WorldWideScience

Sample records for volume calibration techniques

  1. Novel gravimetric measurement technique for quantitative volume calibration in the sub-microliter range

    International Nuclear Information System (INIS)

    Liang, Dong; Zengerle, Roland; Steinert, Chris; Ernst, Andreas; Koltay, Peter; Bammesberger, Stefan; Tanguy, Laurent

    2013-01-01

    We present a novel measurement method based on the gravimetric principles adapted from the ASTM E542 and ISO 4787 standards for quantitative volume determination in the sub-microliter range. Such a method is particularly important for the calibration of non-contact micro dispensers as well as other microfluidic devices. The novel method is based on the linear regression analysis of continuously monitored gravimetric results and therefore is referred to as ‘gravimetric regression method (GRM)’. In this context, the regression analysis is necessary to compensate the mass loss due to evaporation that is significant for very small dispensing volumes. A full assessment of the measurement uncertainty of GRM is presented and results in a standard measurement uncertainty around 6 nl for dosage volumes in the range from 40 nl to 1 µl. The GRM has been experimentally benchmarked with a dual-dye ratiometric photometric method (Artel Inc., Westbrook, ME, USA), which can provide traceability of measurement to the International System of Units (SI) through reference standards maintained by NIST. Good precision (max. CV = 2.8%) and consistency (bias around 7 nl in the volume range from 40 to 400 nl) have been observed comparing the two methods. Based on the ASTM and ISO standards on the one hand and the benchmark with the photometric method on the other hand, two different approaches for establishing traceability for the GRM are discussed. (paper)

  2. Vibration transducer calibration techniques

    Science.gov (United States)

    Brinkley, D. J.

    1980-09-01

    Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.

  3. Fuel conditioning facility electrorefiner volume calibration

    International Nuclear Information System (INIS)

    Bucher, R.G.; Orechwa, Y.

    1995-01-01

    In one of the electrometallurgical process steps of the Fuel Conditioning Facility (FCF), die in-process nuclear material is dissolved in the electrorefiner tank in an upper layer of a mixture of liquid LiCl-KCl salt and a lower layer of liquid cadmium. The electrorefiner tank, as most process tanks, is not a smooth right-circular cylinder for which a single linear volume calibration curve could be fitted over the whole height of the tank. Rather, the tank contains many internal components, which cause systematic deviations from a single linear function. The nominal operating temperature of the electrorefiner is 500 degrees C although the salt and cadmium are introduced at 410 degrees C. The operating materials and temperatures preclude multiple calibration runs at operating conditions. In order to maximize the calibration information, multiple calibration runs were performed with water at room temperature. These data allow identification of calibration segments, and preliminary estimation of the calibration function and calibration uncertainties. The final calibration function is based on a combination of data from die water calibrations and the measurements made during the filling of the electrorefiner with salt and cadmium for operation

  4. Gravimetric gas determinations for volume calibration

    International Nuclear Information System (INIS)

    Gibbs, P.W.

    1991-01-01

    Gravimetric measurements of gases is one of the methods available for calibrating gas volumes. By inputting a known quantity of gas and measuring the resulting pressure and temperature, the system volume can be calculated using gas law principles. Historically, this method has been less accurate due to the difficulty in the mass determination. This difficulty comes from several sources. Two examples are the large tare weight of the gas container relative to the weight of gas and the external volume of the gas container relative to the standards. The application of a gravimetric gas determination to tank volume calibrations at the savannah River Site is discussed. Mass determinations on a 25,00 gram gas container were such that a 1500 gram quantity of gas was routinely determined to within ±0.2 gram at the 99% confidence level. In this paper the weighting design and the methods used to address the difficulties of the mass determination are detailed

  5. Computerized 50 liter volume calibration system

    International Nuclear Information System (INIS)

    Proffitt, T.H.

    1990-01-01

    A system has been designed for the Savannah River Site that will be used to calibrate product shipping containers. For accountability purposes, it is necessary that these containers be calibrated to a very high precision. The Computerized 50 Liter Volume Calibration System (CVCS), which is based on the Ideal Gas Law (IGL), will use reference volumes with precision of no less ±0.03%, and helium to calibrate the containers to have a total error of no greater than ±0.10%. A statistical interpretation of the system has given a theoretical total calculated error of ±0.08%. Tests with the system will be performed once fabrication is complete to experimentally verify the calculated error. Since the total error was calculated using the worst case scenario, the actual error should be significantly less than the calculated value. The computer controlled, totally automated system is traceable to the National Institute of Standards and Technology. The design, calibration procedure, and statistical interpretation of the system will be discussed. 1 ref

  6. Absolute calibration technique for spontaneous fission sources

    International Nuclear Information System (INIS)

    Zucker, M.S.; Karpf, E.

    1984-01-01

    An absolute calibration technique for a spontaneously fissioning nuclide (which involves no arbitrary parameters) allows unique determination of the detector efficiency for that nuclide, hence of the fission source strength

  7. Compact Optical Technique for Streak Camera Calibration

    International Nuclear Information System (INIS)

    Curt Allen; Terence Davies; Frans Janson; Ronald Justin; Bruce Marshall; Oliver Sweningsen; Perry Bell; Roger Griffith; Karla Hagans; Richard Lerche

    2004-01-01

    The National Ignition Facility is under construction at the Lawrence Livermore National Laboratory for the U.S. Department of Energy Stockpile Stewardship Program. Optical streak cameras are an integral part of the experimental diagnostics instrumentation. To accurately reduce data from the streak cameras a temporal calibration is required. This article describes a technique for generating trains of precisely timed short-duration optical pulses that are suitable for temporal calibrations

  8. Increased Automation in Stereo Camera Calibration Techniques

    Directory of Open Access Journals (Sweden)

    Brandi House

    2006-08-01

    Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.

  9. Solar Cell Calibration and Measurement Techniques

    Science.gov (United States)

    Bailey, Sheila; Brinker, Dave; Curtis, Henry; Jenkins, Phillip; Scheiman, Dave

    2004-01-01

    The increasing complexity of space solar cells and the increasing international markets for both cells and arrays has resulted in workshops jointly sponsored by NASDA, ESA and NASA. These workshops are designed to obtain international agreement on standardized values for the AMO spectrum and constant, recommend laboratory measurement practices and establish a set of protocols for international comparison of laboratory measurements. A working draft of an ISO standard, WD15387, "Requirements for Measurement and Calibration Procedures for Space Solar Cells" was discussed with a focus on the scope of the document, a definition of primary standard cell, and required error analysis for all measurement techniques. Working groups addressed the issues of Air Mass Zero (AMO) solar constant and spectrum, laboratory measurement techniques, and te international round robin methodology. A summary is presented of the current state of each area and the formulation of the ISO document.

  10. Compact Optical Technique for Streak Camera Calibration

    International Nuclear Information System (INIS)

    Bell, P; Griffith, R; Hagans, K; Lerche, R; Allen, C; Davies, T; Janson, F; Justin, R; Marshall, B; Sweningsen, O

    2004-01-01

    The National Ignition Facility (NIF) is under construction at the Lawrence Livermore National Laboratory (LLNL) for the U.S. Department of Energy Stockpile Stewardship Program. Optical streak cameras are an integral part of the experimental diagnostics instrumentation. To accurately reduce data from the streak cameras a temporal calibration is required. This article describes a technique for generating trains of precisely timed short-duration optical pulses1 (optical comb generators) that are suitable for temporal calibrations. These optical comb generators (Figure 1) are used with the LLNL optical streak cameras. They are small, portable light sources that produce a series of temporally short, uniformly spaced, optical pulses. Comb generators have been produced with 0.1, 0.5, 1, 3, 6, and 10-GHz pulse trains of 780-nm wavelength light with individual pulse durations of ∼25-ps FWHM. Signal output is via a fiber-optic connector. Signal is transported from comb generator to streak camera through multi-mode, graded-index optical fibers. At the NIF, ultra-fast streak-cameras are used by the Laser Fusion Program experimentalists to record fast transient optical signals. Their temporal resolution is unmatched by any other transient recorder. Their ability to spatially discriminate an image along the input slit allows them to function as a one-dimensional image recorder, time-resolved spectrometer, or multichannel transient recorder. Depending on the choice of photocathode, they can be made sensitive to photon energies from 1.1 eV to 30 keV and beyond. Comb generators perform two important functions for LLNL streak-camera users. First, comb generators are used as a precision time-mark generator for calibrating streak camera sweep rates. Accuracy is achieved by averaging many streak camera images of comb generator signals. Time-base calibrations with portable comb generators are easily done in both the calibration laboratory and in situ. Second, comb signals are applied

  11. ASD FieldSpec Calibration Setup and Techniques

    Science.gov (United States)

    Olive, Dan

    2001-01-01

    This paper describes the Analytical Spectral Devices (ASD) Fieldspec Calibration Setup and Techniques. The topics include: 1) ASD Fieldspec FR Spectroradiometer; 2) Components of Calibration; 3) Equipment list; 4) Spectral Setup; 5) Spectral Calibration; 6) Radiometric and Linearity Setup; 7) Radiometric setup; 8) Datadets Required; 9) Data files; and 10) Field of View Measurement. This paper is in viewgraph form.

  12. Another look at volume self-calibration: calibration and self-calibration within a pinhole model of Scheimpflug cameras

    International Nuclear Information System (INIS)

    Cornic, Philippe; Le Besnerais, Guy; Champagnat, Frédéric; Illoul, Cédric; Cheminet, Adam; Le Sant, Yves; Leclaire, Benjamin

    2016-01-01

    We address calibration and self-calibration of tomographic PIV experiments within a pinhole model of cameras. A complete and explicit pinhole model of a camera equipped with a 2-tilt angles Scheimpflug adapter is presented. It is then used in a calibration procedure based on a freely moving calibration plate. While the resulting calibrations are accurate enough for Tomo-PIV, we confirm, through a simple experiment, that they are not stable in time, and illustrate how the pinhole framework can be used to provide a quantitative evaluation of geometrical drifts in the setup. We propose an original self-calibration method based on global optimization of the extrinsic parameters of the pinhole model. These methods are successfully applied to the tomographic PIV of an air jet experiment. An unexpected by-product of our work is to show that volume self-calibration induces a change in the world frame coordinates. Provided the calibration drift is small, as generally observed in PIV, the bias on the estimated velocity field is negligible but the absolute location cannot be accurately recovered using standard calibration data. (paper)

  13. The KamLAND full-volume calibration system

    Energy Technology Data Exchange (ETDEWEB)

    Berger, B E [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Busenitz, J; Classen, T; Keefer, G; McKee, D; Piepke, A [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487 (United States); Decowski, M P; Elor, G; Frank, A; Freedman, S J; Fujikawa, B K; Galloway, M; Gray, F; Hsu, L; Ichimura, K; Kadel, R; Lendvai, C; O' Donnell, T [Physics Department, University of California, Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Dwyer, D A [W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Heeger, K M [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)] (and others)

    2009-04-15

    We have successfully built and operated a source deployment system for the KamLAND detector. This system was used to position radioactive sources throughout the delicate 1-kton liquid scintillator volume, while meeting stringent material cleanliness, material compatibility, and safety requirements. The calibration data obtained with this device were used to fully characterize detector position and energy reconstruction biases. As a result, the uncertainty in the size of the detector fiducial volume was reduced by a factor of two. Prior to calibration with this system, the fiducial volume was the largest source of systematic uncertainty in measuring the number of antineutrinos detected by KamLAND. This paper describes the design, operation and performance of this unique calibration system.

  14. The KamLAND Full-Volume Calibration System

    Energy Technology Data Exchange (ETDEWEB)

    KamLAND Collaboration; Berger, B. E.; Busenitz, J.; Classen, T.; Decowski, M. P.; Dwyer, D. A.; Elor, G.; Frank, A.; Freedman, S. J.; Fujikawa, B. K.; Galloway, M.; Gray, F.; Heeger, K. M.; Hsu, L.; Ichimura, K.; Kadel, R.; Keefer, G.; Lendvai, C.; McKee, D.; O' Donnell, T.; Piepke, A.; Steiner, H. M.; Syversrud, D.; Wallig, J.; Winslow, L. A.; Ebihara, T.; Enomoto, S.; Furuno, K.; Gando, Y.; Ikeda, H.; Inoue, K.; Kibe, Y.; Kishimoto, Y.; Koga, M.; Minekawa, Y.; Mitsui, T.; Nakajima, K.; Nakajima, K.; Nakamura, K.; Owada, K.; Shimizu, I.; Shimizu, Y.; Shirai, J.; Suekane, F.; Suzuki, A.; Tamae, K.; Yoshida, S.; Kozlov, A.; Murayama, H.; Grant, C.; Leonard, D. S.; Luk, K.-B.; Jillings, C.; Mauger, C.; McKeown, R. D.; Zhang, C.; Lane, C. E.; Maricic, J.; Miletic, T.; Batygov, M.; Learned, J. G.; Matsuno, S.; Pakvasa, S.; Foster, J.; Horton-Smith, G. A.; Tang, A.; Dazeley, S.; Downum, K. E.; Gratta, G.; Tolich, K.; Bugg, W.; Efremenko, Y.; Kamyshkov, Y.; Perevozchikov, O.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Piquemal, F.; Ricol, J.-S.

    2009-03-05

    We have successfully built and operated a source deployment system for the KamLAND detector. This system was used to position radioactive sources throughout the delicate 1-kton liquid scintillator volume, while meeting stringent material cleanliness, material compatibility, and safety requirements. The calibration data obtained with this device were used to fully characterize detector position and energy reconstruction biases. As a result, the uncertainty in the size of the detector fiducial volume was reduced by a factor of two. Prior to calibration with this system, the fiducial volume was the largest source of systematic uncertainty in measuring the number of antineutrinos detected by KamLAND. This paper describes the design, operation and performance of this unique calibration system.

  15. Improvement of the calibration technique of clinical dosemeters

    International Nuclear Information System (INIS)

    Ehlin Caldas, L.V.

    1988-08-01

    Clinical dosemeters constituted of ionization chambers connected to electrometers are usually calibrated as whole systems in appropriate radiation fields against secondary standard dosemeters in calibration laboratories. This work reports on a technique of component calibration procedures separately for chambers and electrometers applied in the calibration laboratory of IPEN-CNEN, Brazil. For electrometer calibration, redundancy was established by using a standard capacitor of 1000pF (General Radio, USA) and a standard current source based on air ionization with Sr 90 (PTW, Germany). The results from both methods applied to several electrometers of clinical dosemeters agreed within 0.4%. The calibration factors for the respective chambers were determined by intercomparing their response to the response of a certified calibrated chamber in a Co 60 calibration beam using a Keithley electrometer type 617. Overall calibration factors compared with the product of the respective component calibration factors for the tested dosemeters showed an agreement better than 0.7%. This deviation has to be considered with regard to an uncertainty of 2.5% in routine calibration of clinical dosemeters. Calibration by components permits to calibrate ionization chambers one at a time for those hospitals who have several ionization chambers but only one electrometer (small hospitals, hospitals in developing countries). 6 refs, 2 figs, 2 tabs

  16. Syringe calibration factors and volume correction factors for the NPL secondary standard radionuclide calibrator

    CERN Document Server

    Tyler, D K

    2002-01-01

    The activity assay of a radiopharmaceutical administration to a patient is normally achieved via the use of a radionuclide calibrator. Because of the different geometries and elemental compositions between plastic syringes and glass vials, the calibration factors for syringes may well be significantly different from those for the glass containers. The magnitude of these differences depends on the energies of the emitted photons. For some radionuclides variations have been observed of 70 %, it is therefore important to recalibrate for syringes or use syringe calibration factors. Calibration factors and volume correction factors have been derived for the NPL secondary standard radionuclide calibrator, for a variety of commonly used syringes and needles, for the most commonly used medical radionuclide.

  17. Compact optical technique for streak camera calibration

    International Nuclear Information System (INIS)

    Bell, Perry; Griffith, Roger; Hagans, Karla; Lerche, Richard; Allen, Curt; Davies, Terence; Janson, Frans; Justin, Ronald; Marshall, Bruce; Sweningsen, Oliver

    2004-01-01

    To produce accurate data from optical streak cameras requires accurate temporal calibration sources. We have reproduced an older technology for generating optical timing marks that had been lost due to component availability. Many improvements have been made which allow the modern units to service a much larger need. Optical calibrators are now available that produce optical pulse trains of 780 nm wavelength light at frequencies ranging from 0.1 to 10 GHz, with individual pulse widths of approximately 25 ps full width half maximum. Future plans include the development of single units that produce multiple frequencies to cover a wide temporal range, and that are fully controllable via an RS232 interface

  18. Compact optical technique for streak camera calibration

    Science.gov (United States)

    Bell, Perry; Griffith, Roger; Hagans, Karla; Lerche, Richard; Allen, Curt; Davies, Terence; Janson, Frans; Justin, Ronald; Marshall, Bruce; Sweningsen, Oliver

    2004-10-01

    To produce accurate data from optical streak cameras requires accurate temporal calibration sources. We have reproduced an older technology for generating optical timing marks that had been lost due to component availability. Many improvements have been made which allow the modern units to service a much larger need. Optical calibrators are now available that produce optical pulse trains of 780 nm wavelength light at frequencies ranging from 0.1 to 10 GHz, with individual pulse widths of approximately 25 ps full width half maximum. Future plans include the development of single units that produce multiple frequencies to cover a wide temporal range, and that are fully controllable via an RS232 interface.

  19. An Integrated Calibration Technique for Stereo Vision Systems (PREPRINT)

    Science.gov (United States)

    2010-03-01

    technique for stereo vision systems has been developed. To demonstrate and evaluate this calibration technique, multiple Wii Remotes (Wiimotes) from Nintendo ...from Nintendo were used to form stereo vision systems to perform 3D motion capture in real time. This integrated technique is a two-step process...Wiimotes) used in Nintendo Wii games. Many researchers have successfully dealt with the problem of camera calibration by taking images from a 2D

  20. Calibration

    International Nuclear Information System (INIS)

    Greacen, E.L.; Correll, R.L.; Cunningham, R.B.; Johns, G.G.; Nicolls, K.D.

    1981-01-01

    Procedures common to different methods of calibration of neutron moisture meters are outlined and laboratory and field calibration methods compared. Gross errors which arise from faulty calibration techniques are described. The count rate can be affected by the dry bulk density of the soil, the volumetric content of constitutional hydrogen and other chemical components of the soil and soil solution. Calibration is further complicated by the fact that the neutron meter responds more strongly to the soil properties close to the detector and source. The differences in slope of calibration curves for different soils can be as much as 40%

  1. Calibration technique for the neutron surface moisture measurement system

    International Nuclear Information System (INIS)

    Watson, W.T.; Shreve, D.C.

    1996-01-01

    A technique for calibrating the response of a surface neutron moisture measurement probe to material moisture concentration has been devised. Tests to ensure that the probe will function in the expected in-tank operating environment are also outlined

  2. A Method to Test Model Calibration Techniques: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, Ron; Polly, Ben; Neymark, Joel

    2016-09-01

    This paper describes a method for testing model calibration techniques. Calibration is commonly used in conjunction with energy retrofit audit models. An audit is conducted to gather information about the building needed to assemble an input file for a building energy modeling tool. A calibration technique is used to reconcile model predictions with utility data, and then the 'calibrated model' is used to predict energy savings from a variety of retrofit measures and combinations thereof. Current standards and guidelines such as BPI-2400 and ASHRAE-14 set criteria for 'goodness of fit' and assume that if the criteria are met, then the calibration technique is acceptable. While it is logical to use the actual performance data of the building to tune the model, it is not certain that a good fit will result in a model that better predicts post-retrofit energy savings. Therefore, the basic idea here is that the simulation program (intended for use with the calibration technique) is used to generate surrogate utility bill data and retrofit energy savings data against which the calibration technique can be tested. This provides three figures of merit for testing a calibration technique, 1) accuracy of the post-retrofit energy savings prediction, 2) closure on the 'true' input parameter values, and 3) goodness of fit to the utility bill data. The paper will also discuss the pros and cons of using this synthetic surrogate data approach versus trying to use real data sets of actual buildings.

  3. New method of assigning uncertainty in volume calibration

    International Nuclear Information System (INIS)

    Lechner, J.A.; Reeve, C.P.; Spiegelman, C.H.

    1980-12-01

    This paper presents a practical statistical overview of the pressure-volume calibration curve for large nuclear materials processing tanks. It explains the appropriateness of applying splines (piecewise polynomials) to this curve, and it presents an overview of the associated statistical uncertainties. In order to implement these procedures, a practical and portable FORTRAN IV program is provided along with its users' manual. Finally, the recommended procedure is demonstrated on actual tank data collected by NBS

  4. Calibration of a large volume argon-41 gas-effluent monitor

    International Nuclear Information System (INIS)

    Wilson, William E.; Lovas, Thomas A.

    1976-01-01

    In September of 1975, a large volume Argon-41 sampler was calibrated using a series connected calibration chamber of known sensitivity and a constant flow of activated Argon gas. The calibration included analysis of the effects of flow rate through the large volume sampler and yielded a calibration constant of 2.34 x 10 -8 μc/cm 3 /CPM. (author)

  5. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 2: Data standardization for tank calibration

    International Nuclear Information System (INIS)

    2007-01-01

    Measurements of the volume and height of liquid in a process accountancy tank are often made in order to estimate or verify the tank's calibration or volume measurement equation. The calibration equation relates the response of the tank's measurement system to some independent measure of tank volume. The ultimate purpose of the calibration exercise is to estimate the tank's volume measurement equation (the inverse of the calibration equation), which relates tank volume to measurement system response. In this part of ISO 18213, it is assumed that the primary measurement-system response variable is liquid height and that the primary measure of liquid content is volume. This part of ISO 18213 presents procedures for standardizing a set of calibration data to a fixed set of reference conditions so as to minimize the effect of variations in ambient conditions that occur during the measurement process. The procedures presented herein apply generally to measurements of liquid height and volume obtained for the purpose of calibrating a tank (i.e. calibrating a tank's measurement system). When used in connection with other parts of ISO 18213, these procedures apply specifically to tanks equipped with bubbler probe systems for measuring liquid content. The standardization algorithms presented herein can be profitably applied when only estimates of ambient conditions, such as temperature, are available. However, the most reliable results are obtained when relevant ambient conditions are measured for each measurement of volume and liquid height in a set of calibration data. Information is provided on scope, physical principles, data required, calibration data, dimensional changes in the tank, multiple calibration runs and results on standardized calibration data. Four annexes inform about density of water, buoyancy corrections for mass determination, determination of tank heel volume and statistical method for aligning data from several calibration runs. A bibliography is

  6. Calibration techniques and results for the Portsmouth Cf shuffler

    International Nuclear Information System (INIS)

    Gross, J.C.; Wines, K.M.

    1993-01-01

    As environmental concerns over radioactive waste disposal continue to rise, the importance of Californium shufflers as a versatile waste monitoring and segregation instrument also continue to increase. The extent to which different amounts and types of materials can be measured by the shuffler is directly related to the extent of its calibration. As shufflers become more common place and their waste management uses also rise, the importance of a wide ranging and thorough calibration becomes critical. This paper presents the techniques used at the Portsmouth Gaseous Diffusion Plant for calibrating the shuffler to detect levels of U-235 in radioactive waste. While the calibration techniques are similar to those used by Los Alamos, the standards that were used were constructed somewhat differently so that geometric effects are maximized. Also presented are shuffler transmission measurements that are used to determine the matrix type and the corresponding calibration. A discussion of the calibration data is given. This discussion includes specific aspects of the calibration such as overall range, high end limits, and poly shielding range and usefulness

  7. Improved beam-energy calibration technique for heavy ion accelerators

    International Nuclear Information System (INIS)

    Ferrero, A.M.J.; Garcia, A.; Gil, Salvador

    1989-01-01

    A simple technique for beam energy calibration of heavy-ion accelerators is presented. A thin hydrogenous target was bombarded with 12 C and 19 F, and the energies of the protons knocked out, elastically were measured at several angles using two detectors placed at equal angles on opposite sides of the beam. The use of these two detectors cancels the largest errors due to uncertainties in the angle and position at which the beam hits the target. An application of this energy calibration method to an electrostatic accelerator is described and the calibration constant of the analyzing magnet was obtained with an estimated error of 0.4 (Author) [es

  8. Calibration Technique of the Irradiated Thermocouple using Artificial Neural Network

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jin Tae; Joung, Chang Young; Ahn, Sung Ho; Yang, Tae Ho; Heo, Sung Ho; Jang, Seo Yoon [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    To correct the signals, the degradation rate of sensors needs to be analyzed, and re-calibration of sensors should be followed periodically. In particular, because thermocouples instrumented in the nuclear fuel rod are degraded owing to the high neutron fluence generated from the nuclear fuel, the periodic re-calibration process is necessary. However, despite the re-calibration of the thermocouple, the measurement error will be increased until next re-calibration. In this study, based on the periodically calibrated temperature - voltage data, an interpolation technique using the artificial neural network will be introduced to minimize the calibration error of the C-type thermocouple under the irradiation test. The test result shows that the calculated voltages derived from the interpolation function have good agreement with the experimental sampling data, and they also accurately interpolate the voltages at arbitrary temperature and neutron fluence. That is, once the reference data is obtained by experiments, it is possible to accurately calibrate the voltage signal at a certain neutron fluence and temperature using an artificial neural network.

  9. Alternative technique to neutron probe calibration in situ

    International Nuclear Information System (INIS)

    Encarnacao, F.; Carneiro, C.; Dall'Olio, A.

    1990-01-01

    An alternative technique of neutron probe calibration in situ was applied for Podzolic soil. Under field condition, the neutron probe calibration was performed using a special arrangement that prevented the lateral movement of water around the access tube of the neutron probe. During the experiments, successive amounts of water were uniformly infiltrated through the soil profile. Two plots were set to study the effect of the plot dimension on the slope of the calibration curve. The results obtained shown that the amounts of water transferred to the soil profile were significantly correlated to the integrals of count ratio along the soil profile on both plots. In consequence, the slope of calibration curve in field condition was determined. (author)

  10. Calibration and validation of full-field techniques

    Directory of Open Access Journals (Sweden)

    Thalmann R.

    2010-06-01

    Full Text Available We review basic metrological terms related to the use of measurement equipment for verification of numerical model calculations. We address three challenges that are faced when performing measurements in experimental mechanics with optical techniques: the calibration of a measuring instrument that (i measures strain values, (ii provides full-field data, and (iii is dynamic.

  11. SeaWiFS calibration and validation plan, volume 3

    International Nuclear Information System (INIS)

    Hooker, S.B.; Firestone, E.R.; Mcclain, C.R.; Esaias, W.E.; Barnes, W.; Guenther, B.; Endres, D.; Mitchell, B.G.; Barnes, R.

    1992-09-01

    The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) will be the first ocean-color satellite since the Nimbus-7 Coastal Zone Color Scanner (CZCS), which ceased operation in 1986. Unlike the CZCS, which was designed as a proof-of-concept experiment, SeaWiFS will provide routine global coverage every 2 days and is designed to provide estimates of photosynthetic concentrations of sufficient accuracy for use in quantitative studies of the ocean's primary productivity and biogeochemistry. A review of the CZCS mission is included that describes that data set's limitations and provides justification for a comprehensive SeaWiFS calibration and validation program. To accomplish the SeaWiFS scientific objectives, the sensor's calibration must be constantly monitored, and robust atmospheric corrections and bio-optical algorithms must be developed. The plan incorporates a multi-faceted approach to sensor calibration using a combination of vicarious (based on in situ observations) and onboard calibration techniques. Because of budget constraints and the limited availability of ship resources, the development of the operational algorithms (atmospheric and bio-optical) will rely heavily on collaborations with the Earth Observing System (EOS), the Moderate Resolution Imaging Spectrometer (MODIS) oceans team, and projects sponsored by other agencies, e.g., the U.S. Navy and the National Science Foundation (NSF). Other elements of the plan include the routine quality control of input ancillary data (e.g., surface wind, surface pressure, ozone concentration, etc.) used in the processing and verification of the level-0 (raw) data to level-1 (calibrated radiances), level-2 (derived products), and level-3 (gridded and averaged derived data) products

  12. Radiotracer techniques for measuring fluid flow and calibrating flow meters

    International Nuclear Information System (INIS)

    Cooper, E.L.

    1987-08-01

    Radiotracer techniques can be used to measure accurately both gas and liquid flow rates under operating conditions in a wide range of flow systems. They are ideally suited for calibrating flow meters as well as for measuring unmetered flows in industrial plants. Applications of these techniques range from measuring the flows of fuels and process fluids for energy and mass balance studies to measuring the flows of liquid and airborne effluents for pollution control. This report describes the various radiotracer techniques which can be used to measure fluid flows. The range of application and inherent accuracy of each technique is discussed

  13. Calibration of CR-39 for radon-related parameters using sealed cup technique

    International Nuclear Information System (INIS)

    Abo-Elmagd, M.; Daif, M. M.

    2010-01-01

    Effective radium content, mass and areal radon exhalation rates of soil and rock samples are important radon-related parameters and can be used as a better indicator of radon risk. A sealed cup fitted to a CR-39 detector and to the sample under measurement is an advantageous passive device for the measurement of these parameters. The main factors affecting the results are the detector calibration factor and the sample weight. The results of an active technique (Lucas cell) and the CR-39 detector have been found to be correlated resulting in a reliable detector calibration factor. The result illustrates the dependence of the CR-39 calibration factor with the sample weight which is difficult to use in practice, because each sample weight has its own calibration factor of CR-39. It is reported to demonstrate the advantage of a back diffusion correction. After correcting the results for back diffusion effects, one obtains an approximately constant calibration factor for the sample volumes up to one-third the total sealed cup volume. For this condition the calibration factor is equal to 0.237 track cm -2 per Bq m -3 d with about 1% uncertainty. (authors)

  14. Some problems of calibration technique in charged particle activation analysis

    International Nuclear Information System (INIS)

    Krasnov, N.N.; Zatolokin, B.V.; Konstantinov, I.O.

    1977-01-01

    It is shown that three different approaches to calibration technique based on the use of average cross-section, equivalent target thickness and thick target yield are adequate. Using the concept of thick target yield, a convenient charged particle activation equation is obtained. The possibility of simultaneous determination of two impurities, from which the same isotope is formed, is pointed out. The use of the concept of thick target yield facilitates the derivation of a simple formula for an absolute and comparative methods of analysis. The methodical error does not exceed 10%. Calibration technique and determination of expected sensitivity based on the thick target yield concept is also very convenient because experimental determination of thick target yield values is a much simpler procedure than getting activation curve or excitation function. (T.G.)

  15. SDSS-IV/MaNGA: SPECTROPHOTOMETRIC CALIBRATION TECHNIQUE

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Renbin; Sánchez-Gallego, José R. [Department of Physics and Astronomy, University of Kentucky, 505 Rose St., Lexington, KY 40506-0057 (United States); Tremonti, Christy; Bershady, Matthew A.; Eigenbrot, Arthur; Wake, David A. [Department of Astronomy, University of Winsconsin-Madison, 475 N. Charter Street, Madison, WI 53706-1582 (United States); Law, David R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Schlegel, David J. [Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8160 (United States); Bundy, Kevin [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Drory, Niv [McDonald Observatory, Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); MacDonald, Nicholas [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Bizyaev, Dmitry [Apache Point Observatory, P.O. Box 59, sunspot, NM 88349 (United States); Blanc, Guillermo A. [Departamento de Astronomía, Universidad de Chile, Camino el Observatorio 1515, Las Condes, Santiago (Chile); Blanton, Michael R.; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Cherinka, Brian [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Gunn, James E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Harding, Paul [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Sánchez, Sebastian F., E-mail: yanrenbin@uky.edu [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A.P. 70-264, 04510 Mexico D.F. (Mexico); and others

    2016-01-15

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV, is an integral-field spectroscopic survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2″ fibers to obtain resolved spectroscopy over a wide wavelength range of 3600–10300 Å. To map the internal variations within each galaxy, we need to perform accurate spectral surface photometry, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due to atmospheric throughput and the instrument response, but not for losses due to the finite geometry of the fiber aperture. This requires the use of standard star measurements to strictly separate these two flux loss factors (throughput versus geometry), a difficult challenge with standard single-fiber spectroscopy techniques due to various practical limitations. Therefore, we developed a technique for spectral surface photometry using multiple small fiber-bundles targeting standard stars simultaneously with galaxy observations. We discuss the principles of our approach and how they compare to previous efforts, and we demonstrate the precision and accuracy achieved. MaNGA's relative calibration between the wavelengths of Hα and Hβ has an rms of 1.7%, while that between [N ii] λ6583 and [O ii] λ3727 has an rms of 4.7%. Using extinction-corrected star formation rates and gas-phase metallicities as an illustration, this level of precision guarantees that flux calibration errors will be sub-dominant when estimating these quantities. The absolute calibration is better than 5% for more than 89% of MaNGA's wavelength range.

  16. SDSS-IV/MaNGA: SPECTROPHOTOMETRIC CALIBRATION TECHNIQUE

    International Nuclear Information System (INIS)

    Yan, Renbin; Sánchez-Gallego, José R.; Tremonti, Christy; Bershady, Matthew A.; Eigenbrot, Arthur; Wake, David A.; Law, David R.; Schlegel, David J.; Bundy, Kevin; Drory, Niv; MacDonald, Nicholas; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Hogg, David W.; Cherinka, Brian; Gunn, James E.; Harding, Paul; Sánchez, Sebastian F.

    2016-01-01

    Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV, is an integral-field spectroscopic survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2″ fibers to obtain resolved spectroscopy over a wide wavelength range of 3600–10300 Å. To map the internal variations within each galaxy, we need to perform accurate spectral surface photometry, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due to atmospheric throughput and the instrument response, but not for losses due to the finite geometry of the fiber aperture. This requires the use of standard star measurements to strictly separate these two flux loss factors (throughput versus geometry), a difficult challenge with standard single-fiber spectroscopy techniques due to various practical limitations. Therefore, we developed a technique for spectral surface photometry using multiple small fiber-bundles targeting standard stars simultaneously with galaxy observations. We discuss the principles of our approach and how they compare to previous efforts, and we demonstrate the precision and accuracy achieved. MaNGA's relative calibration between the wavelengths of Hα and Hβ has an rms of 1.7%, while that between [N ii] λ6583 and [O ii] λ3727 has an rms of 4.7%. Using extinction-corrected star formation rates and gas-phase metallicities as an illustration, this level of precision guarantees that flux calibration errors will be sub-dominant when estimating these quantities. The absolute calibration is better than 5% for more than 89% of MaNGA's wavelength range

  17. Technique for production of calibrated metal hydride films

    International Nuclear Information System (INIS)

    Langley, R.A.; Browning, J.F.; Balsley, S.D.; Banks, J.C.; Doyle, B.L.; Wampler, W.R.; Beavis, L.C.

    1999-01-01

    A technique has been developed for producing calibrated metal hydride films for use in the measurement of high-energy (5--15 MeV) particle reaction cross sections for hydrogen and helium isotopes on hydrogen isotopes. Absolute concentrations of various hydrogen isotopes in the film is expected to be determined to better than ±2% leading to the capacity of accurately measuring various reaction cross sections. Hydrogen isotope concentrations from near 100% to 5% can be made accurately and reproducibly. This is accomplished with the use of high accuracy pressure measurements coupled with high accuracy mass spectrometric measurements of each constituent partial pressure of the gas mixture during loading of the metal occluder films. Various techniques are used to verify the amount of metal present as well as the amount of hydrogen isotopes; high energy ion scattering analysis, PV measurements before, during and after loading, and thermal desorption/mass spectrometry measurements. The most appropriate metal to use for the occluder film appears to be titanium but other occluder metals are also being considered. Calibrated gas ratio samples, previously prepared, are used for the loading gas. Deviations from this calibrated gas ratio are measured using mass spectrometry during and after the loading process thereby determining the loading of the various hydrogen isotopes. These techniques are discussed and pertinent issues presented

  18. Drop size distribution measured by imaging: determination of the measurement volume by the calibration of the point spread function

    International Nuclear Information System (INIS)

    Fdida, Nicolas; Blaisot, Jean-Bernard

    2010-01-01

    Measurement of drop size distributions in a spray depends on the definition of the control volume for drop counting. For image-based techniques, this implies the definition of a depth-of-field (DOF) criterion. A sizing procedure based on an imaging model and associated with a calibration procedure is presented. Relations between image parameters and object properties are used to provide a measure of the size of the droplets, whatever the distance from the in-focus plane. A DOF criterion independent of the size of the drops and based on the determination of the width of the point spread function (PSF) is proposed. It allows to extend the measurement volume to defocused droplets and, due to the calibration of the PSF, to clearly define the depth of the measurement volume. Calibrated opaque discs, calibrated pinholes and an optical edge are used for this calibration. A comparison of the technique with a phase Doppler particle analyser and a laser diffraction granulometer is performed on an application to an industrial spray. Good agreement is found between the techniques when particular care is given to the sampling of droplets. The determination of the measurement volume is used to determine the drop concentration in the spray and the maximum drop concentration that imaging can support

  19. New calibration technique for KCD-based megavoltage imaging

    Science.gov (United States)

    Samant, Sanjiv S.; Zheng, Wei; DiBianca, Frank A.; Zeman, Herbert D.; Laughter, Joseph S.

    1999-05-01

    In megavoltage imaging, current commercial electronic portal imaging devices (EPIDs), despite having the advantage of immediate digital imaging over film, suffer from poor image contrast and spatial resolution. The feasibility of using a kinestatic charge detector (KCD) as an EPID to provide superior image contrast and spatial resolution for portal imaging has already been demonstrated in a previous paper. The KCD system had the additional advantage of requiring an extremely low dose per acquired image, allowing for superior imaging to be reconstructed form a single linac pulse per image pixel. The KCD based images utilized a dose of two orders of magnitude less that for EPIDs and film. Compared with the current commercial EPIDs and film, the prototype KCD system exhibited promising image qualities, despite being handicapped by the use of a relatively simple image calibration technique, and the performance limits of medical linacs on the maximum linac pulse frequency and energy flux per pulse delivered. This image calibration technique fixed relative image pixel values based on a linear interpolation of extrema provided by an air-water calibration, and accounted only for channel-to-channel variations. The counterpart of this for area detectors is the standard flat fielding method. A comprehensive calibration protocol has been developed. The new technique additionally corrects for geometric distortions due to variations in the scan velocity, and timing artifacts caused by mis-synchronization between the linear accelerator and the data acquisition system (DAS). The role of variations in energy flux (2 - 3%) on imaging is demonstrated to be not significant for the images considered. The methodology is presented, and the results are discussed for simulated images. It also allows for significant improvements in the signal-to- noise ratio (SNR) by increasing the dose using multiple images without having to increase the linac pulse frequency or energy flux per pulse. The

  20. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 1: Procedural overview

    International Nuclear Information System (INIS)

    2007-01-01

    Accurate determinations of volume are a fundamental component of any measurement-based system of control and accountability in a facility that processes or stores nuclear materials in liquid form. Volume determinations are typically made with the aid of a calibration or volume measurement equation that relates the response of the tank's measurement system to some independent measure of tank volume. The ultimate purpose of the calibration exercise is to estimate the tank's volume measurement equation (the inverse of the calibration equation), which relates tank volume to measurement system response. The steps carried out to acquire data for estimating the tank's calibration or volume measurement equation are collectively described as the process of tank calibration. This part of ISO 18213 describes procedures for tank calibration and volume determination for nuclear process tanks equipped with pressure-measurement systems for determining liquid content. Specifically, overall guidance is provided for planning a calibration exercise undertaken to obtain the data required for the measurement equation to estimate a tank's volume. The key steps in the procedure are also presented for subsequently using the estimated volume-measurement equation to determine tank liquid volumes. The procedures presented apply specifically to tanks equipped with bubbler probe systems for measuring liquid content. Moreover, these procedures produce reliable results only for clear (i.e. without suspended solids), homogeneous liquids that are at both thermal and static equilibrium. The paper elaborates on scope, physical principles involved, the calibration model, equipment required, a typical tank calibration procedure, calibration planning and pre-calibration activities, and volume determination. A bibliography is provided

  1. Respiration monitoring by Electrical Bioimpedance (EBI) Technique in a group of healthy males. Calibration equations

    International Nuclear Information System (INIS)

    Balleza, M; Vargas, M; Delgadillo, I; Kashina, S; Huerta, M R; Moreno, G

    2017-01-01

    Several research groups have proposed the electrical impedance tomography (EIT) in order to analyse lung ventilation. With the use of 16 electrodes, the EIT is capable to obtain a set of transversal section images of thorax. In previous works, we have obtained an alternating signal in terms of impedance corresponding to respiration from EIT images. Then, in order to transform those impedance changes into a measurable volume signal a set of calibration equations has been obtained. However, EIT technique is still expensive to attend outpatients in basics hospitals. For that reason, we propose the use of electrical bioimpedance (EBI) technique to monitor respiration behaviour. The aim of this study was to obtain a set of calibration equations to transform EBI impedance changes determined at 4 different frequencies into a measurable volume signal. In this study a group of 8 healthy males was assessed. From obtained results, a high mathematical adjustment in the group calibrations equations was evidenced. Then, the volume determinations obtained by EBI were compared with those obtained by our gold standard. Therefore, despite EBI does not provide a complete information about impedance vectors of lung compared with EIT, it is possible to monitor the respiration. (paper)

  2. Intra-shot MSE Calibration Technique For LHCD Experiments

    International Nuclear Information System (INIS)

    Ko, Jinseok; Scott, Steve; Shiraiwa, Syun'ichi; Greenwald, Martin; Parker, Ronald; Wallace, Gregory

    2009-01-01

    The spurious drift in pitch angle of order several degrees measured by the Motional Stark Effect (MSE) diagnostic in the Alcator C-Mod tokamak1 over the course of an experimental run day has precluded direct utilization of independent absolute calibrations. Recently, the underlying cause of the drift has been identified as thermal stress-induced birefringence in a set of in-vessel lenses. The shot-to-shot drift can be avoided by using MSE to measure only the change in pitch angle between a reference phase and a phase of physical interest within a single plasma discharge. This intra-shot calibration technique has been applied to the Lower Hybrid Current Drive (LHCD) experiments and the measured current profiles qualitatively demonstrate several predictions of LHCD theory such as an inverse dependence of current drive efficiency on the parallel refractive index and the presence of off-axis current drive.

  3. Self-calibration techniques of underwater gamma ray spectrometers.

    Science.gov (United States)

    Vlachos, D S

    2005-01-01

    In situ continuous monitoring of radioactivity in the water environment has many advantages compared to sampling and analysis techniques but a few shortcomings as well. Apart from the problems encountered in the assembly of the carrying autonomous systems, continuous operation some times alters the response function of the detectors. For example, the continuous operation of a photomultiplier tube results in a shift in the measured spectrum towards lower energies, making thus necessary the re-calibration of the detector. In this work, it is proved, that when measuring radioactivity in seawater, a photo peak around 50 keV will be always present in the measured spectrum. This peak is stable, depends only on the scattering rates of photons in seawater and, when it is detectable, can be used in conjunction with other peaks (40K and/or 208Tl) as a reference peak for the continuous calibration of the detector.

  4. Self-calibration techniques of underwater gamma ray spectrometers

    International Nuclear Information System (INIS)

    Vlachos, D.S.

    2005-01-01

    In situ continuous monitoring of radioactivity in the water environment has many advantages compared to sampling and analysis techniques but a few shortcomings as well. Apart from the problems encountered in the assembly of the carrying autonomous systems, continuous operation some times alters the response function of the detectors. For example, the continuous operation of a photomultiplier tube results in a shift in the measured spectrum towards lower energies, making thus necessary the re-calibration of the detector. In this work, it is proved, that when measuring radioactivity in seawater, a photo peak around 50 keV will be always present in the measured spectrum. This peak is stable, depends only on the scattering rates of photons in seawater and, when it is detectable, can be used in conjunction with other peaks ( 40 K and/or 208 Tl) as a reference peak for the continuous calibration of the detector

  5. 40 CFR 86.519-90 - Constant volume sampler calibration.

    Science.gov (United States)

    2010-07-01

    ... total calibration. Allow the system to stabilize for 3 minutes and repeat the data acquisition. (7) Data... decrease as reflected by lower values for M. Calibrations should be performed at pump startup and after...

  6. Radioactive source calibration technique for the CMS hadron calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, E.; Lawlor, C.; Rohlf, J.W. E-mail: rohlf@bu.edu; Wu, S.X.; Baumbaugh, A.; Elias, J.E.; Freeman, J.; Green, D.; Lazic, D.; Los, S.; Ronzhin, A.; Sergueev, S.; Shaw, T.; Vidal, R.; Whitmore, J.; Zimmerman, T.; Adams, M.; Burchesky, K.; Qian, W.; Baden, A.; Bard, R.; Breden, H.; Grassi, T.; Skuja, A.; Fisher, W.; Mans, J.; Tully, C.; Barnes, V.; Laasanen, A.; Barbaro, P. de; Budd, H

    2003-10-01

    Relative calibration of the scintillator tiles used in the hadronic calorimeter for the Compact Muon Solenoid detector at the CERN Large Hadron Collider is established and maintained using a radioactive source technique. A movable source can be positioned remotely to illuminate each scintillator tile individually, and the resulting photo-detector current is measured to provide the relative calibration. The unique measurement technique described here makes use of the normal high-speed data acquisition system required for signal digitization at the 40 MHz collider frequency. The data paths for collider measurements and source measurements are then identical, and systematic uncertainties associated with having different signal paths are avoided. In this high-speed mode, the source signal is observed as a Poisson photo-electron distribution with a mean that is smaller than the width of the electronics noise (pedestal) distribution. We report demonstration of the technique using prototype electronics for the complete readout chain and show the typical response observed with a 144 channel test beam system. The electronics noise has a root-mean-square of 1.6 least counts, and a 1 mCi source produces a shift of the mean value of 0.1 least counts. Because of the speed of the data acquisition system, this shift can be measured to a statistical precision better than a fraction of a percent on a millisecond time scale. The result is reproducible to better than 2% over a time scale of 1 month.

  7. Calibration and verification of surface contamination meters --- Procedures and techniques

    International Nuclear Information System (INIS)

    Schuler, C; Butterweck, G.; Wernli, C.; Bochud, F.; Valley, J.-F.

    2007-03-01

    A standardised measurement procedure for surface contamination meters (SCM) is presented. The procedure aims at rendering surface contamination measurements to be simply and safely interpretable. Essential for the approach is the introduction and common use of the radionuclide specific quantity 'guideline value' specified in the Swiss Radiation Protection Ordinance as unit for the measurement of surface activity. The according radionuclide specific 'guideline value count rate' can be summarized as verification reference value for a group of radionuclides ('basis guideline value count rate'). The concept can be generalized for SCM of the same type or for SCM of different types using he same principle of detection. A SCM multi source calibration technique is applied for the determination of the instrument efficiency. Four different electron radiation energy regions, four different photon radiation energy regions and an alpha radiation energy region are represented by a set of calibration sources built according to ISO standard 8769-2. A guideline value count rate representing the activity per unit area of a surface contamination of one guideline value can be calculated for any radionuclide using instrument efficiency, radionuclide decay data, contamination source efficiency, guideline value averaging area (100 cm 2 ), and radionuclide specific guideline value. n this way, instrument responses for the evaluation of surface contaminations are obtained for radionuclides without available calibration sources as well as for short-Iived radionuclides, for which the continuous replacement of certified calibration sources can lead to unreasonable costs. SCM verification is based on surface emission rates of reference sources with an active area of 100 cm 2 . The verification for a given list of radionuclides is based on the radionuclide specific quantity guideline value count rate. Guideline value count rates for groups of radionuclides can be represented within the maximum

  8. Mass Spectrometric Calibration of Controlled Fluoroform Leak Rate Devices Technique and Uncertainty Analysis

    CERN Document Server

    Balsley, S D; Laduca, C A

    2003-01-01

    Controlled leak rate devices of fluoroform on the order of 10 sup - sup 8 atm centre dot cc sec sup - sup 1 at 25 C are used to calibrate QC-1 War Reserve neutron tube exhaust stations for leak detection sensitivity. Close-out calibration of these tritium-contaminated devices is provided by the Gas Dynamics and Mass Spectrometry Laboratory, Organization 14406, which is a tritium analytical facility. The mass spectrometric technique used for the measurement is discussed, as is the first principals calculation (pressure, volume, temperature and time). The uncertainty of the measurement is largely driven by contributing factors in the determination of P, V and T. The expanded uncertainty of the leak rate measurement is shown to be 4.42%, with a coverage factor of 3 (k=3).

  9. An improved calibration technique for measurement of 41Ar activity in gaseous effluents

    International Nuclear Information System (INIS)

    Jose, M.T.; Raghunath, V.M.

    1992-01-01

    One of the methods used generally for the calibration of a gaseous effluent monitoring system is to estimate the efficiency of the detector system with a point source of 22 Na. The uncertainty in this method is the assumption that a point source kept at a distance from the detector and a volume source nearer the detector will have the same efficiency. To overcome this problem, a technique of using 22 Na in liquid form has been standardised. The uncertainties in the strength of the liquid source is avoided by proper intercomparison of the same with a reference standard traceable to a primary standard. The NaI system has been calibrated for estimating the 41 Ar activity from the peak area counts in the MCA and SCA systems respectively. (author). 1 ref., 1 tab

  10. Volume reduction techniques for solid radioactive wastes

    International Nuclear Information System (INIS)

    Clarke, J.H.

    1980-01-01

    This report gives an account of some of the techniques in current use in the UK for the treatment of solid radioactive wastes to reduce their volume prior to storage or disposal. Reference is also made to current research and development projects. It is based on a report presented at a recent International Atomic Energy Agency Technical Committee when this subject was the main theme. An IAEA Technical Series report covering techniques in use in all parts of the world should be published within the next two years. (author)

  11. State of the art: two-phase flow calibration techniques

    International Nuclear Information System (INIS)

    Stanley, M.L.

    1977-01-01

    The nuclear community faces a particularly difficult problem relating to the calibration of instrumentation in a two-phase flow steam/water environment. The rationale of the approach to water reactor safety questions in the United States demands that accurate measurements of mass flows in a decompressing two-phase flow be made. An accurate measurement dictates an accurate calibration. This paper addresses three questions relating to the state of the art in two-phase calibration: (1) What do we mean by calibration. (2) What is done now. (3) What should be done

  12. Left ventricular volume measurement in mice by conductance catheter: evaluation and optimization of calibration

    DEFF Research Database (Denmark)

    Nielsen, Jan Møller; Kristiansen, Steen B; Ringgaard, Steffen

    2007-01-01

    in mice (n = 52) with a Millar CC (SPR-839) and compared with MRI-derived volumes (V(MRI)). Significant correlations between V(CC) and V(MRI) [end-diastolic volume (EDV): R(2) = 0.85, P 2) = 0.88, P ... in the pulmonary artery was used to calibrate for parallel conductance and volume conversion was done by individual cylinder calibration. However, a significant underestimation was observed [EDV = -17.3 microl (-22.7 to -11.9 microl); ESV = -8.8 microl (-12.5 to -5.1 microl)]. Intravenous injection....... The dual-frequency method for estimation of parallel conductance failed to produce V(CC) that correlated with V(MRI). We conclude that selection of the calibration procedure for the CC has significant implications for the accuracy and precision of volume estimation and pressure-volume loop...

  13. Comparison of CT number calibration techniques for CBCT-based dose calculation

    International Nuclear Information System (INIS)

    Dunlop, Alex; McQuaid, Dualta; Nill, Simeon; Hansen, Vibeke N.; Oelfke, Uwe; Murray, Julia; Bhide, Shreerang; Harrington, Kevin; Poludniowski, Gavin; Nutting, Christopher; Newbold, Kate

    2015-01-01

    The aim of this work was to compare and validate various computed tomography (CT) number calibration techniques with respect to cone beam CT (CBCT) dose calculation accuracy. CBCT dose calculation accuracy was assessed for pelvic, lung, and head and neck (H and N) treatment sites for two approaches: (1) physics-based scatter correction methods (CBCT r ); (2) density override approaches including assigning water density to the entire CBCT (W), assignment of either water or bone density (WB), and assignment of either water or lung density (WL). Methods for CBCT density assignment within a commercially available treatment planning system (RS auto ), where CBCT voxels are binned into six density levels, were assessed and validated. Dose-difference maps and dose-volume statistics were used to compare the CBCT dose distributions with the ground truth of a planning CT acquired the same day as the CBCT. For pelvic cases, all CTN calibration methods resulted in average dose-volume deviations below 1.5 %. RS auto provided larger than average errors for pelvic treatments for patients with large amounts of adipose tissue. For H and N cases, all CTN calibration methods resulted in average dose-volume differences below 1.0 % with CBCT r (0.5 %) and RS auto (0.6 %) performing best. For lung cases, WL and RS auto methods generated dose distributions most similar to the ground truth. The RS auto density override approach is an attractive option for CTN adjustments for a variety of anatomical sites. RS auto methods were validated, resulting in dose calculations that were consistent with those calculated on diagnostic-quality CT images, for CBCT images acquired of the lung, for patients receiving pelvic RT in cases without excess adipose tissue, and for H and N cases. (orig.) [de

  14. Calibration and measurement of 210Pb using two independent techniques

    International Nuclear Information System (INIS)

    Villa, M.; Hurtado, S.; Manjon, G.; Garcia-Tenorio, R.

    2007-01-01

    An experimental procedure has been developed for a rapid and accurate determination of the activity concentration of 210 Pb in sediments by liquid scintillation counting (LSC). Additionally, an alternative technique using γ-spectrometry and Monte Carlo simulation has been developed. A radiochemical procedure, based on radium and barium sulphates co-precipitation have been applied to isolate the Pb-isotopes. 210 Pb activity measurements were done in a low background scintillation spectrometer Quantulus 1220. A calibration of the liquid scintillation spectrometer, including its α/β discrimination system, has been made, in order to minimize background and, additionally, some improvements are suggested for the calculation of the 210 Pb activity concentration, taking into account that 210 Pb counting efficiency cannot be accurately determined. Therefore, the use of an effective radiochemical yield, which can be empirically evaluated, is proposed. 210 Pb activity concentration in riverbed sediments from an area affected by NORM wastes has been determined using both the proposed method. Results using γ-spectrometry and LSC are compared to the results obtained following indirect α-spectrometry ( 210 Po) method

  15. Simple flight time calibration generator in PLL technique

    International Nuclear Information System (INIS)

    Lauch, J.

    1975-01-01

    Calibration and routine check-ups of flight time measuring systems can be carried out with the aid of defined flight time calibration spectra. This paper describes a simple flight time calibration generator capable of generating such calibration spectra in the form of line spectra or of a white spectrum. The flight time of the generator is adjustable in steps from 100 to 3,200 ns. The number of calibration lines can be set to 10 or to 20, resulting in line spacings ranging from 5 to 320 ns. The stop signals are generated by a crystal oscillator, the start signals are generated by a voltage-controlled oscillator locked in a phase control circuit. The start and stop rates can be adjusted in steps. (orig.) [de

  16. Thermoreflectance temperature imaging of integrated circuits: calibration technique and quantitative comparison with integrated sensors and simulations

    International Nuclear Information System (INIS)

    Tessier, G; Polignano, M-L; Pavageau, S; Filloy, C; Fournier, D; Cerutti, F; Mica, I

    2006-01-01

    Camera-based thermoreflectance microscopy is a unique tool for high spatial resolution thermal imaging of working integrated circuits. However, a calibration is necessary to obtain quantitative temperatures on the complex surface of integrated circuits. The spatial and temperature resolutions reached by thermoreflectance are excellent (360 nm and 2.5 x 10 -2 K in 1 min here), but the precision is more difficult to assess, notably due to the lack of comparable thermal techniques at submicron scales. We propose here a Peltier element control of the whole package temperature in order to obtain calibration coefficients simultaneously on several materials visible on the surface of the circuit. Under high magnifications, movements associated with thermal expansion are corrected using a piezo electric displacement and a software image shift. This calibration method has been validated by comparison with temperatures measured using integrated thermistors and diodes and by a finite volume simulation. We show that thermoreflectance measurements agree within a precision of ±2.3% with the on-chip sensors measurements. The diode temperature is found to underestimate the actual temperature of the active area by almost 70% due to the thermal contact of the diode with the substrate, acting as a heat sink

  17. Calibration technique for radiation measurements in vacuum ultraviolet - soft x-ray region

    International Nuclear Information System (INIS)

    Mizui, Jun-ichi

    1986-05-01

    This is a collection of the papers presented at the workshop on ''Calibration Technique for Radiation Measurements in Vacuum Ultraviolet - Soft X-ray Region'' held at the Institute of Plasma Physics, Nagoya University, on December 19 - 20, 1985, under the Collaborating Research Program at the Institute. The following topics were discussed at the workshop: the needs for the calibration of plasma diagnostic devices, present status of the calibration technique, use of the Synchrotron Orbit Radiations for radiometry, and others. (author)

  18. Calibration techniques for a fast duo-spectrometer

    International Nuclear Information System (INIS)

    Chapman, J.T.; Den Hartog, D.J.

    1996-06-01

    The authors have completed the upgrade and calibration of the Ion Dynamics Spectrometer (IDS), a high-speed Doppler duo-spectrometer which measures ion flow and temperature in the MST Reversed-field Pinch. This paper describes an in situ calibration of the diagnostic's phase and frequency response. A single clock was employed to generate both a digital test signal and a digitizer trigger thus avoiding frequency drift and providing a highly resolved measurement over the system bandwidth. Additionally, they review the measurement of the spectrometer instrument function and absolute intensity response. This calibration and subsequent performance demonstrate the IDS to be one of the fastest, highest throughput diagnostics of its kind. Typical measurements are presented

  19. Calibration of a solid state nuclear track detector for the measurements of volumic activity of Radon

    International Nuclear Information System (INIS)

    HAKAM, O.K.; LFERDE, M.; BERRADA, M.

    1994-01-01

    Time - integrated measurements of environmental radiation activity are commonly carried out using solid state nuclear track detectors ( SSNTD ). These detectors should be calibrated of volumic activity of radon. This paper reports the results of experiments conducted to calibrate cellulose nitrate films LR - 115 type II used for measurements of volumic activity of radon in indoor air in dwellings and enclosed work areas in Morocco. Calibration measurements were made in laboratory using a calibration chamber and a radon source. The calibration chamber is a cylindric box ( 2613,6 cm sup 3)which we have manufactured of aluminium. The radon source is a natural sample rich of aluminium (17,29 + 0 ,12) Bq/g. The films are placed in detector holder with membrane and exposed inside the calibration chamber to varying concentrations of radon. Following the exposure, the films were chemically etched in sodium hydroxide (2,5 N) at 60 C for 120 minutes. The number of registered alpha particle tracks were counted with an optical microscope. In the used etching conditions, the removed mean thickness is in the order of 6 micro m. Therefore, we have normalized the track density to this value . We obtained a calibration factor of 0, 58 tracks . cm sup -2/ K Bq . h . m sup -3 . 1 tab.; 1 fig.; 2 refs. (author)

  20. A calibration method for fringe reflection technique based on the analytical phase-slope description

    Science.gov (United States)

    Wu, Yuxiang; Yue, Huimin; Pan, Zhipeng; Liu, Yong

    2018-05-01

    The fringe reflection technique (FRT) has been one of the most popular methods to measure the shape of specular surface these years. The existing system calibration methods of FRT usually contain two parts, which are camera calibration and geometric calibration. In geometric calibration, the liquid crystal display (LCD) screen position calibration is one of the most difficult steps among all the calibration procedures, and its accuracy is affected by the factors such as the imaging aberration, the plane mirror flatness, and LCD screen pixel size accuracy. In this paper, based on the deduction of FRT analytical phase-slope description, we present a novel calibration method with no requirement to calibrate the position of LCD screen. On the other hand, the system can be arbitrarily arranged, and the imaging system can either be telecentric or non-telecentric. In our experiment of measuring the 5000mm radius sphere mirror, the proposed calibration method achieves 2.5 times smaller measurement error than the geometric calibration method. In the wafer surface measuring experiment, the measurement result with the proposed calibration method is closer to the interferometer result than the geometric calibration method.

  1. F-16D Pacer Calibration Techniques (SPEED PACER)

    Science.gov (United States)

    2012-07-01

    from the calibration FTTs and therefore, would add flight hours to accomplish. Other variables used in creation of the total costs are as follows: F-16... ZULU Time --- ∆ static source error correction n/d Δ Psic static pressure instrument error correction inHg Δ Ptic total pressure

  2. New Theoretical Analysis of the LRRM Calibration Technique for Vector Network Analyzers

    OpenAIRE

    Purroy Martín, Francesc; Pradell i Cara, Lluís

    2001-01-01

    In this paper, a new theoretical analysis of the four-standards line-reflect-reflect-match (LRRM) vector network-analyzer (VNA) calibration technique is presented. As a result, it is shown that the reference-impedance (to which the LRRM calibration is referred) cannot generally be defined whenever nonideal standards are used. Based on this consideration, a new algorithm to determine the on-wafer match standard is proposed that improves the LRRM calibration accuracy. Experimental verification ...

  3. A verified technique for calibrating space solar cells

    Science.gov (United States)

    Anspaugh, Bruce

    1987-01-01

    Solar cells have been flown on high-altitude balloons for over 24 years, to produce solar cell standards that can be used to set the intensity of solar simulators. The events of a typical balloon calibration flight are reported. These are: the preflight events, including the preflight cell measurements and the assembly of the flight cells onto the solar tracker; the activities at the National Scientific Balloon Facility in Palestine, Texas, including the preflight calibrations, the mating of the tracker and cells onto the balloon, preparations for launch, and the launch; the payload recovery, which includes tracking the balloon by aircraft, terminating the flight, and retrieving the payload. In 1985, the cells flow on the balloon were also flown on a shuttle flight and measured independently. The two measurement methods are compared and shown to agree within 1 percent.

  4. SU-E-T-470: Importance of HU-Mass Density Calibration Technique in Proton Pencil Beam Dose Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Penfold, S; Miller, A [University of Adelaide, Adelaide, SA (Australia)

    2015-06-15

    Purpose: Stoichiometric calibration of Hounsfield Units (HUs) for conversion to proton relative stopping powers (RStPs) is vital for accurate dose calculation in proton therapy. However proton dose distributions are not only dependent on RStP, but also on relative scattering power (RScP) of patient tissues. RScP is approximated from material density but a stoichiometric calibration of HU-density tables is commonly neglected. The purpose of this work was to quantify the difference in calculated dose of a commercial TPS when using HU-density tables based on tissue substitute materials and stoichiometric calibrated ICRU tissues. Methods: Two HU-density calibration tables were generated based on scans of the CIRS electron density phantom. The first table was based directly on measured HU and manufacturer quoted density of tissue substitute materials. The second was based on the same CT scan of the CIRS phantom followed by a stoichiometric calibration of ICRU44 tissue materials. The research version of Pinnacle{sup 3} proton therapy was used to compute dose in a patient CT data set utilizing both HU-density tables. Results: The two HU-density tables showed significant differences for bone tissues; the difference increasing with increasing HU. Differences in density calibration table translated to a difference in calculated RScP of −2.5% for ICRU skeletal muscle and 9.2% for ICRU femur. Dose-volume histogram analysis of a parallel opposed proton therapy prostate plan showed that the difference in calculated dose was negligible when using the two different HU-density calibration tables. Conclusion: The impact of HU-density calibration technique on proton therapy dose calculation was assessed. While differences were found in the calculated RScP of bony tissues, the difference in dose distribution for realistic treatment scenarios was found to be insignificant.

  5. Development of an in situ calibration technique for combustible gas detectors

    Science.gov (United States)

    Shumar, J. W.; Wynveen, R. A.; Lance, N., Jr.; Lantz, J. B.

