billig, Yuly

    2004-01-01

    In this paper we study equations of magnetic hydrodynamics with a stress tensor. We interpret this system as the generalized Euler equation associated with an abelian extension of the Lie algebra of vector fields with a non-trivial 2-cocycle. We use the Lie algebra approach to prove the energy conservation law and the conservation of cross-helicity.

  4. Microflow Cytometers with Integrated Hydrodynamic Focusing

    Directory of Open Access Journals (Sweden)

    Martin Schmidt

    2013-04-01

    Full Text Available This study demonstrates the suitability of microfluidic structures for high throughput blood cell analysis. The microfluidic chips exploit fully integrated hydrodynamic focusing based on two different concepts: Two-stage cascade focusing and spin focusing (vortex principle. The sample—A suspension of micro particles or blood cells—is injected into a sheath fluid streaming at a substantially higher flow rate, which assures positioning of the particles in the center of the flow channel. Particle velocities of a few m/s are achieved as required for high throughput blood cell analysis. The stability of hydrodynamic particle positioning was evaluated by measuring the pulse heights distributions of fluorescence signals from calibration beads. Quantitative assessment based on coefficient of variation for the fluorescence intensity distributions resulted in a value of about 3% determined for the micro-device exploiting cascade hydrodynamic focusing. For the spin focusing approach similar values were achieved for sample flow rates being 1.5 times lower. Our results indicate that the performances of both variants of hydrodynamic focusing suit for blood cell differentiation and counting. The potential of the micro flow cytometer is demonstrated by detecting immunologically labeled CD3 positive and CD4 positive T-lymphocytes in blood.

  5. does earthworms density really modify soil's hydrodynamic ...

    African Journals Online (AJOL)

    N. Ababsa,, M. Kribaa, D. Addad, L. Tamrabet and M. Baha

    1 mai 2016 ... Journal of Fundamental and Applied Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0. International License. Libraries Resource Directory. We are listed under Research Associations category. DOES EARTHWORMS DENSITY REALLY MODIFY SOIL'S HYDRODYNAMIC.

  6. PHANTOM: Smoothed particle hydrodynamics and magnetohydrodynamics code

    Science.gov (United States)

    Price, Daniel J.; Wurster, James; Nixon, Chris; Tricco, Terrence S.; Toupin, Stéven; Pettitt, Alex; Chan, Conrad; Laibe, Guillaume; Glover, Simon; Dobbs, Clare; Nealon, Rebecca; Liptai, David; Worpel, Hauke; Bonnerot, Clément; Dipierro, Giovanni; Ragusa, Enrico; Federrath, Christoph; Iaconi, Roberto; Reichardt, Thomas; Forgan, Duncan; Hutchison, Mark; Constantino, Thomas; Ayliffe, Ben; Mentiplay, Daniel; Hirsh, Kieran; Lodato, Giuseppe

    2017-09-01

    Phantom is a smoothed particle hydrodynamics and magnetohydrodynamics code focused on stellar, galactic, planetary, and high energy astrophysics. It is modular, and handles sink particles, self-gravity, two fluid and one fluid dust, ISM chemistry and cooling, physical viscosity, non-ideal MHD, and more. Its modular structure makes it easy to add new physics to the code.

  7. Hydrodynamic Lubrication Analysis Of Slider Bearings Lubricated ...

    African Journals Online (AJOL)

    Hydrodynamic Lubrication Analysis Of Slider Bearings Lubricated With Micropolar Fluids. ... In this paper, a theoretical study of the effect of micropolar lubricants on the performance characteristics of wide inclined slider bearings is presented. The finite element method and Gauss Seidel iterative procedure have been used ...

  8. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    This paper attempts to do that by critically reviewing published experimental and modelling studies on establishing and enhancing state-of-the-art thermodynamic, kinetic and hydrodynamic aspects of crystallization. Efforts are made to discuss and raise points for emerging modelling tools needed for a flexible design and ...

  9. Hydrodynamic relaxations in dissipative particle dynamics

    Science.gov (United States)

    Hansen, J. S.; Greenfield, Michael L.; Dyre, Jeppe C.

    2018-01-01

    This paper studies the dynamics of relaxation phenomena in the standard dissipative particle dynamics (DPD) model [R. D. Groot and P. B. Warren, J. Chem. Phys. 107, 4423 (1997)]. Using fluctuating hydrodynamics as the framework of the investigation, we focus on the collective transverse and longitudinal dynamics. It is shown that classical hydrodynamic theory predicts the transverse dynamics at relatively low temperatures very well when compared to simulation data; however, the theory predictions are, on the same length scale, less accurate for higher temperatures. The agreement with hydrodynamics depends on the definition of the viscosity, and here we find that the transverse dynamics are independent of the dissipative and random shear force contributions to the stress. For high temperatures, the spectrum for the longitudinal dynamics is dominated by the Brillouin peak for large length scales and the relaxation is therefore governed by sound wave propagation and is athermal. This contrasts the results at lower temperatures and small length scale, where the thermal process is clearly present in the spectra. The DPD model, at least qualitatively, re-captures the underlying hydrodynamical mechanisms, and quantitative agreement is excellent at intermediate temperatures for the transverse dynamics.

  10. Hydrodynamic states of phonons in insulators

    Directory of Open Access Journals (Sweden)

    S.A. Sokolovsky

    2012-12-01

    Full Text Available The Chapman-Enskog method is generalized for accounting the effect of kinetic modes on hydrodynamic evolution. Hydrodynamic states of phonon system of insulators have been studied in a small drift velocity approximation. For simplicity, the investigation was carried out for crystals of the cubic class symmetry. It has been found that in phonon hydrodynamics, local equilibrium is violated even in the approximation linear in velocity. This is due to the absence of phonon momentum conservation law that leads to a drift velocity relaxation. Phonon hydrodynamic equations which take dissipative processes into account have been obtained. The results were compared with the standard theory based on the local equilibrium validity. Integral equations have been obtained for calculating the objects of the theory (including viscosity and heat conductivity. It has been shown that in low temperature limit, these equations are solvable by iterations. Steady states of the system have been considered and an expression for steady state heat conductivity has been obtained. It coincides with the famous result by Akhiezer in the leading low temperature approximation. It has been established that temperature distribution in the steady state of insulator satisfies a condition of heat source absence.

  11. Stabilizing geometry for hydrodynamic rotary seals

    Science.gov (United States)

    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.

  12. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    understanding of the thermodynamic, kinetic and hydrodynamic aspects of the design methodologies are not yet well ...... The mixer design is finalized with mechanical design of the shaft, impeller blade thickness, baffle thickness and supports, ...... PhD-Thesis, Delft University of Technol- ogy, Delft. Dimonte J E, Szutowski H ...

  13. Magneto-hydrodynamical model for plasma

    Science.gov (United States)

    Liu, Ruikuan; Yang, Jiayan

    2017-10-01

    Based on the Newton's second law and the Maxwell equations for the electromagnetic field, we establish a new 3-D incompressible magneto-hydrodynamics model for the motion of plasma under the standard Coulomb gauge. By using the Galerkin method, we prove the existence of a global weak solution for this new 3-D model.

  14. Impact of Hydrodynamics on Oral Biofilm Strength

    NARCIS (Netherlands)

    Paramonova, E.; Kalmykowa, O. J.; van der Mei, H. C.; Busscher, H. J.; Sharma, P. K.

    2009-01-01

    Mechanical removal of oral biofilms is ubiquitously accepted as the best way to prevent caries and periodontal diseases. Removal effectiveness strongly depends on biofilm strength. To investigate the influence of hydrodynamics on oral biofilm strength, we grew single- and multi-species biofilms of

  15. An analytical model of flagellate hydrodynamics

    DEFF Research Database (Denmark)

    Dölger, Julia; Bohr, Tomas; Andersen, Anders Peter

    2017-01-01

    Flagellates are unicellular microswimmers that propel themselves using one or several beating flagella. We consider a hydrodynamic model of flagellates and explore the effect of flagellar arrangement and beat pattern on swimming kinematics and near-cell flow. The model is based on the analytical...

  16. Hydrodynamic forces on inundated bridge decks

    Science.gov (United States)

    2009-05-01

    The hydrodynamic forces experienced by an inundated bridge deck have great importance in the design of bridges. Specifically, the drag force, lift force, and the moment acting on the bridge deck under various levels of inundation and a range of flow ...

  17. Hydrodynamic simulations of the core helium flash

    Science.gov (United States)

    Mocák, Miroslav; Müller, Ewald; Weiss, Achim; Kifonidis, Konstantinos

    2008-10-01

    We desribe and discuss hydrodynamic simulations of the core helium flash using an initial model of a 1.25 M⊙ star with a metallicity of 0.02 near at its peak. Past research concerned with the dynamics of the core helium flash is inconclusive. Its results range from a confirmation of the standard picture, where the star remains in hydrostatic equilibrium during the flash (Deupree 1996), to a disruption or a significant mass loss of the star (Edwards 1969; Cole & Deupree 1980). However, the most recent multidimensional hydrodynamic study (Dearborn et al. 2006) suggests a quiescent behavior of the core helium flash and seems to rule out an explosive scenario. Here we present partial results of a new comprehensive study of the core helium flash, which seem to confirm this qualitative behavior and give a better insight into operation of the convection zone powered by helium burning during the flash. The hydrodynamic evolution is followed on a computational grid in spherical coordinates using our new version of the multi-dimensional hydrodynamic code HERAKLES, which is based on a direct Eulerian implementation of the piecewise parabolic method.

  18. Modified Artificial Viscosity in Smooth Particle Hydrodynamics

    OpenAIRE

    Selhammar, Magnus

    1996-01-01

    Artificial viscosity is needed in Smooth Particle Hydrodynamics to prevent interparticle penetration, to allow shocks to form and to damp post shock oscillations. Artificial viscosity may, however, lead to problems such as unwanted heating and unphysical solutions. A modification of the standard artificial viscosity recipe is proposed which reduces these problems. Some test cases discussed.

  19. Hydrodynamic erosion process of undisturbed clay

    NARCIS (Netherlands)

    Zhao, G.; Visser, P.J.; Vrijling, J.K.

    2011-01-01

    This paper describes the hydrodynamic erosion process of undisturbed clay due to the turbulent flow, based on theoretical analysis and experimental results. The undisturbed clay has the unique and complicated characteristics of cohesive force among clay particles, which are highly different from

  20. Symmetry Approach and Exact Solutions in Hydrodynamics

    OpenAIRE

    Golovin, Sergey V.

    2005-01-01

    The application of symmetry analysis in hydrodynamics is illustrated by two examples. First is a description of all irrotational barochronous motions of ideal gas. The second is an exact solution of magnetohydrodynamics equations for infinitely conducting media, which describes the flow of so called “special vortex” type.

  1. Hydrodynamics and Elasticity of Charged Black Branes

    DEFF Research Database (Denmark)

    Gath, Jakob

    We consider long-wavelength perturbations of charged black branes to first order in a uidelastic derivative expansion. At first order the perturbations decouple and we treat the hydrodynamic and elastic perturbations separately. To put the results in a broader perspective, we present the rst...

  2. The hydrodynamic description of pseudorapidity distributions at ...

    Indian Academy of Sciences (India)

    The hot and dense matter produced in nucleus–nucleus collisions is supposed to expand accordingto unified hydrodynamics, one of the few theoretical models that can be worked out exactly. The solutionis then used to formulate the rapidity distribution of charged particles frozen out from the fluid on thespace-like ...

  3. Hydrodynamic modelling of hydrostatic magnesium extrusion

    NARCIS (Netherlands)

    Moodij, Ellen; de Rooij, Matthias B.; Schipper, Dirk J.

    2006-01-01

    Wilson’s hydrodynamic model of the hydrostatic extrusion process is extended to meet the geometry found on residual billets. The transition from inlet to work zone of the process is not considered sharp as in the model of Wilson but as a rounded edge, modelled by a parabolic function. It is shown

  4. Hydrodynamic impact response, a flexible view

    NARCIS (Netherlands)

    Vredeveldt, A.W.; Hoogeland, M.; Janssen, G.Th.M.

    2001-01-01

    The popularity of high-speed craft is steadily increasing. Until now, much attention has been focussed on the hydrodynamic aspects of these craft. The structural design of these vessels is usually considered in a quasi static sense. However, due to the requirement of light ship structures, fast ship

  5. Hydrodynamic squeeze-film bearings for gyroscopes

    Science.gov (United States)

    Chiang, T.; Smith, R. L.

    1970-01-01

    Experimental tests are conducted on squeeze-film bearings by applying electricity to piezoelectric ceramics, causing vibrations at thousands or millions of Hz that are amplified and transmitted to the bearing. Rotor operation through 24,000 rpm without whirl instability proved bearing ability to support rotor weight without hydrodynamic action.

  6. Crystallization: Key thermodynamic, kinetic and hydrodynamic aspects

    Indian Academy of Sciences (India)

    In spite of the wide-spread use of crystallization, a clear understanding of the thermodynamic, kinetic and hydrodynamic aspects of the design methodologies are not yet well established. More often than not crystallization is still considered an art especially in fine-chemicals, pharmaceuticals and life-sciences sector.

  7. Hydrodynamic effects of nuclear active galaxy winds on host galaxies

    International Nuclear Information System (INIS)

    Schiano, A.V.R.

    1984-01-01

    In order to test the hypothesized existence of a powerful, thermal wind in active galactic nuclei, the hydrodynamic effects of such a wind on a model galactic interstellar medium (ISM) are investigated. The properties of several model ISMs are derived from observations of the Milky Way's ISM and those of nearby spiral and elliptical galaxies. The propagation of the wind into the low density gas component of the ISM is studied using the Kompaneets approximation of a strong explosion in an exponential atmosphere. Flattened gas distributions are shown to experience blow-out of wind gas along the symmetry axis. Next, the interaction of dense, interstellar clouds with the wind is investigated. The stability and mass loss of clouds in the wind are studied and it is proposed that clouds survive the encounter with the wind over large timescales. It is proposed that the narrow emission line regions (NELR) of active galaxies are the result of the interaction of active nuclei photons and a thermal wind on large, interstellar clouds

  8. A radiographic study of the position and shape of mental foramen in panoramic radiographs

    International Nuclear Information System (INIS)

    Choi, Karp Shik; Kim, Dong Youn; Sohn, Jeong Ick; Bae, Yong Chul

    1997-01-01

    The purpose of this study was to evaluate the position and shape of mental foramen in panoramic radiographs. For this study, panoramic radiographs were obtained from the 200 adults and evaluated the position and shape of mental foramen. According to various positional changes in panoramic radiographs of the patients, the author also obtained panoramic radiographs from the 100 adults and then evaluated the positional and shape changes of mental foramen. The following results were obtained : 1. Shapes of mental foramen were observed elliptical (43.3%), round or oval (42.5%), unidentified (7.5%) and diffuse (6.7%) type in descending order of frequency. 2. Horizontal position of mental foramen were most frequently observed at the 2nd premolar area (54.2%), and area between the 1st premolar and 2nd premolar (43.1%), area between the 2nd premolar and 1st molar (2.7%), and at apex (9.7%), overlap with apex (1.9%), superior of apex (0.2%) in descending order of frequency. 4. According to various positional changes in panoramic radiographs of the patients, shape changes of mental foramen were more obviously observed at the forward 10 mm and chin down 10 degree positioned panoramic radiographs, And changes of horizontal and vertical position were observed in similar to compared with normal positioned panoramic radiographs.

  9. A comparison of radiographer and radiologist reports on radiographer conducted barium enemas

    International Nuclear Information System (INIS)

    Murphy, M.; Loughran, C.F.; Birchenough, H.; Savage, J.; Sutcliffe, C.

    2002-01-01

    Purpose: To compare radiographer and radiologist reports on radiographer conducted barium enemas. Method: Two specially trained, experienced radiographers performed barium enemas and prepared provisional reports without consulting radiologists. Later, formal radiologist reports were issued. The reports of each were compared and correlated with clinical findings derived from case note review. Results:Seven hundred and eighty eight patients had barium enemas. Males numbered 295 (37.5%) and females 493 (62.5%). Patients ages ranged from 17 to 95 years (mean 62). The radiologist reported 244 as normal, 432 as diverticular change, 70 with polyps (31 of which had co-existent diverticular disease), 31 with carcinomas and 12 with colitis (three of which had co-existent diverticular disease). Taking the radiologist reports as gold-standard radiographer reports were concordant in 753 (95.5%). There were 35 (4.5%) discordant radiographer reports of these 19 were false-positive diagnoses of polyps and six false positive diagnoses of diverticular change. There were seven false-negative diagnoses of polyps (only one of these was found to have a polyp at follow-up endoscopy). There was one false-negative diagnosis of colitis and two false-negative reports of diverticular change. On follow up there were no false negative diagnoses of carcinoma by either radiographer or radiologist. There was one concordant false-positive diagnosis of carcinoma. Conclusion:Radiographers with specialized training can report barium enemas to a high standard

  10. A comparison of radiographer and radiologist reports on radiographer conducted barium enemas

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, M.; Loughran, C.F.; Birchenough, H.; Savage, J.; Sutcliffe, C

    2002-11-01

    Purpose: To compare radiographer and radiologist reports on radiographer conducted barium enemas. Method: Two specially trained, experienced radiographers performed barium enemas and prepared provisional reports without consulting radiologists. Later, formal radiologist reports were issued. The reports of each were compared and correlated with clinical findings derived from case note review. Results:Seven hundred and eighty eight patients had barium enemas. Males numbered 295 (37.5%) and females 493 (62.5%). Patients ages ranged from 17 to 95 years (mean 62). The radiologist reported 244 as normal, 432 as diverticular change, 70 with polyps (31 of which had co-existent diverticular disease), 31 with carcinomas and 12 with colitis (three of which had co-existent diverticular disease). Taking the radiologist reports as gold-standard radiographer reports were concordant in 753 (95.5%). There were 35 (4.5%) discordant radiographer reports of these 19 were false-positive diagnoses of polyps and six false positive diagnoses of diverticular change. There were seven false-negative diagnoses of polyps (only one of these was found to have a polyp at follow-up endoscopy). There was one false-negative diagnosis of colitis and two false-negative reports of diverticular change. On follow up there were no false negative diagnoses of carcinoma by either radiographer or radiologist. There was one concordant false-positive diagnosis of carcinoma. Conclusion:Radiographers with specialized training can report barium enemas to a high standard.

  11. A radiographic study of the position and shape of mental foramen in panoramic radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Karp Shik; Kim, Dong Youn; Sohn, Jeong Ick [Dept. of Dental Radiology, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of); Bae, Yong Chul [Dept. of Oral Anatomy, College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of)

    1997-02-15

    The purpose of this study was to evaluate the position and shape of mental foramen in panoramic radiographs. For this study, panoramic radiographs were obtained from the 200 adults and evaluated the position and shape of mental foramen. According to various positional changes in panoramic radiographs of the patients, the author also obtained panoramic radiographs from the 100 adults and then evaluated the positional and shape changes of mental foramen. The following results were obtained : 1. Shapes of mental foramen were observed elliptical (43.3%), round or oval (42.5%), unidentified (7.5%) and diffuse (6.7%) type in descending order of frequency. 2. Horizontal position of mental foramen were most frequently observed at the 2nd premolar area (54.2%), and area between the 1st premolar and 2nd premolar (43.1%), area between the 2nd premolar and 1st molar (2.7%), and at apex (9.7%), overlap with apex (1.9%), superior of apex (0.2%) in descending order of frequency. 4. According to various positional changes in panoramic radiographs of the patients, shape changes of mental foramen were more obviously observed at the forward 10 mm and chin down 10 degree positioned panoramic radiographs, And changes of horizontal and vertical position were observed in similar to compared with normal positioned panoramic radiographs.

  12. The radiographer's role in child protection: Comparison of radiographers perceptions by use of focus groups

    International Nuclear Information System (INIS)

    Davis, Michaela; Reeves, Pauline

    2006-01-01

    The research presented in this paper is taken from a larger study whose aims were to devise a holistic picture of how diagnostic radiographers approach child protection issues and to explore how radiographers and other professionals see the role of radiographers in the chain of evidence in relation to child protection as this applies to children who present at the Imaging Department with suspected non-accidental injuries (NAI). A focus group methodology was used with focus groups being conducted in the United Kingdom and Republic of Ireland. The results indicated that both United Kingdom and Republic of Ireland radiographers agreed that they had a role in child protection; however, they identified a wide interpretation as to the extent of that role. Although radiographers in the United Kingdom and Republic of Ireland work within different legal systems there were themes identified which were common to both countries. Although radiographers referred to a duty to the child as to all patients, no radiographer specifically mentioned the system and child care law under which it is assumed they operate. This research revealed an area which would benefit from more detailed research using a wider audience. However, the study revealed a need for training in relation to possible NAI indicators and the correct procedure for documenting their suspicions and initiating an NAI referral

  13. Assessment of hindfoot alignment using MRI and standing hindfoot alignment radiographs (Saltzman view)

    Energy Technology Data Exchange (ETDEWEB)

    Bueber, Nydia; Zanetti, Marco [Clinic Hirslanden, Department of Musculoskeletal Radiology, Zurich (Switzerland); Frigg, Arno [Clinic Hirslanden, Centre for Foot and Ankle Surgery, Zurich (Switzerland); Saupe, Nadja [Clinic Hirslanden, Department of Musculoskeletal Radiology, Zurich (Switzerland); Clinic Hirslanden Zurich, Department of Musculoskeletal Radiology, Zurich (Switzerland)

    2018-01-15

    To compare the hindfoot alignment measured on standing HAV radiographs (Saltzman view) and on non-weight-bearing coronal MR images. The apparent moment arm was measured on weight-bearing conventional radiographs (Saltzman views) and on MRIs of the ankle in 50 consecutive patients (mean age, 54 years; age range, 18-77 years). The evaluation was performed independently by three readers using analogous reference points for both methods. Positive values were assigned when the deepest point of the calcaneus was lateral to the tibial axis as valgus, negative values as varus. The intertechnique agreement and correlation for the measurements performed with HAV radiographs and MRI were assessed for each reader using the Bland-Altman method and the Pearson correlation coefficient, respectively. The interobserver agreement was assessed using the intraclass correlation coefficient. The means of apparent moment arms, with the standard deviation (SD) in parentheses, of three readers were +2.0 (±8.4) mm, +1.5 (±6.6) mm and -1.4 (±8.2) mm on HAV radiographs and +4.6 (±7.4) mm, +6.3 (±5.3) mm and +5.4 (±6.4) mm on MRI. The Bland-Altman analysis found a systematic bias for all three readers, corresponding to an overestimation of measurements with MRI (systematic bias ranging from 2.6 to 4.8 mm). The intertechnique correlation was found moderate to high. The Pearson coefficients for the three readers were 0.75, 0.64 and 0.65. The interobserver agreement among the three readers was 0.72, 0.77 and 0.68 for HAV, MRI and both modalities together, respectively. Hindfoot alignment can be estimated on MRI but the correlation between the values on HAV radiographs and MR images is only moderate with a tendency to increased positive values (valgization) on MR images. (orig.)

  14. Scaling supernova hydrodynamics to the laboratory

    International Nuclear Information System (INIS)

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

    1999-01-01

    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) and B. A. Remington et al., Phys. Plasmas 4, 1994 (1997)]. The Nova laser is used to generate a 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. This resembles the hydrodynamics of the He-H interface of a Type II supernova at intermediate times, up to a few x10 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. 51, 179 (1994)] and CALE [R. T. Barton, Numerical Astrophysics (Jones and Bartlett, Boston, 1985), pp. 482 - 497], and the supernova code PROMETHEUS [P. R. Woodward and P. Collela, J. Comp. Phys. 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

  15. Three-dimensional hindfoot alignment measurements based on biplanar radiographs: comparison with standard radiographic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, Reto; Pfirrmann, Christian W.A.; Buck, Florian M. [University Hospital Balgrist, Department of Radiology, Zurich (Switzerland); University of Zurich, Zurich (Switzerland); Espinosa, Norman [University Hospital Balgrist, Department of Orthopedic Surgery, Zurich (Switzerland); University of Zurich, Zurich (Switzerland)

    2013-04-15

    To establish a hindfoot alignment measurement technique based on low-dose biplanar radiographs and compare with hindfoot alignment measurements on long axial view radiographs, which is the current reference standard. Long axial view radiographs and low-dose biplanar radiographs of a phantom consisting of a human foot skeleton embedded in acrylic glass (phantom A) and a plastic model of a human foot in three different hindfoot positions (phantoms B1-B3) were imaged in different foot positions (20 internal to 20 external rotation). Two independent readers measured hindfoot alignment on long axial view radiographs and performed 3D hindfoot alignment measurements based on biplanar radiographs on two different occasions. Time for three-dimensional (3D) measurements was determined. Intraclass correlation coefficients (ICC) were calculated. Hindfoot alignment measurements on long axial view radiographs were characterized by a large positional variation, with a range of 14 /13 valgus to 22 /27 varus (reader 1/2 for phantom A), whereas the range of 3D hindfoot alignment measurements was 7.3 /6.0 to 9.0 /10.5 varus (reader 1/2 for phantom A), with a mean and standard deviation of 8.1 {+-} 0.6/8.7 {+-} 1.4 respectively. Interobserver agreement was high (ICC = 0.926 for phantom A, and ICC = 0.886 for phantoms B1-B3), and agreement between different readouts was high (ICC = 0.895-0.995 for reader 1, and ICC = 0.987-0.994 for reader 2) for 3D measurements. Mean duration of 3D measurements was 84 {+-} 15/113 {+-} 15 s for reader 1/2. Three-dimensional hindfoot alignment measurements based on biplanar radiographs were independent of foot positioning during image acquisition and reader independent. In this phantom study, the 3D measurements were substantially more precise than the standard radiographic measurements. (orig.)

  16. Radiographic interpretation of the appendicular skeleton: A comparison between casualty officers, nurse practitioners and radiographers

    International Nuclear Information System (INIS)

    Coleman, Liz; Piper, Keith

    2009-01-01

    Aim: To assess how accurately and confidently casualty officers, nurse practitioners and radiographers, practicing within the emergency department (ED), recognize and describe radiographic trauma within an image test bank of 20 appendicular radiographs. Method: The participants consisted of 7 casualty officers, 13 nurse practitioners and 18 radiographers. All 20 radiographic examinations selected for the image test bank had been acquired following trauma and included some subtle, yet clinically significant abnormalities. The test bank score (maximum 40 marks), sensitivity and specificity percentages were calculated against an agreed radiological diagnosis (reference standard). Alternative Free-response Receiver Operating Characteristic (AFROC) analysis was used to assess the overall performance of the diagnostic accuracy of these professional groups. The variation in performance between each group was measured using the analysis of variance (ANOVA) test, to identify any statistical significant differences in the performance in interpretation between these groups. The relationship between the participants' perceived image interpretation accuracy during clinical practice and the actual accuracy of their image test bank score was examined using Pearson's Correlation Coefficient (r). Results: The results revealed that the radiographers gained the highest mean test bank score (28.5/40; 71%). This score was statistically higher than the mean test bank scores attained by the participating nurse practitioners (21/40; 53%) and casualty officers (21.5/40; 54%), with p < 0.01 and p = 0.02, respectively. When compared with each other, the scores from these latter groups showed no significant difference (p = 0.91). The mean 'area under the curve' (AUC) value achieved by the radiographers was also significantly higher (p < 0.01) in comparison to the AUC values demonstrated by the nurse practitioners and casualty officers, whose results, when compared, showed no significant

  17. Radiographer commenting of trauma radiographs: a survey of the benefits, barriers and enablers to participation in an Australian healthcare setting

    International Nuclear Information System (INIS)

    Neep, Michael J.; Steffens, Tom; Owen, Rebecca; McPhail, Steven M.

    2014-01-01

    Radiographer abnormality detection systems that highlight abnormalities on trauma radiographs ('red dot' system) have been operating for more than 30 years. Recently, a number of pitfalls have been identified. These limitations initiated the evolution of a radiographer commenting system, whereby a radiographer provides a brief description of abnormalities identified in emergency healthcare settings. This study investigated radiographers' participation in abnormality detection systems, their perceptions of benefits, barriers and enablers to radiographer commenting, and perceptions of potential radiographer image interpretation services for emergency settings. A cross-sectional survey was implemented. Participants included radiographers from four metropolitan hospitals in Queensland, Australia. Conventional descriptive statistics, histograms and thematic analysis were undertaken. Seventy-three surveys were completed and included in the analysis (68% response rate); 30 (41%) of respondents reported participating in abnormality detection in 20% or less of examinations, and 26(36%) reported participating in 80% or more of examinations. Five overarching perceived benefits of radiographer commenting were identified: assisting multidisciplinary teams, patient care, radiographer ability, professional benefits and quality of imaging. Frequently reported perceived barriers included 'difficulty accessing image interpretation education', 'lack of time' and 'low confidence in interpreting radiographs'. Perceived enablers included 'access to image interpretation education' and 'support from radiologist colleagues'. A range of factors are likely to contribute to the successful implementation of radiographer commenting in addition to abnormality detection in emergency settings. Effective image interpretation education amenable to completion by radiographers would likely prove valuable in preparing radiographers for participation in abnormality detection and commenting systems in

  18. Large-Scale Description of Interacting One-Dimensional Bose Gases: Generalized Hydrodynamics Supersedes Conventional Hydrodynamics.

    Science.gov (United States)

    Doyon, Benjamin; Dubail, Jérôme; Konik, Robert; Yoshimura, Takato

    2017-11-10

    The theory of generalized hydrodynamics (GHD) was recently developed as a new tool for the study of inhomogeneous time evolution in many-body interacting systems with infinitely many conserved charges. In this Letter, we show that it supersedes the widely used conventional hydrodynamics (CHD) of one-dimensional Bose gases. We illustrate this by studying "nonlinear sound waves" emanating from initial density accumulations in the Lieb-Liniger model. We show that, at zero temperature and in the absence of shocks, GHD reduces to CHD, thus for the first time justifying its use from purely hydrodynamic principles. We show that sharp profiles, which appear in finite times in CHD, immediately dissolve into a higher hierarchy of reductions of GHD, with no sustained shock. CHD thereon fails to capture the correct hydrodynamics. We establish the correct hydrodynamic equations, which are finite-dimensional reductions of GHD characterized by multiple, disjoint Fermi seas. We further verify that at nonzero temperature, CHD fails at all nonzero times. Finally, we numerically confirm the emergence of hydrodynamics at zero temperature by comparing its predictions with a full quantum simulation performed using the NRG-TSA-abacus algorithm. The analysis is performed in the full interaction range, and is not restricted to either weak- or strong-repulsion regimes.

  19. Large-Scale Description of Interacting One-Dimensional Bose Gases: Generalized Hydrodynamics Supersedes Conventional Hydrodynamics

    Science.gov (United States)

    Doyon, Benjamin; Dubail, Jérôme; Konik, Robert; Yoshimura, Takato

    2017-11-01

    The theory of generalized hydrodynamics (GHD) was recently developed as a new tool for the study of inhomogeneous time evolution in many-body interacting systems with infinitely many conserved charges. In this Letter, we show that it supersedes the widely used conventional hydrodynamics (CHD) of one-dimensional Bose gases. We illustrate this by studying "nonlinear sound waves" emanating from initial density accumulations in the Lieb-Liniger model. We show that, at zero temperature and in the absence of shocks, GHD reduces to CHD, thus for the first time justifying its use from purely hydrodynamic principles. We show that sharp profiles, which appear in finite times in CHD, immediately dissolve into a higher hierarchy of reductions of GHD, with no sustained shock. CHD thereon fails to capture the correct hydrodynamics. We establish the correct hydrodynamic equations, which are finite-dimensional reductions of GHD characterized by multiple, disjoint Fermi seas. We further verify that at nonzero temperature, CHD fails at all nonzero times. Finally, we numerically confirm the emergence of hydrodynamics at zero temperature by comparing its predictions with a full quantum simulation performed using the NRG-TSA-abacus algorithm. The analysis is performed in the full interaction range, and is not restricted to either weak- or strong-repulsion regimes.

  20. Principles of the prolactin/vasoinhibin axis.

    Science.gov (United States)

    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. Copyright © 2015 the American Physiological Society.

  1. Acute injuries of the axis vertebra

    Energy Technology Data Exchange (ETDEWEB)

    Burke, J.T. (United General Hospital, Sedro Woolley, WA (USA)); Harris, J.H. (Texas Univ., Houston, TX (USA). Dept. of Radiology)

    1989-08-01

    A retrospective analysis of 165 patients admitted to Hermann Hospital with acute injuries of the axis vertebra revealed 68 (41%) dens fractures, 62 (38%) cases of traumatic spondylolisthesis ('hangman's' fracture), 21 (13%) extension teardrop fractures, 10 (6%) hyperextension dislocations, and 2 (1.0%) fractures each of the laminae and spinous processes. Of the axis injuries 31 (18%) were limited to the axis body alone. Of these, 21 (61%) were hyperextension teardrop fractures and 10 (32%) were hyperextension dislocations. Axis injuries were associated with acute injuries of other cervical vertebrae in 14 (8%) of the patients. (orig./GDG).

  2. Radiographic studies on morphological anomalies in artificially ...

    African Journals Online (AJOL)

    Radiographic examination revealed anomalies such as hypoplasia and hyperplasia of fins, supernumeracry and agenesis of fins, fin cleft, and fusion of fins, scoliosis and kyphosis. The phenotypic lateral body curvatures and stump body trait were basically due to varying degrees and positions of scoliosis and thus, ...

  3. Algorithms for boundary detection in radiographic images

    International Nuclear Information System (INIS)

    Gonzaga, Adilson; Franca, Celso Aparecido de

    1996-01-01

    Edge detecting techniques applied to radiographic digital images are discussed. Some algorithms have been implemented and the results are displayed to enhance boundary or hide details. An algorithm applied in a pre processed image with contrast enhanced is proposed and the results are discussed

  4. Radiographic analysis of pasteurized autologous bone graft

    International Nuclear Information System (INIS)

    Ahmed, Adel Refaat; Manabe, Jun; Kawaguchi, Noriyoshi; Matsumoto, Seiichi; Matsushita, Yasushi

    2003-01-01

    Local malignant bone tumor excision followed by pasteurization and subsequent reimplantation is a unique technique for reconstruction after resection of primary bone sarcomas. The purpose of this investigation was to assess the normal and abnormal long-term radiographic findings of intercalary and osteo-chondral pasteurized bone graft/implant composite. The long-term radiographic findings of pasteurized bone grafts used in reconstruction after resection of bone and soft tissue sarcomas in relation to patients' clinical data were reviewed retrospectively. Thirty-one patients (18 females, 13 males; age range 7-77 years, mean 30 years) who underwent surgery between April 1990 and January 1997 at the authors' institute constituted the material of this study. They were followed up for at least 3 years or until the patient's death (mean 69 months). The International Society of Limb Salvage graft evaluation method that assesses the fusion, resorption, fracture, graft shortening, fixation, subluxation, joint narrowing and subchondral bone was used for evaluation of the radiographs. Twenty-one patients (68%) showed complete incorporation of graft and eight patients (26%) had partial incorporation. The overall radiographic evaluation rate was 81%. Fracture (10%) and infection (16%) were the main complications. No local recurrence was detected. These results indicate that pasteurization of bone is a useful option for reconstruction after resection of malignant bone tumors. (orig.)

  5. Radiographic analysis of pasteurized autologous bone graft.

    Science.gov (United States)

    Ahmed, Adel Refaat; Manabe, Jun; Kawaguchi, Noriyoshi; Matsumoto, Seiichi; Matsushita, Yasushi

    2003-08-01

    Local malignant bone tumor excision followed by pasteurization and subsequent reimplantation is a unique technique for reconstruction after resection of primary bone sarcomas. The purpose of this investigation was to assess the normal and abnormal long-term radiographic findings of intercalary and osteo-chondral pasteurized bone graft/implant composite. The long-term radiographic findings of pasteurized bone grafts used in reconstruction after resection of bone and soft tissue sarcomas in relation to patients' clinical data were reviewed retrospectively. Thirty-one patients (18 females, 13 males; age range 7-77 years, mean 30 years) who underwent surgery between April 1990 and January 1997 at the authors' institute constituted the material of this study. They were followed up for at least 3 years or until the patient's death (mean 69 months). The International Society of Limb Salvage graft evaluation method that assesses the fusion, resorption, fracture, graft shortening, fixation, subluxation, joint narrowing and subchondral bone was used for evaluation of the radiographs. Twenty-one patients (68%) showed complete incorporation of graft and eight patients (26%) had partial incorporation. The overall radiographic evaluation rate was 81%. Fracture (10%) and infection (16%) were the main complications. No local recurrence was detected. These results indicate that pasteurization of bone is a useful option for reconstruction after resection of malignant bone tumors.

  6. Radiographic analysis of pasteurized autologous bone graft

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Adel Refaat [Department of Orthopedic Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Kamiikebukuro 1-37-1, Toshima-ku, 170-0012, Tokyo (Japan); Department of Orthopedic Surgery, Alexandria University, Alexandria (Egypt); Manabe, Jun; Kawaguchi, Noriyoshi; Matsumoto, Seiichi; Matsushita, Yasushi [Department of Orthopedic Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Kamiikebukuro 1-37-1, Toshima-ku, 170-0012, Tokyo (Japan)

    2003-08-01

    Local malignant bone tumor excision followed by pasteurization and subsequent reimplantation is a unique technique for reconstruction after resection of primary bone sarcomas. The purpose of this investigation was to assess the normal and abnormal long-term radiographic findings of intercalary and osteo-chondral pasteurized bone graft/implant composite. The long-term radiographic findings of pasteurized bone grafts used in reconstruction after resection of bone and soft tissue sarcomas in relation to patients' clinical data were reviewed retrospectively. Thirty-one patients (18 females, 13 males; age range 7-77 years, mean 30 years) who underwent surgery between April 1990 and January 1997 at the authors' institute constituted the material of this study. They were followed up for at least 3 years or until the patient's death (mean 69 months). The International Society of Limb Salvage graft evaluation method that assesses the fusion, resorption, fracture, graft shortening, fixation, subluxation, joint narrowing and subchondral bone was used for evaluation of the radiographs. Twenty-one patients (68%) showed complete incorporation of graft and eight patients (26%) had partial incorporation. The overall radiographic evaluation rate was 81%. Fracture (10%) and infection (16%) were the main complications. No local recurrence was detected. These results indicate that pasteurization of bone is a useful option for reconstruction after resection of malignant bone tumors. (orig.)

  7. Cold neutron radiographic apparatus and method

    International Nuclear Information System (INIS)

    Larsen, J.E.

    1979-01-01

    An improved cold neutron radiographic apparatus and method are disclosed wherein neutron temperature is matched to the specific material to be examined. This can be done, in one embodiment, by placing a radioactive source of neutrons, such as californium-252, in a moderator such as solid methane and using a cryogenic refrigeration system to cool the moderator to any preselected cryogenic temperature

  8. Radiographic analysis of ameloblastoma: A retrospective study

    Directory of Open Access Journals (Sweden)

    Chandramani More

    2012-01-01

    Conclusion: Radiographs are an important aid for the diagnosis of oral lesions of various types, especially those that involve bone. It is important for the practicing clinicians to know the salient features of ameloblastoma which are peculiar to the local population.

  9. Assessment of radiation protection practices among radiographers ...

    African Journals Online (AJOL)

    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 ...

  10. Unusual radiographic changes of a gout patient

    International Nuclear Information System (INIS)

    Markota, J.

    2004-01-01

    Background. Gout is a metabolic disorder that results in hyperuricemia and accumulation of uric acid crystals (urats) in tissues, especially joint cartilage. The gouty arthritis presents as acute attacks of arthritis leading eventually to chronic gouty arthritis. In 80% of cases it first occurs in the matatarsophalangeal (MTP) joint of the great toe and is more frequent in male population. Case report. We present a case of unusual radiographic changes accompanying gouty arthritis. A 63 year old female complained about swelling of the first MTP joint on the right, right knee, about stiffness of feet and hands' digits and about backache. First symptoms started to appear 30 years ago. In the time of examination radiographs displayed degenerative changes of the majority of presented joints, bilateral sacroiliitis and osseous ankylosis of both insteps. Microscopic examination showed urate crystals in the samples of the synovial fluid aspirated from the knee. The histological findings of the synovial tissue after the synovectomy were also in favour of gouty arthritis. Conclusions. Radiographs are the most important imaging modality in the diagnostic process of gout. However, radiographic differential diagnosis can be difficult, since the findings overlap with other conditions which cause arthritis and osteoarthritis especially in longstanding gout, elderly patients and females. The diagnosis must be often confirmed with the help of laboratory and histological findings. (author)

  11. Plain chest radiographic findings of smoke inhalation

    International Nuclear Information System (INIS)

    Lee, Shin Ho; Lee, Eil Weong; Kim, Hyun Suk; Park, Ju Youn; Kim, Soo Hyun; Hong, Sung Hwan; Park, Hong Suk; Lee, Kwan Seop; Kang Ik Won

    2000-01-01

    To evaluate the plain chest radiographic findings of smoke inhalation. Our study included 72 burn patients who had suffered smoke inhalation. On admission, all underwent serial portable chest AP radiography. We retrospectively reviewed the plain chest radiographs taken between admission and pootburn day five, evaluating the pattern, distribution, and time onset of direct injury to the respiratory system by smoke inhalation. The lesions were also assessed for change. In 16 of 72 patients (22%), abnormal findings of direct injury to the respiratory system by smoke inhalation were revealed by the radiographs. Abnormal findings were 15 pulmonary lesions and one subglottic tracheal narrowing. Findings of pulmonary lesions were multiple small patchy consolidations (10/15), peribronchial cuffing (8/15), and perivascular fuzziness (6/15). Patterns of pulmonary lesions were mixed alveolar and interstitial lesion (n=3D9), interstitial lesion (n=3D5), and alveolar lesion (n=3D1). No interlobular septal thickening was observed. Pulmonary edema was distributed predominantly in the upper lung zone and perihilar region, with asymmetricity. Its time of onset was within 24 hours in 13 cases, 24-48 hours in two cases, and 48-72 hours in one. Five of 16 patients progressed to ARDS. Chest radiographs showed that pulmonary lesions caused by inhalation injury were due to pulmonary edema, which the pattern of which was commonly mixed alveolar and interstitial. (author)

  12. Comparison of radiographic technique by computer simulation

    International Nuclear Information System (INIS)

    Brochi, M.A.C.; Ghilardi Neto, T.

    1989-01-01

    A computational algorithm to compare radiographic techniques (KVp, mAs and filters) is developed based in the fixation of parameters that defines the images, such as optical density and constrast. Before the experience, the results were used in a radiography of thorax. (author) [pt

  13. Radiographic and radionuclide findings in Rhizopus osteomyelitis

    Energy Technology Data Exchange (ETDEWEB)

    Moore, P.H. Jr.; McKinney, R.G.; Mettler, F.A. Jr.

    1978-06-01

    A case of Rhizopus osteromyelitis is described. The radionuclide and radiographic findings differ from those of osteomyelitis secondary to common pathogens: low-level radionuclide activity is observed, while soft-tissue swelling, periosteal reaction, and loss of fascial margins are absent.

  14. A Tutorial for Performing a Radiographic Examination

    Science.gov (United States)

    2017-03-01

    process in setting up, developing, documenting, and performing industrial radiography . The examples provided within this report are specific to the...equipment selection, (4) developing a technique , (5) verifying image quality, and (6) organizing proper documentation. Each section will provide...SUBJECT TERMS Radiography Munitions X-ray Nondestructive testing (NDT) Radiographic testing (RT) 16. SECURITY CLASSIFICATION

  15. Detecting objects in radiographs for homeland security

    Science.gov (United States)

    Prasad, Lakshman; Snyder, Hans

    2005-05-01

    We present a general scheme for segmenting a radiographic image into polygons that correspond to visual features. This decomposition provides a vectorized representation that is a high-level description of the image. The polygons correspond to objects or object parts present in the image. This characterization of radiographs allows the direct application of several shape recognition algorithms to identify objects. In this paper we describe the use of constrained Delaunay triangulations as a uniform foundational tool to achieve multiple visual tasks, namely image segmentation, shape decomposition, and parts-based shape matching. Shape decomposition yields parts that serve as tokens representing local shape characteristics. Parts-based shape matching enables the recognition of objects in the presence of occlusions, which commonly occur in radiographs. The polygonal representation of image features affords the efficient design and application of sophisticated geometric filtering methods to detect large-scale structural properties of objects in images. Finally, the representation of radiographs via polygons results in significant reduction of image file sizes and permits the scalable graphical representation of images, along with annotations of detected objects, in the SVG (scalable vector graphics) format that is proposed by the world wide web consortium (W3C). This is a textual representation that can be compressed and encrypted for efficient and secure transmission of information over wireless channels and on the Internet. In particular, our methods described here provide an algorithmic framework for developing image analysis tools for screening cargo at ports of entry for homeland security.