    1977-01-01

    This paper describes the development of an in situ calibration procedure for combustible gas detectors (CGD). The CGD will be a necessary device for future space vehicles as many subsystems in the Environmental Control/Life Support System utilize or produce hydrogen (H2) gas. Existing calibration techniques are time-consuming and require support equipment such as an environmental chamber and calibration gas supply. The in situ calibration procedure involves utilization of a water vapor electrolysis cell for the automatic in situ generation of a H2/air calibration mixture within the flame arrestor of the CGD. The development effort concluded with the successful demonstration of in situ span calibrations of a CGD.

  6. An IQ mismatch calibration and compensation technique for wideband wireless transceivers

    International Nuclear Information System (INIS)

    Peng Jin; Zhou Liguo; Yao Heng; Yuan Fang; Shi Yin; Fang Zhi

    2014-01-01

    An IQ mismatch calibration and compensation technique based on the digital baseband for wideband wireless communication transmitters is proposed. The digital baseband transmits the signal used for IQ mismatch calibration. The signal passes through the RF transmitter path, the calibration loop (which is composed of a square power detector and a band-pass filter in the RF transceiver) and the variable gain amplifier of the receiver. The digital baseband samples the signal for IQ mismatch estimation and compensates for it. Compared with the self-calibration technique in the RF chip, the proposed technique saves area and power consumption for the wireless local area network solution. This technique has been successfully used for the 802.11n system and satisfies the requirement of the standard by achieving over 50 dB image suppression. (semiconductor integrated circuits)

  7. The development of an electrochemical technique for in situ calibrating of combustible gas detectors

    Science.gov (United States)

    Shumar, J. W.; Lantz, J. B.; Schubert, F. H.

    1976-01-01

    A program to determine the feasibility of performing in situ calibration of combustible gas detectors was successfully completed. Several possible techniques for performing the in situ calibration were proposed. The approach that showed the most promise involved the use of a miniature water vapor electrolysis cell for the generation of hydrogen within the flame arrestor of a combustible gas detector to be used for the purpose of calibrating the combustible gas detectors. A preliminary breadboard of the in situ calibration hardware was designed, fabricated and assembled. The breadboard equipment consisted of a commercially available combustible gas detector, modified to incorporate a water vapor electrolysis cell, and the instrumentation required for controlling the water vapor electrolysis and controlling and calibrating the combustible gas detector. The results showed that operation of the water vapor electrolysis at a given current density for a specific time period resulted in the attainment of a hydrogen concentration plateau within the flame arrestor of the combustible gas detector.

  8. Lunar imaging and ionospheric calibration for the Lunar Cherenkov technique

    NARCIS (Netherlands)

    McFadden, R.; Scholten, O.; Mevius, M.

    2013-01-01

    The Lunar Cherenkov technique is a promising method for UHE neutrino and cosmic ray detection which aims to detect nanosecond radio pulses produced during particle interactions in the Lunar regolith. For low frequency experiments, such as NuMoon, the frequency dependent dispersive effect of the

  9. Experimental device for obtaining calibration factor for the total count technique

    International Nuclear Information System (INIS)

    Gonçalves, Eduardo R.; Braz, Delson; Brandão, Luís Eduardo B.

    2017-01-01

    Nuclear technologies have widely used on industry plants in order to help to solve troubles processes/design or just obtain information of them. The Total Count technique for flow measurement has as main advantages: being an absolute technique, because it is independent of additional devices readings unless the directly used for recording the radioactive cloud, requiring only a single detector to provide the final result; the independence of the internal volume of the transport duct, can be applied in the presence or absence of obstructions; no restriction as to the nature of the product or material to be conveyed; it is a noninvasive technique which allows real-time diagnostics. To use Total Count Technique, knowledge of a geometric calibration factor is required. Called Factor F, it is obtained in the laboratory using an experimental apparatus to faithfully reproduce the geometry of the detection system and the pipeline that being analyzed and using the same radiotracer, therefore, its value is constant for each specific measuring system under survey. This experimental apparatus for obtaining the factor F consisting by a pipe of 2 ″PVC, which simulates a transmission line, where they were deposited 500 ml oil and the use of a specific pipette for use viscous fluids were added sequentially aliquots (50.00 ± 0.01) μl radiotracer (radionuclide photopeak energy of 198 Au 411.8 keV) and analyzing data obtained by three distinct detection systems composed of detectors NaI scintillators 1″ x 1 ″ and a data acquisition system. (author)

  10. Experimental device for obtaining calibration factor for the total count technique

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Eduardo R.; Braz, Delson [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Brandão, Luís Eduardo B. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Reatores

    2017-07-01

    Nuclear technologies have widely used on industry plants in order to help to solve troubles processes/design or just obtain information of them. The Total Count technique for flow measurement has as main advantages: being an absolute technique, because it is independent of additional devices readings unless the directly used for recording the radioactive cloud, requiring only a single detector to provide the final result; the independence of the internal volume of the transport duct, can be applied in the presence or absence of obstructions; no restriction as to the nature of the product or material to be conveyed; it is a noninvasive technique which allows real-time diagnostics. To use Total Count Technique, knowledge of a geometric calibration factor is required. Called Factor F, it is obtained in the laboratory using an experimental apparatus to faithfully reproduce the geometry of the detection system and the pipeline that being analyzed and using the same radiotracer, therefore, its value is constant for each specific measuring system under survey. This experimental apparatus for obtaining the factor F consisting by a pipe of 2 ″PVC, which simulates a transmission line, where they were deposited 500 ml oil and the use of a specific pipette for use viscous fluids were added sequentially aliquots (50.00 ± 0.01) μl radiotracer (radionuclide photopeak energy of 198 Au 411.8 keV) and analyzing data obtained by three distinct detection systems composed of detectors NaI scintillators 1″ x 1 ″ and a data acquisition system. (author)

  11. The peak efficiency calibration of volume source using 152Eu point source in computer

    International Nuclear Information System (INIS)

    Shen Tingyun; Qian Jianfu; Nan Qinliang; Zhou Yanguo

    1997-01-01

    The author describes the method of the peak efficiency calibration of volume source by means of 152 Eu point source for HPGe γ spectrometer. The peak efficiency can be computed by Monte Carlo simulation, after inputting parameter of detector. The computation results are in agreement with the experimental results with an error of +-3.8%, with an exception one is about +-7.4%

  12. Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera

    Science.gov (United States)

    Reyes, Bersain A.; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H.

    2016-01-01

    A smartphone-based tidal volume (VT) estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference VT measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE) of 14.998% ± 5.171% (mean ± SD) when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and VT to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS). Experiments were performed on twelve (N = 12) healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of −0.051 L and a RMSE of 0.189 ± 0.074 L corresponding to 18.559% ± 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis. PMID:26999152

  13. Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera

    Directory of Open Access Journals (Sweden)

    Bersain A. Reyes

    2016-03-01

    Full Text Available A smartphone-based tidal volume (VT estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference VT measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE of 14.998% ± 5.171% (mean ± SD when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and VT to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS. Experiments were performed on twelve (N = 12 healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of −0.051 L and a RMSE of 0.189 ± 0.074 L corresponding to 18.559% ± 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis.

  14. A robust and simple two-mode digital calibration technique for pipelined ADC

    Energy Technology Data Exchange (ETDEWEB)

    Yin Xiumei; Zhao Nan; Sekedi Bomeh Kobenge; Yang Huazhong, E-mail: yxm@mails.tsinghua.edu.cn [Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2011-03-15

    This paper presents a two-mode digital calibration technique for pipelined analog-to-digital converters (ADC). The proposed calibration eliminates the errors of residual difference voltage induced by capacitor mismatch of pseudorandom (PN) sequence injection capacitors at the ADC initialization, while applies digital background calibration to continuously compensate the interstage gain errors in ADC normal operation. The presented technique not only reduces the complexity of analog circuit by eliminating the implementation of PN sequence with accurate amplitude in analog domain, but also improves the performance of digital background calibration by minimizing the sensitivity of calibration accuracy to sub-ADC errors. The use of opamps with low DC gains in normal operation makes the proposed design more compatible with future nanometer CMOS technology. The prototype of a 12-bit 40-MS/s pipelined ADC with the two-mode digital calibration is implemented in 0.18-{mu}m CMOS process. Adopting a simple telescopic opamp with a DC gain of 58-dB in the first stage, the measured SFDR and SNDR within the first Nyquist zone reach 80-dB and 66-dB, respectively. With the calibration, the maximum integral nonlinearity (INL) of the ADC reduces from 4.75-LSB to 0.65-LSB, while the ADC core consumes 82-mW at 3.3-V power supply. (semiconductor integrated circuits)

  15. Evaluating Statistical Process Control (SPC) techniques and computing the uncertainty of force calibrations

    Science.gov (United States)

    Navard, Sharon E.

    1989-01-01

    In recent years there has been a push within NASA to use statistical techniques to improve the quality of production. Two areas where statistics are used are in establishing product and process quality control of flight hardware and in evaluating the uncertainty of calibration of instruments. The Flight Systems Quality Engineering branch is responsible for developing and assuring the quality of all flight hardware; the statistical process control methods employed are reviewed and evaluated. The Measurement Standards and Calibration Laboratory performs the calibration of all instruments used on-site at JSC as well as those used by all off-site contractors. These calibrations must be performed in such a way as to be traceable to national standards maintained by the National Institute of Standards and Technology, and they must meet a four-to-one ratio of the instrument specifications to calibrating standard uncertainty. In some instances this ratio is not met, and in these cases it is desirable to compute the exact uncertainty of the calibration and determine ways of reducing it. A particular example where this problem is encountered is with a machine which does automatic calibrations of force. The process of force calibration using the United Force Machine is described in detail. The sources of error are identified and quantified when possible. Suggestions for improvement are made.

  16. Volume calibration for nuclear materials control: ANSI N15.19-1989 and beyond

    International Nuclear Information System (INIS)

    Liebetrau, A.M.

    1994-03-01

    Since the last IAEA International Safeguards Symposium, a revised standard for volume calibration methodology was issued in the United States. Because the new standard reflects the advent of high-precision volume measurement technology, it is significantly different from the earlier standard which it supersedes. The new standard outlines a unified data standardization model that applies to process tanks equipped with differential pressure measurement systems for determining liquid content. At the heart of the model is an algorithm to determine liquid height from pressure measurements that accounts for the major factors affecting the accuracy of those measurements. The standardization model also contains algorithms that adjust data from volumetric and gravimetric provers to a standard set of reference conditions. A key component of the standardization model is an algorithm to take account of temperature-induced dimensional changes in the tank. Improved methods for the statistical treatment of calibration data have also appeared since the last Safeguards Symposium. A statistical method of alignment has been introduced that employs a least-squares criterion to determine ''optimal'' alignment factors. More importantly, a statistical model has been proposed that yields plausible estimates of the variance of height and volume measurements when significant run-to-run differences are present in the calibration data. The new standardization model and statistical methods described here are being implemented in a portable, user-friendly software program for use by IAEA inspectors and statisticians. Perhaps these methods will eventually find their way into appropriate international standards

  17. Calibration techniques and strategies for the present and future LHC electromagnetic calorimeters

    Science.gov (United States)

    Aleksa, M.

    2018-02-01

    This document describes the different calibration strategies and techniques applied by the two general purpose experiments at the LHC, ATLAS and CMS, and discusses them underlining their respective strengths and weaknesses from the view of the author. The resulting performances of both calorimeters are described and compared on the basis of selected physics results. Future upgrade plans for High Luminosity LHC (HL-LHC) are briefly introduced and planned calibration strategies for the upgraded detectors are shown.

  18. EASYTRAC Project: Work package 6.4 Reversal technique to calibrate gear and thread standards

    DEFF Research Database (Denmark)

    Carmignato, Simone; De Chiffre, Leonardo; Larsen, Erik

    This report was produced as a part of the project EASYTRAC, an EU project under the programme Competitive and Sustainable Growth: Contract No. G6RD-CT-2000-00188, coordinated by UNIMETRIK S.A. (Spain). The project is concerned with low uncertainty calibrations on coordinate measuring machines (CM...... (PTB) - Germany and Tampere University of Technology (TUT) - Finland. The present report describes feasibility and experimental results of a reversal and substitute element technique application for thread calibration on CMMs....

  19. Comparison of CT number calibration techniques for CBCT-based dose calculation

    Energy Technology Data Exchange (ETDEWEB)

    Dunlop, Alex [The Royal Marsden NHS Foundation Trust, Joint Department of Physics, Institute of Cancer Research, London (United Kingdom); The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom); McQuaid, Dualta; Nill, Simeon; Hansen, Vibeke N.; Oelfke, Uwe [The Royal Marsden NHS Foundation Trust, Joint Department of Physics, Institute of Cancer Research, London (United Kingdom); Murray, Julia; Bhide, Shreerang; Harrington, Kevin [The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom); The Institute of Cancer Research, London (United Kingdom); Poludniowski, Gavin [Karolinska University Hospital, Department of Medical Physics, Stockholm (Sweden); Nutting, Christopher [The Institute of Cancer Research, London (United Kingdom); Newbold, Kate [The Royal Marsden Hospital, Sutton, Surrey, Downs Road (United Kingdom)

    2015-12-15

    The aim of this work was to compare and validate various computed tomography (CT) number calibration techniques with respect to cone beam CT (CBCT) dose calculation accuracy. CBCT dose calculation accuracy was assessed for pelvic, lung, and head and neck (H and N) treatment sites for two approaches: (1) physics-based scatter correction methods (CBCT{sub r}); (2) density override approaches including assigning water density to the entire CBCT (W), assignment of either water or bone density (WB), and assignment of either water or lung density (WL). Methods for CBCT density assignment within a commercially available treatment planning system (RS{sub auto}), where CBCT voxels are binned into six density levels, were assessed and validated. Dose-difference maps and dose-volume statistics were used to compare the CBCT dose distributions with the ground truth of a planning CT acquired the same day as the CBCT. For pelvic cases, all CTN calibration methods resulted in average dose-volume deviations below 1.5 %. RS{sub auto} provided larger than average errors for pelvic treatments for patients with large amounts of adipose tissue. For H and N cases, all CTN calibration methods resulted in average dose-volume differences below 1.0 % with CBCT{sub r} (0.5 %) and RS{sub auto} (0.6 %) performing best. For lung cases, WL and RS{sub auto} methods generated dose distributions most similar to the ground truth. The RS{sub auto} density override approach is an attractive option for CTN adjustments for a variety of anatomical sites. RS{sub auto} methods were validated, resulting in dose calculations that were consistent with those calculated on diagnostic-quality CT images, for CBCT images acquired of the lung, for patients receiving pelvic RT in cases without excess adipose tissue, and for H and N cases. (orig.) [German] Ziel dieser Arbeit ist der Vergleich und die Validierung mehrerer CT-Kalibrierungsmethoden zur Dosisberechnung auf der Grundlage von Kegelstrahlcomputertomographie

  20. Development of self-calibration techniques for on-wafer and fixtured measurements: a novel approach

    OpenAIRE

    Pradell i Cara, Lluís; Purroy Martín, Francesc; Cáceres, M.

    1992-01-01

    Network Analyzer self-calibration techniques - TRL, LMR, TAR- are developed, implemented and compared in several transmission media. A novel LMR (Line-Match-Reflect) technique based on known LINE and REFLECT Standards, is proposed and compared to conventional LMR (based on known LINE and MATCH Standards) and other techniques (TRL, TAR). They are applied to on-wafer S-parameter measurement as well as to coaxial, waveguide and microstrip media. Experimental results up to 40 GHz are presented. ...

  1. Volume corrections factors in the measurement of 99mTc and 123I activities in radionuclide calibrators

    International Nuclear Information System (INIS)

    Correia, Amanda Ribeiro; Rezende, Eduarda Alexandre; Iwahara, Akira; Oliveira, Antonio Eduardo de; Oliveira, Estela Maria de; Tauhata, Luiz; Chaves, Taina Olivieri

    2012-01-01

    To determine correction factors for the variation in volume of radiopharmaceuticals in containers of different geometries, comparing the influence of such factors on the determination of 99m Tc and 123 I activity with two types of calibrators - one with ionization chamber and another with Geiger-Mueller (G-M) detector -; and to evaluate calibrators performance in the measurement of 99m Tc and 1 '2 3 I activities. Materials and Methods: Eight calibrators, 10R glass vials, 3 and 5 mL plastic syringes and 99m Tc and 123 I solutions were utilized. The correction factors were determined with basis on practical measurements of the variation in the calibrators' response according to the volume of radionuclide solution in the glass vials. The performance was evaluated according to the acceptance criterion of +- 10% accuracy required by the Brazilian standard. Results: The variation of the calibrators' response according to the variation in radionuclide volume was reasonably greater in the calibrator with G-M detector. It was also greater for 123 I than for 99m Tc. Conclusion: The results confirm that the calibrators' response depends on the radionuclide volume contained in the vials. Such dependence is more critical for the calibrators equipped with G-M detector and for 123 I as compared with 99m Tc. (author)

  2. Sandia software guidelines: Volume 5, Tools, techniques, and methodologies

    Energy Technology Data Exchange (ETDEWEB)

    1989-07-01

    This volume is one in a series of Sandia Software Guidelines intended for use in producing quality software within Sandia National Laboratories. This volume describes software tools and methodologies available to Sandia personnel for the development of software, and outlines techniques that have proven useful within the Laboratories and elsewhere. References and evaluations by Sandia personnel are included. 6 figs.

  3. Improvement in QEPAS system utilizing a second harmonic based wavelength calibration technique

    Science.gov (United States)

    Zhang, Qinduan; Chang, Jun; Wang, Fupeng; Wang, Zongliang; Xie, Yulei; Gong, Weihua

    2018-05-01

    A simple laser wavelength calibration technique, based on second harmonic signal, is demonstrated in this paper to improve the performance of quartz enhanced photoacoustic spectroscopy (QEPAS) gas sensing system, e.g. improving the signal to noise ratio (SNR), detection limit and long-term stability. Constant current, corresponding to the gas absorption line, combining f/2 frequency sinusoidal signal are used to drive the laser (constant driving mode), a software based real-time wavelength calibration technique is developed to eliminate the wavelength drift due to ambient fluctuations. Compared to conventional wavelength modulation spectroscopy (WMS), this method allows lower filtering bandwidth and averaging algorithm applied to QEPAS system, improving SNR and detection limit. In addition, the real-time wavelength calibration technique guarantees the laser output is modulated steadily at gas absorption line. Water vapor is chosen as an objective gas to evaluate its performance compared to constant driving mode and conventional WMS system. The water vapor sensor was designed insensitive to the incoherent external acoustic noise by the numerical averaging technique. As a result, the SNR increases 12.87 times in wavelength calibration technique based system compared to conventional WMS system. The new system achieved a better linear response (R2 = 0 . 9995) in concentration range from 300 to 2000 ppmv, and achieved a minimum detection limit (MDL) of 630 ppbv.

  4. Assessment of MODIS On-Orbit Calibration Using a Deep Convective Cloud Technique

    Science.gov (United States)

    Mu, Qiaozhen; Wu, Aisheng; Chang, Tiejun; Angal, Amit; Link, Daniel; Xiong, Xiaoxiong; Doelling, David R.; Bhatt, Rajendra

    2016-01-01

    The MODerate Resolution Imaging Spectroradiometer (MODIS) sensors onboard Terra and Aqua satellites are calibrated on-orbit with a solar diffuser (SD) for the reflective solar bands (RSB). The MODIS sensors are operating beyond their designed lifetime and hence present a major challenge to maintain the calibration accuracy. The degradation of the onboard SD is tracked by a solar diffuser stability monitor (SDSM) over a wavelength range from 0.41 to 0.94 micrometers. Therefore, any degradation of the SD beyond 0.94 micrometers cannot be captured by the SDSM. The uncharacterized degradation at wavelengths beyond this limit could adversely affect the Level 1B (L1B) product. To reduce the calibration uncertainties caused by the SD degradation, invariant Earth-scene targets are used to monitor and calibrate the MODIS L1B product. The use of deep convective clouds (DCCs) is one such method and particularly significant for the short-wave infrared (SWIR) bands in assessing their long-term calibration stability. In this study, we use the DCC technique to assess the performance of the Terra and Aqua MODIS Collection-6 L1B for RSB 1 3- 7, and 26, with spectral coverage from 0.47 to 2.13 micrometers. Results show relatively stable trends in Terra and Aqua MODIS reflectance for most bands. Careful attention needs to be paid to Aqua band 1, Terra bands 3 and 26 as their trends are larger than 1% during the study time period. We check the feasibility of using the DCC technique to assess the stability in MODIS bands 17-19. The assessment test on response versus scan angle (RVS) calibration shows substantial trend difference for Aqua band 1between different angles of incidence (AOIs). The DCC technique can be used to improve the RVS calibration in the future.

  5. Comparison of process estimation techniques for on-line calibration monitoring

    International Nuclear Information System (INIS)

    Shumaker, B. D.; Hashemian, H. M.; Morton, G. W.

    2006-01-01

    The goal of on-line calibration monitoring is to reduce the number of unnecessary calibrations performed each refueling cycle on pressure, level, and flow transmitters in nuclear power plants. The effort requires a baseline for determining calibration drift and thereby the need for a calibration. There are two ways to establish the baseline: averaging and modeling. Averaging techniques have proven to be highly successful in the applications when there are a large number of redundant transmitters; but, for systems with little or no redundancy, averaging methods are not always reliable. That is, for non-redundant transmitters, more sophisticated process estimation techniques are needed to augment or replace the averaging techniques. This paper explores three well-known process estimation techniques; namely Independent Component Analysis (ICA), Auto-Associative Neural Networks (AANN), and Auto-Associative Kernel Regression (AAKR). Using experience and data from an operating nuclear plant, the paper will present an evaluation of the effectiveness of these methods in detecting transmitter drift in actual plant conditions. (authors)

  6. Investigation of ground-based microwave radiometer calibration techniques at 530 hPa

    Directory of Open Access Journals (Sweden)

    G. Maschwitz

    2013-10-01

    Full Text Available Ground-based microwave radiometers (MWR are becoming more and more common for remotely sensing the atmospheric temperature and humidity profile as well as path-integrated cloud liquid water content. The calibration accuracy of the state-of-the-art MWR HATPRO-G2 (Humidity And Temperature Profiler – Generation 2 was investigated during the second phase of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II in northern Chile (5320 m above mean sea level, 530 hPa conducted by the Atmospheric Radiation Measurement (ARM program conducted between August and October 2009. This study assesses the quality of the two frequently used liquid nitrogen and tipping curve calibrations by performing a detailed error propagation study, which exploits the unique atmospheric conditions of RHUBC-II. Both methods are known to have open issues concerning systematic offsets and calibration repeatability. For the tipping curve calibration an uncertainty of ±0.1 to ±0.2 K (K-band and ±0.6 to ±0.7 K (V-band is found. The uncertainty in the tipping curve calibration is mainly due to atmospheric inhomogeneities and the assumed air mass correction for the Earth curvature. For the liquid nitrogen calibration the estimated uncertainty of ±0.3 to ±1.6 K is dominated by the uncertainty of the reflectivity of the liquid nitrogen target. A direct comparison between the two calibration techniques shows that for six of the nine channels that can be calibrated with both methods, they agree within the assessed uncertainties. For the other three channels the unexplained discrepancy is below 0.5 K. Systematic offsets, which may cause the disagreement of both methods within their estimated uncertainties, are discussed.

  7. Better Drumming Through Calibration: Techniques for Pre-Performance Robotic Percussion Optimization

    OpenAIRE

    Murphy, Jim; Kapur, Ajay; Carnegie, Dale

    2012-01-01

    A problem with many contemporary musical robotic percussion systems lies in the fact that solenoids fail to respond lin-early to linear increases in input velocity. This nonlinearity forces performers to individually tailor their compositions to specific robotic drummers. To address this problem, we introduce a method of pre-performance calibration using metaheuristic search techniques. A variety of such techniques are introduced and evaluated and the results of the optimized solenoid-based p...

  8. Manual calibration of liquid scintillation counter using the channel ratio technique

    International Nuclear Information System (INIS)

    Moussa, H.M.; Townsend, L.; Miller, L.F.

    1999-01-01

    The objectives of this activity are to introduce students to liquid scintillation counting and to calibrate the counter using the sample channel ratio technique. This is accomplished by using quenched standards set for 14 C and tritium ( 3 H) to generate a quench correction curve for the scintillation solution. It is a good method for students to gain a detailed understanding of issues important to manual calibration of a liquid scintillation counter, and results can be compared with a built-in automatic method

  9. Standardization of Laser Methods and Techniques for Vibration Measurements and Calibrations

    International Nuclear Information System (INIS)

    Martens, Hans-Juergen von

    2010-01-01

    The realization and dissemination of the SI units of motion quantities (vibration and shock) have been based on laser interferometer methods specified in international documentary standards. New and refined laser methods and techniques developed by national metrology institutes and by leading manufacturers in the past two decades have been swiftly specified as standard methods for inclusion into in the series ISO 16063 of international documentary standards. A survey of ISO Standards for the calibration of vibration and shock transducers demonstrates the extended ranges and improved accuracy (measurement uncertainty) of laser methods and techniques for vibration and shock measurements and calibrations. The first standard for the calibration of laser vibrometers by laser interferometry or by a reference accelerometer calibrated by laser interferometry (ISO 16063-41) is on the stage of a Draft International Standard (DIS) and may be issued by the end of 2010. The standard methods with refined techniques proved to achieve wider measurement ranges and smaller measurement uncertainties than that specified in the ISO Standards. The applicability of different standardized interferometer methods to vibrations at high frequencies was recently demonstrated up to 347 kHz (acceleration amplitudes up to 350 km/s 2 ). The relative deviations between the amplitude measurement results of the different interferometer methods that were applied simultaneously, differed by less than 1% in all cases.

  10. Current calibration, treatment, and treatment planning techniques among institutions participating in the Children's Oncology Group

    International Nuclear Information System (INIS)

    Urie, Marcia; FitzGerald, T.J.; Followill, David; Laurie, Fran; Marcus, Robert; Michalski, Jeff

    2003-01-01

    Purpose: To report current technology implementation, radiation therapy physics and treatment planning practices, and results of treatment planning exercises among 261 institutions belonging to the Children's Oncology Group (COG). Methods and Materials: The Radiation Therapy Committee of the newly formed COG mandated that each institution demonstrate basic physics and treatment planning abilities by satisfactorily completing a questionnaire and four treatment planning exercises designed by the Quality Assurance Review Center. The planning cases are (1) a maxillary sinus target volume (for two-dimensional planning), (2) a Hodgkin's disease mantle field (for irregular-field and off-axis dose calculations), (3) a central axis blocked case, and (4) a craniospinal irradiation case. The questionnaire and treatment plans were submitted (as of 1/30/02) by 243 institutions and completed satisfactorily by 233. Data from this questionnaire and analyses of the treatment plans with monitor unit calculations are presented. Results: Of the 243 clinics responding, 54% use multileaf collimators routinely, 94% use asymmetric jaws routinely, and 13% use dynamic wedges. Nearly all institutions calibrate their linear accelerators following American Association of Physicists in Medicine protocols, currently 16% with TG-51 and 81% with TG-21 protocol. Treatment planning systems are relied on very heavily for all calculations, including monitor units. Techniques and results of each of the treatment planning exercises are presented. Conclusions: Together, these data provide a unique compilation of current (2001) radiation therapy practices in institutions treating pediatric patients. Overall, the COG facilities have the equipment and the personnel to perform high-quality radiation therapy. With ongoing quality assurance review, radiation therapy compliance with COG protocols should be high

  11. Quantitative CT: technique dependence of volume estimation on pulmonary nodules

    Science.gov (United States)

    Chen, Baiyu; Barnhart, Huiman; Richard, Samuel; Colsher, James; Amurao, Maxwell; Samei, Ehsan

    2012-03-01

    Current estimation of lung nodule size typically relies on uni- or bi-dimensional techniques. While new three-dimensional volume estimation techniques using MDCT have improved size estimation of nodules with irregular shapes, the effect of acquisition and reconstruction parameters on accuracy (bias) and precision (variance) of the new techniques has not been fully investigated. To characterize the volume estimation performance dependence on these parameters, an anthropomorphic chest phantom containing synthetic nodules was scanned and reconstructed with protocols across various acquisition and reconstruction parameters. Nodule volumes were estimated by a clinical lung analysis software package, LungVCAR. Precision and accuracy of the volume assessment were calculated across the nodules and compared between protocols via a generalized estimating equation analysis. Results showed that the precision and accuracy of nodule volume quantifications were dependent on slice thickness, with different dependences for different nodule characteristics. Other parameters including kVp, pitch, and reconstruction kernel had lower impact. Determining these technique dependences enables better volume quantification via protocol optimization and highlights the importance of consistent imaging parameters in sequential examinations.

  12. 2D-3D Registration of CT Vertebra Volume to Fluoroscopy Projection: A Calibration Model Assessment

    Directory of Open Access Journals (Sweden)

    P. Bifulco

    2010-01-01

    Full Text Available This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1 mm for displacements parallel to the fluoroscopic plane, and of order of 10 mm for the orthogonal displacement.

  13. A Study on the Guided Wave Mode Conversion using Self-calibrating Technique

    International Nuclear Information System (INIS)

    Park, Jung Chul; Cho, Youn Ho

    2000-01-01

    The guided wave mode conversion phenomena were investigated for the NDE of a plate-like structure with thickness variation. The ratios of reflection and transmission (R/T) were measured via the self-calibrating procedure which allows us to obtain experimental guided wave data in a more reliable way regardless of the coupling uncertainty between transducer and specimen. The results on R/T could be used to determine the thickness reduction of the structure. It was shown that not only the incident modes but also the converted ones need to be considered in the self-calibrating guided wave inspection to extract a reasonable correlation between experimental data and the thickness variation. Through this study, the potential of guided wave inspection as a quantitative NDE technique was explored based on the combined concept of self-calibration and multi-mode conversion in guided wave scattering problems

  14. A robust calibration technique for acoustic emission systems based on momentum transfer from a ball drop

    Science.gov (United States)

    McLaskey, Gregory C.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M.

    2015-01-01

    We describe a technique to estimate the seismic moment of acoustic emissions and other extremely small seismic events. Unlike previous calibration techniques, it does not require modeling of the wave propagation, sensor response, or signal conditioning. Rather, this technique calibrates the recording system as a whole and uses a ball impact as a reference source or empirical Green’s function. To correctly apply this technique, we develop mathematical expressions that link the seismic moment $M_{0}$ of internal seismic sources (i.e., earthquakes and acoustic emissions) to the impulse, or change in momentum $\\Delta p $, of externally applied seismic sources (i.e., meteor impacts or, in this case, ball impact). We find that, at low frequencies, moment and impulse are linked by a constant, which we call the force‐moment‐rate scale factor $C_{F\\dot{M}} = M_{0}/\\Delta p$. This constant is equal to twice the speed of sound in the material from which the seismic sources were generated. Next, we demonstrate the calibration technique on two different experimental rock mechanics facilities. The first example is a saw‐cut cylindrical granite sample that is loaded in a triaxial apparatus at 40 MPa confining pressure. The second example is a 2 m long fault cut in a granite sample and deformed in a large biaxial apparatus at lower stress levels. Using the empirical calibration technique, we are able to determine absolute source parameters including the seismic moment, corner frequency, stress drop, and radiated energy of these magnitude −2.5 to −7 seismic events.

  15. Feasibility of the use of optimisation techniques to calibrate the models used in a post-closure radiological assessment

    International Nuclear Information System (INIS)

    Laundy, R.S.

    1991-01-01

    This report addresses the feasibility of the use of optimisation techniques to calibrate the models developed for the impact assessment of a radioactive waste repository. The maximum likelihood method for improving parameter estimates is considered in detail, and non-linear optimisation techniques for finding solutions are reviewed. Applications are described for the calibration of groundwater flow, radionuclide transport and biosphere models. (author)

  16. Novel Calibration Technique for a Coulometric Evolved Vapor Analyzer for Measuring Water Content of Materials

    Science.gov (United States)

    Bell, S. A.; Miao, P.; Carroll, P. A.

    2018-04-01

    Evolved vapor coulometry is a measurement technique that selectively detects water and is used to measure water content of materials. The basis of the measurement is the quantitative electrolysis of evaporated water entrained in a carrier gas stream. Although this measurement has a fundamental principle—based on Faraday's law which directly relates electrolysis current to amount of substance electrolyzed—in practice it requires calibration. Commonly, reference materials of known water content are used, but the variety of these is limited, and they are not always available for suitable values, materials, with SI traceability, or with well-characterized uncertainty. In this paper, we report development of an alternative calibration approach using as a reference the water content of humid gas of defined dew point traceable to the SI via national humidity standards. The increased information available through this new type of calibration reveals a variation of the instrument performance across its range not visible using the conventional approach. The significance of this is discussed along with details of the calibration technique, example results, and an uncertainty evaluation.

  17. A Technique Using Calibrated Photography and Photoshop for Accurate Shade Analysis and Communication.

    Science.gov (United States)

    McLaren, Edward A; Figueira, Johan; Goldstein, Ronald E

    2017-02-01

    This article reviews the critical aspects of controlling the shade-taking environment and discusses various modalities introduced throughout the years to acquire and communicate shade information. Demonstrating a highly calibrated digital photographic technique for capturing shade information, this article shows how to use Photoshop® to standardize images and extract color information from the tooth and shade tab for use by a ceramist for an accurate shade-matching restoration.

  18. NLT and extrapolated DLT:3-D cinematography alternatives for enlarging the volume of calibration.

    Science.gov (United States)

    Hinrichs, R N; McLean, S P

    1995-10-01

    This study investigated the accuracy of the direct linear transformation (DLT) and non-linear transformation (NLT) methods of 3-D cinematography/videography. A comparison of standard DLT, extrapolated DLT, and NLT calibrations showed the standard (non-extrapolated) DLT to be the most accurate, especially when a large number of control points (40-60) were used. The NLT was more accurate than the extrapolated DLT when the level of extrapolation exceeded 100%. The results indicated that when possible one should use the DLT with a control object, sufficiently large as to encompass the entire activity being studied. However, in situations where the activity volume exceeds the size of one's DLT control object, the NLT method should be considered.

  19. Calibration of Ge(Li) semiconductor detector by method using agar volume source

    International Nuclear Information System (INIS)

    Yanase, Nobuyuki; Kasai, Atsushi

    1979-12-01

    The Ge(Li) semiconductor detector was calibrated for measurements of environmental samples. The radioisotopes used for standard sources are 22 Na, 51 Cr, 56 Co, 57 Co, 133 Ba, 137 Cs, 144 Ce and 241 Am. These are mixed with hot agar aqueous solution and fixed uniformly in a cylindrical plastic case in cooling. The agar volume source is advantageous in handling over the fluid aqueous source. The prepared cylindrical standard sources are in diameters 6 and 8 cm and thicknesses 1, 5, 10, 20, 30 and 40 mm (only for 8 cm diameter). The radioactivities of prepared standard sources are between 0.03 μCi and 0.2 μCi. It takes only a week to make the calibration except data processing. The obtained full energy peak efficiency curves include 5 - 10% error due to preparation of agar source, reference radioactivity data of purchased standard solutions, reference data of branching ratio of gamma-ray and sum effect. The efficiency curves, however, are sufficient for quantitative analysis of environmental samples. (author)

  20. Aseptic minimum volume vitrification technique for porcine parthenogenetically activated blastocyst.

    Science.gov (United States)

    Lin, Lin; Yu, Yutao; Zhang, Xiuqing; Yang, Huanming; Bolund, Lars; Callesen, Henrik; Vajta, Gábor

    2011-01-01

    Minimum volume vitrification may provide extremely high cooling and warming rates if the sample and the surrounding medium contacts directly with the respective liquid nitrogen and warming medium. However, this direct contact may result in microbial contamination. In this work, an earlier aseptic technique was applied for minimum volume vitrification. After equilibration, samples were loaded on a plastic film, immersed rapidly into factory derived, filter-sterilized liquid nitrogen, and sealed into sterile, pre-cooled straws. At warming, the straw was cut, the filmstrip was immersed into a 39 degree C warming medium, and the sample was stepwise rehydrated. Cryosurvival rates of porcine blastocysts produced by parthenogenetical activation did not differ from control, vitrified blastocysts with Cryotop. This approach can be used for minimum volume vitrification methods and may be suitable to overcome the biological dangers and legal restrictions that hamper the application of open vitrification techniques.

  1. Evaluation of a laser scanner for large volume coordinate metrology: a comparison of results before and after factory calibration

    International Nuclear Information System (INIS)

    Ferrucci, M; Muralikrishnan, B; Sawyer, D; Phillips, S; Petrov, P; Yakovlev, Y; Astrelin, A; Milligan, S; Palmateer, J

    2014-01-01

    Large volume laser scanners are increasingly being used for a variety of dimensional metrology applications. Methods to evaluate the performance of these scanners are still under development and there are currently no documentary standards available. This paper describes the results of extensive ranging and volumetric performance tests conducted on a large volume laser scanner. The results demonstrated small but clear systematic errors that are explained in the context of a geometric error model for the instrument. The instrument was subsequently returned to the manufacturer for factory calibration. The ranging and volumetric tests were performed again and the results are compared against those obtained prior to the factory calibration. (paper)

  2. On-line Monitoring and Calibration Techniques in Nuclear Power Plants

    International Nuclear Information System (INIS)

    Hashemian, H.M.

    2011-01-01

    Years of research, testing and experience in the field of sensor diagnostics have yielded many technologies which offer financial as well as operational benefits to the nuclear industry. Among these technologies are On-Line Monitoring (OLM) and On-Line Calibration of critical process monitoring sensors such as resistance temperature detectors (RTD), thermocouples, and pressure transmitters to name a few. The remote access and verification of these sensors have been shown to limit the exposure of maintenance personnel to harsh environments while at the same time effectively and efficiently diagnosing the health and performance of these sensors. In addition to sensors, technologies exist in determining not only the health of instrumentation and control (I and C) cabling that carries the signals from these sensors, but also these same cable testing techniques can be used in the remote evaluation of many end devices used in safety related operations as well. Given these advances in sensor system monitoring techniques it would seem to follow that nuclear utilities from around the world would be applying these tried and true techniques to optimize up time and to provide additional confidence in the output of processing sensors. However, although several of the world's regulatory bodies have approved of the concept of these techniques, few utilities have undertaken to fully embrace on-line monitoring and on-line calibration of nuclear process sensors. In the United States efforts are now underway, with representatives of the U.S. nuclear industry and nuclear power plant vendors to obtain generic NRC licensing for the use of OLM in nuclear power plants. If approved, generic licensing will help pave the way toward greater implementation of OLM and its related calibration techniques. (author)

  3. Gamma ray densitometry techniques for measuring of volume fractions

    Energy Technology Data Exchange (ETDEWEB)

    Affonso, Renato Raoni Werneck; Silva, Ademir Xavier da; Salgado, Cesar Marques, E-mail: raoniwa@yahoo.com.br, E-mail: ademir@nuclear.ufrj.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Knowledge of the volume fraction in a multiphase flow is of key importance in predicting the performance of many systems and processes. It is therefore an important parameter to characterize such flows. In the context of nuclear techniques, the gamma ray densitometry is promising and this is due to its non-invasive characteristics and very reliable results. It is used in several applications for multiphase flows (water-oil-air), which are employed tools such as: computational fluid dynamics, artificial neural networks and statistical methods of radiation transport, such as the Monte Carlo method. Based on the gamma radiation techniques for measurements of volume fractions, the aim of this paper is to present several techniques developed for this purpose. (author)

  4. Gamma ray densitometry techniques for measuring of volume fractions

    International Nuclear Information System (INIS)

    Affonso, Renato Raoni Werneck; Silva, Ademir Xavier da; Salgado, Cesar Marques

    2015-01-01

    Knowledge of the volume fraction in a multiphase flow is of key importance in predicting the performance of many systems and processes. It is therefore an important parameter to characterize such flows. In the context of nuclear techniques, the gamma ray densitometry is promising and this is due to its non-invasive characteristics and very reliable results. It is used in several applications for multiphase flows (water-oil-air), which are employed tools such as: computational fluid dynamics, artificial neural networks and statistical methods of radiation transport, such as the Monte Carlo method. Based on the gamma radiation techniques for measurements of volume fractions, the aim of this paper is to present several techniques developed for this purpose. (author)

  5. Calibration techniques for the hot wire anemometer in a low velocity region

    International Nuclear Information System (INIS)

    Fujimura, Kaoru; Kawamura, Hiroshi

    1980-03-01

    In connection with experiments on coolant flow in the core of multi-purpose VHTR, a low-velocity calibration wind tunnel was made, and techniques for the hot wire anemometer in the air were investigated. Following are the results. 1) A technique using the frequency of von Karman vortex street is not recommended because of the irregular mode in a low velocity region. 2) A Pitot tube is valid only for the flow velocities larger than 1 m/s. 3) The thermal trace technique is suitable in a relatively wide range of velocity, if velocity defect in the wake is compensated for. When flow velocity is larger than 1 m/s, the thermal trace technique is consistent with the Pitot tube method. (author)

  6. A Novel Digital Background Calibration Technique for 16 bit SHA-less Multibit Pipelined ADC

    Directory of Open Access Journals (Sweden)

    Swina Narula

    2016-01-01

    Full Text Available In this paper, a high resolution of 16 bit and high speed of 125MS/s, multibit Pipelined ADC with digital background calibration is presented. In order to achieve low power, SHA-less front end is used with multibit stages. The first and second stages are used here as a 3.5 bit and the stages from third to seventh are of 2.5 bit and last stage is of 3-bit flash ADC. After bit alignment and truncation of total 19 bits, 16 bits are used as final digital output. To precise the remove linear gain error of the residue amplifier and capacitor mismatching error, a digital background calibration technique is used, which is a combination of signal dependent dithering (SDD and butterfly shuffler. To improve settling time of residue amplifier, a special circuit of voltage separation is used. With the proposed digital background calibration technique, the spurious-free dynamic range (SFDR has been improved to 97.74 dB @30 MHz and 88.9 dB @150 MHz, and the signal-to-noise and distortion ratio (SNDR has been improved to 79.77 dB @ 30 MHz, and 73.5 dB @ 150 MHz. The implementation of the Pipelined ADC has been completed with technology parameters of 0.18μm CMOS process with 1.8 V supply. Total power consumption is 300 mW by the proposed ADC.

  7. Calibration techniques for the in vivo measurement of alpha-emitting actinides

    International Nuclear Information System (INIS)

    Fleming, R.R.

    1976-01-01

    Reliable interpretation of in vivo measurements for alpha-emitting actinides deposited in the lungs is largely dependent on three factors: correction of observed count rates for background contributions; correction for photon absorption in the body; and accurate calibration of the counting system. Terrestrial and cosmic radiation contributions can be minimized by extensive shielding and good pulse-shape discrimination. Techniques are available to minimize errors inherent in the calibration of an in vivo counting system. Minimum amounts of alpha-emitting actinides detectable in the lungs are primarily affected by the accuracy of two factors: predicted body background due to 137 Cs and 40 K, and estimated photon absorption in chest-wall tissue. A matched pair of 12.5-cm-dia phoswich detectors, purchased from the Harshaw Chemical Company, are used to measure low-energy photons emitted by the radioactive actinides

  8. Volume reduction of ion exchange resin by a pyrolysis technique

    International Nuclear Information System (INIS)

    Matsuda, M.; Funabashi, K.; Uchida, S.; Kikuchi, M.

    1985-01-01

    Volume reduction techniques, such as incineration and acid digestion, of spent ion exchange resins from nuclear power plants are being developed with a view toward reducing radioactive waste volume and also making the final waste form more stable. The authors chose pyrolysis as a technique that can be done at low operating temperatures and low gas flow rates in a reactor vessel. Fundamental experiments were performed to clarify the resin pyrolysis characteristics, and the optimum pyrolysis temperature was determined. Consequently, a pilot plant with a treatment capacity of approx. 50 kg/batch was constructed based on the results. Using the pilot plant, the authors are now performing pyrolysis of the resins and solidification of their residues. This report will give the results of fundamental experiments and pilot plant tests

  9. Utilization of advanced calibration techniques in stochastic rock fall analysis of quarry slopes

    Science.gov (United States)

    Preh, Alexander; Ahmadabadi, Morteza; Kolenprat, Bernd

    2016-04-01

    In order to study rock fall dynamics, a research project was conducted by the Vienna University of Technology and the Austrian Central Labour Inspectorate (Federal Ministry of Labour, Social Affairs and Consumer Protection). A part of this project included 277 full-scale drop tests at three different quarries in Austria and recording key parameters of the rock fall trajectories. The tests involved a total of 277 boulders ranging from 0.18 to 1.8 m in diameter and from 0.009 to 8.1 Mg in mass. The geology of these sites included strong rock belonging to igneous, metamorphic and volcanic types. In this paper the results of the tests are used for calibration and validation a new stochastic computer model. It is demonstrated that the error of the model (i.e. the difference between observed and simulated results) has a lognormal distribution. Selecting two parameters, advanced calibration techniques including Markov Chain Monte Carlo Technique, Maximum Likelihood and Root Mean Square Error (RMSE) are utilized to minimize the error. Validation of the model based on the cross validation technique reveals that in general, reasonable stochastic approximations of the rock fall trajectories are obtained in all dimensions, including runout, bounce heights and velocities. The approximations are compared to the measured data in terms of median, 95% and maximum values. The results of the comparisons indicate that approximate first-order predictions, using a single set of input parameters, are possible and can be used to aid practical hazard and risk assessment.

  10. New technology and techniques for x-ray mirror calibration at PANTER

    Science.gov (United States)

    Freyberg, Michael J.; Budau, Bernd; Burkert, Wolfgang; Friedrich, Peter; Hartner, Gisela; Misaki, Kazutami; Mühlegger, Martin

    2008-07-01

    The PANTER X-ray Test Facility has been utilized successfully for developing and calibrating X-ray astronomical instrumentation for observatories such as ROSAT, Chandra, XMM-Newton, Swift, etc. Future missions like eROSITA, SIMBOL-X, or XEUS require improved spatial resolution and broader energy band pass, both for optics and for cameras. Calibration campaigns at PANTER have made use of flight spare instrumentation for space applications; here we report on a new dedicated CCD camera for on-ground calibration, called TRoPIC. As the CCD is similar to ones used for eROSITA (pn-type, back-illuminated, 75 μm pixel size, frame store mode, 450 μm micron wafer thickness, etc.) it can serve as prototype for eROSITA camera development. New techniques enable and enhance the analysis of measurements of eROSITA shells or silicon pore optics. Specifically, we show how sub-pixel resolution can be utilized to improve spatial resolution and subsequently the characterization of of mirror shell quality and of point spread function parameters in particular, also relevant for position reconstruction of astronomical sources in orbit.

  11. Immersed transient eddy current flow metering: a calibration-free velocity measurement technique for liquid metals

    Science.gov (United States)

    Krauter, N.; Stefani, F.

    2017-10-01

    Eddy current flow meters are widely used for measuring the flow velocity of electrically conducting fluids. Since the flow induced perturbations of a magnetic field depend both on the geometry and the conductivity of the fluid, extensive calibration is needed to get accurate results. Transient eddy current flow metering has been developed to overcome this problem. It relies on tracking the position of an impressed eddy current system that is moving with the same velocity as the conductive fluid. We present an immersed version of this measurement technique and demonstrate its viability by numerical simulations and a first experimental validation.

  12. Software development with two port calibration techniques for RHIC impedance measurements

    International Nuclear Information System (INIS)

    Mane, V.; Shea, T.

    1993-01-01

    The coupling impedance of accelerator devices is measured by simulating the beam with a central wire and measuring the scattering parameters of the system. The wire pipe system forms a mismatch with the 50 ohm transmission line. An integrated software environment has been developed in LabVIEW, for the Macintosh. The program measures the scattering parameters of some known standards, determines the connect scattering parameters of a device using TRL calibration technique and gives the impedance of the device. Its performance has been tested for some known microwave devices

  13. Illumination technique for the relative calibration of the ASTRI SST-2M camera

    International Nuclear Information System (INIS)

    Rodeghiero, Gabriele; Catalano, Osvaldo; Segreto, Alberto; De Caprio, Vincenzo; Giro, Enrico; Lessio, Luigi; Conconi, Paolo; Canestrari, Rodolfo

    2014-01-01

    We present a new illumination technique for the camera relative gain calibration of the ASTRI SST-2M Cherenkov telescope. The camera illumination is achieved by means of an optical fiber that diffuses the light inside a protective PMMA window above the focal plane. We report the encouraging results of the development tests carried out on two PMMA window prototypes illuminated by a standard optical fiber. We checked also the reliability of the method by a series of ray tracing simulations for different scattering models and PMMA window shapes finding good agreement with experimental results

  14. Illumination technique for the relative calibration of the ASTRI SST-2M camera

    Energy Technology Data Exchange (ETDEWEB)

    Rodeghiero, Gabriele, E-mail: gabriele.rodeghiero@studenti.unipd.it [Department of Physics and Astronomy, University of Padova, Vicolo dell' Osservatorio 5, 35100 PD (Italy); Catalano, Osvaldo; Segreto, Alberto [INAF IASF Palermo, Via Ugo La Malfa 153, 90146 PA (Italy); De Caprio, Vincenzo [INAF OACN, Salita Moiariello, 16, 80131 Napoli, NA (Italy); Giro, Enrico; Lessio, Luigi [INAF OAPD, Vicolo dell' Osservatorio 5, 35100 PD (Italy); Conconi, Paolo; Canestrari, Rodolfo [INAF OAB, Via E. Bianchi 46, 23807 Merate, LC (Italy)

    2014-11-11

    We present a new illumination technique for the camera relative gain calibration of the ASTRI SST-2M Cherenkov telescope. The camera illumination is achieved by means of an optical fiber that diffuses the light inside a protective PMMA window above the focal plane. We report the encouraging results of the development tests carried out on two PMMA window prototypes illuminated by a standard optical fiber. We checked also the reliability of the method by a series of ray tracing simulations for different scattering models and PMMA window shapes finding good agreement with experimental results.

  15. Immersed transient eddy current flow metering: a calibration-free velocity measurement technique for liquid metals

    International Nuclear Information System (INIS)

    Krauter, N; Stefani, F

    2017-01-01

    Eddy current flow meters are widely used for measuring the flow velocity of electrically conducting fluids. Since the flow induced perturbations of a magnetic field depend both on the geometry and the conductivity of the fluid, extensive calibration is needed to get accurate results. Transient eddy current flow metering has been developed to overcome this problem. It relies on tracking the position of an impressed eddy current system that is moving with the same velocity as the conductive fluid. We present an immersed version of this measurement technique and demonstrate its viability by numerical simulations and a first experimental validation. (paper)

  16. Grid Generation Techniques Utilizing the Volume Grid Manipulator

    Science.gov (United States)

    Alter, Stephen J.

    1998-01-01

    This paper presents grid generation techniques available in the Volume Grid Manipulation (VGM) code. The VGM code is designed to manipulate existing line, surface and volume grids to improve the quality of the data. It embodies an easy to read rich language of commands that enables such alterations as topology changes, grid adaption and smoothing. Additionally, the VGM code can be used to construct simplified straight lines, splines, and conic sections which are common curves used in the generation and manipulation of points, lines, surfaces and volumes (i.e., grid data). These simple geometric curves are essential in the construction of domain discretizations for computational fluid dynamic simulations. By comparison to previously established methods of generating these curves interactively, the VGM code provides control of slope continuity and grid point-to-point stretchings as well as quick changes in the controlling parameters. The VGM code offers the capability to couple the generation of these geometries with an extensive manipulation methodology in a scripting language. The scripting language allows parametric studies of a vehicle geometry to be efficiently performed to evaluate favorable trends in the design process. As examples of the powerful capabilities of the VGM code, a wake flow field domain will be appended to an existing X33 Venturestar volume grid; negative volumes resulting from grid expansions to enable flow field capture on a simple geometry, will be corrected; and geometrical changes to a vehicle component of the X33 Venturestar will be shown.

  17. Quantitative comparison of two independent lateral force calibration techniques for the atomic force microscope

    International Nuclear Information System (INIS)

    Barkley, Sarice S.; Cannara, Rachel J.; Deng Zhao; Gates, Richard S.; Reitsma, Mark G.

    2012-01-01

    Two independent lateral-force calibration methods for the atomic force microscope (AFM)--the hammerhead (HH) technique and the diamagnetic lateral force calibrator (D-LFC)--are systematically compared and found to agree to within 5% or less, but with precision limited to about 15%, using four different tee-shaped HH reference probes. The limitations of each method, both of which offer independent yet feasible paths toward traceable accuracy, are discussed and investigated. We find that stiff cantilevers may produce inconsistent D-LFC values through the application of excessively high normal loads. In addition, D-LFC results vary when the method is implemented using different modes of AFM feedback control, constant height and constant force modes, where the latter is more consistent with the HH method and closer to typical experimental conditions. Specifically, for the D-LFC apparatus used here, calibration in constant height mode introduced errors up to 14 %. In constant force mode using a relatively stiff cantilever, we observed an ≅ 4 % systematic error per μN of applied load for loads ≤ 1 μN. The issue of excessive load typically emerges for cantilevers whose flexural spring constant is large compared with the normal spring constant of the D-LFC setup (such that relatively small cantilever flexural displacements produce relatively large loads). Overall, the HH method carries a larger uncertainty, which is dominated by uncertainty in measurement of the flexural spring constant of the HH cantilever as well as in the effective length dimension of the cantilever probe. The D-LFC method relies on fewer parameters and thus has fewer uncertainties associated with it. We thus show that it is the preferred method of the two, as long as care is taken to perform the calibration in constant force mode with low applied loads.

  18. Research and development of treatment techniques for LLW from decommissioning: Decontamination and volume reduction techniques

    International Nuclear Information System (INIS)

    Hirabayashi, T.; Kameo, Y.; Nakashio, N.

    2001-01-01

    For the purpose of reducing the amount and/or volume of low-level radioactive waste (LLW) arising from decommissioning of nuclear reactor, the Japan Atomic Energy Research Institute (JAERI) has been developing four decontamination techniques. They are: (a) Gas-carrying abrasive method, (b) In-situ remote electropolishing method for pipe system before dismantling, (c) Bead reaction - thermal shock method, and (d) Laser induced chemical method for components after dismantling. JAERI in developing techniques are also carrying out melting tests of metal and non-metal. Melting was confirmed to be effective in reducing the volume, homogenizing, and furthermore stabilizing non-metallic wastes. (author)

  19. Development, improvement and calibration of neutronic reaction rates measurements: elaboration of a standard techniques basis

    International Nuclear Information System (INIS)

    Hudelot, J.P.

    1998-06-01

    In order to improve and to validate the neutronics calculation schemes, perfecting integral measurements of neutronics parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronics reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO 2 ) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of 238 U (defined as the ratio of 238 U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for 242 Pu (on MOX rods) and 232 Th (on

  20. Development, improvement and calibration of neutronic reaction rate measurements: elaboration of a base of standard techniques

    International Nuclear Information System (INIS)

    Hudelot, J.P.

    1998-01-01

    In order to improve and to validate the neutronic calculation schemes, perfecting integral measurements of neutronic parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronic reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO 2 ) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of 238 U (defined as the ratio of 238 U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for 242 Pu (on MOX rods) and 232 Th (on Thorium

  1. Comparison of Calibration Techniques for Low-Cost Air Quality Monitoring

    Science.gov (United States)

    Malings, C.; Ramachandran, S.; Tanzer, R.; Kumar, S. P. N.; Hauryliuk, A.; Zimmerman, N.; Presto, A. A.

    2017-12-01

    Assessing the intra-city spatial distribution and temporal variability of air quality can be facilitated by a dense network of monitoring stations. However, the cost of implementing such a network can be prohibitive if high-quality but high-cost monitoring systems are used. To this end, the Real-time Affordable Multi-Pollutant (RAMP) sensor package has been developed at the Center for Atmospheric Particle Studies of Carnegie Mellon University, in collaboration with SenSevere LLC. This self-contained unit can measure up to five gases out of CO, SO2, NO, NO2, O3, VOCs, and CO2, along with temperature and relative humidity. Responses of individual gas sensors can vary greatly even when exposed to the same ambient conditions. Those of VOC sensors in particular were observed to vary by a factor-of-8, which suggests that each sensor requires its own calibration model. To this end, we apply and compare two different calibration methods to data collected by RAMP sensors collocated with a reference monitor station. The first method, random forest (RF) modeling, is a rule-based method which maps sensor responses to pollutant concentrations by implementing a trained sequence of decision rules. RF modeling has previously been used for other RAMP gas sensors by the group, and has produced precise calibrated measurements. However, RF models can only predict pollutant concentrations within the range observed in the training data collected during the collocation period. The second method, Gaussian process (GP) modeling, is a probabilistic Bayesian technique whereby broad prior estimates of pollutant concentrations are updated using sensor responses to generate more refined posterior predictions, as well as allowing predictions beyond the range of the training data. The accuracy and precision of these techniques are assessed and compared on VOC data collected during the summer of 2017 in Pittsburgh, PA. By combining pollutant data gathered by each RAMP sensor and applying

  2. A neutron calibration technique for detectors with low neutron/high photon sensitivity

    International Nuclear Information System (INIS)

    Jahr, R.; Guldbakke, S.; Cosack, M.; Dietze, G.; Klein, H.

    1978-03-01

    The neutron response of a detector with low neutron-/high photon sensitivity is given by the difference of two terms: the response to the mixed neutron-photon field, measured directly, and the response to the photons, deduced from additional measurements with a photon spectrometer. The technique is particularly suited for use in connection with targets which consist of a thick backing and thin layer of neutron producing material such as T, D, Li nuclei. Then the photon component of the mixed field is very nearly the same as the pure photon field from a 'phantom target', being identical with the neutron producing target except for the missing neutron producing material. Using this technique in connection with a T target (Ti-T-layer on silver backing) and the corresponding phantom target (Ti-layer on silver backing), a GM counter was calibrated at a neutron energy of 2.5 MeV. Possibilities are discussed to subsequently calibrate the GM counter at other neutron energies without the use of the photon spectrometer. (orig./HP) [de

  3. Volume reduction philosophy and techniques in use or planned

    Energy Technology Data Exchange (ETDEWEB)

    Row, T.H.

    1984-01-01

    Siting and development of nuclear waste disposal facilities is an expensive task. In the private sector, such developments face siting and licensing issues, public intervention, and technology challenges. The United States Department of Energy (DOE) faces similar challenges in the management of waste generated by the research and production facilities. Volume reduction can be used to lengthen the service life of existing facilities. A wide variety of volume reduction techniques are applied to different waste forms. Compressible waste is compacted into drums, cardboard and metal boxes, and the loaded drums are supercompacted into smaller units. Large metallic items are size-reduced and melted for recycle or sent to shallow land burial. Anaerobic digestion is a process that can reduce cellulosic and animal wastes by 80%. Incinerators of all types have been investigated for application to nuclear wastes and a number of installations operate or are constructing units for low-level and transuranic solid and liquid combustibles. Technology may help solve many of the problems in volume reduction, but the human element also has an important part in solving the puzzle. Aggressive educational campaigns at two sites have proved very successful in reducing waste generation. This overview of volume reduction is intended to transfer the current information from many DOE facilities. 44 references, 85 figures, 5 tables.

  4. Volume reduction philosophy and techniques in use or planned

    International Nuclear Information System (INIS)

    Row, T.H.

    1984-01-01

    Siting and development of nuclear waste disposal facilities is an expensive task. In the private sector, such developments face siting and licensing issues, public intervention, and technology challenges. The United States Department of Energy (DOE) faces similar challenges in the management of waste generated by the research and production facilities. Volume reduction can be used to lengthen the service life of existing facilities. A wide variety of volume reduction techniques are applied to different waste forms. Compressible waste is compacted into drums, cardboard and metal boxes, and the loaded drums are supercompacted into smaller units. Large metallic items are size-reduced and melted for recycle or sent to shallow land burial. Anaerobic digestion is a process that can reduce cellulosic and animal wastes by 80%. Incinerators of all types have been investigated for application to nuclear wastes and a number of installations operate or are constructing units for low-level and transuranic solid and liquid combustibles. Technology may help solve many of the problems in volume reduction, but the human element also has an important part in solving the puzzle. Aggressive educational campaigns at two sites have proved very successful in reducing waste generation. This overview of volume reduction is intended to transfer the current information from many DOE facilities. 44 references, 85 figures, 5 tables

  5. A safeguards verification technique for solution homogeneity and volume measurements in process tanks

    International Nuclear Information System (INIS)

    Suda, S.; Franssen, F.

    1987-01-01

    A safeguards verification technique is being developed for determining whether process-liquid homogeneity has been achieved in process tanks and for authenticating volume-measurement algorithms involving temperature corrections. It is proposed that, in new designs for bulk-handling plants employing automated process lines, bubbler probes and thermocouples be installed at several heights in key accountability tanks. High-accuracy measurements of density using an electromanometer can now be made which match or even exceed analytical-laboratory accuracies. Together with regional determination of tank temperatures, these measurements provide density, liquid-column weight and temperature gradients over the fill range of the tank that can be used to ascertain when the tank solution has reached equilibrium. Temperature-correction algorithms can be authenticated by comparing the volumes obtained from the several bubbler-probe liquid-height measurements, each based on different amounts of liquid above and below the probe. The verification technique is based on the automated electromanometer system developed by Brookhaven National Laboratory (BNL). The IAEA has recently approved the purchase of a stainless-steel tank equipped with multiple bubbler and thermocouple probes for installation in its Bulk Calibration Laboratory at IAEA Headquarters, Vienna. The verification technique is scheduled for preliminary trials in late 1987

  6. Impact of automatic calibration techniques on HMD life cycle costs and sustainable performance

    Science.gov (United States)

    Speck, Richard P.; Herz, Norman E., Jr.

    2000-06-01

    Automatic test and calibration has become a valuable feature in many consumer products--ranging from antilock braking systems to auto-tune TVs. This paper discusses HMDs (Helmet Mounted Displays) and how similar techniques can reduce life cycle costs and increase sustainable performance if they are integrated into a program early enough. Optical ATE (Automatic Test Equipment) is already zeroing distortion in the HMDs and thereby making binocular displays a practical reality. A suitcase sized, field portable optical ATE unit could re-zero these errors in the Ready Room to cancel the effects of aging, minor damage and component replacement. Planning on this would yield large savings through relaxed component specifications and reduced logistic costs. Yet, the sustained performance would far exceed that attained with fixed calibration strategies. Major tactical benefits can come from reducing display errors, particularly in information fusion modules and virtual `beyond visual range' operations. Some versions of the ATE described are in production and examples of high resolution optical test data will be discussed.