  16. Identifying murder victims with endodontic radiographs

    Science.gov (United States)

    Silva, Rhonan Ferreira; Franco, Ademir; Mendes, Solon Diego Santos Carvalho; Picoli, Fernando Fortes; Nunes, Fernando Gomes; Estrela, Carlos

    2016-01-01

    Endodontics is a special branch of dentistry constantly guided by imaging examinations. From a forensic scope, endodontics plays a valuable role providing solid antemortem (AM) radiographic evidence for comparison with postmortem findings in human identifications. This study illustrates the interface between endodontics and forensic odontology describing three cases of human identification based on radiographic endodontic records. From 2009 to 2012, three unknown male victims of murder were examined in a local Brazilian medico-legal institute to retrieve identity and potential cause of death. Specifically, when asked for AM data, a relative of the three victims provided periapical radiographs of endodontic treatments. Based on that, forensic dentists reproduced the same imaging acquisition techniques obtaining similar periapical radiographs, enabling a comparative dental identification. All the victims were positively identified based on patterns of dental morphology and treatment intervention. This study draws the attention of general and forensic dentists highlight the importance of properly recording dental treatments and searching for evidence in AM endodontic data, respectively. PMID:28123272

  17. Correlation Of Radiographic Patterns Of Pulmonary Tuberculosis ...

    African Journals Online (AJOL)

    Patients with higher CD4+ counts often present in \\"classic\\" fashion (upper zone infiltrates cavities) whereas those with low CD4+ counts are more likely to present atypically. The chest radiographic appearances of HIV-seropositive patients presenting with pulmonary tuberculosis (PTB) are diverse, creating difficulty in ...

  18. incidence of occupational stress among medical radiographers

    African Journals Online (AJOL)

    Summary: Biomechanical and Psychosocial stresses are capable of destabilizing any health care professional. The current health sector reform in Nigeria, which lays emphasis on service delivery on a background of very few radiographers, may lead to an increase in stress level. This study investigated the incidence of ...

  19. Thoracic radiographic anatomy in goats | Makungu | Tanzania ...

    African Journals Online (AJOL)

    . The aorta was not clearly visible on lateral views. The mean ratio of the CVC diameter to the height of the fourth thoracic vertebral body (T4) was 1.08 ± 0.07. Speciesspecific differences exist in the normal radiographic anatomy of the thorax.

  20. The glenohumeral offset ratio: A radiographic study.

    Science.gov (United States)

    Jacobson, S R; Mallon, W J

    1993-05-01

    A systematic method of component selection for total shoulder arthroplasty is needed. The method must take into account the soft-tissue constraints of a degenerative joint and optimize joint biomechanics by placing the joint line in the best possible position. The purpose of our study was to determine radiographically the normal glenohumeral joint line position based on a ratio of distances between the joint line and fixed landmarks on the humerus and scapula. We studied modified anteroposterior radiographs of the glenohumeral joint in 86 volunteers (51 men and 35 women; ages ranging from 21 to 47 years). Two measurements were made on each radiograph: (1) the perpendicular distance from the most medial portion of the glenoid to the inferior base of the coracoid process at its attachment to the scapular blade, and (2) the perpendicular distance from the midline of the humeral shaft to the most medial point on the humeral head. The joint line position was described as the ratio of the glenoid measurement to the sum of the two measurements (i.e., the glenohumeral offset ratio). The validity and reliability of glenoid offset measurements were determined by comparing radiographic and anatomic measurements of glenoid offset in cadaveric human scapulae. Radiographs were made with rotational error to determine its effects on the measurement of humeral offset. Humeral offsets and glenoid thicknesses of five different total shoulder systems were then determined from template overlays. The mean glenohumeral offset ratio was 0.31 (range 0.18 to 0.39). We detected no significant difference in the ratio between men and women volunteers. There was close agreement between radiographie and direct (anatomic) measurements of glenoid offset in cadaveric scapulae. Values for humeral offset were not significantly affected by radiographic rotational error. The evidence indicates that a fairly constant glenohumeral offset ratio in normal shoulders can be reliably calculated from a single

  1. An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine

    Directory of Open Access Journals (Sweden)

    Ridho Hantoro

    2011-04-01

    Full Text Available Vertical-axis hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Maximizing the turbine power output can be achieved only if the mechanism of generation of the hydrodynamic force on the blades is clearly identified and tools to design high-performance rotors are developed. This paper describes an initial experimental investigation to understand more of the performance on vertical-axis turbine related to the effect of fixed-pitch and passive variable-pitch application using airfoil NACA 0018. Comparative analysis according to aspects of rotation and tip speed ratios was discussed. Information regarding the changes of foil position in passive variable-pitch during rotation at a limited range of flow velocity variations test was obtained and analyzed.

  2. Image rejects/retakes--radiographic challenges.

    Science.gov (United States)

    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.

  3. Image rejects/retakes-radiographic challenges

    International Nuclear Information System (INIS)

    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

  4. Radiographic patterns of osteoporotic proximal humerus fractures.

    Science.gov (United States)

    Carbone, Stefano; Mezzoprete, Riccardo; Papalia, Matteo; Arceri, Valerio; Carbone, Andrea; Gumina, Stefano

    2018-03-01

    The objectives of the study were: a) to identify osteoporotic proximal humerus fractures in a large consecutive series of patients; b) to identify radiographic fracture patterns among osteoporotic and non-osteoporotic proximal humerus fractures; and c) to calculate intra- and inter-observer reliability of assessment of osteoporosis and of radiographic fracture patterns. This was a prospective observational study of patients admitted to the emergency department affected by a proximal humerus fracture between June 2014 and June 2016. Three researchers evaluated demographic data and comorbidities, x-rays and CT-scans. A new evaluation method for assessment of osteoporosis was proposed; 7 radiographic fracture patterns were studied. Reliabilities between intra- and inter-tester evaluations, and correlations between the presence of osteoporosis and the 7 radiologic fracture patterns were calculated. Two hundred twenty-five patients with a humeral fracture were recruited. Their mean (26-95, 32) age was 58. Of those, 163 (72.4%) were identified as osteoporotic. Among the three raters, the intra- and inter-observer agreement using the proposed methods were high or excellent. Significant correlations with diagnosis of osteoporosis were found with Codman-Lego type 12(p = 0.041), metaphyseal comminution(p patterns were high. Osteoporosis of the proximal humerus was identified in 72% of patients during a two year period; most of these patients were elderly females sustaining low energy trauma. These fractures showed to have specific radiographic patterns, as comminution of metaphysis and tuberosities, impaction of fragments, and inferior subluxation of the humeral head. These patterns can be assessed with the simple observation of a 2-plan view of a radiograph, without the use of specific software. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Predicting lower third molar eruption on panoramic radiographs after cephalometric comparison of profile and panoramic radiographs

    DEFF Research Database (Denmark)

    Begtrup, Anders; Grønastøð, Halldis Á; Christensen, Ib Jarle

    2012-01-01

    and to find a simple and reliable method for predicting the eruption of the mandibular third molar by measurements on panoramic radiographs. The material consisted of profile and panoramic radiographs, taken before orthodontic treatment, of 30 males and 23 females (median age 22, range 18-48 years......Previous studies have suggested methods for predicting third molar tooth eruption radiographically. Still, this prediction is associated with uncertainty. The aim of the present study was to elucidate the association between cephalometric measurements on profile and panoramic radiographs...... the length from the ramus to the incisors (olr-id) showed a statistically significant correlation. By combining this length with the mesiodistal width of the lower second molar, the prediction of eruption of the lower third molar was strengthened. A new formula for calculating the probability of eruption...

  6. Recognizing the radiographic features of some common bovine foot problems

    International Nuclear Information System (INIS)

    Ebeid, M.; Steiner, A.

    1996-01-01

    Radiographs of an injured or infected bovine foot can be tricky to interpret - the anatomy is complex, and the signs may be subtle. This guide leads you through the classic radiographic features of several common foot conditions

  7. Radiation doses of commonly used dental radiographic surveys.

    Science.gov (United States)

    Freeman, J P; Brand, J W

    1994-03-01

    The purpose of this study was to evaluate and to compare the radiation dose associated with commonly used dental radiographic surveys including the following: (1) 20 film full-mouth survey, (2) bite-wing radiographs, (3) panoramic survey supplemented with bite-wing radiographs and (4) a common orthodontic radiographic survey (a lateral cephlometric radiograph supplemented with a panoramic radiograph). The effects of collimation and faster radiographic film speeds on dose were also investigated. The effective doses to selected anatomic sites were calculated from measured absorbed doses with the use of an improved, tissue-equivalent phantom fitted with lithium fluoride thermoluminescent dosimeters. It was demonstrated that converting from round to rectangular collimation reduced the radiation exposure by a factor of four. A panoramic survey supplemented with bite-wing radiographs uses approximately one third of the radiation exposure needed to expose a full-mouth survey made with E-speed film and rectangular collimation.

  8. 2-D LSP Simulations of the Self Magnetic Pinch Radiographic Diode

    Science.gov (United States)

    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 ( 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.

  9. Radiographic visualization of magma dynamics in an erupting volcano

    OpenAIRE

    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 mag...

  10. Hydrodynamic properties of magnetic nanoparticles with tunable shape anisotropy: prediction and experimental verification.

    Science.gov (United States)

    Martchenko, Ilya; Dietsch, Hervé; Moitzi, Christian; Schurtenberger, Peter

    2011-12-15

    We describe the characterization of the hydrodynamic properties of anisotropic magnetic nanoparticles using a combination of transmission electron microscopy (TEM) and dynamic as well as depolarized dynamic light scattering (DLS/DDLS). The particles used are nearly monodisperse hematite spindles with an average length of 280 nm and a minor axis of 57 nm, coated with a layer of silica of variable thickness that allows us to tune the particle aspect ratio between 5 and 2. Their geometrical dimensions can thus be determined easily and quantitatively from TEM. Moreover, their size is ideal to employ DLS and DDLS to measure the translational and rotational diffusion coefficients D(T) and D(R), while the presence of a magnetic core opens a plethora of opportunities for future studies and applications. We demonstrate that we can successfully predict the hydrodynamic properties of the different particles based on a TEM characterization of their size distribution and using established theoretical models for the hydrodynamic properties of anisotropic particles. When compared with the theoretical predictions, our light scattering measurements are in quantitative agreement. This agreement between theory and experiment is achieved without having to invoke any adjustable free parameter, as the TEM results are used to calculate the corresponding diffusion coefficients on an absolute scale. We demonstrate that this is achieved due to a new and simple method for the statistical weighting of the TEM information, and the use of the correct hydrodynamic models for the observed particle shape. In addition, we also demonstrate an enhanced sensitivity of the rotational diffusion for the surface properties of ellipsoidal nanoparticles, and point out that this may serve as an ideal tool toward characterizing functionalized surfaces.

  11. The role of Weyl symmetry in hydrodynamics

    Science.gov (United States)

    Diles, Saulo

    2018-04-01

    This article is dedicated to the analysis of Weyl symmetry in the context of relativistic hydrodynamics. Here is discussed how this symmetry is properly implemented using the prescription of minimal coupling: ∂ → ∂ + ωA. It is shown that this prescription has no problem to deal with curvature since it gives the correct expressions for the commutator of covariant derivatives. In hydrodynamics, Weyl gauge connection emerges from the degrees of freedom of the fluid: it is a combination of the expansion and entropy gradient. The remaining degrees of freedom, shear, vorticity and the metric tensor, are see in this context as charged fields under the Weyl gauge connection. The gauge nature of the connection provides natural dynamics to it via equations of motion analogous to the Maxwell equations for electromagnetism. As a consequence, a charge for the Weyl connection is defined and the notion of local charge is analyzed generating the conservation law for the Weyl charge.

  12. Transversal expansion study in the Landau hydrodynamic

    International Nuclear Information System (INIS)

    Pottag, F.W.

    1984-01-01

    The system of equations in the frame of Landau's hydrodynamical model for multiparticle production at high energies is studied. Taking as a first approximation the one-dimensional exact due to Khalatnikov, and a special set of curvilinear coordinates, the radial part is separated from the longitudinal one in the equations of motion, and a system of partial differential equations (non-linear, hyperbolic) is obtained for the radial part. These equations are solved numerically by the method of caracteristics. The hydrodynamical variables are obtained over all the three-dimensional-flow region as well as its variation with the mass of the initially expanding system. Both, the transverse rapidity distribution of the fluid and the inclusive particle distribution at 90 0 in the center of mass system, are calculated. The last one is compared with recent experimental data. (author) [pt

  13. Heat capacity of liquids: A hydrodynamic approach

    Directory of Open Access Journals (Sweden)

    T. Bryk

    2015-03-01

    Full Text Available We study autocorrelation functions of energy, heat and entropy densities obtained by molecular dynamics simulations of supercritical Ar and compare them with the predictions of the hydrodynamic theory. It is shown that the predicted by the hydrodynamic theory single-exponential shape of the entropy density autocorrelation functions is perfectly reproduced for small wave numbers by the molecular dynamics simulations and permits the calculation of the wavenumber-dependent specific heat at constant pressure. The estimated wavenumber-dependent specific heats at constant volume and pressure, Cv(k and Cp(k, are shown to be in the long-wavelength limit in good agreement with the macroscopic experimental values of Cv and Cp for the studied thermodynamic points of supercritical Ar.

  14. Hydrodynamic models of a Cepheid atmosphere

    International Nuclear Information System (INIS)

    Karp, A.H.

    1974-11-01

    A method for including the solution of the transfer equation in a standard Henyey type hydrodynamic code was developed. This modified Henyey method was used in an implicit hydrodynamic code to compute deep envelope models of a classical Cepheid with a period of 12(d) including radiative transfer effects in the optically thin zones. It was found that the velocity gradients in the atmosphere are not responsible for the large microturbulent velocities observed in Cepheids but may be responsible for the occurrence of supersonic microturbulence. It was found that the splitting of the cores of the strong lines is due to shock induced temperature inversions in the line forming region. The adopted light, color, and velocity curves were used to study three methods frequently used to determine the mean radii of Cepheids. It is concluded that an accuracy of 10 percent is possible only if high quality observations are used. (auth)

  15. Fish stocking density impacts tank hydrodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Lunger, Angela; Laursen, Jesper

    2006-01-01

    The effect of stocking density upon the hydrodynamics of a circular tank, configured in a recirculation system, was investigated. Red drums Sciaenops ocellatus of approximately 140 g wet weight, were stocked at five rates varying from 0 to 12 kg m-3. The impact of the presence of fish upon tank...... hydrodynamics was established using in-tank-based Rhodamine WT fluorometry at a flow rate of 0.23 l s-1 (tank exchange rate of 1.9 h-1). With increasing numbers of animals, curvilinear relationships were observed for dispersion coefficients and tank mixing times. Stocking densities of 3, 6, 9 and 12 kg m-3...... resulted in a 0.2-, 0.5-, 2.4-, and 3.2-fold decrease in mixing time relative to that observed for empty tanks (Pb0.001)....

  16. Application of hydrodynamics to heavy ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Felsberger, Lukas

    2014-12-02

    The Bjorken model is a simple tool for making rough predictions of the hydrodynamic evolution of the thermalized matter created in a heavy ion collision. The advantage of the model clearly lies in its simplicity, rather than accuracy. As it is still used for making rough estimations 'by hand', in this thesis, I investigate in which cases the Bjorken model gives useful results and in which it is not recommended. For central collisions, I show which critical size the nuclei should have so that the Bjorken model can be applied. For non-central collisions, I demonstrate that using Glauber initial conditions combined with the Bjorken evolution, leads to reasonable results up to large impact parameters. Finally, I study the case of a non-ideal (viscous) description of the thermalized matter which leads to strongly differing results if first- or second-order hydrodynamics is applied.

  17. Solvable Hydrodynamics of Quantum Integrable Systems

    Science.gov (United States)

    Bulchandani, Vir B.; Vasseur, Romain; Karrasch, Christoph; Moore, Joel E.

    2017-12-01

    The conventional theory of hydrodynamics describes the evolution in time of chaotic many-particle systems from local to global equilibrium. In a quantum integrable system, local equilibrium is characterized by a local generalized Gibbs ensemble or equivalently a local distribution of pseudomomenta. We study time evolution from local equilibria in such models by solving a certain kinetic equation, the "Bethe-Boltzmann" equation satisfied by the local pseudomomentum density. Explicit comparison with density matrix renormalization group time evolution of a thermal expansion in the XXZ model shows that hydrodynamical predictions from smooth initial conditions can be remarkably accurate, even for small system sizes. Solutions are also obtained in the Lieb-Liniger model for free expansion into vacuum and collisions between clouds of particles, which model experiments on ultracold one-dimensional Bose gases.

  18. Solvable Hydrodynamics of Quantum Integrable Systems.

    Science.gov (United States)

    Bulchandani, Vir B; Vasseur, Romain; Karrasch, Christoph; Moore, Joel E

    2017-12-01

    The conventional theory of hydrodynamics describes the evolution in time of chaotic many-particle systems from local to global equilibrium. In a quantum integrable system, local equilibrium is characterized by a local generalized Gibbs ensemble or equivalently a local distribution of pseudomomenta. We study time evolution from local equilibria in such models by solving a certain kinetic equation, the "Bethe-Boltzmann" equation satisfied by the local pseudomomentum density. Explicit comparison with density matrix renormalization group time evolution of a thermal expansion in the XXZ model shows that hydrodynamical predictions from smooth initial conditions can be remarkably accurate, even for small system sizes. Solutions are also obtained in the Lieb-Liniger model for free expansion into vacuum and collisions between clouds of particles, which model experiments on ultracold one-dimensional Bose gases.

  19. Radiative and hydrodynamic growth of the fireball

    International Nuclear Information System (INIS)

    Stanic, B.V.; Skoric, M.M.; Aleksic, Z.

    1984-01-01

    The radiative and the hydrodynamic phases in development of the fireball, which form following an intense source of x-rays released in the atmosphere, are discussed. In the forst section, physical principles and simplified model of the fireball growth in the radiative phase are presented. The system of nonlinear differential equations which describes the time evolution of the fireball parameters (radius and temperature) in the radiation diffusion phase is numerically solved. A relation to some earlier work is outlined. In the second section, the later phase of the growth of the fireball is described by the equations of classical hydrodynamics. relevant parameters of the fireball (pressure and density at the surface of the fireball, radius and velocity of shock front) are estimated for two values of adiabatic constant. (author)

  20. Hydrodynamic interaction between bacteria and passive sphere

    Science.gov (United States)

    Zhang, Bokai; Ding, Yang; Xu, Xinliang

    2017-11-01

    Understanding hydrodynamic interaction between bacteria and passive sphere is important for identifying rheological properties of bacterial and colloidal suspension. Over the past few years, scientists mainly focused on bacterial influences on tracer particle diffusion or hydrodynamic capture of a bacteria around stationary boundary. Here, we use superposition of singularities and regularized method to study changes in bacterial swimming velocity and passive sphere diffusion, simultaneously. On this basis, we present a simple two-bead model that gives a unified interpretation of passive sphere diffusion and bacterial swimming. The model attributes both variation of passive sphere diffusion and changes of speed of bacteria to an effective mobility. Using the effective mobility of bacterial head and tail as an input function, the calculations are consistent with simulation results at a broad range of tracer diameters, incident angles and bacterial shapes.

  1. Hydrodynamics of ultra-relativistic bubble walls

    Directory of Open Access Journals (Sweden)

    Leonardo Leitao

    2016-04-01

    Full Text Available 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.

  2. Smoothed Particle Hydrodynamics Coupled with Radiation Transfer

    Science.gov (United States)

    Susa, Hajime

    2006-04-01

    We have constructed a brand-new radiation hydrodynamics solver based upon Smoothed Particle Hydrodynamics, which works on a parallel computer system. The code is designed to investigate the formation and evolution of first-generation objects at z ≳ 10, where the radiative feedback from various sources plays important roles. The code can compute the fraction of chemical species e, H+, H, H-, H2, and H+2 by by fully implicit time integration. It also can deal with multiple sources of ionizing radiation, as well as radiation at Lyman-Werner band. We compare the results for a few test calculations with the results of one-dimensional simulations, in which we find good agreements with each other. We also evaluate the speedup by parallelization, which is found to be almost ideal, as long as the number of sources is comparable to the number of processors.

  3. Resolution of hydrodynamical equations for transverse expansions

    International Nuclear Information System (INIS)

    Hama, Y.; Pottag, F.W.

    1984-01-01

    The three-dimensional hydrodynamical expansion is treated with a method similar to that of Milekhin, but more explicit. Although in the final stage one have to appeal to numerical calculation, the partial differential equations governing the transverse expansions are treated without transforming them into ordinary equations with an introduction of averaged quantities. It is only concerned with the formalism and the numerical results will be given in the next paper. (Author) [pt

  4. Numerical Hydrodynamics and Magnetohydrodynamics in General Relativity

    Directory of Open Access Journals (Sweden)

    Font José A.

    2008-09-01

    Full Text Available This article presents a comprehensive overview of numerical hydrodynamics and magnetohydrodynamics (MHD in general relativity. Some significant additions have been incorporated with respect to the previous two versions of this review (2000, 2003, most notably the coverage of general-relativistic MHD, a field in which remarkable activity and progress has occurred in the last few years. Correspondingly, the discussion of astrophysical simulations in general-relativistic hydrodynamics is enlarged to account for recent relevant advances, while those dealing with general-relativistic MHD are amply covered in this review for the first time. The basic outline of this article is nevertheless similar to its earlier versions, save for the addition of MHD-related issues throughout. Hence, different formulations of both the hydrodynamics and MHD equations are presented, with special mention of conservative and hyperbolic formulations well adapted to advanced numerical methods. A large sample of numerical approaches for solving such hyperbolic systems of equations is discussed, paying particular attention to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. As previously stated, a comprehensive summary of astrophysical simulations in strong gravitational fields is also presented. These are detailed in three basic sections, namely gravitational collapse, black-hole accretion, and neutron-star evolutions; despite the boundaries, these sections may (and in fact do overlap throughout the discussion. The material contained in these sections highlights the numerical challenges of various representative simulations. It also follows, to some extent, the chronological development of the field, concerning advances in the formulation of the gravitational field, hydrodynamics and MHD equations and the numerical methodology designed to solve them. To keep the length of this article reasonable

  5. On an incompressible model in radiation hydrodynamics

    Czech Academy of Sciences Publication Activity Database

    Ducomet, B.; Nečasová, Šárka

    2015-01-01

    Roč. 38, č. 4 (2015), s. 765-774 ISSN 0170-4214 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : radiation hydrodynamics * incompressible Navier - Stokes -Fourier system * weak solution Subject RIV: BA - General Mathematics Impact factor: 1.002, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/mma.3107/abstract

  6. On an incompressible model in radiation hydrodynamics

    Czech Academy of Sciences Publication Activity Database

    Ducomet, B.; Nečasová, Šárka

    2015-01-01

    Roč. 38, č. 4 (2015), s. 765-774 ISSN 0170-4214 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : radiation hydrodynamics * incompressible Navier-Stokes-Fourier system * weak solution Subject RIV: BA - General Mathematics Impact factor: 1.002, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/mma.3107/abstract

  7. Appearance of the mandibular incisive canal on panoramic radiographs

    NARCIS (Netherlands)

    Jacobs, R.; Mraiwa, N.; van Steenberghe, D.; Sanderink, G.C.H.; Quirynen, M.

    2004-01-01

    Panoramic radiographs are routinely used in the dental office for various diagnostic purposes. This study aimed to evaluate the visibility of neurovascular structures in the mandibular interforaminal region on such radiographs. Panoramic radiographs were obtained with a Cranex Tome (Soredex) from

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

    Science.gov (United States)

    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 to...

  9. The palmar metric: A novel radiographic assessment of the equine ...

    African Journals Online (AJOL)

    Digital radiographs are often used to subjectively assess the equine digit. Recently, quantitative and objective radiographic measurements have been reported that give new insight into the form and function of the equine digit. We investigated a radio-dense curvilinear profile along the distal phalanx on lateral radiographs ...

  10. 21 CFR 892.1960 - Radiographic intensifying screen.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic intensifying screen. 892.1960 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1960 Radiographic intensifying screen. (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet...

  11. Hydrodynamics of an Electrochemical Membrane Bioreactor

    Science.gov (United States)

    Wang, Ya-Zhou; Wang, Yun-Kun; He, Chuan-Shu; Yang, Hou-Yun; Sheng, Guo-Ping; Shen, Jin-You; Mu, Yang; Yu, Han-Qing

    2015-05-01

    An electrochemical membrane bioreactor (EMBR) has recently been developed for energy recovery and wastewater treatment. The hydrodynamics of the EMBR would significantly affect the mass transfers and reaction kinetics, exerting a pronounced effect on reactor performance. However, only scarce information is available to date. In this study, the hydrodynamic characteristics of the EMBR were investigated through various approaches. Tracer tests were adopted to generate residence time distribution curves at various hydraulic residence times, and three hydraulic models were developed to simulate the results of tracer studies. In addition, the detailed flow patterns of the EMBR were acquired from a computational fluid dynamics (CFD) simulation. Compared to the tank-in-series and axial dispersion ones, the Martin model could describe hydraulic performance of the EBMR better. CFD simulation results clearly indicated the existence of a preferential or circuitous flow in the EMBR. Moreover, the possible locations of dead zones in the EMBR were visualized through the CFD simulation. Based on these results, the relationship between the reactor performance and the hydrodynamics of EMBR was further elucidated relative to the current generation. The results of this study would benefit the design, operation and optimization of the EMBR for simultaneous energy recovery and wastewater treatment.

  12. Hydrodynamic Modeling of Santa Marta's Big Marsh

    International Nuclear Information System (INIS)

    Saldarriaga, Juan

    1991-01-01

    The ecological degradation of Santa Marta's Big Marsh and their next areas it has motivated the realization of diagnosis studies and design by several state and private entities. One of the recommended efforts for international advisory it was to develop an ecological model that allowed the handling of the water body and the economic test of alternative of solution to those ecological problems. The first part of a model of this type is in turn a model that simulates the movement of the water inside the marsh, that is to say, a hydrodynamic model. The realization of this was taken charge to the civil engineering department, on the part of Colciencias. This article contains a general explanation of the hydrodynamic pattern that this being developed by a professors group. The ecological causes are described and antecedent, the parts that conform the complex of the Santa Marta big Marsh The marsh modeling is made and it is explained in qualitative form the model type Hydrodynamic used

  13. Hydrodynamic slip length as a surface property

    Science.gov (United States)

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

    2016-02-01

    Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.

  14. Ex vivo radiographic tooth length measurements with the reference sphere method (RSM).

    Science.gov (United States)

    Roeder, Felix; Brüllmann, Dan; d'Hoedt, Bernd; Schulze, Ralf

    2010-12-01

    A reference-based radiographic "reference sphere method" (RSM) for accurate length measurements in (dental) projection radiographs for the assessment of tooth length in dry human mandible sections is evaluated. RSM determines the depth coordinates of reference spheres placed in the object plane from the elliptical distortion of their shadows. Two segments (one canine and one molar) of dry human mandibles were exposed 95 times at different angulations (0-40°) on a dental charge-coupled device receptor. Three steel spheres (diameters d (1) = 2.00 mm, d (2) = 3.00 mm) were attached roughly coplanar with the tooth's main axis. Radiographs were assessed once by visual inspection plus manual landmark identification with a mouse-driven cursor. The results were compared to the true tooth length assessed after extraction and to a conventional method (C), i.e., the rule of proportion based on magnification of the sphere shadows. Mean relative length error was 2.28% (d (1)) and 0.46% (d (2)) for RSM and -13.58% (d (1)) and -9.90% (d (2)) for C. For both methods, length errors were significantly (p correction of objects coplanar with the reference spheres. Remaining errors are mainly due to incorrect landmark definition. In our setup, these were exaggerated by the visual/manual image-evaluation process. Automated image analysis has been shown for similar tasks to minimize these errors considerably.

  15. Pediatric cervical spine in emergency: radiographic features of normal anatomy, variants and pitfalls

    Energy Technology Data Exchange (ETDEWEB)

    Adib, Omar; Berthier, Emeline; Loisel, Didier; Aube, Christophe [University Hospital of Angers, Department of Radiology, Angers (France)

    2016-12-15

    Injuries of the cervical spine are uncommon in children. The distribution of injuries, when they do occur, differs according to age. Young children aged less than 8 years usually have upper cervical injuries because of the anatomic and biomechanical properties of their immature spine, whereas older children, whose biomechanics more closely resemble those of adults, are prone to lower cervical injuries. In all cases, the pediatric cervical spine has distinct radiographic features, making the emergency radiological analysis of it difficult. Such features as hypermobility between C2 and C3, pseudospread of the atlas on the axis, pseudosubluxation, the absence of lordosis, anterior wedging of vertebral bodies, pseudowidening of prevertebral soft tissue and incomplete ossification of synchondrosis can be mistaken for traumatic injuries. The interpretation of a plain radiograph of the pediatric cervical spine following trauma must take into account the age of the child, the location of the injury and the mechanism of trauma. Comprehensive knowledge of the specific anatomy and biomechanics of the childhood spine is essential for the diagnosis of suspected cervical spine injury. With it, the physician can, on one hand, differentiate normal physes or synchondroses from pathological fractures or ligamentous disruptions and, on the other, identify any possible congenital anomalies that may also be mistaken for injury. Thus, in the present work, we discuss normal radiological features of the pediatric cervical spine, variants that may be encountered and pitfalls that must be avoided when interpreting plain radiographs taken in an emergency setting following trauma. (orig.)

  16. A study of the mandibular condyle shape on the individualized corrected the tomograph and submentovertex radiograph

    International Nuclear Information System (INIS)

    Lee, Sang Rae

    1994-01-01

    The purpose of this study was to observe mandibular condyle shape in an asymptomatic population. In order to carry out this study, 96 temporomandibular joints in 48 adults (22 males, 26 females), who were asymptomatic for temporomandibular disturbances and had no history of prosthodontic or orthodontic treatments, were selected, and radiographed using the Sectograph(Denar Co., U.S.A.) for lateral and frontal individualized corrected TMJ tomograph and submentovertex radiograph. Mandibular condyles were classified morphologically, and measured mediolateral and anteroposterior dimensions and condylar angulation. The obtained results were as follows. 1. In the classification of condyle shape on lateral tomographs, 94.8% were convex type and 5.2% were angled type. 2. In the classification of condyle shape on frontal tomographs, 45.3% were convex type, 32.0% were round type, 16.0% were flat type, and 6.7% were angled type. 3. In the classification of condyle shape on submentovertex radiographs, 34.5% were flat-convex type, 22.9% were flat-flat type, 20.8% were concave-convex type, 19.8% were convex-concave type, and flat-concave type were not observed. 4. The average mediolateral length of the condyle was 19.3 mm and the average anteroposterior length was 9.4 mm. The average angle between the long axis of condyle and the coronal plane made on submentovertex view was 19.6 degrees.

  17. Out of Axis Movement of an AUV inside a Water Pipeline

    Directory of Open Access Journals (Sweden)

    M. Moonesun

    2017-03-01

    Full Text Available The research intends to evaluate the variation in the resistance and the lift of a torpedo shaped AUV brought about by the wall effect inside the pipe as it moves out of the axis inside a water pipeline. Movement of an AUV at the axis of a pipe causes minimum resistance and lift forces, but when the AUV moves at a position parallel with the axis of the pipe (out of axis of the pipe, the hydrodynamic forces especially the lift force changes. The AUV must be able to move a float inside the pipe and perform non-contact inspection. In water pipes having limited diameters, there is the wall effect. The added resistance and the lift have to be calculated accurately, which is a necessary requirement for the determination of the vehicle speed, power demand, control, range and duration of the operation. According to the findings of this paper, when moving at the center of pipe the ratio of AUV diameter to pipe diameter is equal to 12. This value can be considered for the determination of "the critical pipe diameter" which gives zero resistance. The results of this study can be applied for torpedo movement inside the torpedo tube. The analysis is performed by the Flow Vision (V.2.3 software based on the CFD method and solving the RANS equations.

  18. Adaptive predictive coding with applications to radiographs.

    Science.gov (United States)

    Rabbani, M; Ray, L A; Sullivan, J R

    1986-01-01

    Picture archiving and communications systems (PACS) require storage and transmission of vast amounts of data. For design/cost considerations, it is desirable to reduce the size of these data without sacrificing the integrity of the stored information. The major considerations in designing a data-compression scheme for a PACS system are discussed: fidelity of the reconstructed image, bit rate, hardware complexity, and processing time. The basic principles of conventional nonadaptive differential pulse-code modulation (DPCM) are reviewed and compared with adaptive techniques. The effect of adaptive quantization on radiographic images is examined. Special consideration is given to block-adaptive DPCM or the "switched quantizer," which greatly enhances the system performance as compared with nonadaptive techniques, and conservatively has a 5:1 compression ratio. Sample radiographs substantiate the results.

  19. Mediastinal hemorrhage: An evaluation of radiographic manifestations

    Energy Technology Data Exchange (ETDEWEB)

    Woodring, J.H.; Loh, F.K.; Kryscio, R.J.

    1984-04-01

    Eleven common radiographic signs of mediastinal hemorrhage were evaluated by two observers for the following three patient groups: normal subjects, patients with mediastinal hemorrhage and no arterial injury, and patients with major thoracic arterial injury. Supine chest radiographs were studied in all cases. Four major conclusions can be made based upon these finding. M/C ratio (mediastinal width to chest width), tracheal deviation, left hemothorax, paraspinal line widening, and aorto-pulmonary window opacification do not reliably separate these three groups of patients. The diagnosis of mediastinal hemorrhage may be made if the aortic contour is abnormal or if one of the following signs is positive: abnormal mediastinal width, apical cap, widening of the right paratracheal stripe, or deviation of the nasogastric tube. Due to interobserver variation, there is good agreement between observers for the following four signs only: transverse mediastinal width, tracheal deviation, nasogastric tube deviation, nasogastric tube deviation, and right paratracheal stripe widening.

  20. Digital radiographic assessment of coronary flow reserve

    International Nuclear Information System (INIS)

    Vogel, R.A.

    1985-01-01

    A method for measuring relative changes in regional blood flow using digital radiographic enhancement of selective coronary arteriography. Coronary flow reserve is measured in individual arterial distributions using the washin ratio of contrast appearance time under baseline and hyperemic conditions. Information is quantitatively presented in functional (parametric) image format. These images, termed contrast medium appearance pictures (CMAP), depict the transit of contrast through the arterial, myocardial and early venous stages. This process can be divided into three general phases: data acquisition, CMAP formation and CMAP analysis. The technique has evolved over its development period from a cine film-based technology which required substantial processing time to a real-time digital radiographic technique

  1. RADIOGRAPHIC EXAMINATION OF TEMPOROMANDIBULAR DISORDERS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Heru Suryonegoro

    2015-06-01

    Full Text Available The temporomandibular joint has a very important role in the stomatognathic system. Its main function is for the opening and closing movement, mastication, and speech. It is located anterior to the ear. The temporomandibular joint connects maxilla and mandible through the articular fossa, hence the slightest change that happens would cause serious matters such as pain, exiting, speech disorder, difficulty in opening and closing movement, headache, and even trismus. In a child or an adolescent, the symptoms are often vague; everything is interpreted as “pain”. This is probably why temporomandibular disorder are often undetected by dentists. Therefore, patience and accuracy is needed to determine the actual disorder through means of clinical and radiographic examination. The radiographic examination suitable for child is the transcranial projection. This projection is believed to be more accurate amongst other projection for child patients.

  2. A Platform for X-Ray Thomson Scattering Measurements of Radiation Hydrodynamics Experiments on the NIF

    Science.gov (United States)

    Lefevre, Heath; Ma, Kevin; Belancourt, Patrick; MacDonald, Michael; Doeppner, Tilo; Keiter, Paul; Kuranz, Carolyn

    2017-10-01

    A recent experiment on the National Ignition Facility (NIF) radiographed the evolution of the Rayleigh-Taylor (RT) instability under high and low drive cases. This experiment showed that under a high drive the growth rate of the RT instability is reduced relative to the low drive case. The high drive launches a radiative shock, increases the temperature of the post-shock region, and ablates the spikes, which reduces the RT growth rate. The plasma parameters must be measured to validate this claim. We present a target design for making X-Ray Thomson Scattering (XRTS) measurements on radiation hydrodynamics experiments on NIF to measure the electron temperature of the shocked region in the above cases. Specifically, we show that a previously fielded NIF radiation hydrodynamics platform can be modified to allow sufficient signal and temperature resolution for XRTS measurements. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, Grant Number DE-NA0002956 and the National Science Foundation through the Basic Plasma Science and Engineering program.

  3. Modified newman and friedman extraoral radiographic technique.

    Science.gov (United States)

    Saberi, Eshagali; Hafezi, Ladan; Farhadmolashahi, Narges; Mokhtari, Manoochehr

    2012-01-01

    Good radiographs are required for endodontic therapy and because some patient's are intolerant to intraoral films and/or sensors, this can cause complications in endodontic treatment. Extraoral film placement can be used to obtain clinically diagnostic and working radiographs. The no. 2 receptor was placed against the model's cheek and centered in the molar-premolar area. The central beam was directed toward this area from the opposite side. The vertical and horizontal angles that achieved the most accurate radiograph were calculated by trial and error. The best method equated with the patient sitting upright and the Frankfort plane being horizontal to the floor and when the head was tilted 10 degrees toward the side being examined. For the upper posterior teeth the center of the image receptor was placed on the intersection of the ala-tragus and a parasagittal line while the upper border of receptor was parallel to the canthomeatal line; the cone was positioned a negative 25 degrees from the horizontal plane. The central beam was directed from midway between maxillary and mandibular premolars and molars of the opposite side. For the lower posterior teeth, the receptor was placed against the cheek on the side of interest and its lower border was parallel and 2 cm above the inferior border of the mandible. The cone was angled -20 degrees from the horizontal plane while the central beam was directed towards the mandibular molar-premolar region 1 cm below the lower border of the mandibular of the contralateral premolar/molar region. Using this novel technique, high quality images can be acquired for patients who cannot tolerate intraoral radiographs.

  4. Possibilities of radiographic digitalisation in dental clinics

    International Nuclear Information System (INIS)

    Zenobio, Madelon A.F.; Zenobio, Elton Goncalves

    2002-01-01

    In the evolution diagnostic processes by image, the improvement of the intrabucal radiographic sensibility generated and digitalized is today, of great expressiveness in the evolution and effectiveness in the odontological area. This methodology applicability as a possibility of a more precise and accurate diagnostic formulation among other advantages, justifies this technique use. This paper intends to, thorough the literature magazine and clinic case presentations to show its applicability in the daily odontological clinic, and specially, in the periodonty area. (author)

  5. Black Lung Benefits Act: standards for chest radiographs. Final rule.

    Science.gov (United States)

    2014-04-17

    Physicians and adjudicators use chest radiographs (X-rays) as a tool in evaluating whether a coal miner suffers from pneumoconiosis (black lung disease). Accordingly, the Department's regulations implementing the Black Lung Benefits Act allow the submission of radiographs in connection with benefit claims and set out quality standards for administering and interpreting film-based chest radiographs. This final rule updates the Department's existing film-radiograph standards and provides parallel standards for digital radiographs. This rule also updates outdated terminology and removes certain obsolete provisions.

  6. Artificial intelligence for analyzing orthopedic trauma radiographs.

    Science.gov (United States)

    Olczak, Jakub; Fahlberg, Niklas; Maki, Atsuto; Razavian, Ali Sharif; Jilert, Anthony; Stark, André; Sköldenberg, Olof; Gordon, Max

    2017-12-01

    Background and purpose - Recent advances in artificial intelligence (deep learning) have shown remarkable performance in classifying non-medical images, and the technology is believed to be the next technological revolution. So far it has never been applied in an orthopedic setting, and in this study we sought to determine the feasibility of using deep learning for skeletal radiographs. Methods - We extracted 256,000 wrist, hand, and ankle radiographs from Danderyd's Hospital and identified 4 classes: fracture, laterality, body part, and exam view. We then selected 5 openly available deep learning networks that were adapted for these images. The most accurate network was benchmarked against a gold standard for fractures. We furthermore compared the network's performance with 2 senior orthopedic surgeons who reviewed images at the same resolution as the network. Results - All networks exhibited an accuracy of at least 90% when identifying laterality, body part, and exam view. The final accuracy for fractures was estimated at 83% for the best performing network. The network performed similarly to senior orthopedic surgeons when presented with images at the same resolution as the network. The 2 reviewer Cohen's kappa under these conditions was 0.76. Interpretation - This study supports the use for orthopedic radiographs of artificial intelligence, which can perform at a human level. While current implementation lacks important features that surgeons require, e.g. risk of dislocation, classifications, measurements, and combining multiple exam views, these problems have technical solutions that are waiting to be implemented for orthopedics.

  7. Nosocomial Legionnaires’ Disease: Clinical and Radiographic Patterns

    Directory of Open Access Journals (Sweden)

    Thomas J Marrie

    1992-01-01

    Full Text Available From 1981 to 1991, 55 patients (33 males, 22 females, mean age 58.6 years with nosocomial Legionnaires’ disease were studied. The mortality rate was 64%. One-half of the patients developed nosocomial Legionnaires’ disease within three weeks of admission. A surprising clinical feature was the low rate of findings of consolidation on physical examination, despite the fact that 52% of patients had this finding on chest radiograph. More than one-half of patients had pre-existing lung disease, rendering a radiographic diagnosis of pneumonia due to Legionella pneumophila impossible in 16% of cases despite microbiological confirmation. Nineteen per cent of patients who had blood cultures done had a pathogen other than L pneumophila isolated, suggesting dual infection in at least some of the patients. When the clinical and radiographic findings were combined it was noted that 40% of patients had one of three patterns suggestive of nosocomial Legionnaires’ disease: rapidly progressive pneumonia, lobar opacity and multiple peripheral opacities. However, in 60% of patients there were no distinctive features.

  8. Radiographic examination of the stomach and duodenum

    International Nuclear Information System (INIS)

    De Lange, E.E.; Shaffer, H.A. Jr; Croft, B.Y.

    1990-01-01

    We compared retrospectively three groups of 150 patients who had undergone radiologic examinations of the stomach and duodenum. Each group was examined with a different barium suspension and radiographic technique: single-contrast (SC), double-contrast (DC), or biphasiccontrast (BC). The radiographs of each study were evaluated for technical quality and visualization of lesions. The number of X-ray exposures, films, and the amount of fluoroscopic time for each study were tabulated. The total radiation dose and cost for each technique were calculated. The BC examinations required the greatest number of radiographic exposures and X-ray films; however, cost was highest for the DC method. Fluoroscopy was significantly longer during the DC procedures, and the total radiation dose was also highest with this technique. Gaseous distention and barium coating of the stomach were equally good for the BC and DC groups, but X-ray penetration of the barium suspension during compression filming was significantly better in the BC and SC groups. Areae gastricae were most frequently seen during the BC studies and artifacts from excess secretions, barium flocculation or gas bubbles were least commonly present using this technique. Significantly more lesions were demonstrated in the stomach with the BC technique than with the other methods; however, the number of lesions found in the duodenum was the same for each technique. (author). 29 refs.; 6 tabs

  9. Opportunistic esophagitis in AIDS: radiographic diagnosis.

    Science.gov (United States)

    Levine, M S; Woldenberg, R; Herlinger, H; Laufer, I

    1987-12-01

    Thirty-five of 90 patients with acquired immunodeficiency syndrome (AIDS) seen between 1983 and 1986 underwent esophagography (double contrast in all but two) to rule out opportunistic esophagitis; 20 of the 35 were found to have fungal or viral esophagitis. A radiographic diagnosis of Candida esophagitis was made in 17 patients because of varying degrees of plaque formation. Seven of those patients had a grossly irregular or "shaggy" esophagus; in four, the diagnosis of AIDS was initially suspected from this finding. In the remaining three patients, a radiographic diagnosis of viral esophagitis (herpes simplex in two and cytomegalovirus in one) was made because of discrete ulcers on a normal background mucosa. Eighteen patients had endoscopic, clinical, or autopsy findings that corroborated the radiographic diagnosis; follow-up data were not available for two patients with Candida esophagitis. This experience suggests that fungal and viral esophagitis can often be differentiated with double-contrast esophagography, enabling appropriate antifungal or antiviral therapy to be instituted without endoscopic intervention.

  10. Radiographic analysis of extracorporeally irradiated autografts

    Energy Technology Data Exchange (ETDEWEB)

    Poffyn, Bart; Sys, Gwen; Uyttendaele, Dirk [Ghent University Hospital, Department of Orthopaedic Surgery, Ghent (Belgium); Maele, Georges van [Ghent University, Department of Public Health, Ghent (Belgium); Hoorebeke, Luc van [Ghent University, Department of Subatomic and Radiation Physics, Ghent (Belgium); Forsyth, Ramses [Ghent University Hospital, N. Goormaghtigh Institute of Pathology, Ghent (Belgium); Verstraete, Koenraad [Ghent University Hospital, Department of Radiology, Ghent (Belgium)

    2010-10-15

    To analyse the long-term radiographic findings of intercalary, pure osteoarticular, and composite bone grafts in patients with primary bone sarcoma who were treated by reimplantation of the bone as an orthotopic autograft. For this observational clinical study, 107 patients who presented with 108 malignant or locally aggressive benign bone tumours were treated by resection, extracorporeal irradiation (300 Gy), and reimplantation and fixation of the autograft. Bone healing features were evaluated with the International Society of Limb Salvage (ISOLS) graft evaluation method, which assesses fusion, resorption, fracture, graft shortening, fixation, subluxation, joint narrowing, and subchondral bone. A description of normal and abnormal healing patterns and complications comprised the secondary endpoint. Seventy-seven patients with complete radiographic data were selected for review. The mean ISOLS score was 78.2% (range 25.0-100%, median 79.2%). Three patient subgroups were created: intercalary graft, pure osteoarticular graft, and composite reconstruction consisting of an intercalary graft augmented with a prosthesis; the mean ISOLS scores were 81.3%, 70.7%, and 77.4%, respectively. Each item was scored individually, and no significant difference was observed (P = 0.225). This reconstruction technique is valid for the three methods described; bone stock is retained and, once the graft has healed, it behaves as normal bone. Close radiographic follow-up detects complications early, allowing timely interventions if necessary. (orig.)