  7. Verification Techniques for Parameter Selection and Bayesian Model Calibration Presented for an HIV Model

    Science.gov (United States)

    Wentworth, Mami Tonoe

    Uncertainty quantification plays an important role when making predictive estimates of model responses. In this context, uncertainty quantification is defined as quantifying and reducing uncertainties, and the objective is to quantify uncertainties in parameter, model and measurements, and propagate the uncertainties through the model, so that one can make a predictive estimate with quantified uncertainties. Two of the aspects of uncertainty quantification that must be performed prior to propagating uncertainties are model calibration and parameter selection. There are several efficient techniques for these processes; however, the accuracy of these methods are often not verified. This is the motivation for our work, and in this dissertation, we present and illustrate verification frameworks for model calibration and parameter selection in the context of biological and physical models. First, HIV models, developed and improved by [2, 3, 8], describe the viral infection dynamics of an HIV disease. These are also used to make predictive estimates of viral loads and T-cell counts and to construct an optimal control for drug therapy. Estimating input parameters is an essential step prior to uncertainty quantification. However, not all the parameters are identifiable, implying that they cannot be uniquely determined by the observations. These unidentifiable parameters can be partially removed by performing parameter selection, a process in which parameters that have minimal impacts on the model response are determined. We provide verification techniques for Bayesian model calibration and parameter selection for an HIV model. As an example of a physical model, we employ a heat model with experimental measurements presented in [10]. A steady-state heat model represents a prototypical behavior for heat conduction and diffusion process involved in a thermal-hydraulic model, which is a part of nuclear reactor models. We employ this simple heat model to illustrate verification

  8. A finite volume solver for three dimensional debris flow simulations based on a single calibration parameter

    Science.gov (United States)

    von Boetticher, Albrecht; Turowski, Jens M.; McArdell, Brian; Rickenmann, Dieter

    2016-04-01

    Debris flows are frequent natural hazards that cause massive damage. A wide range of debris flow models try to cover the complex flow behavior that arises from the inhomogeneous material mixture of water with clay, silt, sand, and gravel. The energy dissipation between moving grains depends on grain collisions and tangential friction, and the viscosity of the interstitial fine material suspension depends on the shear gradient. Thus a rheology description needs to be sensitive to the local pressure and shear rate, making the three-dimensional flow structure a key issue for flows in complex terrain. Furthermore, the momentum exchange between the granular and fluid phases should account for the presence of larger particles. We model the fine material suspension with a Herschel-Bulkley rheology law, and represent the gravel with the Coulomb-viscoplastic rheology of Domnik & Pudasaini (Domnik et al. 2013). Both composites are described by two phases that can mix; a third phase accounting for the air is kept separate to account for the free surface. The fluid dynamics are solved in three dimensions using the finite volume open-source code OpenFOAM. Computational costs are kept reasonable by using the Volume of Fluid method to solve only one phase-averaged system of Navier-Stokes equations. The Herschel-Bulkley parameters are modeled as a function of water content, volumetric solid concentration of the mixture, clay content and its mineral composition (Coussot et al. 1989, Yu et al. 2013). The gravel phase properties needed for the Coulomb-viscoplastic rheology are defined by the angle of repose of the gravel. In addition to this basic setup, larger grains and the corresponding grain collisions can be introduced by a coupled Lagrangian particle simulation. Based on the local Savage number a diffusive term in the gravel phase can activate phase separation. The resulting model can reproduce the sensitivity of the debris flow to water content and channel bed roughness, as

  9. Calibration of radionuclides with decay trough beta emission or electron capture by liquid scintillation technique

    International Nuclear Information System (INIS)

    Loureiro, Jamir dos Santos

    2000-02-01

    In this work is reported a methodology a methodology for pure beta and electron capture radionuclides standardization, suing liquid scintillation technique. In this sense the CIEMAT/NIST method, recently utilized by international laboratories, was implemented and the lack in the Laboratorio Nacional das Radiacoes Ionizantes - LNMRI, of the Comissao Nacional de Energia Nuclear - CNEN, for adequate methodology to standardize this kind if radionuclides was filled, fact that was not present with alpha and gamma radionuclides. The implementation procedure evaluation was provided by concentration activity determination of the following radionuclides: 14 C and 90 Sr, pure beta emitters; 55 Fe, electron capture decay; 204 Tl, electron capture and beta decay and 60 Co, beta-gamma emitter. In this way, a careful analysis of the implementation procedure with these radionuclides types, ranging on a broad energy spectral, was possible. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. Besides this intercomparisons, one was provided with a 204 Tl solution, utilized in the international comparison recently promoted by BIPM, and another one with a 60 C solution calibrated in LNMRI/CNEN previously by a relative calibration system, with a well type pressurized ionization chamber, and an absolute beta-gamma coincidence system, with a pill-box type proportional counter 4 π geometry, coupled with a scintillator system with a sodium iodide cristal of 4x4 inches. The comparisons among LNMRI/CNEN results and the reference values, showed a small deviation of 1,32% for 14 C, 0,40% for 60 Co, 1,12% for 55 Fe, 0,10% for 90 Sr and 0,73% for 204 Tl. For the BIPM solution the deviation was 0,46% and for 60 Co

  10. Development and application of a calibration technique for laser ablation - ICP - MS

    Energy Technology Data Exchange (ETDEWEB)

    Boue-Bigne, F

    2000-08-20

    Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS) is a powerful analytical technique for the direct elemental analysis of solid samples, with spatial resolution down to a few microns. However, calibration remains the limiting factor in obtaining quantitative analysis by LA-ICP-MS for a wide range of sample types. No universal method exists as yet and the ones that are currently used tend to employ matrix-matched solid standards. Matrix-matched solid standards are not available for many types of sample, such as polymers, biological materials, fluid inclusions, etc. The need for a universal method of calibration that involves standards that are easy to prepare and suitable for any type of sample is required. Additional to matrix-matching, internal standards are widely used in LA-ICP-MS for quantitative analyses. The internal standard compensates for the different ablation yields from the sample and the standard and for the laser shot-to-shot variation. Given that the use of an internal standard is required to obtain reliable results, the need for matrix-matching might be regarded as questionable. This project has focused on the development and application of a new method of calibration for LA-ICP-MS. It involves the use of aqueous standards whose absorption characteristics are modified by the addition of a chromophore to the solution. Additives were selected for ablation with KrF excimer, and Nd:YAG lasers. The influence of the additive concentration on the ablation yield was investigated for different laser energies. Response curves were obtained showing that as the additive concentration was increased, less energy was required to ablate the modified standard solutions efficiently. A general procedure was then defined for the preparation and use of the modified standard solutions for a given sample. The new method of calibration was used for the quantitative analysis of different sample types: low density polyethylene (LDPE), polyketone (PK

  11. Development and application of a calibration technique for laser ablation - ICP - MS

    International Nuclear Information System (INIS)

    Boue-Bigne, F.

    2000-01-01

    Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS) is a powerful analytical technique for the direct elemental analysis of solid samples, with spatial resolution down to a few microns. However, calibration remains the limiting factor in obtaining quantitative analysis by LA-ICP-MS for a wide range of sample types. No universal method exists as yet and the ones that are currently used tend to employ matrix-matched solid standards. Matrix-matched solid standards are not available for many types of sample, such as polymers, biological materials, fluid inclusions, etc. The need for a universal method of calibration that involves standards that are easy to prepare and suitable for any type of sample is required. Additional to matrix-matching, internal standards are widely used in LA-ICP-MS for quantitative analyses. The internal standard compensates for the different ablation yields from the sample and the standard and for the laser shot-to-shot variation. Given that the use of an internal standard is required to obtain reliable results, the need for matrix-matching might be regarded as questionable. This project has focused on the development and application of a new method of calibration for LA-ICP-MS. It involves the use of aqueous standards whose absorption characteristics are modified by the addition of a chromophore to the solution. Additives were selected for ablation with KrF excimer, and Nd:YAG lasers. The influence of the additive concentration on the ablation yield was investigated for different laser energies. Response curves were obtained showing that as the additive concentration was increased, less energy was required to ablate the modified standard solutions efficiently. A general procedure was then defined for the preparation and use of the modified standard solutions for a given sample. The new method of calibration was used for the quantitative analysis of different sample types: low density polyethylene (LDPE), polyketone (PK

  12. A clinical technique for virtual articulator mounting with natural head position by using calibrated stereophotogrammetry.

    Science.gov (United States)

    Lam, Walter Y H; Hsung, Richard T C; Choi, Winnie W S; Luk, Henry W K; Cheng, Leo Y Y; Pow, Edmond H N

    2017-09-29

    Accurate articulator-mounted casts are essential for occlusion analysis and for fabrication of dental prostheses. Although the axis orbital plane has been commonly used as the reference horizontal plane, some clinicians prefer to register the horizontal plane with a spirit level when the patient is in the natural head position (NHP) to avoid anatomic landmark variations. This article presents a digital workflow for registering the patient's horizontal plane in NHP on a virtual articulator. An orientation reference board is used to calibrate a stereophotogrammetry device and a 3-dimensional facial photograph with the patient in NHP. The horizontal plane can then be automatically registered to the patient's virtual model and aligned to the virtual articulator at the transverse horizontal axis level. This technique showed good repeatability with positional differences of less than 1 degree and 1 mm in 5 repeated measurements in 1 patient. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  13. Calibrated Phase-Shifting Digital Holographic Microscope Using a Sampling Moiré Technique

    Directory of Open Access Journals (Sweden)

    Peng Xia

    2018-05-01

    Full Text Available A calibrated phase-shifting digital holographic microscope system capable of improving the quality of reconstructed images is proposed. Phase-shifting errors are introduced in phase-shifted holograms for numerous reasons, such as the non-linearity of piezoelectric transducers (PZTs, wavelength fluctuations in lasers, and environmental disturbances, leading to poor-quality reconstructions. In our system, in addition to the camera used to record object information, an extra camera is used to record interferograms, which are used to analyze phase-shifting errors using a sampling Moiré technique. The quality of the reconstructed object images can be improved by the phase-shifting error compensation algorithm. Both the numerical simulation and experiment demonstrate the effectiveness of the proposed system.

  14. Assessment of calibration parameters for an aerial gamma spectrometry system using Monte-Carlo technique

    International Nuclear Information System (INIS)

    Srinivasan, P.; Raman, Anand; Sharma, D.N.

    2009-01-01

    Aerial gamma spectrometry is a very effective method for quickly surveying a large area, which might get contaminated following a nuclear accident, or due to nuclear weapon fallout. The technique not only helps in identifying the contaminating radionuclide but also in assessing the magnitude and the extent of contamination. These two factors are of importance for the authorities to quickly plan and execute effective counter measures and controls if required. The development of Airborne gamma ray spectrometry systems have been reported by different institutions. The application of these systems have been reported by different authors. Radiation Safety Systems Division of the Bhabha Atomic Research Centre has developed an Aerial Gamma Spectrometry System (AGSS) and the surveying methodology. For an online assessment of the contamination levels, it is essential to calibrate the system (AGSS) either flying it over a known contaminated area or over a simulated contaminated surface by deploying sealed sources on the ground. AGSS has been calibrated for different detectors in aerial exercises using such simulated contamination on the ground. The calibration methodology essentially needs net photo-peak counts in selected energy windows to finally arrive at the Air to Ground Correlation Factors at selected flight parameters such as altitude, speed of flight and the time interval at which each spectrum is acquired. This paper describes the methodology to predict all the necessary parameters like photon fluence at various altitudes, the photo-peak counts in different energy windows, Air to Ground Correlation Factors(AGCF), the dose rate at any height due to air scattered gamma ray photons etc. These parameters are predicted for a given source deployment matrix, detector and altitude of flying using the Monte-Carlo code MCNP (Monte Carlo Neutron and Photon Transport Code.CCC-200, RSIC, ORNL, Tennessee, USA). A methodology to generate the completely folded gamma ray count

  15. Calibration and measurement of {sup 210}Pb using two independent techniques

    Energy Technology Data Exchange (ETDEWEB)

    Villa, M. [Centro de Investigacion, Tecnologia e Innovacion, CITIUS, Universidad de Sevilla, Av. Reina Mercedes 4B, 41012 Sevilla (Spain)], E-mail: mvilla@us.es; Hurtado, S. [Centro de Investigacion, Tecnologia e Innovacion, CITIUS, Universidad de Sevilla, Av. Reina Mercedes 4B, 41012 Sevilla (Spain); Manjon, G.; Garcia-Tenorio, R. [Departamento de Fisica Aplicada II, E.T.S. Arquitectura, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 Sevilla (Spain)

    2007-10-15

    An experimental procedure has been developed for a rapid and accurate determination of the activity concentration of {sup 210}Pb in sediments by liquid scintillation counting (LSC). Additionally, an alternative technique using {gamma}-spectrometry and Monte Carlo simulation has been developed. A radiochemical procedure, based on radium and barium sulphates co-precipitation have been applied to isolate the Pb-isotopes. {sup 210}Pb activity measurements were done in a low background scintillation spectrometer Quantulus 1220. A calibration of the liquid scintillation spectrometer, including its {alpha}/{beta} discrimination system, has been made, in order to minimize background and, additionally, some improvements are suggested for the calculation of the {sup 210}Pb activity concentration, taking into account that {sup 210}Pb counting efficiency cannot be accurately determined. Therefore, the use of an effective radiochemical yield, which can be empirically evaluated, is proposed. {sup 210}Pb activity concentration in riverbed sediments from an area affected by NORM wastes has been determined using both the proposed method. Results using {gamma}-spectrometry and LSC are compared to the results obtained following indirect {alpha}-spectrometry ({sup 210}Po) method.

  16. Energy calibration of CsI(Tl) scintillator in pulse-shape identification technique

    CERN Document Server

    Avdeichikov, V; Golubev, P; Jakobsson, B; Colonna, N

    2003-01-01

    A batch of 16 CsI(Tl) scintillator crystals, supplied by the Bicron Company, has been studied with respect to precise energy calibration in pulse-shape identification technique. The light corresponding to pulse integration within the time interval 1.6-4.5 mu s (long gate) and 0.0-4.5 mu s (extra-long gate) exhibits a power law relation, L(E,Z,A)=a1(Z,A)E sup a sup 2 sup ( sup Z sup , sup A sup ) , for sup 1 sup , sup 2 sup , sup 3 H isotopes in the measured energy range 5-150 MeV. For the time interval 0.0-0.60 mu s (short gate), a significant deviation from the power law relation is observed, for energy greater than approx 30 MeV. The character of the a2(p)-a2(d) and a2(p)-a2(t) correlations for protons, deuterons and tritons, reveals 3 types of crystals in the batch. These subbatches differ in the value of the extracted parameter a2 for protons, and in the value of the spread of a2 for deuterons and tritons. This may be explained by the difference in the energy dependence of the fast decay time component an...

  17. Clouds and the Earth's Radiant Energy System (CERES) algorithm theoretical basis document. volume 2; Geolocation, calibration, and ERBE-like analyses (subsystems 1-3)

    Science.gov (United States)

    Wielicki, B. A. (Principal Investigator); Barkstrom, B. R. (Principal Investigator); Charlock, T. P.; Baum, B. A.; Green, R. N.; Minnis, P.; Smith, G. L.; Coakley, J. A.; Randall, D. R.; Lee, R. B., III

    1995-01-01

    The theoretical bases for the Release 1 algorithms that will be used to process satellite data for investigation of the Clouds and Earth's Radiant Energy System (CERES) are described. The architecture for software implementation of the methodologies is outlined. Volume 2 details the techniques used to geolocate and calibrate the CERES scanning radiometer measurements of shortwave and longwave radiance to invert the radiances to top-of-the-atmosphere (TOA) and surface fluxes following the Earth Radiation Budget Experiment (ERBE) approach, and to average the fluxes over various time and spatial scales to produce an ERBE-like product. Spacecraft ephemeris and sensor telemetry are used with calibration coefficients to produce a chronologically ordered data product called bidirectional scan (BDS) radiances. A spatially organized instrument Earth scan product is developed for the cloud-processing subsystem. The ERBE-like inversion subsystem converts BDS radiances to unfiltered instantaneous TOA and surface fluxes. The TOA fluxes are determined by using established ERBE techniques. Hourly TOA fluxes are computed from the instantaneous values by using ERBE methods. Hourly surface fluxes are estimated from TOA fluxes by using simple parameterizations based on recent research. The averaging process produces daily, monthly-hourly, and monthly means of TOA and surface fluxes at various scales. This product provides a continuation of the ERBE record.

  18. A new technique for the calibration of neutron probes by volumetric method

    International Nuclear Information System (INIS)

    Encarnacao, F.A.F. da.

    1988-01-01

    Laboratory and field studies were performed for the determination of a calibration curve of a neutron probe in three different kinds of soils: Red Yellow PODZOLIC, LITOLIC and ALLUVIAL, in the last one laboratory studies were done to determine local humidity on the calibration curve parameters. (A.C.A.S.) [pt

  19. Meteorological Sensor Array (MSA)-Phase I. Volume 3 (Pre-Field Campaign Sensor Calibration)

    Science.gov (United States)

    2015-07-01

    Phase I thermodynamic sensors (barometers, thermometers, hygrometers, and pyranometers ). This report documents the results of a detailed calibration...barometer, thermometer, hydrometer, pyranometer 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER...60 (02 Mar); the logger associated with each non-standard RH sensor is demonstrated in the legend ...............21 Fig. 16 Pyranometers percent

  20. Reduction of radioactive waste volumes by using supercompaction technique

    International Nuclear Information System (INIS)

    Santos, John Wagner A.; Lima, Sandro Leonardo N. de

    2007-01-01

    The Radioactive Waste Management Program from ELETRONUCLEAR comprises the use of techniques and technologies to reduce the volumes of processed radwaste, which aims to improve the storage capacity and also assure the protection for the environment, as part of ELETRONUCLEAR's business strategy. The Angra site stores radwaste in temporary storage facilities, named Store number 1 and Store number 2, which are routinely managed and surveyed periodically by the ELETRONUCLEAR's Radiological Protection Division and submitted to frequent CNEN inspections. Medium level and low level radwastes are stored on those storage facilities. In January 2005, ELETRONUCLEAR decided to realize the Supercompaction of drums with compacted radwaste, mostly from Angra 1 and a little from Angra 2. By that time, the Store 1 was near to achieve its nominal capacity; this situation demanded a prompt response, and the chosen option was to proceed the supercompaction by using a mobile supercompactor unit. In April, 2006, two thousand and twenty seven drums of 200 liters were supercompacted at the plant site, and as a result, the initial storage area became sufficient to store drums for about five more years of operation. The supercompaction process is achieved by using a hydraulic press with extra high force. The pellets (crashed drums) were placed inside a special metallic box with 2500 liters of capacity (the overpack). This operation produced 128 full boxes, varying from 12 to 19 pellets inside each box, and the boxes were stored inside the Store 1. (author)

  1. Generic Techniques for the Calibration of Robots with Application of the 3-D Fixtures and Statistical Technique on the PUMA 500 and ARID Robots

    Science.gov (United States)

    Tawfik, Hazem

    1991-01-01

    A relatively simple, inexpensive, and generic technique that could be used in both laboratories and some operation site environments is introduced at the Robotics Applications and Development Laboratory (RADL) at Kennedy Space Center (KSC). In addition, this report gives a detailed explanation of the set up procedure, data collection, and analysis using this new technique that was developed at the State University of New York at Farmingdale. The technique was used to evaluate the repeatability, accuracy, and overshoot of the Unimate Industrial Robot, PUMA 500. The data were statistically analyzed to provide an insight into the performance of the systems and components of the robot. Also, the same technique was used to check the forward kinematics against the inverse kinematics of RADL's PUMA robot. Recommendations were made for RADL to use this technique for laboratory calibration of the currently existing robots such as the ASEA, high speed controller, Automated Radiator Inspection Device (ARID) etc. Also, recommendations were made to develop and establish other calibration techniques that will be more suitable for site calibration environment and robot certification.

  2. Calibration technique and study on metrological characteristics of a high-voltage inverse square-law function generator

    International Nuclear Information System (INIS)

    Popov, V.P.; Semenov, A.L.

    1987-01-01

    The calibration technique is described, and the metrological characteristics of a high-voltage generator of the inverse-quadratic function (HGF), being a functional unit of the diagnostic system of an electrodynamic analyser of a ionic component of a laser plasma, is analysed. The results of HGF testing in the range of time constants of the τ=(5-25)μs function are given. Analysis of metrologic and experimental characteristics shows, that HGF with automatic calibration has quite high accurate parameters. The high accuracy of function generation is provided with the possibility of calibration and adjustment conduction under experimental working conditions. Increase of the generated pulse amplitude to several tens of kilovelts is possible. Besides, the possibility of timely function adjustment to the necessary parameter (τ) increases essentially the HGF functional possibilities

  3. An experimental result of estimating an application volume by machine learning techniques.

    Science.gov (United States)

    Hasegawa, Tatsuhito; Koshino, Makoto; Kimura, Haruhiko

    2015-01-01

    In this study, we improved the usability of smartphones by automating a user's operations. We developed an intelligent system using machine learning techniques that periodically detects a user's context on a smartphone. We selected the Android operating system because it has the largest market share and highest flexibility of its development environment. In this paper, we describe an application that automatically adjusts application volume. Adjusting the volume can be easily forgotten because users need to push the volume buttons to alter the volume depending on the given situation. Therefore, we developed an application that automatically adjusts the volume based on learned user settings. Application volume can be set differently from ringtone volume on Android devices, and these volume settings are associated with each specific application including games. Our application records a user's location, the volume setting, the foreground application name and other such attributes as learning data, thereby estimating whether the volume should be adjusted using machine learning techniques via Weka.

  4. In-flight interband calibration on AVHRR data by a cloud-viewing technique

    OpenAIRE

    Wald , Lucien

    1997-01-01

    ISBN 90-5410-933-5; International audience; A significant degradation in the responsivity of the AVHRR radiometers aboard the NOAA satellite series, affects the index vegetation (NDVI), which is an important source of information for monitoring vegetation conditions on regional and global scales. Many studies have been carried out which use the viewing Earth calibration approach in order to provide accurate calibration correction coefficients for the computation of the vegetation index using ...

  5. Evaluation of Automated Model Calibration Techniques for Residential Building Energy Simulation

    Energy Technology Data Exchange (ETDEWEB)

    and Ben Polly, Joseph Robertson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Polly, Ben [National Renewable Energy Lab. (NREL), Golden, CO (United States); Collis, Jon [Colorado School of Mines, Golden, CO (United States)

    2013-09-01

    This simulation study adapts and applies the general framework described in BESTEST-EX (Judkoff et al 2010) for self-testing residential building energy model calibration methods. BEopt/DOE-2.2 is used to evaluate four mathematical calibration methods in the context of monthly, daily, and hourly synthetic utility data for a 1960's-era existing home in a cooling-dominated climate. The home's model inputs are assigned probability distributions representing uncertainty ranges, random selections are made from the uncertainty ranges to define "explicit" input values, and synthetic utility billing data are generated using the explicit input values. The four calibration methods evaluated in this study are: an ASHRAE 1051-RP-based approach (Reddy and Maor 2006), a simplified simulated annealing optimization approach, a regression metamodeling optimization approach, and a simple output ratio calibration approach. The calibration methods are evaluated for monthly, daily, and hourly cases; various retrofit measures are applied to the calibrated models and the methods are evaluated based on the accuracy of predicted savings, computational cost, repeatability, automation, and ease of implementation.

  6. Evaluation of Automated Model Calibration Techniques for Residential Building Energy Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, J.; Polly, B.; Collis, J.

    2013-09-01

    This simulation study adapts and applies the general framework described in BESTEST-EX (Judkoff et al 2010) for self-testing residential building energy model calibration methods. BEopt/DOE-2.2 is used to evaluate four mathematical calibration methods in the context of monthly, daily, and hourly synthetic utility data for a 1960's-era existing home in a cooling-dominated climate. The home's model inputs are assigned probability distributions representing uncertainty ranges, random selections are made from the uncertainty ranges to define 'explicit' input values, and synthetic utility billing data are generated using the explicit input values. The four calibration methods evaluated in this study are: an ASHRAE 1051-RP-based approach (Reddy and Maor 2006), a simplified simulated annealing optimization approach, a regression metamodeling optimization approach, and a simple output ratio calibration approach. The calibration methods are evaluated for monthly, daily, and hourly cases; various retrofit measures are applied to the calibrated models and the methods are evaluated based on the accuracy of predicted savings, computational cost, repeatability, automation, and ease of implementation.

  7. Accurate technique for complete geometric calibration of cone-beam computed tomography systems

    International Nuclear Information System (INIS)

    Cho Youngbin; Moseley, Douglas J.; Siewerdsen, Jeffrey H.; Jaffray, David A.

    2005-01-01

    Cone-beam computed tomography systems have been developed to provide in situ imaging for the purpose of guiding radiation therapy. Clinical systems have been constructed using this approach, a clinical linear accelerator (Elekta Synergy RP) and an iso-centric C-arm. Geometric calibration involves the estimation of a set of parameters that describes the geometry of such systems, and is essential for accurate image reconstruction. We have developed a general analytic algorithm and corresponding calibration phantom for estimating these geometric parameters in cone-beam computed tomography (CT) systems. The performance of the calibration algorithm is evaluated and its application is discussed. The algorithm makes use of a calibration phantom to estimate the geometric parameters of the system. The phantom consists of 24 steel ball bearings (BBs) in a known geometry. Twelve BBs are spaced evenly at 30 deg in two plane-parallel circles separated by a given distance along the tube axis. The detector (e.g., a flat panel detector) is assumed to have no spatial distortion. The method estimates geometric parameters including the position of the x-ray source, position, and rotation of the detector, and gantry angle, and can describe complex source-detector trajectories. The accuracy and sensitivity of the calibration algorithm was analyzed. The calibration algorithm estimates geometric parameters in a high level of accuracy such that the quality of CT reconstruction is not degraded by the error of estimation. Sensitivity analysis shows uncertainty of 0.01 deg. (around beam direction) to 0.3 deg. (normal to the beam direction) in rotation, and 0.2 mm (orthogonal to the beam direction) to 4.9 mm (beam direction) in position for the medical linear accelerator geometry. Experimental measurements using a laboratory bench Cone-beam CT system of known geometry demonstrate the sensitivity of the method in detecting small changes in the imaging geometry with an uncertainty of 0.1 mm in

  8. White Sands Missile Range 2007 Urban Study: Data Processing - Volume DP-1 (Sonic Calibration)

    Science.gov (United States)

    2008-09-01

    calibrated in a wind tunnel against a NIST standard were positioned at the two ends of the lineup , closest to the buildings (positions 1 and 10 in...utilized westerly winds between 8 and 10 m/s (2007 February 24, 0600–0605 LT). The 5 min of data utilized by the “fast” case were sequential . The...2.4–11.2 m/s. The 5-min “variable” case utilized sequential minutes. Results from all three WS conditions were the following (Vaucher, 2007a

  9. Larger Optics and Improved Calibration Techniques for Small Satellite Observations with the ERAU OSCOM System

    Science.gov (United States)

    Bilardi, S.; Barjatya, A.; Gasdia, F.

    OSCOM, Optical tracking and Spectral characterization of CubeSats for Operational Missions, is a system capable of providing time-resolved satellite photometry using commercial-off-the-shelf (COTS) hardware and custom tracking and analysis software. This system has acquired photometry of objects as small as CubeSats using a Celestron 11” RASA and an inexpensive CMOS machine vision camera. For satellites with known shapes, these light curves can be used to verify a satellite’s attitude and the state of its deployed solar panels or antennae. While the OSCOM system can successfully track satellites and produce light curves, there is ongoing improvement towards increasing its automation while supporting additional mounts and telescopes. A newly acquired Celestron 14” Edge HD can be used with a Starizona Hyperstar to increase the SNR for small objects as well as extend beyond the limiting magnitude of the 11” RASA. OSCOM currently corrects instrumental brightness measurements for satellite range and observatory site average atmospheric extinction, but calibrated absolute brightness is required to determine information about satellites other than their spin rate, such as surface albedo. A calibration method that automatically detects and identifies background stars can use their catalog magnitudes to calibrate the brightness of the satellite in the image. We present a photometric light curve from both the 14” Edge HD and 11” RASA optical systems as well as plans for a calibration method that will perform background star photometry to efficiently determine calibrated satellite brightness in each frame.

  10. Establishment of 60Co dose calibration curve using fluorescent in situ hybridization assay technique: Result of preliminary study

    International Nuclear Information System (INIS)

    Rahimah Abdul Rahim; Noriah Jamal; Noraisyah Mohd Yusof; Juliana Mahamad Napiah; Nelly Bo Nai Lee

    2010-01-01

    This study aims at establishing an in-vitro 60 Co dose calibration curve using Fluorescent In-Situ Hybridization assay technique for the Malaysian National Bio dosimetry Laboratory. Blood samples collected from a female healthy donor were irradiated with several doses of 60 Co radiation. Following culturing of lymphocytes, microscopic slides are prepared, denatured and hybridized. The frequencies of translocation are estimated in the metaphases. A calibration curve was then generated using a regression technique. It shows a good fit to a linear-quadratic model. The results of this study might be useful in estimating absorbed dose for the individual exposed to ionizing radiation retrospectively. This information may be useful as a guide for medical treatment for the assessment of possible health consequences. (author)

  11. Insights from Synthetic Star-forming Regions. III. Calibration of Measurement and Techniques of Star Formation Rates

    Energy Technology Data Exchange (ETDEWEB)

    Koepferl, Christine M.; Robitaille, Thomas P. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Dale, James E., E-mail: koepferl@usm.lmu.de [University Observatory Munich, Scheinerstr. 1, D-81679 Munich (Germany)

    2017-11-01

    Through an extensive set of realistic synthetic observations (produced in Paper I), we assess in this part of the paper series (Paper III) how the choice of observational techniques affects the measurement of star formation rates (SFRs) in star-forming regions. We test the accuracy of commonly used techniques and construct new methods to extract the SFR, so that these findings can be applied to measure the SFR in real regions throughout the Milky Way. We investigate diffuse infrared SFR tracers such as those using 24 μ m, 70 μ m and total infrared emission, which have been previously calibrated for global galaxy scales. We set up a toy model of a galaxy and show that the infrared emission is consistent with the intrinsic SFR using extra-galactic calibrated laws (although the consistency does not prove their reliability). For local scales, we show that these techniques produce completely unreliable results for single star-forming regions, which are governed by different characteristic timescales. We show how calibration of these techniques can be improved for single star-forming regions by adjusting the characteristic timescale and the scaling factor and give suggestions of new calibrations of the diffuse star formation tracers. We show that star-forming regions that are dominated by high-mass stellar feedback experience a rapid drop in infrared emission once high-mass stellar feedback is turned on, which implies different characteristic timescales. Moreover, we explore the measured SFRs calculated directly from the observed young stellar population. We find that the measured point sources follow the evolutionary pace of star formation more directly than diffuse star formation tracers.

  12. Computed Tomography Colonography Technique: The Role of Intracolonic Gas Volume

    Directory of Open Access Journals (Sweden)

    Patrick D. McLaughlin

    2013-01-01

    Full Text Available Introduction. Poor distention decreases the sensitivity and specificity of CTC. The total volume of gas administered will vary according to many factors. We aim to determine the relationship between the volume of retained gas at the time of image acquisition and colonic distention and specifically the presence of collapsed bowel segments at CTC. Materials and Methods. All patients who underwent CTC over a 12-month period at a single institution were included in the study. Colonic luminal distention was objectively scored by 2 radiologists using an established 4-point scale. Quantitative analysis of the volume of retained gas at the time of image acquisition was conducted using the threshold 3D region growing function of OsiriX. Results. 108 patients were included for volumetric analysis. Mean retained gas volume was 3.3 L. 35% (38/108 of patients had at least one collapsed colonic segment. Significantly lower gas volumes were observed in the patients with collapsed colonic segments when compared with those with fully distended colons 2.6 L versus 3.5 L (P=0.031. Retained volumes were significantly higher for the 78% of patients with ileocecal reflux at 3.4 L versus 2.6 L without ileocecal reflux (P=0.014. Conclusion. Estimation of intraluminal gas volume at CTC is feasible using image segmentation and thresholding tools. An average of 3.5 L of retained gas was found in diagnostically adequate CTC studies with significantly lower mean gas volume observed in patients with collapsed colonic segments.

  13. Scattering cross-sections of common calibration gases measured by IBBCEAS technique

    Directory of Open Access Journals (Sweden)

    S.I. Issac

    Full Text Available In this study, incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS was used to measure scattering cross-sections of a few common gases in the 650–670 nm spectral range relative to that of dry air. Precise measurements of scattering cross-sections of these calibration gases in the visible spectral range are important. The IBBCEAS system developed in the laboratory was calibrated with a low-loss optical window. The measurements made at 660 nm were compared with previously measured cross-section values and found to be in good agreement with the existing measurements. Keywords: IBBCEAS, Rayleigh scattering, Scattering cross section

  14. A time-selective technique for free-field reciprocity calibration of condenser microphones

    DEFF Research Database (Denmark)

    Barrera Figueroa, Salvador; Rasmussen, Knud; Jacobsen, Finn

    2003-01-01

    In normal practice, microphones are calibrated in a closed coupler where the sound pressure is uniformly distributed over the diaphragm. Alternatively, microphones can be placed in a free field, although in that case the distribution of sound pressure over the diaphragm will change as a result of...

  15. Free-field reciprocity calibration of laboratory standard (LS) microphones using a time selective technique

    DEFF Research Database (Denmark)

    Rasmussen, Knud; Barrera Figueroa, Salvador

    2006-01-01

    Although the basic principle of reciprocity calibration of microphones in a free field is simple, the practical problems are complicated due to the low signal-to-noise ratio and the influence of cross talk and reflections from the surroundings. The influence of uncorrelated noise can be reduced...

  16. Calibration of automatic performance measures - speed and volume data: volume 2, evaluation of the accuracy of approach volume counts and speeds collected by microwave sensors.

    Science.gov (United States)

    2016-05-01

    This study evaluated the accuracy of approach volumes and free flow approach speeds collected by the Wavetronix : SmartSensor Advance sensor for the Signal Performance Metrics system of the Utah Department of Transportation (UDOT), : using the field ...

  17. Developing novel techniques for readout, calibration and event selection in the NOvA long-baseline neutrino experiment

    International Nuclear Information System (INIS)

    Patterson, Ryan; Backhouse, Christopher; Bays, Kirk; Lozier, Joseph; Pershey, Daniel

    2016-01-01

    The NOvA long-baseline neutrino experiment uses a fine-grained, low-Z, fully active detector that offers unprecedented electron neutrino identification capabilities for a detector of its scale. In this award's proposal, the PI outlined the development and implementation of novel techniques for channel readout, detector calibration, and event reconstruction that make full use of the strengths of the NOvA detector technology. In particular, this included designing custom event reconstruction algorithms that utilize the rich information available in the substructure of hadronic and electromagnetic showers. Exploiting this information provides not only substantial improvement in background rejection for the electron neutrino search but also better shower energy resolution (improving the precision on measured oscillation parameters) and a high-energy electromagnetic calibration source (through neutral pion events). The PI further proposed developing and deploying a new electronics readout scheme compatible with the existing hardware that can reduce near detector event pile-up and can offer powerful timing information to the reconstruction, allowing for cosmic ray muon tagging via track direction determination, among other things. In conjunction with the above, the PI proposed leading the calibration of the NOvA detectors, including characterizing individual electronics channels, correcting for spatial variations across the detector, and establishing absolute event energy scales. All three of these lines of effort have been successfully completed, feeding directly into the NOvA's recent exciting neutrino oscillation results. The techniques developed under this award are detailed in this final technical report.

  18. Developing novel techniques for readout, calibration and event selection in the NOvA long-baseline neutrino experiment

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ryan [California Inst. of Technology (CalTech), Pasadena, CA (United States); Backhouse, Christopher [California Inst. of Technology (CalTech), Pasadena, CA (United States); Bays, Kirk [California Inst. of Technology (CalTech), Pasadena, CA (United States); Lozier, Joseph [California Inst. of Technology (CalTech), Pasadena, CA (United States); Pershey, Daniel [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-10-01

    The NOvA long-baseline neutrino experiment uses a fine-grained, low-Z, fully active detector that offers unprecedented electron neutrino identification capabilities for a detector of its scale. In this award’s proposal, the PI outlined the development and implementation of novel techniques for channel readout, detector calibration, and event reconstruction that make full use of the strengths of the NOvA detector technology. In particular, this included designing custom event reconstruction algorithms that utilize the rich information available in the substructure of hadronic and electromagnetic showers. Exploiting this information provides not only substantial improvement in background rejection for the electron neutrino search but also better shower energy resolution (improving the precision on measured oscillation parameters) and a high-energy electromagnetic calibration source (through neutral pion events). The PI further proposed developing and deploying a new electronics readout scheme compatible with the existing hardware that can reduce near detector event pile-up and can offer powerful timing information to the reconstruction, allowing for cosmic ray muon tagging via track direction determination, among other things. In conjunction with the above, the PI proposed leading the calibration of the NOvA detectors, including characterizing individual electronics channels, correcting for spatial variations across the detector, and establishing absolute event energy scales. All three of these lines of effort have been successfully completed, feeding directly into the NOvA’s recent exciting neutrino oscillation results. The techniques developed under this award are detailed in this final technical report.

  19. Uncertainty Quantification Techniques for Sensor Calibration Monitoring in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Ramuhalli, Pradeep; Lin, Guang; Crawford, Susan L.; Konomi, Bledar A.; Coble, Jamie B.; Shumaker, Brent; Hashemian, Hash

    2014-04-30

    This report describes research towards the development of advanced algorithms for online calibration monitoring. The objective of this research is to develop the next generation of online monitoring technologies for sensor calibration interval extension and signal validation in operating and new reactors. These advances are expected to improve the safety and reliability of current and planned nuclear power systems as a result of higher accuracies and increased reliability of sensors used to monitor key parameters. The focus of this report is on documenting the outcomes of the first phase of R&D under this project, which addressed approaches to uncertainty quantification (UQ) in online monitoring that are data-driven, and can therefore adjust estimates of uncertainty as measurement conditions change. Such data-driven approaches to UQ are necessary to address changing plant conditions, for example, as nuclear power plants experience transients, or as next-generation small modular reactors (SMR) operate in load-following conditions.

  20. Uncertainty Quantification Techniques for Sensor Calibration Monitoring in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Ramuhalli, Pradeep; Lin, Guang; Crawford, Susan L.; Konomi, Bledar A.; Braatz, Brett G.; Coble, Jamie B.; Shumaker, Brent; Hashemian, Hash

    2013-09-01

    This report describes the status of ongoing research towards the development of advanced algorithms for online calibration monitoring. The objective of this research is to develop the next generation of online monitoring technologies for sensor calibration interval extension and signal validation in operating and new reactors. These advances are expected to improve the safety and reliability of current and planned nuclear power systems as a result of higher accuracies and increased reliability of sensors used to monitor key parameters. The focus of this report is on documenting the outcomes of the first phase of R&D under this project, which addressed approaches to uncertainty quantification (UQ) in online monitoring that are data-driven, and can therefore adjust estimates of uncertainty as measurement conditions change. Such data-driven approaches to UQ are necessary to address changing plant conditions, for example, as nuclear power plants experience transients, or as next-generation small modular reactors (SMR) operate in load-following conditions.

  1. New decontamination techniques generating a low volume of effluent

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    This document presents some decontamination techniques, their principles, characteristics and advantages and provides references on the subject. Techniques as foam and spray foam decontamination, dry steam decontamination, electro-decontamination and gel decontamination are presented. A presentation of TRIADE, cleanup dismantling servicing, is also provided. (A.L.B.)

  2. New decontamination techniques generating a low volume of effluent

    International Nuclear Information System (INIS)

    2002-01-01

    This document presents some decontamination techniques, their principles, characteristics and advantages and provides references on the subject. Techniques as foam and spray foam decontamination, dry steam decontamination, electro-decontamination and gel decontamination are presented. A presentation of TRIADE, cleanup dismantling servicing, is also provided. (A.L.B.)

  3. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    Czech Academy of Sciences Publication Activity Database

    Abat, E.; Abdallah, J.M.; Addy, T.N.; Lokajíček, Miloš; Němeček, Stanislav

    2010-01-01

    Roč. 6, č. 6 (2010), P06001/1-P06001/28 ISSN 1748-0221 R&D Projects: GA MŠk LA08047 Institutional research plan: CEZ:AV0Z10100502 Keywords : ATLAS * calorimeter methods * calorimeters * detector modelling and simulations * pattern recognition * cluster finding * calibration and fitting methods Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 3.148, year: 2010

  4. Calibration and statistical techniques for building an interactive screen for learning of alphabets by children

    Directory of Open Access Journals (Sweden)

    Riby Abraham Boby

    2017-05-01

    Full Text Available This article focuses on the implementation details of a portable interactive device called Image-projective Desktop Varnamala Trainer. The device uses a projector to produce a virtual display on a flat surface. For enabling interaction, the information about a user’s hand movement is obtained from a single two-dimensional scanning laser range finder in contrast with a camera sensor used in many earlier applications. A generalized calibration process to obtain exact transformation from projected screen coordinate system to sensor coordinate system is proposed in this article and implemented for enabling interaction. This permits production of large interactive displays with minimal cost. Additionally, it makes the entire system portable, that is, display can be produced on any planar surface like floor, tabletop, and so on. The calibration and its performance have been evaluated by varying screen sizes and the number of points used for calibration. The device was successfully calibrated for different screens. A novel learning-based methodology for predicting a user’s behaviour was then realized to improve the system’s performance. This has been experimentally evaluated, and the overall accuracy of prediction was about 96%. An application was then designed for this set-up to improve the learning of alphabets by the children through an interactive audiovisual feedback system. It uses a game-based methodology to help students learn in a fun way. Currently, it has bilingual (Hindi and English user interface to enable learning of alphabets and elementary mathematics. A user survey was conducted after demonstrating it to school children. The survey results are very encouraging. Additionally, a study to ascertain the improvement in the learning outcome of the children was done. The results clearly indicate an improvement in the learning outcome of the children who used the device over those who did not.

  5. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    OpenAIRE

    Kovalenko, S.; Khoriauli, G.; C. Driouchi; J. D. Peso; L. Santi; Soloviev, I.; Arik, E.; Bernabeu, J; M. V. Castillo; Atkinson, T; Tegenfeldt, F.; Weidberg, A.R.; Røhne, O.; F. Anghinolfi; S. Chouridou

    2016-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Gea...

  6. State of the art review of radioactive waste volume reduction techniques for commercial nuclear power plants

    International Nuclear Information System (INIS)

    1980-04-01

    A review is made of the state of the art of volume reduction techniques for low level liquid and solid radioactive wastes produced as a result of: (1) operation of commercial nuclear power plants, (2) storage of spent fuel in away-from-reactor facilities, and (3) decontamination/decommissioning of commercial nuclear power plants. The types of wastes and their chemical, physical, and radiological characteristics are identified. Methods used by industry for processing radioactive wastes are reviewed and compared to the new techniques for processing and reducing the volume of radioactive wastes. A detailed system description and report on operating experiences follow for each of the new volume reduction techniques. In addition, descriptions of volume reduction methods presently under development are provided. The Appendix records data collected during site surveys of vendor facilities and operating power plants. A Bibliography is provided for each of the various volume reduction techniques discussed in the report

  7. Determination of the analytical performance of a headspace capillary gas chromatographic technique and karl Fischer coulometric titration by system calibration using oil samples containing known amounts of moisture.

    Science.gov (United States)

    Jalbert, J; Gilbert, R; Tétreault, P

    1999-08-01

    Over the past few years, concerns have been raised in the literature about the accuracy of the Karl Fischer (KF) method for assessing moisture in transformer mineral oils. To better understand this issue, the performance of a static headspace capillary gas chromatographic (HS-CGC) technique was compared to that of KF coulometric titration by analyzing moisture in samples containing known amounts of water and various samples obtained from the National Institute of Standards and Technology (NIST). Two modes of adding samples into the KF vessel were used:  direct injection and indirect injection via an azeotropic distillation of the moisture with toluene. Under the conditions used for direct injection, the oil matrix was totally dissolved in the anolyte, which allowed the moisture to be titrated in a single-phase solution rather than in a suspension. The results have shown that when HS-CGC and combined azeotropic distillation/KF titration are calibrated with moisture-in-oil standards, a linear relation is observed over 0-60 ppm H(2)O with a correlation coefficient better than 0.9994 (95% confidence), with the regression line crossing through zero. A similar relation can also be observed when calibration is achieved by direct KF addition of standards prepared with octanol-1, but in this case an intercept of 4-5 ppm is noted. The amount of moisture determined by curve interpolation in NIST reference materials by the three calibrated systems ranges from 13.0 to 14.8 ppm for RM 8506 and 42.5 to 46.4 ppm for RM 8507, and in any case, the results were as high as those reported in the literature with volumetric KF titration. However, titration of various dehydrated oil and solvent samples showed that direct KF titration is affected by a small bias when samples contain very little moisture. The source of error after correction for the large sample volume used for the determination (8 mL) is about 6 ppm for Voltesso naphthenic oil and 4 ppm for toluene, revealing a matrix

  8. Facilities and techniques for x-ray diagnostic calibration in the 100-eV to 100-keV energy range

    International Nuclear Information System (INIS)

    Gaines, J.L.; Wittmayer, F.J.

    1986-01-01

    The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. The authors built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses their calibration philosophy and techniques, and describes some of the x-ray sources. Examples of actual calibration data are presented as well

  9. Facilities and Techniques for X-Ray Diagnostic Calibration in the 100-eV to 100-keV Energy Range

    Science.gov (United States)

    Gaines, J. L.; Wittmayer, F. J.

    1986-08-01

    The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. We have built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses our calibration philosophy and techniques, and describes some of our x-ray sources. Examples of actual calibration data are presented as well.

  10. Facilities and techniques for x-ray diagnostic calibration in the 100-eV to 100-keV energy range

    International Nuclear Information System (INIS)

    Gaines, J.L.; Wittmayer, F.J.

    1986-06-01

    The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. We have built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses our calibration philosophy and techniques, and describes some of our x-ray sources. Examples of actual calibration data are presented as well

  11. Development, improvement and calibration of neutronic reaction rate measurements: elaboration of a base of standard techniques; Developpement, amelioration et calibration des mesures de taux de reaction neutroniques: elaboration d`une base de techniques standards

    Energy Technology Data Exchange (ETDEWEB)

    Hudelot, J.P

    1998-06-19

    In order to improve and to validate the neutronic calculation schemes, perfecting integral measurements of neutronic parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronic reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO{sub 2}) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of {sup 238}U (defined as the ratio of {sup 238}U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for {sup 242}Pu (on MOX rods) and

  12. A Synthesis of Star Calibration Techniques for Ground-Based Narrowband Electron-Multiplying Charge-Coupled Device Imagers Used in Auroral Photometry

    Science.gov (United States)

    Grubbs, Guy II; Michell, Robert; Samara, Marilia; Hampton, Don; Jahn, Jorg-Micha

    2016-01-01

    A technique is presented for the periodic and systematic calibration of ground-based optical imagers. It is important to have a common system of units (Rayleighs or photon flux) for cross comparison as well as self-comparison over time. With the advancement in technology, the sensitivity of these imagers has improved so that stars can be used for more precise calibration. Background subtraction, flat fielding, star mapping, and other common techniques are combined in deriving a calibration technique appropriate for a variety of ground-based imager installations. Spectral (4278, 5577, and 8446 A ) ground-based imager data with multiple fields of view (19, 47, and 180 deg) are processed and calibrated using the techniques developed. The calibration techniques applied result in intensity measurements in agreement between different imagers using identical spectral filtering, and the intensity at each wavelength observed is within the expected range of auroral measurements. The application of these star calibration techniques, which convert raw imager counts into units of photon flux, makes it possible to do quantitative photometry. The computed photon fluxes, in units of Rayleighs, can be used for the absolute photometry between instruments or as input parameters for auroral electron transport models.

  13. High volume fabrication of laser targets using MEMS techniques

    International Nuclear Information System (INIS)

    Spindloe, C; Tomlinson, S; Green, J; Booth, N.; Tolley, M K; Arthur, G; Hall, F; Potter, R; Kar, S; Higginbotham, A

    2016-01-01

    The latest techniques for the fabrication of high power laser targets, using processes developed for the manufacture of Micro-Electro-Mechanical System (MEMS) devices are discussed. These laser targets are designed to meet the needs of the increased shot numbers that are available in the latest design of laser facilities. Traditionally laser targets have been fabricated using conventional machining or coarse etching processes and have been produced in quantities of 10s to low 100s. Such targets can be used for high complexity experiments such as Inertial Fusion Energy (IFE) studies and can have many complex components that need assembling and characterisation with high precision. Using the techniques that are common to MEMS devices and integrating these with an existing target fabrication capability we are able to manufacture and deliver targets to these systems. It also enables us to manufacture novel targets that have not been possible using other techniques. In addition, developments in the positioning systems that are required to deliver these targets to the laser focus are also required and a system to deliver the target to a focus of an F2 beam at 0.1Hz is discussed. (paper)

  14. Application of the multisphere technique. Calibration and use of a modified Multiple Probe Detector

    International Nuclear Information System (INIS)

    Lalande, R.

    1966-11-01

    The study concerns the search for a portable, compact device with a great autonomy of operation, able to carry out precise measurements of fast neutrons in exclusion zones. A DSM-type multi-probe detector, which is self-contained and fully transistorized, have been studied; it includes a storage battery with a 30 hour autonomy and a buffering capability, a pulse amplifier, an integrator (sensitivity 4 c / s - 200 c / s - 2000 c / s), a totalizer to carry out counting on 5 mm, and a SNR fast neutron probe equipped with its preamplifier. Slightly modified, this device perfectly fulfills the operating conditions. Designed to precisely define the relationship between the flow and the dose intensity, it allows to calibrate any type of fast neutrons detector (e.g. BF 3 or unmodified DSM) that will respond correctly and will provide routine monitoring at a facility

  15. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    International Nuclear Information System (INIS)

    Abat, E; Arik, E; Abdallah, J M; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T P A; Aleksa, M; Anghinolfi, F; Baron, S; Alexa, C; Anderson, K; Andreazza, A; Banfi, D; Antonaki, A; Arabidze, G; Atkinson, T; Baines, J; Baker, O K

    2011-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  16. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    Energy Technology Data Exchange (ETDEWEB)

    Abat, E; Arik, E [Bogazici University, Faculty of Sciences, Department of Physics, TR - 80815 Bebek-Istanbul (Turkey); Abdallah, J M [Institut de Fisica d' Altes Energies, IFAE, Universitat Autonoma de Barcelona, Edifici Cn, ES - 08193 Bellaterra (Barcelona) Spain (Spain); Addy, T N [Hampton University, Department of Physics, Hampton, VA 23668 (United States); Adragna, P [Queen Mary, University of London, Mile End Road, E1 4NS, London (United Kingdom); Aharrouche, M [Universitaet Mainz, Institut fuer Physik, Staudinger Weg 7, DE 55099 (Germany); Ahmad, A [Insitute of Physics, Academia Sinica, TW - Taipei 11529, Taiwan (China); Akesson, T P A [Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Box 118, SE - 221 00, Lund (Sweden); Aleksa, M; Anghinolfi, F; Baron, S [European Laboratory for Particle Physics CERN, CH-1211 Geneva 23 (Switzerland); Alexa, C [National Institute of Physics and Nuclear Engineering (Bucharest -IFIN-HH), P.O. Box MG-6, R-077125 Bucharest (Romania); Anderson, K [University of Chicago, Enrico Fermi Institute, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Andreazza, A; Banfi, D [INFN Sezione di Milano, via Celoria 16, IT - 20133 Milano (Italy); Antonaki, A; Arabidze, G [University of Athens, Nuclear and Particle Physics Department of Physics, Panepistimiopouli Zografou, GR 15771 Athens (Greece); Atkinson, T [School of Physics, University of Melbourne, AU - Parkvill, Victoria 3010 (Australia); Baines, J [Rutherford Appleton Laboratory, Science and Technology Facilities Council, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom); Baker, O K, E-mail: kjg@particle.kth.se [Yale University, Department of Physics , PO Box 208121, New Haven, CT06520-8121 (United States)

    2011-06-15

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  17. Dynamic pressure sensor calibration techniques offering expanded bandwidth with increased resolution

    Science.gov (United States)

    Wisniewiski, David

    2015-03-01

    Advancements in the aerospace, defense and energy markets are being made possible by increasingly more sophisticated systems and sub-systems which rely upon critical information to be conveyed from the physical environment being monitored through ever more specialized, extreme environment sensing components. One sensing parameter of particular interest is dynamic pressure measurement. Crossing the boundary of all three markets (i.e. aerospace, defense and energy) is dynamic pressure sensing which is used in research and development of gas turbine technology, and subsequently embedded into a control loop used for long-term monitoring. Applications include quantifying the effects of aircraft boundary layer ingestion into the engine inlet to provide a reliable and robust design. Another application includes optimization of combustor dynamics by "listening" to the acoustic signature so that fuel-to-air mixture can be adjusted in real-time to provide cost operating efficiencies and reduced NOx emissions. With the vast majority of pressure sensors supplied today being calibrated either statically or "quasi" statically, the dynamic response characterization of the frequency dependent sensitivity (i.e. transfer function) of the pressure sensor is noticeably absent. The shock tube has been shown to be an efficient vehicle to provide frequency response of pressure sensors from extremely high frequencies down to 500 Hz. Recent development activity has lowered this starting frequency; thereby augmenting the calibration bandwidth with increased frequency resolution so that as the pressure sensor is used in an actual test application, more understanding of the physical measurement can be ascertained by the end-user.

  18. Fundamentals and techniques of nonimaging optics, volume 2

    Science.gov (United States)

    Winston, R.; Ogallagher, J. J.

    1983-06-01

    The formalism describing the operation is being defined, nonimaging concentrators and are being designed, and experiments and analytical studies are being conducted to evaluate the performance of new designs. In addition, components and materials particularly suited for use with these techniques were studied, and applications with an emphasis on solar energy concentration were explored. The motivation for the basic principles of nonimaging optics as they developed before 1978 are surveyed. The present status of the subdiscipline of nonimaging optics is summarized and an overview of the potential for future developments which is just beginning to emerge is presented.

  19. The technique of obtaining single-energy γ-rays in calibrating energy response of detector

    International Nuclear Information System (INIS)

    Li Rurong; Peng Taiping; Hu Mengchun; Li Zhongbao

    2004-01-01

    This paper introduces the principle of transforming γ-rays from 60 Co into a series of single-energy γ-rays and stresses the technique of shielding radiation-interfere and reducing energy-dispersion. The Single-energy γ-rays of any energy in the range of 0.36-1.02 MeV may be obtained by means of this technique. (authors)

  20. Sigmoid Colon Elongation Evaluation by Volume Rendering Technique

    Directory of Open Access Journals (Sweden)

    Atilla SENAYLI

    2011-06-01

    Full Text Available Sigmoid colons have various measurements, shapes, and configurations for individuals. In this subject there are rare clinical trials to answer the question of sigmoidal colon maldevelopment predicting a risk for volvulus. Therefore, sigmoid colon measurement may be beneficial to decide for volvulus. In a study, sigmoid colon diameters were evaluated during abdominal surgeries and it was found that median length was 47 cm and median vertical mesocolon length was 13 cm. We report a 14-year-old female patient who has a sigmoidal colon measured as nearly 54 cm. We used tomographic equipments for this evaluation. We know that MRI technique was used for this purpose but, there has not been data for MRI predicting the sigmoidal volvulus. We hope that our findings by this evaluation can contribute to insufficient literature of sigmoidal elongation. [J Contemp Med 2011; 1(2.000: 71-73

  1. A bronchoscopic navigation system using bronchoscope center calibration for accurate registration of electromagnetic tracker and CT volume without markers

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xiongbiao, E-mail: xiongbiao.luo@gmail.com [Robarts Research Institute, Western University, London, Ontario N6A 5K8 (Canada)

    2014-06-15

    Purpose: Various bronchoscopic navigation systems are developed for diagnosis, staging, and treatment of lung and bronchus cancers. To construct electromagnetically navigated bronchoscopy systems, registration of preoperative images and an electromagnetic tracker must be performed. This paper proposes a new marker-free registration method, which uses the centerlines of the bronchial tree and the center of a bronchoscope tip where an electromagnetic sensor is attached, to align preoperative images and electromagnetic tracker systems. Methods: The chest computed tomography (CT) volume (preoperative images) was segmented to extract the bronchial centerlines. An electromagnetic sensor was fixed at the bronchoscope tip surface. A model was designed and printed using a 3D printer to calibrate the relationship between the fixed sensor and the bronchoscope tip center. For each sensor measurement that includes sensor position and orientation information, its corresponding bronchoscope tip center position was calculated. By minimizing the distance between each bronchoscope tip center position and the bronchial centerlines, the spatial alignment of the electromagnetic tracker system and the CT volume was determined. After obtaining the spatial alignment, an electromagnetic navigation bronchoscopy system was established to real-timely track or locate a bronchoscope inside the bronchial tree during bronchoscopic examinations. Results: The electromagnetic navigation bronchoscopy system was validated on a dynamic bronchial phantom that can simulate respiratory motion with a breath rate range of 0–10 min{sup −1}. The fiducial and target registration errors of this navigation system were evaluated. The average fiducial registration error was reduced from 8.7 to 6.6 mm. The average target registration error, which indicates all tracked or navigated bronchoscope position accuracy, was much reduced from 6.8 to 4.5 mm compared to previous registration methods. Conclusions: An

  2. A bronchoscopic navigation system using bronchoscope center calibration for accurate registration of electromagnetic tracker and CT volume without markers

    International Nuclear Information System (INIS)

    Luo, Xiongbiao

    2014-01-01

    Purpose: Various bronchoscopic navigation systems are developed for diagnosis, staging, and treatment of lung and bronchus cancers. To construct electromagnetically navigated bronchoscopy systems, registration of preoperative images and an electromagnetic tracker must be performed. This paper proposes a new marker-free registration method, which uses the centerlines of the bronchial tree and the center of a bronchoscope tip where an electromagnetic sensor is attached, to align preoperative images and electromagnetic tracker systems. Methods: The chest computed tomography (CT) volume (preoperative images) was segmented to extract the bronchial centerlines. An electromagnetic sensor was fixed at the bronchoscope tip surface. A model was designed and printed using a 3D printer to calibrate the relationship between the fixed sensor and the bronchoscope tip center. For each sensor measurement that includes sensor position and orientation information, its corresponding bronchoscope tip center position was calculated. By minimizing the distance between each bronchoscope tip center position and the bronchial centerlines, the spatial alignment of the electromagnetic tracker system and the CT volume was determined. After obtaining the spatial alignment, an electromagnetic navigation bronchoscopy system was established to real-timely track or locate a bronchoscope inside the bronchial tree during bronchoscopic examinations. Results: The electromagnetic navigation bronchoscopy system was validated on a dynamic bronchial phantom that can simulate respiratory motion with a breath rate range of 0–10 min −1 . The fiducial and target registration errors of this navigation system were evaluated. The average fiducial registration error was reduced from 8.7 to 6.6 mm. The average target registration error, which indicates all tracked or navigated bronchoscope position accuracy, was much reduced from 6.8 to 4.5 mm compared to previous registration methods. Conclusions: An

  3. Calibration of the JET neutron yield monitors using the delayed neutron counting technique

    International Nuclear Information System (INIS)

    van Belle, P.; Jarvis, O.N.; Sadler, G.; de Leeuw, S.; D'Hondt, P.; Pillon, M.

    1990-01-01

    The time-resolved neutron yield is routinely measured on the JET tokamak using a set of fission chambers. At present, the preferred technique is to employ activation reactions to determine the neutron fluence at a well-chosen position and to relate the measured fluence to the total neutron emission by means of neutron transport calculations. The delayed neutron counting method is a particularly convenient method of performing the activation measurement and the fission cross sections are accurately known. This paper outlines the measurement technique as used on JET

  4. Soot volume fraction fields in unsteady axis-symmetric flames by continuous laser extinction technique.

    Science.gov (United States)

    Kashif, Muhammad; Bonnety, Jérôme; Guibert, Philippe; Morin, Céline; Legros, Guillaume

    2012-12-17

    A Laser Extinction Method has been set up to provide two-dimensional soot volume fraction field time history at a tunable frequency up to 70 Hz inside an axis-symmetric diffusion flame experiencing slow unsteady phenomena preserving the symmetry. The use of a continuous wave laser as the light source enables this repetition rate, which is an incremental advance in the laser extinction technique. The technique is shown to allow a fine description of the soot volume fraction field in a flickering flame exhibiting a 12.6 Hz flickering phenomenon. Within this range of repetition rate, the technique and its subsequent post-processing require neither any method for time-domain reconstruction nor any correction for energy intrusion. Possibly complemented by such a reconstruction method, the technique should support further soot volume fraction database in oscillating flames that exhibit characteristic times relevant to the current efforts in the validation of soot processes modeling.

  5. A Two-Step A/D Conversion and Column Self-Calibration Technique for Low Noise CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Jaeyoung Bae

    2014-07-01

    Full Text Available In this paper, a 120 frames per second (fps low noise CMOS Image Sensor (CIS based on a Two-Step Single Slope ADC (TS SS ADC and column self-calibration technique is proposed. The TS SS ADC is suitable for high speed video systems because its conversion speed is much faster (by more than 10 times than that of the Single Slope ADC (SS ADC. However, there exist some mismatching errors between the coarse block and the fine block due to the 2-step operation of the TS SS ADC. In general, this makes it difficult to implement the TS SS ADC beyond a 10-bit resolution. In order to improve such errors, a new 4-input comparator is discussed and a high resolution TS SS ADC is proposed. Further, a feedback circuit that enables column self-calibration to reduce the Fixed Pattern Noise (FPN is also described. The proposed chip has been fabricated with 0.13 μm Samsung CIS technology and the chip satisfies the VGA resolution. The pixel is based on the 4-TR Active Pixel Sensor (APS. The high frame rate of 120 fps is achieved at the VGA resolution. The measured FPN is 0.38 LSB, and measured dynamic range is about 64.6 dB.

  6. A 72-dB-SNDR rail-to-rail successive approximation ADC using mismatch calibration techniques

    International Nuclear Information System (INIS)

    Liu Yan; Hua Siliang; Wang Donghui; Hou Chaohuan

    2012-01-01

    When the voltage of an analog input signal is equal to the supply voltage, it is difficult for a conventional successive approximation ADC to correctly convert the analog signal into digital signal. This paper introduces an improved successive approximation ADC, which can convert the rail-to-rail input range and reduce sampling time through a track-and-hold circuit. Comparator offset cancellation and capacitor self-calibration techniques are used in this ADC. Measurement results show that the peak SNDR of this ADC reaches 72 dB and the signal effective bandwidth is up to 1.25 MHz. It consumes 1 mW in the test, and the figure of merit is 123 fJ/conversion-step. (semiconductor integrated circuits)

  7. A fitting algorithm based on simulated annealing techniques for efficiency calibration of HPGe detectors using different mathematical functions

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado, S. [Servicio de Radioisotopos, Centro de Investigacion, Tecnologia e Innovacion (CITIUS), Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain)], E-mail: shurtado@us.es; Garcia-Leon, M. [Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Fisica, Universidad de Sevilla, Aptd. 1065, 41080 Sevilla (Spain); Garcia-Tenorio, R. [Departamento de Fisica Aplicada II, E.T.S.A. Universidad de Sevilla, Avda, Reina Mercedes 2, 41012 Sevilla (Spain)

    2008-09-11

    In this work several mathematical functions are compared in order to perform the full-energy peak efficiency calibration of HPGe detectors using a 126cm{sup 3} HPGe coaxial detector and gamma-ray energies ranging from 36 to 1460 keV. Statistical tests and Monte Carlo simulations were used to study the performance of the fitting curve equations. Furthermore the fitting procedure of these complex functional forms to experimental data is a non-linear multi-parameter minimization problem. In gamma-ray spectrometry usually non-linear least-squares fitting algorithms (Levenberg-Marquardt method) provide a fast convergence while minimizing {chi}{sub R}{sup 2}, however, sometimes reaching only local minima. In order to overcome that shortcoming a hybrid algorithm based on simulated annealing (HSA) techniques is proposed. Additionally a new function is suggested that models the efficiency curve of germanium detectors in gamma-ray spectrometry.

  8. Application of OLM Techniques to Enhance the Calibration and Maintenance Practices In ESSalam Nuclear Research Reactor

    International Nuclear Information System (INIS)

    Touati, S.; Messai, A.; Abdellani, I.