  11. Standard reference radiographs for steel fusion welds

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This standard provides reference radiographs for steel fusion welds that contain typical discontinuities with varying severity levels in different thicknesses of material. The reference radiograph films are an adjunct to this standard and must be purchased separately from ASTM International if needed. 1.2 There are three volumes of reference radiographs based on seven nominal weld thicknesses as follows: Vol ISet of 16 plates (81/2 by 11 in.) covering base material up to and including ¼ in. (6.4 mm) in thickness. Vol IISet of 29 plates (8½ by 11 in.) covering base material over ¼ to and including 3 in. (6.4 to 76 mm) in thickness. Vol IIISet of 32 plates (8 ½ by 11 in.) covering base material over 3 to including 8 in. (76 to 203 mm) in thickness. 1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 This standard does not purport t...

  12. Design of Off-Axis PIAACMC Mirrors

    Science.gov (United States)

    Pluzhnik, Eugene; Guyon, Olivier; Belikov, Ruslan; Kern, Brian; Bendek, Eduardo

    2015-01-01

    The Phase-Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) provides an efficient way to control diffraction propagation effects caused by the central obstruction/segmented mirrors of the telescope. PIAACMC can be optimized in a way that takes into account both chromatic diffraction effects caused by the telescope obstructed aperture and tip/tilt sensitivity of the coronagraph. As a result, unlike classic PIAA, the PIAACMC mirror shapes are often slightly asymmetric even for an on-axis configuration and require more care in calculating off-axis shapes when an off-axis configuration is preferred. A method to design off-axis PIAA mirror shapes given an on-axis mirror design is presented. The algorithm is based on geometrical ray tracing and is able to calculate off-axis PIAA mirror shapes for an arbitrary geometry of the input and output beams. The method is demonstrated using the third generation PIAACMC design for WFIRST-AFTA (Wide Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets) telescope. Geometrical optics design issues related to the off-axis diffraction propagation effects are also discussed.

  13. Accuracy of radiographer reporting of paediatric brain CT

    International Nuclear Information System (INIS)

    Brandt, Andrew; Louw, Brand; Dekker, Gerrit; Andronikou, Savvas; Wieselthaler, Nicki; Kilborn, Tracy; Bertelsman, Jessica; Dreyer, Catherine

    2007-01-01

    Radiographer reporting has been studied for plain films and for ultrasonography, but not in paediatric brain CT in the emergency setting. To study the accuracy of radiographer reporting in paediatric brain CT. We prospectively collected 100 paediatric brain CT examinations. Films were read from hard copies using a prescribed tick sheet. Radiographers with 12 years' and 3 years' experience, respectively, were blinded to the history and were not trained in diagnostic film interpretation. The radiographers' results were compared with those of a consultant radiologist. Three categories were defined: abnormal scans, significant abnormalities and insignificant abnormalities. Both radiographers had an accuracy of 89.5% in reading a scan correctly as abnormal, and radiographer 1 had a sensitivity of 87.8% and radiographer 2 a sensitivity of 96%. Radiographer 1 had an accuracy in detecting a significant abnormality of 75% and radiographer 2 an accuracy of 48.6%, and the sensitivities for this category were 61.6% and 52.9%, respectively. Results for detecting the insignificant abnormalities were poorer. Selected radiographers could play an effective screening role, but lacking the sensitivity required for detecting significant abnormality, they could not be the final diagnostician. We recommend that the study be repeated after both radiographers have received formal training in interpretation of paediatric brain CT. (orig.)

  14. The forensic radiographer: a new member in the medicolegal team.

    Science.gov (United States)

    Schneider, Benjamin; Chevallier, Christine; Dominguez, Alejandro; Bruguier, Christine; Elandoy, Cristèle; Mangin, Patrice; Grabherr, Silke

    2012-03-01

    Multidetector computed tomography is becoming more widespread in forensic medicine. In most services, autopsy assistants perform the radiological examination. We introduced professional radiographers into the legal medicine service and hypothesized they would also be able to take over duties currently reserved for other specialists. The aims of this study were to evaluate if radiographers could be trained as "forensic radiographers" by (1) integrating graduated medical radiographers into the legal medicine service, (2) investigating the advantages of this collaboration, and (3) defining the duties of the forensic radiographers.The study was performed prospectively on a group of 8 recruited radiographers who underwent a testing period with special training. They learned the basics of medicolegal case treatment, the autonomous execution of postmortem computed tomography angiography, and postprocessing of data. Seven of 8 radiographers finished the training and were integrated into our service. Although all radiographers were able to fulfill the duties demanded after the training period, some radiographers could not enter or complete the program because they were unable to work with dead bodies.Our study presents the advantages of integrating radiographers into the medicolegal team and proposes how to train the forensic radiographers. In addition, the duties and responsibilities of these new specialists are defined.

  15. Relaxation to the state of molecular hydrodynamics in the generalized hydrodynamics of liquids

    Science.gov (United States)

    Markiv, B.; Omelyan, I.; Tokarchuk, M.

    2010-10-01

    The problem of relaxation of a nonequilibrium state to the state of molecular hydrodynamics is considered for a classical system of interacting particles using the Zubarev nonequilibrium statistical operator method. The wave-vector and frequency dependencies of the dynamical structure factor and momentum-momentum transverse correlation function are investigated on the basis of the appropriate generalized transport equations. Comparison with the results of molecular hydrodynamics and molecular-dynamics simulations is given and the characteristic time intervals of the studied relaxation processes are determined.

  16. Ex vivo and in vitro determination of the axial rotational axis of the human thoracic spine.

    Science.gov (United States)

    Molnár, Szabolcs; Manó, Sándor; Kiss, László; Csernátony, Zoltán

    2006-12-15

    Different geometrical and biomechanical evaluations were performed to determine the axial rotational axis of the thoracic spine. Our research group has been dealing with the determination of the axial rotational axis of the thoracic spine. Here, we would like to present the geometrical and experimental results of our trials. With our experiments, we are trying to evaluate the contradictions of the related literature. In the present state, we know quite a lot about the biomechanics of healthy and pathologic spines. Nevertheless, for a seemingly simple question like the position of the axial rotation of the thoracic spine, the literature gives contradicting results. During correction of a scoliotic deformity, when trying to correct the pathologic rotation, not knowing the physiologic rotation can be hazardous. We wanted to clarify this question, so we examined the thoracic spine in many different ways. First, we examined the problem from a geometrical point of view then we modeled the different rotational axes by studying the change in volume of the spinal canal. Finally, we used cadaver spines that we rotated and examined with radiographs and digital pictures. Based on the results, we made the following establishments: most of the center points fell on the anterior half of the vertebral body or into the spinal canal, basically on the midsagittal axis of the vertebra. The rib cage has a significant effect on the place of the axis. After removing the ribs, the axis of axial rotation moved forward. After evaluating the results, we determined that the most likely place for the rotational axis is on the median-sagittal plane, in the anterior portion of the spinal canal.

  17. Preoperative Radiographic Parameters to Predict a Higher Pseudarthrosis Rate After Anterior Cervical Discectomy and Fusion.

    Science.gov (United States)

    Choi, Sung H; Cho, Jae H; Hwang, Chang J; Lee, Choon S; Gwak, Hyun W; Lee, Dong-Ho

    2017-12-01

    Retrospective study. To determine whether postoperative pseudarthrosis can be predicted from specific preoperative radiograph measurements. Various factors reportedly influence the occurrence of pseudarthrosis after anterior cervical discectomy and fusion (ACDF). However, to our knowledge, there are no reports on the relationships between preoperative radiographic parameters and pseudarthrosis. We analyzed 84 consecutive patients (45 males, 39 females, mean age, 58.9 ± 11.2 yrs) who underwent ACDF. In all patients, allografts filled with local chip bone were inserted after discectomy and anterior plating was performed. On preoperative plain radiographs, we analyzed C2-C7 sagittal vertical axis, T1 sagittal slope, segmental motion, global cervical motion, and location of fusion segments. Pseudarthrosis was diagnosed as interspinous motion >1 mm with superjacent interspinous motion ≥4 mm on magnified dynamic lateral radiographs. Multivariate logistic regression was used to analyze the risk factors for pseudarthrosis and the receiver operating characteristic (ROC) curve was used to define a cutoff value. One hundred and twenty-five segments from 84 patients were included. The pseudarthrosis rate was 29% based on number of patients (24/84) and 20% based on number of segments (25/125). Multilevel surgery and segments at the lowest levels showed higher pseudarthrosis rates (P = 0.01). Per multivariate logistic regression analysis, greater preoperative segmental motion, greater preoperative T1 sagittal slope, and C6-7 segments were associated with a higher risk of pseudarthrosis (all P preoperative segmental motion, greater preoperative T1 sagittal slope, and lower fusion levels could be risk factors for pseudarthrosis following ACDF. Preoperative segmental motion >12° is likely to be an important indicator of the development of pseudarthrosis. 3.

  18. Hydrodynamic Liner Experiments Using the Ranchero Flux Compression Generator System

    Science.gov (United States)

    Goforth, J. H.; Atchison, W. L.; Fowler, C. M.; Herrera, D. H.; King, J. C.; Lopez, E. A.; Oona, H.; Reinovsky, R. E.; Stokes, J. L.; Tabaka, L. J.; Tasker, D. G.; Torres, D. T.; Sena, F. C.; McGuire, J. A.; Lindemuth, I. R.; Faehl, R. J.; Keinigs, R. K.; Garcia, O. F.; Broste, B.

    2004-11-01

    At Los Alamos, we investigate solid density materials under extreme conditions of high pressure or strain. To further these studies, we develop pulsed power techniques for driving high energy imploding liners. We have developed the Ranchero explosive-driven magnetic flux compression generator (FCG) system to perform such experiments at very high energy, in remote locations. Our first charter is to support the development of the Atlas capacitor bank [1] which, when completed in 2001, will deliver up to 30 MA to hydrodynamic liners. The basic unit of the Ranchero system is a 1.4 m long coaxial FCG that is simultaneously initiated along its axis and has an armature expansion ratio of 2:1. We performed initial system tests using 43 cm long [2,3] coaxial modules and are finalizing the design and development of our 1.4 m detonation system. This development, which met with unexpected difficulties, is the subject of another paper in this conference [4]. The 43cm module combined with the 2.4 MJ capacitor bank at our high explosive pulsed power facility has the capability of delivering ~40 MA to a load of ~5 nH. Coupled with a fuse opening switch (FOS), the system will generate a good approximation of Atlas waveforms with 5 nH in the load and transmission lines. This allows us to begin preliminary Atlas related tests before the 1.4 m module is completed. Herein is described our efforts to develop the capability and the design of our first imploding liner experiment.

  19. An updated Lagrangian particle hydrodynamics (ULPH) for Newtonian fluids

    Science.gov (United States)

    Tu, Qingsong; Li, Shaofan

    2017-11-01

    In this work, we have developed an updated Lagrangian particle hydrodynamics (ULPH) for Newtonian fluid. Unlike the smoothed particle hydrodynamics, the non-local particle hydrodynamics formulation proposed here is consistent and convergence. Unlike the state-based peridynamics, the discrete particle dynamics proposed here has no internal material bond between particles, and it is not formulated with respect to initial or a fixed referential configuration. In specific, we have shown that (1) the non-local update Lagrangian particle hydrodynamics formulation converges to the conventional local fluid mechanics formulation; (2) the non-local updated Lagrangian particle hydrodynamics can capture arbitrary flow discontinuities without any changes in the formulation, and (3) the proposed non-local particle hydrodynamics is computationally efficient and robust.

  20. Hydrodynamic evolution of neutron star merger remnants

    Science.gov (United States)

    Liu, Men-Quan; Zhang, Jie

    2017-11-01

    Based on the special relativistic hydrodynamic equations and updated cooling function, we investigate the long-term evolution of neutron stars merger (NSM) remnants by a one-dimensional hydrodynamic code. Three NSM models from one soft equation of state, SFHo, and two stiff equations of state, DD2 and TM1, are used to compare their influences on the hydrodynamic evolution of remnants. We present the luminosity, mass and radius of remnants, as well as the velocity, temperature and density of shocks. For a typical interstellar medium (ISM) density with solar metallicity, we find that the NSM remnant from the SFHo model makes much more changes to ISM in terms of velocity, density and temperature distributions, compared with the case of DD2 and TM1 models. The maximal luminosity of the NSM remnant from the SFHo model is 3.4 × 1038 erg s-1, which is several times larger than that from DD2 and TM1 models. The NSM remnant from the SFHo model can maintain high luminosity (>1038 erg s-1) for 2.29 × 104 yr. Furthermore, the density and temperature of remnants at the maximal luminosity are not sensitive to the power of the original remnant. For the ISM with the solar metallicity and nH = 1 cm- 3, the density of the first shock ∼10-23 g cm-3 and the temperature ∼3 × 105 K in the maximal luminosity phase; The temperature of the first shock decreases and there is a thin 'dense' shell with density ∼10-21 g cm-3 after the maximal luminosity. These characteristics may be helpful for future observations of NSM remnants.

  1. An overview of hydrodynamic studies of mineralization

    Directory of Open Access Journals (Sweden)

    Guoxiang Chi

    2011-07-01

    Full Text Available Fluid flow is an integral part of hydrothermal mineralization, and its analysis and characterization constitute an important part of a mineralization model. The hydrodynamic study of mineralization deals with analyzing the driving forces, fluid pressure regimes, fluid flow rate and direction, and their relationships with localization of mineralization. This paper reviews the principles and methods of hydrodynamic studies of mineralization, and discusses their significance and limitations for ore deposit studies and mineral exploration. The driving forces of fluid flow may be related to fluid overpressure, topographic relief, tectonic deformation, and fluid density change due to heating or salinity variation, depending on specific geologic environments and mineralization processes. The study methods may be classified into three types, megascopic (field observations, microscopic analyses, and numerical modeling. Megascopic features indicative of significantly overpressured (especially lithostatic or supralithostatic fluid systems include horizontal veins, sand injection dikes, and hydraulic breccias. Microscopic studies, especially microthermometry of fluid inclusions and combined stress analysis and microthermometry of fluid inclusion planes (FIPs can provide important information about fluid temperature, pressure, and fluid-structural relationships, thus constraining fluid flow models. Numerical modeling can be carried out to solve partial differential equations governing fluid flow, heat transfer, rock deformation and chemical reactions, in order to simulate the distribution of fluid pressure, temperature, fluid flow rate and direction, and mineral precipitation or dissolution in 2D or 3D space and through time. The results of hydrodynamic studies of mineralization can enhance our understanding of the formation processes of hydrothermal deposits, and can be used directly or indirectly in mineral exploration.

  2. A high speed vertical axis wind machine

    National Research Council Canada - National Science Library

    South, P

    1976-01-01

    The operational feasibility of vertical axis wind machines was investigated at the National Aeronautical Establishment in Ottawa through use of a wind tunnel and a rotor with blades curved in a skipping rope shape...

  3. Computer simulation of the fire-tube boiler hydrodynamics

    Directory of Open Access Journals (Sweden)

    Khaustov Sergei A.

    2015-01-01

    Full Text Available Finite element method was used for simulating the hydrodynamics of fire-tube boiler with the ANSYS Fluent 12.1.4 engineering simulation software. Hydrodynamic structure and volumetric temperature distribution were calculated. The results are presented in graphical form. Complete geometric model of the fire-tube boiler based on boiler drawings was considered. Obtained results are suitable for qualitative analysis of hydrodynamics and singularities identification in fire-tube boiler water shell.

  4. Moving least-squares corrections for smoothed particle hydrodynamics

    OpenAIRE

    Bilotta, G.; Russo, G.; Herault, A.; Del Negro, C.

    2011-01-01

    First-order moving least-squares are typically used in conjunction with smoothed particle hydrodynamics in the form of post-processing filters for density fields, to smooth out noise that develops in most applications of smoothed particle hydrodynamics. We show how an approach based on higher-order moving least-squares can be used to correct some of the main limitations in gradient and second-order derivative computation in classic smoothed particle hydrodynamics formulations. With a small in...

  5. Characterization of the hydrodynamics in a miniaturized dissolution apparatus

    DEFF Research Database (Denmark)

    Johansson, Kristoffer E; Plum, Jakob; Mosleh, Majid

    2018-01-01

    The hydrodynamics of a miniaturized dissolution apparatus was characterized using computational fluid dynamics (CFD) simulations and analyzed in relation to the biorelevance and robustness of measurements of drug dissolution and precipitation kinetics from supersaturated drug solutions. The effect...... geometry influences the hydrodynamics of the system and indicates that an off-center probe position may result in more robust measurements. Furthermore, the study shows that the agitator geometry has a significant effect on supersaturation studies due to differences in the hydrodynamic shear produced...

  6. Fast lattice Boltzmann solver for relativistic hydrodynamics.

    Science.gov (United States)

    Mendoza, M; Boghosian, B M; Herrmann, H J; Succi, S

    2010-07-02

    A lattice Boltzmann formulation for relativistic fluids is presented and numerically validated through quantitative comparison with recent hydrodynamic simulations of relativistic fluids. In order to illustrate its capability to handle complex geometries, the scheme is also applied to the case of a three-dimensional relativistic shock wave, generated by a supernova explosion, impacting on a massive interstellar cloud. This formulation opens up the possibility of exporting the proven advantages of lattice Boltzmann methods, namely, computational efficiency and easy handling of complex geometries, to the context of (mildly) relativistic fluid dynamics at large, from quark-gluon plasmas up to supernovae with relativistic outflows.

  7. The frontal method in hydrodynamics simulations

    Science.gov (United States)

    Walters, R.A.

    1980-01-01

    The frontal solution method has proven to be an effective means of solving the matrix equations resulting from the application of the finite element method to a variety of problems. In this study, several versions of the frontal method were compared in efficiency for several hydrodynamics problems. Three basic modifications were shown to be of value: 1. Elimination of equations with boundary conditions beforehand, 2. Modification of the pivoting procedures to allow dynamic management of the equation size, and 3. Storage of the eliminated equations in a vector. These modifications are sufficiently general to be applied to other classes of problems. ?? 1980.

  8. Hydrodynamics in a swarm of rising bubbles

    International Nuclear Information System (INIS)

    Riboux, G.

    2007-04-01

    In many applications, bubbles are used to agitate a liquid in order to enhance mixing and transfer. This work is devoted to the study of the hydrodynamics in a stable bubble column. Experimentally, we have determined the properties of the velocity fluctuations inside and behind a homogeneous swarm of rising bubbles for different bubble sizes and gas volume fractions α: self-similarity in α 0,4 , spectrum in k -3 and integral length scale controlled by buoyancy. Numerically, we have reproduced these properties by means of large-scale simulations, the bubbles being modeled by volume-forces. This confirms that the dynamics is controlled by wake interactions. (author)

  9. Hydrodynamic instabilities in an ablation front

    Energy Technology Data Exchange (ETDEWEB)

    Piriz, A R; Portugues, R F [E.T.S.I. Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)

    2004-06-01

    The hydrodynamic stability of an ablation front is studied for situations in which the wavelength of the perturbations is larger than the distance to the critical surface where the driving radiation is absorbed. An analytical model is presented, and it shows that under conditions in which the thermal flux is limited within the supercritical region of the ablative corona, the front may behave like a flame or like an ablation front, depending on the perturbation wavelength. For relatively long wavelengths the critical and ablation surfaces practically lump together into a unique surface and the front behaves like a flame, whereas for the shortest wavelengths the ablation front substructure is resolved.

  10. GASOLINE: Smoothed Particle Hydrodynamics (SPH) code

    Science.gov (United States)

    N-Body Shop

    2017-10-01

    Gasoline solves the equations of gravity and hydrodynamics in astrophysical problems, including simulations of planets, stars, and galaxies. It uses an SPH method that features correct mixing behavior in multiphase fluids and minimal artificial viscosity. This method is identical to the SPH method used in the ChaNGa code (ascl:1105.005), allowing users to extend results to problems requiring >100,000 cores. Gasoline uses a fast, memory-efficient O(N log N) KD-Tree to solve Poisson's Equation for gravity and avoids artificial viscosity in non-shocking compressive flows.

  11. Postexplosion hydrodynamics of supernovae in red supergiants

    Science.gov (United States)

    Herant, Marc; Woosley, S. E.

    1994-01-01

    Shock propagation, mixing, and clumping are studied in the explosion of red supergiants as Type II supernovae using a two-dimensional smooth particle hydrodynamic (SPH) code. We show that extensive Rayleigh-Talor instabilities develop in the ejecta in the wake of the reverse shock wave. In all cases, the shell structure of the progenitor is obliterated to leave a clumpy, well-mixed supernova remnant. However, the occurrence of mass loss during the lifetime of the progenitor can significantly reduce the amount of mixing. These results are independent of the Type II supernova explosion mechanism.

  12. Hydrodynamic approach to p–Pb

    Energy Technology Data Exchange (ETDEWEB)

    Bożek, Piotr, E-mail: piotr.bozek@ifj.edu.pl [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, PL-30059 Kraków (Poland); Institute of Nuclear Physics PAN, PL-31342 Kraków (Poland); Broniowski, Wojciech, E-mail: wojciech.broniowski@ifj.edu.pl [Institute of Nuclear Physics PAN, PL-31342 Kraków (Poland); Institute of Physics, Jan Kochanowski University, PL-25406 Kielce (Poland)

    2014-06-15

    The formation and collective expansion of the fireball formed in ultrarelativistic p–A and d–A collisions is discussed. Predictions of the hydrodynamic model are compared to recent experimental results. The presence of strong final state interaction effects in the small dense systems is consistent with the observed azimuthal anisotropy of the flow and with the mass dependence of the average transverse momentum and of the elliptic flow. This raises the question of the mechanism explaining such a rapid build-up of the collective flow and the large degree of local equilibration needed to justify this scenario.

  13. UMAPRM: Uniformly sampling the medial axis

    KAUST Repository

    Yeh, Hsin-Yi Cindy

    2014-05-01

    © 2014 IEEE. Maintaining clearance, or distance from obstacles, is a vital component of successful motion planning algorithms. Maintaining high clearance often creates safer paths for robots. Contemporary sampling-based planning algorithms That utilize The medial axis, or The set of all points equidistant To Two or more obstacles, produce higher clearance paths. However, They are biased heavily Toward certain portions of The medial axis, sometimes ignoring parts critical To planning, e.g., specific Types of narrow passages. We introduce Uniform Medial Axis Probabilistic RoadMap (UMAPRM), a novel planning variant That generates samples uniformly on The medial axis of The free portion of Cspace. We Theoretically analyze The distribution generated by UMAPRM and show its uniformity. Our results show That UMAPRM\\'s distribution of samples along The medial axis is not only uniform but also preferable To other medial axis samplers in certain planning problems. We demonstrate That UMAPRM has negligible computational overhead over other sampling Techniques and can solve problems The others could not, e.g., a bug Trap. Finally, we demonstrate UMAPRM successfully generates higher clearance paths in The examples.