    2013-06-01

    As a beginning, we consider the case of the coolant pumps (electrical motor and a driven pump) which are critical part in all nuclear facility and are an element in safety processes requiring highest reliability condition monitoring. In order to determine their operational characteristics, degradation mechanisms, and failure modes, we will use some on-line acquired parameters such as: the vibration data collection, temperature measurement, ...etc. Through adequate analysis, including artificial intelligence techniques and frequency analysis, performed on-line on these recorded data, we will be able to establish a predictive maintenance program for crucial rotating equipment in our research reactor. (authors)

  9. Particle identification at LHCb: new calibration techniques and machine learning classification algorithms

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Particle identification (PID) plays a crucial role in LHCb analyses. Combining information from LHCb subdetectors allows one to distinguish between various species of long-lived charged and neutral particles. PID performance directly affects the sensitivity of most LHCb measurements. Advanced multivariate approaches are used at LHCb to obtain the best PID performance and control systematic uncertainties. This talk highlights recent developments in PID that use innovative machine learning techniques, as well as novel data-driven approaches which ensure that PID performance is well reproduced in simulation.

  10. Using artificial soil sediment mixtures for calibrating fingerprinting techniques at catchment scale

    International Nuclear Information System (INIS)

    Torres Astorga, Romina; Martin, Osvaldo A.; Velasco, Ricardo Hugo; Santos-Villalobos, Sergio de los; Mabit, Lionel; Dercon, Gerd

    2016-01-01

    Soil erosion and related sediment transportation and deposition are key environmental problems in Central Argentina. Certain land use practices, such as intensive grazing, are considered particularly harmful in causing erosion and sediment mobilization. In our studied catchment, Sub Catchment Estancia Grande (630 hectares), 23 km north east from San Luis, characterized by erosive loess soils, we tested sediment source fingerprinting techniques to identify critical hot spots of land degradation, based on the concentration of 43 elements determined by Energy Dispersive X Ray Fluorescence (EDXRF).

  11. Advanced Ecosystem Mapping Techniques for Large Arctic Study Domains Using Calibrated High-Resolution Imagery

    Science.gov (United States)

    Macander, M. J.; Frost, G. V., Jr.

    2015-12-01

    Regional-scale mapping of vegetation and other ecosystem properties has traditionally relied on medium-resolution remote sensing such as Landsat (30 m) and MODIS (250 m). Yet, the burgeoning availability of high-resolution (environments has not been previously evaluated. Image segmentation, or object-based image analysis, automatically partitions high-resolution imagery into homogeneous image regions that can then be analyzed based on spectral, textural, and contextual information. We applied eCognition software to delineate waterbodies and vegetation classes, in combination with other techniques. Texture metrics were evaluated to determine the feasibility of using high-resolution imagery to algorithmically characterize periglacial surface forms (e.g., ice-wedge polygons), which are an important physical characteristic of permafrost-dominated regions but which cannot be distinguished by medium-resolution remote sensing. These advanced mapping techniques provide products which can provide essential information supporting a broad range of ecosystem science and land-use planning applications in northern Alaska and elsewhere in the circumpolar Arctic.

  12. Measurement of liver and spleen volume by computed tomography using point counting technique

    International Nuclear Information System (INIS)

    Matsuda, Yoshiro; Sato, Hiroyuki; Nei, Jinichi; Takada, Akira

    1982-01-01

    We devised a new method for measurement of liver and spleen volume by computed tomography using point counting technique. This method is very simple and applicable to any kind of CT scanner. The volumes of the livers and spleens estimated by this method were significantly correlated with the weights of the corresponding organs measured on autopsy or surgical operation, indicating clinical usefulness of this method. Hepatic and splenic volumes were estimated by this method in 43 patients with chronic liver disease and 9 subjects with non-hepatobiliary disease. The mean hepatic volume in non-alcoholic liver cirrhosis was significantly smaller than those in non-hepatobiliary disease and other chronic liver diseases. The mean hepatic volume in alcoholic cirrhosis and alcoholic fibrosis tended to be slightly larger than that in non-hepatobiliary disease. The mean splenic volume in liver cirrhosis was significantly larger than those in non-hepatobiliary disease and other chronic liver diseases. However, there was no significant difference of the mean splenic volume between alcoholic and non-alcoholic cirrhosis. Significantly positive correlation between hepatic and splenic volumes was found in alcoholic cirrhosis, but not in non-alcoholic cirrhosis. These results indicate that estimation of hepatic and splenic volumes by this method is useful for the analysis of the pathophysiological condition of chronic liver diseases. (author)

  13. Principles and techniques of radiation hardening. Volume 2. Transient radiation effects in electronics (TREE)

    International Nuclear Information System (INIS)

    Rudie, N.J.

    1976-01-01

    The three-volume book is intended to serve as a review of the effects of thermonuclear explosion induced radiation (x-rays, gamma rays, and beta particles) and the resulting electromagnetic pulse (EMP). Volume 2 deals with the following topics: radiation effects on quartz crystals, tantalum capacitors, bipolar semiconductor devices and integrated circuits, field effect transistors, and miscellaneous electronic devices; hardening electronic systems to photon and neutron radiation; nuclear radiation source and/or effects simulation techniques; and radiation dosimetry

  14. Determining carotid artery pressure from scaled diameter waveforms: comparison and validation of calibration techniques in 2026 subjects

    International Nuclear Information System (INIS)

    Vermeersch, S J; Verdonck, P R; Segers, P; Rietzschel, E R; De Buyzere, M L; Gillebert, T C; De Bacquer, D; De Backer, G; Van Bortel, L M

    2008-01-01

    Calibrated diameter distension waveforms could provide an alternative for local arterial pressure assessment more widely applicable than applanation tonometry. We compared linearly and exponentially calibrated carotid diameter waveforms to tonometry readings. Local carotid pressures measured by tonometry and diameter waveforms measured by ultrasound were obtained in 2026 subjects participating in the Asklepios study protocol. Diameter waveforms were calibrated using a linear and an exponential calibration scheme and compared to measured tonometry waveforms by examining the mean root-mean-squared error (RMSE), carotid systolic blood pressure (SBP car ) and augmentation index (AIx) of calibrated and measured pressures. Mean RMSE was 5.2(3.3) mmHg (mean(stdev)) for linear and 4.6(3.6) mmHg for exponential calibration. Linear calibration yielded an underestimation of SBP car by 6.4(4.1) mmHg which was strongly correlated to values of brachial pulse pressure (PP bra ) (R = 0.4, P car by 1.9(3.9) mmHg, independent of PP bra . AIx was overestimated by linear calibration by 1.9(10.1)%, the difference significantly increasing with increasing AIx (R = 0.25, P < 0.001) and by exponential calibration by 5.4(10.6)%, independently of the value of AIx. Properly calibrated diameter waveforms offer a viable alternative for local pressure estimation at the carotid artery. Compared to linear calibration, exponential calibration significantly improves the pressure estimation

  15. A digital calibration technique for an ultra high-speed wide-bandwidth folding and interpolating analog-to-digital converter in 0.18-{mu}m CMOS technology

    Energy Technology Data Exchange (ETDEWEB)

    Yu Jinshan; Zhang Ruitao; Zhang Zhengping; Wang Yonglu; Zhu Can; Zhang Lei; Yu Zhou; Han Yong, E-mail: yujinshan@yeah.net [National Laboratory of Analog IC' s, Chongqing 400060 (China)

    2011-01-15

    A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital converter in 0.18-{mu}m CMOS technology is presented. The similar digital calibration techniques are taken for high 3-bit flash converter and low 5-bit folding and interpolating converter, which are based on well-designed calibration reference, calibration DAC and comparators. The spice simulation and the measured results show the ADC produces 5.9 ENOB with calibration disabled and 7.2 ENOB with calibration enabled for high-frequency wide-bandwidth analog input. (semiconductor integrated circuits)

  16. Refining Soil Test Calibration and Nitrogen Recommendation in Corn through 15N Isotope Tracer Technique

    International Nuclear Information System (INIS)

    Rallos, Roland V.

    2015-01-01

    Soil test serve as a baseline to efficiently manage the fertilizer inputs and determine excess nutrients that may cause adverse impact to human health and the environment. The ever increasing fertilizer prices and application inefficiency raised concerns to re-evaluate and redesigned the current crop cultural management to increase its efficiency and productivity. Additionally, with the intensification of farming methods, corn varietal improvement, soil degradations, climate change among many others, the earlier fertilizer recommendations may not be sufficient enough to match with the crop’s fertilizer requirements. The use of 15N isotope tracer techniques in nutrient management research implies important benefits than any existing conventional methodologies. This technology provides enormous advantages because it permits a direct quantitative measurement of the crop nutrient utilization under the influence of varied factors of the environment. Hence, this technique was used to understand N dynamics and fertilizer N-use efficiency (FNUE) in corn grown under different soil fertility levels during wet and dry season productions. This allows us to follow the fate and accurately quantify the contribution of different N pools to the crops N nutrition. Results showed that the fertilizer rates for optimum corn yield under low soil N was observed at 180 kg N ha-1 during dry season while 90 kg N ha-1 during wet season production. While for medium and high N soil, the optimum production yield was noted in 45 kg N ha-1 both in dry and wet season productions. Economic optimum nitrogen recommendations (EONR) were also calculated following the quadratic crop response model. In all cases, EONR for dry season productions are much higher compared to wet season production. Generally, high chlorophyll content was observed at higher fertilizer levels. In addition, more than half of the plant N was taken directly from the added fertilizer during the early stage (30-60 days after

  17. Near Infrared Spectroscopy Calibration for Wood Chemistry: Which Chemometric Technique Is Best for Prediction and Interpretation?

    Directory of Open Access Journals (Sweden)

    Brian K. Via

    2014-07-01

    Full Text Available This paper addresses the precision in factor loadings during partial least squares (PLS and principal components regression (PCR of wood chemistry content from near infrared reflectance (NIR spectra. The precision of the loadings is considered important because these estimates are often utilized to interpret chemometric models or selection of meaningful wavenumbers. Standard laboratory chemistry methods were employed on a mixed genus/species hardwood sample set. PLS and PCR, before and after 1st derivative pretreatment, was utilized for model building and loadings investigation. As demonstrated by others, PLS was found to provide better predictive diagnostics. However, PCR exhibited a more precise estimate of loading peaks which makes PCR better for interpretation. Application of the 1st derivative appeared to assist in improving both PCR and PLS loading precision, but due to the small sample size, the two chemometric methods could not be compared statistically. This work is important because to date most research works have committed to PLS because it yields better predictive performance. But this research suggests there is a tradeoff between better prediction and model interpretation. Future work is needed to compare PLS and PCR for a suite of spectral pretreatment techniques.

  18. Near infrared spectroscopy calibration for wood chemistry: which chemometric technique is best for prediction and interpretation?

    Science.gov (United States)

    Via, Brian K; Zhou, Chengfeng; Acquah, Gifty; Jiang, Wei; Eckhardt, Lori

    2014-07-25

    This paper addresses the precision in factor loadings during partial least squares (PLS) and principal components regression (PCR) of wood chemistry content from near infrared reflectance (NIR) spectra. The precision of the loadings is considered important because these estimates are often utilized to interpret chemometric models or selection of meaningful wavenumbers. Standard laboratory chemistry methods were employed on a mixed genus/species hardwood sample set. PLS and PCR, before and after 1st derivative pretreatment, was utilized for model building and loadings investigation. As demonstrated by others, PLS was found to provide better predictive diagnostics. However, PCR exhibited a more precise estimate of loading peaks which makes PCR better for interpretation. Application of the 1st derivative appeared to assist in improving both PCR and PLS loading precision, but due to the small sample size, the two chemometric methods could not be compared statistically. This work is important because to date most research works have committed to PLS because it yields better predictive performance. But this research suggests there is a tradeoff between better prediction and model interpretation. Future work is needed to compare PLS and PCR for a suite of spectral pretreatment techniques.

  19. Improved calibration technique for in vivo proton MRS thermometry for brain temperature measurement.

    Science.gov (United States)

    Zhu, M; Bashir, A; Ackerman, J J; Yablonskiy, D A

    2008-09-01

    The most common MR-based approach to noninvasively measure brain temperature relies on the linear relationship between the (1)H MR resonance frequency of tissue water and the tissue's temperature. Herein we provide the most accurate in vivo assessment existing thus far of such a relationship. It was derived by acquiring in vivo MR spectra from a rat brain using a high field (11.74 Tesla [T]) MRI scanner and a single-voxel MR spectroscopy technique based on a LASER pulse sequence. Data were analyzed using three different methods to estimate the (1)H resonance frequencies of water and the metabolites NAA, Cho, and Cr, which are used as temperature-independent internal (frequency) references. Standard modeling of frequency-domain data as composed of resonances characterized by Lorentzian line shapes gave the tightest resonance-frequency versus temperature correlation. An analysis of the uncertainty in temperature estimation has shown that the major limiting factor is an error in estimating the metabolite frequency. For example, for a metabolite resonance linewidth of 8 Hz, signal sampling rate of 2 Hz and SNR of 5, an accuracy of approximately 0.5 degrees C can be achieved at a magnetic field of 3T. For comparison, in the current study conducted at 11.74T, the temperature estimation error was approximately 0.1 degrees C.

  20. Calibrated delivery drape versus indirect gravimetric technique for the measurement of blood loss after delivery: a randomized trial.

    Science.gov (United States)

    Ambardekar, Shubha; Shochet, Tara; Bracken, Hillary; Coyaji, Kurus; Winikoff, Beverly

    2014-08-15

    Trials of interventions for PPH prevention and treatment rely on different measurement methods for the quantification of blood loss and identification of PPH. This study's objective was to compare measures of blood loss obtained from two different measurement protocols frequently used in studies. Nine hundred women presenting for vaginal delivery were randomized to a direct method (a calibrated delivery drape) or an indirect method (a shallow bedpan placed below the buttocks and weighing the collected blood and blood-soaked gauze/pads). Blood loss was measured from immediately after delivery for at least one hour or until active bleeding stopped. Significantly greater mean blood loss was recorded by the direct than by the indirect measurement technique (253.9 mL and 195.3 mL, respectively; difference = 58.6 mL (95% CI: 31-86); p 500 mL (8.7% vs. 4.7%, p = 0.02). The study suggests a real and significant difference in blood loss measurement between these methods. Research using blood loss measurement as an endpoint needs to be interpreted taking measurement technique into consideration. This study has been registered at clinicaltrials.gov as NCT01885845.

  1. Estimation of Apple Volume and Its Shape Indentation Using Image Processing Technique and Neural Network

    Directory of Open Access Journals (Sweden)

    M Jafarlou

    2014-04-01

    Full Text Available Physical properties of agricultural products such as volume are the most important parameters influencing grading and packaging systems. They should be measured accurately as they are considered for any good system design. Image processing and neural network techniques are both non-destructive and useful methods which are recently used for such purpose. In this study, the images of apples were captured from a constant distance and then were processed in MATLAB software and the edges of apple images were extracted. The interior area of apple image was divided into some thin trapezoidal elements perpendicular to longitudinal axis. Total volume of apple was estimated by the summation of incremental volumes of these elements revolved around the apple’s longitudinal axis. The picture of half cut apple was also captured in order to obtain the apple shape’s indentation volume, which was subtracted from the previously estimated total volume of apple. The real volume of apples was measured using water displacement method and the relation between the real volume and estimated volume was obtained. The t-test and Bland-Altman indicated that the difference between the real volume and the estimated volume was not significantly different (p>0.05 i.e. the mean difference was 1.52 cm3 and the accuracy of measurement was 92%. Utilizing neural network with input variables of dimension and mass has increased the accuracy up to 97% and the difference between the mean of volumes decreased to 0.7 cm3.

  2. Errors during MRT measurements of the left ventricular volume using a multi-slice technique

    International Nuclear Information System (INIS)

    Pitton, M.B.; Just, M.; Grebe, P.; Kreitner, K.F.; Erbel, R.; Thelen, M.

    1992-01-01

    A multi-slice technique for MRT measurements of the left ventricular volume is much faster than the use of single-slice methods and is therefore better tolerated, leaving time for additional measurements. The end-diastolic left ventricular volume can be reliably measured by this method (123.3±13.5 ml vs. 124.1±ml). The end-systolic volume is consistently overestimated by 23.7±18,3% compared with the reference value obtained by single slice measurements (47.9±8.9 ml vs 39.1±7.9 ml). Correspondingly, stroke volume and ejection fraction is underestimated on average by 10.6±9.7% and 10.6±7.6% respectively). (orig.) [de

  3. Nuclear assay of coal. Volume 4. Moisture determination in coal: survey of electromagnetic techniques. Final report

    International Nuclear Information System (INIS)

    Bevan, R.; Luckie, P.; Gozani, T.; Brown, D.R.; Bozorgmanesh, H.; Elias, E.

    1979-01-01

    This survey consists of two basic parts. The first consists of a survey of various non-nuclear moisture determination techniques. Three techniques are identified as promising for eventual on-line application with coal; these are the capacitance, microwave attenuation, and nuclear magnetic resonance (NMR) techniques. The second part is devoted to an in-depth analysis of these three techniques and the current extent to which they have been applied to coal. With a given coal type, accuracies of +- 1% absolute in moisture content are achievable with all three techniques. The accuracy of the two electromagnetic techniques has been demonstrated in the laboratory and on-line in coal burning plants, whereas only small samples have been analyzed with NMR. The current shortcoming of the simple electromagnetic techniques is the sensitivity of calibrations to physical parameters and coal type. NMR is currently limited by small sample sizes and non-rugged design. These findings are summarized and a list of manufacturers of moisture analyzers is given in the Appendix

  4. Construction of calibration curve for accountancy tank

    International Nuclear Information System (INIS)

    Kato, Takayuki; Goto, Yoshiki; Nidaira, Kazuo

    2009-01-01

    Tanks are equipped in a reprocessing plant for accounting solution of nuclear material. The careful measurement of volume in tanks is very important to implement rigorous accounting of nuclear material. The calibration curve relating the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes. Several calibration curves are usually employed, but it's not explicitly decided how many segment are used, where to select segment, or what should be the degree of polynomial curve. These parameters, i.e., segment and degree of polynomial curve are mutually interrelated to give the better performance of calibration curve. Here we present the construction technique of giving optimum calibration curves and their characteristics. (author)

  5. The rationale and technique of staged-volume arteriovenous malformation radiosurgery

    International Nuclear Information System (INIS)

    Pollock, Bruce E.; Kline, Robert W.; Stafford, Scott L.; Foote, Robert L.; Schomberg, Paula J.

    2000-01-01

    Purpose: Stereotactic radiosurgery is an effective management strategy for properly selected arteriovenous malformation (AVM) patients. However, the risk of postradiosurgical radiation-related injury generally limits this procedure to patients with AVMs of an average diameter of 3 cm or less. Radiosurgery of large AVMs in a planned staged fashion was undertaken to limit the radiation exposure to the surrounding normal brain. Methods and Materials: Between April 1997 and December 1999, 10 patients with a median AVM volume of 17.4 cm 3 (range, 7.4-53.3 cm 3 ) underwent staged-volume radiosurgery (23 procedures). At the first radiosurgical procedure, the total volume of the AVM is estimated and a dose plan calculated that covers 10 cm 3 -15 cm 3 , or one-half the nidus volume if the AVM is critically located (brainstem, thalamus, or basal ganglia). At 6-month intervals thereafter, radiosurgery was repeated to different portions of the AVM with the previous dose plan(s) being re-created utilizing intracranial landmarks to minimize radiation overlap. Radiosurgical procedures were continued until the entire malformation has been irradiated. Results: The radiation dosimetry of staged-volume AVM radiosurgery was compared to hypothetical single-session procedures for the 10 patients. Staged-volume radiosurgery decreased the 12-Gy volume by an average of 11.1% (range, 4.9-21%) (p < 0.001). The non-AVM 12-Gy volume was reduced by an average of 27.2% (range, 12.5-51.3%) (p < 0.001). Discussion: Staged-volume radiosurgery of large AVMs results in less radiation exposure to the adjacent brain. Further follow-up is needed to determine whether this technique provides a high rate of AVM obliteration while maintaining an acceptable rate of radiation-related complications

  6. Reassessment of the NH4 NO3 thermal decomposition technique for calibration of the N2 O isotopic composition.

    Science.gov (United States)

    Mohn, Joachim; Gutjahr, Wilhelm; Toyoda, Sakae; Harris, Eliza; Ibraim, Erkan; Geilmann, Heike; Schleppi, Patrick; Kuhn, Thomas; Lehmann, Moritz F; Decock, Charlotte; Werner, Roland A; Yoshida, Naohiro; Brand, Willi A

    2016-09-08

    In the last few years, the study of N 2 O site-specific nitrogen isotope composition has been established as a powerful technique to disentangle N 2 O emission pathways. This trend has been accelerated by significant analytical progress in the field of isotope-ratio mass-spectrometry (IRMS) and more recently quantum cascade laser absorption spectroscopy (QCLAS). Methods The ammonium nitrate (NH 4 NO 3 ) decomposition technique provides a strategy to scale the 15 N site-specific (SP ≡ δ 15 N α - δ 15 N β ) and bulk (δ 15 N bulk  = (δ 15 N α  + δ 15 N β )/2) isotopic composition of N 2 O against the international standard for the 15 N/ 14 N isotope ratio (AIR-N 2 ). Within the current project 15 N fractionation effects during thermal decomposition of NH 4 NO 3 on the N 2 O site preference were studied using static and dynamic decomposition techniques. The validity of the NH 4 NO 3 decomposition technique to link NH 4 + and NO 3 - moiety-specific δ 15 N analysis by IRMS to the site-specific nitrogen isotopic composition of N 2 O was confirmed. However, the accuracy of this approach for the calibration of δ 15 N α and δ 15 N β values was found to be limited by non-quantitative NH 4 NO 3 decomposition in combination with substantially different isotope enrichment factors for the conversion of the NO 3 - or NH 4 + nitrogen atom into the α or β position of the N 2 O molecule. The study reveals that the completeness and reproducibility of the NH 4 NO 3 decomposition reaction currently confine the anchoring of N 2 O site-specific isotopic composition to the international isotope ratio scale AIR-N 2 . The authors suggest establishing a set of N 2 O isotope reference materials with appropriate site-specific isotopic composition, as community standards, to improve inter-laboratory compatibility. This article is protected by copyright. All rights reserved.

  7. Calibration of the maximum carboxylation velocity (Vcmax using data mining techniques and ecophysiological data from the Brazilian semiarid region, for use in Dynamic Global Vegetation Models

    Directory of Open Access Journals (Sweden)

    L. F. C. Rezende

    Full Text Available Abstract The semiarid region of northeastern Brazil, the Caatinga, is extremely important due to its biodiversity and endemism. Measurements of plant physiology are crucial to the calibration of Dynamic Global Vegetation Models (DGVMs that are currently used to simulate the responses of vegetation in face of global changes. In a field work realized in an area of preserved Caatinga forest located in Petrolina, Pernambuco, measurements of carbon assimilation (in response to light and CO2 were performed on 11 individuals of Poincianella microphylla, a native species that is abundant in this region. These data were used to calibrate the maximum carboxylation velocity (Vcmax used in the INLAND model. The calibration techniques used were Multiple Linear Regression (MLR, and data mining techniques as the Classification And Regression Tree (CART and K-MEANS. The results were compared to the UNCALIBRATED model. It was found that simulated Gross Primary Productivity (GPP reached 72% of observed GPP when using the calibrated Vcmax values, whereas the UNCALIBRATED approach accounted for 42% of observed GPP. Thus, this work shows the benefits of calibrating DGVMs using field ecophysiological measurements, especially in areas where field data is scarce or non-existent, such as in the Caatinga.

  8. Impact of robotic technique and surgical volume on the cost of radical prostatectomy.

    Science.gov (United States)

    Hyams, Elias S; Mullins, Jeffrey K; Pierorazio, Phillip M; Partin, Alan W; Allaf, Mohamad E; Matlaga, Brian R

    2013-03-01

    Our present understanding of the effect of robotic surgery and surgical volume on the cost of radical prostatectomy (RP) is limited. Given the increasing pressures placed on healthcare resource utilization, such determinations of healthcare value are becoming increasingly important. Therefore, we performed a study to define the effect of robotic technology and surgical volume on the cost of RP. The state of Maryland mandates that all acute-care hospitals report encounter-level and hospital discharge data to the Health Service Cost Review Commission (HSCRC). The HSCRC was queried for men undergoing RP between 2008 and 2011 (the period during which robot-assisted laparoscopic radical prostatectomy [RALRP] was coded separately). High-volume hospitals were defined as >60 cases per year, and high-volume surgeons were defined as >40 cases per year. Multivariate regression analysis was performed to evaluate whether robotic technique and high surgical volume impacted the cost of RP. There were 1499 patients who underwent RALRP and 2565 who underwent radical retropubic prostatectomy (RRP) during the study period. The total cost for RALRP was higher than for RRP ($14,000 vs 10,100; Probotic surgery has come to dominate the healthcare marketplace, strategies to increase the role of high-volume providers may be needed to improve the cost-effectiveness of prostate cancer surgical therapy.

  9. MoDOT pavement preservation research program volume VII, re-calibration of triggers and performance models.

    Science.gov (United States)

    2015-10-01

    The objective of this task is to develop the concept and framework for a procedure to routinely create, re-calibrate, and update the : Trigger Tables and Performance Models. The scope of work for Task 6 includes a limited review of the recent pavemen...

  10. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 6: Accurate in-tank determination of liquid density in accountancy tanks equipped with dip tubes

    International Nuclear Information System (INIS)

    2008-01-01

    ISO 18213 deals with the acquisition, standardization, analysis, and use of calibration data to determine liquid volumes in process tanks for accountability purposes. This part of ISO 18213 is complementary to the other parts, ISO 18213-1 (procedural overview), ISO 18213-2 (data standardization), ISO 18213-3 (statistical methods), ISO 18213-4 (slow bubbling rate), ISO 18213-5 (fast bubbling rate). The procedure described in this part of ISO 18213 is a two-step procedure. First, a liquid of known density is used to determine the vertical distance between the tips of the two probes (i.e. to calibrate their separation). The calibration step requires synchronous (or as nearly synchronous as possible) measurements of the pressure exerted at the tips of two probes by the calibration liquid in which they are submerged. The measurements obtained are used to make an accurate determination of probe separation. Second, the unknown density of the process liquid is determined with the aid of the probe separation calibration. The density-determination step also requires (nearly) synchronous measurements of the pressure exerted at the tips of two probes by the process liquid of unknown density. With careful technique, it is possible to make determinations of liquid density with in-tank measurements that approach the accuracy and precision of those made in the laboratory. Moreover, density determinations made with in-tank measurements are automatically made at the observed temperature of the tank liquid. Thus, no additional information about the liquid is required to infer its density at its tank temperature from determinations of its density at some other temperature. Except that the density of the process liquid is generally not well characterized, the steps involved in determining the height of process liquid in the tank are the same as those for determining the height of calibration liquid. Thus, the method of density determination given in this part of ISO 18213 is very

  11. Development of rapid, continuous calibration techniques and implementation as a prototype system for civil engineering materials evaluation

    International Nuclear Information System (INIS)

    Scott, M. L.; Gagarin, N.; Mekemson, J. R.; Chintakunta, S. R.

    2011-01-01

    Until recently, civil engineering material calibration data could only be obtained from material sample cores or via time consuming, stationary calibration measurements in a limited number of locations. Calibration data are used to determine material propagation velocities of electromagnetic waves in test materials for use in layer thickness measurements and subsurface imaging. Limitations these calibration methods impose have been a significant impediment to broader use of nondestructive evaluation methods such as ground-penetrating radar (GPR). In 2006, a new rapid, continuous calibration approach was designed using simulation software to address these measurement limitations during a Federal Highway Administration (FHWA) research and development effort. This continuous calibration method combines a digitally-synthesized step-frequency (SF)-GPR array and a data collection protocol sequence for the common midpoint (CMP) method. Modeling and laboratory test results for various data collection protocols and materials are presented in this paper. The continuous-CMP concept was finally implemented for FHWA in a prototype demonstration system called the Advanced Pavement Evaluation (APE) system in 2009. Data from the continuous-CMP protocol is processed using a semblance/coherency analysis to determine material propagation velocities. Continuously calibrated pavement thicknesses measured with the APE system in 2009 are presented. This method is efficient, accurate, and cost-effective.

  12. Application of dual volume reconstruction technique in embolization of intracranial aneurysms

    Directory of Open Access Journals (Sweden)

    Xiang-hai ZHANG

    2014-03-01

    Full Text Available Objective To explore the value of dual volume reconstruction technique in Guglielmi detachable coil (GDC embolization of intracranial aneurysms. Methods Three-dimensional imaging data of 20 patients received GDC embolization of intracranial aneurysms from Jun. 2012 to Apr. 2013 were analyzed for dual volume reconstruction. The value of application of dual volume reconstruction was evaluated by the detection rate of coils bolus, degree of aneurysm occlusion, the length of aneurysm sac and aneurysm neck before and after embolization, and the characteristics and clinical value of the reconstructed images. Results  A total of 20 coil boluses were detected by dual volume reconstruction images, and the detection rate was 100%. Among all of 20 patients, no visualization of contrast medium in the aneurysm was found in 13 patients, while contrast agent was found in the aneurysm sac in 3 patients and in the aneurysm neck in 4 patients. The length of aneurysm neck and sac was somewhat changed before and after embolization with no statistically significant difference (P>0.05. The dual volume reconstruction could reveal coil bolus, vessels, cranium and fusion images, and the aneurysms could be shown by different imaging modes according to the clinical requirement. Conclusion Dual volume reconstruction technique can display the location of coil bolus, degree of occlusion and aneurysm size, and evaluate the embolization effect by multifarious imaging modes, providing a great deal of information for the evaluation of GDC embolization of intracranial aneurysm. DOI: 10.11855/j.issn.0577-7402.2014.02.13

  13. Joint Data Assimilation and Parameter Calibration in on-line groundwater modelling using Sequential Monte Carlo techniques

    Science.gov (United States)

    Ramgraber, M.; Schirmer, M.

    2017-12-01

    As computational power grows and wireless sensor networks find their way into common practice, it becomes increasingly feasible to pursue on-line numerical groundwater modelling. The reconciliation of model predictions with sensor measurements often necessitates the application of Sequential Monte Carlo (SMC) techniques, most prominently represented by the Ensemble Kalman Filter. In the pursuit of on-line predictions it seems advantageous to transcend the scope of pure data assimilation and incorporate on-line parameter calibration as well. Unfortunately, the interplay between shifting model parameters and transient states is non-trivial. Several recent publications (e.g. Chopin et al., 2013, Kantas et al., 2015) in the field of statistics discuss potential algorithms addressing this issue. However, most of these are computationally intractable for on-line application. In this study, we investigate to what extent compromises between mathematical rigour and computational restrictions can be made within the framework of on-line numerical modelling of groundwater. Preliminary studies are conducted in a synthetic setting, with the goal of transferring the conclusions drawn into application in a real-world setting. To this end, a wireless sensor network has been established in the valley aquifer around Fehraltorf, characterized by a highly dynamic groundwater system and located about 20 km to the East of Zürich, Switzerland. By providing continuous probabilistic estimates of the state and parameter distribution, a steady base for branched-off predictive scenario modelling could be established, providing water authorities with advanced tools for assessing the impact of groundwater management practices. Chopin, N., Jacob, P.E. and Papaspiliopoulos, O. (2013): SMC2: an efficient algorithm for sequential analysis of state space models. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 75 (3), p. 397-426. Kantas, N., Doucet, A., Singh, S

  14. Advanced energy sources and conversion techniques. Proceedings of a seminar. Volume 1. [35 papers

    Energy Technology Data Exchange (ETDEWEB)

    None

    1958-11-01

    The Seminar was organized as a series of tutorial presentations and round table discussions on a technical level to implement the following: (a) to identify and explore present and projected needs for energy sources and conversion techniques for military applications; (b) to exchange information on current and planned efforts in these fields; (c) to examine the effect of anticipated scientific and technological advances on these efforts; and (d) to present suggested programs aimed at satisfying the military needs for energy sources and conversion techniques. Volume I contains all of the unclassified papers presented at the Seminar. (W.D.M.)

  15. A two isocenter IMRT technique with a controlled junction dose for long volume targets

    International Nuclear Information System (INIS)

    Zeng, G G; Heaton, R K; Catton, C N; Chung, P W; O'Sullivan, B; Lau, M; Parent, A; Jaffray, D A

    2007-01-01

    Most IMRT techniques have been designed to treat targets smaller than the field size of conventional linac accelerators. In order to overcome the field size restrictions in applying IMRT, we developed a two isocenter IMRT technique to treat long volume targets. The technique exploits an extended dose gradient throughout a junction region of 4-6 cm to minimize the impact of field match errors on a junction dose and manipulates the inverse planning and IMRT segments to fill in the dose gradient and achieve dose uniformity. Techniques for abutting both conventional fields with IMRT ('Static + IMRT') and IMRT fields ('IMRT + IMRT') using two separate isocenters have been developed. Five long volume sarcoma cases have been planned in Pinnacle (Philips, Madison, USA) using Elekta Synergy and Varian 2100EX linacs; two of the cases were clinically treated with this technique. Advantages were demonstrated with well-controlled junction target uniformity and tolerance to setup uncertainties. The junction target dose heterogeneity was controlled at a level of ±5%; for 3 mm setup errors at the field edges, the junction target dose changed less than 5% and the dose sparing to organs at risk (OARs) was maintained. Film measurements confirmed the treatment planning results

  16. Comparison of Electrostatic Fins with Piezoelectric Impact Hammer Techniques to Extend Impulse Calibration Range of a Torsional Thrust Stand (Preprint)

    Science.gov (United States)

    2011-03-23

    prac- tical max impulse to 1mNs. The newly developed Piezo - electric Impact Hammer (PIH) calibration system over- comes geometric limits of ESC...the fins to behave as part of an LRC circuit which results in voltage oscillations. By adding a resistor in series between the pulse generator and...series resistor as well as the effects of no loading on the pulse generator. III. PIEZOELECTRIC IMPACT HAMMER SYSTEM The second calibration method tested

  17. Development of volume reduction treatment techniques for low level radioactive wastes

    International Nuclear Information System (INIS)

    Nabatame, Yasuzi

    1984-01-01

    The solid wastes packed in drums are preserved in the stores of nuclear establishments in Japan, and the quantity of preservation has already reached about 60 % of the capacity. It has become an important subject to reduce the quantity of generation of radioactive wastes and how to reduce the volume of generated wastes. As the result of the research aiming at the development of the solidified bodies which are excellent in the effect of volume reduction and physical properties, it was confirmed that the plastic solidified bodies using thermosetting resin were superior to conventional cement or asphalt solidification. The plastic solidifying system can treat various radioactive wastes. After radioactive wastes are dried and powdered, they are solidified with plastics, therefore, the effect of volume reduction is excellent. The specific gravity, strength and the resistance to water, fire and radiation were confirmed to be satisfacotory. The plastic solidifying system comprises three subsystems, that is, drying system, powder storing and supplying system and plastic solidifying system. Also the granulation technique after drying and powdering, acid decomposition technique, the microwave melting and solidifying technique for incineration ash, plasma melting process and electrolytic polishing decontamination are described. (Kako, I.)

  18. 'Dip-sticks' calibration handles self-attenuation and coincidence effects in large-volume gamma-ray spectrometry

    CERN Document Server

    Wolterbeek, H T

    2000-01-01

    Routine gamma-spectrometric analyses of samples with low-level activities (e.g. food, water, environmental and industrial samples) are often performed in large samples, placed close to the detector. In these geometries, detection sensitivity is improved but large errors are introduced due to self-attenuation and coincidence summing. Current approaches to these problems comprise computational methods and spiked standard materials. However, the first are often regarded as too complex for practical routine use, the latter never fully match real samples. In the present study, we introduce a dip-sticks calibration as a fast and easy practical solution to this quantification problem in a routine analytical setting. In the proposed set-up, calibrations are performed within the sample itself, thus making it a broadly accessible matching-reference approach, which is principally usable for all sample matrices.

  19. Syringe shape and positioning relative to efficiency volume inside dose calibrators and its role in nuclear medicine quality assurance programs

    International Nuclear Information System (INIS)

    Santos, J.A.M.; Carrasco, M.F.; Lencart, J.; Bastos, A.L.

    2009-01-01

    A careful analysis of geometry and source positioning influence in the activity measurement outcome of a nuclear medicine dose calibrator is presented for 99m Tc. The implementation of a quasi-point source apparent activity curve measurement is proposed for an accurate correction of the activity inside several syringes, and compared with a theoretical geometric efficiency model. Additionally, new geometrical parameters are proposed to test and verify the correct positioning of the syringes as part of acceptance testing and quality control procedures.

  20. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 4: Accurate determination of liquid height in accountancy tanks equipped with dip tubes, slow bubbling rate

    International Nuclear Information System (INIS)

    2008-01-01

    ISO 18213 deals with the acquisition, standardization, analysis, and use of calibration to determine liquid volumes in process tanks for the accountancy of nuclear materials. This part of ISO 18213 is complementary to the other parts, ISO 18213-1 (procedural overview), ISO 18213-2 (data standardization), ISO 18213-3 (statistical methods), ISO 18213-5 (fast bubbling rate) and ISO 18213-6 (in-tank determination of liquid density). The procedure presented herein for determining liquid height from measurements of induced pressure applies specifically when a very slow bubbling rate is employed. A similar procedure that is appropriate for a fast bubbling rate is given in ISO 18213-5. Measurements of the volume and height of liquid in a process accountancy tank are often made in order to estimate or verify the tank's calibration or volume measurement equation. The calibration equation relates the response of the tank's measurement system to some independent measure of tank volume. Beginning with an empty tank, calibration data are typically acquired by introducing a series of carefully measured quantities of some calibration liquid into the tank. The quantity of liquid added, the response of the tank's measurement system, and relevant ambient conditions such as temperature are measured for each incremental addition. Several calibration runs are made to obtain data for estimating or verifying a tank's calibration or measurement equation. A procedural overview of the tank calibration and volume measurement process is given in ISO 18213-1. An algorithm for standardizing tank calibration and volume measurement data to minimize the effects of variability in ambient conditions that prevail during the measurement period is given in ISO 18213-2. The procedure presented in this part of ISO 18213 for determining the height of calibration liquid in the tank from a measurement of the pressure it induces in the tank's measurement system is a vital component of that algorithm. In some

  1. Nuclear fuel technology - Tank calibration and volume determination for nuclear materials accountancy - Part 5: Accurate determination of liquid height in accountancy tanks equipped with dip tubes, fast bubbling rate

    International Nuclear Information System (INIS)

    2008-01-01

    ISO 18213 deals with the acquisition, standardization, analysis, and use of calibration to determine liquid volumes in process tanks for the accountancy of nuclear materials. This part of ISO 18213 is complementary to the other parts, ISO 18213-1 (procedural overview), ISO 18213-2 (data standardization), ISO 18213-3 (statistical methods), ISO 18213-5 (fast bubbling rate) and ISO 18213-6 (in-tank determination of liquid density). The procedure presented herein for determining liquid height from measurements of induced pressure applies specifically when a very slow bubbling rate is employed. A similar procedure that is appropriate for a fast bubbling rate is given in ISO 18213-5. Measurements of the volume and height of liquid in a process accountancy tank are often made in order to estimate or verify the tank's calibration or volume measurement equation. The calibration equation relates the response of the tank's measurement system to some independent measure of tank volume. Beginning with an empty tank, calibration data are typically acquired by introducing a series of carefully measured quantities of some calibration liquid into the tank. The quantity of liquid added, the response of the tank's measurement system, and relevant ambient conditions such as temperature are measured for each incremental addition. Several calibration runs are made to obtain data for estimating or verifying a tank's calibration or measurement equation. A procedural overview of the tank calibration and volume measurement process is given in ISO 18213-1. An algorithm for standardizing tank calibration and volume measurement data to minimize the effects of variability in ambient conditions that prevail during the measurement period is given in ISO 18213-2. The procedure presented in this part of ISO 18213 for determining the height of calibration liquid in the tank from a measurement of the pressure it induces in the tank's measurement system is a vital component of that algorithm. In some

  2. Tracer techniques for urine volume determination and urine collection and sampling back-up system

    Science.gov (United States)

    Ramirez, R. V.

    1971-01-01

    The feasibility, functionality, and overall accuracy of the use of lithium were investigated as a chemical tracer in urine for providing a means of indirect determination of total urine volume by the atomic absorption spectrophotometry method. Experiments were conducted to investigate the parameters of instrumentation, tracer concentration, mixing times, and methods for incorporating the tracer material in the urine collection bag, and to refine and optimize the urine tracer technique to comply with the Skylab scheme and operational parameters of + or - 2% of volume error and + or - 1% accuracy of amount of tracer added to each container. In addition, a back-up method for urine collection and sampling system was developed and evaluated. This back-up method incorporates the tracer technique for volume determination in event of failure of the primary urine collection and preservation system. One chemical preservative was selected and evaluated as a contingency chemical preservative for the storage of urine in event of failure of the urine cooling system.

  3. PETPVC: a toolbox for performing partial volume correction techniques in positron emission tomography

    Science.gov (United States)

    Thomas, Benjamin A.; Cuplov, Vesna; Bousse, Alexandre; Mendes, Adriana; Thielemans, Kris; Hutton, Brian F.; Erlandsson, Kjell

    2016-11-01

    Positron emission tomography (PET) images are degraded by a phenomenon known as the partial volume effect (PVE). Approaches have been developed to reduce PVEs, typically through the utilisation of structural information provided by other imaging modalities such as MRI or CT. These methods, known as partial volume correction (PVC) techniques, reduce PVEs by compensating for the effects of the scanner resolution, thereby improving the quantitative accuracy. The PETPVC toolbox described in this paper comprises a suite of methods, both classic and more recent approaches, for the purposes of applying PVC to PET data. Eight core PVC techniques are available. These core methods can be combined to create a total of 22 different PVC techniques. Simulated brain PET data are used to demonstrate the utility of toolbox in idealised conditions, the effects of applying PVC with mismatched point-spread function (PSF) estimates and the potential of novel hybrid PVC methods to improve the quantification of lesions. All anatomy-based PVC techniques achieve complete recovery of the PET signal in cortical grey matter (GM) when performed in idealised conditions. Applying deconvolution-based approaches results in incomplete recovery due to premature termination of the iterative process. PVC techniques are sensitive to PSF mismatch, causing a bias of up to 16.7% in GM recovery when over-estimating the PSF by 3 mm. The recovery of both GM and a simulated lesion was improved by combining two PVC techniques together. The PETPVC toolbox has been written in C++, supports Windows, Mac and Linux operating systems, is open-source and publicly available.

  4. Syringe shape and positioning relative to efficiency volume inside dose calibrators and its role in nuclear medicine quality assurance programs

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.A.M. [Servico de Fisica Medica, Instituto Portugues de Oncologia do Porto Francisco Gentil, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200072 Porto (Portugal); Centro de Investigacao, Instituto Portugues de Oncologia do Porto Francisco Gentil, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200072 Porto (Portugal)], E-mail: a.miranda@portugalmail.pt; Carrasco, M.F. [Servico de Fisica Medica, Instituto Portugues de Oncologia do Porto Francisco Gentil, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200072 Porto (Portugal); Centro de Investigacao, Instituto Portugues de Oncologia do Porto Francisco Gentil, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200072 Porto (Portugal); Lencart, J. [Servico de Fisica Medica, Instituto Portugues de Oncologia do Porto Francisco Gentil, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200072 Porto (Portugal); Bastos, A.L. [Servico de Medicina Nuclear, Instituto Portugues de Oncologia do Porto Francisco Gentil, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200072 Porto (Portugal)

    2009-06-15

    A careful analysis of geometry and source positioning influence in the activity measurement outcome of a nuclear medicine dose calibrator is presented for {sup 99m}Tc. The implementation of a quasi-point source apparent activity curve measurement is proposed for an accurate correction of the activity inside several syringes, and compared with a theoretical geometric efficiency model. Additionally, new geometrical parameters are proposed to test and verify the correct positioning of the syringes as part of acceptance testing and quality control procedures.

  5. Standardization of pulmonary ventilation technique using volume-controlled ventilators in rats with congenital diaphragmatic hernia

    Directory of Open Access Journals (Sweden)

    Rodrigo Melo Gallindo

    Full Text Available OBJECTIVE: To standardize a technique for ventilating rat fetuses with Congenital Diaphragmatic Hernia (CDH using a volume-controlled ventilator. METHODS: Pregnant rats were divided into the following groups: a control (C; b exposed to nitrofen with CDH (CDH; and c exposed to nitrofen without CDH (N-. Fetuses of the three groups were randomly divided into the subgroups ventilated (V and non-ventilated (N-V. Fetuses were collected on day 21.5 of gestation, weighed and ventilated for 30 minutes using a volume-controlled ventilator. Then the lungs were collected for histological study. We evaluated: body weight (BW, total lung weight (TLW, left lung weight (LLW, ratios TLW / BW and LLW / BW, morphological histology of the airways and causes of failures of ventilation. RESULTS: BW, TLW, LLW, TLW / BW and LLW / BW were higher in C compared with N- (p 0.05. The morphology of the pulmonary airways showed hypoplasia in groups N- and CDH, with no difference between V and N-V (p <0.05. The C and N- groups could be successfully ventilated using a tidal volume of 75 ìl, but the failure of ventilation in the CDH group decreased only when ventilated with 50 ìl. CONCLUSION: Volume ventilation is possible in rats with CDH for a short period and does not alter fetal or lung morphology.

  6. Absolute dose calibration of an X-ray system and dead time investigations of photon-counting techniques

    CERN Document Server

    Carpentieri, C; Ludwig, J; Ashfaq, A; Fiederle, M

    2002-01-01

    High precision concerning the dose calibration of X-ray sources is required when counting and integrating methods are compared. The dose calibration for a dental X-ray tube was executed with special dose calibration equipment (dosimeter) as function of exposure time and rate. Results were compared with a benchmark spectrum and agree within +-1.5%. Dead time investigations with the Medipix1 photon-counting chip (PCC) have been performed by rate variations. Two different types of dead time, paralysable and non-paralysable will be discussed. The dead time depends on settings of the front-end electronics and is a function of signal height, which might lead to systematic defects of systems. Dead time losses in excess of 30% have been found for the PCC at 200 kHz absorbed photons per pixel.

  7. RF impedance measurement calibration

    International Nuclear Information System (INIS)

    Matthews, P.J.; Song, J.J.

    1993-01-01

    The intent of this note is not to explain all of the available calibration methods in detail. Instead, we will focus on the calibration methods of interest for RF impedance coupling measurements and attempt to explain: (1). The standards and measurements necessary for the various calibration techniques. (2). The advantages and disadvantages of each technique. (3). The mathematical manipulations that need to be applied to the measured standards and devices. (4). An outline of the steps needed for writing a calibration routine that operated from a remote computer. For further details of the various techniques presented in this note, the reader should consult the references

  8. BES online calibration system

    International Nuclear Information System (INIS)

    Zhang Bingyun; Li Xiaonan; Zhu Kejun; Zhang Jiawen; Gong Mingyu

    2003-01-01

    We constructed BES (Beijing Spectrometer) online calibration system to ensure the coherence of readout electronic channels due to huge data volume in high energy physics experiment. This paper describes the structure of hardware and software, and its characteristic and function

  9. Visualization of normal and abnormal inner ear with volume rendering technique using multislice spiral CT

    International Nuclear Information System (INIS)

    Ma Hui; Han Ping; Liang Bo; Lei Ziqiao; Liu Fang; Tian Zhiliang

    2006-01-01

    Objective: To evaluate the ability of the volume rendering technique to display the normal and abnormal inner ear structures. Methods: Forty normal earand 61 abnormal inner ears (40 congenital inner ear malformations, 7 labyrinthitis ossificans, and 14 inner ear erosion caused by cholesteatomas) were examined with a MSCT scanner. Axial imaging were performed using the following parameters: 120 kV, 100 mAs, 0.75 mm slice thickness, a pitch factor of 1. The axial images of interested ears were reconstructed with 0.1 mm reconstruction increment and a FOV of 50 mm. The 3D reconstructions were done with volume rendering technique on the workstation. Results: In the subjects without ear disorders a high quality 3D visualization of the inner ear could be achieved. In the patients with inner ear' disorders all inner ear malformations could be clearly displayed on 3D images as follows: (1) Michel deformity (one ear): There was complete absence of all cochlear and vestibular structures. (2) common cavity deformity (3 ears): The cochlea and vestibule were represented by a cystic cavity and couldn't be differentiated from each other. (3)incomplete partition type I (3 ears): The cochlea lacked the entire modiolus and cribriform area, resulting in a cystic appearance. (4) incomplete partition type II (Mondini deformity) (5 ears): The cochlea consisted of 1.5 turns, in which the middle and apical turns coalesced to form a cystic apex. (5) vestibular and semicircular canal malformations (14 ears): Cochlea was normal, vestibule dilated, semicircular canals were absent, hypoplastic or enlarged. (6) dilated vestibular aqueduct (14 ears): The vestibular aqueduct was bell-mouthed. In 7 patients with labyrinthifis ossificans, 3D images failed to clearly show the completeinner ears in 4 ears because of too high ossifications in the membranous labyrinth. In the other 3 ears volume rendering could display the thin cochlea basal turn and the intermittent semicircular canals. In the patients

  10. Calibration of a micromachined particle velocity microphone in a standing wave tube using a LDA photon-correlation technique

    NARCIS (Netherlands)

    Raangs, R.; Schlicke, Ted; Barham, Richard

    2005-01-01

    In this paper, a new method of calibrating an acoustic particle velocity sensor using laser Doppler anemometry (LDA) is discussed. The results were compared and were in good agreement with the results obtained by conventional methods, where the sensitivity of the microflown is obtained with the use

  11. MUSIC. a fast T2* - sensitive MRI technique with enhanced volume coverage

    International Nuclear Information System (INIS)

    Loenneker, Thomas; Hennig, Juergen

    1994-01-01

    A fast imaging method based on gradient-recalled echoes and echo time inter-leaved multi-slice excitation is presented. This method maintains the sensitivity of T 2 * by using a long echo time of at least 35 milliseconds. Bipolar gradients are used to shift the gradient echoes in order to ensure constant TE for each slab and prevent ghost-artefacts within the images caused by spin- or stimulated echoes. This method enhances the total imaging time of a conventional multi-slice gradient echo technique, while maintaining the high volume coverage. Thus, stimulated human cortical activation maps can be detected on standard clinical MR instruments at several planes within measuring times of a few seconds. The efficiency of the technique is demonstrated in the detection of temporary changes in T 2 * in functional MRI experiments of the human visual cortex at a magnetic field strength of 2 tesla. (author). 18 refs., 6 figs

  12. Development of a high-order finite volume method with multiblock partition techniques

    Directory of Open Access Journals (Sweden)

    E. M. Lemos

    2012-03-01

    Full Text Available This work deals with a new numerical methodology to solve the Navier-Stokes equations based on a finite volume method applied to structured meshes with co-located grids. High-order schemes used to approximate advective, diffusive and non-linear terms, connected with multiblock partition techniques, are the main contributions of this paper. Combination of these two techniques resulted in a computer code that involves high accuracy due the high-order schemes and great flexibility to generate locally refined meshes based on the multiblock approach. This computer code has been able to obtain results with higher or equal accuracy in comparison with results obtained using classical procedures, with considerably less computational effort.

  13. Volume Recovery of Polymeric Glasses: Application of a Capacitance-based Measurement Technique

    Science.gov (United States)

    Sakib, Nazam; Simon, Sindee

    Glasses, including polymeric glasses, are inherently non-equilibrium materials. As a consequence, the volume and enthalpy of a glass evolve towards equilibrium in a process termed structural recovery. Several open questions and new controversies remain unanswered in the field. Specifically, the presence of intermediate plateaus during isothermal structural recovery has been reported in recent enthalpy work. In addition, the dependence of the relaxation time on state variables and thermal history is unclear. Dilatometry is particularly useful for structural recovery studies because volume is an absolute quantity and volumetric measurements can be done in-situ. A capillary dilatometer, fitted with a linear variable differential transducer, was used previously to measure volume recovery of polymeric glass formers in our laboratory. To improve on the limitations associated with that methodology, including competition between the range of measurements versus the sensitivity, a capacitance-based technique has been developed following the work of Richert, 2010. The modification is performed by converting the glass capillary dilatometer into a cylindrical capacitor. For precision in capacitance data acquisition, an Andeen-Hagerling ultra-precision capacitance bridge (2550A, 1 kHz) is used. The setup will be tested by performing the signatures of structural recovery as described by Kovacs, 1963. Experiments are also planned to address the open questions in the field.

  14. Optimization of quantitative waste volume determination technique for hanford waste tank closure

    International Nuclear Information System (INIS)

    Monts, David L.; Jang, Ping-Rey; Long, Zhiling; Okhuysen, Walter P.; Norton, Olin P.; Gresham, Lawrence L.; Su, Yi; Lindner, Jeffrey S.

    2011-01-01

    The Hanford Site is currently in the process of an extensive effort to empty and close its radioactive single-shell and double-shell waste storage tanks. Before this can be accomplished, it is necessary to know how much residual material is left in a given waste tank and the uncertainty with which that volume is known. The Institute for Clean Energy Technology (ICET) at Mississippi State University is currently developing a quantitative in-tank imaging system based on Fourier Transform Profilometry, FTP. FTP is a non-contact, 3-D shape measurement technique. By projecting a fringe pattern onto a target surface and observing its deformation due to surface irregularities from a different view angle, FTP is capable of determining the height (depth) distribution (and hence volume distribution) of the target surface, thus reproducing the profile of the target accurately under a wide variety of conditions. Hence FTP has the potential to be utilized for quantitative determination of residual wastes within Hanford waste tanks. In this paper, efforts to characterize the accuracy and precision of quantitative volume determination using FTP and the use of these results to optimize the FTP system for deployment within Hanford waste tanks are described. (author)

  15. Comparison of rectal volume definition techniques and their influence on rectal toxicity in patients with prostate cancer treated with 3D conformal radiotherapy: a dose-volume analysis

    International Nuclear Information System (INIS)

    Onal, Cem; Topkan, Erkan; Efe, Esma; Yavuz, Melek; Sonmez, Serhat; Yavuz, Aydin

    2009-01-01

    To evaluate the impact of four different rectum contouring techniques and rectal toxicities in patients with treated with 3D conformal radiotherapy (3DCRT). Clinical and dosimetric data were evaluated for 94 patients who received a total dose 3DCRT of 70 Gy, and rectal doses were compared in four different rectal contouring techniques: the prostate-containing CT sections (method 1); 1 cm above and below the planning target volume (PTV) (method 2); 110 mm starting from the anal verge (method 3); and from the anal verge to the sigmoid flexure (method 4). The percentage of rectal volume receiving RT doses (30–70 Gy) and minimum, mean rectal doses were assessed. Median age was 69 years. Percentage of rectal volume receiving high doses (≥ 70 Gy) were higher with the techniques that contoured smaller rectal volumes. In methods 2 and 3, the percentage of rectal volume receiving ≥ 70 Gy was significantly higher in patients with than without rectal bleeding (method 2: 30.8% vs. 22.5%, respectively (p = 0.03); method 3: 26.9% vs. 18.1%, respectively (p = 0.006)). Mean rectal dose was significant predictor of rectal bleeding only in method 3 (48.8 Gy in patients with bleeding vs. 44.4 Gy in patients without bleeding; p = 0.02). Different techniques of rectal contouring significantly influence the calculation of radiation doses to the rectum and the prediction of rectal toxicity. Rectal volume receiving higher doses (≥ 70 Gy) and mean rectal doses may significantly predict rectal bleeding for techniques contouring larger rectal volumes, as was in method 3

  16. Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Cesar M.; Brandao, Luis E.B., E-mail: otero@ien.gov.br, E-mail: brandao@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase's densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a ({sup 137}Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose. (author)

  17. Volume fraction prediction in biphasic flow using nuclear technique and artificial neural network

    International Nuclear Information System (INIS)

    Salgado, Cesar M.; Brandao, Luis E.B.

    2015-01-01

    The volume fraction is one of the most important parameters used to characterize air-liquid two-phase flows. It is a physical value to determine other parameters, such as the phase's densities and to determine the flow rate of each phase. These parameters are important to predict the flow pattern and to determine a mathematical model for the system. To study, for example, heat transfer and pressure drop. This work presents a methodology for volume fractions prediction in water-gas stratified flow regime using the nuclear technique and artificial intelligence. The volume fractions calculate in biphasic flow systems is complex and the analysis by means of analytical equations becomes very difficult. The approach is based on gamma-ray pulse height distributions pattern recognition by means of the artificial neural network. The detection system uses appropriate broad beam geometry, comprised of a ( 137 Cs) energy gamma-ray source and a NaI(Tl) scintillation detector in order measure transmitted beam whose the counts rates are influenced by the phases composition. These distributions are directly used by the network without any parameterization of the measured signal. The ideal and static theoretical models for stratified regime have been developed using MCNP-X code, which was used to provide training, test and validation data for the network. The detector also was modeled with this code and the results were compared to experimental photopeak efficiency measurements of radiation sources. The proposed network could obtain with satisfactory prediction of the volume fraction in water-gas system, demonstrating to be a promising approach for this purpose. (author)

  18. Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Vanessa Lessa; Souza-Gabriel, Aline Evangelista; Cruz Filho, Antonio Miranda da; Pecora, Jesus Djalma; Silva, Ricardo Gariba, E-mail: vanessalessa@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Escola de Odontologia. Departamento de Odontologia Restauradora

    2016-05-01

    The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT). Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26) and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each). Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm{sup 3}) in the apical region was analyzed using the two-way ANOVA and post-hoc Student-Newman-Keuls test (α = 0.05). The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009) and Endofill (0.103 ± 0.010). The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008) and Sealer 26 (0.109 ± 0.018) (p > 0.05). Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012) (p < 0.05). Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique. (author)

  19. Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis

    International Nuclear Information System (INIS)

    Araujo, Vanessa Lessa; Souza-Gabriel, Aline Evangelista; Cruz Filho, Antonio Miranda da; Pecora, Jesus Djalma; Silva, Ricardo Gariba

    2016-01-01

    The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT). Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26) and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each). Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm 3 ) in the apical region was analyzed using the two-way ANOVA and post-hoc Student-Newman-Keuls test (α = 0.05). The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009) and Endofill (0.103 ± 0.010). The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008) and Sealer 26 (0.109 ± 0.018) (p > 0.05). Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012) (p < 0.05). Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique. (author)

  20. Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

    International Nuclear Information System (INIS)

    Didier, Ryne A.; Vajtai, Petra L.; Hopkins, Katharine L.

    2015-01-01

    Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI vol ). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI vol . Reduced CTDI vol was achieved primarily by reductions in effective tube current-time product (mAs eff ) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI vol , size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI vol was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI vol and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

  1. Iterative reconstruction technique with reduced volume CT dose index: diagnostic accuracy in pediatric acute appendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Didier, Ryne A. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Vajtai, Petra L. [Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States); Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Hopkins, Katharine L. [Oregon Health and Science University, Department of Diagnostic Radiology, DC7R, Portland, OR (United States); Oregon Health and Science University, Department of Pediatrics, Portland, OR (United States)

    2014-07-05

    Iterative reconstruction technique has been proposed as a means of reducing patient radiation dose in pediatric CT. Yet, the effect of such reductions on diagnostic accuracy has not been thoroughly evaluated. This study compares accuracy of diagnosing pediatric acute appendicitis using contrast-enhanced abdominopelvic CT scans performed with traditional pediatric weight-based protocols and filtered back projection reconstruction vs. a filtered back projection/iterative reconstruction technique blend with reduced volume CT dose index (CTDI{sub vol}). Results of pediatric contrast-enhanced abdominopelvic CT scans done for pain and/or suspected appendicitis were reviewed in two groups: A, 192 scans performed with the hospital's established weight-based CT protocols and filtered back projection reconstruction; B, 194 scans performed with iterative reconstruction technique and reduced CTDI{sub vol}. Reduced CTDI{sub vol} was achieved primarily by reductions in effective tube current-time product (mAs{sub eff}) and tube peak kilovoltage (kVp). CT interpretation was correlated with clinical follow-up and/or surgical pathology. CTDI{sub vol}, size-specific dose estimates (SSDE) and performance characteristics of the two CT techniques were then compared. Between groups A and B, mean CTDI{sub vol} was reduced by 45%, and mean SSDE was reduced by 46%. Sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group A vs. 100%, 99% and 99% in group B. Accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic CT scans that incorporated iterative reconstruction technique, despite reductions in mean CTDI{sub vol} and SSDE by nearly half as compared to the hospital's traditional weight-based protocols. (orig.)

  2. Energy calibration of a 5. 5 MV Van de Graaff accelerator using a time-of-flight technique

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E.; Feregrino, M.; Zavala, E.P.; Pineda, J.C.; Jimenez, R.; Jaidar, A. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica (Mexico))

    1990-02-01

    Energy calibration of the analysing magnet for the University of Mexico 5.5 MV Van de Graaff accelerator has been carried out using a time-of-flight method. The pulsed and bunched beam produced by the accelerator was used to deduce the energy E of the beam particles from the transit time between a coaxial pickup and a charged particle detector separated by 1.5 m. The measured FWHM energy resolution of this system was about 20 keV. (orig.).

  3. Energy calibration of a 5.5 MV Van de Graaff accelerator using a time-of-flight technique

    Science.gov (United States)

    Andrade, E.; Feregrino, M.; Zavala, E. P.; Pineda, J. C.; Jiménez, R.; Jaidar, A.

    1990-02-01

    Energy calibration of the analysing magnet for the University of México 5.5 MV Van de Graaff accelerator has been carried out using a time-of-flight method. The pulsed and bunched beam produced by the accelerator was used to deduce the energy E of the beam particles from the transit time between a coaxial pickup and a charged particle detector separated by 1.5 m. The measured FWHM energy resolution of this system was about 20 keV.

  4. Usefulness of Oncoplastic Volume Replacement Techniques after Breast Conserving Surgery in Small to Moderate-sized Breasts

    Directory of Open Access Journals (Sweden)

    Jung Dug Yang

    2012-09-01

    Full Text Available BackgroundIn Korean women, many of whom have small to moderate-sized breasts, it is difficult to cover a partial breast defect using oncoplastic volume displacement techniques after removal of an adequate volume of tissue during oncologic surgery. In such cases, oncoplastic volume replacement techniques are more useful.MethodsFrom January 2007 to December 2011, 104 women underwent a total of 107 breast-conserving surgeries with various kinds of oncoplastic volume replacement techniques. We used latissimus dorsi (LD myocutaneous flap for cases in which the resection mass was greater than 150 g. In case with a resection mass less than 150 g, we used regional flaps such as a lateral thoracodorsal flap, a thoracoepigastric flap, or perforator flaps such as an intercostal artery perforator (ICAP flap or a thoracodorsal artery perforator (TDAP flap.ResultsThe mean age was 46.1 years, and the average follow-up interval was 10.3 months. The patients underwent oncoplastic volume replacement techniques with a lateral thoracodorsal flap (n=9, thoracoepigastric flap (n=7, ICAP flap (n=25, TDAP flap (n=12, and LD flap (n=54. There was one case of congestion in an LD flap, and two cases of fat necrosis in an ICAP flap. Most of the patients were satisfied with the cosmetic results.ConclusionsOncoplastic volume replacement techniques can be reliable and useful for the correction of breast deformity after breast-conserving surgery, especially in patients with small to moderate-sized breasts.