  14. A hydrodynamically suspended, magnetically sealed mechanically noncontact axial flow blood pump: design of a hydrodynamic bearing.

    Science.gov (United States)

    Mitamura, Yoshinori; Kido, Kazuyuki; Yano, Tetsuya; Sakota, Daisuke; Yambe, Tomoyuki; Sekine, Kazumitsu; OKamoto, Eiji

    2007-03-01

    To overcome the drive shaft seal and bearing problem in rotary blood pumps, a hydrodynamic bearing, a magnetic fluid seal, and a brushless direct current (DC) motor were employed in an axial flow pump. This enabled contact-free rotation of the impeller without material wear. The axial flow pump consisted of a brushless DC motor, an impeller, and a guide vane. The motor rotor was directly connected to the impeller by a motor shaft. A hydrodynamic bearing was installed on the motor shaft. The motor and the hydrodynamic bearing were housed in a cylindrical casing and were waterproofed by a magnetic fluid seal, a mechanically noncontact seal. Impeller shaft displacement was measured using a laser sensor. Axial and radial displacements of the shaft were only a few micrometers for motor speed up to 8500 rpm. The shaft did not make contact with the bearing housing. A flow of 5 L/min was obtained at 8000 rpm at a pressure difference of 100 mm Hg. In conclusion, the axial flow blood pump consisting of a hydrodynamic bearing, a magnetic fluid seal, and a brushless DC motor provided contact-free rotation of the impeller without material wear.

  15. Study on numerical calculation method for hydrodynamic parameters of WEC

    Directory of Open Access Journals (Sweden)

    Lijiao Shen

    2017-01-01

    Full Text Available For the effect of hydrodynamic parameters on the dynamic performance of wave energy devices is very significant, these parameters must be considered carefully when adjusting dynamic characteristics of devices. On the other hand calculating hydrodynamic parameter of devices accurately can guarantee rational dynamic property parameter adjustment. By using CFD technique and considering the definition of hydrodynamic parameters, the phase relationship between added mass and damp as well as the equation of forces, one new calculation method of hydrodynamic parameter was presented. Finally one example demonstrated the effectiveness of the new analysis method presented in this paper.

  16. Hydrodynamization and transient modes of expanding plasma in kinetic theory

    CERN Document Server

    Heller, Michal P.; Spalinski, Michal

    2016-01-01

    We study the transition to hydrodynamics in a weakly-coupled model of quark-gluon plasma given by kinetic theory in the relaxation time approximation. Our studies uncover qualitative similarities to the results on hydrodynamization in strongly coupled gauge theories. In particular, we demonstrate that the gradient expansion in this model has vanishing radius of convergence. The asymptotic character of the hydrodynamic gradient expansion is crucial for the recently discovered applicability of hydrodynamics at large gradients. Furthermore, the analysis of the resurgent properties of the series provides, quite remarkably, indication for the existence of a novel transient, damped oscillatory mode of expanding plasmas in kinetic theory.

  17. Technical errors in intraoral radiographs performed by undergraduate students

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Laureano da Rosa

    Full Text Available Objectives: To evaluate the technical errors in periapical examinations performed by dental students. Methods: Patient record charts at the dental clinic of the dentistry course were analyzed. Of these, the charts that presented at least ten periapical intraoral radiographs were used in the study, therefore a total of 219 patient record charts were selected, totaling 2 821 radiographs. The radiographs were analyzed one by one, using an uniform light negatoscope, in a darkened room, by a professional radiologist, taking into consideration the following evaluation criteria: technically good and unsatisfactory radiographs. The technical errorswere classified as errors in radiographic technique and radiographic processing errors. The data on quality critera stipulated and obtainedin the evaluation were tabulated, intervals of confidence were used to infer the percentage that were suitable and unsuitable in the studied period, and were statistically analyzed using the chi-square test, at the level of significance of 5%. Results: The results were: of the 2 821 radiographs analyzed, only 1 425 (50.51% were technically good. of the 1 396 (49.49% considered inadequat, 1 155 (82.74% presented errors in radiographic technique, while 241 (17.26% presented radiographic processing errors. The most frequently repeated error was image overlapping (32.88%, followed by the underexposure (25.43%, cut of the tooth (9.31%, chemicalcontamination problems (4.51%, cone cut (3.15%, other errors in radiographic technique (1.86% and other radiographic processing errors (1.43%. Conclusion: The conclusion was that steps must be taken to improve the quality of radiographs obtained because, although they did not make it impossible to interpret the radiographs, this was made extremely difficult, and the depreciated the value of the achives of past clinical situations and cases.

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

    Science.gov (United States)

    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.

  19. Mesiodens: a radiographic study in children.

    Science.gov (United States)

    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.

  20. Artificial intelligence for analyzing orthopedic trauma radiographs

    Science.gov (United States)

    Olczak, Jakub; Fahlberg, Niklas; Maki, Atsuto; Razavian, Ali Sharif; Jilert, Anthony; Stark, André; Sköldenberg, Olof

    2017-01-01

    Background and purpose — Recent advances in artificial intelligence (deep learning) have shown remarkable performance in classifying non-medical images, and the technology is believed to be the next technological revolution. So far it has never been applied in an orthopedic setting, and in this study we sought to determine the feasibility of using deep learning for skeletal radiographs. Methods — We extracted 256,000 wrist, hand, and ankle radiographs from Danderyd’s Hospital and identified 4 classes: fracture, laterality, body part, and exam view. We then selected 5 openly available deep learning networks that were adapted for these images. The most accurate network was benchmarked against a gold standard for fractures. We furthermore compared the network’s performance with 2 senior orthopedic surgeons who reviewed images at the same resolution as the network. Results — All networks exhibited an accuracy of at least 90% when identifying laterality, body part, and exam view. The final accuracy for fractures was estimated at 83% for the best performing network. The network performed similarly to senior orthopedic surgeons when presented with images at the same resolution as the network. The 2 reviewer Cohen’s kappa under these conditions was 0.76. Interpretation — This study supports the use for orthopedic radiographs of artificial intelligence, which can perform at a human level. While current implementation lacks important features that surgeons require, e.g. risk of dislocation, classifications, measurements, and combining multiple exam views, these problems have technical solutions that are waiting to be implemented for orthopedics. PMID:28681679

  1. On being dyslexic: Student radiographers' perspectives

    International Nuclear Information System (INIS)

    Murphy, Fred

    2011-01-01

    The purpose of this paper was to provide an insight into life as a dyslexic student radiographer, identify barriers and risks in clinical training, and develop recommendations for the support of students with dyslexia. The paucity of research into dyslexia within the radiography profession is worrying, with attention focused only on the support provided by Higher Education Institutions (HEI) or inferences drawn from the experiences of other healthcare students. The impact and significance of dyslexia for student radiographers in clinical practice has never been investigated. Results: On a self-reporting scale of clinical tasks there was little or no difference between dyslexic students and non-dyslexics. Some minor traits commonly associated with dyslexics were also reported by students with no learning disabilities and an inclusion support plan for all students was advocated. In-depth interviews of 10 student radiographers revealed six distinct themes of visualising the disability, self-protection, strengths and talents, time, the badge of disability and adjustments and support. Like other healthcare students, some radiography students reported significant difficulties and prejudices and very little structured support in the clinical environment. Despite the Special Educational Needs and Disability Act being in place for several years, the support in clinical departments fell significantly short of that provided in the universities. The dyslexic students took extra responsibility for their own learning and some had developed complex coping strategies to overcome any difficulties. Conclusion: Several inclusive recommendations were developed as a result of this study that could be used to support all students on clinical placement.

  2. Clinical and radiographic degenerative spondylolisthesis (CARDS) classification.

    Science.gov (United States)

    Kepler, Christopher K; Hilibrand, Alan S; Sayadipour, Amir; Koerner, John D; Rihn, Jeffrey A; Radcliff, Kristen E; Vaccaro, Alexander R; Albert, Todd J; Anderson, D Greg

    2015-08-01

    Lumbar degenerative spondylolisthesis (DS) is a common, acquired condition leading to disabling back and/or leg pain. Although surgery is common used to treat patients with severe symptoms, there are no universally accepted treatment guidelines. Wide variation in vertebral translation, disc collapse, sagittal alignment, and vertebral mobility suggests this is a heterogeneous disease. A classification scheme would be useful to differentiate homogenous subgroups that may benefit from different treatment strategies. To develop and test the reliability of a simple, clinically useful classification scheme for lumbar DS. Retrospective case series. One hundred twenty-six patients. Proposed radiographic classification system. A classification system is proposed that considers disc space height, sagittal alignment and translation, and the absence or presence of unilateral or bilateral leg pain. Test cases were graded by six observers to establish interobserver reliability and regraded in a different order 1 month later to establish intraobserver reliability using Kappa analysis. To establish the relative prevalence of each subtype, a series of 100 consecutive patients presenting with L4-L5 DS were classified. Four radiographic subtypes were identified: Type A: advanced Disc space collapse without kyphosis; Type B: disc partially preserved with translation of 5 mm or less; Type C: disc partially preserved with translation of more than 5 mm; and Type D: kyphotic alignment. The leg pain modifier 0 denotes no leg pain, 1 denotes unilateral leg pain, and 2 represents bilateral leg pain. The Kappa value describing interobserver reliability was 0.82, representing near-perfect agreement. Intraobserver reliability analysis demonstrated Kappa=0.83, representing near-perfect agreement. Grading of the consecutive series of 100 patients revealed the following distribution: 16% Type A, 37% Type B, 33% Type C, and 14% Type D. A new radiographic and clinical classification scheme for

  3. Radiographic analysis of temporomandibular joint arthrosis

    Energy Technology Data Exchange (ETDEWEB)

    You, Dong Soo [Department of Oral Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1984-11-15

    The author analysed the bone changes, the positional relationships between condylar head and articular fossa, and the interrelationship between the bone changes and the abnormal position of condylar head, from 1,036 radiographs of 259 patients with temporomandibular joint arthrosis, which were obtained by the oblique-lateral transcranial projection and orthopantomograms. The results were as follows: 1. Among the radiographic bone changes of the temporomandibular joint arthrosis, deformity was 36..90% (217 cases), sclerosis 34.18% (201 cases), erosive change 25.58% (152 cases) and marginal proliferation 3.06% (18 cases) respectively. 2. In the positional changes between condylar head and articular fossa, the downward positioning of condylar head in centric occlusion was most frequent (36.90%), of which frequency was significantly higher than forward positioning (11.22%) and backward positioning (4.76%) in same condition. Also, radiographs showed that the enlargement of articular space showed higher frequency than its narrowing. In the opening position of mouth, the restrict ed movement of condylar head within articular fossa was most frequent (35.03%). The forward positioning and the downward positioning was 15.65% and 9.52% respectively. Also, radiographs revealed that the incomplete movement or no positional change of condylar head was most frequent. 3. In the interrelationship between bone changes and abnormal position of condylar head, deformity was 42.79% in the cases of downward positioning of condylar head in centric occlusion and 37.50% in those of normal positioning of condylar head in same condition. This revealed that deformity was most frequent bone change in above condylar positionings. However, erosive change was 34.62% in the cases of downward positioning of condylar head in centric occlusion and 33 .33% in those of forward positioning. In opening position of condylar head, and deformity in the cases of norma l positioning, forward positioning and

  4. Radiographic analysis of temporomandibular joint arthrosis

    International Nuclear Information System (INIS)

    You, Dong Soo

    1984-01-01

    The author analysed the bone changes, the positional relationships between condylar head and articular fossa, and the interrelationship between the bone changes and the abnormal position of condylar head, from 1,036 radiographs of 259 patients with temporomandibular joint arthrosis, which were obtained by the oblique-lateral transcranial projection and orthopantomograms. The results were as follows: 1. Among the radiographic bone changes of the temporomandibular joint arthrosis, deformity was 36..90% (217 cases), sclerosis 34.18% (201 cases), erosive change 25.58% (152 cases) and marginal proliferation 3.06% (18 cases) respectively. 2. In the positional changes between condylar head and articular fossa, the downward positioning of condylar head in centric occlusion was most frequent (36.90%), of which frequency was significantly higher than forward positioning (11.22%) and backward positioning (4.76%) in same condition. Also, radiographs showed that the enlargement of articular space showed higher frequency than its narrowing. In the opening position of mouth, the restrict ed movement of condylar head within articular fossa was most frequent (35.03%). The forward positioning and the downward positioning was 15.65% and 9.52% respectively. Also, radiographs revealed that the incomplete movement or no positional change of condylar head was most frequent. 3. In the interrelationship between bone changes and abnormal position of condylar head, deformity was 42.79% in the cases of downward positioning of condylar head in centric occlusion and 37.50% in those of normal positioning of condylar head in same condition. This revealed that deformity was most frequent bone change in above condylar positionings. However, erosive change was 34.62% in the cases of downward positioning of condylar head in centric occlusion and 33 .33% in those of forward positioning. In opening position of condylar head, and deformity in the cases of norma l positioning, forward positioning and

  5. Chest radiographic manifestations of scrub typhus

    Directory of Open Access Journals (Sweden)

    KPP Abhilash

    2016-01-01

    Full Text Available Background and Rationale: Respiratory system involvement in scrub typhus is seen in 20–72% of patients. In endemic areas, good understanding and familiarity with the various radiologic findings of scrub typhus are essential in identifying pulmonary complications. Materials and Methods: Patients admitted to a tertiary care center with scrub typhus between October 2012 and September 2013 and had a chest X ray done were included in the analysis. Details and radiographic findings were noted and factors associated with abnormal X-rays were analyzed. Results: The study cohort contained 398 patients. Common presenting complaints included fever (100%, generalized myalgia (83%, headache (65%, dyspnea (54%, cough (24.3%, and altered sensorium (14%. Almost half of the patients (49.4% had normal chest radiographs. Common radiological pulmonary abnormalities included pleural effusion (14.6%, acute respiratory distress syndrome (14%, airspace opacity (10.5%, reticulonodular opacities (10.3%, peribronchial thickening (5.8%, and pulmonary edema (2%. Cardiomegaly was noted in 3.5% of patients. Breathlessness, presence of an eschar, platelet counts of 2 mg/dL had the highest odds of having an abnormal chest radiograph. Patients with an abnormal chest X-ray had a higher requirement of noninvasive ventilation (odds ratio [OR]: 13.98; 95% confidence interval CI: 5.89–33.16, invasive ventilation (OR: 18.07; 95% CI: 6.42–50.88, inotropes (OR: 8.76; 95% CI: 4.35–17.62, higher involvement of other organ systems, longer duration of hospital stay (3.18 ± 3 vs. 7.27 ± 5.58 days; P< 0.001, and higher mortality (OR: 4.63; 95% CI: 1.54–13.85. Conclusion: Almost half of the patients with scrub typhus have abnormal chest radiographs. Chest radiography should be included as part of basic evaluation at presentation in patients with scrub typhus, especially in those with breathlessness, eschar, jaundice, and severe thrombocytopenia.

  6. Electrophoretic recording of electronically stored radiographs.

    Science.gov (United States)

    Hinz, H D; Lobl, H

    1985-01-01

    Continuous tone hard copies of electronically stored radiographs are recorded on transparent film with a silverless conductive coating by electrophoretic deposition of toner particles. A stationary experimental print head with a row of 320 electrodes (eight electrodes per mm) was employed. The performance of the recording process with regard to the most important parameters, i.e., toner concentration, width of the gap between recording medium and electrodes, recording voltage, and speed will be described. The process exhibits continuous tone characteristics, because the optical density can be varied continuously by the recording voltage. The image resolution which can be achieved is characterized by a modulation transfer function.

  7. Normal radiographic findings. 4. act. ed.; Roentgennormalbefunde

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, T.B. [Gemeinschaftspraxis fuer Radiologie und Nuklearmedizin, Dillingen (Germany)

    2003-07-01

    This book can serve the reader in three ways: First, it presents normal findings for all radiographic techniques including KM. Important data which are criteria of normal findings are indicated directly in the pictures and are also explained in full text and in summary form. Secondly, it teaches the systematics of interpreting a picture - how to look at it, what structures to regard in what order, and for what to look in particular. Checklists are presented in each case. Thirdly, findings are formulated in accordance with the image analysis procedure. All criteria of normal findings are defined in these formulations, which make them an important didactic element. (orig.)

  8. Normal radiographic findings. 4. act. ed.

    International Nuclear Information System (INIS)

    Moeller, T.B.

    2003-01-01

    This book can serve the reader in three ways: First, it presents normal findings for all radiographic techniques including KM. Important data which are criteria of normal findings are indicated directly in the pictures and are also explained in full text and in summary form. Secondly, it teaches the systematics of interpreting a picture - how to look at it, what structures to regard in what order, and for what to look in particular. Checklists are presented in each case. Thirdly, findings are formulated in accordance with the image analysis procedure. All criteria of normal findings are defined in these formulations, which make them an important didactic element. (orig.)

  9. Radiographic investigations during medico-legal autopsies

    International Nuclear Information System (INIS)

    Bratzke, H.; Schneider, V.; Dietz, W.

    1982-01-01

    During the last 13 years (1968-1980), 427 radiographic examinations were carried out during the course of medico-legal autopsies at the Institute of Forensic Medicine at the Free University of Berlin. Important problems were the demonstration of retained foreign bodies resulting from shooting, stabbing or blunt trauma, bone injuries, identification, and the question of life in neonates. An historical survey is given and 12 cases with special forensic problems are illustrated and discussed, and further means of investigations are described. (orig.) [de

  10. General-purpose radiographic and fluoroscopic table

    International Nuclear Information System (INIS)

    Ishizaki, Noritaka

    1982-01-01

    A new series of diagnostic tables, Model DT-KEL, was developed for general-purpose radiographic and fluoroscopic systems. Through several investigations, the table was so constructed that the basic techniques be general radiography and GI examination, and other techniques be optionally added. The diagnostic tables involve the full series of the type for various purposes and are systematized with the surrounding equipment. A retractable mechanism of grids was adopted first for general use. The fine grids with a density of 57 lines per cm, which was adopted in KEL-2, reduced the X-ray doses by 16 percent. (author)

  11. Revolutionizing radiographic diagnostic accuracy in periodontics

    Directory of Open Access Journals (Sweden)

    Brijesh Sharma

    2016-01-01

    Full Text Available Effective diagnostic accuracy has in some way been the missing link between periodontal diagnosis and treatment. Most of the clinicians rely on the conventional two-dimensional (2D radiographs. But being a 2D image, it has its own limitations. 2D images at times can give an incomplete picture about the severity or type of disease and can further affect the treatment plan. Cone beam computed tomography (CBCT has a better potential for detecting periodontal bone defects with accuracy. The purpose here is to describe how CBCT imaging is beneficial in accurate diagnosis and will lead to a precise treatment plan.

  12. Improved Swimming Performance in Hydrodynamically- coupled Airfoils

    Science.gov (United States)

    Heydari, Sina; Shelley, Michael J.; Kanso, Eva

    2017-11-01

    Collective motion is a widespread phenomenon in the animal kingdom from fish schools to bird flocks. Half of the known fish species are thought to exhibit schooling behavior during some phase of their life cycle. Schooling likely occurs to serve multiple purposes, including foraging for resources and protection from predators. Growing experimental and theoretical evidence supports the hypothesis that fish can benefit from the hydrodynamic interactions with their neighbors, but it is unclear whether this requires particular configurations or regulations. Here, we propose a physics-based approach that account for hydrodynamic interactions among swimmers based on the vortex sheet model. The benefit of this model is that it is scalable to a large number of swimmers. We start by examining the case of two swimmers, heaving plates, moving in parallel and in tandem. We find that for the same heaving amplitude and frequency, the coupled-swimmers move faster and more efficiently. This increase in velocity depends strongly on the configuration and separation distance between the swimmers. Our results are consistent with recent experimental findings on heaving airfoils and underline the role of fluid dynamic interactions in the collective behavior of swimmers.

  13. Coupling of smooth particle hydrodynamics with PRONTO

    Energy Technology Data Exchange (ETDEWEB)

    Attaway, S.W.; Heinstein, M.W.; Mello, F.J.; Swegle, J.W.

    1993-08-01

    A gridless numerical technique called smooth particle hydrodynamics (SPH) has been coupled to the transient dynamics finite element code, PRONTO. In this paper, a new weighted residual derivation for the SPH method will be presented, and the methods used to embed SPH within PRONTO will be outlined. Example SPH-PRONTO calculations will also be presented. One major difficulty associated with the Lagrangian finite element method is modeling materials with no shear strength; for example, gases, fluids and explosive bi-products. Typically these materials can be modeled for only a short time with a Lagrangian finite element code. Large distortions cause tangling of the mesh, which will eventually lead to numerical difficulties such as negative element area or ``bow tie`` elements. Remeshing will allow the problem to continue for a short while, but the large distortions can prevent a complete analysis. Smooth particle hydrodynamics is a gridless Lagrangian technique. Requiring no mesh, SPH has the potential to model material fracture, large shear flows, and penetration. SPH computes the strain rate and the stress divergence based on the nearest neighbors of a particle, which are determined using an efficient particle sorting technique. Embedding the SPH method within PRONTO allows part of the problem to be modeled with quadrilateral finite elements while other parts are modeled with the gridless SPH method. SPH elements are coupled to the quadrilateral elements through a contact like algorithm.

  14. Hydrodynamic Forces from Steep Waves in Rivers

    International Nuclear Information System (INIS)

    Loevoll, A.

    1996-01-01

    The reservoir behind a hydroelectric power production dam has an enormous potential for destruction in case of a dam break. The present doctoral thesis evaluates the hydrodynamic forces from steep waves in rivers. In the laboratory, forces on a structure shaped as a vertical cylinder of rectangular cross section were measured, and the threshold condition for the bed sediment was investigated. A wave parameter α is introduced to describe the gradient of a wave front. The flow condition in the flume was reproduced by a 3-D numerical model. For various values of the wave parameter the forces were measured and compared to the drag force calculated from measured depth and velocity. From these comparisons the hydrodynamic force can be calculated as drag only, even in the case of a breaking wave front. The contribution from inertia relative to drag depends on the size of the structure. For larger structures the contributions may be important in steep waves. To study the initiation of motion (of sediments) under unsteady flow, waves of various parameter values were passed over a gravel covered bed. The initiation of motion starts before the peak of the wave, and is given by Shield's relation if the friction slope is applied. No dependence upon the wave gradient was found. A relation was established which gives the critical shear stress if the friction slope is estimated by the bottom slope. 65 refs., 41 figs., 10 tabs

  15. Hydrodynamic instability experiments on the Nova laser

    International Nuclear Information System (INIS)

    Remington, B.A.; Glendinning, S.G.; Kalantar, D.H.