  5. Whole-brain perfusion CT using a toggling table technique to predict final infarct volume in acute ischemic stroke.

    Science.gov (United States)

    Schrader, I; Wilk, D; Jansen, O; Riedel, C

    2013-09-01

    To evaluate how accurately final infarct volume in acute ischemic stroke can be predicted with perfusion CT (PCT) using a 64-MDCT unit and the toggling table technique. Retrospective analysis of 89 patients with acute ischemic stroke who underwent CCT, CT angiography (CTA) and PCT using the "toggling table" technique within the first three hours after symptom onset. In patients with successful thrombolytic therapy (n = 48) and in those without effective thrombolytic therapy (n = 41), the infarct volume and the volume of the penumbra on PCT were compared to the infarct size on follow-up images (CT or MRI) performed within 8 days. The feasibility of complete infarct volume prediction by 8 cm cranio-caudal coverage was evaluated. The correlation between the volume of hypoperfusion on PCT defined by cerebral blood volume reduction and final infarct volume was strongest in patients with successful thrombolytic therapy with underestimation of the definite infarct volume by 8.5 ml on average. The CBV map had the greatest prognostic value. In patients without successful thrombolytic therapy, the final infarct volume was overestimated by 12.1 ml compared to the MTT map on PCT. All infarcts were detected completely. There were no false-positive or false-negative results. Using PCT and the "toggling table" technique in acute stroke patients is helpful for the rapid and accurate quantification of the minimal final infarct and is therefore a prognostic parameter which has to be evaluated in further studies to assess its impact on therapeutic decision. ▶ Using PCT and the “toggling table technique” allows accurate quantification of the infarct core and penumbra. ▶ It is possible to record dynamic perfusion parameters quickly and easily of almost the entire supratentorial brain volume on a 64-slice MDCT unit. ▶ The technique allows identification of those patients who could profit from thrombolytic therapy outside the established time intervals. © Georg Thieme Verlag

  6. A Software Module for High-Accuracy Calibration of Rings and Cylinders on CMM using Multi-Orientation Techniques (Multi-Step and Reversal methods)

    DEFF Research Database (Denmark)

    Tosello, Guido; De Chiffre, Leonardo

    . The Centre for Geometrical Metrology (CGM) at the Technical University of Denmark takes care of free form measurements, in collaboration with DIMEG, University of Padova, Italy. The present report describes a software module, ROUNDCAL, to be used for high-accuracy calibration of rings and cylinders....... The purpose of the software is to calculate the form error and the least square circle of rings and cylinders by mean of average of pontwise measuring results becoming from so-called multi-orientation techniques (both reversal and multi-step methods) in order to eliminate systematic errors of CMM ....

  7. Homogenization via formal multiscale asymptotics and volume averaging: How do the two techniques compare?

    KAUST Repository

    Davit, Yohan

    2013-12-01

    A wide variety of techniques have been developed to homogenize transport equations in multiscale and multiphase systems. This has yielded a rich and diverse field, but has also resulted in the emergence of isolated scientific communities and disconnected bodies of literature. Here, our goal is to bridge the gap between formal multiscale asymptotics and the volume averaging theory. We illustrate the methodologies via a simple example application describing a parabolic transport problem and, in so doing, compare their respective advantages/disadvantages from a practical point of view. This paper is also intended as a pedagogical guide and may be viewed as a tutorial for graduate students as we provide historical context, detail subtle points with great care, and reference many fundamental works. © 2013 Elsevier Ltd.

  8. Modelling of Evaporator in Waste Heat Recovery System using Finite Volume Method and Fuzzy Technique

    Directory of Open Access Journals (Sweden)

    Jahedul Islam Chowdhury

    2015-12-01

    Full Text Available The evaporator is an important component in the Organic Rankine Cycle (ORC-based Waste Heat Recovery (WHR system since the effective heat transfer of this device reflects on the efficiency of the system. When the WHR system operates under supercritical conditions, the heat transfer mechanism in the evaporator is unpredictable due to the change of thermo-physical properties of the fluid with temperature. Although the conventional finite volume model can successfully capture those changes in the evaporator of the WHR process, the computation time for this method is high. To reduce the computation time, this paper develops a new fuzzy based evaporator model and compares its performance with the finite volume method. The results show that the fuzzy technique can be applied to predict the output of the supercritical evaporator in the waste heat recovery system and can significantly reduce the required computation time. The proposed model, therefore, has the potential to be used in real time control applications.

  9. A Safe, Self-Calibrating, Wireless System for Measuring Volume of Any Fuel at Non-Horizontal Orientation

    Science.gov (United States)

    Woodward, Stanley E.; Taylor, Bryant D.

    2010-01-01

    A system for wirelessly measuring the volume of fluid in tanks at non-horizontal orientation is predicated upon two technologies developed at Langley Research Center. The first is a magnetic field response recorder that powers and interrogates magnetic field response sensors [ Magnetic Field Response Measurement Acquisition System, (LAR-16908), NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 28]. Magnetic field response sensors are a class of sensors that are powered via oscillating magnetic fields and when electrically active respond with their own magnetic fields whose attributes are dependent upon the magnitude of the physical quantity being measured. The response recorder facilitates the use of the second technology, which is a magnetic field response fluid-level sensor ["Wireless Fluid- Level Sensors for Harsh Environments," (LAR-17155), NASA Tech Briefs, Vol. 33, No. 4 (April 2009), page 30]. The method for powering and interrogating the sensors allows them to be completely encased in materials (Fig. 1) that are chemically resilient to the fluid being measured, thereby facilitating measurement of substances (e.g., acids, petroleum, cryogenic, caustic, and the like) that would normally destroy electronic circuitry. When the sensors are encapsulated, no fluid (or fluid vapor) is exposed to any electrical component of the measurement system. There is no direct electrical line from the vehicle or plant power into a fuel container. The means of interrogating and powering the sensors can be completely physically and electrically isolated from the fuel and vapors by placing the sensor on the other side of an electrically non-conductive bulkhead (Fig. 2). These features prevent the interrogation system and its electrical components from becoming an ignition source.

  10. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques

    Directory of Open Access Journals (Sweden)

    O. Schmid

    2006-01-01

    Full Text Available Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP, have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ Aethalometer became commercially available, which covers the visible (VIS to near-infrared (NIR spectral range (λ=450–950 nm, and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999. On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering, which is significantly larger than the factors previously reported (~2 for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external as a likely cause. For

  11. Measurement of liver and spleen volume by computed tomography using point counting technique in chronic liver disease

    International Nuclear Information System (INIS)

    Sato, Hiroyuki

    1983-01-01

    Liver and spleen volume were measured by computed tomography (CT) using point counting technique. This method is very simple and applicable to any kind of CT scanner. The volumes of the livers and spleens estimated by this method correlated with the weights of the corresponding organs measured on autopsy or surgical operation, indication the accuracy and usefulness of this method. Hepatic and splenic volumes were estimated by this method in 48 patients with chronic liver disease and 13 subjects with non-hepatobiliary discase. The mean hepatic volume in non-alcoholic liver cirrhosis but not in alcoholic cirrhosis was significantly smaller than those in non-hepatobiliary disease and other chronic liver diseases. Alcoholic cirrhosis showed significantly larger liver volume than non-alcoholic cirrhosis. In alcoholic fibrosis, the mean hepatic volume was significantly larger than non-hepatobiliary disease. The mean splenic volumes both in alcoholic and non-alcoholic cirrhosis were significantly larger than in other disease. A significantly positive correlation between hepatic and splenic volumes was found in alcoholic cirrhosis but not in non-alcoholic cirrhosis. These results indicate that estimation of hepatic and splenic volumes by this method is useful for the analysis of the pathophysiology of chronic liver disease. (author)

  12. Measurement of β/Λ ratio and calibration of IPEN-MB-01 power reactor using the noise technique

    International Nuclear Information System (INIS)

    Martins, F.R.; Moreira, J.M.L.

    1989-01-01

    The ratio β/Λ and power level for the IPEN-MB-01 critical facility are obtained experimentally through the noise analysis technique. This techniques is based on the determination of the auto and cross-power spectral density of two ionization chambers. The power measurement results obtained for channels 5 and 6 are shown in Table 2. For an effective neutron fraction of 0.00788 a prompt mean generation time of 65 microseconds was obtained. (author) [pt

  13. Dosimetric Comparison of Split Field and Fixed Jaw Techniques for Large IMRT Target Volumes in the Head and Neck

    International Nuclear Information System (INIS)

    Srivastava, Shiv P.; Das, Indra J.; Kumar, Arvind; Johnstone, Peter A.S.

    2011-01-01

    Some treatment planning systems (TPSs), when used for large-field (>14 cm) intensity-modulated radiation therapy (IMRT), create split fields that produce excessive multiple-leaf collimator segments, match-line dose inhomogeneity, and higher treatment times than nonsplit fields. A new method using a fixed-jaw technique (FJT) forces the jaw to stay at a fixed position during optimization and is proposed to reduce problems associated with split fields. Dosimetric comparisons between split-field technique (SFT) and FJT used for IMRT treatment is presented. Five patients with head and neck malignancies and regional target volumes were studied and compared with both techniques. Treatment planning was performed on an Eclipse TPS using beam data generated for Varian 2100C linear accelerator. A standard beam arrangement consisting of nine coplanar fields, equally spaced, was used in both techniques. Institutional dose-volume constraints used in head and neck cancer were kept the same for both techniques. The dosimetric coverage for the target volumes between SFT and FJT for head and neck IMRT plan is identical within ±1% up to 90% dose. Similarly, the organs at risk (OARs) have dose-volume coverage nearly identical for all patients. When the total monitor unit (MU) and segments were analyzed, SFT produces statistically significant higher segments (17.3 ± 6.3%) and higher MU (13.7 ± 4.4%) than the FJT. There is no match line in FJT and hence dose uniformity in the target volume is superior to the SFT. Dosimetrically, SFT and FJT are similar for dose-volume coverage; however, the FJT method provides better logistics, lower MU, shorter treatment time, and better dose uniformity. The number of segments and MU also has been correlated with the whole body radiation dose with long-term complications. Thus, FJT should be the preferred option over SFT for large target volumes.

  14. Volume changes at macro- and nano-scale in epoxy resins studied by PALS and PVT experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Somoza, A. [IFIMAT-UNCentro, Pinto 399, B7000GHG Tandil (Argentina) and CICPBA, Pinto 399, B7000GHG Tandil (Argentina)]. E-mail: asomoza@exa.unicen.edu.ar; Salgueiro, W. [IFIMAT-UNCentro, Pinto 399, B7000GHG Tandil (Argentina); Goyanes, S. [LPMPyMC, Depto. de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Ramos, J. [Materials and Technology Group, Departamento de Ingenieria Quimica y M. Ambiente, Escuela University Politecnica, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pz. Europa 1, 20018 Donostia/San Sebastian (Spain); Mondragon, I. [Materials and Technology Group, Departamento de Ingenieria Quimica y M. Ambiente, Escuela University Politecnica, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pz. Europa 1, 20018 Donostia/San Sebastian (Spain)

    2007-02-15

    A systematic study on changes in the volumes at macro- and nano-scale in epoxy systems cured with selected aminic hardeners at different pre-cure temperatures is presented. Free- and macroscopic specific-volumes were measured by PALS and pressure-volume-temperature techniques, respectively. An analysis of the relation existing between macro- and nano-scales of the thermosetting networks developed by the different chemical structures is shown. The result obtained indicates that the structure of the hardeners governs the packing of the molecular chains of the epoxy network.

  15. Volume of sealer in the apical region of teeth filled by different techniques: a micro-CT analysis

    Directory of Open Access Journals (Sweden)

    Vanessa Lessa ARAÚJO

    2016-01-01

    Full Text Available Abstract The volume of sealer in the apical 1 mm of teeth filled using different techniques was evaluated by micro-commuted tomography (micro-CT. Sixty-four maxillary central incisors were prepared using NiTi rotary instruments. Teeth were randomly distributed into four groups according to root canal sealers (AH Plus, Endofill, Sealapex, and Sealer 26 and subdivided into two subgroups according to the filling techniques (active and passive lateral condensation; n = 8 each. Subsequently, teeth were examined using the 1174 SkyScan micro-CT device. Images were reconstructed using the NRecon software, and the sealer volume (mm3 in the apical region was analyzed using the two-way ANOVA and post-hoc Student–Newman–Keuls test (α = ٠.٠٥. The lowest volume of sealer was observed in teeth filled with Sealapex (0.100 ± 0.009 and Endofill (0.103 ± 0.010. The highest volume was observed in teeth filled with AH Plus (0.112 ± 0.008 and Sealer 26 (0.109 ± 0.018 (p > 0.05. Regarding the filling technique, a lower sealer volume was observed using the active lateral condensation technique compared with that using the passive lateral condensation technique (0.100 ± 0.010 vs. 0.111 ± 0.012 (p < 0.05. Therefore, the lowest volume of sealer was observed in teeth filled with Sealapex and Endofill using the active lateral condensation technique.

  16. Dual-energy digital mammography: Calibration and inverse-mapping techniques to estimate calcification thickness and glandular-tissue ratio

    International Nuclear Information System (INIS)

    Kappadath, S. Cheenu; Shaw, Chris C.

    2003-01-01

    Breast cancer may manifest as microcalcifications in x-ray mammography. Small microcalcifications, essential to the early detection of breast cancer, are often obscured by overlapping tissue structures. Dual-energy imaging, where separate low- and high-energy images are acquired and synthesized to cancel the tissue structures, may improve the ability to detect and visualize microcalcifications. Transmission measurements at two different kVp values were made on breast-tissue-equivalent materials under narrow-beam geometry using an indirect flat-panel mammographic imager. The imaging scenario consisted of variable aluminum thickness (to simulate calcifications) and variable glandular ratio (defined as the ratio of the glandular-tissue thickness to the total tissue thickness) for a fixed total tissue thickness--the clinical situation of microcalcification imaging with varying tissue composition under breast compression. The coefficients of the inverse-mapping functions used to determine material composition from dual-energy measurements were calculated by a least-squares analysis. The linear function poorly modeled both the aluminum thickness and the glandular ratio. The inverse-mapping functions were found to vary as analytic functions of second (conic) or third (cubic) order. By comparing the model predictions with the calibration values, the root-mean-square residuals for both the cubic and the conic functions were ∼50 μm for the aluminum thickness and ∼0.05 for the glandular ratio

  17. Compact radiometric microwave calibrator

    International Nuclear Information System (INIS)

    Fixsen, D. J.; Wollack, E. J.; Kogut, A.; Limon, M.; Mirel, P.; Singal, J.; Fixsen, S. M.

    2006-01-01

    The calibration methods for the ARCADE II instrument are described and the accuracy estimated. The Steelcast coated aluminum cones which comprise the calibrator have a low reflection while maintaining 94% of the absorber volume within 5 mK of the base temperature (modeled). The calibrator demonstrates an absorber with the active part less than one wavelength thick and only marginally larger than the mouth of the largest horn and yet black (less than -40 dB or 0.01% reflection) over five octaves in frequency

  18. Obtention of tumor volumes in PET images stacks using techniques of colored image segmentation

    International Nuclear Information System (INIS)

    Vieira, Jose W.; Lopes Filho, Ferdinand J.; Vieira, Igor F.

    2014-01-01

    This work demonstrated step by step how to segment color images of the chest of an adult in order to separate the tumor volume without significantly changing the values of the components R (Red), G (Green) and B (blue) of the colors of the pixels. For having information which allow to build color map you need to segment and classify the colors present at appropriate intervals in images. The used segmentation technique is to select a small rectangle with color samples in a given region and then erase with a specific color called 'rubber' the other regions of image. The tumor region was segmented into one of the images available and the procedure is displayed in tutorial format. All necessary computational tools have been implemented in DIP (Digital Image Processing), software developed by the authors. The results obtained, in addition to permitting the construction the colorful map of the distribution of the concentration of activity in PET images will also be useful in future work to enter tumors in voxel phantoms in order to perform dosimetric assessments

  19. Calibration uncertainty

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Anglov, Thomas

    2002-01-01

    Methods recommended by the International Standardization Organisation and Eurachem are not satisfactory for the correct estimation of calibration uncertainty. A novel approach is introduced and tested on actual calibration data for the determination of Pb by ICP-AES. The improved calibration...

  20. Utilizing a Multi-Source Forest Inventory Technique, MODIS Data and Landsat TM Images in the Production of Forest Cover and Volume Maps for the Terai Physiographic Zone in Nepal

    Directory of Open Access Journals (Sweden)

    Kalle Eerikäinen

    2012-12-01

    Full Text Available An approach based on the nearest neighbors techniques is presented for producing thematic maps of forest cover (forest/non-forest and total stand volume for the Terai region in southern Nepal. To create the forest cover map, we used a combination of Landsat TM satellite data and visual interpretation data, i.e., a sample grid of visual interpretation plots for which we obtained the land use classification according to the FAO standard. These visual interpretation plots together with the field plots for volume mapping originate from an operative forest inventory project, i.e., the Forest Resource Assessment of Nepal (FRA Nepal project. The field plots were also used in checking the classification accuracy. MODIS satellite data were used as a reference in a local correction approach conducted for the relative calibration of Landsat TM images. This study applied a non-parametric k-nearest neighbor technique (k-NN to the forest cover and volume mapping. A tree height prediction approach based on a nonlinear, mixed-effects (NLME modeling procedure is presented in the Appendix. The MODIS image data performed well as reference data for the calibration approach applied to make the Landsat image mosaic. The agreement between the forest cover map and the field observed values of forest cover was substantial in Western Terai (KHAT 0.745 and strong in Eastern Terai (KHAT 0.825. The forest cover and volume maps that were estimated using the k-NN method and the inventory data from the FRA Nepal project are already appropriate and valuable data for research purposes and for the planning of forthcoming forest inventories. Adaptation of the methods and techniques was carried out using Open Source software tools.

  1. Automatic anatomy partitioning of the torso region on CT images by using multiple organ localizations with a group-wise calibration technique

    Science.gov (United States)

    Zhou, Xiangrong; Morita, Syoichi; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2015-03-01

    This paper describes an automatic approach for anatomy partitioning on three-dimensional (3D) computedtomography (CT) images that divide the human torso into several volume-of-interesting (VOI) images based on anatomical definition. The proposed approach combines several individual detections of organ-location with a groupwise organ-location calibration and correction to achieve an automatic and robust multiple-organ localization task. The essence of the proposed method is to jointly detect the 3D minimum bounding box for each type of organ shown on CT images based on intra-organ-image-textures and inter-organ-spatial-relationship in the anatomy. Machine-learning-based template matching and generalized Hough transform-based point-distribution estimation are used in the detection and calibration processes. We apply this approach to the automatic partitioning of a torso region on CT images, which are divided into 35 VOIs presenting major organ regions and tissues required by routine diagnosis in clinical medicine. A database containing 4,300 patient cases of high-resolution 3D torso CT images is used for training and performance evaluations. We confirmed that the proposed method was successful in target organ localization on more than 95% of CT cases. Only two organs (gallbladder and pancreas) showed a lower success rate: 71 and 78% respectively. In addition, we applied this approach to another database that included 287 patient cases of whole-body CT images scanned for positron emission tomography (PET) studies and used for additional performance evaluation. The experimental results showed that no significant difference between the anatomy partitioning results from those two databases except regarding the spleen. All experimental results showed that the proposed approach was efficient and useful in accomplishing localization tasks for major organs and tissues on CT images scanned using different protocols.

  2. Development of a technique for the efficiency calibration of a HPGe detector for the off gas samples of a nuclear reactor

    International Nuclear Information System (INIS)

    Singh, Sarbjit; Agarwal, Chhavi; Ramaswami, A.; Manchanda, V.K.

    2007-01-01

    Regular monitoring of off gases released to the environment from a nuclear reactor is mandatory. The gaseous fission products are estimated by gamma ray spectrometry using a HPGe detector coupled to a multichannel analyser. In view of the lack of availability of gaseous fission products standards, an indirect method based on the charcoal absorption technique was developed for the efficiency calibration of HPGe detector system using 133B a and 152E u standards. The known activities of 133B a and 152E u are uniformly distributed in a vial having activated charcoal and counted on the HPGe detector system at liquid nitrogen temperature to determine the gamma ray efficiency for the vial having activated charcoal. The ratio of the gamma ray efficiencies of off gas present in the normal vial and the vial having activated charcoal at liquid nitrogen temperature are used to determine the gamma ray efficiency of off gas present in the normal vial. (author)

  3. Calibration of EBT2 film using a red-channel PDD method in combination with a modified three-channel technique

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Liyun, E-mail: liyunc@isu.edu.tw [Departments of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 82445, Taiwan (China); Ho, Sheng-Yow [Department of Nursing, Chang Jung Christian University, Tainan 73657, Taiwan and Department of Radiation Oncology, Chi Mei Medical Center, Liouying, Tainan 73657, Taiwan (China); Lee, Tsair-Fwu [Medical Physics and Informatics Laboratory, Department of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan (China); Yeh, Shyh-An [Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 82445, Taiwan and Department of Radiation Oncology, E-Da Hospital, Kaohsiung 82445, Taiwan (China); Ding, Hueisch-Jy [Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 82445, Taiwan (China); Chen, Pang-Yu, E-mail: pangyuchen@yahoo.com.tw [Department of Radiation Oncology, Sinlau Christian Hospital, Tainan 70142, Taiwan (China)

    2015-10-15

    Purpose: Ashland Inc. EBT2 and EBT3 films are widely used in quality assurance for radiation therapy; however, there remains a relatively high degree of uncertainty [B. Hartmann, M. Martisikova, and O. Jakel, “Homogeneity of Gafchromic EBT2 film,” Med. Phys. 37, 1753–1756 (2010)]. Micke et al. (2011) recently improved the spatial homogeneity using all color channels of a flatbed scanner; however, van Hoof et al. (2012) pointed out that the corrected nonuniformity still requires further investigation for larger fields. To reduce the calibration errors and the uncertainty, the authors propose a new red-channel percentage-depth-dose method in combination with a modified three-channel technique. Methods: For the ease of comparison, the EBT2 film image used in the authors’ previous study (2012) was reanalyzed using different approaches. Photon beams of 6-MV were delivered to two different films at two different beam on times, resulting in the absorption doses of ranging from approximately 30 to 300 cGy at the vertical midline of the film, which was set to be coincident with the central axis of the beam. The film was tightly sandwiched in a 30{sup 3}-cm{sup 3} polystyrene phantom, and the pixel values for red, green, and blue channels were extracted from 234 points on the central axis of the beam and compared with the corresponding depth doses. The film was first calibrated using the multichannel method proposed by Micke et al. (2010), accounting for nonuniformities in the scanner. After eliminating the scanner and dose-independent nonuniformities, the film was recalibrated via the dose-dependent optical density of the red channel and fitted to a power function. This calibration was verified via comparisons of the dose profiles extracted from the films, where three were exposed to a 60° physical wedge field and three were exposed to composite fields, and all of which were measured in a water phantom. A correction for optical attenuation was implemented, and

  4. Calibration of EBT2 film using a red-channel PDD method in combination with a modified three-channel technique

    International Nuclear Information System (INIS)

    Chang, Liyun; Ho, Sheng-Yow; Lee, Tsair-Fwu; Yeh, Shyh-An; Ding, Hueisch-Jy; Chen, Pang-Yu

    2015-01-01

    Purpose: Ashland Inc. EBT2 and EBT3 films are widely used in quality assurance for radiation therapy; however, there remains a relatively high degree of uncertainty [B. Hartmann, M. Martisikova, and O. Jakel, “Homogeneity of Gafchromic EBT2 film,” Med. Phys. 37, 1753–1756 (2010)]. Micke et al. (2011) recently improved the spatial homogeneity using all color channels of a flatbed scanner; however, van Hoof et al. (2012) pointed out that the corrected nonuniformity still requires further investigation for larger fields. To reduce the calibration errors and the uncertainty, the authors propose a new red-channel percentage-depth-dose method in combination with a modified three-channel technique. Methods: For the ease of comparison, the EBT2 film image used in the authors’ previous study (2012) was reanalyzed using different approaches. Photon beams of 6-MV were delivered to two different films at two different beam on times, resulting in the absorption doses of ranging from approximately 30 to 300 cGy at the vertical midline of the film, which was set to be coincident with the central axis of the beam. The film was tightly sandwiched in a 30 3 -cm 3 polystyrene phantom, and the pixel values for red, green, and blue channels were extracted from 234 points on the central axis of the beam and compared with the corresponding depth doses. The film was first calibrated using the multichannel method proposed by Micke et al. (2010), accounting for nonuniformities in the scanner. After eliminating the scanner and dose-independent nonuniformities, the film was recalibrated via the dose-dependent optical density of the red channel and fitted to a power function. This calibration was verified via comparisons of the dose profiles extracted from the films, where three were exposed to a 60° physical wedge field and three were exposed to composite fields, and all of which were measured in a water phantom. A correction for optical attenuation was implemented, and treatment

  5. A voxel-based technique to estimate the volume of trees from terrestrial laser scanner data

    Science.gov (United States)

    Bienert, A.; Hess, C.; Maas, H.-G.; von Oheimb, G.

    2014-06-01

    The precise determination of the volume of standing trees is very important for ecological and economical considerations in forestry. If terrestrial laser scanner data are available, a simple approach for volume determination is given by allocating points into a voxel structure and subsequently counting the filled voxels. Generally, this method will overestimate the volume. The paper presents an improved algorithm to estimate the wood volume of trees using a voxel-based method which will correct for the overestimation. After voxel space transformation, each voxel which contains points is reduced to the volume of its surrounding bounding box. In a next step, occluded (inner stem) voxels are identified by a neighbourhood analysis sweeping in the X and Y direction of each filled voxel. Finally, the wood volume of the tree is composed by the sum of the bounding box volumes of the outer voxels and the volume of all occluded inner voxels. Scan data sets from several young Norway maple trees (Acer platanoides) were used to analyse the algorithm. Therefore, the scanned trees as well as their representing point clouds were separated in different components (stem, branches) to make a meaningful comparison. Two reference measurements were performed for validation: A direct wood volume measurement by placing the tree components into a water tank, and a frustum calculation of small trunk segments by measuring the radii along the trunk. Overall, the results show slightly underestimated volumes (-0.3% for a probe of 13 trees) with a RMSE of 11.6% for the individual tree volume calculated with the new approach.

  6. Comprehensive inter-laboratory calibration of reference materials for δ18O versus VSMOW using various on-line high-temperature conversion techniques

    Science.gov (United States)

    Brand, Willi A.; Coplen, Tyler B.; Aerts-Bijma, Anita T.; Bohlke, John Karl; Gehre, Matthias; Geilmann, Heike; Groning, Manfred; Jansen, Henk G.; Meijer, Harro A. J.; Mroczkowski, Stanley J.; Qi, Haiping; Soergel, Karin; Stuart-Williams, Hilary; Weise, Stephan M.; Werner, Roland A.

    2009-01-01

    Internationally distributed organic and inorganic oxygen isotopic reference materials have been calibrated by six laboratories carrying out more than 5300 measurements using a variety of high-temperature conversion techniques (HTC) in an evaluation sponsored by the International Union of Pure and Applied Chemistry (IUPAC). To aid in the calibration of these reference materials, which span more than 125‰, an artificially enriched reference water (δ18O of +78.91‰) and two barium sulfates (one depleted and one enriched in 18O) were prepared and calibrated relative to VSMOW2 and SLAP reference waters. These materials were used to calibrate the other isotopic reference materials in this study, which yielded:Reference materialδ18O and estimated combined uncertainty IAEA-602 benzoic acid+71.28 ± 0.36‰USGS35 sodium nitrate+56.81 ± 0.31‰IAEA-NO-3 potassium nitrate+25.32 ± 0.29‰IAEA-601 benzoic acid+23.14 ± 0.19‰IAEA-SO-5 barium sulfate+12.13 ± 0.33‰NBS 127 barium sulfate+8.59 ± 0.26‰VSMOW2 water0‰IAEA-600 caffeine−3.48 ± 0.53‰IAEA-SO-6 barium sulfate−11.35 ± 0.31‰USGS34 potassium nitrate−27.78 ± 0.37‰SLAP water−55.5‰The seemingly large estimated combined uncertainties arise from differences in instrumentation and methodology and difficulty in accounting for all measurement bias. They are composed of the 3-fold standard errors directly calculated from the measurements and provision for systematic errors discussed in this paper. A primary conclusion of this study is that nitrate samples analyzed for δ18O should be analyzed with internationally distributed isotopic nitrates, and likewise for sulfates and organics. Authors reporting relative differences of oxygen-isotope ratios (δ18O) of nitrates, sulfates, or organic material should explicitly state in their reports the δ18O values of two or more internationally distributed nitrates (USGS34, IAEA-NO-3, and USGS35), sulfates (IAEA-SO-5, IAEA

  7. Calibration factor or calibration coefficient?

    International Nuclear Information System (INIS)

    Meghzifene, A.; Shortt, K.R.

    2002-01-01

    Full text: The IAEA/WHO network of SSDLs was set up in order to establish links between SSDL members and the international measurement system. At the end of 2001, there were 73 network members in 63 Member States. The SSDL network members provide calibration services to end-users at the national or regional level. The results of the calibrations are summarized in a document called calibration report or calibration certificate. The IAEA has been using the term calibration certificate and will continue using the same terminology. The most important information in a calibration certificate is a list of calibration factors and their related uncertainties that apply to the calibrated instrument for the well-defined irradiation and ambient conditions. The IAEA has recently decided to change the term calibration factor to calibration coefficient, to be fully in line with ISO [ISO 31-0], which recommends the use of the term coefficient when it links two quantities A and B (equation 1) that have different dimensions. The term factor should only be used for k when it is used to link the terms A and B that have the same dimensions A=k.B. However, in a typical calibration, an ion chamber is calibrated in terms of a physical quantity such as air kerma, dose to water, ambient dose equivalent, etc. If the chamber is calibrated together with its electrometer, then the calibration refers to the physical quantity to be measured per electrometer unit reading. In this case, the terms referred have different dimensions. The adoption by the Agency of the term coefficient to express the results of calibrations is consistent with the 'International vocabulary of basic and general terms in metrology' prepared jointly by the BIPM, IEC, ISO, OIML and other organizations. The BIPM has changed from factor to coefficient. The authors believe that this is more than just a matter of semantics and recommend that the SSDL network members adopt this change in terminology. (author)

  8. A technique for manual definition of an irregular volume of interest in single photon emission computed tomography

    International Nuclear Information System (INIS)

    Fleming, J.S.; Kemp, P.M.; Bolt, L.

    1999-01-01

    A technique is described for manually outlining a volume of interest (VOI) in a three-dimensional SPECT dataset. Regions of interest (ROIs) are drawn on three orthogonal maximum intensity projections. Image masks based on these ROIs are backprojected through the image volume and the resultant 3D dataset is segmented to produce the VOI. The technique has been successfully applied in the exclusion of unwanted areas of activity adjacent to the brain when segmenting the organ in SPECT imaging using 99m Tc HMPAO. An example of its use for segmentation in tumour imaging is also presented. The technique is of value for applications involving semi-automatic VOI definition in SPECT. (author)

  9. In-Vitro gas production technique as for feed evaluation: volume of gas production and feed degradability

    International Nuclear Information System (INIS)

    Asih Kurniawati

    2007-01-01

    In-vitro gas production technique can be used to predict feed quality. The effect of molasses supplementation as a source of degradable carbohydrate to protein source red clover silage has been done using this technique. Data showed there were positive correlation between total volume gas produced and feed degradability (r = 0.96), between total volume gas produced and microbial biomass (r = 0,96). Dry matter degradability, dry matter degraded, microbial biomass production and efficiency of nitrogen utilization, highly significant (P<0,01) increased due to increasing of degradable carbohydrate. The addition of 0.3 g molasses gave the best result whereas the addition of 0.15 g and 0.225 g have better effect than 0.0625 g molasses addition and red clover only. This result suggested that In-vitro production technique can be used as tool for feed evaluation. (author)

  10. Semipermanent Volumization by an Absorbable Filler: Onlay Injection Technique to the Bone

    Directory of Open Access Journals (Sweden)

    Takanobu Mashiko, MD

    2013-04-01

    Conclusions: Semipermanent volumizing effects can be achieved by HA injection if the target area has an underlying bony floor. Periosteal stem cells may be activated by HA injection and may contribute to persistent volumizing effects. This treatment may be a much less invasive alternative to fat or bone grafting.

  11. A comparative study of surface- and volume-based techniques for the automatic registration between CT and SPECT brain images

    International Nuclear Information System (INIS)

    Kagadis, George C.; Delibasis, Konstantinos K.; Matsopoulos, George K.; Mouravliansky, Nikolaos A.; Asvestas, Pantelis A.; Nikiforidis, George C.

    2002-01-01

    Image registration of multimodality images is an essential task in numerous applications in three-dimensional medical image processing. Medical diagnosis can benefit from the complementary information in different modality images. Surface-based registration techniques, while still widely used, were succeeded by volume-based registration algorithms that appear to be theoretically advantageous in terms of reliability and accuracy. Several applications of such algorithms for the registration of CT-MRI, CT-PET, MRI-PET, and SPECT-MRI images have emerged in the literature, using local optimization techniques for the matching of images. Our purpose in this work is the development of automatic techniques for the registration of real CT and SPECT images, based on either surface- or volume-based algorithms. Optimization is achieved using genetic algorithms that are known for their robustness. The two techniques are compared against a well-established method, the Iterative Closest Point--ICP. The correlation coefficient was employed as an independent measure of spatial match, to produce unbiased results. The repeated measures ANOVA indicates the significant impact of the choice of registration method on the magnitude of the correlation (F=4.968, p=0.0396). The volume-based method achieves an average correlation coefficient value of 0.454 with a standard deviation of 0.0395, as opposed to an average of 0.380 with a standard deviation of 0.0603 achieved by the surface-based method and an average of 0.396 with a standard deviation equal to 0.0353 achieved by ICP. The volume-based technique performs significantly better compared to both ICP (p<0.05, Neuman Keuls test) and the surface-based technique (p<0.05, Neuman-Keuls test). Surface-based registration and ICP do not differ significantly in performance

  12. Estimates of soil erosion and deposition of cultivated soil of Nakhla watershed, Morocco, using 137Cs technique and calibration models

    International Nuclear Information System (INIS)

    Bouhlassa, S.; Moukhchane, M.; Aiachi, A.

    2000-01-01

    Despite the effective threat of erosion, for soil preservation and productivity in Morocco, there is still only limited information on rates of soil loss involved. This study is aimed to establish long-term erosion rates on cultivated land in the Nakhla watershed located in the north of the country, using 137 Cs technique. Two sampling strategies were adopted. The first is aimed at establishing areal estimates of erosion, whereas the second, based on a transect approach, intends to determine point erosion. Twenty-one cultivated sites and seven undisturbed sites apparently not affected by erosion or deposition were sampled to 35 cm depth. Nine cores were collected along the transect of 149 m length. The assessment of erosion rates with models varying in complexity from the simple Proportional Model to more complex Mass Balance Models which attempts to include the processes controlling the redistribution of 137 Cs in soil, enables us to demonstrate the significance of soil erosion problem on cultivated land. Erosion rates rises up to 50 t ha -1 yr -1 . The 137 Cs derived erosion rates provide a reliable representation of water erosion pattern in the area, and indicate the importance of tillage process on the redistribution of 137 Cs in soil. For aggrading sites a Constant Rate Supply (CRS) Model had been adapted and introduced to estimate easily the depositional rate. (author) [fr

  13. Usefulness of PC based 3D volume rendering technique in the evaluation of suspected aneurysm on brain MRA

    International Nuclear Information System (INIS)

    Baek, Seung Il; Lee, Ghi Jai; Shim, Jae Chan; Bang, Sun Woo; Ryu, Seok Jong; Kim, Ho Kyun

    2002-01-01

    To evaluated usefulness of volume rending technique using 3D visualization software on PC in patients with suspected intracranial aneurysm on brain MRA. We analyzed prospectively 21 patients with suspected aneurysms on the routine MIP images which were obtained 15 .deg. C increment along axial and sagittal plane, among 135 patients in whom brain MRA was done due to stroke symptoms for recent 5 months. The locations were the anterior communicating artery (A-com) in 8 patients, the posterior communicating artery (P-com) in 3, the ICA bifurcation in 5, the MCA bifurcation in 4, and the basilar tip in one. Male to female ratio was 14:7 and mean age was 62 years. MRA source images were sent to PC through LAN, and the existence of aneurysm was evaluated with volume rendering technique using 3D visualization software on PC. The presence or absence of aneurysm on MIP and volume rendering images was decided by the consensus of two radiologists. We found the aneurysms with volume rendering technique, from 1 patient among 8 patients with suspected aneurysm at A-com and also 1 patient among 3 patients with suspected aneurysm at P=com on routine MIP images. Confirmative angiography and interventional procedures were done in these 2 patients. The causes for mimicking the aneurysm on MIP were flow displacement artifact in 9, normal P-com infundibulum in 2, and overlapped or narrowed vessels in 8 patients, and among them confirmative angiography was done in 2 patient. Volume rendering technique using visualization software on PC is useful to scrutinize the suspected aneurysm on routine MIP images and to avoid further invasive angiography

  14. Significance of left ventricular volume measurement after heart transplantation using radionuclide techniques

    International Nuclear Information System (INIS)

    Novitzky, D.; Cooper, D.; Boniaszczuk, J.

    1985-01-01

    Multigated equilibrium blood pool scanning using Technetium 99m labeled red blood cells was used to measure left ventricular volumes in three heterotopic and one orthotopic heart transplant recipient(s). Simultaneously, an endomyocardial biopsy was performed and the degree of acute rejection was assessed by a histological scoring system. The scores were correlated to changes in ejection fraction and heart rate. Technetium 99m scanning data were pooled according to the endomyocardial biopsy score: no rejection; mild rejection; moderate rejection, and severe rejection. In each group, the median of the left ventricular volume parameters was calculated and correlated with the endomyocardial biopsy score, using a non-parametric one-way analysis of variance. A decrease in stroke volume correlated best with the endomyocardial biopsy score during acute rejection. A decrease in end-diastolic left ventricular volumes did not correlate as well. Changes in the end-systolic left ventricular volumes were not statistically significant, but using a simple correlation between end-systolic left ventricular volumes and endomyocardial biopsy the correlation reached significance. Changes in left ventricular volumes measured by Technetium 99m scanning may be useful to confirm the presence or absence of acute rejection in patients with heart grafts

  15. A novel 3D volumetric voxel registration technique for volume-view-guided image registration of multiple imaging modalities

    International Nuclear Information System (INIS)

    Li Guang; Xie Huchen; Ning, Holly; Capala, Jacek; Arora, Barbara C.; Coleman, C. Norman; Camphausen, Kevin; Miller, Robert W.

    2005-01-01

    Purpose: To provide more clinically useful image registration with improved accuracy and reduced time, a novel technique of three-dimensional (3D) volumetric voxel registration of multimodality images is developed. Methods and Materials: This technique can register up to four concurrent images from multimodalities with volume view guidance. Various visualization effects can be applied, facilitating global and internal voxel registration. Fourteen computed tomography/magnetic resonance (CT/MR) image sets and two computed tomography/positron emission tomography (CT/PET) image sets are used. For comparison, an automatic registration technique using maximization of mutual information (MMI) and a three-orthogonal-planar (3P) registration technique are used. Results: Visually sensitive registration criteria for CT/MR and CT/PET have been established, including the homogeneity of color distribution. Based on the registration results of 14 CT/MR images, the 3D voxel technique is in excellent agreement with the automatic MMI technique and is indicatory of a global positioning error (defined as the means and standard deviations of the error distribution) using the 3P pixel technique: 1.8 deg ± 1.2 deg in rotation and 2.0 ± 1.3 (voxel unit) in translation. To the best of our knowledge, this is the first time that such positioning error has been addressed. Conclusion: This novel 3D voxel technique establishes volume-view-guided image registration of up to four modalities. It improves registration accuracy with reduced time, compared with the 3P pixel technique. This article suggests that any interactive and automatic registration should be safeguarded using the 3D voxel technique

  16. Studies in Fat Grafting: Part I. Effects of Injection Technique on in vitro Fat Viability and in vivo Volume Retention

    Science.gov (United States)

    Chung, Michael T.; Paik, Kevin J.; Atashroo, David A.; Hyun, Jeong S.; McArdle, Adrian; Senarath-Yapa, Kshemendra; Zielins, Elizabeth R.; Tevlin, Ruth; Duldulao, Chris; Hu, Michael S.; Walmsley, Graham G.; Parisi-Amon, Andreina; Momeni, Arash; Rimsa, Joe R.; Commons, George W.; Gurtner, Geoffrey C.; Wan, Derrick C.; Longaker, Michael T.

    2014-01-01

    Background Fat grafting has become increasingly popular for the correction of soft tissue deficits at many sites throughout the body. Long-term outcomes, however, depend on delivery of fat in the least traumatic fashion to optimize viability of the transplanted tissue. In this study, we compare the biologic properties of fat following injection using two methods. Methods Lipoaspiration samples were obtained from five female donors and cellular viability, proliferation, and lipolysis were evaluated following injection using either a modified Coleman technique or an automated, low shear device. Comparisons were made to minimally processed, uninjected fat. Volume retention was also measured over twelve weeks following injection of fat under the scalp of immunodeficient mice using either the modified Coleman technique or the Adipose Tissue Injector. Finally, fat grafts were analyzed histologically. Results Fat viability and cellular proliferation were both significantly greater with the Adipose Tissue Injector relative to injection with the modified Coleman technique. In contrast, significantly less lipolysis was noted using the automated device. In vivo fat volume retention was significantly greater than with the modified Coleman technique at 4, 6, 8, and 12 week time points. This corresponded with significantly greater histological scores for healthy fat and lower scores for injury following injection with the device. Conclusions Biological properties of injected tissues reflect how disruptive and harmful techniques for placement of fat may be, and our in vitro and in vivo data both support the use of the automated, low shear devices compared to the modified Coleman technique. PMID:24622574

  17. Calibration of Correlation Radiometers Using Pseudo-Random Noise Signals

    Directory of Open Access Journals (Sweden)

    Sebastián Pantoja

    2009-08-01

    Full Text Available The calibration of correlation radiometers, and particularly aperture synthesis interferometric radiometers, is a critical issue to ensure their performance. Current calibration techniques are based on the measurement of the cross-correlation of receivers’ outputs when injecting noise from a common noise source requiring a very stable distribution network. For large interferometric radiometers this centralized noise injection approach is very complex from the point of view of mass, volume and phase/amplitude equalization. Distributed noise injection techniques have been proposed as a feasible alternative, but are unable to correct for the so-called “baseline errors” associated with the particular pair of receivers forming the baseline. In this work it is proposed the use of centralized Pseudo-Random Noise (PRN signals to calibrate correlation radiometers. PRNs are sequences of symbols with a long repetition period that have a flat spectrum over a bandwidth which is determined by the symbol rate. Since their spectrum resembles that of thermal noise, they can be used to calibrate correlation radiometers. At the same time, since these sequences are deterministic, new calibration schemes can be envisaged, such as the correlation of each receiver’s output with a baseband local replica of the PRN sequence, as well as new distribution schemes of calibration signals. This work analyzes the general requirements and performance of using PRN sequences for the calibration of microwave correlation radiometers, and particularizes the study to a potential implementation in a large aperture synthesis radiometer using an optical distribution network.

  18. Principles and techniques of radiation hardening. Volume 3. Electromagnetic pulse (EMP) and system generated EMP

    International Nuclear Information System (INIS)

    Rudie, N.J.

    1976-01-01

    The three-volume book is intended to serve as a review of the effects of thermonuclear explosion induced radiation (x-rays, gamma rays, and beta particles) and the resulting electromagnetic pulse (EMP). Volume 3 deals with the following topics: selected fundamentals of electromagnetic theory; EMP induced currents on antennas and cables; the EMP response of electronics; EMP hardening; EMP testing; injection currents; internal electromagnetic pulse (IEMP); replacement currents; and system generated electromagnetic pulse (SGEMP) hardening

  19. Nirex 97 an assessment of the post-closure performance of a deep waste repository at Sellafield. Volume 2; hydrogeological conceptual model development - effective parameters and calibration appendix

    International Nuclear Information System (INIS)

    Jackson, C.; Watson, S.

    1997-01-01

    repository zone beneath Longlands Farm. In style, scope and presentation, Nirex 97 is primarily aimed at the scientific community, other radioactive waste disposal agencies and regulators. The report is published as part of Nirex's commitment to open publication of its scientific findings. The main value of the report currently is as a demonstration of the generic capability which has been developed to assess the radiological safety performance of candidate repository sites. The safety assessment reported as Nirex 97 was carried out between April 1996 and August 1997. It updates a preliminary assessment of the groundwater pathway for a repository at Sellafield, 'Nirex 95' published in July 1995. Nirex 97 takes account of further data obtained from the Nirex waste inventory, design, site characterisation and research programmes. In addition, Nirex 97 extends the Nirex 95 evaluation to include consideration of the potential radiological and flammability hazards in the biosphere arising from the effects of gas generation within the repository and the extent of pressurisation within the repository vaults. The assessment also takes account of the latest guidance from the Environment Agencies on requirements for authorisation of disposal facilities on land. Volume 2: Hydrogeological Model Development - Effective Parameters and Calibration, explains the steps followed to interpret and process field data in order to build a variety of two- and three-dimensional numerical models of groundwater flow. It describes the process of upscaling used to derive effective hydrogeological parameters for the hydrogeological units represented in these numerical models. The calibration of these numerical models is discussed

  20. Nirex 97 an assessment of the post-closure performance of a deep waste repository at Sellafield. Volume 2; hydrogeological conceptual model development - effective parameters and calibration

    International Nuclear Information System (INIS)

    Jackson, C.; Watson, S.

    1997-01-01

    repository zone beneath Longlands Farm. In style, scope and presentation, Nirex 97 is primarily aimed at the scientific community, other radioactive waste disposal agencies and regulators. The report is published as part of Nirex's commitment to open publication of its scientific findings. The main value of the report currently is as a demonstration of the generic capability which has been developed to assess the radiological safety performance of candidate repository sites. The safety assessment reported as Nirex 97 was carried out between April 1996 and August 1997. It updates a preliminary assessment of the groundwater pathway for a repository at Sellafield, 'Nirex 95' published in July 1995. Nirex 97 takes account of further data obtained from the Nirex waste inventory, design, site characterisation and research programmes. In addition, Nirex 97 extends the Nirex 95 evaluation to include consideration of the potential radiological and flammability hazards in the biosphere arising from the effects of gas generation within the repository and the extent of pressurisation within the repository vaults. The assessment also takes account of the latest guidance from the Environment Agencies on requirements for authorisation of disposal facilities on land. Volume 2: Hydrogeological Model Development - Effective Parameters and Calibration, explains the steps followed to interpret and process field data in order to build a variety of two- and three-dimensional numerical models of groundwater flow. It describes the process of upscaling used to derive effective hydrogeological parameters for the hydrogeological units represented in these numerical models. The calibration of these numerical models is discussed

  1. 3D CT cerebral angiography technique using a 320-detector machine with a time–density curve and low contrast medium volume: Comparison with fixed time delay technique

    International Nuclear Information System (INIS)

    Das, K.; Biswas, S.; Roughley, S.; Bhojak, M.; Niven, S.

    2014-01-01

    Aim: To describe a cerebral computed tomography angiography (CTA) technique using a 320-detector CT machine and a small contrast medium volume (35 ml, 15 ml for test bolus). Also, to compare the quality of these images with that of the images acquired using a larger contrast medium volume (90 or 120 ml) and a fixed time delay (FTD) of 18 s using a 16-detector CT machine. Materials and methods: Cerebral CTA images were acquired using a 320-detector machine by synchronizing the scanning time with the time of peak enhancement as determined from the time–density curve (TDC) using a test bolus dose. The quality of CTA images acquired using this technique was compared with that obtained using a FTD of 18 s (by 16-detector CT), retrospectively. Average densities in four different intracranial arteries, overall opacification of arteries, and the degree of venous contamination were graded and compared. Results: Thirty-eight patients were scanned using the TDC technique and 40 patients using the FTD technique. The arterial densities achieved by the TDC technique were higher (significant for supraclinoid and basilar arteries, p < 0.05). The proportion of images deemed as having “good” arterial opacification was 95% for TDC and 90% for FTD. The degree of venous contamination was significantly higher in images produced by the FTD technique (p < 0.001%). Conclusion: Good diagnostic quality CTA images with significant reduction of venous contamination can be achieved with a low contrast medium dose using a 320-detector machine by coupling the time of data acquisition with the time of peak enhancement

  2. Improvement of Railroad Roller Bearing Test Procedures & Development of Roller Bearing Diagnostic Techniques. Volume 2.

    Science.gov (United States)

    1982-04-01

    A comprehensive review of existing basic diagnostic techniques applicable to the railcar roller bearing defect and failure problem was made. Of the potentially feasible diagnostic techniques identified, high frequency vibration was selected for exper...

  3. Classification of high-resolution multi-swath hyperspectral data using Landsat 8 surface reflectance data as a calibration target and a novel histogram based unsupervised classification technique to determine natural classes from biophysically relevant fit parameters

    Science.gov (United States)

    McCann, C.; Repasky, K. S.; Morin, M.; Lawrence, R. L.; Powell, S. L.

    2016-12-01

    Compact, cost-effective, flight-based hyperspectral imaging systems can provide scientifically relevant data over large areas for a variety of applications such as ecosystem studies, precision agriculture, and land management. To fully realize this capability, unsupervised classification techniques based on radiometrically-calibrated data that cluster based on biophysical similarity rather than simply spectral similarity are needed. An automated technique to produce high-resolution, large-area, radiometrically-calibrated hyperspectral data sets based on the Landsat surface reflectance data product as a calibration target was developed and applied to three subsequent years of data covering approximately 1850 hectares. The radiometrically-calibrated data allows inter-comparison of the temporal series. Advantages of the radiometric calibration technique include the need for minimal site access, no ancillary instrumentation, and automated processing. Fitting the reflectance spectra of each pixel using a set of biophysically relevant basis functions reduces the data from 80 spectral bands to 9 parameters providing noise reduction and data compression. Examination of histograms of these parameters allows for determination of natural splitting into biophysical similar clusters. This method creates clusters that are similar in terms of biophysical parameters, not simply spectral proximity. Furthermore, this method can be applied to other data sets, such as urban scenes, by developing other physically meaningful basis functions. The ability to use hyperspectral imaging for a variety of important applications requires the development of data processing techniques that can be automated. The radiometric-calibration combined with the histogram based unsupervised classification technique presented here provide one potential avenue for managing big-data associated with hyperspectral imaging.

  4. Spatial and temporal single-cell volume estimation by a fluorescence imaging technique with application to astrocytes in primary culture

    Science.gov (United States)

    Khatibi, Siamak; Allansson, Louise; Gustavsson, Tomas; Blomstrand, Fredrik; Hansson, Elisabeth; Olsson, Torsten

    1999-05-01

    Cell volume changes are often associated with important physiological and pathological processes in the cell. These changes may be the means by which the cell interacts with its surrounding. Astroglial cells change their volume and shape under several circumstances that affect the central nervous system. Following an incidence of brain damage, such as a stroke or a traumatic brain injury, one of the first events seen is swelling of the astroglial cells. In order to study this and other similar phenomena, it is desirable to develop technical instrumentation and analysis methods capable of detecting and characterizing dynamic cell shape changes in a quantitative and robust way. We have developed a technique to monitor and to quantify the spatial and temporal volume changes in a single cell in primary culture. The technique is based on two- and three-dimensional fluorescence imaging. The temporal information is obtained from a sequence of microscope images, which are analyzed in real time. The spatial data is collected in a sequence of images from the microscope, which is automatically focused up and down through the specimen. The analysis of spatial data is performed off-line and consists of photobleaching compensation, focus restoration, filtering, segmentation and spatial volume estimation.

  5. Pulsed neutron activation calibration technique

    International Nuclear Information System (INIS)

    Kehler, P.

    1979-01-01

    A pulsed neutron activation (PNA) for measurement of two-phase flow consists of a pulsed source of fast neutron to activate the oxygen in a steam-water mixture. Flow is measured downstream by an NaI detector. Measured counts are sorted by a multiscaler into different time channels. A counts vs. time distribution typical for two-phase flow with slip between the two phases is obtained. Proper evaluation for the counts/time distribution leads to flow-regime independent equations for the average of the inverse transil time and the average density. After calculation of the average mass flow velocity, the true mass flow is derived

  6. Estimation of free volumes of polystyrene by positron annihilation life-time technique

    International Nuclear Information System (INIS)

    Li, Hong-Ling; Ujihira, Yusuke; Nanasawa, Atsushi.

    1996-01-01

    Differences of size, content, and size distribution of free volumes in linear and three-armed polystyrenes, synthesized by radical, and anionic processes, were observed by positron annihilation lifetime measurements. For the polystyrene samples of different architectures and molecular weight distributions, the temperature dependence of an average free volume radius was quite similar to each other. The radius increased with increasing temperature (T), from 0.27 nm (60 K) to 0.30 nm (glass transition temperature: T g = 363 K), then to 0.35 nm (423 K), showing αβ transition temperature about 300 K. With increasing T, the free volume content decreased from 35% (60 K) to 25% (260 K) for radically polymerized linear polystyrene and to 22% (320 K) for anionically polymerized three-armed polystyrene, and then turned to increase to 35% at 350 K and 400 K, respectively. In contrast, the content for anionically polymerized linear polystyrene decreased from 45% (60 K) to 33% (300 K) and turned to increase to 35% at 350-400 K. The free volume content decreased reciprocally with an increase in the molecular weight at 333 K, suggesting differences in molecular motion between the edge and middle portions of the chain molecule. (author)

  7. Radiation Calibration Measurements

    International Nuclear Information System (INIS)

    Omondi, C.

    2017-01-01

    KEBS Radiation Dosimetry mandate are: Custodian of Kenya Standards on Ionizing radiation, Ensure traceability to International System (SI ) and Calibration radiation equipment. RAF 8/040 on Radioisotope applications for troubleshooting and optimizing industrial process established Radiotracer Laboratory objective is to introduce and implement radiotracer technique for problem solving of industrial challenges. Gamma ray scanning technique applied is to Locate blockages, Locate liquid in vapor lines, Locate areas of lost refractory or lining in a pipe and Measure flowing densities. Equipment used for diagnostic and radiation protection must be calibrated to ensure Accuracy and Traceability

  8. SPOTS Calibration Example

    Directory of Open Access Journals (Sweden)

    Patterson E.

    2010-06-01

    Full Text Available The results are presented using the procedure outlined by the Standardisation Project for Optical Techniques of Strain measurement to calibrate a digital image correlation system. The process involves comparing the experimental data obtained with the optical measurement system to the theoretical values for a specially designed specimen. The standard states the criteria which must be met in order to achieve successful calibration, in addition to quantifying the measurement uncertainty in the system. The system was evaluated at three different displacement load levels, generating strain ranges from 289 µstrain to 2110 µstrain. At the 289 µstrain range, the calibration uncertainty was found to be 14.1 µstrain, and at the 2110 µstrain range it was found to be 28.9 µstrain. This calibration procedure was performed without painting a speckle pattern on the surface of the metal. Instead, the specimen surface was prepared using different grades of grit paper to produce the desired texture.

  9. Fractional filling with the microdepot technique as an alternative to bolus hyaluronic acid injections in facial volume restoration.

    Science.gov (United States)

    Lim, Adrian C; Lowe, Patricia M

    2011-05-01

    For volume restoration of the face, hyaluronic acid is conventionally injected through long, large-bore, 18-gauge needles because of the higher viscosity subtypes required. These hyaluronic acids are either more highly cross-linked or larger in particle size than the less-viscous subtypes. The microdepot injection technique involves using the 31-gauge BD insulin syringe (Becton-Dickinson, North Ryde, NSW Australia) to deposit small amounts of filler (0.05-0.1 mL) throughout the area of volume loss. The procedure is extremely well tolerated, requiring only topical and ice anaesthesia. Using this method, volume restoration can be achieved naturally and progressively over a period of time. Fractional filling every 3-4 months is continued until the desired level of volume correction is attained. Patients undergoing fractional filling followed over a 12-month period did not indicate any observable compromise in filler longevity, even when highly viscous hyaluronic acid fillers were injected through small-bore, 31-gauge insulin syringes. © 2011 The Authors. Australasian Journal of Dermatology © 2011 The Australasian College of Dermatologists.

  10. Cardiac chamber volumes by echocardiography using a new mathematical method: A promising technique for zero-G use

    Science.gov (United States)

    Buckey, J. C.; Beattie, J. M.; Gaffney, F. A.; Nixon, J. V.; Blomqvist, C. G.

    1984-01-01

    Accurate, reproducible, and non-invasive means for ventricular volume determination are needed for evaluating cardiovascular function zero-gravity. Current echocardiographic methods, particularly for the right ventricle, suffer from a large standard error. A new mathematical approach, recently described by Watanabe et al., was tested on 1 normal formalin-fixed human hearts suspended in a mineral oil bath. Volumes are estimated from multiple two-dimensional echocardiographic views recorded from a single point at sequential angles. The product of sectional cavity area and center of mass for each view summed over the range of angles (using a trapezoidal rule) gives volume. Multiple (8-14) short axis right ventricle and left ventricle views at 5.0 deg intervals were videotaped. The images were digitized by two independent observers (leading-edge to leading-edge technique) and analyzed using a graphics tablet and microcomputer. Actual volumes were determined by filling the chambers with water. These data were compared to the mean of the two echo measurements.

  11. Proceedings of the National Conference on Energy Resource Management. Volume 1: Techniques, Procedures and Data Bases

    Science.gov (United States)

    Brumfield, J. O. (Editor); Schiffman, Y. M. (Editor)

    1982-01-01

    Topics dealing with the integration of remotely sensed data with geographic information system for application in energy resources management are discussed. Associated remote sensing and image analysis techniques are also addressed.

  12. SU-G-TeP4-03: A Multileaf Collimator Calibration and Quality Assurance Technique Using An Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Lebron, S; Yan, G; Li, J; Lu, B; Liu, C [University of Florida, Gainesville, FL (United States)

    2016-06-15

    Purpose: To develop an accurate and quick multileaf collimator (MLC) calibration and quality assurance technique using an electronic portal imaging device (EPID) Methods: The MLC models used include the MLCi and Agility (Elekta Ltd). This technique consists of two 22(L)x10(W) cm{sup 2} fields with 0{sup 0} and 180{sup 0} collimator angles centered to an offset EPID. The MLC opening is estimated by calculating the profile at the image’s center in the image’s horizontal direction. Scans in the image’s vertical direction were calculated every 20 pixels in the inner 70% of estimated MLC opening. The profiles’ edges were fitted with linear equations to determine the image’s rotation angle. Then, crossline profiles were scanned at the center of each leaf taking into account the leaf’s width at isocenter and the rotation angle. The profiles’ edges determine the location of the leaves’ edges and these were subtracted from the reference leaf’s position in order to determine the relative leaf offsets. The edge location of all profiles was determined by using the parameterized gradient of the penumbra region. The technique was tested against an established diode array-based method, and for different MLC systems, patterns, gantry angles, days, energies, beam modalities and MLC openings. Results: The differences between the proposed and established methods were 0.26±0.19mm. The leaf offsets’ deviation was <0.3mm (5 months period). For pattern fields, the differences between predetermined and calculated offsets were 0.18±0.18mm. The leaf offset deviation of measurements with different energies and MLC openings were <0.1mm and <0.3mm, respectively. The differences between offsets of FF and FFF beams were 0.01±0.02mm (<0.07mm). The differences between the offsets at different gantry angles were 0.08±0.15mm. Conclusion: The proposed method proved to be accurate and efficient in calculating the relative leaf offsets. Parameterized field edge is essential to

  13. Stereological estimates of nuclear volume and other quantitative variables in supratentorial brain tumors. Practical technique and use in prognostic evaluation

    DEFF Research Database (Denmark)

    Sørensen, Flemming Brandt; Braendgaard, H; Chistiansen, A O

    1991-01-01

    The use of morphometry and modern stereology in malignancy grading of brain tumors is only poorly investigated. The aim of this study was to present these quantitative methods. A retrospective feasibility study of 46 patients with supratentorial brain tumors was carried out to demonstrate...... the practical technique. The continuous variables were correlated with the subjective, qualitative WHO classification of brain tumors, and the prognostic value of the parameters was assessed. Well differentiated astrocytomas (n = 14) had smaller estimates of the volume-weighted mean nuclear volume and mean...... nuclear profile area, than those of anaplastic astrocytomas (n = 13) (2p = 3.1.10(-3) and 2p = 4.8.10(-3), respectively). No differences were seen between the latter type of tumor and glioblastomas (n = 19). The nuclear index was of the same magnitude in all three tumor types, whereas the mitotic index...

  14. A technique of using gated-CT images to determine internal target volume (ITV) for fractionated stereotactic lung radiotherapy

    International Nuclear Information System (INIS)

    Jin Jianyue; Ajlouni, Munther; Chen Qing; Yin, Fang-Fang; Movsas, Benjamin

    2006-01-01

    Background and purpose: To develop and evaluate a technique and procedure of using gated-CT images in combination with PET image to determine the internal target volume (ITV), which could reduce the planning target volume (PTV) with adequate target coverage. Patients and methods: A skin marker-based gating system connected to a regular single slice CT scanner was used for this study. A motion phantom with adjustable motion amplitude was used to evaluate the CT gating system. Specifically, objects of various sizes/shapes, considered as virtual tumors, were placed on the phantom to evaluate the number of phases of gated images required to determine the ITV while taking into account tumor size, shape and motion. A procedure of using gated-CT and PET images to define ITV for patients was developed and was tested in patients enrolled in an IRB approved protocol. Results: The CT gating system was capable of removing motion artifacts for target motion as large as 3-cm when it was gated at optimal phases. A phantom study showed that two gated-CT scans at the end of expiration and the end of inspiration would be sufficient to determine the ITV for tumor motion less than 1-cm, and another mid-phase scan would be required for tumors with 2-cm motion, especially for small tumors. For patients, the ITV encompassing visible tumors in all sets of gated-CT and regular spiral CT images seemed to be consistent with the target volume determined from PET images. PTV expanded from the ITV with a setup uncertainty margin had less volume than PTVs from spiral CT images with a 10-mm generalized margin or an individualized margin determined at fluoroscopy. Conclusions: A technique of determining the ITV using gated-CT images was developed and was clinically implemented successfully for fractionated stereotactic lung radiotherapy

  15. Hemodynamic stability ensured by a low dose, low volume, unilateral hypobaric spinal block: modification of a technique.

    Science.gov (United States)

    Elzinga, L; Marcus, M; Peek, D; Borg, P; Jansen, J; Koster, J; Enk, D

    2009-01-01

    We report the case of an 89-year-old female with a history of arterial hypertension, intermittent rapid atrial fibrillation and severe aortic valve stenosis, suffering from femoral neck fracture. Hyperbaric unilateral spinal anesthesia is a known technique to obtain stable hemodynamics combined with the possibility of continuous neurologic evaluation and preservation of cognitive functions. Because a hyperbaric unilateral technique can be very painful in case of traumatic hip fracture, a low dose, low volume, unilateral hypobaric spinal block may be an adequate alternative. In the present case report, a unilateral hypobaric spinal anesthesia was performed using 5 mg of bupivacaine in a 1.5 mL volume and a slow and steady, "air-buffered", directed injection technique, to allow an urgent hip arthroplasty. During surgery the patient was kept in the lateral recumbent position. Hemodynamics remained stable throughout the entire procedure without any need for vasoconstrictors. The impact of aortic valve stenosis combined with atrial fibrillation on anesthetic management and our considerations to opt for a unilateral hypobaric spinal anesthesia are discussed.

  16. Cross-calibration of interferometric SAR data

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2003-01-01

    Generation of digital elevation models from interferometric synthetic aperture radar (SAR) data is a well established technique. Achieving a high geometric fidelity calls for a calibration accounting for inaccurate navigation data and system parameters as well as system imperfections. Fully...... automated calibration techniques are preferable, especially for operational mapping. The author presents one such technique, called cross-calibration. Though developed for single-pass interferometry, it may be applicable to multi-pass interferometry, too. Cross-calibration requires stability during mapping...... ground control point is often needed. The paper presents the principles and mathematics of the cross-calibration technique and illustrates its successful application to EMISAR data....