    1996-08-01

    Hydrodynamic instabilities in compressible plasmas play a critical role in the fields of inertial confinement fusion (ICF), astrophysics, and high energy-density physics. We are, investigating hydrodynamic instabilities such as the Rayleigh-Taylor (RT) instability, at high compression at the Nova laser in a series of experiments, both in planar and in spherical geometry. In the indirect drive approach, a thermal x-ray drive is generated by focusing the Nova laser beams into a Au cylindrical radiation cavity (hohlraum). Issues in the instability evolution that we are examining are shock propagation and foil compression, RT growth of 2D versus 3D single-mode perturbations, drive pulse shape, perturbation location at the ablation front versus at an embedded interface, and multimode perturbation growth and nonlinear saturation. The effects of convergence on RT growth are being investigated both with hemispherical implosions of packages mounted on the hohlraum wall and with spherical implosions of capsules at the center of the hohlraum. Single-mode perturbations are pre-imposed at the ablation front of these capsules as a seed for the RT growth. In our direct drive experiments, we are investigating the effect of laser imprinting and subsequent RT growth on planar foils, both at λ Laser = 1/3 μm and 1/2 μm. An overview is given describing recent progress in each of these areas

  16. Advancement in Mixing Hydrodynamics using Motionless Mixer

    Directory of Open Access Journals (Sweden)

    Mazhar Hussain

    2015-07-01

    Full Text Available A large number of scientists have been conducting research to improve the hydrodynamic characteristics of mixing of fluids. Out of these techniques, static mixing is adopted in this study to improve the mixing of fluids, which has a lead of negligible energy consumption in comparison with dynamic mixers. Air Water system have been cast-off for mixing in which reduction in pressure, energy consumed, bubble diameter and mass transfer rate was mainly taken into account to design the static mixer element. Five different types of elements (Baffle, Plate, Blade, Needle and Wheel were tested to observe and compare above mentioned hydrodynamic properties. Two point source characteristics i.e. reduction in pressure and bubble size, were carried out using Hg manometer and still photography respectively. Other nonpoint source characteristics (Energy depletion, rate of mixing were found to be directly influenced by these point source characteristics. From the experimentations baffle element catches more importance, in terms of less energy depletion, more mixing rate, when compared with the other elements tested. This element becomes also comparable with other elements renowned in literature.

  17. Hydrodynamic Forces from Steep Waves in Rivers

    Energy Technology Data Exchange (ETDEWEB)

    Loevoll, A.

    1996-12-31

    The reservoir behind a hydroelectric power production dam has an enormous potential for destruction in case of a dam break. The present doctoral thesis evaluates the hydrodynamic forces from steep waves in rivers. In the laboratory, forces on a structure shaped as a vertical cylinder of rectangular cross section were measured, and the threshold condition for the bed sediment was investigated. A wave parameter {alpha} is introduced to describe the gradient of a wave front. The flow condition in the flume was reproduced by a 3-D numerical model. For various values of the wave parameter the forces were measured and compared to the drag force calculated from measured depth and velocity. From these comparisons the hydrodynamic force can be calculated as drag only, even in the case of a breaking wave front. The contribution from inertia relative to drag depends on the size of the structure. For larger structures the contributions may be important in steep waves. To study the initiation of motion (of sediments) under unsteady flow, waves of various parameter values were passed over a gravel covered bed. The initiation of motion starts before the peak of the wave, and is given by Shield`s relation if the friction slope is applied. No dependence upon the wave gradient was found. A relation was established which gives the critical shear stress if the friction slope is estimated by the bottom slope. 65 refs., 41 figs., 10 tabs.

  18. A web portal for hydrodynamical, cosmological simulations

    Science.gov (United States)

    Ragagnin, A.; Dolag, K.; Biffi, V.; Cadolle Bel, M.; Hammer, N. J.; Krukau, A.; Petkova, M.; Steinborn, D.

    2017-07-01

    This article describes a data centre hosting a web portal for accessing and sharing the output of large, cosmological, hydro-dynamical simulations with a broad scientific community. It also allows users to receive related scientific data products by directly processing the raw simulation data on a remote computing cluster. The data centre has a multi-layer structure: a web portal, a job control layer, a computing cluster and a HPC storage system. The outer layer enables users to choose an object from the simulations. Objects can be selected by visually inspecting 2D maps of the simulation data, by performing highly compounded and elaborated queries or graphically by plotting arbitrary combinations of properties. The user can run analysis tools on a chosen object. These services allow users to run analysis tools on the raw simulation data. The job control layer is responsible for handling and performing the analysis jobs, which are executed on a computing cluster. The innermost layer is formed by a HPC storage system which hosts the large, raw simulation data. The following services are available for the users: (I) CLUSTERINSPECT visualizes properties of member galaxies of a selected galaxy cluster; (II) SIMCUT returns the raw data of a sub-volume around a selected object from a simulation, containing all the original, hydro-dynamical quantities; (III) SMAC creates idealized 2D maps of various, physical quantities and observables of a selected object; (IV) PHOX generates virtual X-ray observations with specifications of various current and upcoming instruments.

  19. Mix and hydrodynamic instabilities on NIF

    Science.gov (United States)

    Smalyuk, V. A.; Robey, H. F.; Casey, D. T.; Clark, D. S.; Döppner, T.; Haan, S. W.; Hammel, B. A.; MacPhee, A. G.; Martinez, D.; Milovich, J. L.; Peterson, J. L.; Pickworth, L.; Pino, J. E.; Raman, K.; Tipton, R.; Weber, C. R.; Baker, K. L.; Bachmann, B.; Berzak Hopkins, L. F.; Bond, E.; Caggiano, J. A.; Callahan, D. A.; Celliers, P. M.; Cerjan, C.; Dixit, S. N.; Edwards, M. J.; Felker, S.; Field, J. E.; Fittinghoff, D. N.; Gharibyan, N.; Grim, G. P.; Hamza, A. V.; Hatarik, R.; Hohenberger, M.; Hsing, W. W.; Hurricane, O. A.; Jancaitis, K. S.; Jones, O. S.; Khan, S.; Kroll, J. J.; Lafortune, K. N.; Landen, O. L.; Ma, T.; MacGowan, B. J.; Masse, L.; Moore, A. S.; Nagel, S. R.; Nikroo, A.; Pak, A.; Patel, P. K.; Remington, B. A.; Sayre, D. B.; Spears, B. K.; Stadermann, M.; Tommasini, R.; Widmayer, C. C.; Yeamans, C. B.; Crippen, J.; Farrell, M.; Giraldez, E.; Rice, N.; Wilde, C. H.; Volegov, P. L.; Gatu Johnson, M.

    2017-06-01

    Several new platforms have been developed to experimentally measure hydrodynamic instabilities in all phases of indirect-drive, inertial confinement fusion implosions on National Ignition Facility. At the ablation front, instability growth of pre-imposed modulations was measured with a face-on, x-ray radiography platform in the linear regime using the Hydrodynamic Growth Radiography (HGR) platform. Modulation growth of "native roughness" modulations and engineering features (fill tubes and capsule support membranes) were measured in conditions relevant to layered DT implosions. A new experimental platform was developed to measure instability growth at the ablator-ice interface. In the deceleration phase of implosions, several experimental platforms were developed to measure both low-mode asymmetries and high-mode perturbations near peak compression with x-ray and nuclear techniques. In one innovative technique, the self-emission from the hot spot was enhanced with argon dopant to "self-backlight" the shell in-flight. To stabilize instability growth, new "adiabat-shaping" techniques were developed using the HGR platform and applied in layered DT implosions.

  20. On Hydrodynamic Instabilities in Cylindrical Geometry

    Science.gov (United States)

    Proano, Erik; Rollin, Bertrand

    2017-11-01

    Recent research has suggested that hydrodynamic instabilities induced mixing is one of the last major hurdles toward achieving optimum conditions for ignition in confined fusion approaches for energy production. We leave aside the complexities of multiple interacting physics that lead to a fusion target ignition to be able to focus on understanding the development of these hydrodynamic instabilities, namely Richtmyer-Meshkov and Rayleigh-Taylor, in the context of a converging geometry. The problem is reformulated into the cleaner case of a cylindrical shock wave imploding onto a pocket of Sulfur Hexafluoride immersed in air. This numerical experiment aims at characterizing qualitatively and quantitatively the relation between the instabilities initial conditions and their development until late time. Starting from carefully designed single- and multimode disturbances at the initial density interface, our simulations track the evolution of the mixing layer through successive occurrences of the Richtmyer-Meshkov and Rayleigh-Taylor instabilities. Evolution of the mixing zone width and growth rate are presented for selected initial conditions, along with a quantification of mixing. Also, the effect of the converging shock strength is discussed.

  1. Mesoscale simulations of hydrodynamic squirmer interactions.

    Science.gov (United States)

    Götze, Ingo O; Gompper, Gerhard

    2010-10-01

    The swimming behavior of self-propelled microorganisms is studied by particle-based mesoscale simulations. The simulation technique includes both hydrodynamics and thermal fluctuations that are both essential for the dynamics of microswimmers. The swimmers are modeled as squirmers, i.e., spherical objects with a prescribed tangential surface velocity, where the focus of thrust generation can be tuned from pushers to pullers. For passive squirmers (colloids), we show that the velocity autocorrelation function agrees quantitatively with the Boussinesq approximation. Single active squirmers show a persistent random-walk behavior, determined by forward motion, lateral diffusion, and orientational fluctuations, in agreement with theoretical predictions. For pairs of squirmers, which are initially swimming in parallel, we find an attraction for pushers and a repulsion for pullers, as expected. The hydrodynamic force between squirmer pairs is calculated as a function of the center-to-center distances d(cm) and is found to be consistent with a logarithmic distance dependence for d(cm) less than about two sphere diameters; here, the force is considerably stronger than expected from the far-field expansion. The dependence of the force strength on the asymmetry of the polar surface velocity is obtained. During the collision process, thermal fluctuations turn out to be very important and to strongly affect the postcollision velocity directions of both squirmers.

  2. Radiographic evaluation of coxofemoral joint laxity in dogs part I: New stress-radiographic positioning techniques

    International Nuclear Information System (INIS)

    Phiwipha Kamonrat; Duangdaun Kaenkangploo

    2002-01-01

    Two new stress-radiographic positioning techniques, namely 60 deg and 90 deg stress techniques, were introduced for quantifying hip joint laxity in dogs. The comparative characteristics and efficiency of these new techniques with angled hindlimbs were evaluated relative to the standard hip-extended radiographic technique. Forty, healthy, mongrel dogs with normal hip joint conformation were anesthetized and placed in dorsal recumbency before 3 radiograhps of the standard, 60 deg , and 90 deg stress techniques were taken. For the 60 deg stress technique, hindlimbs were extended in parallel to each other at 60 deg angled to the table top and stifles were slightly rotated inward, femoral heads were manually pushed in a craniodorsal direction during exposure. For the 90 deg stress technique, femurs were positioned perpendicular to the table top, stifles were 90 deg flexed and adducted and femoral heads were manually pushed in a craniodorsal direction during exposure. The subluxation index (SI) and dorsolateral subluxation score (DLS score) were calculated from 3 radiographic views for both hip joints to quantitate the relative degree of joint laxity. Results of the study indicated that the 60 deg (SI = 0.20+-0.045, DLS score = 62.5+-7.96 percent) and 90 deg (SI = 0.23+-0.044, DLS score = 61.2+-9.47 percent) stress-radiographs yielded significantly (p0.001) higher degree of hip joint laxity than the standard technique (SI)

  3. Commitment of the radiographer - does it matter to the patient?

    International Nuclear Information System (INIS)

    Blagoeva, D.; Shuleva, L.; Goudeva, V.; Stoinova, V.

    2015-01-01

    Full text: Radiographers are responsible for providing safe and accurate imaging examinations in a wide range of clinical environments, using a variety of imaging modalities and techniques so that appropriate management and treatment of patients and clients can proceed. The purpose of this presentation is to discuss: the responsibilities of radiographer in the clinical radiology department; their professional judgment to decide how to achieve a diagnostic outcome; the relationship patient/radiographer; the impact of the radiographer on patient care. Patient care and advocacy has always been an integral part of the radiography profession. The radiographer should respect the patient at all the times, be genuine in nature and empathies with the patient‘s condition. Good listening and observational skills are also very important components. The radiographers are personally accountable for their work and professional conduct

  4. Pelvic tilt and truncal inclination: two key radiographic parameters in the setting of adults with spinal deformity.

    Science.gov (United States)

    Lafage, Virginie; Schwab, Frank; Patel, Ashish; Hawkinson, Nicola; Farcy, Jean-Pierre

    2009-08-01

    Prospective radiographic and clinical analysis. Investigate the relationship between spino-pelvic parameters and patient self reported outcomes on adult subjects with spinal deformities. It is becoming increasingly recognized that the study of spinal alignment should include pelvic position. While pelvic incidence determines lumbar lordosis, pelvic tilt (PT) is a positional parameter reflecting compensation to spinal deformity. Correlation between plumbline offset (sagittal vertical axis [SVA]) and Health Related Quality of Life (HRQOL) measures has been demonstrated, but such a study is lacking for PT. This prospective study was carried out on 125 adult patients suffering from spinal deformity (mean age: 57 years). Full-length free-standing radiographs including the spine and pelvis were available for all patients. HRQOL instruments included: Oswestry Disability Index, Short Form-12, Scoliosis Research Society. Correlation analysis between radiographic spinopelvic parameters and HRQOL measures was pursued. Correlation analysis revealed no significance pertaining to coronal plane parameters. Significant sagittal plane correlations were identified. SVA and truncal inclination measured by T1 spinopelvic inclination (T1-SPI) (angle between T1-hip axis and vertical) correlated with: Scoliosis Research Society (appearance, activity, total score), Oswestry Disability Index, and Short Form-12 (physical component score). Correlation coefficients ranged from 0.42 < r < 0.55 (P < 0.0001). T1-SPI revealed greater correlation with HRQOL compared to SVA. PT showed correlation with HRQOL (0.28 < r < 0.42) and with SVA (r = 0.64, P < 0.0001). This study confirms that pelvic position measured via PT correlates with HRQOL in the setting of adult deformity. High values of PT express compensatory pelvic retroversion for sagittal spinal malalignment. This study also demonstrates significant T1-SPI correlation with HRQOL measures and outperforms SVA. This parameter carries the

  5. Occupational stress and its predictors in radiographers

    International Nuclear Information System (INIS)

    Rutter, D.R.; Lovegrove, M.J.

    2008-01-01

    Purpose: The purpose of this study was to establish the level of occupational stress in UK NHS radiographers, and to examine its causes. A total of more than 1600 radiographers sampled nationally completed a postal questionnaire. Four groups were represented - mammography, diagnostics, radiotherapy, and ultrasound - and both junior staff and superintendents were examined. Method: The questionnaire measured role ambiguity, role conflict, work problems, social support from colleagues, and perceived stress. Results: Levels of perceived stress were high in all four groups. The mean was significantly lower in the mammography group than the others, however, and junior staff reported lower levels than superintendents. Role ambiguity, role conflict and work problems all contributed significantly to stress, but the effects were sometimes buffered by social support from colleagues. Conclusion: The implications of the findings are discussed for theory and for policy and practice: occupational stress was predicted by intrinsic features of the job; the levels were similar to those reported by other NHS professionals; and the pattern of findings suggests possible ways to intervene to reduce it

  6. Pixel Strength and Digitization of Radiographs

    Directory of Open Access Journals (Sweden)

    B Aarthi

    2007-01-01

    Full Text Available We performed a pilot study to compare the digitized images of panoramic radiographs with the original film images for perceived clarity and diagnostic quality, and to make comparison amongst the digitized film images captured by a digital camera at different resolution settings to assess if differences in clarity and/or diagnostic quality existed. Eight orthopantomograms were photographed using a digital camera, Nikon Finepix S7000, at four different resolution settings - 1 M pix, 3 M pix, 6M pix and 12 M pix respectively. These thirty two digital images were transferred to a laptop computer, Acer Travelmate 290 E, saved as JPEG files and viewed using ′Planmeca Dimaxis′ software. Five observers made comparison between the film and digitized images and also amongst the images digitized with various pixel strengths. Images were ranked for clarity and diagnostic quality. Data was analyzed using statistical tests. Results indicated no significant difference in clarity and diagnostic quality between conventional radiographs and their corresponding digitized images. The images digitized with the highest resolution were better than those digitized with the other lower resolutions.

  7. Radiographic arthrosis after elbow trauma: interobserver reliability.

    Science.gov (United States)

    Lindenhovius, Anneluuk; Karanicolas, Paul Jack; Bhandari, Mohit; Ring, David

    2012-04-01

    This study measured observer variation in radiographic rating of elbow arthrosis. Thirty-seven independent orthopedic surgeons graded the extent of elbow arthrosis in 20 consecutive sets of plain radiographs, according to the Broberg and Morrey rating system (grade 0, normal joint; grade 1, slight joint-space narrowing with minimum osteophyte formation; grade 2, moderate joint-space narrowing with moderate osteophyte formation; and grade 3, severe degenerative change with gross destruction of the joint). The kappa multirater measure (κ) was used to estimate reliability between observers, with 0 indicating no agreement above chance, and 1 indicating perfect agreement. There was fair agreement in arthrosis ratings between surgeons. Surgeons with more than 10 years of experience had greater agreement than did surgeons with less experience, and surgeons who treated more than 10 elbow fractures per year had better agreement than did those treating fewer fractures. In post hoc analyses, 2 simplified binary rating systems (eg, "none or mild" vs "moderate or severe" arthrosis) resulted in moderate agreement among observers. The 4 grades of the Broberg and Morrey classification system have only fair interobserver reliability that is influenced by subspecialty and experience. Binary rating systems might be more reliable. Diagnostic III. Copyright © 2012 American Society for Surgery of the Hand. All rights reserved.

  8. Monte Carlo simulation for radiographic applications

    International Nuclear Information System (INIS)

    Tillack, G.R.; Bellon, C.

    2003-01-01

    Standard radiography simulators are based on the attenuation law complemented by built-up-factors (BUF) to describe the interaction of radiation with material. The assumption of BUF implies that scattered radiation reduces only the contrast in radiographic images. This simplification holds for a wide range of applications like weld inspection as known from practical experience. But only a detailed description of the different underlying interaction mechanisms is capable to explain effects like mottling or others that every radiographer has experienced in practice. The application of Monte Carlo models is capable to handle primary and secondary interaction mechanisms contributing to the image formation process like photon interactions (absorption, incoherent and coherent scattering including electron-binding effects, pair production) and electron interactions (electron tracing including X-Ray fluorescence and Bremsstrahlung production). It opens up possibilities like the separation of influencing factors and the understanding of the functioning of intensifying screen used in film radiography. The paper discusses the opportunities in applying the Monte Carlo method to investigate special features in radiography in terms of selected examples. (orig.) [de

  9. Necrotizing fasciitis : plain radiographic and CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Dae; Park, Jeong Hee; Jeon, Hae Jeong; Lim, Jong Nam; Heo, Tae Haeng; Park, Dong Rib [Konkuk Univ. College of Medicine, Seoul (Korea, Republic of)

    1996-11-01

    To evaluate the plain radiographic and CT findings of the necrotizing fasciitis. We retrospectively reviewed the radiologic findings of 4 cases with necrotizing fasciitis. Three cases were proven pathologically. We evaluated pattern and extent of the gas shadows in plain films. CT findings were analysed, with emphasis on : (a) gas pattern, (b) extent, (c) location and involved site, (d) associated focal abscess, and (e) swelling of the adjacent muscles. On plain radiographs, four cases showed streaky or mottled gas densities in the pelvis, three cases in the perineum, one case in the abdomen, and two cases in the thigh. On CT images, gas pattern was mottled and streaky appearance with swelling of the adjacent muscles. Gas shadows located in the extraperitoneal space in four cases, fascial layer in four cases, and subcutaneous layer in four cases. There were gas shadows in pelvic wall, perineum, abdominal wall, buttock, thigh, and scrotum. Focal low density lesion suggestive of focal abscess was not visualized. Plain radiography is useful for early diagnosis of the necrotizing fasciitis and CT is very useful for detection of precise location and extent of the disease. CT is also useful for differentiation of necrotizing fasciitis from focal abscess and cellulitis.

  10. MRI and radiographic findings in Currarino's triad

    International Nuclear Information System (INIS)

    Pfluger, T.; Czekalla, R.; Koletzko, S.; Muensterer, O.; Willemsen, U.F.; Hahn, K.

    1996-01-01

    Currarino's triad is a rare complex of a congential sacral bony abnormality, anorectal malformation and a presacral mass. Intractable constipation since birth is the leading symptom of this triad, which follows an autosomal dominant mode of heredity. We report conventional radiographic and MR findings in one family consisting of a mother and her two daughters. In all three cases, radiography revealed an abnormality of the os sacrum, the so-called scimitar sacrum. MR examination, undertaken next in our institution, was applied with T1-, T2- and proton density weighted sequences in all three orientations before and after i.v. application of gadolinium diethylene-triamine-pentaacetic acid (Gd-DTPA). In two patients we were able to diagnose the complete form of the triad and in one patient an incomplete form. In any case of a radiographically diagnosed scimitar sacrum in combination with constipation. Currarino's triad should be considered. MRI, as the method of choice, should be the next step to detect a presacral mass and any anomalies of the spinal canal. The importance of early recognition lies in the high morbidity and mortality rates resulting from this disorder. (orig.)

  11. Xeroradiographic and radiographic anatomy of the channel catfish, Ictalurus punctatus

    International Nuclear Information System (INIS)

    Smith, S.A.; Smith, B.J.

    1994-01-01

    The purpose of this study was to provide an anatomic reference for the channel catfish (Ictalurus punctatus) using xeroradiography† and conventional radiography. The entire body of three adult fish was radiographed using standard xeroradiographic and conventional radiographic techniques. Two xeroradiographs and their corresponding conventional radiographs were selected, and the xeroradiographs labeled to illustrate the normal skeletal and soft-tissue anatomy of the channel catfish

  12. Radiographic evaluation for inspection of steel casting and welding parts

    International Nuclear Information System (INIS)

    Bilge, A.N.; Tugrul, B.

    1986-01-01

    Evaluation of the radiographs is an important stage of the radiography technique. In this study,the basis of the evaluation are defined and related international references are given with examples. Radiographic inspections for steel casting and welding parts are expanded applications. In Turkey,industrial quality controls are realized mostly on this type of the materials. The important points and different types of the discontinuities are explained with some radiographs. (author)

  13. Automated result analysis in radiographic testing of NPPs' welded joints

    International Nuclear Information System (INIS)

    Skomorokhov, A.O.; Nakhabov, A.V.; Belousov, P.A.