  17. A Novel Technique for Endovascular Removal of Large Volume Right Atrial Tumor Thrombus

    Energy Technology Data Exchange (ETDEWEB)

    Nickel, Barbara, E-mail: nickel.ba@gmail.com [US Teleradiology and Quantum Medical Radiology Group (United States); McClure, Timothy, E-mail: tmcclure@gmail.com; Moriarty, John, E-mail: jmoriarty@mednet.ucla.edu [UCLA Medical Center, Department of Interventional Radiology (United States)

    2015-08-15

    Venous thromboembolic disease is a significant cause of morbidity and mortality, particularly in the setting of large volume pulmonary embolism. Thrombolytic therapy has been shown to be a successful treatment modality; however, its use somewhat limited due to the risk of hemorrhage and potential for distal embolization in the setting of large mobile thrombi. In patients where either thrombolysis is contraindicated or unsuccessful, and conventional therapies prove inadequate, surgical thrombectomy may be considered. We present a case of percutaneous endovascular extraction of a large mobile mass extending from the inferior vena cava into the right atrium using the Angiovac device, a venovenous bypass system designed for high-volume aspiration of undesired endovascular material. Standard endovascular methods for removal of cancer-associated thrombus, such as catheter-directed lysis, maceration, and exclusion, may prove inadequate in the setting of underlying tumor thrombus. Where conventional endovascular methods either fail or are unsuitable, endovascular thrombectomy with the Angiovac device may be a useful and safe minimally invasive alternative to open resection.

  18. A Novel Technique for Endovascular Removal of Large Volume Right Atrial Tumor Thrombus

    International Nuclear Information System (INIS)

    Nickel, Barbara; McClure, Timothy; Moriarty, John

    2015-01-01

    Venous thromboembolic disease is a significant cause of morbidity and mortality, particularly in the setting of large volume pulmonary embolism. Thrombolytic therapy has been shown to be a successful treatment modality; however, its use somewhat limited due to the risk of hemorrhage and potential for distal embolization in the setting of large mobile thrombi. In patients where either thrombolysis is contraindicated or unsuccessful, and conventional therapies prove inadequate, surgical thrombectomy may be considered. We present a case of percutaneous endovascular extraction of a large mobile mass extending from the inferior vena cava into the right atrium using the Angiovac device, a venovenous bypass system designed for high-volume aspiration of undesired endovascular material. Standard endovascular methods for removal of cancer-associated thrombus, such as catheter-directed lysis, maceration, and exclusion, may prove inadequate in the setting of underlying tumor thrombus. Where conventional endovascular methods either fail or are unsuitable, endovascular thrombectomy with the Angiovac device may be a useful and safe minimally invasive alternative to open resection

  19. Amorphous silicon EPID calibration for dosimetric applications: comparison of a method based on Monte Carlo prediction of response with existing techniques

    International Nuclear Information System (INIS)

    Parent, L; Fielding, A L; Dance, D R; Seco, J; Evans, P M

    2007-01-01

    For EPID dosimetry, the calibration should ensure that all pixels have a similar response to a given irradiation. A calibration method (MC), using an analytical fit of a Monte Carlo simulated flood field EPID image to correct for the flood field image pixel intensity shape, was proposed. It was compared with the standard flood field calibration (FF), with the use of a water slab placed in the beam to flatten the flood field (WS) and with a multiple field calibration where the EPID was irradiated with a fixed 10 x 10 field for 16 different positions (MF). The EPID was used in its normal configuration (clinical setup) and with an additional 3 mm copper slab (modified setup). Beam asymmetry measured with a diode array was taken into account in MC and WS methods. For both setups, the MC method provided pixel sensitivity values within 3% of those obtained with the MF and WS methods (mean difference 2 ) and IMRT fields to within 3% of that obtained with WS and MF calibrations while differences with images calibrated with the FF method for fields larger than 10 x 10 cm 2 were up to 8%. MC, WS and MF methods all provided a major improvement on the FF method. Advantages and drawbacks of each method were reviewed

  20. A New Technique in saving Fingerprint with low volume by using Chaos Game and Fractal Theory

    Directory of Open Access Journals (Sweden)

    Maryam Ashourzadeh

    2010-12-01

    Full Text Available Fingerprint is one of the simplest and most reliable biometric features of human for identification. In this study by using fractal theory and by the assistance of Chaos Game a new fractal is made from fingerprint. While making the new fractal by using Chaos Game mechanism some parameters, which can be used in identification process, can be deciphered. For this purpose, a fractal is made for each fingerprint, we save 10 parameters for every fingerprint, which have necessary information for identity, as said before. So we save 10 decimal parameters with 0.02 accuracy instead of saving the picture of a fingerprint or some parts of it. Now we improve the great volume of fingerprint pictures by using this model which employs fractal for knowing the personality

  1. Calibration of a dedicated software for 3D rendering

    International Nuclear Information System (INIS)

    Abrantes, Marcos E.S.; Felix, Warley F.; Veloso, Maria Auxiliadora F.; Universidade Federal de Minas Gerais

    2017-01-01

    With the increasing use of 3D reconstruction techniques, to assist in diagnosis, dedicated programs are being widely used. For this they must be calibrated in order to encounter the values of the real volumes of the human tissues. The purpose of this work is to indicate correction and calibration values for true volumes, read in a 3D reconstruction system dedicated, using DICOM images of Computed Tomography. This work utilized a PMMA thorax phantom associated with the DICOM image and the volume found by a program of a tomograph. The physical volume of the PMMA phantom found was 10359.0 cm³. For the volumes found according to the structures of interest, the values are 11005.5 cm³, 10249.3 cm³ and 10205.1 cm³ and the correction values are -6.2%, +1.1% e +1.5% respectively for tissues: pulmonary, bony and soft tissues. The procedure performed can be used for calibration in other 3D reconstruction programs, observing the necessary corrections and the methodology used. (author)

  2. Calibration of a dedicated software for 3D rendering

    Energy Technology Data Exchange (ETDEWEB)

    Abrantes, Marcos E.S.; Felix, Warley F.; Veloso, Maria Auxiliadora F., E-mail: marcos.nuclear@yahoo.com.br, E-mail: warleyferreirafelix@gmail.com, E-mail: mdora@nuclear.ufmg.br [Faculdade Ciencias Medicas de Minas Gerais (FCMMG), Belo Horizonte, MG (Brazil); Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-11-01

    With the increasing use of 3D reconstruction techniques, to assist in diagnosis, dedicated programs are being widely used. For this they must be calibrated in order to encounter the values of the real volumes of the human tissues. The purpose of this work is to indicate correction and calibration values for true volumes, read in a 3D reconstruction system dedicated, using DICOM images of Computed Tomography. This work utilized a PMMA thorax phantom associated with the DICOM image and the volume found by a program of a tomograph. The physical volume of the PMMA phantom found was 10359.0 cm³. For the volumes found according to the structures of interest, the values are 11005.5 cm³, 10249.3 cm³ and 10205.1 cm³ and the correction values are -6.2%, +1.1% e +1.5% respectively for tissues: pulmonary, bony and soft tissues. The procedure performed can be used for calibration in other 3D reconstruction programs, observing the necessary corrections and the methodology used. (author)

  3. Dependence of alpha particle track diameter on the free volume holes size using positron annihilation lifetime technique

    Energy Technology Data Exchange (ETDEWEB)

    El-Gamal, S. [Physics Department, Faculty of Education, Ain Shams University, Roxy, 11711 Cairo (Egypt); Abdalla, Ayman M., E-mail: aymanabdalla62@hotmail.com [Physics Department, Faculty of Arts and Sciences, Najran University, Najran (Saudi Arabia); Centre for Advanced Materials and Nano-Engineering, Najran University, Najran 11001 (Saudi Arabia); Abdel-Hady, E.E. [Physics Department, Faculty of Science, Minia University, BO 61519, Minia (Egypt)

    2015-09-15

    The alpha particle track diameter dependence of the free volume holes size (V{sub f}) in DAM–ADC and CR-39 nuclear track detectors was investigated using positron annihilation lifetime technique. The effect of temperature on the alpha particle track diameter and free volume were also investigated in the T-range (RT-130 °C). The obtained results revealed that the values of ortho-positronium lifetime τ{sub 3} and V{sub f} increases while I{sub 3} slightly increases as T increases for the two detectors. The values of τ{sub 3}, V{sub f} and I{sub 3} are higher in CR-39 than DAM–ADC. The interpretation of obtained results is based on the fact that increasing T leads to significant enhancement of thermal expansion of the polymer matrix and consequently V{sub f} increases. The track diameter increases as T increases. This can be explained by the fact that the increase in T increases the crystal size and V{sub f} in the polymer. A relationship between V{sub f} and the alpha particle track diameter was obtained. Moreover results of detector irradiation, along with free volume evaluation are addressed and thoroughly discussed.

  4. Review of current status of high flux heat transfer techniques. Volume I. Text + Appendix A

    International Nuclear Information System (INIS)

    Bauer, W.H.; Gordon, H.S.; Lackner, H.; Mettling, J.R.; Miller, J.E.

    1980-09-01

    The scope of this work comprised two tasks. The first was to review high heat flux technology with consideration given to heat transfer panel configuration, diagnostics techniques and coolant supply. The second task was to prepare a report describing the findings of the review, to recommend the technology offering the least uncertainty for scale-up for the MFTF-B requirement and to recommend any new or perceived requirements for R and D effort

  5. Review of current status of high flux heat transfer techniques. Volume I. Text + Appendix A

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, W.H.; Gordon, H.S.; Lackner, H.; Mettling, J.R.; Miller, J.E.

    1980-09-01

    The scope of this work comprised two tasks. The first was to review high heat flux technology with consideration given to heat transfer panel configuration, diagnostics techniques and coolant supply. The second task was to prepare a report describing the findings of the review, to recommend the technology offering the least uncertainty for scale-up for the MFTF-B requirement and to recommend any new or perceived requirements for R and D effort.

  6. Probabilistic risk assessment course documentation. Volume 5. System reliability and analysis techniques Session D - quantification

    International Nuclear Information System (INIS)

    Lofgren, E.V.

    1985-08-01

    This course in System Reliability and Analysis Techniques focuses on the probabilistic quantification of accident sequences and the link between accident sequences and consequences. Other sessions in this series focus on the quantification of system reliability and the development of event trees and fault trees. This course takes the viewpoint that event tree sequences or combinations of system failures and success are available and that Boolean equations for system fault trees have been developed and are available. 93 figs., 11 tabs

  7. Proceedings of the seventeenth annual conference on explosives and blasting technique. Volume 1

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Papers from this conference dealt with the following topics: surface and underground mine blasting, control of blast effects in sensitive areas, blasthole deviation, regulatory impact when blasting at Superfund sites, computer-aided blast design and monitoring, tunneling techniques, shaft excavations, video camera analysis of blasting operations, soil densification, cost optimization, mine blasting accidents, non-electric initiation systems, and delay detonators. Papers have been indexed separately for inclusion on the data base

  8. SU-F-T-254: Dose Volume Histogram (DVH) Analysis of Breath Hold Vs Free Breathing Techniques for Esophageal Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Badkul, R; Doke, K; Pokhrel, D; Aguilera, N; Lominska, C [University of Kansas Medical Center, Kansas City, KS (United States)

    2016-06-15

    Purpose: Lung and heart doses and associated toxicity are of concern in radiotherapy for esophageal cancer. This study evaluates the dosimetry of deep-inspiration-breath-hold (DIBH) technique as compared to freebreathing( FB) using 3D-conformal treatment(3D-CRT) of esophageal cancer. Methods: Eight patients were planned with FB and DIBH CT scans. DIBH scans were acquired using Varian RPM system. FB and DIBH CTs were contoured per RTOG-1010 to create the planning target volume(PTV) as well as organs at risk volumes(OAR). Two sets of gross target volumes(GTV) with 5cm length were contoured for each patient: proximal at the level of the carina and distal at the level of gastroesophageal junction and were enlarged with appropriate margin to generate Clinical Target Volume and PTV. 3D-CRT plans were created on Eclipse planning system for 45Gy to cover 95% of PTV in 25 fractions for both proximal and distal tumors on FB and DIBH scans. For distal tumors celiac nodes were covered electively. DVH parameters for lung and heart OARs were generated and analyzed. Results: All DIBH DVH parameters were normalized to FB plan values. Average of heart-mean and heart-V40 was 0.70 and 0.66 for proximal lesions. For distal lesions ratios were 1.21 and 2.22 respectively. For DIBH total lung volume increased by 2.43 times versus FB scan. Average of lung-mean, V30, V20, V10, V5 are 0.82, 0.92, 0.76, 0.77 and 0.79 for proximal lesions and 1.17,0.66,0.87,0.93 and 1.03 for distal lesions. Heart doses were lower for breath-hold proximal lesions but higher for distal lesions as compared to free-breathing plans. Lung doses were lower for both proximal and distal breath-hold lesions except mean lung dose and V5 for distal lesions. Conclusion: This study showed improvement of OAR doses for esophageal lesions at mid-thoracic level utilizing DIBH vs FB technique but did not show consistent OAR sparing with DIBH for distal lesions.

  9. SU-F-T-254: Dose Volume Histogram (DVH) Analysis of Breath Hold Vs Free Breathing Techniques for Esophageal Tumors

    International Nuclear Information System (INIS)

    Badkul, R; Doke, K; Pokhrel, D; Aguilera, N; Lominska, C

    2016-01-01

    Purpose: Lung and heart doses and associated toxicity are of concern in radiotherapy for esophageal cancer. This study evaluates the dosimetry of deep-inspiration-breath-hold (DIBH) technique as compared to freebreathing( FB) using 3D-conformal treatment(3D-CRT) of esophageal cancer. Methods: Eight patients were planned with FB and DIBH CT scans. DIBH scans were acquired using Varian RPM system. FB and DIBH CTs were contoured per RTOG-1010 to create the planning target volume(PTV) as well as organs at risk volumes(OAR). Two sets of gross target volumes(GTV) with 5cm length were contoured for each patient: proximal at the level of the carina and distal at the level of gastroesophageal junction and were enlarged with appropriate margin to generate Clinical Target Volume and PTV. 3D-CRT plans were created on Eclipse planning system for 45Gy to cover 95% of PTV in 25 fractions for both proximal and distal tumors on FB and DIBH scans. For distal tumors celiac nodes were covered electively. DVH parameters for lung and heart OARs were generated and analyzed. Results: All DIBH DVH parameters were normalized to FB plan values. Average of heart-mean and heart-V40 was 0.70 and 0.66 for proximal lesions. For distal lesions ratios were 1.21 and 2.22 respectively. For DIBH total lung volume increased by 2.43 times versus FB scan. Average of lung-mean, V30, V20, V10, V5 are 0.82, 0.92, 0.76, 0.77 and 0.79 for proximal lesions and 1.17,0.66,0.87,0.93 and 1.03 for distal lesions. Heart doses were lower for breath-hold proximal lesions but higher for distal lesions as compared to free-breathing plans. Lung doses were lower for both proximal and distal breath-hold lesions except mean lung dose and V5 for distal lesions. Conclusion: This study showed improvement of OAR doses for esophageal lesions at mid-thoracic level utilizing DIBH vs FB technique but did not show consistent OAR sparing with DIBH for distal lesions.

  10. Low level waste management: a compilation of models and monitoring techniques. Volume 1

    International Nuclear Information System (INIS)

    Mosier, J.E.; Fowler, J.R.; Barton, C.J.

    1980-04-01

    In support of the National Low-Level Waste (LLW) Management Research and Development Program being carried out at Oak Ridge National Laboratory, Science Applications, Inc., conducted a survey of models and monitoring techniques associated with the transport of radionuclides and other chemical species from LLW burial sites. As a result of this survey, approximately 350 models were identified. For each model the purpose and a brief description are presented. To the extent possible, a point of contact and reference material are identified. The models are organized into six technical categories: atmospheric transport, dosimetry, food chain, groundwater transport, soil transport, and surface water transport. About 4% of the models identified covered other aspects of LLW management and are placed in a miscellaneous category. A preliminary assessment of all these models was performed to determine their ability to analyze the transport of other chemical species. The models that appeared to be applicable are identified. A brief survey of the state-of-the-art techniques employed to monitor LLW burial sites is also presented, along with a very brief discussion of up-to-date burial techniques

  11. Low level waste management: a compilation of models and monitoring techniques. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Mosier, J.E.; Fowler, J.R.; Barton, C.J. (comps.)

    1980-04-01

    In support of the National Low-Level Waste (LLW) Management Research and Development Program being carried out at Oak Ridge National Laboratory, Science Applications, Inc., conducted a survey of models and monitoring techniques associated with the transport of radionuclides and other chemical species from LLW burial sites. As a result of this survey, approximately 350 models were identified. For each model the purpose and a brief description are presented. To the extent possible, a point of contact and reference material are identified. The models are organized into six technical categories: atmospheric transport, dosimetry, food chain, groundwater transport, soil transport, and surface water transport. About 4% of the models identified covered other aspects of LLW management and are placed in a miscellaneous category. A preliminary assessment of all these models was performed to determine their ability to analyze the transport of other chemical species. The models that appeared to be applicable are identified. A brief survey of the state-of-the-art techniques employed to monitor LLW burial sites is also presented, along with a very brief discussion of up-to-date burial techniques.

  12. Amorphous silicon EPID calibration for dosimetric applications: comparison of a method based on Monte Carlo prediction of response with existing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Parent, L [Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton (United Kingdom); Fielding, A L [School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane (Australia); Dance, D R [Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London (United Kingdom); Seco, J [Department of Radiation Oncology, Francis Burr Proton Therapy Center, Massachusetts General Hospital, Harvard Medical School, Boston (United States); Evans, P M [Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton (United Kingdom)

    2007-07-21

    For EPID dosimetry, the calibration should ensure that all pixels have a similar response to a given irradiation. A calibration method (MC), using an analytical fit of a Monte Carlo simulated flood field EPID image to correct for the flood field image pixel intensity shape, was proposed. It was compared with the standard flood field calibration (FF), with the use of a water slab placed in the beam to flatten the flood field (WS) and with a multiple field calibration where the EPID was irradiated with a fixed 10 x 10 field for 16 different positions (MF). The EPID was used in its normal configuration (clinical setup) and with an additional 3 mm copper slab (modified setup). Beam asymmetry measured with a diode array was taken into account in MC and WS methods. For both setups, the MC method provided pixel sensitivity values within 3% of those obtained with the MF and WS methods (mean difference <1%, standard deviation <2%). The difference of pixel sensitivity between MC and FF methods was up to 12.2% (clinical setup) and 11.8% (modified setup). MC calibration provided images of open fields (5 x 5 to 20 x 20 cm{sup 2}) and IMRT fields to within 3% of that obtained with WS and MF calibrations while differences with images calibrated with the FF method for fields larger than 10 x 10 cm{sup 2} were up to 8%. MC, WS and MF methods all provided a major improvement on the FF method. Advantages and drawbacks of each method were reviewed.

  13. Tree Climbing Techniques and Volume Equations for Eschweilera (Matá-Matá, a Hyperdominant Genus in the Amazon Forest

    Directory of Open Access Journals (Sweden)

    Bruno O. Gimenez

    2017-05-01

    Full Text Available The Eschweilera genus has great ecological and economic importance due to its wide abundance in the Amazon basin. One potential use for the Eschweilera genus is in forest management, where just a few trees are removed per hectare. In order to improve the forest management in the Amazon, this study assessed two critical issues: volume equations fitted for a single genus and the development of a non-destructive method using climbing techniques. The equipment used to measure the sample trees included: climbing rope, ascenders, descenders, and carabiners. To carry out the objectives of this study, 64 trees with diameter at breast height (DBH ≥ 10 cm were selected and measured in ZF-2 Tropical Forestry Station near the city of Manaus, Brazil. Four single input models with DBH and four dual input models with DBH and merchantable height (H were tested. The Husch model (V = a × DBHb presented the best performance (R2 = 0.97. This model does not require the merchantable height, which is an important advantage, because of the difficulty in measuring this variable in tropical forests. When the merchantable height data are collected using accurate methods, the Schumacher and Hall model (V = a × DBHb × Hc is the most appropriated. Tree climbing techniques with the use of ropes, as a non-destructive method, is a good alternative to measure the merchantable height, the diameter along the stem, and also estimate the tree volume (m3 of the Eschweilera genus in the Amazon basin.

  14. Campaign for vicarious calibration of SumbandilaSat in Argentina

    CSIR Research Space (South Africa)

    Vhengani, LM

    2011-07-01

    Full Text Available assessment, they are also calibrated post-launch. Various post-launch techniques exist including cross-sensor, solar, lunar and vicarious calibration. Vicarious calibration relies on in-situ measurements of surface reflectance and atmospheric transmittance...

  15. Instrumentation calibration

    International Nuclear Information System (INIS)

    Mack, D.A.

    1976-08-01

    Procedures for the calibration of different types of laboratory equipment are described. Provisions for maintaining the integrity of reference and working standards traceable back to a national standard are discussed. Methods of validation and certification methods are included. An appendix lists available publications and services of national standardizing agencies

  16. Probabilistic risk assessment course documentation. Volume 3. System reliability and analysis techniques, Session A - reliability

    International Nuclear Information System (INIS)

    Lofgren, E.V.

    1985-08-01

    This course in System Reliability and Analysis Techniques focuses on the quantitative estimation of reliability at the systems level. Various methods are reviewed, but the structure provided by the fault tree method is used as the basis for system reliability estimates. The principles of fault tree analysis are briefly reviewed. Contributors to system unreliability and unavailability are reviewed, models are given for quantitative evaluation, and the requirements for both generic and plant-specific data are discussed. Also covered are issues of quantifying component faults that relate to the systems context in which the components are embedded. All reliability terms are carefully defined. 44 figs., 22 tabs

  17. Improved Optical Document Security Techniques Based on Volume Holography and Lippmann Photography

    Science.gov (United States)

    Bjelkhagen, Hans I.

    Optical variable devices (OVDs), such as holograms, are now common in the field of document security. Up until now mass-produced embossed holograms or other types of mass-produced OVDs are used not only for banknotes but also for personalized documents, such as passports, ID cards, travel documents, driving licenses, credit cards, etc. This means that identical OVDs are used on documents issued to individuals. Today, there is need for a higher degree of security on such documents and this chapter covers new techniques to make improved mass-produced or personalized OVDs.

  18. Fracture detection in crystalline rock using ultrasonic reflection techniques: Volume 1

    International Nuclear Information System (INIS)

    Palmer, S.P.

    1982-11-01

    This research was initiated to investigate using ultrasonic seismic reflection techniques to detect fracture discontinuities in a granitic rock. Initial compressional (P) and shear (SH) wave experiments were performed on a 0.9 x 0.9 x 0.3 meter granite slab in an attempt to detect seismic energy reflected from the opposite face of the slab. It was found that processing techniques such as deconvolution and array synthesis could improve the standout of the reflection event. During the summers of 1979 and 1980 SH reflection experiments were performed at a granite quarry near Knowles, California. The purpose of this study was to use SH reflection methods to detect an in situ fracture located one to three meters behind the quarry face. These SH data were later analyzed using methods similar to those applied in the laboratory. Interpretation of the later-arriving events observed in the SH field data as reflections from a steeply-dipping fracture was inconclusive. 41 refs., 43 figs., 7 tabs

  19. Gamma counter calibration system

    International Nuclear Information System (INIS)

    1977-01-01

    A method and apparatus are described for the calibration of a gamma radiation measurement instrument to be used over any of a number of different absolute energy ranges. The method includes the steps of adjusting the overall signal gain associated with pulses which are derived from detected gamma rays, until the instrument is calibrated for a particular absolute energy range; then storing parameter settings corresponding to the adjusted overall signal gain, and repeating the process for other desired absolute energy ranges. The stored settings can be subsequently retrieved and reapplied so that test measurements can be made using a selected one of the absolute energy ranges. Means are provided for adjusting the overall signal gain and a specific technique is disclosed for making coarse, then fine adjustments to the signal gain, for rapid convergence of the required calibration settings. (C.F.)

  20. The effects of low-volume resistance training with and without advanced techniques in trained subjects.

    Science.gov (United States)

    Gieβsing, Jùrgen; Fisher, James; Steele, James; Rothe, Frank; Raubold, Kristin; Eichmann, Björn

    2016-03-01

    This study examined low-volume resistance training (RT) in trained participants with and without advanced training methods. Trained participants (RT experience 4±3 years) were randomised to groups performing single-set RT: ssRM (N.=21) performing repetitions to self-determined repetition maximum (RM), ssMMF (N.=30) performing repetitions to momentary muscular failure (MMF), and ssRP (N.=28) performing repetitions to self-determined RM using a rest pause (RP) method. Each performed supervised RT twice/week for 10 weeks. Outcomes included maximal isometric strength and body composition using bioelectrical impedance analysis. The ssRM group did not significantly improve in any outcome. The ssMMF and ssRP groups both significantly improved strength (p < 0.05). Magnitude of changes using effect size (ES) was examined between groups. Strength ES's were considered large for ssMMF (0.91 to 1.57) and ranging small to large for ssRP (0.42 to 1.06). Body composition data revealed significant improvements (P<0.05) in muscle and fat mass and percentages for whole body, upper limbs and trunk for ssMMF, but only upper limbs for ssRP. Body composition ES's ranged moderate to large for ssMMF (0.56 to 1.27) and ranged small to moderate for ssRP (0.28 to 0.52). ssMMF also significantly improved (P<0.05) total abdominal fat and increased intracellular water with moderate ES's (-0.62 and 0.56, respectively). Training to self-determined RM is not efficacious for trained participants. Training to MMF produces greatest improvements in strength and body composition, however, RP style training does offer some benefit.

  1. Comparison of different methods for liquid level adjustment in tank prover calibration

    International Nuclear Information System (INIS)

    Garcia, D A; Farias, E C; Gabriel, P C; Aquino, M H; Gomes, R S E; Aibe, V Y

    2015-01-01

    The adjustment of the liquid level during the calibration of tank provers with fixed volume is normally done by overfill but it can be done in different ways. In this article four level adjustment techniques are compared: plate, pipette, ruler and overfill adjustment. The adjustment methods using plate and pipette presented good agreement with the tank's nominal volume and lower uncertainty among the tested methods

  2. Advancement in solar evaporation techniques for volume reduction of chemical effluents

    Energy Technology Data Exchange (ETDEWEB)

    Parakasamurthy, K S [Nuclear Fuel Complex, Hyderabad (India); Pande, D P [Process Engineering and Systems Development Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    A typical example of advancement of a unit operation for the given requirement is described. The solar evaporation ponds (SEP) have technical and economic advantages compared to other evaporation methods for concentrating chemical effluents. The operation of SEP is strongly dependent on the environmental and site conditions. Tropical conditions with high solar incidence, good wind speed along with hot and dry weather provide suitable climate for efficient operation of solar evaporation ponds. The particular site selected for the ponds at Nuclear Fuel Complex (NFC) has a rocky terrain with murrum over sheet with very low water table and small velocity of groundwater. During the past twenty five years extensive theoretical and experimental investigations have been carried out for advancement of solar evaporation technique. (author). 7 refs.

  3. Advancement in solar evaporation techniques for volume reduction of chemical effluents

    International Nuclear Information System (INIS)

    Parakasamurthy, K.S.; Pande, D.P.

    1994-01-01

    A typical example of advancement of a unit operation for the given requirement is described. The solar evaporation ponds (SEP) have technical and economic advantages compared to other evaporation methods for concentrating chemical effluents. The operation of SEP is strongly dependent on the environmental and site conditions. Tropical conditions with high solar incidence, good wind speed along with hot and dry weather provide suitable climate for efficient operation of solar evaporation ponds. The particular site selected for the ponds at Nuclear Fuel Complex (NFC) has a rocky terrain with murrum over sheet with very low water table and small velocity of groundwater. During the past twenty five years extensive theoretical and experimental investigations have been carried out for advancement of solar evaporation technique. (author)

  4. Calibration and simulation of Heston model

    Directory of Open Access Journals (Sweden)

    Mrázek Milan

    2017-05-01

    Full Text Available We calibrate Heston stochastic volatility model to real market data using several optimization techniques. We compare both global and local optimizers for different weights showing remarkable differences even for data (DAX options from two consecutive days. We provide a novel calibration procedure that incorporates the usage of approximation formula and outperforms significantly other existing calibration methods.

  5. Robust volume assessment of brain tissues for 3-dimensional fourier transformation MRI via a novel multispectral technique.

    Directory of Open Access Journals (Sweden)

    Jyh-Wen Chai

    Full Text Available A new TRIO algorithm method integrating three different algorithms is proposed to perform brain MRI segmentation in the native coordinate space, with no need of transformation to a standard coordinate space or the probability maps for segmentation. The method is a simple voxel-based algorithm, derived from multispectral remote sensing techniques, and only requires minimal operator input to depict GM, WM, and CSF tissue clusters to complete classification of a 3D high-resolution multislice-multispectral MRI data. Results showed very high accuracy and reproducibility in classification of GM, WM, and CSF in multislice-multispectral synthetic MRI data. The similarity indexes, expressing overlap between classification results and the ground truth, were 0.951, 0.962, and 0.956 for GM, WM, and CSF classifications in the image data with 3% noise level and 0% non-uniformity intensity. The method particularly allows for classification of CSF with 0.994, 0.961 and 0.996 of accuracy, sensitivity and specificity in images data with 3% noise level and 0% non-uniformity intensity, which had seldom performed well in previous studies. As for clinical MRI data, the quantitative data of brain tissue volumes aligned closely with the brain morphometrics in three different study groups of young adults, elderly volunteers, and dementia patients. The results also showed very low rates of the intra- and extra-operator variability in measurements of the absolute volumes and volume fractions of cerebral GM, WM, and CSF in three different study groups. The mean coefficients of variation of GM, WM, and CSF volume measurements were in the range of 0.03% to 0.30% of intra-operator measurements and 0.06% to 0.45% of inter-operator measurements. In conclusion, the TRIO algorithm exhibits a remarkable ability in robust classification of multislice-multispectral brain MR images, which would be potentially applicable for clinical brain volumetric analysis and explicitly promising

  6. The effect of patient position and field configuration on lung volume in the treatment of advanced carcinoma of the breast or lung volumes in breast techniques - a case study

    International Nuclear Information System (INIS)

    Floyd, J.L.

    1989-01-01

    The position of the patient together with the configuration of the treatment fields play an important role in the volume of lung irradiated in breast techniques. These factors are even more important when the staging of the disease is advanced. A comparison of lung volumes is made with the patient in three treatment positions, and the effect of beam angling is demonstrated. A method of calculating the approximated lung volume from port films is proposed, together with a comparative analysis of the data obtained. Clinical decisions affecting technical considerations are examined. 6 refs., 5 figs

  7. Quality of the neutron probe calibration curve

    International Nuclear Information System (INIS)

    Libardi, Paulo Leonel; Moraes, Sergio Oliveira

    1997-01-01

    An experiment of neutron probe calibration has been performed, involving various volume size samples and collected at various distances from the access tubes. The experiment aimed to give some answers to questions such as suitable sample physical volume, always use of the same volume and sample distance from the neutron probe access tube

  8. 125I-induced DNA double strand breaks: use in calibration of the neutral filter elution technique and comparison with X-ray induced breaks

    International Nuclear Information System (INIS)

    Radford, I.R.; Hodgson, G.S.

    1985-01-01

    The neutral filter elution assay, for measurement of DNA double strand breakage, has been calibrated using mouse L cells and Chinese hamster V79 cells labelled with [ 125 I]dUrd and then held at liquid nitrogen temperature to accumulate decays. The basis of the calibration is the observation that each 125 I decay, occurring in DNA, produces a DNA double strand break. Linear relationships between 125 I decays per cell and lethal lesions per cell (minus natural logarithm survival) and the level of elution, were found. Using the calibration data, it was calculated that the yield of DNA double strand breaks after X-irradiation of both cell types was from 6 to 9 x 10 -12 DNA double strand breaks per Gy per dalton of DNA, for doses greater than 6 Gy. Neutral filter elution and survival data for X-irradiated and 125 I-labelled cells suggested that the relationships between lethal lesions and DNA double strand breakage were significantly different for both cell types. An attempt was made to study the repair kinetics for 125 I-induced DNA double strand breaks, but was frustrated by the rapid DNA degradation which occurs in cells that have been killed by the freezing-thawing process. (author)

  9. Calibration-free technique for the measurement of oxygen saturation changes in muscles of marine mammals and its proof of concept

    Science.gov (United States)

    Ortega-Martinez, Antonio; Goenka, Chhavi; Booker, Marloes; Grange, Robert M. H.; Hindle, Allyson G.; Franco, Walfre

    2018-02-01

    Marine mammals possess impressive breath-holding capabilities made possible by physiological adjustments during dives. Studying marine mammals in their natural environment unravels vital information about these physiological adjustments particularly when we can monitor altered dive behavior in response to stressful situations such as human-induced oceanic disturbances, presence of predators and altered prey distributions. An important indicator of physiological status during submergence is the change in oxygen saturation in the muscles and blood of these mammals. In this work, we aim to investigate oxygen storage and consumption in the muscles of free-diving elephant seals when exposed to disturbances such as sonar or predator sounds while they are at sea. Optical oxygen sensors are a mature technology with multiple medical applications that provide a way to measure oxygenation changes in biological tissues in a minimally invasive manner. While these sensors are well calibrated and readily available for humans, they are still inadequate for marine mammals primarily due to a very small number of test candidates and therefore little data is available for validation and calibration. We propose a probe geometry and associated mathematical model for measuring muscle oxygenation in seals based on near infrared diffuse transport with no need for calibration. A prototype based on this concept has been designed and tested on humans and rats. We use the test results to discuss the advantages and limitations of the approach. We also detail the constraints on size, sensor location, electronics, light source properties and detector characteristics posed by the unique biology of seals.

  10. Mid-Face Volumization With Hyaluronic Acid: Injection Technique and Safety Aspects from a Controlled, Randomized, Double-Blind Clinical Study.

    Science.gov (United States)

    Prager, Welf; Agsten, Karla; Kravtsov, Maria; Kerscher, Prof Martina

    2017-04-01

    BACKGROUND: Injection of hyaluronic acid (HA) volumizing fillers in the malar area is intended for rejuvenation of the mid-face. The choice of products, depth, and technique of injection depends on the desired level of volume enhancement and practitioners' preferences. OBJECTIVE: To describe a volumizing injection technique in the scope of a controlled, randomized, double-blind, single-center, split-face clinical study. A total of 45 subjects with bilateral symmetrical moderate to severe volume loss in the malar area received a single 2 mL injection of CPM®-26 (Cohesive Polydensified Matrix®) on one side and VYC®-20 (VYCROSS®) on the contralateral side of the face. The same injection technique was applied for both sides of the face. Use of anesthetics, overcorrection, and touch-ups were not permitted. The investigator completed a product satisfaction questionnaire. Adverse events (AE) and injection-site reactions (ISRs) were reported during the study. RESULTS: The products were placed at the epiperiosteal depth in 88.9% (n=40), at the subdermal depth in 8.9% (n=4) and at both levels in 2.2% (n=1) of subjects. Fanning technique using cannulae was applied in most cases (97.8%, n=44). Results of the investigator satisfaction questionnaire allowed to characterize CPM-26 in comparison to other volumizing gels. Both study products were generally well tolerated. Local reactions were transient and of mild to moderate intensity, with the most frequent ones being redness, pain, and swelling. CONCLUSION: Adequate injection technique in volumizing treatments is essential to create a natural aesthetic rejuvenation while respecting the safety aspect of the procedures. A 22G blunt cannula used with CPM-26 was preferred due to an easier and a more homogeneous distribution of the product. The investigator also appreciated CPM-26 for its ease of injection, positioning, lifting, and volumizing capacity. J Drugs Dermatol. 2017;16(4):351-357..

  11. LANL MTI calibration team experience

    Science.gov (United States)

    Bender, Steven C.; Atkins, William H.; Clodius, William B.; Little, Cynthia K.; Christensen, R. Wynn

    2004-01-01

    The Multispectral Thermal Imager (MTI) was designed as an imaging radiometer with absolute calibration requirements established by Department of Energy (DOE) mission goals. Particular emphasis was given to water surface temperature retrieval using two mid wave and three long wave infrared spectral bands, the fundamental requirement was a surface temperature determination of 1K at the 68% confidence level. For the ten solar reflective bands a one-sigma radiometric performance goal of 3% was established. In order to address these technical challenges a calibration facility was constructed containing newly designed sources that were calibrated at NIST. Additionally, the design of the payload and its onboard calibration system supported post launch maintenance and update of the ground calibration. The on-orbit calibration philosophy also included vicarious techniques using ocean buoys, playas and other instrumented sites; these became increasingly important subsequent to an electrical failure which disabled the onboard calibration system. This paper offers various relevant lessons learned in the eight-year process of reducing to practice the calibration capability required by the scientific mission. The discussion presented will include observations pertinent to operational and procedural issues as well as hardware experiences; the validity of some of the initial assumptions will also be explored.

  12. A force measurement system based on an electrostatic sensing and actuating technique for calibrating force in a micronewton range with a resolution of nanonewton scale

    International Nuclear Information System (INIS)

    Chen, Sheng-Jui; Pan, Sheau-Shi

    2011-01-01

    This paper introduces a force measurement system recently established at the Center for Measurement Standards, Industrial Technology Research Institute for calibrating forces in a micronewton range with a resolution of a few nanonewtons. The force balance consists of a monolithic flexure stage and a specially made capacitor for electrostatic sensing and actuating. The capacitor is formed by three electrodes which can be utilized as a capacitive position sensor and an electrostatic force actuator at the same time. Force balance control is implemented with a digital controller by which the signal of the stage deflection is acquired, filtered and fed back to the electrostatic force driver to bring the flexure stage to the null position. The detailed description of the apparatus including the design of a monolithic flexure stage, principle of capacitive position sensing/electrostatic actuation and the force balance control is given in the paper. Finally, we present the results of electrostatic force calibration and the weighing of a 1 mg wire weight

  13. On combination of strict Bayesian principles with model reduction technique or how stochastic model calibration can become feasible for large-scale applications

    Science.gov (United States)

    Oladyshkin, S.; Schroeder, P.; Class, H.; Nowak, W.

    2013-12-01

    Predicting underground carbon dioxide (CO2) storage represents a challenging problem in a complex dynamic system. Due to lacking information about reservoir parameters, quantification of uncertainties may become the dominant question in risk assessment. Calibration on past observed data from pilot-scale test injection can improve the predictive power of the involved geological, flow, and transport models. The current work performs history matching to pressure time series from a pilot storage site operated in Europe, maintained during an injection period. Simulation of compressible two-phase flow and transport (CO2/brine) in the considered site is computationally very demanding, requiring about 12 days of CPU time for an individual model run. For that reason, brute-force approaches for calibration are not feasible. In the current work, we explore an advanced framework for history matching based on the arbitrary polynomial chaos expansion (aPC) and strict Bayesian principles. The aPC [1] offers a drastic but accurate stochastic model reduction. Unlike many previous chaos expansions, it can handle arbitrary probability distribution shapes of uncertain parameters, and can therefore handle directly the statistical information appearing during the matching procedure. We capture the dependence of model output on these multipliers with the expansion-based reduced model. In our study we keep the spatial heterogeneity suggested by geophysical methods, but consider uncertainty in the magnitude of permeability trough zone-wise permeability multipliers. Next combined the aPC with Bootstrap filtering (a brute-force but fully accurate Bayesian updating mechanism) in order to perform the matching. In comparison to (Ensemble) Kalman Filters, our method accounts for higher-order statistical moments and for the non-linearity of both the forward model and the inversion, and thus allows a rigorous quantification of calibrated model uncertainty. The usually high computational costs of

  14. Hole-expansion formability of dual-phase steels using representative volume element approach with boundary-smoothing technique

    International Nuclear Information System (INIS)

    Kim, Ji Hoon; Lee, M.G.; Kim, D.; Matlock, D.K.; Wagoner, R.H.

    2010-01-01

    Research highlights: → Robust microstructure-based FE mesh generation technique was developed. → Local deformation behavior near phase boundaries could be quantitatively understood. → Macroscopic failure could be connected to microscopic deformation behavior of multi-phase steel. - Abstract: A qualitative analysis was carried out on the formability of dual-phase (DP) steels by introducing a realistic microstructure-based finite element approach. The present microstructure-based model was constructed using a mesh generation process with a boundary-smoothing algorithm after proper image processing. The developed model was applied to hole-expansion formability tests for DP steel sheets having different volume fractions and morphological features. On the basis of the microstructural inhomogeneity observed in the scanning electron micrographs of the DP steel sheets, it was inferred that the localized plastic deformation in the ferritic phase might be closely related to the macroscopic formability of DP steel. The experimentally observed difference between the hole-expansion formability of two different microstructures was reasonably explained by using the present finite element model.

  15. Assessing high altitude glacier thickness, volume and area changes using field, GIS and remote sensing techniques: the case of Nevado Coropuna (Peru

    Directory of Open Access Journals (Sweden)

    P. Peduzzi

    2010-08-01

    Full Text Available Higher temperatures and changes in precipitation patterns have induced an acute decrease in Andean glaciers, thus leading to additional stress on water supply. To adapt to climate changes, local governments need information on the rate of glacier area and volume losses and on current ice thickness. Remote sensing analyses of Coropuna glacier (Peru delineate an acute glaciated area decline between 1955 and 2008. We tested how volume changes can be estimated with remote sensing and GIS techniques using digital elevation models derived from both topographic maps and satellite images. Ice thickness was measured in 2004 using a Ground Penetrating Radar coupled with a Ground Positioning System during a field expedition. It provided profiles of ice thickness on different slopes, orientations and altitudes. These were used to model the current glacier volume using Geographical Information System and statistical multiple regression techniques. The results revealed a significant glacier volume loss; however the uncertainty is higher than the measured volume loss. We also provided an estimate of the remaining volume. The field study provided the scientific evidence needed by COPASA, a local Peruvian NGO, and GTZ, the German international cooperation agency, in order to alert local governments and communities and guide them in adopting new climate change adaptation policies.

  16. Calibration of the SNO+ experiment

    Science.gov (United States)

    Maneira, J.; Falk, E.; Leming, E.; Peeters, S.; SNO+ Collaboration.

    2017-09-01

    The main goal of the SNO+ experiment is to perform a low-background and high-isotope-mass search for neutrinoless double-beta decay, employing 780 tonnes of liquid scintillator loaded with tellurium, in its initial phase at 0.5% by mass for a total mass of 1330 kg of 130Te. The SNO+ physics program includes also measurements of geo- and reactor neutrinos, supernova and solar neutrinos. Calibrations are an essential component of the SNO+ data-taking and analysis plan. The achievement of the physics goals requires both an extensive and regular calibration. This serves several goals: the measurement of several detector parameters, the validation of the simulation model and the constraint of systematic uncertainties on the reconstruction and particle identification algorithms. SNO+ faces stringent radiopurity requirements which, in turn, largely determine the materials selection, sealing and overall design of both the sources and deployment systems. In fact, to avoid frequent access to the inner volume of the detector, several permanent optical calibration systems have been developed and installed outside that volume. At the same time, the calibration source internal deployment system was re-designed as a fully sealed system, with more stringent material selection, but following the same working principle as the system used in SNO. This poster described the overall SNO+ calibration strategy, discussed the several new and innovative sources, both optical and radioactive, and covered the developments on source deployment systems.

  17. A new adsorption-elution technique for the concentration of aquatic extracellular antibiotic resistance genes from large volumes of water.

    Science.gov (United States)

    Wang, Da-Ning; Liu, Lu; Qiu, Zhi-Gang; Shen, Zhi-Qiang; Guo, Xuan; Yang, Dong; Li, Jing; Liu, Wei-Li; Jin, Min; Li, Jun-Wen

    2016-04-01

    Extracellular antibiotic resistance genes (eARGs) that help in the transmission and spread of antibiotic-resistant bacteria are emerging environmental contaminants in water, and there is therefore a growing need to assess environmental levels and associated risks of eARGs. However, as they are present in low amounts, it is difficult to detect eARGs in water directly with PCR techniques. Here, we prepared a new type of nucleic acid adsorption particle (NAAP) with high capacity and developed an optimal adsorption-elution method to concentrate eARGs from large volumes of water. With this technique, we were able to achieve an eARG recovery rate of above 95% from 10 L of water samples. Moreover, combining this new method with quantitative real-time PCR (qPCR), the sensitivity of the eARG detection was 10(4) times that of single qPCR, with the detection limit lowered to 100 gene copies (GCs)/L. Our analyses showed that the eARG load, virus load and certain water characteristics such as pH, chemical oxygen demand (CODMn), and turbidity affected the eARGs recovery rate. However, high eARGs recovery rates always remained within the standard limits for natural surface water quality, while eARG levels in water were lower than the detection limits of single qPCR assays. The recovery rates were not affected by water temperature and heterotrophic plate counts (HPC). The eARGs whatever located in the plasmids or the short-length linear DNAs can be recovered from the water. Furthermore, the recovery rate was high even in the presence of high concentrations of plasmids in different natural water (Haihe river, well water, raw water for drinking water, Jinhe river, Tuanbo lake and the Yunqiao reservoir). By this technology, eARGs concentrations were found ranging from (2.70 ± 0.73) × 10(2) to (4.58 ± 0.47) × 10(4) GCs/L for the extracellular ampicillin resistance gene and (5.43 ± 0.41) × 10(2) to (2.14 ± 0.23) × 10(4) GCs/L for the extracellular gentamicin

  18. Feasibility of volume-of-interest (VOI) scanning technique in cone beam breast CT - a preliminary study

    International Nuclear Information System (INIS)

    Chen Lingyun; Shaw, Chris C.; Altunbas, Mustafa C.; Lai, C.-J.; Liu Xinming; Han Tao; Wang Tianpeng; Yang, Wei T.; Whitman, Gary J.

    2008-01-01

    This work is to demonstrate that high quality cone beam CT images can be generated for a volume of interest (VOI) and to investigate the exposure reduction effect, dose saving, and scatter reduction with the VOI scanning technique. The VOI scanning technique involves inserting a filtering mask between the x-ray source and the breast during image acquisition. The mask has an opening to allow full x-ray exposure to be delivered to a preselected VOI and a lower, filtered exposure to the region outside the VOI. To investigate the effects of increased noise due to reduced exposure outside the VOI on the reconstructed VOI image, we directly extracted the projection data inside the VOI from the full-field projection data and added additional data to the projection outside the VOI to simulate the relative noise increase due to reduced exposure. The nonuniform reference images were simulated in an identical manner to normalize the projection images and measure the x-ray attenuation factor for the object. Regular Feldkamp-Davis-Kress filtered backprojection algorithm was used to reconstruct the 3D images. The noise level inside the VOI was evaluated and compared with that of the full-field higher exposure image. Calcifications phantom and low contrast phantom were imaged. Dose reduction was investigated by estimating the dose distribution in a cylindrical water phantom using Monte Carlo simulation based Geant4 package. Scatter reduction at the detector input was also studied. Our results show that with the exposure level reduced by the VOI mask, the dose levels were significantly reduced both inside and outside the VOI without compromising the accuracy of image reconstruction, allowing for the VOI to be imaged with more clarity and helping to reduce the breast dose. The contrast-to-noise ratio inside the VOI was improved. The VOI images were not adversely affected by noisier projection data outside the VOI. Scatter intensities at the detector input were also shown to

  19. Recommended inorganic chemicals for calibration

    International Nuclear Information System (INIS)

    Moody, J.R.; Greenberg, R.R.; Pratt, K.W.; Rains, T.C.

    1988-01-01

    All analytical techniques depend on the use of calibration chemicals to relate analyte concentration to an instrumental parameter. A fundamental component in the preparation of calibration solutions is the weighing of a pure chemical or metal before preparing a solution standard. The analyst must be assured that the purity, stoichiometry, and assay of the chemical are known. These terms have different meanings, and each has an important influence. This report is intended to assist the analyst in the selection and use of chemical standards for instrumental calibration. Purity, stoichiometry, and preparation of solutions for different purposes are discussed, and a critical evaluation of the best materials available for each element is presented for use in preparing solutions or calibration standards. Information on the chemical form, source, purity, drying, and appropriate precautions is given. In some cases, multiple sources or chemical forms are available. Certain radioactive elements, the transuranic elements, and the noble gases are not considered

  20. Financial model calibration using consistency hints.

    Science.gov (United States)

    Abu-Mostafa, Y S

    2001-01-01

    We introduce a technique for forcing the calibration of a financial model to produce valid parameters. The technique is based on learning from hints. It converts simple curve fitting into genuine calibration, where broad conclusions can be inferred from parameter values. The technique augments the error function of curve fitting with consistency hint error functions based on the Kullback-Leibler distance. We introduce an efficient EM-type optimization algorithm tailored to this technique. We also introduce other consistency hints, and balance their weights using canonical errors. We calibrate the correlated multifactor Vasicek model of interest rates, and apply it successfully to Japanese Yen swaps market and US dollar yield market.

  1. Novel diffusion tensor imaging technique reveals developmental streamline volume changes in the corticospinal tract associated with leg motor control.

    Science.gov (United States)

    Kamson, David O; Juhász, Csaba; Chugani, Harry T; Jeong, Jeong-Won

    2015-04-01

    Diffusion tensor imaging (DTI) has expanded our knowledge of corticospinal tract (CST) anatomy and development. However, previous developmental DTI studies assessed the CST as a whole, overlooking potential differences in development of its components related to control of the upper and lower extremities. The present cross-sectional study investigated age-related changes, side and gender differences in streamline volume of the leg- and hand-related segments of the CST in children. DTI data of 31 children (1-14 years; mean age: 6±4 years; 17 girls) with normal conventional MRI were analyzed. Leg- and hand-related CST streamline volumes were quantified separately, using a recently validated novel tractography approach. CST streamline volumes on both sides were compared between genders and correlated with age. Higher absolute streamline volumes were found in the left leg-related CST compared to the right (p=0.001) without a gender effect (p=0.4), whereas no differences were found in the absolute hand-related CST volumes (p>0.4). CST leg-related streamline volumes, normalized to hemispheric white matter volumes, declined with age in the right hemisphere only (R=-.51; p=0.004). Absolute leg-related CST streamline volumes showed similar, but slightly weaker correlations. Hand-related absolute or normalized CST streamline volumes showed no age-related variations on either side. These results suggest differential development of CST segments controlling hand vs. leg movements. Asymmetric volume changes in the lower limb motor pathway may be secondary to gradually strengthening left hemispheric dominance and is consistent with previous data suggesting that footedness is a better predictor of hemispheric lateralization than handedness. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  2. Nonlinear propagation model for ultrasound hydrophones calibration in the frequency range up to 100 MHz.

    Science.gov (United States)

    Radulescu, E G; Wójcik, J; Lewin, P A; Nowicki, A

    2003-06-01

    To facilitate the implementation and verification of the new ultrasound hydrophone calibration techniques described in the companion paper (somewhere in this issue) a nonlinear propagation model was developed. A brief outline of the theoretical considerations is presented and the model's advantages and disadvantages are discussed. The results of simulations yielding spatial and temporal acoustic pressure amplitude are also presented and compared with those obtained using KZK and Field II models. Excellent agreement between all models is evidenced. The applicability of the model in discrete wideband calibration of hydrophones is documented in the companion paper somewhere in this volume.

  3. Detector characterization for efficiency calibration in different measurement geometries

    International Nuclear Information System (INIS)

    Toma, M.; Dinescu, L.; Sima, O.

    2005-01-01

    In order to perform an accurate efficiency calibration for different measurement geometries a good knowledge of the detector characteristics is required. The Monte Carlo simulation program GESPECOR is applied. The detector characterization required for Monte Carlo simulation is achieved using the efficiency values obtained from measuring a point source. The point source was measured in two significant geometries: the source placed in a vertical plane containing the vertical symmetry axis of the detector and in a horizontal plane containing the centre of the active volume of the detector. The measurements were made using gamma spectrometry technique. (authors)

  4. Soucreless efficiency calibration for HPGe detector based on medical images

    International Nuclear Information System (INIS)

    Chen Chaobin; She Ruogu; Xiao Gang; Zuo Li

    2012-01-01

    Digital phantom of patient and region of interest (supposed to be filled with isotropy volume source) are built from medical CT images. They are used to calculate the detection efficiency of HPGe detectors located outside of human body by sourceless calibration method based on a fast integral technique and MCNP code respectively, and the results from two codes are in good accord besides a max difference about 5% at intermediate energy region. The software produced in this work are in better behavior than Monte Carlo code not only in time consume but also in complexity of problem to solve. (authors)

  5. Inversion of calcite twin data for paleostress orientations and magnitudes: A new technique tested and calibrated on numerically-generated and natural data

    Science.gov (United States)

    Parlangeau, Camille; Lacombe, Olivier; Schueller, Sylvie; Daniel, Jean-Marc

    2018-01-01

    The inversion of calcite twin data is a powerful tool to reconstruct paleostresses sustained by carbonate rocks during their geological history. Following Etchecopar's (1984) pioneering work, this study presents a new technique for the inversion of calcite twin data that reconstructs the 5 parameters of the deviatoric stress tensors from both monophase and polyphase twin datasets. The uncertainties in the parameters of the stress tensors reconstructed by this new technique are evaluated on numerically-generated datasets. The technique not only reliably defines the 5 parameters of the deviatoric stress tensor, but also reliably separates very close superimposed stress tensors (30° of difference in maximum principal stress orientation or switch between σ3 and σ2 axes). The technique is further shown to be robust to sampling bias and to slight variability in the critical resolved shear stress. Due to our still incomplete knowledge of the evolution of the critical resolved shear stress with grain size, our results show that it is recommended to analyze twin data subsets of homogeneous grain size to minimize possible errors, mainly those concerning differential stress values. The methodological uncertainty in principal stress orientations is about ± 10°; it is about ± 0.1 for the stress ratio. For differential stresses, the uncertainty is lower than ± 30%. Applying the technique to vein samples within Mesozoic limestones from the Monte Nero anticline (northern Apennines, Italy) demonstrates its ability to reliably detect and separate tectonically significant paleostress orientations and magnitudes from naturally deformed polyphase samples, hence to fingerprint the regional paleostresses of interest in tectonic studies.

  6. Piezoelectric trace vapor calibrator

    International Nuclear Information System (INIS)

    Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

    2006-01-01

    The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 μg/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process

  7. Intercomparison and calibration of dose calibrators used in nuclear medicine facilities

    CERN Document Server

    Costa, A M D

    2003-01-01

    The aim of this work was to establish a working standard for intercomparison and calibration of dose calibrators used in most of nuclear medicine facilities for the determination of the activity of radionuclides administered to patients in specific examinations or therapeutic procedures. A commercial dose calibrator, a set of standard radioactive sources, and syringes, vials and ampoules with radionuclide solutions used in nuclear medicine were utilized in this work. The commercial dose calibrator was calibrated for radionuclide solutions used in nuclear medicine. Simple instrument tests, such as linearity response and variation response with the source volume at a constant source activity concentration were performed. This instrument may be used as a reference system for intercomparison and calibration of other activity meters, as a method of quality control of dose calibrators utilized in nuclear medicine facilities.

  8. Calibration and intercomparison methods of dose calibrators used in nuclear medicine facilities

    International Nuclear Information System (INIS)

    Costa, Alessandro Martins da

    1999-01-01

    Dose calibrators are used in most of the nuclear medicine facilities to determine the amount of radioactivity administered to a patient in a particular investigation or therapeutic procedure. It is therefore of vital importance that the equipment used presents good performance and is regular;y calibrated at a authorized laboratory. This occurs of adequate quality assurance procedures are carried out. Such quality control tests should be performed daily, other biannually or yearly, testing, for example, its accuracy and precision, the reproducibility and response linearity. In this work a commercial dose calibrator was calibrated with solution of radionuclides used in nuclear medicine. Simple instrument tests, such as response linearity and the response variation of the source volume increase at a constant source activity concentration, were performed. This instrument can now be used as a working standard for calibration of other dose calibrators/ An intercomparison procedure was proposed as a method of quality control of dose calibrators used in nuclear medicine facilities. (author)

  9. Interlaboratory comparison of techniques for measuring lung burdens of low-energy X-ray emitters. Part of a coordinated programme on the calibration of burdens of inhaled plutonium by external counting

    International Nuclear Information System (INIS)

    Newton, D.; Fry, F.A.; Taylor, B.T.; Eagle, M.C.; Sharma, R.C.

    1978-02-01

    An interlaboratory exercise has been conducted to assess techniques of detection and calibration in the direct measurement of lung contamination with plutonium and other nuclides emitting only low-energy X-rays. Three volunteers, of small, intermediate and large physique, inhaled an aerosol incorporating Pd-103, a 20-keV X-ray emitter, and visited 13 other laboratories in the UK, Europe and North America. Participants in the exercise were asked to estimate each subject's lung content, using their procedures for assessing burdens of plutonium, and their estimates were compared with values derived independently from measurements of Cr-51, also incorporated in the inhaled particles, by gamma-ray spectrometry. Laboratories' calibration procedures were in most cases based on elaborate thorax phantoms, and these generally led to underestimates of the subjects' contents, in some instances by a factor of three or more; only one such laboratory produced estimates in satisfactory agreement with the independently-known values. The ''phoswich'' detectors, employed by most participants, appeared to be more sensitive than gas counters. If a standard configuration were required, offering the highest sensitivity in most situations, the choice would be a pair of 12-cm diameter phoswich detectors viewing the left and right anterior surfaces of the upper thorax. No improvement in sensitivity would result from increasing the size, although larger units may offer other advantages

  10. Calibration of radionuclides with decay trough beta emission or electron capture by liquid scintillation technique; Calibracao de radionuclideos que decaem por emissao beta ou por captura eletronica pela tecnica de cintilacao liquida

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Jamir dos Santos

    2000-02-01

    In this work is reported a methodology a methodology for pure beta and electron capture radionuclides standardization, suing liquid scintillation technique. In this sense the CIEMAT/NIST method, recently utilized by international laboratories, was implemented and the lack in the Laboratorio Nacional das Radiacoes Ionizantes - LNMRI, of the Comissao Nacional de Energia Nuclear - CNEN, for adequate methodology to standardize this kind if radionuclides was filled, fact that was not present with alpha and gamma radionuclides. The implementation procedure evaluation was provided by concentration activity determination of the following radionuclides: {sup 14} C and {sup 90} Sr, pure beta emitters; {sup 55} Fe, electron capture decay; {sup 204} Tl, electron capture and beta decay and {sup 60} Co, beta-gamma emitter. In this way, a careful analysis of the implementation procedure with these radionuclides types, ranging on a broad energy spectral, was possible. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. Besides this intercomparisons, one was provided with a {sup 204} Tl solution, utilized in the international comparison recently promoted by BIPM, and another one with a {sup 60} C solution calibrated in LNMRI/CNEN previously by a relative calibration system, with a well type pressurized ionization chamber, and an absolute beta-gamma coincidence system, with a pill-box type proportional counter 4 {pi} geometry, coupled with a scintillator system with a sodium iodide cristal of 4x4 inches. The comparisons among LNMRI/CNEN results and the reference values, showed a small deviation of 1,32% for {sup 14} C, 0,40% for {sup 60} Co, 1,12% for {sup 55} Fe, 0,10% for {sup 90} Sr and 0,73% for {sup

  11. Variance of measurements from a calibration function derived from data which exhibit run-to-run differences

    International Nuclear Information System (INIS)

    Liebetrau, A.M.

    1985-01-01

    The volume of liquid in a nuclear process tank is determined from a calibration equation which expresses volume as a function of liquid level. Successive calibration runs are made to obtain data from which to estimate either the calibration function or its inverse. For tanks equipped with high-precision measurement systems to determine liquid level, it frequently happens that run-to-run differences due to uncontrolled or uncontrollable ambient conditions are large relative to within-run measurement errors. In the strict sense, a calibration function cannot be developed from data which exhibit significant run-to-run differences. In practice, run-to-run differences are ignored when they are small relative to the accuracy required for measurements of the tank's contents. The use of standard statistical techniques in this situation can result in variance estimates which severely underestimate the actual uncertainty in volume measurements. This paper gives a method whereby reasonable estimates of the calibration uncertainty in volume determinations can be obtained in the presence of statistically significant run-to-run variability. 4 references, 3 figures, 1 table

  12. Calibração da técnica de moiré aplicada a perfilometria de protótipos mecânicos Calibration method applied to a moiré technique in experiments of mechanical archetypes

    Directory of Open Access Journals (Sweden)

    Túlio Seabra Gomes

    2009-04-01

    Full Text Available A perfilometria é uma técnica amplamente utilizada na construção de mapas e gráficos de relevos aplicados a uma vasta área do conhecimento. Frente às necessidades de suprir a demanda da indústria e da área de desenvolvimento de protótipos quanto a técnicas não invasivas na investigação da superfície de materiais em geral, o presente trabalho buscou propor uma metodologia de calibração aplicada à técnica de moiré para investigações perfilométricas em protótipos mecânicos buscando baixos custos e flexibilidade. A técnica de moiré consiste na comparação de dois retículos periódicos, onde um segue o comportamento da superfície do objeto (retículo modelo - Rm e outro não está deformado, seguindo o comportamento de um plano de referência, (retículo de referência - Rr. A luz que passa entre os retículos se sobrepõe formando padrões de moiré ou franjas de moiré que se comportam como ondas senoidais. Nos ensaios de calibração, usou-se um cone de relevo conhecido para a determinação de uma constante de correção de mapas gerados digitalmente. Os ensaios realizados aplicaram a metodologia para a determinação do perfil de um mouse de computador e para a determinação da deformação de uma chapa metálica. A metodologia proposta para a calibração da técnica de moiré mostrouse capaz de realizar os mapeamentos, com resolução máxima na ordem de centésimos de milímetros, podendo então ser usada em aplicações com níveis de precisão inferiores a essa ordem.Profilometry is a measurement technique widely used in map and relief graphic construction, being applied to vast areas of knowledge. The aim of the present investigation was to introduce a calibration method applied to a moiré technique in experiments of mechanical archetypes, with low cost and flexibility, due to the need for supplying demands from both industry and mechanical archetype development for non-invasive techniques. The moir

  13. Parotid gland tumors: A comparison of postoperative radiotherapy techniques using three dimensional (3D) dose distributions and dose-volume histograms (DVHs)

    International Nuclear Information System (INIS)

    Yaparpalvi, Ravindra; Fontenla, Doracy P.; Tyerech, Sangeeta K.; Boselli, Lucia R.; Beitler, Jonathan J.

    1998-01-01

    Purpose: To compare different treatment techniques for unilateral treatment of parotid gland tumors. Methods and Materials: The CT-scans of a representative parotid patient were used. The field size was 9 x 11 cm, the separation was 15.5 cm, and the prescription depth was 4.5 cm. Using 3D dose distributions, tissue inhomogeneity corrections, scatter integration (for photons) and pencil beam (for electrons) algorithms and dose-volume histogram (DVH), nine treatment techniques were compared. [1] unilateral 6 MV photons [2] unilateral 12 MeV electrons [3] unilateral 16 MeV electrons [4] an ipsilateral wedge pair technique using 6 MV photons [5] a 3-field AP (wedged), PA (wedged) and lateral portal technique using 6 MV photons [6] a mixed beam technique using 6 MV photons and 12 MeV electrons (1:4 weighting) [7] a mixed beam technique using 6 MV photons and 16 MeV electrons (1:4 weighting) [8] a mixed beam technique using 18 MV photons and 20 MeV electrons (2:3 weighting) [9] a mixed beam technique using 18 MV photons and 20 MeV electrons (1:1 weighting). Results: Using dose-volume histograms to evaluate the dose to the contralateral parotid gland, the percentage of contralateral parotid volume receiving ≥ 30% of the prescribed dose was 100% for techniques [1], [8] and [9], and < 5% for techniques [2] through [7]. Evaluating the 'hottest' 5 cc of the ipsilateral mandible and temporal lobes, the hot spots were: 152% and 150% for technique [2], 132% and 130% for technique [6]. Comparing the exit doses, techniques [1], [8] and [9] contributed to ≥ 50% of the prescribed dose to the contralateral mandible and the temporal lobes. Only techniques [2] and [6] kept the highest point doses to both the brain stem and the spinal cord below 50% of the prescribed dose. Conclusion: The single photon lateral field [1] and the mixed electron-photon beams [8] and [9] are not recommended treatment techniques for unilateral parotid irradiation because of high doses delivered to the

  14. Studying the method of linearization of exponential calibration curves

    International Nuclear Information System (INIS)

    Bunzh, Z.A.

    1989-01-01

    The results of study of the method for linearization of exponential calibration curves are given. The calibration technique and comparison of the proposed method with piecewise-linear approximation and power series expansion, are given

  15. Space shuttle/food system. Volume 2, Appendix C: Food cooling techniques analysis. Appendix D: Package and stowage: Alternate concepts analysis

    Science.gov (United States)

    1974-01-01

    The relative penalties associated with various techniques for providing an onboard cold environment for storage of perishable food items, and for the development of packaging and vehicle stowage parameters were investigated in terms of the overall food system design analysis of space shuttle. The degrees of capability for maintaining both a 40 F to 45 F refrigerated temperature and a 0 F and 20 F frozen environment were assessed for the following cooling techniques: (1) phase change (heat sink) concept; (2) thermoelectric concept; (3) vapor cycle concept; and (4) expendable ammonia concept. The parameters considered in the analysis were weight, volume, and spacecraft power restrictions. Data were also produced for packaging and vehicle stowage parameters which are compatible with vehicle weight and volume specifications. Certain assumptions were made for food packaging sizes based on previously generated space shuttle menus. The results of the study are shown, along with the range of meal choices considered.

  16. Calibration of Geophone Micro-seismic Sensors

    International Nuclear Information System (INIS)

    Bowden, G.

    2005-01-01

    This note describes a simple lab bench technique for calibrating the sensitivity and dynamics of the Mark Products L4C geophones used at SLAC for measuring microseismic ground motion and mechanical vibrations of accelerator support structures. Calibration results for SLAC's three L4C geophones are recorded

  17. Overview of hypersonic CFD code calibration studies

    Science.gov (United States)

    Miller, Charles G.

    1987-01-01

    The topics are presented in viewgraph form and include the following: definitions of computational fluid dynamics (CFD) code validation; climate in hypersonics and LaRC when first 'designed' CFD code calibration studied was initiated; methodology from the experimentalist's perspective; hypersonic facilities; measurement techniques; and CFD code calibration studies.

  18. Surgeons’ Volume-Outcome Relationship for Lobectomies and Wedge Resections for Cancer Using Video-Assisted Thoracoscopic Techniques

    Directory of Open Access Journals (Sweden)

    Guy David

    2012-01-01

    Full Text Available This study examined the effect of surgeons’ volume on outcomes in lung surgery: lobectomies and wedge resections. Additionally, the effect of video-assisted thoracoscopic surgery (VATS on cost, utilization, and adverse events was analyzed. The Premier Hospital Database was the data source for this analysis. Eligible patients were those of any age undergoing lobectomy or wedge resection using VATS for cancer treatment. Volume was represented by the aggregate experience level of the surgeon in a six-month window before each surgery. A positive volume-outcome relationship was found with some notable features. The relationship is stronger for cost and utilization outcomes than for adverse events; for thoracic surgeons as opposed to other surgeons; for VATS lobectomies rather than VATS wedge resections. While there was a reduction in cost and resource utilization with greater experience in VATS, these outcomes were not associated with greater experience in open procedures.

  19. Vessel calibration for accurate material accountancy at RRP

    International Nuclear Information System (INIS)

    Yanagisawa, Yuu; Ono, Sawako; Iwamoto, Tomonori

    2004-01-01

    RRP has a 800t·Upr capacity a year to re-process, where would be handled a large amount of nuclear materials as solution. A large scale plant like RRP will require accurate materials accountancy system, so that the vessel calibration with high-precision is very important as initial vessel calibration before operation. In order to obtain the calibration curve, it is needed well-known each the increment volume related with liquid height. Then we performed at least 2 or 3 times run with water for vessel calibration and careful evaluation for the calibration data should be needed. We performed vessel calibration overall 210 vessels, and the calibration of 81 vessels including IAT and OAT were held under presence of JSGO and IAEA inspectors taking into account importance on the material accountancy. This paper describes outline of the initial vessel calibration and calibration results based on back pressure measurement with dip tubes. (author)

  20. Establishment of Accurate Calibration Curve for National Verification at a Large Scale Input Accountability Tank in RRP - For Strengthening State System for Meeting Safeguards Obligation

    International Nuclear Information System (INIS)

    Goto, Y.; Kato, T.; Nidaira, K.

    2010-01-01

    Tanks are installed in a reprocessing plant for spent fuel in order to account solution of nuclear material. The careful measurement of volume in tanks is crucial to implement accurate accounting of nuclear material. The calibration curve related with the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes in tanks. More than one calibration curves depending on the height are commonly applied for each tank, but it's not explicitly decided how many segments are used, where to select segment, or what order of polynomial curve. Here we present the rational construction technique of giving optimum calibration curves and their characteristics. The tank calibration work has been conducted in the course of contract with Japan Safeguards Office (JSGO) about safeguards information treatment. (author)

  1. Parotid gland tumors: a comparison of postoperative radiotherapy techniques using three dimensional (3-D) dose distributions and dose-volume histograms (DVH)

    International Nuclear Information System (INIS)

    Yaparpalvi, R.; Tyerech, S.K.; Boselli, L.R.; Fontenla, D.P.; Beitler, J.J.; Vikram, B.

    1996-01-01

    Purpose/Objective: To compare different treatment techniques for unilateral treatment of parotid gland tumors. Materials and Methods: Twenty patients previously treated postoperatively for parotid gland tumors were retrospectively reviewed. Average field size was 9 x 11 cm, average separation was 15.5 cm, and the average prescription depth was 4.5 cm. Using 3-D dose distributions, tissue inhomogeneity corrections, scatter integration (for photons) and pencil beam (for electrons) algorithms and DVH, nine treatment techniques were compared using a representative patient. The treatment techniques investigated were: [1] unilateral 6 MV photons. [2] unilateral 12 MeV electrons. [3] unilateral 16 MeV electrons. [4] a ipsilateral wedge pair technique using 6 MV photons and a 45-degree wedge. [5] a 3-field AP (wedged), PA (wedged) and lateral portal technique using 6 MV photons. [6] a mixed beam technique using 6 MV photons and 12 MeV electrons (1:4 weighting). [7] a mixed beam technique using 6 MV photons and 16 MeV electrons (1:4 weighting). [8] a mixed beam technique using 18 MV photons and 20 MeV electrons (2:3 weighting). [9] a mixed beam technique using 18 MV photons and 20 MeV electrons (1:1 weighting). Results: Using dose-volume histograms to evaluate the dose to the contralateral parotid gland, the percentage of contralateral parotid volume receiving ≥30% of the prescribed dose was 100% for techniques [1], [8] and [9], and <5% for techniques [2] through [7]. Evaluating the 'hottest' 5 cc of the ipsilateral mandible and temporal lobes, the hot spots were: 152% and 150% for technique [2], 132% and 130% for technique [6]. Comparing the exit doses, techniques [1] and [8] contributed to ≥50% of the prescribed dose to the contralateral mandible and the temporal lobes. Only techniques [2] and [6] kept the highest point doses to both the brain stem and the spinal cord below 50% of the prescribed dose. Conclusion: The single photon lateral field [1] and the mixed

  2. Environmental effects of energy production and utilization in the U.S. Volume 3. Techniques for controlling emissions

    International Nuclear Information System (INIS)

    Newkirk, H.W.

    1976-01-01

    Technological, social, economic and political techniques for controlling emission are summarized for environmental pollutants introduced into air, water and land resources. Chemical, radiological and physical factors are discussed

  3. Influence of operator experience and PCI volume on transfemoral access techniques: A collaboration of international cardiovascular societies.

    Science.gov (United States)

    Nelson, Daniel W; Damluji, Abdulla A; Patel, Nish; Valgimigli, Marco; Windecker, Stephan; Byrne, Robert; Nolan, James; Patel, Tejas; Brilakis, Emmanouil; Banerjee, Subhash; Mayol, Jorge; Cantor, Warren J; Alfonso, Carlos E; Rao, Sunil V; Moscucci, Mauro; Cohen, Mauricio G

    2018-03-01

    Transfemoral access (TFA) is widely used for coronary angiography and percutaneous coronary intervention (PCI). The influence of operator age, gender, experience, and procedural volume on performance of femoral arterial access has not been studied. A survey instrument was developed and distributed via e-mail from professional societies to interventional cardiologists worldwide from March to December 2016. A total of 988 physicians from 88 countries responded to the survey. TFA is the preferred approach for patients with cardiogenic shock, left main or bifurcation PCI, and procedures with mechanical circulatory support. Older (PCI volume operators (PCI: 57.3%; 100-299 PCI: 58.7%; ≥300 PCI: 64.3%, pPCI volume operators (≥300 PCI: 64.1%; 100-299 PCI: 72.6%; PCI: 67.9%, pPCI volume interventional cardiologists prefer not to use imaging for femoral access or perform femoral angiography during TF procedures. These data highlight opportunities to further reduce TFA complications. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Identification of variables for site calibration and power curve assessment in complex terrain. Task 8, a literature survey on theory and practice of parameter identification, specification and estimation (ISE) techniques

    Energy Technology Data Exchange (ETDEWEB)

    Verhoef, J.P.; Leendertse, G.P. [ECN Wind, Petten (Netherlands)

    2001-04-01

    This document presents the literature survey results on Identification, Specification and Estimation (ISE) techniques for variables within the SiteParIden project. Besides an overview of the different general techniques also an overview is given on EU funded wind energy projects where some of these techniques have been applied more specifically. The main problem in applications like power performance assessment and site calibration is to establish an appropriate model for predicting the considered dependent variable with the aid of measured independent (explanatory) variables. In these applications detailed knowledge on what the relevant variables are and how their precise appearance in the model would be is typically missing. Therefore, the identification (of variables) and the specification (of the model relation) are important steps in the model building phase. For the determination of the parameters in the model a reliable variable estimation technique is required. In EU funded wind energy projects the linear regression technique is the most commonly applied tool for the estimation step. The linear regression technique may fail in finding reliable parameter estimates when the model variables are strongly correlated, either due to the experimental set-up or because of their particular appearance in the model. This situation of multicollinearity sometimes results in unrealistic parameter values, e.g. with the wrong algebraic sign. It is concluded that different approaches, like multi-binning can provide a better way of identifying the relevant variables. However further research in these applications is needed and it is recommended that alternative methods (neural networks, singular value decomposition etc.) should also be tested on their usefulness in a succeeding project. Increased interest in complex terrains, as feasible locations for wind farms, has also emphasised the need for adequate models. A common standard procedure to prescribe the statistical

  5. Large-volume constant-concentration sampling technique coupling with surface-enhanced Raman spectroscopy for rapid on-site gas analysis.

    Science.gov (United States)

    Zhang, Zhuomin; Zhan, Yisen; Huang, Yichun; Li, Gongke

    2017-08-05

    In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH 4 + strategy for ethylene and SO 2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO 2 from fruits. It was satisfied that trace ethylene and SO 2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO 2 during the entire LVCC sampling process were proved to be gas targets from real samples by SERS. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Radioactivity measurement of 18F in 16 ml vials for calibration of radionuclide calibrators

    International Nuclear Information System (INIS)

    Wurdiyanto, Gatot; Marsoem, Pujadi; Candra, Hermawan; Wijono, Paidi

    2012-01-01

    Fluorine-18 is obtained through the reaction 18 O(p, n) 18 F using a cyclotron that is situated in a hospital in Jakarta. Standardization of the 18 F solution is performed by gamma spectrometry using calibration sources of 152 Eu, 60 Co and 137 Cs that have traceability to the International System of units (SI). The activities in the 16 ml vials that were used for calibrating the radionuclide calibrators were between 1 and 2 GBq, with expanded uncertainties of 3.8%. The expanded uncertainty, at a coverage factor of k=2, on the derived calibration factor for the radionuclide calibrator was 6.6%. - Highlights: ► PTKMR–BATAN as a NMI of Indonesia is required to have procedures to calibrate the radionuclide calibrators. ► Standardizations were carried out on a solution of [ 18 F]FDG using gamma spectrometry. ► The volume of 18 F solutions used was 16 ml because this is the volume often used in hospitals. ► The Secondary Standard ionization chamber is a CRC-7BT Capintec radionuclide calibrator. ► A dial setting for 16 ml of [ 18 F]FDG solution in a vial is 443 for the Capintec dose calibrator.

  7. Limits of dose escalation in lung cancer: a dose-volume histogram analysis comparing coplanar and non-coplanar techniques

    Energy Technology Data Exchange (ETDEWEB)

    Derycke, S; Van Duyse, B; Schelfhout, J; De Neve, W

    1995-12-01

    To evaluate the feasibility of dose escalation in radiotherapy of inoperable lung cancer, a dose-volume histogram analysis was performed comparing standard coplanar (2D) with non-coplanar (3D) beam arrangements on a non-selected group of 20 patients planned by Sherouse`s GRATISTM 3D-planning system. Serial CT-scanning was performed and 2 Target Volumes (Tvs) were defined. Gross Tumor Volume (GTV) defined a high-dose Target Volume (TV-1). GTV plus location of node stations with > 10% probability of invasion (Minet et al.) defined an intermediate-dose Target Volume (TV-2). However, nodal regions which are incompatible with cure were excluded from TV-2. These are ATS-regions 1, 8, 9 and 14 all left and right as well as heterolateral regions. For 3D-planning, Beam`s Eye View selected (by an experienced planner) beam arrangements were optimised using Superdot, a method of target dose-gradient annihilation developed by Sherouse. A second 3D-planning was performed using 4 beam incidences with maximal angular separation. The linac`s isocenter for the optimal arrangement was located at the geometrical center of gravity of a tetraheder, the tetraheder`s comers being the consecutive positions of the virtual source. This ideal beam arrangement was approximated as close as possible, taking into account technical limitations (patient-couch-gantry collisions). Criteria for tolerance were met if no points inside the spinal cord exceeded 50 Gy and if at least 50% of the lung volume received less than 20Gy. If dose regions below 50 Gy were judged acceptable at TV-2, 2D- as well as 3D-plans allow safe escalation to 80 Gy at TV-1. When TV-2 needed to be encompassed by isodose surfaces exceeding 50Gy, 3D-plans were necessary to limit dose at the spinal cord below tolerance. For large TVs dose is limited by lung tolerance for 3D-plans. An analysis (including NTCP-TCP as cost functions) of rival 3D-plans is being performed.

  8. Radiation protection dosimetry and calibrations

    International Nuclear Information System (INIS)

    Verhavere, Ph.

    2007-01-01

    At the SCK-CEN different specialised services are delivered for a whole range of external and internal customers in the radiation protection area. For the expertise group of radiation protection dosimetry and calibrations, these services are organized in four different laboratories: dosimetry, anthropogammametry, nuclear calibrations and non-nuclear calibrations. The services are given by a dedicated technical staff who has experience in the handling of routine and specialised cases. The scientific research that is performed by the expertise group makes sure that state-of-the-art techniques are being used, and that constant improvements and developments are implemented. Quality Assurance is an important aspect for the different services, and accreditation according national and international standards is achieved for all laboratories

  9. Mechanics of log calibration

    International Nuclear Information System (INIS)

    Waller, W.C.; Cram, M.E.; Hall, J.E.

    1975-01-01

    For any measurement to have meaning, it must be related to generally accepted standard units by a valid and specified system of comparison. To calibrate well-logging tools, sensing systems are designed which produce consistent and repeatable indications over the range for which the tool was intended. The basics of calibration theory, procedures, and calibration record presentations are reviewed. Calibrations for induction, electrical, radioactivity, and sonic logging tools will be discussed. The authors' intent is to provide an understanding of the sources of errors, of the way errors are minimized in the calibration process, and of the significance of changes in recorded calibration data

  10. Calibration issues for neutron diagnostics

    International Nuclear Information System (INIS)

    Sadler, G.J.; Adams, J.M.; Barnes, C.W.

    1997-01-01

    The performance of diagnostic systems are limited by their weakest constituents, including their calibration issues. Neutron diagnostics are notorious for problems encountered while determining their absolute calibrations, due mainly to the nature of the neutron transport problem. In order to facilitate the determination of an accurate and precise calibration, the diagnostic design should be such as to minimize the scattered neutron flux. ITER will use a comprehensive set of neutron diagnostics--comprising radial and vertical neutron cameras, neutron spectrometers, a neutron activation system and internal and external fission chambers--to provide accurate measurements of fusion power and power densities as a function of time. The calibration of such an important diagnostic system merits careful consideration. Some thoughts have already been given to this subject during the conceptual design phase in relation to the time-integrated neutron activation and time-dependent neutron yield monitors. However, no overall calibration strategy has been worked out so far. This paper represents a first attempt to address this vital issue. Experience gained from present large tokamaks (JET, TFTR and JT60U) and proposals for ITER are reviewed. The need to use a 14-MeV neutron generator as opposed to radioactive sources for in-situ calibration of D-T diagnostics will be stressed. It is clear that the overall absolute determination of fusion power will have to rely on a combination of nuclear measuring techniques, for which the provision of accurate and independent calibrations will constitute an ongoing process as ITER moves from one phase of operation to the next

  11. Calibration and evaluation of neutron moisturemeter

    International Nuclear Information System (INIS)

    Tang Zhangxiong; Hu Jiangchao; Sun Laiyan; Wang Huaihui; Wu Weixue

    1992-02-01

    Factors influencing the calibration curve of neutron moisture meter, such as soil type, texture, volume weight and depth, were studied. When the soil bulk density water content is between 15% to 45%, the calibration curve is approximately a straight line, and the intercept and slope are only influenced by the above factors. The growing plants also influence the calibration curve slightly. The measuring error for top soil (< 20 cm) is larger. The relative error between neutron method and weighing method is about 8%. The neutron method has many advantages such as non-interfering, simple, fast and non-time-delay

  12. Procedures for treating common cause failures in safety and reliability studies: Volume 2, Analytic background and techniques: Final report

    International Nuclear Information System (INIS)

    Mosleh, A.; Fleming, K.N.; Parry, G.W.; Paula, H.M.; Worledge, D.H.; Rasmuson, D.M.

    1988-12-01

    This report presents a framework for the inclusion of the impact of common cause failures in risk and reliability evaluations. Common cause failures are defined as that subset of dependent failures for which causes are not explicitly included in the logic model as basic events. The emphasis here is on providing procedures for a practical, systematic approach that can be used to perform and clearly document the analysis. The framework and the methods discussed for performing the different stages of the analysis integrate insights obtained from engineering assessments of the system and the historical evidence from multiple failure events into a systematic, reproducible, and defensible analysis. This document, Volume 2, contains a series of appendices that provide additional background and methodological detail on several important topics discussed in Volume 1

  13. Electromagnetic Calorimeter Calibration with $\\pi^{0}$

    CERN Multimedia

    Puig Navarro, A

    2009-01-01

    Several methods can be used in order to achieve precise calibration of the LHCb Electromagnetic Calorimeter (ECAL) once reasonable cell equalization has been reached. At low transverse energy, the standard calibration procedure is an iterative method based on the fit of the $\\gamma\\gamma$ invariant mass distribution for each cell of the decay $\\pi^{0}\\to\\gamma\\gamma$ with resolved photons. A new technique for generating the combinatorial background of such decays directly from data has been developed. Knowledge of the background could allow an alternative calibration method based on a event by event fit of the same $\\gamma\\gamma$ invariant mass distribution where contributions from groups of cells are considered in a single fit. The background generation procedure and this possible new calibration method are presented in this poster, in addition to an overview of the LHCb Calorimetry system and ECAL calibration techniques.

  14. Environmental effects of energy production and utilization in the U. S. Volume 3. Techniques for controlling emissions

    Energy Technology Data Exchange (ETDEWEB)

    Newkirk, H.W. (comp.)

    1976-06-14

    Technological, social, economic and political techniques for controlling emission are summarized for environmental pollutants introduced into air, water and land resources. Chemical, radiological and physical factors are discussed. (PCS)

  15. Bivalve fouling of nuclear power plant service-water systems. Volume 2. Current status of biofouling surveillance and control techniques

    International Nuclear Information System (INIS)

    Daling, P.M.; Johnson, K.I.

    1985-03-01

    This report describes the current status of techniques for detection and control of cooling-water system fouling by bivalve mollusks at nuclear power plants. The effectiveness of these techniques is evaluated on the basis of information gathered from a literature review and in interviews with nuclear power plant personnel. Biofouling detection techniques examined in this report include regular maintenance, in-service inspection, and testing. Generally, these methods have been inadequate for detecting biofouling. Recommendations for improving biofouling detection capabilities are presented. Biofouling prevention (or control) methods that are examined in this report include intake screen systems, thermal treatment, preventive maintenance, chemical treatment alternatives, and antifoulant coatings. Recommendations for improving biofouling control methods at operating nuclear power plants are presented. Additional techniques that could be implemented at future power plants or that require further research are also described

  16. Synthesis Polarimetry Calibration

    Science.gov (United States)

    Moellenbrock, George

    2017-10-01

    Synthesis instrumental polarization calibration fundamentals for both linear (ALMA) and circular (EVLA) feed bases are reviewed, with special attention to the calibration heuristics supported in CASA. Practical problems affecting modern instruments are also discussed.

  17. ORNL calibrations facility

    International Nuclear Information System (INIS)

    Berger, C.D.; Gupton, E.D.; Lane, B.H.; Miller, J.H.; Nichols, S.W.

    1982-08-01

    The ORNL Calibrations Facility is operated by the Instrumentation Group of the Industrial Safety and Applied Health Physics Division. Its primary purpose is to maintain radiation calibration standards for calibration of ORNL health physics instruments and personnel dosimeters. This report includes a discussion of the radioactive sources and ancillary equipment in use and a step-by-step procedure for calibration of those survey instruments and personnel dosimeters in routine use at ORNL

  18. Large-volume constant-concentration sampling technique coupling with surface-enhanced Raman spectroscopy for rapid on-site gas analysis

    Science.gov (United States)

    Zhang, Zhuomin; Zhan, Yisen; Huang, Yichun; Li, Gongke

    2017-08-01

    In this work, a portable large-volume constant-concentration (LVCC) sampling technique coupling with surface-enhanced Raman spectroscopy (SERS) was developed for the rapid on-site gas analysis based on suitable derivatization methods. LVCC sampling technique mainly consisted of a specially designed sampling cell including the rigid sample container and flexible sampling bag, and an absorption-derivatization module with a portable pump and a gas flowmeter. LVCC sampling technique allowed large, alterable and well-controlled sampling volume, which kept the concentration of gas target in headspace phase constant during the entire sampling process and made the sampling result more representative. Moreover, absorption and derivatization of gas target during LVCC sampling process were efficiently merged in one step using bromine-thiourea and OPA-NH4+ strategy for ethylene and SO2 respectively, which made LVCC sampling technique conveniently adapted to consequent SERS analysis. Finally, a new LVCC sampling-SERS method was developed and successfully applied for rapid analysis of trace ethylene and SO2 from fruits. It was satisfied that trace ethylene and SO2 from real fruit samples could be actually and accurately quantified by this method. The minor concentration fluctuations of ethylene and SO2 during the entire LVCC sampling process were proved to be samples were achieved in range of 95.0-101% and 97.0-104% respectively. It is expected that portable LVCC sampling technique would pave the way for rapid on-site analysis of accurate concentrations of trace gas targets from real samples by SERS.

  19. Technique and equipment for measuring volume activity of radon in the air of radon laboratories and clinics

    International Nuclear Information System (INIS)

    Vorob'ev, I.B.; Krivokhatskij, A.S.; Nekrasov, E.V.; Nikolaev, V.A.; Potapov, V.G.; Terent'ev, M.V.

    1990-01-01

    Usability of a new equipment-technique combination for measuring radon activity in the air of radon laboratories and balneological clinics is studied. The complex includes nitrate-cellulose detector, radon chamber, Aist, Istra type spark counters and technique of spark counting. The method sensitivity is 50 Bqxm 3 , the error is 30%. Usability and advisability of track method in radon laboratories and balneological clinics for simultaneous measurement in several points of integral volumetric radon activities are confirmred. The method permits to carry out rapid and accurate bulk investigations. The results of determining mean volumetric radon activity in the air in different points of radon laboratory and radon clinics are presented

  20. A novel iterative energy calibration method for composite germanium detectors

    International Nuclear Information System (INIS)

    Pattabiraman, N.S.; Chintalapudi, S.N.; Ghugre, S.S.

    2004-01-01

    An automatic method for energy calibration of the observed experimental spectrum has been developed. The method presented is based on an iterative algorithm and presents an efficient way to perform energy calibrations after establishing the weights of the calibration data. An application of this novel technique for data acquired using composite detectors in an in-beam γ-ray spectroscopy experiment is presented

  1. A novel iterative energy calibration method for composite germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pattabiraman, N.S.; Chintalapudi, S.N.; Ghugre, S.S. E-mail: ssg@alpha.iuc.res.in

    2004-07-01

    An automatic method for energy calibration of the observed experimental spectrum has been developed. The method presented is based on an iterative algorithm and presents an efficient way to perform energy calibrations after establishing the weights of the calibration data. An application of this novel technique for data acquired using composite detectors in an in-beam {gamma}-ray spectroscopy experiment is presented.

  2. Ridge augmentation with soft tissue procedures in aesthetic dentistry: pre- and postoperative volume measurements with a new kind of moire technique

    Science.gov (United States)

    Studer, Stephan P.; Mueller, Ernst; Bucher, Alfred

    1993-09-01

    The aim of this paper was to measure the volume differences of operated alveolar ridge defects before and until 3 months post-surgically. Ten patients with ten localized alveolar ridge defects were operated on. Five alveolar ridge defects were corrected by using the full thickness onlay graft technique and the other five defects were operated by the subepithelial connective tissue graft technique. A strict standardized operation protocol was followed and all alveolar ridge defects were operated on by the same dental surgeon. Before as well as 1, 2, and 3 months after surgery the corrected defect was photographed and an impression was made by using an A-silicon material to produce a gypsum-cast model. The form of all these cast models was then measured using the moire technique. The three months result of ten cases shows that the form of the operated alveolar ridge defects, which were corrected by the subepithelial connective tissue graft technique are more stable compared to those which were operated on by the full thickness onlay graft technique. Localized alveolar ridge defects using the latter method does not show a form stability after 3 months post-surgically.

  3. Soft Asphalt and Double Otta Seal—Self-Healing Sustainable Techniques for Low-Volume Gravel Road Rehabilitation

    Directory of Open Access Journals (Sweden)

    Audrius Vaitkus

    2018-01-01

    Full Text Available Increased traffic flow on low-volume gravel roads and deficiencies of national road infrastructure, are increasingly apparent in Lithuania. Gravel roads do not comply with requirements, resulting in low driving comfort, longer travelling time, faster vehicle amortization, and dustiness. The control of dustiness is one of the most important road maintenance activities on gravel roads. Another important issue is the assurance of required driving comfort and safety. Soft asphalt and Otta Seal technologies were proposed as a sustainable solution for the improvement of low-volume roads in Lithuania. Five gravel roads were constructed with soft asphalt, and 13 gravel roads were sealed with double Otta Seal, in 2012. The main aim of this research was to check soft asphalt and double Otta Seal’s ability to self-heal, on the basis of the results of the qualitative visual assessment of pavement defects and distress. The qualitative visual assessment was carried out twice a year following the opening of the rehabilitated road sections. The results confirmed soft asphalt and double Otta Seal’s ability to self-heal. The healing effect was more than 13% and 19% on roads with soft asphalt and double Otta Seal, respectively. In addition, on some roads, all cracks observed in spring self-healed during summer.

  4. First Industrial Tests of a Drum Monitor Matrix Correction for the Fissile Mass Measurement in Large Volume Historic Metallic Residues with the Differential Die-away Technique

    Energy Technology Data Exchange (ETDEWEB)

    Antoni, R.; Passard, C.; Perot, B.; Batifol, M.; Vandamme, J.C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 St Paul-lez-Durance, (France); Grassi, G. [AREVA NC, 1 place Jean-Millier, 92084 Paris-La-Defense cedex (France)

    2015-07-01

    The fissile mass in radioactive waste drums filled with compacted metallic residues (spent fuel hulls and nozzles) produced at AREVA La Hague reprocessing plant is measured by neutron interrogation with the Differential Die-away measurement Technique (DDT. In the next years, old hulls and nozzles mixed with Ion-Exchange Resins will be measured. The ion-exchange resins increase neutron moderation in the matrix, compared to the waste measured in the current process. In this context, the Nuclear Measurement Laboratory (NML) of CEA Cadarache has studied a matrix effect correction method, based on a drum monitor ({sup 3}He proportional counter inside the measurement cavity). A previous study performed with the NML R and D measurement cell PROMETHEE 6 has shown the feasibility of method, and the capability of MCNP simulations to correctly reproduce experimental data and to assess the performances of the proposed correction. A next step of the study has focused on the performance assessment of the method on the industrial station using numerical simulation. A correlation between the prompt calibration coefficient of the {sup 239}Pu signal and the drum monitor signal was established using the MCNPX computer code and a fractional factorial experimental design composed of matrix parameters representative of the variation range of historical waste. Calculations have showed that the method allows the assay of the fissile mass with an uncertainty within a factor of 2, while the matrix effect without correction ranges on 2 decades. In this paper, we present and discuss the first experimental tests on the industrial ACC measurement system. A calculation vs. experiment benchmark has been achieved by performing dedicated calibration measurement with a representative drum and {sup 235}U samples. The preliminary comparison between calculation and experiment shows a satisfactory agreement for the drum monitor. The final objective of this work is to confirm the reliability of the

  5. First Industrial Tests of a Drum Monitor Matrix Correction for the Fissile Mass Measurement in Large Volume Historic Metallic Residues with the Differential Die-away Technique

    International Nuclear Information System (INIS)

    Antoni, R.; Passard, C.; Perot, B.; Batifol, M.; Vandamme, J.C.; Grassi, G.

    2015-01-01

    The fissile mass in radioactive waste drums filled with compacted metallic residues (spent fuel hulls and nozzles) produced at AREVA La Hague reprocessing plant is measured by neutron interrogation with the Differential Die-away measurement Technique (DDT. In the next years, old hulls and nozzles mixed with Ion-Exchange Resins will be measured. The ion-exchange resins increase neutron moderation in the matrix, compared to the waste measured in the current process. In this context, the Nuclear Measurement Laboratory (NML) of CEA Cadarache has studied a matrix effect correction method, based on a drum monitor ( 3 He proportional counter inside the measurement cavity). A previous study performed with the NML R and D measurement cell PROMETHEE 6 has shown the feasibility of method, and the capability of MCNP simulations to correctly reproduce experimental data and to assess the performances of the proposed correction. A next step of the study has focused on the performance assessment of the method on the industrial station using numerical simulation. A correlation between the prompt calibration coefficient of the 239 Pu signal and the drum monitor signal was established using the MCNPX computer code and a fractional factorial experimental design composed of matrix parameters representative of the variation range of historical waste. Calculations have showed that the method allows the assay of the fissile mass with an uncertainty within a factor of 2, while the matrix effect without correction ranges on 2 decades. In this paper, we present and discuss the first experimental tests on the industrial ACC measurement system. A calculation vs. experiment benchmark has been achieved by performing dedicated calibration measurement with a representative drum and 235 U samples. The preliminary comparison between calculation and experiment shows a satisfactory agreement for the drum monitor. The final objective of this work is to confirm the reliability of the modeling approach

  6. Satellite imager calibration and validation

    CSIR Research Space (South Africa)

    Vhengani, L

    2010-10-01

    Full Text Available and Validation Lufuno Vhengani*, Minette Lubbe, Derek Griffith and Meena Lysko Council for Scientific and Industrial Research, Defence Peace Safety and Security, Pretoria, South Africa E-mail: * lvhengani@csir.co.za Abstract: The success or failure... techniques specific to South Africa. 1. Introduction The success or failure of any earth observation mission depends on the quality of its data. To achieve optimum levels of reliability most sensors are calibrated pre-launch. However...

  7. 18F-fluorocholine PET-guided target volume delineation techniques for partial prostate re-irradiation in local recurrent prostate cancer

    International Nuclear Information System (INIS)

    Wang Hui; Vees, Hansjoerg; Miralbell, Raymond; Wissmeyer, Michael; Steiner, Charles; Ratib, Osman; Senthamizhchelvan, Srinivasan; Zaidi, Habib

    2009-01-01

    Background and purpose: We evaluate the contribution of 18 F-choline PET/CT in the delineation of gross tumour volume (GTV) in local recurrent prostate cancer after initial irradiation using various PET image segmentation techniques. Materials and methods: Seventeen patients with local-only recurrent prostate cancer (median = 5.7 years) after initial irradiation were included in the study. Rebiopsies were performed in 10 patients that confirmed the local recurrence. Following injection of 300 MBq of 18 F-fluorocholine, dynamic PET frames (3 min each) were reconstructed from the list-mode acquisition. Five PET image segmentation techniques were used to delineate the 18 F-choline-based GTVs. These included manual delineation of contours (GTV man ) by two teams consisting of a radiation oncologist and a nuclear medicine physician each, a fixed threshold of 40% and 50% of the maximum signal intensity (GTV 40% and GTV 50% ), signal-to-background ratio-based adaptive thresholding (GTV SBR ), and a region growing (GTV RG ) algorithm. Geographic mismatches between the GTVs were also assessed using overlap analysis. Results: Inter-observer variability for manual delineation of GTVs was high but not statistically significant (p = 0.459). In addition, the volumes and shapes of GTVs delineated using semi-automated techniques were significantly higher than those of GTVs defined manually. Conclusions: Semi-automated segmentation techniques for 18 F-choline PET-guided GTV delineation resulted in substantially higher GTVs compared to manual delineation and might replace the latter for determination of recurrent prostate cancer for partial prostate re-irradiation. The selection of the most appropriate segmentation algorithm still needs to be determined.

  8. 18F-fluorocholine PET-guided target volume delineation techniques for partial prostate re-irradiation in local recurrent prostate cancer.

    Science.gov (United States)

    Wang, Hui; Vees, Hansjörg; Miralbell, Raymond; Wissmeyer, Michael; Steiner, Charles; Ratib, Osman; Senthamizhchelvan, Srinivasan; Zaidi, Habib

    2009-11-01

    We evaluate the contribution of (18)F-choline PET/CT in the delineation of gross tumour volume (GTV) in local recurrent prostate cancer after initial irradiation using various PET image segmentation techniques. Seventeen patients with local-only recurrent prostate cancer (median=5.7 years) after initial irradiation were included in the study. Rebiopsies were performed in 10 patients that confirmed the local recurrence. Following injection of 300 MBq of (18)F-fluorocholine, dynamic PET frames (3 min each) were reconstructed from the list-mode acquisition. Five PET image segmentation techniques were used to delineate the (18)F-choline-based GTVs. These included manual delineation of contours (GTV(man)) by two teams consisting of a radiation oncologist and a nuclear medicine physician each, a fixed threshold of 40% and 50% of the maximum signal intensity (GTV(40%) and GTV(50%)), signal-to-background ratio-based adaptive thresholding (GTV(SBR)), and a region growing (GTV(RG)) algorithm. Geographic mismatches between the GTVs were also assessed using overlap analysis. Inter-observer variability for manual delineation of GTVs was high but not statistically significant (p=0.459). In addition, the volumes and shapes of GTVs delineated using semi-automated techniques were significantly higher than those of GTVs defined manually. Semi-automated segmentation techniques for (18)F-choline PET-guided GTV delineation resulted in substantially higher GTVs compared to manual delineation and might replace the latter for determination of recurrent prostate cancer for partial prostate re-irradiation. The selection of the most appropriate segmentation algorithm still needs to be determined.

  9. Generalization techniques to reduce the number of volume elements for terrain effect calculations in fully analytical gravitational modelling

    Science.gov (United States)

    Benedek, Judit; Papp, Gábor; Kalmár, János

    2018-04-01

    Beyond rectangular prism polyhedron, as a discrete volume element, can also be used to model the density distribution inside 3D geological structures. The calculation of the closed formulae given for the gravitational potential and its higher-order derivatives, however, needs twice more runtime than that of the rectangular prism computations. Although the more detailed the better principle is generally accepted it is basically true only for errorless data. As soon as errors are present any forward gravitational calculation from the model is only a possible realization of the true force field on the significance level determined by the errors. So if one really considers the reliability of input data used in the calculations then sometimes the "less" can be equivalent to the "more" in statistical sense. As a consequence the processing time of the related complex formulae can be significantly reduced by the optimization of the number of volume elements based on the accuracy estimates of the input data. New algorithms are proposed to minimize the number of model elements defined both in local and in global coordinate systems. Common gravity field modelling programs generate optimized models for every computation points ( dynamic approach), whereas the static approach provides only one optimized model for all. Based on the static approach two different algorithms were developed. The grid-based algorithm starts with the maximum resolution polyhedral model defined by 3-3 points of each grid cell and generates a new polyhedral surface defined by points selected from the grid. The other algorithm is more general; it works also for irregularly distributed data (scattered points) connected by triangulation. Beyond the description of the optimization schemes some applications of these algorithms in regional and local gravity field modelling are presented too. The efficiency of the static approaches may provide even more than 90% reduction in computation time in favourable

  10. Development of optimized techniques and requirements for computer enhancement of structural weld radiographs. Volume 1: Technical report

    Science.gov (United States)

    Adams, J. R.; Hawley, S. W.; Peterson, G. R.; Salinger, S. S.; Workman, R. A.

    1971-01-01

    A hardware and software specification covering requirements for the computer enhancement of structural weld radiographs was considered. Three scanning systems were used to digitize more than 15 weld radiographs. The performance of these systems was evaluated by determining modulation transfer functions and noise characteristics. Enhancement techniques were developed and applied to the digitized radiographs. The scanning parameters of spot size and spacing and film density were studied to optimize the information content of the digital representation of the image.

  11. A dose-volume comparison of prostate cancer (PC) radiotherapy (RT) techniques for penile-structures (PNS) - a neglected critical organ in PC RT

    International Nuclear Information System (INIS)

    Dabrowski, Jolanta; Myrianthopoulos, Leon; Nguyen, Ai; Chen, George; Vijayakumar, Srinivasan

    1996-01-01

    Purpose/Objective: Three-dimensional conformal RT(3DCRT) is revolutionizing the use of RT in PC. Rectum and bladder, and in some studies femoral heads are included as critical structures (CS) in comparing rival plans in 3DCRT. Although RT-induced impotence is a major complication of conventional RT, with 30-50% incidence, to date no study has included PNS as a CS. This study is an attempt to remedy this deficiency in the 3DCRT planning in PC. Materials and Methods: After immobilization with Aquaplast, computed-tomography (CT) scans were obtained in supine treatment position from top of lumbar-3 vertebra to lesser-trochanter of the femora with 5-8mm slice-thicknesses; IV contrast was used in all patients. Prostate, seminal vesicles (GTV), and CSs were outlined, including PNS. Corpora cavernosa and bulbous spongiosum together were identified as PNS. Appropriate margins for CTV and PTV were used; total margin to the block from GTV was 2cm. Tumor-minimum doses were prescribed to the 100% isodose line. Dose-volume histograms (DVHs) were obtained to compare three different techniques: 1. Conventional 4 field box technique (4FC) with equal weighting; 2. Six field (2 laterals and 4 obliques [45 degrees from midline] (6FO), with 50% dose delivery from the laterals; and 3. Four equally weighted, non-axial fields [2 laterals and 2 inferior anterior obliques at 45 degree couch and gantry rotations] (4FN). Results: A total of 12 patients are included in the study. The mean and range of percentage volume of PNS receiving more than 30, 60, and 90% of the prescribed dose are shown in the table below: Box plots, such as the example shown above, were used to compare techniques overall. The 6-field coplanar technique treated the least PNS volume beyond a given dose, followed by 4FC and 4FN techniques. The order of least to maximum percent of PNS treated in most individual patients also followed the same trend. In the majority, 6FO and 4FN delivered relatively comparable doses to

  12. Anatomic and mechanical considerations in restoring volume of the face with use of hyaluronic acid fillers with a novel layered technique

    Directory of Open Access Journals (Sweden)

    Mohan K Thomas

    2014-01-01

    Full Text Available Context: Facial fillers have revolutionized the field of cosmetic facial rejuvenation as it has become the prime sought - after rejuvenation procedure offering youthful, 3-dimensional look with minimal invasiveness. Fillers are expensive and need to be redone periodically hence a sound understanding of structural basis on which they are laid is important in reducing the quantity of filler required in each sitting as well as increasing the longevity of results. Aim: The aim of the following study is to analyse a novel method of facial filling "The pillars pyramids and tie beams (PPT" technique and its advantages over the conventional methods. Subjects and Methods: A novel technique of injecting the facial fillers was employed on 67 patients visiting our clinic. These patients were followed-up for a period of 3 years. Results: We observed that the amount of filler material required in initial sitting remains the same, however the frequency of touch up visits is decreased and so is the amount of filler material required for follow-up injections. Conclusion: Facial contour remodelling is being revolutionised by the new filler materials for volume augmentation and no uniform consensus has been reached on the techniques currently used in clinical practice. We advocate this novel PPT technique of facial filling in facial rejuvenation to restore a youthful look as a primary goal.

  13. Anatomic and mechanical considerations in restoring volume of the face with use of hyaluronic acid fillers with a novel layered technique.

    Science.gov (United States)

    Thomas, Mohan K; Dsilva, James A; Borole, Ateesh J; Naik, Sudhir M; Sarkar, Soma G

    2014-01-01

    Facial fillers have revolutionized the field of cosmetic facial rejuvenation as it has become the prime sought - after rejuvenation procedure offering youthful, 3-dimensional look with minimal invasiveness. Fillers are expensive and need to be redone periodically hence a sound understanding of structural basis on which they are laid is important in reducing the quantity of filler required in each sitting as well as increasing the longevity of results. The aim of the following study is to analyse a novel method of facial filling "The pillars pyramids and tie beams (PPT)" technique and its advantages over the conventional methods. A novel technique of injecting the facial fillers was employed on 67 patients visiting our clinic. These patients were followed-up for a period of 3 years. We observed that the amount of filler material required in initial sitting remains the same, however the frequency of touch up visits is decreased and so is the amount of filler material required for follow-up injections. Facial contour remodelling is being revolutionised by the new filler materials for volume augmentation and no uniform consensus has been reached on the techniques currently used in clinical practice. We advocate this novel PPT technique of facial filling in facial rejuvenation to restore a youthful look as a primary goal.

  14. Does the IMRT technique allow improvement of treatment plans (e.g. lung sparing) for lung cancer patients with small lung volume: a planning study

    International Nuclear Information System (INIS)

    Komosinska, K.; Kepka, L.; Gizynska, M.; Zawadzka, A.

    2008-01-01

    Aim: We evaluated whether intensity-modulated radiation therapy (IMRT) may offer any advantages in comparison with three-dimensional conformal radiotherapy (3D-CRT) for patients with small lung volume (SLV). Methods: Treatment planning was performed for 10 NSCLC patients with the smallest lung volume (mean: 2241 cc) among 200 patients from our database. For each patient 3D-CRT and IMRT plans were prepared. The goal was to deliver 66 Gy/33 fractions, with dose constraints: mean lung dose (MLD) < 20 Gy, V20 < 35%; spinal cord - Dmax < 45 Gy. When the plan could not meet these criteria, total dose was reduced. The 3D-CRT and IMRT plans were compared. We investigated: prescribed dose, coverage and conformity indices, MLD, V5-V65 in the lung. Results: In 4 out of 10 plans, 3D-CRT did not allow 66 Gy to be delivered, because of predicted pulmonary toxicity. These 4 cases included 3 for which we did not reach 66 Gy with IMRT; still, for these 3 plans the total dose was increased by an average of 9 Gy with IMRT in comparison with 3D-CRT. Coverage indices were similar for both techniques. Conformity indices were better for IMRT plans. MLD was lower in five IMRT and two 3D-CRT plans if equal doses were delivered. The decrease in MLD was seen for cases with large PTV and high PTV/lung volume ratio. Lung V5 was lower for all 3D-CRT plans, 47% vs. 57% for IMRT; V15 and above were larger for 3D-CRT Conclusion: In the planning study, IMRT seems to be a promising technique for cases with SLV, especially when associated with large PT V. (authors)

  15. TECHNIQUE OF ESTIMATION OF ERROR IN THE REFERENCE VALUE OF THE DOSE DURING THE LINEAR ACCELERATOR RADIATION OUTPUT CALIBRATION PROCEDURE. Part 2. Dependence on the characteristics of collimator, optical sourse-distance indicator, treatment field, lasers and treatment couch

    Directory of Open Access Journals (Sweden)

    Y. V. Tsitovich

    2016-01-01

    Full Text Available To ensure the safety of radiation oncology patients needed to provide consistent functional characteristics of the medical linear accelerators, which affect the accuracy of dose delivery. To this end, their quality control procedures, which include the calibration of radiation output of the linac, the error in determining the dose reference value during which must not exceed 2 %, is provided. The aim is to develop a methodology for determining the error (difference between a measured value of quantity and its true value in determining this value, depending on the characteristics of the collimator, the source to surface distance pointer, lasers, radiation field and treatment table. To achieve the objectives have been carried out dosimetric measurements of Trilogy S/N 3567 linac dose distributions, on the basis of which dose errors depending on the accuracy setting the zero position of the collimator, the deviation of the collimator rotation isocenter, the sourcesurface distance pointer accuracy, field size accuracy, the accuracy of lasers and treatment table positioning were obtained. It was found that the greatest impact on the value of the error has the error in the optical SSD indication and the error in the lasers position in the plane perpendicular to the plane of incidence of the radiation beam (up to 3.64 % for the energy of 6 MV. Dose errors caused by error in the field size were different for two photon energies, and reached 2.54 % for 6 MeV and 1.33% for 18 MeV. Errors caused by the rest of the characteristic do not exceed 1 %. Thus, it is possible to express the results of periodic quality control of these devices integrated in linac in terms of dose and use them to conduct a comprehensive assessment of the possibility of clinical use of a linear accelerator for oncology patients irradiation on the basis of the calibration of radiation output in case of development of techniques that allow to analyze the influence dosimetric

  16. On-line monitoring for calibration reduction

    International Nuclear Information System (INIS)

    Hoffmann, M.

    2005-09-01

    On-Line Monitoring evaluates instrument channel performance by assessing its consistency with other plant indications. Elimination or reduction of unnecessary field calibrations can reduce associated labour costs, reduce personnel radiation exposure, and reduce the potential for calibration errors. On-line calibration monitoring is an important technique to implement a state-based maintenance approach and reduce unnecessary field calibrations. In this report we will look at how the concept is currently applied in the industry and what the arising needs are as it becomes more commonplace. We will also look at the PEANO System, a tool developed by the Halden Project to perform signal validation and on-line calibration monitoring. Some issues will be identified that are being addressed in the further development of these tools to better serve the future needs of the industry in this area. An outline for how to improve these points and which aspects should be taken into account is described in detail. (Author)

  17. Impact of the radiotherapy technique on the correlation between dose–volume histograms of the bladder wall defined on MRI imaging and dose–volume/surface histograms in prostate cancer patients

    International Nuclear Information System (INIS)

    Maggio, Angelo; Carillo, Viviana; Perna, Lucia; Fiorino, Claudio; Cozzarini, Cesare; Rancati, Tiziana; Valdagni, Riccardo; Gabriele, Pietro

    2013-01-01

    The aim of this study was to evaluate the correlation between the ‘true’ absolute and relative dose–volume histograms (DVHs) of the bladder wall, dose–wall histogram (DWH) defined on MRI imaging and other surrogates of bladder dosimetry in prostate cancer patients, planned both with 3D-conformal and intensity-modulated radiation therapy (IMRT) techniques. For 17 prostate cancer patients, previously treated with radical intent, CT and MRI scans were acquired and matched. The contours of bladder walls were drawn by using MRI images. External bladder surfaces were then used to generate artificial bladder walls by performing automatic contractions of 5, 7 and 10 mm. For each patient a 3D conformal radiotherapy (3DCRT) and an IMRT treatment plan was generated with a prescription dose of 77.4 Gy (1.8 Gy/fr) and DVH of the whole bladder of the artificial walls (DVH-5/10) and dose–surface histograms (DSHs) were calculated and compared against the DWH in absolute and relative value, for both treatment planning techniques. A specific software (VODCA v. 4.4.0, MSS Inc.) was used for calculating the dose–volume/surface histogram. Correlation was quantified for selected dose–volume/surface parameters by the Spearman correlation coefficient. The agreement between %DWH and DVH5, DVH7 and DVH10 was found to be very good (maximum average deviations below 2%, SD < 5%): DVH5 showed the best agreement. The correlation was slightly better for absolute (R = 0.80–0.94) compared to relative (R = 0.66–0.92) histograms. The DSH was also found to be highly correlated with the DWH, although slightly higher deviations were generally found. The DVH was not a good surrogate of the DWH (R < 0.7 for most of parameters). When comparing the two treatment techniques, more pronounced differences between relative histograms were seen for IMRT with respect to 3DCRT (p < 0.0001). (note)

  18. Review of current research into soil decontamination and volume reduction techniques for purposes of transportation and disposal

    International Nuclear Information System (INIS)

    Haywood, F.F.

    1986-01-01

    In recent years, a number of soil decontamination studies have been carried out by investigators in the US and Canada. These investigations have included the segregation of potentially hazardous chemicals from uranium mill tailings, the use of various leaching agents for the selective removal of radium, thorium, and uranium from mine and mill tailings, the study of neutralization, fixation, and conditioning processes for tailings, the separation and removal of transuranium elements from contaminated soil and sediment, and finally studies of the cost effectiveness of various decontamination approaches. Remedial action programs for which soil decontamination may be an attractive alternative are those which include the cleanup of large open land areas since thousands of cubic years of material are generally involved. The practice of decontaminating or otherwise segregating contaminated and uncontaminated soil fractions before shipment to a final disposal site can only be done if it is economical to do so. This paper considers several techniques which have been reported in unclassified literature and includes a comparison of the authors' conclusions regarding the effectiveness of their investigations. The manuscript will include a comprehensive bibliography of references to techniques which appear to be feasible alternatives in remedial action programs

  19. Comparison of different calibration methods suited for calibration problems with many variables

    DEFF Research Database (Denmark)

    Holst, Helle

    1992-01-01

    This paper describes and compares different kinds of statistical methods proposed in the literature as suited for solving calibration problems with many variables. These are: principal component regression, partial least-squares, and ridge regression. The statistical techniques themselves do...

  20. Calibration of Flick standards

    International Nuclear Information System (INIS)

    Thalmann, Ruedi; Spiller, Jürg; Küng, Alain; Jusko, Otto

    2012-01-01

    Flick standards or magnification standards are widely used for an efficient and functional calibration of the sensitivity of form measuring instruments. The results of a recent measurement comparison have shown to be partially unsatisfactory and revealed problems related to the calibration of these standards. In this paper the influence factors for the calibration of Flick standards using roundness measurement instruments are discussed in detail, in particular the bandwidth of the measurement chain, residual form errors of the device under test, profile distortions due to the diameter of the probing element and questions related to the definition of the measurand. The different contributions are estimated using simulations and are experimentally verified. Also alternative methods to calibrate Flick standards are investigated. Finally the practical limitations of Flick standard calibration are shown and the usability of Flick standards both to calibrate the sensitivity of roundness instruments and to check the filter function of such instruments is analysed. (paper)

  1. Calibration of optical cantilever deflection readers

    International Nuclear Information System (INIS)

    Hu Zhiyu; Seeley, Tim; Kossek, Sebastian; Thundat, Thomas

    2004-01-01

    Because of its ultrahigh sensitivity, the optical lever detection method similar to that used in the atomic force microscope (AFM) has been widely employed as a standard technique for measuring microcantilever deflection. Along with the increasing interest in using the microcantilever as a sensing platform, there is also a requirement for a reliable calibration technique. Many researchers have used the concept of optical lever detection to construct microcantilever deflection readout instruments for chemical, physical, and biological detection. However, without an AFM piezo z scanner, it is very difficult to precisely calibrate these instruments. Here, we present a step-by-step method to conveniently calibrate an instrument using commercially available piezoresistive cantilevers. The experimental results closely match the theoretical calculation. Following this procedure, one can easily calibrate any optical cantilever deflection detection system with high reproducibility, precision, and reliability. A detailed discussion of the optical lever readout system design has been addressed in this article

  2. Calibration of NRSF2 Instrument at HFIR

    International Nuclear Information System (INIS)

    Tang, Fei; Hubbard, Camden R.

    2006-01-01

    The Neutron Residual Stress Mapping Facility (NRSF2) at HB-2B is a new generation-diffraction instrument, adding many new Second Generation features, such as larger beam tube, large sample XYZ goniometer, and KAPPA orienter for a broad range of materials behavior studies. One key feature is the NRSF2 monochromator, which is a double focusing, double crystal monochromator system consisting of two sets of stacked Si crystal wafers. One set of wafers has Si[400] plane normal to the surface while the other set of wafers has the Si[500] normal to the surface. The monochromator crystal diffracts at a fixed diffraction angle of 88 o selecting a neutron wavelength determined by the monochromator d hkl -spacing. This 'Missouri' monochromator system has two independent monochromators, which enable diffraction from the following set of six diffraction planes: Si(511), Si(422), Si(331)AF (Anti-Fankuchen geometry), Si(400), Si(311), and Si(220). These diffraction planes can provide 6 different neutron wavelengths: approximately 1.45, 1.54, 1.73, 1.89 (angstrom), 2.27, and 2.66 also incorporate seven position sensitive detectors located in a detector shield box. To use this advanced instrument for scientific and engineering measurements, careful calibration needs to be performed to accurately calibrate the seven position sensitive detectors, neutron wavelength, and 2θ 0 . Just as in the X-ray diffraction technique, neutron diffraction directly measures the diffraction angle (2θ) or diffraction peak position, then based on Bragg's law and a strain free lattice spacing, the strain can be calculated. Therefore anything that can affect the diffracting angle measurement can influence the accuracy of the strain measurements. The sources of difficulties in achieving accurate neutron diffraction peak positions can be classified into three categories. (1) Instrument - These difficulties come from alignment of the monochromator, alignment of the incident and detector slits, leveling of

  3. Nuclear power plant personnel qualifications and training. TSORT: an automated technique to assign tasks to training strategies. Volume 1

    International Nuclear Information System (INIS)

    Jorgensen, C.C.

    1984-10-01

    This report discusses TSORT, a technique to assist the Nuclear Regulatory Commission (NRC) in evaluating whether training program developers have allocated nuclear power plant tasks to appropriate training strategies. The TSORT structure is presented including training categories selected, dimensions of task information considered, measurement metrics used, and a guide to application. TSORT is implemented as an automated software tool for an IBM-PC. It uses full color graphics and interactive menu selection to provide NRC with a variety of evaluation options including: rank ordering of training strategies reasonable for each task, rank ordering of tasks within strategies, and a variety of special analyses. The program code is also presented along with a comprehensive example of 20 realistic tasks illustrating each of 17 options available

  4. Providing primary standard calibrations beyond 20 MHz

    International Nuclear Information System (INIS)

    Bickley, C J; Zeqiri, B; Robinson, S P

    2004-01-01

    The number of applications of medical ultrasound utilising frequencies in excess of 20 MHz has shown a consistent increase over recent years. Coupled with the commercial availability of wide-bandwidth hydrophones whose response extends beyond 40 MHz, this has driven a growing need to develop hydrophone calibration techniques at elevated frequencies. The current National Physical Laboratory primary standard method of calibrating hydrophones is based on an optical interferometer. This has been in operation for around 20 years and provides traceability over the frequency range of 0.3 to 20 MHz. More recently, calibrations carried out using the interferometer have been extended to 60 MHz, although the uncertainties associated with these calibrations are poor, being in excess of ±20% at high frequencies. Major contributions to the degraded calibration uncertainties arise from poor signal-to-noise at higher frequencies, the frequency response of the photodiodes used and the noise floor of the instrument. To improve the uncertainty of hydrophone calibrations above 20 MHz, it has been necessary to build and commission a new interferometer. Important features of the new primary standard are its use of a higher power laser to improve the signal-to-noise ratio, along with photodiodes whose greater bandwidth to improve the overall frequency response. This paper describes the design of key aspects of the new interferometer. It also presents some initial results of the performance assessment, including a detailed comparison of calibrations of NPL reference membrane hydrophones, undertaken using old and new interferometers for calibration up to 40 MHz

  5. Error-in-variables models in calibration

    Science.gov (United States)

    Lira, I.; Grientschnig, D.

    2017-12-01

    In many calibration operations, the stimuli applied to the measuring system or instrument under test are derived from measurement standards whose values may be considered to be perfectly known. In that case, it is assumed that calibration uncertainty arises solely from inexact measurement of the responses, from imperfect control of the calibration process and from the possible inaccuracy of the calibration model. However, the premise that the stimuli are completely known is never strictly fulfilled and in some instances it may be grossly inadequate. Then, error-in-variables (EIV) regression models have to be employed. In metrology, these models have been approached mostly from the frequentist perspective. In contrast, not much guidance is available on their Bayesian analysis. In this paper, we first present a brief summary of the conventional statistical techniques that have been developed to deal with EIV models in calibration. We then proceed to discuss the alternative Bayesian framework under some simplifying assumptions. Through a detailed example about the calibration of an instrument for measuring flow rates, we provide advice on how the user of the calibration function should employ the latter framework for inferring the stimulus acting on the calibrated device when, in use, a certain response is measured.

  6. Calibration Laboratory of the Paul Scherrer Institute

    International Nuclear Information System (INIS)

    Gmuer, K.; Wernli, C.

    1994-01-01

    Calibration and working checks of radiation protection instruments are carried out at the Calibration Laboratory of the Paul Scherrer Institute. In view of the new radiation protection regulation, the calibration laboratory received an official federal status. The accreditation procedure in cooperation with the Federal Office of Metrology enabled a critical review of the techniques and methods applied. Specifically, personal responsibilities, time intervals for recalibration of standard instruments, maximum permissible errors of verification, traceability and accuracy of the standard instruments, form and content of the certificates were defined, and the traceability of the standards and quality assurance were reconsidered. (orig.) [de

  7. Modeling Approach for Estimating Co-Produced Water Volumes and Saltwater Disposal Volumes in Oklahoma

    Science.gov (United States)

    Murray, K. E.

    2016-12-01

    Management of produced fluids has become an important issue in Oklahoma because large volumes of saltwater are co-produced with oil and gas, and disposed into saltwater disposal wells at high rates. Petroleum production increased from 2009-2015, especially in central and north-central Oklahoma where the Mississippian and Hunton zones were redeveloped using horizontal wells and dewatering techniques that have led to a disproportional increase in produced water volumes. Improved management of co-produced water, including desalination for beneficial reuse and decreased saltwater disposal volumes, is only possible if spatial and temporal trends can be defined and related to the producing zones. It is challenging to quantify the volumes of co-produced water by region or production zone because co-produced water volumes are generally not reported. Therefore, the goal of this research is to estimate co-produced water volumes for 2008-present with an approach that can be replicated as petroleum production shifts to other regions. Oil and gas production rates from subsurface zones were multiplied by ratios of H2O:oil and H2O:gas for the respective zones. Initial H2O:oil and H2O:gas ratios were adjusted/calibrated, by zone, to maximize correlation of county-scale produced H2O estimates versus saltwater disposal volumes from 2013-2015. These calibrated ratios were then used to compute saltwater disposal volumes from 2008-2012 because of apparent data gaps in reported saltwater disposal volumes during that timeframe. This research can be used to identify regions that have the greatest need for produced water treatment systems. The next step in management of produced fluids is to explore optimal energy-efficient strategies that reduce deleterious effects.

  8. Calibration curves for biological dosimetry

    International Nuclear Information System (INIS)

    Guerrero C, C.; Brena V, M. . E-mail cgc@nuclear.inin.mx

    2004-01-01

    The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)

  9. Examination of forensic entomology evidence using computed tomography scanning: case studies and refinement of techniques for estimating maggot mass volumes in bodies.

    Science.gov (United States)

    Johnson, Aidan; Archer, Melanie; Leigh-Shaw, Lyndie; Pais, Mike; O'Donnell, Chris; Wallman, James

    2012-09-01

    A new technique has recently been developed for estimating the volume of maggot masses on deceased persons using post-mortem CT scans. This allows volume to be measured non-invasively and factored into maggot mass temperature calculations for both casework and research. Examination of admission scans also allows exploration of entomological evidence in anatomical areas not usually exposed by autopsy (e.g. nasal cavities and facial sinuses), and before autopsy disrupts the maggot distribution on a body. This paper expands on work already completed by providing the x-ray attenuation coefficient by way of Hounsfield unit (HU) values for various maggot species, maggot masses and human tissue adjacent to masses. Specifically, this study looked at the HU values for four forensically important blowfly larvae: Lucilia cuprina, L. sericata, Calliphora stygia and C. vicina. The Calliphora species had significantly lower HU values than the Lucilia species. This might be explained by histological analysis, which revealed a non-significant trend, suggesting that Calliphora maggots have a higher fat content than the Lucilia maggots. It is apparent that the variation in the x-ray attenuation coefficient usually precludes its use as a tool for delineating the maggot mass from human tissue and that morphology is the dominant method for delineating a mass. This paper also includes three case studies, which reveal different applications for interpreting entomological evidence using post-mortem CT scans.

  10. Low contrast volume run-off CT angiography with optimized scan time based on double-level test bolus technique – feasibility study

    International Nuclear Information System (INIS)

    Baxa, Jan; Vendiš, Tomáš; Moláček, Jiří; Štěpánková, Lucie; Flohr, Thomas; Schmidt, Bernhard; Korporaal, Johannes G.; Ferda, Jiří

    2014-01-01

    Purpose: To verify the technical feasibility of low contrast volume (40 mL) run-off CT angiography (run-off CTA) with the individual scan time optimization based on double-level test bolus technique. Materials and methods: A prospective study of 92 consecutive patients who underwent run-off CTA performed with 40 mL of contrast medium (injection rate of 6 mL/s) and optimized scan times on a second generation of dual-source CT. Individual optimized scan times were calculated from aortopopliteal transit times obtained on the basis of double-level test bolus technique – the single injection of 10 mL test bolus and dynamic acquisitions in two levels (abdominal aorta and popliteal arteries). Intraluminal attenuation (HU) was measured in 6 levels (aorta, iliac, femoral and popliteal arteries, middle and distal lower-legs) and subjective quality (3-point score) was assessed. Relations of image quality, test bolus parameters and arterial circulation involvement were analyzed. Results: High mean attenuation (HU) values (468; 437; 442; 440; 342; 274) and quality score in all monitored levels was achieved. In 91 patients (0.99) the sufficient diagnostic quality (score 1–2) in aorta, iliac and femoral arteries was determined. A total of 6 patients (0.07) were not evaluable in distal lower-legs. Only the weak indirect correlation of image quality and test-bolus parameters was proved in iliac, femoral and popliteal levels (r values: −0.263, −0.298 and −0.254). The statistically significant difference of the test-bolus parameters and image quality was proved in patients with occlusive and aneurysmal disease. Conclusion: We proved the technical feasibility and sufficient quality of run-off CTA with low volume of contrast medium and optimized scan time according to aortopopliteal transit time calculated from double-level test bolus

  11. Establishment of an open database of realistic simulated data for evaluation of partial volume correction techniques in brain PET/MR

    Energy Technology Data Exchange (ETDEWEB)

    Mota, Ana [Instituto de Biofísica e Engenharia Biomédica, FC-UL, Lisboa (Portugal); Institute of Nuclear Medicine, UCL, London (United Kingdom); Cuplov, Vesna [Instituto de Biofísica e Engenharia Biomédica, FC-UL, Lisboa (Portugal); Schott, Jonathan; Hutton, Brian; Thielemans, Kris [Institute of Nuclear Medicine, UCL, London (United Kingdom); Drobnjak, Ivana [Centre of Medical Image Computing, UCL, London (United Kingdom); Dickson, John [Institute of Nuclear Medicine, UCL, London (United Kingdom); Bert, Julien [INSERM UMR1101, LaTIM, CHRU de Brest, Brest (France); Burgos, Ninon; Cardoso, Jorge; Modat, Marc; Ourselin, Sebastien [Centre of Medical Image Computing, UCL, London (United Kingdom); Erlandsson, Kjell [Institute of Nuclear Medicine, UCL, London (United Kingdom)

    2015-05-18

    The Partial Volume (PV) effect in Positron Emission Tomography (PET) imaging leads to loss in quantification accuracy, which manifests in PV effects (small objects occupy partially the sensitive volume of the imaging instrument, resulting in blurred images). Simultaneous acquisition of PET and Magnetic Resonance Imaging (MRI) produces concurrent metabolic and anatomical information. The latter has proved to be very helpful for the correction of PV effects. Currently, there are several techniques used for PV correction. They can be applied directly during the reconstruction process or as a post-processing step after image reconstruction. In order to evaluate the efficacy of the different PV correction techniques in brain- PET, we are constructing a database of simulated data. Here we present the framework and steps involved in constructing this database. Static 18F-FDG epilepsy and 18F-Florbetapir amyloid dementia PET/MR were selected because of their very different characteristics. The methodology followed was based on four main steps: Image pre-processing, Ground Truth (GT) generation, MRI and PET data simulation and reconstruction. All steps used Open Source software and can therefore be repeated at any centre. The framework as well as the database will be freely accessible. Tools used included GIF, FSL, POSSUM, GATE and STIR. The final data obtained after simulation, involving raw or reconstructed PET data together with corresponding MRI datasets, were close to the original patient data. Besides, there is the advantage that data can be compared with the GT. We indicate several parameters that can be improved and optimized.