    2009-01-01

    The article presents development results of algorithms for automated image interpretation of NPP welded joints radiographic inspection. The developed algorithms are based on state-of-the-art pattern recognition methods. The paper covers automatic radiographic image segmentation, defects detection and their parameters evaluation issues. The developed algorithms testing results for actual radiographic images of welded joints with significant variation of defects parameters are given [ru

  14. Radiographic analysis of partial or total vertebral body resection

    International Nuclear Information System (INIS)

    Whitten, C.G.; Hammer, G.H.; El-Khoury, G.Y.; Hugus, J.; Weinstein, J.N.

    1991-01-01

    Partial and total vertebrectomies are used in the treatment of primary and metastatic neoplasms of the spine. Serial radiographic studies are crucial in the follow-up of patients with vertebrectomies. This paper presents 33 cases and illustrates radiographic examples of both successful and complicated vertebrectomies, including radiographic signs of local tumor recurrence, loosening, migration or fracture of the hardware or methylmethacrylate, bone graft failure, and progressive spinal instability

  15. Reflections on the role of consultant radiographers in the UK: What is a consultant radiographer?

    International Nuclear Information System (INIS)

    Booth, L.; Henwood, S.; Miller, P.

    2016-01-01

    Context: This paper is the second paper from a two year in depth case study, exploring the role of consultant radiographers in the UK. Methods: A longitudinal case study approach was used to determine the role of consultant radiographers. Interviews were used to explore experiences of being a consultant, which were analysed using thematic analysis. Eight consultant radiographers participated (Note, two of the consultants withdrew after the first interview due to workload). Therefore two consultants were interviewed only once. The remaining six consultants were interviewed twice over a 12 month period. Findings: The data presented in this paper explores the nature of the role, differences between roles, the four domains of practice, and how the role fits into local organisational structures. The study shows wide variation in the types of roles undertaken, reflecting that the creation of these roles were in response to local clinical need and often related to an individual practitioner's skills. The broad scope of the role was shown across all the consultants, with evidence of roles developing into new areas of service delivery. Conclusions: The paper offers insight into the role(s) of consultant radiographers in the UK. The range and scope of their practice is extensive, with much variation. It is evident that the clinical aspect of the role dominates, with research being the least supported domain of practice. There remains a lack of clarity around the role, with concerns about remuneration and other limitations that may restrict the role developing further. - Highlights: • This paper shows the variation in roles between consultant radiographers. • The commonality with medical roles is highlighted. • Problem solving is identified as a core skill in consultant radiography. • Consultants offered evidence of the roles developing service provision. • While all four domains of practice are covered, research is the least well supported.

  16. Accuracy of dental radiographs for caries detection.

    Science.gov (United States)

    Keenan, James R; Keenan, Analia Veitz

    2016-06-01

    Data sourcesMedline, Embase, Cochrane Central and grey literature, complemented by cross-referencing from bibliographies. Diagnostic reviews were searched using the Medion database.Study selectionStudies reporting on the accuracy (sensitivity/specificity) of radiographic detection of primary carious lesions under clinical (in vivo) or in vitro conditions were included. The outcome of interest was caries detection using radiographs. The study also assessed the effect of the histologic lesion stage and included articles to assess the differences between primary or permanent teeth, if there had been improvements recently due to technical advances or radiographic methods, or if there are variations within studies (between examiners or applied radiographic techniques).Data extraction and synthesisData extraction was done by one reviewer first, using a piloted electronic spreadsheet and repeated independently by a second reviewer. Consensus was achieved by discussion. Data extraction followed guidelines from the Cochrane Collaboration. Risk of bias was assessed using QUADAS-2. Pooled sensitivity, specificity and diagnostic odds ratios (DORs) were calculated using random effects meta-analysis. Analyses were performed separately for occlusal and proximal lesions. Dentine lesions and cavitated lesions were analysed separately.Results947 articles were identified with the searches and 442 were analysed full text. 117 studies (13,375 teeth, 19,108 surfaces) were included. All studies were published in English. 24 studies were in vivo and 93 studies were in vitro. Risk of bias was found to be low in 23 and high in 94 studies. The pooled sensitivity for detecting any kind of occlusal carious lesions was 0.35 (95% CI : 0.31/40) and 0.41 (0.39/0.44) in clinical and in vitro studies respectively while the pooled specificity was 0.78 (0.73/0.83) and 0.70 (0.76/0.84). For the detection of any kind of proximal lesion the sensitivity in the clinical studies was 0.24 (CI 0.21/0/26) and

  17. Common pitfalls in radiographic interpretation of the Thorax

    International Nuclear Information System (INIS)

    Godshalk, C.P.

    1994-01-01

    Errors in radiographic interpretation of the thorax are common. Many mistakes result from interpreting normal anatomic variants as abnormalstructures, such as misdiagnosing dorsal and rightward deviation of the cranial thoracic trachea on lateral radiographs of normal dogs. Some of the more common errors specifically relate to misinterpretation of radiographs made on obese patients. The age of the patient also plays a role in misdiagnosis. Aging cats seem to have a horizontally positioned heart on lateral radiographs, and older dogs, primarily collies,often have pulmonary osteomas that are misdiagnosed as metastatic neoplastic disease or healed pulmonary fungal infections

  18. Radiographic stents: integrating treatment planning and implant placement.

    Science.gov (United States)

    De Kok, Ingeborg J; Thalji, Ghadeer; Bryington, Matthew; Cooper, Lyndon F

    2014-01-01

    The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. Radiographic planning for dental implant therapy should be used only after a review of the patient's systemic health, imaging history, oral health, and local oral conditions. The radiological diagnostic and planning procedure for dental implants can only be fully achieved with the use of a well-designed and -constructed radiographic guide. This article reviews several methods for construction of radiographic guides and how they may be utilized for improving implant surgery planning and performance. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Radiographic caries diagnosis and restorative treatment decision making

    International Nuclear Information System (INIS)

    Mileman, P.A.

    1985-01-01

    This thesis is concerned with a single diagnostic technique: the bitewing radiograph, and the way it is used by dentists to decide on patient treatment need for interproximal caries. The variation in caries diagnosis and treatment decisions using bitewing radiographs is described and the radiographic criteria of choice for minimizing over and undertreatment according to a norm are investigated. Three possible diagnostic strategies in interproximal caries diagnosis using a decision analysis approach are described and evaluated, and the effect of the reported diagnostic behaviour and knowledge of practicing Dutch dentists in their use of bitewing radiographs for the diagnosis and treatment of interproximal caries is described and analyzed. (Auth.)

  20. Radiographic anatomy of the medial coronoid process of dogs

    International Nuclear Information System (INIS)

    Miyabayashi, T.; Takiguchi, M.; Schrader, S.C.; Biller, D.S.

    1995-01-01

    Mediolateral, flexed mediolateral, mediocaudal-laterocranial 15 degrees oblique (extended and supinated mediolateral), and craniolateral-caudomedial 20 degrees to 30 degrees oblique radiographs of 16 elbow-joint specimens were produced to study the radiographic anatomy of the medial coronoid process. On the mediolateral view, the cranial point of the coronoid process was at the level of the distal one-third of the radial epiphysis. Degree of superimposition of the proximal radius and ulna determined how the medial coronoid process was projected on the radiographs. Mediocaudal-laterocranial oblique radiographs best showed the cranial outline of the medial coronoid process with moderate superimposition of the proximal radius and ulna

  1. FABM-PCLake – linking aquatic ecology with hydrodynamics

    DEFF Research Database (Denmark)

    Hu, Fenjuan; Bolding, Karsten; Bruggeman, Jorn

    2016-01-01

    -PCLake represents an integrated aquatic ecosystem model that can be linked with different hydrodynamic models and allows simulations of hydrodynamic and biogeochemical processes for zero-dimensional, one-dimensional as well as three-dimensional environments. FABM-PCLake describes interactions between multiple...

  2. Three aspects of critical phenomenons: fundamental, hydrodynamic, conceptual

    International Nuclear Information System (INIS)

    Beysens, D.

    1993-01-01

    After a recall of the leading results relative to the universality class of fluids, examples of how well known universal prevision are held in check by fluids specificities, especially hydrodynamics. Applications of critical phenomenons tool to damping, hydrodynamic instabilities, turbulence are described. (A.B.). 11 refs., 7 figs., 1 tab

  3. Flow hydrodynamics near inlet key of Piano Key Weir (PKW)

    Indian Academy of Sciences (India)

    This paper presents fundamental outcomes from an experimental study on the hydrodynamic performance near inlet key of Piano Key Weir (PKW). Hydrodynamic performance was tested in a circulated open channel that comprised of PKW and sand bed (d50 = 0.25 mm). Instantaneous velocities were measured at 20 cross ...

  4. Measuring and modelling overwash hydrodynamics on a barrier island

    NARCIS (Netherlands)

    Matias, Ana; Carrasco, Ana Rita; Loureiro, Carlos; Andriolo, Umberto; Masselink, Gerd; Guerreiro, Martha; Pacheco, A; McCall, R.T.; Ferreira, Óscar; Plomaritis, Theocharis A.; Aagaard, T.; Deigaard, R.; Fuhrman, D.

    2017-01-01

    Overwash hydrodynamics datasets are mixed in quality and scope, being hard to obtain due to fieldwork experimental difficulties. Aiming to overcome such limitations, this work presents accurate fieldwork data on overwash
    hydrodynamics, further exploring it to model overwash on a low-lying

  5. Finite element analysis of one–dimensional hydrodynamic ...

    African Journals Online (AJOL)

    In this research work, we consider the one dimensional hydrodynamic dispersion of a reactive solute in electroosmotic flow. We present results demonstrating the utility of finite element methods to simulate and visualize hydrodynamic dispersion in the electroosmotic flow. From examination of concentration profile, effective ...

  6. Divorticity and dihelicity in two-dimensional hydrodynamics

    DEFF Research Database (Denmark)

    Shivamoggi, B.K.; van Heijst, G.J.F.; Juul Rasmussen, Jens

    2010-01-01

    A framework is developed based on the concepts of divorticity B (≡×ω, ω being the vorticity) and dihelicity g (≡vB) for discussing the theoretical structure underlying two-dimensional (2D) hydrodynamics. This formulation leads to the global and Lagrange invariants that could impose significant...... constraints on the evolution of divorticity lines in 2D hydrodynamics....

  7. The use of hydrodynamic disintegration as a means to improve ...

    African Journals Online (AJOL)

    Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are immediately available for biological ...

  8. Hydrodynamic cavitation: a bottom-up approach to liquid aeration

    NARCIS (Netherlands)

    Raut, J.S.; Stoyanov, S.D.; Duggal, C.; Pelan, E.G.; Arnaudov, L.N.; Naik, V.M.

    2012-01-01

    We report the use of hydrodynamic cavitation as a novel, bottom-up method for continuous creation of foams comprising of air microbubbles in aqueous systems containing surface active ingredients, like proteins or particles. The hydrodynamic cavitation was created using a converging-diverging nozzle.

  9. Aeroelastically coupled blades for vertical axis wind turbines

    Science.gov (United States)

    Paquette, Joshua; Barone, Matthew F.

    2016-02-23

    Various technologies described herein pertain to a vertical axis wind turbine blade configured to rotate about a rotation axis. The vertical axis wind turbine blade includes at least an attachment segment, a rear swept segment, and optionally, a forward swept segment. The attachment segment is contiguous with the forward swept segment, and the forward swept segment is contiguous with the rear swept segment. The attachment segment includes a first portion of a centroid axis, the forward swept segment includes a second portion of the centroid axis, and the rear swept segment includes a third portion of the centroid axis. The second portion of the centroid axis is angularly displaced ahead of the first portion of the centroid axis and the third portion of the centroid axis is angularly displaced behind the first portion of the centroid axis in the direction of rotation about the rotation axis.

  10. Role Played by Shear-Induced Hydrodynamic Diffusion on the Continuous Separation of Blood Cells

    Science.gov (United States)

    Hoyos, Mauricio; Kurowski, Pascal; Moore, Lee; Williams, Stephen; Zborowski, Maciej

    2001-11-01

    The continuous sorting of hematopoietic stem cells, lymphocytes or other blood cells can be performed using a membraneless hydrodynamic technique called split-flow thin channel fractionation, SPLITT. Two streams are introduced to the separator: carrier at one inlet and a suspension containing a mixture of immunomagnetically-labeled cells and unlabeled cells at the other inlet. The SPLITT channel, comprising a thin annulus between two concentric cylinders, is fitted into a permanent quadrupole magnet. The sample is transported along the axis of the separation column, and the labeled cells migrate perpendicular to the bulk flow under the influence of the magnetic field. The aim is to recover - at high purity - all of the magnetized cells in the enriched outlet. However, other cells contaminate the enriched fraction. This may be due to a transversal transport of non-immunomagnetically-labeled cells - termed crossover - by shear-induced hydrodynamic diffusion, SIHD, occurring along the separator. The unwanted cell crossover strongly influences the target cell purity in the enriched fraction. We investigate the possible presence of SIHD on the separation of progenitor cells and particles by studying the cross-stream concentration as a function of different parameters: namely, shear rate, inlet concentration and particle size. With our SIHD model we can solve the convection-diffusion equation by assuming an effective diffusion coefficient, which predicts the observed crossover.

  11. Fractionation of Magnetic Microspheres in a Microfluidic Spiral: Interplay between Magnetic and Hydrodynamic Forces.

    Directory of Open Access Journals (Sweden)

    S Dutz

    Full Text Available Magnetic forces and curvature-induced hydrodynamic drag have both been studied and employed in continuous microfluidic particle separation and enrichment schemes. Here we combine the two. We investigate consequences of applying an outwardly directed magnetic force to a dilute suspension of magnetic microspheres circulating in a spiral microfluidic channel. This force is realized with an array of permanent magnets arranged to produce a magnetic field with octupolar symmetry about the spiral axis. At low flow rates particles cluster around an apparent streamline of the flow near the outer wall of the turn. At high flow rates this equilibrium is disrupted by the induced secondary (Dean flow and a new equilibrium is established near the inner wall of the turn. A model incorporating key forces involved in establishing these equilibria is described, and is used to extract quantitative information about the magnitude of local Dean drag forces from experimental data. Steady-state fractionation of suspensions by particle size under the combined influence of magnetic and hydrodynamic forces is demonstrated. Extensions of this work could lead to new continuous microscale particle sorting and enrichment processes with improved fidelity and specificity.

  12. Vertical and horizontal location of the mental foramen in relation to the mandibular second premolar by the radiograph method

    Directory of Open Access Journals (Sweden)

    Felipe Paes Varoli

    2008-01-01

    Full Text Available Objective: Measure the distance in millimeters, between the apex and the long axis of the mandibular second premolar and the mental foramen. Methods: One hundred and four panoramic radiographs of adults with teeth were selected. Measurement was performed by digitizing the radiographs. The “Image Tool 1.28” program was used to identify the distances. The data of 67 radiographs out of the total, whose visualization of the foramen on the right and left sides was considered good, were submitted to the Student’s-t test and Wilcoxon Sign Test Sinais de Postos de Wilcoxon with a=5%. Results: Analyzing the distance from the long axis to the foramen in the 104 radiographs, it was found located at the medial, 73.34% on the right and 69.04% on the left, being the highest percentages. In the distance between the apex and the foramen, the two sides wererelated, t(t=1.07; gl=66; p=0.288, on the right being (median; mean±standard deviation: 4.73; 4.88±3.46 and on the left (5.45;5.23±3.68 and from the long axis to the foramen, relating the sides, parametric (t=1.98; gl=66; p=0.051 and non-parametric (p=0.081, indicating on the right (median; mean±standard deviation: 4.02; 3.81±4.03 and on the left (3.79; 2.78±4.15. The results indicated that the mental foramen was presented medially to the 2nd premolar, being correspondent to the sides, both to a mean of, right, 4.88mm from the apex and 3.81 mm in the mesial direction; and left, 5.23mm from the apex and 2.78mm in the mesial direction. Conclusion: It could be concluded that both the distance from the apex and from the long axis did not differ statistically toward the right and left.

  13. Hydrodynamic Coefficients Identification and Experimental Investigation for an Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Shaorong XIE

    2014-02-01

    Full Text Available Hydrodynamic coefficients are the foundation of unmanned underwater vehicles modeling and controller design. In order to reduce identification complexity and acquire necessary hydrodynamic coefficients for controllers design, the motion of the unmanned underwater vehicle was separated into vertical motion and horizontal motion models. Hydrodynamic coefficients were regarded as mapping parameters from input forces and moments to output velocities and acceleration of the unmanned underwater vehicle. The motion models of the unmanned underwater vehicle were nonlinear and Genetic Algorithm was adopted to identify those hydrodynamic coefficients. To verify the identification quality, velocities and acceleration of the unmanned underwater vehicle was measured using inertial sensor under the same conditions as Genetic Algorithm identification. Curves similarity between measured velocities and acceleration and those identified by Genetic Algorithm were used as optimizing standard. It is found that the curves similarity were high and identified hydrodynamic coefficients of the unmanned underwater vehicle satisfied the measured motion states well.

  14. Theoretical tool movement required to diamond turn an off-axis paraboloid on axis

    International Nuclear Information System (INIS)

    Thompson, D.C.

    1976-01-01

    Current techniques for manufacturing off-axis paraboloids are both expensive and insufficiently accurate. An alternative method, turning the workpiece about its axis on a diamond-turning machine, is presented, and the equations describing the necessary tool movement are derived. A discussion of a particular case suggests that the proposed technique is feasible

  15. Modular off-axis solar concentrator

    Science.gov (United States)

    Plesniak, Adam P; Hall, John C

    2015-01-27

    A solar concentrator including a housing defining a vertical axis and including a receiving wall connected to a reflecting wall to define an internal volume and an opening into the internal volume, wherein the reflecting wall defines at least one primary optical element, and wherein at least a portion of the reflecting wall includes a layer of reflective material, the housing further including a cover connected to the receiving wall and the reflecting wall to seal the opening, and at least one receiver mounted on the receiving wall such that a vertical axis of the receiver is disposed at a non-zero angle relative to the vertical axis of the housing, the receiver including at least one photovoltaic cell.

  16. Enclosed, off-axis solar concentrator

    Science.gov (United States)

    Benitez, Pablo; Grip, Robert E; Minano, Juan C; Narayanan, Authi A; Plesniak, Adam; Schwartz, Joel A

    2013-11-26

    A solar concentrator including a housing having receiving wall, a reflecting wall and at least two end walls, the receiving, reflecting and end walls defining a three-dimensional volume having an inlet, wherein a vertical axis of the housing is generally perpendicular to the inlet, a receiver mounted on the receiving wall of the housing, the receiver including at least one photovoltaic cell, wherein a vertical axis of the receiver is disposed at a non-zero angle relative to the vertical axis of the housing, at least one clip disposed on the reflecting wall an optical element received within the three-dimensional volume, the optical element including at least one tab, the tab being engaged by the clip to align the optical element with the receiver, and a window received over the inlet to enclose the housing.

  17. An analysis of smoothed particle hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Swegle, J.W.; Attaway, S.W.; Heinstein, M.W.; Mello, F.J. [Sandia National Labs., Albuquerque, NM (United States); Hicks, D.L. [Michigan Technological Univ., Houghton, MI (United States)

    1994-03-01

    SPH (Smoothed Particle Hydrodynamics) is a gridless Lagrangian technique which is appealing as a possible alternative to numerical techniques currently used to analyze high deformation impulsive loading events. In the present study, the SPH algorithm has been subjected to detailed testing and analysis to determine its applicability in the field of solid dynamics. An important result of the work is a rigorous von Neumann stability analysis which provides a simple criterion for the stability or instability of the method in terms of the stress state and the second derivative of the kernel function. Instability, which typically occurs only for solids in tension, results not from the numerical time integration algorithm, but because the SPH algorithm creates an effective stress with a negative modulus. The analysis provides insight into possible methods for removing the instability. Also, SPH has been coupled into the transient dynamics finite element code PRONTO, and a weighted residual derivation of the SPH equations has been obtained.

  18. Using river locks to teach hydrodynamic concepts

    International Nuclear Information System (INIS)

    Carvalho-Santos, Vagson L; Mendes, Thales C; Silva, Enisvaldo C; Rios, Márcio L; Silva, Anderson A P

    2013-01-01

    In this work, the use of a river lock as a non-formal setting for teaching hydrodynamical concepts is proposed. In particular, we describe the operation of a river lock situated at the Sobradinho dam, on the São Francisco River (Brazil). A model to represent and to analyse the dynamics of river lock operation is presented and we derive the dynamical equations for the rising of the water column as an example to understand the Euler equation. Furthermore, with this activity, we enable the integration of content initially introduced in the classroom with practical applications, thereby allowing the association of physical themes to content relevant in disciplines such as history and geography. In addition, experiences of this kind enable teachers to talk about the environmental and social impacts caused by the construction of a dam and, consequently, a crossover of concepts has been made possible, leading to more meaningful learning for the students. (paper)

  19. Hydrodynamics of primordial black hole formation

    Science.gov (United States)

    Nadezhin, D. K.; Novikov, I. D.; Polnarev, A. G.

    1979-01-01

    The hydrodynamic picture of the formation of primordial black holes (PBH) at the early stages of expansion of the Universe is considered. It is assumed that close to singularity, expansion occurs in a quasi-isotropic way. Using an EVM, a spherically symmetrical nonlinear problem of the evolution of primary strong deviation from the Fridman solution was solved. What these deviations must be, so that the formation of PBH occurred was clarified. Attention was devoted to the role of pressure gradients. It is pointed out that at the moment of formation of PBH, only a small part of matter enters into it, primarily the component of perturbation. It is also pointed out that at this moment, the mass of PBH essentially is smaller than the mass considered within the cosmic horizon. The possibility of changing the mass of the PBH as a result of accretion is analyzed.

  20. Hydrodynamic models for slurry bubble column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Gidaspow, D. [IIT Center, Chicago, IL (United States)

    1995-12-31

    The objective of this investigation is to convert a {open_quotes}learning gas-solid-liquid{close_quotes} fluidization model into a predictive design model. This model is capable of predicting local gas, liquid and solids hold-ups and the basic flow regimes: the uniform bubbling, the industrially practical churn-turbulent (bubble coalescence) and the slugging regimes. Current reactor models incorrectly assume that the gas and the particle hold-ups (volume fractions) are uniform in the reactor. They must be given in terms of empirical correlations determined under conditions that radically differ from reactor operation. In the proposed hydrodynamic approach these hold-ups are computed from separate phase momentum balances. Furthermore, the kinetic theory approach computes the high slurry viscosities from collisions of the catalyst particles. Thus particle rheology is not an input into the model.