  12. Establishment of an open database of realistic simulated data for evaluation of partial volume correction techniques in brain PET/MR

    International Nuclear Information System (INIS)

    Mota, Ana; Cuplov, Vesna; Schott, Jonathan; Hutton, Brian; Thielemans, Kris; Drobnjak, Ivana; Dickson, John; Bert, Julien; Burgos, Ninon; Cardoso, Jorge; Modat, Marc; Ourselin, Sebastien; Erlandsson, Kjell

    2015-01-01

    The Partial Volume (PV) effect in Positron Emission Tomography (PET) imaging leads to loss in quantification accuracy, which manifests in PV effects (small objects occupy partially the sensitive volume of the imaging instrument, resulting in blurred images). Simultaneous acquisition of PET and Magnetic Resonance Imaging (MRI) produces concurrent metabolic and anatomical information. The latter has proved to be very helpful for the correction of PV effects. Currently, there are several techniques used for PV correction. They can be applied directly during the reconstruction process or as a post-processing step after image reconstruction. In order to evaluate the efficacy of the different PV correction techniques in brain- PET, we are constructing a database of simulated data. Here we present the framework and steps involved in constructing this database. Static 18F-FDG epilepsy and 18F-Florbetapir amyloid dementia PET/MR were selected because of their very different characteristics. The methodology followed was based on four main steps: Image pre-processing, Ground Truth (GT) generation, MRI and PET data simulation and reconstruction. All steps used Open Source software and can therefore be repeated at any centre. The framework as well as the database will be freely accessible. Tools used included GIF, FSL, POSSUM, GATE and STIR. The final data obtained after simulation, involving raw or reconstructed PET data together with corresponding MRI datasets, were close to the original patient data. Besides, there is the advantage that data can be compared with the GT. We indicate several parameters that can be improved and optimized.

  13. Calibration of moisture monitors

    International Nuclear Information System (INIS)

    Gutierrez, R.L.

    1979-02-01

    A method for calibrating an aluminum oxide hygrometer against an optical chilled mirror dew-point hygrometer has been established. A theoretical cross-point line of dew points from both hygrometers and a maximum moisture content of 10 ppM/sub v/ are used to define an area for calibrating the sensor probes of the aluminum oxide hygrometer

  14. Site Calibration report

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Vesth, Allan

    The report describes site calibration measurements carried out on a site in Denmark. The measurements are carried out in accordance to Ref. [1]. The site calibration is carried out before a power performance measurement on a given turbine to clarify the influence from the terrain on the ratio...

  15. Topics in Statistical Calibration

    Science.gov (United States)

    2014-03-27

    Natural cubic spline speed di st 110 B.2 The calibrate function The most basic calibration problem, the one often encountered in more advanced ...0040-1706, 1537-2723. A. M. Mood, F. A. Graybill, and D. C. Boes. Introduction to the Theory of Statistics. McGraw-Hill, Auckland , U.A, 1974. ISBN

  16. Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

    International Nuclear Information System (INIS)

    Brau-Avila, A; Valenzuela-Galvan, M; Herrera-Jimenez, V M; Santolaria, J; Aguilar, J J; Acero, R

    2017-01-01

    The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs. (paper)

  17. Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

    Science.gov (United States)

    Brau-Avila, A.; Santolaria, J.; Acero, R.; Valenzuela-Galvan, M.; Herrera-Jimenez, V. M.; Aguilar, J. J.

    2017-03-01

    The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs.

  18. Sandia WIPP calibration traceability

    Energy Technology Data Exchange (ETDEWEB)

    Schuhen, M.D. [Sandia National Labs., Albuquerque, NM (United States); Dean, T.A. [RE/SPEC, Inc., Albuquerque, NM (United States)

    1996-05-01

    This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities.

  19. The GERDA calibration system

    Energy Technology Data Exchange (ETDEWEB)

    Baudis, Laura; Froborg, Francis; Tarka, Michael; Bruch, Tobias; Ferella, Alfredo [Physik-Institut, Universitaet Zuerich (Switzerland); Collaboration: GERDA-Collaboration

    2012-07-01

    A system with three identical custom made units is used for the energy calibration of the GERDA Ge diodes. To perform a calibration the {sup 228}Th sources are lowered from the parking positions at the top of the cryostat. Their positions are measured by two independent modules. One, the incremental encoder, counts the holes in the perforated steel band holding the sources, the other measures the drive shaft's angular position even if not powered. The system can be controlled remotely by a Labview program. The calibration data is analyzed by an iterative calibration algorithm determining the calibration functions for different energy reconstruction algorithms and the resolution of several peaks in the {sup 228}Th spectrum is determined. A Monte Carlo simulation using the GERDA simulation software MAGE has been performed to determine the background induced by the sources in the parking positions.

  20. Sandia WIPP calibration traceability

    International Nuclear Information System (INIS)

    Schuhen, M.D.; Dean, T.A.

    1996-05-01

    This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities

  1. Evaluating the effect of crumb rubber and nano silica on the properties of high volume fly ash roller compacted concrete pavement using non-destructive techniques

    Directory of Open Access Journals (Sweden)

    Bashar S. Mohammed

    2018-06-01

    Full Text Available The major problems related to roller compacted concrete (RCC pavement are high rigidity, lower tensile strength which causes a tendency of cracking due to thermal or plastic shrinkage, flexural and fatigue loads. Furthermore, RCC pavement does not support the use of dowel bars or reinforcement due to the way it is placed and compacted, these also aided in cracking and consequently increased maintenance cost. To address these issues, high volume fly ash (HVFA RCC pavement was developed by partially replacing 50% cement by volume with fly ash. Crumb rubber was used as a partial replacement to fine aggregate in HVFA RCC pavement at 0%, 10%, 20%, and 30% replacement by volume. Nano silica was added at 0%, 1%, 2% and 3% by weight of cementitious materials to improve early strength development in HVFA RCC pavement and mitigate the loss of strength due to the incorporation of crumb rubber. The nondestructive technique using the rebound hammer test (RHT and ultrasonic pulse velocity (UPV were used to evaluate the effect of crumb rubber and nano silica on the performance of HVFA RCC pavement. The results showed that the use of HVFA as cement replacement decreases both the unit weight, compressive strength, rebound number (RN. Furthermore, the unit weight, compressive strength, RN, UPV and dynamic modulus of elasticity of HVFA RCC pavement all decreases with increase in crumb rubber content and increases with the addition of nano-silica. Combined UPV-RN (SonReb models for predicting the 28 days strength of HVFA RCC pavement based on combining UPV and RN were developed using multivariable regression (double power, bilinear, and double exponential models. The exponential combined SonReb model is the most suitable for predicting the compressive strength of HVFA RCC pavement using UPV and RN as the independent variable with better predicting ability, higher correlation compared to the single variable models. Keywords: Crumb rubber, High volume fly ash, Nano

  2. Automated Energy Calibration and Fitting of LaCl3(Ce y-Spectra Using Peak Likelihood and Tabu Search

    Directory of Open Access Journals (Sweden)

    Timothy P. McClanahan

    2008-10-01

    Full Text Available An automated method for ?-emission spectrum calibration and deconvolution is presented for spaceflight applications for a Cerium doped Lanthanum Chloride, (LaCl3(Ce ?-ray detector system. This detector will be coupled with a pulsed neutron generator (PNG to induce and enhance nuclide signal quality and rates, yielding large volumes of spectral information. Automated analytical methods are required to deconvolve and quantify nuclide signals from spectra; this will both reduce human interactions in spectrum analysis and facilitate feedback to automated robotic and operations planning. Initial system tests indicate significant energy calibration drifts (>6%, that which must be mitigated for spectrum analysis. A linear energy calibration model is presently considered, with gain and zero factors. Deconvolution methods incorporate a tabu search heuristic to formulate and optimize searches using memory structures. Iterative use of a peak likelihood methodology identifies global calibration minima and peak areas. The method is compared to manual methods of calibration and indicates superior performance using tabu methods. Performance of the Tabu enhanced calibration method is superior to similar unoptimized local search. The techniques are also applicable to other emission spectroscopy, eg. X-ray and neutron.

  3. Contrast-enhanced MDCT gastrography for detection of early gastric cancer: Initial assessment of “wall-carving image”, a novel volume rendering technique

    International Nuclear Information System (INIS)

    Komori, Masahiro; Kawanami, Satoshi; Tsurumaru, Daisuke; Matsuura, Shuji; Hiraka, Kiyohisa; Nishie, Akihiro; Honda, Hiroshi

    2012-01-01

    Objective: We developed a new volume rendering technique, the CT gastrography wall carving image (WC) technique, which provides a clear visualization of localized enhanced tumors in the gastric wall. We evaluated the diagnostic performance of the WC as an adjunct to conventional images in detecting early gastric cancer (EGC). Materials and methods: Thirty-nine patients with 43 EGCs underwent contrast-enhanced MDCT gastrography for preoperative examination. Two observers independently reviewed the images under three different conditions: term 1, Axial CT; term 2, Axial CT, MPR and VE; and term 3, Axial CT, MPR, VE and WC for the detection of EGC. The accuracy of each condition as reviewed by each of the two observers was evaluated by receiver operating characteristic analysis. Interobserver agreement was calculated using weighted-κ statistics. Results: The best diagnostic performance and interobserver agreement were obtained in term 3. The AUCs of the two observers for terms 1, 2, and 3 were 0.63, 0.73, and 0.84, and 0.57, 0.73, and 0.76, respectively. The interobserver agreement improved from fair at term 1 to substantial at term 3. Conclusions: The addition of WC to conventional MDCT display improved the diagnostic accuracy and interobserver reproducibility for the detection of ECG. WC represents a suitable alternative for the visualization of localized enhanced tumors in the gastric wall.

  4. Contribution to the RMTC in the field of tank calibration and measurements - the TAMSCA laboratory

    International Nuclear Information System (INIS)

    Hunt, B.A.; Landat, D.; Caviglia, M.; Silvapestana, L.

    1999-01-01

    The Russian Methodological and Training Centre (RMTC) is being established for training of personnel from the various Russian and CIS nuclear facilities organizations in the control and accountancy methods, utilised in EURATOM and in the IAEA. Under the project equipment and support will be provided in a number of areas, namely containment and surveillance, training, passive/active neutron assay and mass/volume methodologies. For the latter a mass/volume measurement laboratory - a Tank Measurements and Calibration Laboratory (TAMSCA) is being set-up in IPPE, Obninsk. The goal is to upgrade the methodology within the Russian Federation in the application of mass/volume measurement techniques and render a facility suitable adapted to carrying out training courses with specific orientation for the nuclear inspectors and operators of nuclear facilities for nuclear accountancy and control [ru

  5. Proton beam monitor chamber calibration

    International Nuclear Information System (INIS)

    Gomà, C; Meer, D; Safai, S; Lorentini, S

    2014-01-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams. (paper)

  6. The value of three-dimensional photogrammetry in isolated sagittal synostosis: Impact of age and surgical technique on intracranial volume and cephalic index─a retrospective cohort study.

    Science.gov (United States)

    Mertens, Christian; Wessel, Eline; Berger, Moritz; Ristow, Oliver; Hoffmann, Jürgen; Kansy, Katinka; Freudlsperger, Christian; Bächli, Heidrun; Engel, Michael

    2017-12-01

    The aim of this study was to compare the outcome of intracranial volume (ICV) and cephalic index (CI) between two different techniques for surgical therapy of sagittal synostosis. Between 2011 and 2015, all patients scheduled for surgical therapy of sagittal synostosis were consecutively enrolled. All patients younger than 6 months underwent early extended strip craniectomy (ESC group), and patients older than 6 months underwent late modified pi-procedure (MPP group). To measure ICV and CI, data acquisition was performed via three-dimensional photogrammetry, 1 day before (T0) and between 10 and 12 weeks after surgery (T1). Results were compared with an age-matched reference group of healthy children. Perioperative parameters, as duration of surgery and the amount of blood loss of both surgical procedures were analyzed. A total of 85 patients were enrolled. Of the patients, 48 underwent an extended strip craniotomy with parietal osteotomies and biparietal widening and 37 patients underwent a late modified pi-procedure. There was no significant difference between the ESC group and the MPP group regarding the efficacy of improving CI (p > 0.05). Both techniques were able to normalize CI and to improve head shape. ICV was normal compared to age-matched norm-groups with both techniques, pre- and postoperatively. However, duration of the surgical procedure and calculated blood loss were significantly lower in the ESC group (p photogrammetry is a valid method to objectively evaluate patients before and after surgery without exposing pediatric patients to ionizing radiation. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  7. Calibration of the solar neutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Caccianiga, Barbara; Re, Alessandra Carlotta [Universita degli Studi Milano (Italy); INFN, Milano (Italy)

    2016-04-15

    Calibrations have been crucial for the success of solar neutrino experiments. In this contribution we review the calibration strategies adopted by different solar neutrino experiments. In particular, we will emphasize their common critical aspects and their main differences. In order to do so, we will schematically divide the solar neutrino experiments in two groups: those based on radiochemical techniques, i.e. Homestake, Gallex/GNO, SAGE and those based on real-time techniques i.e. Kamiokande, Super-Kamiokande, SNO, Borexino and KamLAND. (orig.)

  8. Lidar to lidar calibration

    DEFF Research Database (Denmark)

    Fernandez Garcia, Sergio; Villanueva, Héctor

    This report presents the result of the lidar to lidar calibration performed for ground-based lidar. Calibration is here understood as the establishment of a relation between the reference lidar wind speed measurements with measurement uncertainties provided by measurement standard and corresponding...... lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from the reference lidar measurements are given for information only....

  9. The 2007 ESO Instrument Calibration Workshop

    CERN Document Server

    Kaufer, Andreas; ESO Workshop

    2008-01-01

    The 2007 ESO Instrument Calibration workshop brought together more than 120 participants with the objective to a) foster the sharing of information, experience and techniques between observers, instrument developers and instrument operation teams, b) review the actual precision and limitations of the applied instrument calibration plans, and c) collect the current and future requirements by the ESO users. These present proceedings include the majority of the workshop’s contributions and document the status quo of instrument calibration at ESO in large detail. Topics covered are: Optical Spectro-Imagers, Optical Multi-Object Spectrographs, NIR and MIR Spectro-Imagers, High-Resolution Spectrographs, Integral Field Spectrographs, Adaptive Optics Instruments, Polarimetric Instruments, Wide Field Imagers, Interferometric Instruments as well as other crucial aspects such as data flow, quality control, data reduction software and atmospheric effects. It was stated in the workshop that "calibration is a life-long l...

  10. X-ray film calibration

    International Nuclear Information System (INIS)

    Stone, G.F.; Dittmore, C.H.; Henke, B.L.

    1986-01-01

    This paper discusses the use of silver halide x-ray films for imaging and spectroscopy which is limited by the range of intensities that can be recorded and densitometered. Using the manufacturers processing techniques can result in 10 2-3 range in intensity recorded over 0-5 density range. By modifying the chemistry and processing times, ranges of 10 5-6 can be recorded in the same density range. The authors report on x-ray film calibration work and dynamic range improvements. Changes to the processing chemistry and the resulting changes in dynamic range and x-ray sensitivity are discussed

  11. AGARD Flight Test Techniques Series. Volume 9. Aircraft Exterior Noise Measurement and Analysis Techniques. (Le Bruit a l’Exterieur des Aeronefs: Techniques de Mesure et d’Analyse)

    Science.gov (United States)

    1991-04-01

    sugeseed to me to write ui AGARDograpit on A~rlmaft Noie Mms dsurnent Anallysis Techniques’. Being overjoyed, and quite honoured. I realdily agreed to his...Gelt& I )nd Delta 2 terms) Wb) Source Noise Correction - Jet Engine Noise ’) ielts 3 term) (c) Snor"e Noise Correction - Propeller Noise (Delta 3...printed out, since it is impractical to write these down by hand durilg th,. test). One track on each tape-recorder must be used to record a time code

  12. Effect of intra-abdominal volume increment technique for the treatment of intra-abdominal hypertension on the liver after resuscitation of hemorrhagic shock in pig

    Directory of Open Access Journals (Sweden)

    Zheng-gang WANG

    2012-02-01

    Full Text Available Objective  To observe the effect of vacuum sealing drainage (VSD assisted intra-abdominal volume increment (IAVI technique on the liver in the treatment of intra-abdominal hypertension (IAH following hemorrhagic shock resuscitation in pigs. Methods  Twelve healthy mini-pigs (Bama, Guangxi were selected for bloodletting from the femoral artery to reproduce hemorrhagic shock model (mean arterial blood pressure, 50mmHg, 1h, and IAH model was successfully reproduced in eight pigs by partial occlusion of portal vein. The eight pigs were randomly divided into the intra-abdominal volume increment treatment (IT group (n=4 and sham operation control (SC group (n=4. Vesical pressure (VP and inferior vena cava pressure (IVCP were observed before shock, 2h after IAH, and 22h after IAVI treatment. Aspartate aminotransferase (AST and alanine aminotransferase (ALT were measured. In addition, the ratio of the abdominal anteroposterior diameter to the transverse diameter was assessed, and the liver CT values were measured after enhanced CT scanning. The pigs were sacrificed 26h after operation. Liver specimens were collected to measure the ratio of wet weight to dry weight and pathological examination. Results  The VP in 8 IAH pigs was 21.16±4.63mmHg. The ratio of abdominal anteroposterior diameter to the transverse diameter increased remarkably 2h after IAH compared with that before shock (1.22±1.41 vs 0.96±0.08, PPvs 42.73±4.92HU, PPPvs 5.14±0.71, PConclusions  The established model could better reproduce the symptoms of IAH after hemorrhagic shock and fluid resuscitation, accompanied by liver damage. IAVI helps to relieve liver functional disturbance after IAH, which is related to decreased intra-abdominal pressure and hypoxia-ischemia of the liver.

  13. Impact of preoperative calculation of nephron volume loss on future of partial nephrectomy techniques; planning a strategic roadmap for improving functional preservation and securing oncological safety.

    Science.gov (United States)

    Rha, Koon H; Abdel Raheem, Ali; Park, Sung Y; Kim, Kwang H; Kim, Hyung J; Koo, Kyo C; Choi, Young D; Jung, Byung H; Lee, Sang K; Lee, Won K; Krishnan, Jayram; Shin, Tae Y; Cho, Jin-Seon

    2017-11-01

    To assess the correlation of the resected and ischaemic volume (RAIV), which is a preoperatively calculated volume of nephron loss, with the amount of postoperative renal function (PRF) decline after minimally invasive partial nephrectomy (PN) in a multi-institutional dataset. We identified 348 patients from March 2005 to December 2013 at six institutions. Data on all cases of laparoscopic (n = 85) and robot-assisted PN (n = 263) performed were retrospectively gathered. Univariable and multivariable linear regression analyses were used to identify the associations between various time points of PRF and the RAIV, as a continuous variable. The mean (sd) RAIV was 24.2 (29.2) cm 3 . The mean preoperative estimated glomerular filtration rate (eGFR) and the eGFRs at postoperative day 1, 6 and 36 months after PN were 91.0 and 76.8, 80.2 and 87.7 mL/min/1.73 m 2 , respectively. In multivariable linear regression analysis, the amount of decline in PRF at follow-up was significantly correlated with the RAIV (β 0.261, 0.165, 0.260 at postoperative day 1, 6 and 36 months after PN, respectively). This study has the limitation of its retrospective nature. Preoperatively calculated RAIV significantly correlates with the amount of decline in PRF during long-term follow-up. The RAIV could lead our research to the level of prediction of the amount of PRF decline after PN and thus would be appropriate for assessing the technical advantages of emerging techniques. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

  14. Density and volume measurements of reprocessing plant feed

    International Nuclear Information System (INIS)

    Platzer, R.; Carrier, M.; Neuilly, M.; Dedaldechamp, P.

    1985-05-01

    A theoretical study of the phenomenon of gas bubbles formation within a liquid led to an adaptation of the differential pressure bubbling technique for the measurement of liquid levels and densities in tanks. Experiments, carried out on a 800 liters tank with water and uranyl nitrate solutions had the double aim to study the precision attainable on volume and density measurements and to design a method for corrections of influencing factors. In parallel, procedures for transfer of known volumes through the use of siphons and for tank calibration by liquid level measurement are also investigated. The paper presents the first results obtained so far and the conclusions to be drawn for the elaboration of calibration and exploitation procedures suitables for use in reprocessing plants. The demonstration to transfer mass of solution with an accuracy of 0.1% is made [fr

  15. LLE Review Quarterly Report (April-June 2001). Volume 87

    Energy Technology Data Exchange (ETDEWEB)

    Hinterman, Thomas H. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics

    2001-06-01

    This volume of the LLE Review, covering April–June 2001, features ''A Self-Calibrating, Multichannel Streak Camera for Inertial Confinement Fusion Applications'' by Dr. W. R. Donaldson, R. Boni, R. L. Keck, and P. A. Jaanimagi. This article (p. 109) describes the 60-beam streak camera system used on OMEGA and focuses on the hardware and software calibration techniques that maximize its utility. The system can diagnose each of the beams on every target shot and can measure beam energies with 8% accuracy and timing at 7 ps rms. Beam-to-beam power variations of less than 5% can be detected. Other articles in this volume are: Evolution of Shell Nonuniformities Near Peak Compression of a Spherical Implosion; Multibeam Stimulated Brillouin Scattering from Hot Solid-Target Plasmas; Hot-Electron Effect in Superconductors and Is Applications for Radiation Sensors; and, Scaling Law for Marginal Ignition.

  16. Air Data Calibration Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility is for low altitude subsonic altimeter system calibrations of air vehicles. Mission is a direct support of the AFFTC mission. Postflight data merge is...

  17. SRHA calibration curve

    Data.gov (United States)

    U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...

  18. Calibrated Properties Model

    International Nuclear Information System (INIS)

    Ahlers, C.F.; Liu, H.H.

    2001-01-01

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the AMR Development Plan for U0035 Calibrated Properties Model REV00 (CRWMS M and O 1999c). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions

  19. Calibrated Properties Model

    International Nuclear Information System (INIS)

    Ahlers, C.; Liu, H.

    2000-01-01

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions

  20. A single model procedure for estimating tank calibration equations

    International Nuclear Information System (INIS)

    Liebetrau, A.M.

    1997-10-01

    A fundamental component of any accountability system for nuclear materials is a tank calibration equation that relates the height of liquid in a tank to its volume. Tank volume calibration equations are typically determined from pairs of height and volume measurements taken in a series of calibration runs. After raw calibration data are standardized to a fixed set of reference conditions, the calibration equation is typically fit by dividing the data into several segments--corresponding to regions in the tank--and independently fitting the data for each segment. The estimates obtained for individual segments must then be combined to obtain an estimate of the entire calibration function. This process is tedious and time-consuming. Moreover, uncertainty estimates may be misleading because it is difficult to properly model run-to-run variability and between-segment correlation. In this paper, the authors describe a model whose parameters can be estimated simultaneously for all segments of the calibration data, thereby eliminating the need for segment-by-segment estimation. The essence of the proposed model is to define a suitable polynomial to fit to each segment and then extend its definition to the domain of the entire calibration function, so that it (the entire calibration function) can be expressed as the sum of these extended polynomials. The model provides defensible estimates of between-run variability and yields a proper treatment of between-segment correlations. A portable software package, called TANCS, has been developed to facilitate the acquisition, standardization, and analysis of tank calibration data. The TANCS package was used for the calculations in an example presented to illustrate the unified modeling approach described in this paper. With TANCS, a trial calibration function can be estimated and evaluated in a matter of minutes

  1. Obtention of tumor volumes in PET images stacks using techniques of colored image segmentation; Obtencao de volumes tumorais em pilhas de imagens PET usando tecnicas de segmentacao de imagens coloridas

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Jose W.; Lopes Filho, Ferdinand J., E-mail: jose.wilson@recife.ifpe.edu.br [Instituto Federal de Educacao e Tecnologia de Pernambuco (IFPE) Recife, PE (Brazil); Vieira, Igor F., E-mail: igoradiologia@gmail.com [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Lima, Fernando R.A.; Cordeiro, Landerson P., E-mail: leoxofisico@gmail.com, E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-NE), Recife, PE (Brazil)

    2014-07-01

    This work demonstrated step by step how to segment color images of the chest of an adult in order to separate the tumor volume without significantly changing the values of the components R (Red), G (Green) and B (blue) of the colors of the pixels. For having information which allow to build color map you need to segment and classify the colors present at appropriate intervals in images. The used segmentation technique is to select a small rectangle with color samples in a given region and then erase with a specific color called 'rubber' the other regions of image. The tumor region was segmented into one of the images available and the procedure is displayed in tutorial format. All necessary computational tools have been implemented in DIP (Digital Image Processing), software developed by the authors. The results obtained, in addition to permitting the construction the colorful map of the distribution of the concentration of activity in PET images will also be useful in future work to enter tumors in voxel phantoms in order to perform dosimetric assessments.

  2. Scanner calibration revisited

    Directory of Open Access Journals (Sweden)

    Pozhitkov Alexander E

    2010-07-01

    Full Text Available Abstract Background Calibration of a microarray scanner is critical for accurate interpretation of microarray results. Shi et al. (BMC Bioinformatics, 2005, 6, Art. No. S11 Suppl. 2. reported usage of a Full Moon BioSystems slide for calibration. Inspired by the Shi et al. work, we have calibrated microarray scanners in our previous research. We were puzzled however, that most of the signal intensities from a biological sample fell below the sensitivity threshold level determined by the calibration slide. This conundrum led us to re-investigate the quality of calibration provided by the Full Moon BioSystems slide as well as the accuracy of the analysis performed by Shi et al. Methods Signal intensities were recorded on three different microarray scanners at various photomultiplier gain levels using the same calibration slide from Full Moon BioSystems. Data analysis was conducted on raw signal intensities without normalization or transformation of any kind. Weighted least-squares method was used to fit the data. Results We found that initial analysis performed by Shi et al. did not take into account autofluorescence of the Full Moon BioSystems slide, which led to a grossly distorted microarray scanner response. Our analysis revealed that a power-law function, which is explicitly accounting for the slide autofluorescence, perfectly described a relationship between signal intensities and fluorophore quantities. Conclusions Microarray scanners respond in a much less distorted fashion than was reported by Shi et al. Full Moon BioSystems calibration slides are inadequate for performing calibration. We recommend against using these slides.

  3. Calibration of thermoluminiscent materials

    International Nuclear Information System (INIS)

    Bos, A.J.J.

    1989-07-01

    In this report the relation between exposure and absorbed radiation dose in various materials is represented, on the base of recent data. With the help of this a calibration procedure for thermoluminescent materials, adapted to the IRI radiation standard is still the exposure in rontgen. In switching to the air kerma standard the calibration procedure will have to be adapted. (author). 6 refs.; 4 tabs

  4. Calibrating nacelle lidars

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, M.

    2013-01-15

    Nacelle mounted, forward looking wind lidars are beginning to be used to provide reference wind speed measurements for the power performance testing of wind turbines. In such applications, a formal calibration procedure with a corresponding uncertainty assessment will be necessary. This report presents four concepts for performing such a nacelle lidar calibration. Of the four methods, two are found to be immediately relevant and are pursued in some detail. The first of these is a line of sight calibration method in which both lines of sight (for a two beam lidar) are individually calibrated by accurately aligning the beam to pass close to a reference wind speed sensor. A testing procedure is presented, reporting requirements outlined and the uncertainty of the method analysed. It is seen that the main limitation of the line of sight calibration method is the time required to obtain a representative distribution of radial wind speeds. An alternative method is to place the nacelle lidar on the ground and incline the beams upwards to bisect a mast equipped with reference instrumentation at a known height and range. This method will be easier and faster to implement and execute but the beam inclination introduces extra uncertainties. A procedure for conducting such a calibration is presented and initial indications of the uncertainties given. A discussion of the merits and weaknesses of the two methods is given together with some proposals for the next important steps to be taken in this work. (Author)

  5. Dynamic photogrammetric calibration of industrial robots

    Science.gov (United States)

    Maas, Hans-Gerd

    1997-07-01

    Today's developments in industrial robots focus on aims like gain of flexibility, improvement of the interaction between robots and reduction of down-times. A very important method to achieve these goals are off-line programming techniques. In contrast to conventional teach-in-robot programming techniques, where sequences of actions are defined step-by- step via remote control on the real object, off-line programming techniques design complete robot (inter-)action programs in a CAD/CAM environment. This poses high requirements to the geometric accuracy of a robot. While the repeatability of robot poses in the teach-in mode is often better than 0.1 mm, the absolute pose accuracy potential of industrial robots is usually much worse due to tolerances, eccentricities, elasticities, play, wear-out, load, temperature and insufficient knowledge of model parameters for the transformation from poses into robot axis angles. This fact necessitates robot calibration techniques, including the formulation of a robot model describing kinematics and dynamics of the robot, and a measurement technique to provide reference data. Digital photogrammetry as an accurate, economic technique with realtime potential offers itself for this purpose. The paper analyzes the requirements posed to a measurement technique by industrial robot calibration tasks. After an overview on measurement techniques used for robot calibration purposes in the past, a photogrammetric robot calibration system based on off-the- shelf lowcost hardware components will be shown and results of pilot studies will be discussed. Besides aspects of accuracy, reliability and self-calibration in a fully automatic dynamic photogrammetric system, realtime capabilities are discussed. In the pilot studies, standard deviations of 0.05 - 0.25 mm in the three coordinate directions could be achieved over a robot work range of 1.7 X 1.5 X 1.0 m3. The realtime capabilities of the technique allow to go beyond kinematic robot

  6. Highly Conformal Craniospinal Radiotherapy Techniques Can Underdose the Cranial Clinical Target Volume if Leptomeningeal Extension through Skull Base Exit Foramina is not Contoured.

    Science.gov (United States)

    Noble, D J; Ajithkumar, T; Lambert, J; Gleeson, I; Williams, M V; Jefferies, S J

    2017-07-01

    Craniospinal irradiation (CSI) remains a crucial treatment for patients with medulloblastoma. There is uncertainty about how to manage meningeal surfaces and cerebrospinal fluid (CSF) that follows cranial nerves exiting skull base foramina. The purpose of this study was to assess plan quality and dose coverage of posterior cranial fossa foramina with both photon and proton therapy. We analysed the radiotherapy plans of seven patients treated with CSI for medulloblastoma and primitive neuro-ectodermal tumours and three with ependymoma (total n = 10). Four had been treated with a field-based technique and six with TomoTherapy™. The internal acoustic meatus (IAM), jugular foramen (JF) and hypoglossal canal (HC) were contoured and added to the original treatment clinical target volume (Plan_CTV) to create a Test_CTV. This was grown to a test planning target volume (Test_PTV) for comparison with a Plan_PTV. Using Plan_CTV and Plan_PTV, proton plans were generated for all 10 cases. The following dosimetry data were recorded: conformity (dice similarity coefficient) and homogeneity index (D 2  - D 98 /D 50 ) as well as median and maximum dose (D 2% ) to Plan_PTV, V 95% and minimum dose (D 99.9% ) to Plan_CTV and Test_CTV and Plan_PTV and Test_PTV, V 95% and minimum dose (D 98% ) to foramina PTVs. Proton and TomoTherapy™ plans were more conformal (0.87, 0.86) and homogeneous (0.07, 0.04) than field-photon plans (0.79, 0.17). However, field-photon plans covered the IAM, JF and HC PTVs better than proton plans (P = 0.002, 0.004, 0.003, respectively). TomoTherapy™ plans covered the IAM and JF better than proton plans (P = 0.000, 0.002, respectively) but the result for the HC was not significant. Adding foramen CTVs/PTVs made no difference for field plans. The mean D min dropped 3.4% from Plan_PTV to Test_PTV for TomoTherapy™ (not significant) and 14.8% for protons (P = 0.001). Highly conformal CSI techniques may underdose meninges and CSF in the dural

  7. Cerebrospinal fluid volume measurements in hydrocephalic rats.

    Science.gov (United States)

    Basati, Sukhraaj; Desai, Bhargav; Alaraj, Ali; Charbel, Fady; Linninger, Andreas

    2012-10-01

    Object Experimental data about the evolution of intracranial volume and pressure in cases of hydrocephalus are limited due to the lack of available monitoring techniques. In this study, the authors validate intracranial CSF volume measurements within the lateral ventricle, while simultaneously using impedance sensors and pressure transducers in hydrocephalic animals. Methods A volume sensor was fabricated and connected to a catheter that was used as a shunt to withdraw CSF. In vitro bench-top calibration experiments were created to provide data for the animal experiments and to validate the sensors. To validate the measurement technique in a physiological system, hydrocephalus was induced in weanling rats by kaolin injection into the cisterna magna. At 28 days after induction, the sensor was implanted into the lateral ventricles. After sealing the skull using dental cement, an acute CSF drainage/infusion protocol consisting of 4 sequential phases was performed with a pump. Implant location was confirmed via radiography using intraventricular iohexol contrast administration. Results Controlled CSF shunting in vivo with hydrocephalic rats resulted in precise and accurate sensor measurements (r = 0.98). Shunting resulted in a 17.3% maximum measurement error between measured volume and actual volume as assessed by a Bland-Altman plot. A secondary outcome confirmed that both ventricular volume and intracranial pressure decreased during CSF shunting and increased during infusion. Ventricular enlargement consistent with successful hydrocephalus induction was confirmed using imaging, as well as postmortem. These results indicate that volume monitoring is feasible for clinical cases of hydrocephalus. Conclusions This work marks a departure from traditional shunting systems currently used to treat hydrocephalus. The overall clinical application is to provide alternative monitoring and treatment options for patients. Future work includes development and testing of a chronic

  8. INTRODUCING NOVEL GENERATION OF HIGH ACCURACY CAMERA OPTICAL-TESTING AND CALIBRATION TEST-STANDS FEASIBLE FOR SERIES PRODUCTION OF CAMERAS

    Directory of Open Access Journals (Sweden)

    M. Nekouei Shahraki

    2015-12-01

    Full Text Available The recent advances in the field of computer-vision have opened the doors of many opportunities for taking advantage of these techniques and technologies in many fields and applications. Having a high demand for these systems in today and future vehicles implies a high production volume of video cameras. The above criterions imply that it is critical to design test systems which deliver fast and accurate calibration and optical-testing capabilities. In this paper we introduce new generation of test-stands delivering high calibration quality in single-shot calibration of fisheye surround-view cameras. This incorporates important geometric features from bundle-block calibration, delivers very high (sub-pixel calibration accuracy, makes possible a very fast calibration procedure (few seconds, and realizes autonomous calibration via machines. We have used the geometrical shape of a Spherical Helix (Type: 3D Spherical Spiral with special geometrical characteristics, having a uniform radius which corresponds to the uniform motion. This geometrical feature was mechanically realized using three dimensional truncated icosahedrons which practically allow the implementation of a spherical helix on multiple surfaces. Furthermore the test-stand enables us to perform many other important optical tests such as stray-light testing, enabling us to evaluate the certain qualities of the camera optical module.

  9. Chaos, Consternation and CALIPSO Calibration: New Strategies for Calibrating the CALIOP 1064 nm Channel

    Science.gov (United States)

    Vaughan, Mark; Garnier, Anne; Liu, Zhaoyan; Josset, Damien; Hu, Yongxiang; Lee, Kam-Pui; Hunt, William; Vernier, Jean-Paul; Rodier, Sharon; Pelon, Jaques; hide

    2012-01-01

    The very low signal-to-noise ratios of the 1064 nm CALIOP molecular backscatter signal make it effectively impossible to employ the "clear air" normalization technique typically used to calibrate elastic back-scatter lidars. The CALIPSO mission has thus chosen to cross-calibrate their 1064 nm measurements with respect to the 532 nm data using the two-wavelength backscatter from cirrus clouds. In this paper we discuss several known issues in the version 3 CALIOP 1064 nm calibration procedure, and describe the strategies that will be employed in the version 4 data release to surmount these problems.

  10. Comparison of different multi-objective calibration criteria using a conceptual rainfall-runoff model of flood events

    Directory of Open Access Journals (Sweden)

    R. Moussa

    2009-04-01

    Full Text Available A conceptual lumped rainfall-runoff flood event model was developed and applied on the Gardon catchment located in Southern France and various single-objective and multi-objective functions were used for its calibration. The model was calibrated on 15 events and validated on 14 others. The results of both the calibration and validation phases are compared on the basis of their performance with regards to six criteria, three global criteria and three relative criteria representing volume, peakflow, and the root mean square error. The first type of criteria gives more weight to large events whereas the second considers all events to be of equal weight. The results show that the calibrated parameter values are dependent on the type of criteria used. Significant trade-offs are observed between the different objectives: no unique set of parameters is able to satisfy all objectives simultaneously. Instead, the solution to the calibration problem is given by a set of Pareto optimal solutions. From this set of optimal solutions, a balanced aggregated objective function is proposed, as a compromise between up to three objective functions. The single-objective and multi-objective calibration strategies are compared both in terms of parameter variation bounds and simulation quality. The results of this study indicate that two well chosen and non-redundant objective functions are sufficient to calibrate the model and that the use of three objective functions does not necessarily yield different results. The problems of non-uniqueness in model calibration, and the choice of the adequate objective functions for flood event models, emphasise the importance of the modeller's intervention. The recent advances in automatic optimisation techniques do not minimise the user's responsibility, who has to choose multiple criteria based on the aims of the study, his appreciation on the errors induced by data and model structure and his knowledge of the

  11. In situ calibration of TFTR neutron detectors

    International Nuclear Information System (INIS)

    Hendel, H.W.; Palladino, R.W.; Barnes, C.W.; Diesso, M.; Felt, J.S.; Jassby, D.L.; Johnson, L.C.; Ku, L.; Liu, Q.P.; Motley, R.W.; Murphy, H.B.; Murphy, J.; Nieschmidt, E.B.; Roberts, J.A.; Saito, T.; Strachan, J.D.; Waszazak, R.J.; Young, K.M.

    1990-01-01

    We report results of the TFTR fission detector calibration performed in December 1988. A NBS-traceable, remotely controlled 252 Cf neutron source was moved toroidally through the TFTR vacuum vessel. Detection efficiencies for two 235 U detectors were measured for 930 locations of the neutron point source in toroidal scans at 16 different major radii and vertical heights. These scans effectively simulated the volume-distributed plasma neutron source and the volume-integrated detection efficiency was found to be insensitive to plasma position. The Campbell mode is useful due to its large overlap with the count rate mode and large dynamic range. The resulting absolute plasma neutron source calibration has an uncertainty of ±13%

  12. Effects of line fiducial parameters and beamforming on ultrasound calibration

    OpenAIRE

    Ameri, Golafsoun; Baxter, John S. H.; McLeod, A. Jonathan; Peters, Terry M.; Chen, Elvis C. S.

    2017-01-01

    Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom mater...

  13. Whole-organ perfusion of the pancreas using dynamic volume CT in patients with primary pancreas carcinoma: acquisition technique, post-processing and initial results

    International Nuclear Information System (INIS)

    Kandel, Sonja; Kloeters, Christian; Meyer, Henning; Hein, Patrick; Rogalla, Patrik; Hilbig, Andreas

    2009-01-01

    The purpose of this study was to evaluate a whole-organ perfusion protocol of the pancreas in patients with primary pancreas carcinoma and to analyse perfusion differences between normal and diseased pancreatic tissue. Thirty patients with primary pancreatic malignancy were imaged on a 320-slice CT unit. Twenty-nine cancers were histologically proven. CT data acquisition was started manually after contrast-material injection (8 ml/s, 350 mg iodine/ml) and dynamic density measurements in the right ventricle. After image registration, perfusion was determined with the gradient-relationship technique and volume regions-of-interest were defined for perfusion measurements. Contrast time-density curves and perfusion maps were generated. Statistical analysis was performed using the Kolmogorov-Smirnov test for analysis of normal distribution and Kruskal-Wallis test (nonparametric ANOVA) with Bonferroni correction for multiple stacked comparisons. In all 30 patients the entire pancreas was imaged, and registration could be completed in all cases. Perfusion of pancreatic carcinomas was significantly lower than of normal pancreatic tissue (P < 0.001) and could be visualized on colored perfusion maps. The 320-slice CT allows complete dynamic visualization of the pancreas and enables calculation of whole-organ perfusion maps. Perfusion imaging carries the potential to improve detection of pancreatic cancers due to the perfusion differences. (orig.)

  14. Flat-Panel Detector—Based Volume Computed Tomography: A Novel 3D Imaging Technique to Monitor Osteolytic Bone Lesions in a Mouse Tumor Metastasis Model

    Directory of Open Access Journals (Sweden)

    Jeannine Missbach-Guentner

    2007-09-01

    Full Text Available Skeletal metastasis is an important cause of mortality in patients with breast cancer. Hence, animal models, in combination with various imaging techniques, are in high demand for preclinical assessment of novel therapies. We evaluated the applicability of flat-panel volume computed tomography (fpVCT to noninvasive detection of osteolytic bone metastases that develop in severe immunodeficient mice after intracardial injection of MDA-MB-231 breast cancer cells. A single fpVCT scan at 200-wm isotropic resolution was employed to detect osteolysis within the entire skeleton. Osteolytic lesions identified by fpVCT correlated with Faxitron X-ray analysis and were subsequently confirmed by histopathological examination. Isotropic three-dimensional image data sets obtained by fpVCT were the basis for the precise visualization of the extent of the lesion within the cortical bone and for the measurement of bone loss. Furthermore, fpVCT imaging allows continuous monitoring of growth kinetics for each metastatic site and visualization of lesions in more complex regions of the skeleton, such as the skull. Our findings suggest that fpVCT is a powerful tool that can be used to monitor the occurrence and progression of osteolytic lesions in vivo and can be further developed to monitor responses to antimetastatic therapies over the course of the disease.

  15. A dual resolution measurement based Monte Carlo simulation technique for detailed dose analysis of small volume organs in the skull base region

    International Nuclear Information System (INIS)

    Yeh, Chi-Yuan; Tung, Chuan-Jung; Chao, Tsi-Chain; Lin, Mu-Han; Lee, Chung-Chi

    2014-01-01

    The purpose of this study was to examine dose distribution of a skull base tumor and surrounding critical structures in response to high dose intensity-modulated radiosurgery (IMRS) with Monte Carlo (MC) simulation using a dual resolution sandwich phantom. The measurement-based Monte Carlo (MBMC) method (Lin et al., 2009) was adopted for the study. The major components of the MBMC technique involve (1) the BEAMnrc code for beam transport through the treatment head of a Varian 21EX linear accelerator, (2) the DOSXYZnrc code for patient dose simulation and (3) an EPID-measured efficiency map which describes non-uniform fluence distribution of the IMRS treatment beam. For the simulated case, five isocentric 6 MV photon beams were designed to deliver a total dose of 1200 cGy in two fractions to the skull base tumor. A sandwich phantom for the MBMC simulation was created based on the patient's CT scan of a skull base tumor [gross tumor volume (GTV)=8.4 cm 3 ] near the right 8th cranial nerve. The phantom, consisted of a 1.2-cm thick skull base region, had a voxel resolution of 0.05×0.05×0.1 cm 3 and was sandwiched in between 0.05×0.05×0.3 cm 3 slices of a head phantom. A coarser 0.2×0.2×0.3 cm 3 single resolution (SR) phantom was also created for comparison with the sandwich phantom. A particle history of 3×10 8 for each beam was used for simulations of both the SR and the sandwich phantoms to achieve a statistical uncertainty of <2%. Our study showed that the planning target volume (PTV) receiving at least 95% of the prescribed dose (VPTV95) was 96.9%, 96.7% and 99.9% for the TPS, SR, and sandwich phantom, respectively. The maximum and mean doses to large organs such as the PTV, brain stem, and parotid gland for the TPS, SR and sandwich MC simulations did not show any significant difference; however, significant dose differences were observed for very small structures like the right 8th cranial nerve, right cochlea, right malleus and right semicircular

  16. DebrisInterMixing-2.3: a finite volume solver for three-dimensional debris-flow simulations with two calibration parameters – Part 2: Model validation with experiments

    Directory of Open Access Journals (Sweden)

    A. von Boetticher

    2017-11-01

    Full Text Available Here, we present validation tests of the fluid dynamic solver presented in von Boetticher et al. (2016, simulating both laboratory-scale and large-scale debris-flow experiments. The new solver combines a Coulomb viscoplastic rheological model with a Herschel–Bulkley model based on material properties and rheological characteristics of the analyzed debris flow. For the selected experiments in this study, all necessary material properties were known – the content of sand, clay (including its mineral composition and gravel as well as the water content and the angle of repose of the gravel. Given these properties, two model parameters are sufficient for calibration, and a range of experiments with different material compositions can be reproduced by the model without recalibration. One calibration parameter, the Herschel–Bulkley exponent, was kept constant for all simulations. The model validation focuses on different case studies illustrating the sensitivity of debris flows to water and clay content, channel curvature, channel roughness and the angle of repose. We characterize the accuracy of the model using experimental observations of flow head positions, front velocities, run-out patterns and basal pressures.

  17. Direct megavoltage photon calibration service in Australia

    International Nuclear Information System (INIS)

    Butler, D.J.; Ramanthan, G.; Oliver, C.; Cole, A.; Harty, P.D.; Wright, T.; Webb, D.V.; Lye, J.; Followill, D.S.

    2014-01-01

    The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) maintains the Australian primary standard of absorbed dose. Until recently, the standard was used to calibrate ionisation chambers only in 60 Co gamma rays. These chambers are then used by radiotherapy clinics to determine linac output, using a correction factor (k Q ) to take into account the different spectra of 60 Co and the linac. Over the period 2010–2013, ARPANSA adapted the primary standard to work in megavoltage linac beams, and has developed a calibration service at three photon beams (6, 10 and 18 MV) from an Elekta Synergy linac. We describe the details of the new calibration service, the method validation and the use of the new calibration factors with the International Atomic Energy Agency’s TRS-398 dosimetry Code of Practice. The expected changes in absorbed dose measurements in the clinic when shifting from 60 Co to the direct calibration are determined. For a Farmer chamber (model 2571), the measured chamber calibration coefficient is expected to be reduced by 0.4, 1.0 and 1.1 % respectively for these three beams when compared to the factor derived from 60 Co. These results are in overall agreement with international absorbed dose standards and calculations by Muir and Rogers in 2010 of k Q factors using Monte Carlo techniques. The reasons for and against moving to the new service are discussed in the light of the requirements of clinical dosimetry.

  18. Comparison of infusion pumps calibration methods

    Science.gov (United States)

    Batista, Elsa; Godinho, Isabel; do Céu Ferreira, Maria; Furtado, Andreia; Lucas, Peter; Silva, Claudia

    2017-12-01

    Nowadays, several types of infusion pump are commonly used for drug delivery, such as syringe pumps and peristaltic pumps. These instruments present different measuring features and capacities according to their use and therapeutic application. In order to ensure the metrological traceability of these flow and volume measuring equipment, it is necessary to use suitable calibration methods and standards. Two different calibration methods can be used to determine the flow error of infusion pumps. One is the gravimetric method, considered as a primary method, commonly used by National Metrology Institutes. The other calibration method, a secondary method, relies on an infusion device analyser (IDA) and is typically used by hospital maintenance offices. The suitability of the IDA calibration method was assessed by testing several infusion instruments at different flow rates using the gravimetric method. In addition, a measurement comparison between Portuguese Accredited Laboratories and hospital maintenance offices was performed under the coordination of the Portuguese Institute for Quality, the National Metrology Institute. The obtained results were directly related to the used calibration method and are presented in this paper. This work has been developed in the framework of the EURAMET projects EMRP MeDD and EMPIR 15SIP03.

  19. Calibration of detector efficiency of neutron detector

    International Nuclear Information System (INIS)

    Guo Hongsheng; He Xijun; Xu Rongkun; Peng Taiping

    2001-01-01

    BF 3 neutron detector has been set up. Detector efficiency is calibrated by associated particle technique. It is about 3.17 x 10 -4 (1 +- 18%). Neutron yield of neutron generator per pulse (10 7 /pulse) is measured by using the detector

  20. POLCAL - POLARIMETRIC RADAR CALIBRATION

    Science.gov (United States)

    Vanzyl, J.

    1994-01-01

    Calibration of polarimetric radar systems is a field of research in which great progress has been made over the last few years. POLCAL (Polarimetric Radar Calibration) is a software tool intended to assist in the calibration of Synthetic Aperture Radar (SAR) systems. In particular, POLCAL calibrates Stokes matrix format data produced as the standard product by the NASA/Jet Propulsion Laboratory (JPL) airborne imaging synthetic aperture radar (AIRSAR). POLCAL was designed to be used in conjunction with data collected by the NASA/JPL AIRSAR system. AIRSAR is a multifrequency (6 cm, 24 cm, and 68 cm wavelength), fully polarimetric SAR system which produces 12 x 12 km imagery at 10 m resolution. AIRSTAR was designed as a testbed for NASA's Spaceborne Imaging Radar program. While the images produced after 1991 are thought to be calibrated (phase calibrated, cross-talk removed, channel imbalance removed, and absolutely calibrated), POLCAL can and should still be used to check the accuracy of the calibration and to correct it if necessary. Version 4.0 of POLCAL is an upgrade of POLCAL version 2.0 released to AIRSAR investigators in June, 1990. New options in version 4.0 include automatic absolute calibration of 89/90 data, distributed target analysis, calibration of nearby scenes with calibration parameters from a scene with corner reflectors, altitude or roll angle corrections, and calibration of errors introduced by known topography. Many sources of error can lead to false conclusions about the nature of scatterers on the surface. Errors in the phase relationship between polarization channels result in incorrect synthesis of polarization states. Cross-talk, caused by imperfections in the radar antenna itself, can also lead to error. POLCAL reduces cross-talk and corrects phase calibration without the use of ground calibration equipment. Removing the antenna patterns during SAR processing also forms a very important part of the calibration of SAR data. Errors in the

  1. Calibration Under Uncertainty.

    Energy Technology Data Exchange (ETDEWEB)

    Swiler, Laura Painton; Trucano, Timothy Guy

    2005-03-01

    This report is a white paper summarizing the literature and different approaches to the problem of calibrating computer model parameters in the face of model uncertainty. Model calibration is often formulated as finding the parameters that minimize the squared difference between the model-computed data (the predicted data) and the actual experimental data. This approach does not allow for explicit treatment of uncertainty or error in the model itself: the model is considered the %22true%22 deterministic representation of reality. While this approach does have utility, it is far from an accurate mathematical treatment of the true model calibration problem in which both the computed data and experimental data have error bars. This year, we examined methods to perform calibration accounting for the error in both the computer model and the data, as well as improving our understanding of its meaning for model predictability. We call this approach Calibration under Uncertainty (CUU). This talk presents our current thinking on CUU. We outline some current approaches in the literature, and discuss the Bayesian approach to CUU in detail.

  2. Cumulative sum quality control for calibrated breast density measurements

    International Nuclear Information System (INIS)

    Heine, John J.; Cao Ke; Beam, Craig

    2009-01-01

    Purpose: Breast density is a significant breast cancer risk factor. Although various methods are used to estimate breast density, there is no standard measurement for this important factor. The authors are developing a breast density standardization method for use in full field digital mammography (FFDM). The approach calibrates for interpatient acquisition technique differences. The calibration produces a normalized breast density pixel value scale. The method relies on first generating a baseline (BL) calibration dataset, which required extensive phantom imaging. Standardizing prospective mammograms with calibration data generated in the past could introduce unanticipated error in the standardized output if the calibration dataset is no longer valid. Methods: Sample points from the BL calibration dataset were imaged approximately biweekly over an extended timeframe. These serial samples were used to evaluate the BL dataset reproducibility and quantify the serial calibration accuracy. The cumulative sum (Cusum) quality control method was used to evaluate the serial sampling. Results: There is considerable drift in the serial sample points from the BL calibration dataset that is x-ray beam dependent. Systematic deviation from the BL dataset caused significant calibration errors. This system drift was not captured with routine system quality control measures. Cusum analysis indicated that the drift is a sign of system wear and eventual x-ray tube failure. Conclusions: The BL calibration dataset must be monitored and periodically updated, when necessary, to account for sustained system variations to maintain the calibration accuracy.

  3. Cumulative sum quality control for calibrated breast density measurements

    Energy Technology Data Exchange (ETDEWEB)

    Heine, John J.; Cao Ke; Beam, Craig [Cancer Prevention and Control Division, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, Florida 33612 (United States); Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago, 1603 W. Taylor St., Chicago, Illinois 60612 (United States)

    2009-12-15

    Purpose: Breast density is a significant breast cancer risk factor. Although various methods are used to estimate breast density, there is no standard measurement for this important factor. The authors are developing a breast density standardization method for use in full field digital mammography (FFDM). The approach calibrates for interpatient acquisition technique differences. The calibration produces a normalized breast density pixel value scale. The method relies on first generating a baseline (BL) calibration dataset, which required extensive phantom imaging. Standardizing prospective mammograms with calibration data generated in the past could introduce unanticipated error in the standardized output if the calibration dataset is no longer valid. Methods: Sample points from the BL calibration dataset were imaged approximately biweekly over an extended timeframe. These serial samples were used to evaluate the BL dataset reproducibility and quantify the serial calibration accuracy. The cumulative sum (Cusum) quality control method was used to evaluate the serial sampling. Results: There is considerable drift in the serial sample points from the BL calibration dataset that is x-ray beam dependent. Systematic deviation from the BL dataset caused significant calibration errors. This system drift was not captured with routine system quality control measures. Cusum analysis indicated that the drift is a sign of system wear and eventual x-ray tube failure. Conclusions: The BL calibration dataset must be monitored and periodically updated, when necessary, to account for sustained system variations to maintain the calibration accuracy.

  4. Calibrating the neutron moisture meter: Precision and economy

    International Nuclear Information System (INIS)

    Akhter, J.; Waheed, R.A.; Hignett, C.T.; Greacen, E.L.

    2000-01-01

    Established laboratory and field calibration procedures for the neutron moisture meter are demonstrated on a uniform soil and alternative, low cost procedures on a duplex, less uniform soil. The effect of field variability on the calibration methodology is discussed with the aim of optimising calibration reliability at minimal cost. The difference between calibration for a soil material, or for a field (a range of soil materials) is considered. In particular, calibration for the estimation of water content change is shown to be a different problem from calibration for the estimation of water content in a variable field. Techniques aimed at detecting field variability problems during calibration are suggested, and methods for optimising the results for the intended use of the instrument are outlined. Pairing of calibration tubes, alternative methods of analysis of calibration data, and use of other information from the field to measure its variability, can improve the precision of calibration procedures to the point where minimal calibration effort, with careful analysis, can provide reliable results. (author)

  5. Automation is an Effective Way to Improve Quality of Verification (Calibration) of Measuring Instruments

    Science.gov (United States)

    Golobokov, M.; Danilevich, S.

    2018-04-01

    In order to assess calibration reliability and automate such assessment, procedures for data collection and simulation study of thermal imager calibration procedure have been elaborated. The existing calibration techniques do not always provide high reliability. A new method for analyzing the existing calibration techniques and developing new efficient ones has been suggested and tested. A type of software has been studied that allows generating instrument calibration reports automatically, monitoring their proper configuration, processing measurement results and assessing instrument validity. The use of such software allows reducing man-hours spent on finalization of calibration data 2 to 5 times and eliminating a whole set of typical operator errors.

  6. Ibis ground calibration

    International Nuclear Information System (INIS)

    Bird, A.J.; Barlow, E.J.; Tikkanen, T.; Bazzano, A.; Del Santo, M.; Ubertini, P.; Blondel, C.; Laurent, P.; Lebrun, F.; Di Cocco, G.; Malaguti, E.; Gabriele, M.; La Rosa, G.; Segreto, A.; Quadrini, E.; Volkmer, R.

    2003-01-01

    We present an overview of results obtained from IBIS ground calibrations. The spectral and spatial characteristics of the detector planes and surrounding passive materials have been determined through a series of calibration campaigns. Measurements of pixel gain, energy resolution, detection uniformity, efficiency and imaging capability are presented. The key results obtained from the ground calibration have been: - optimization of the instrument tunable parameters, - determination of energy linearity for all detection modes, - determination of energy resolution as a function of energy through the range 20 keV - 3 MeV, - demonstration of imaging capability in each mode, - measurement of intrinsic detector non-uniformity and understanding of the effects of passive materials surrounding the detector plane, and - discovery (and closure) of various leakage paths through the passive shielding system

  7. Bayesian Calibration of Thermodynamic Databases and the Role of Kinetics

    Science.gov (United States)

    Wolf, A. S.; Ghiorso, M. S.

    2017-12-01

    Self-consistent thermodynamic databases of geologically relevant materials (like Berman, 1988; Holland and Powell, 1998, Stixrude & Lithgow-Bertelloni 2011) are crucial for simulating geological processes as well as interpreting rock samples from the field. These databases form the backbone of our understanding of how fluids and rocks interact at extreme planetary conditions. Considerable work is involved in their construction from experimental phase reaction data, as they must self-consistently describe the free energy surfaces (including relative offsets) of potentially hundreds of interacting phases. Standard database calibration methods typically utilize either linear programming or least squares regression. While both produce a viable model, they suffer from strong limitations on the training data (which must be filtered by hand), along with general ignorance of many of the sources of experimental uncertainty. We develop a new method for calibrating high P-T thermodynamic databases for use in geologic applications. The model is designed to handle pure solid endmember and free fluid phases and can be extended to include mixed solid solutions and melt phases. This new calibration effort utilizes Bayesian techniques to obtain optimal parameter values together with a full family of statistically acceptable models, summarized by the posterior. Unlike previous efforts, the Bayesian Logistic Uncertain Reaction (BLUR) model directly accounts for both measurement uncertainties and disequilibrium effects, by employing a kinetic reaction model whose parameters are empirically determined from the experiments themselves. Thus, along with the equilibrium free energy surfaces, we also provide rough estimates of the activation energies, entropies, and volumes for each reaction. As a first application, we demonstrate this new method on the three-phase aluminosilicate system, illustrating how it can produce superior estimates of the phase boundaries by incorporating constraints

  8. Results of the space shuttle vehicle ascent air data system probe calibration test using a 0.07-scale external tank forebody model (68T) in the AEDC 16-foot transonic wind tunnel (IA-310), volume 2

    Science.gov (United States)

    Collette, J. G. R.

    1991-01-01

    A recalibration of the Space Shuttle Vehicle Ascent Air Data System probe was conducted in the Arnold Engineering and Development Center (AEDC) transonic wind tunnel. The purpose was to improve on the accuracy of the previous calibration in order to reduce the existing uncertainties in the system. A probe tip attached to a 0.07-scale External Tank Forebody model was tested at angles of attack of -8 to +4 degrees and sideslip angles of -4 to +4 degrees. High precision instrumentation was used to acquire pressure data at discrete Mach numbers ranging from 0.6 to 1.55. Pressure coefficient uncertainties were estimated at less than 0.0020. Additional information is given in tabular form.

  9. Results of the space shuttle vehicle ascent air data system probe calibration test using a 0.07-scale external tank forebody model (68T) in the AEDC 16-foot transonic wind tunnel (IA-310), volume 1

    Science.gov (United States)

    Collette, J. G. R.

    1991-01-01

    A recalibration of the Space Shuttle Vehicle Ascent Air Data System probe was conducted in the Arnold Engineering Development Center (AEDC) transonic wind tunnel. The purpose was to improve on the accuracy of the previous calibration in order to reduce the existing uncertainties in the system. A probe tip attached to a 0.07-scale External Tank Forebody model was tested at angles of attack of -8 to +4 degrees and sideslip angles of -4 to +4 degrees. High precision instrumentation was used to acquire pressure data at discrete Mach numbers ranging from 0.6 to 1.55. Pressure coefficient uncertainties were estimated at less than 0.0020. Data is given in graphical and tabular form.

  10. Individual dosimetry and calibration

    International Nuclear Information System (INIS)

    Hoefert, M.; Nielsen, M.

    1996-01-01

    In 1995 both the Individual Dosimetry and Calibration Sections worked under the condition of a status quo and concentrated fully on the routine part of their work. Nevertheless, the machine for printing the bar code which will be glued onto the film holder and hence identify the people when entering into high radiation areas was put into operation and most of the holders were equipped with the new identification. As far as the Calibration Section is concerned the project of the new source control system that is realized by the Technical Support Section was somewhat accelerated

  11. Calibrating Legal Judgments

    Directory of Open Access Journals (Sweden)

    Frederick Schauer

    2017-09-01

    Full Text Available Objective to study the notion and essence of legal judgments calibration the possibilities of using it in the lawenforcement activity to explore the expenses and advantages of using it. Methods dialectic approach to the cognition of social phenomena which enables to analyze them in historical development and functioning in the context of the integrity of objective and subjective factors it determined the choice of the following research methods formallegal comparative legal sociological methods of cognitive psychology and philosophy. Results In ordinary life people who assess other peoplersaquos judgments typically take into account the other judgments of those they are assessing in order to calibrate the judgment presently being assessed. The restaurant and hotel rating website TripAdvisor is exemplary because it facilitates calibration by providing access to a raterrsaquos previous ratings. Such information allows a user to see whether a particular rating comes from a rater who is enthusiastic about every place she patronizes or instead from someone who is incessantly hard to please. And even when less systematized as in assessing a letter of recommendation or college transcript calibration by recourse to the decisional history of those whose judgments are being assessed is ubiquitous. Yet despite the ubiquity and utility of such calibration the legal system seems perversely to reject it. Appellate courts do not openly adjust their standard of review based on the previous judgments of the judge whose decision they are reviewing nor do judges in reviewing legislative or administrative decisions magistrates in evaluating search warrant representations or jurors in assessing witness perception. In most legal domains calibration by reference to the prior decisions of the reviewee is invisible either because it does not exist or because reviewing bodies are unwilling to admit using what they in fact know and employ. Scientific novelty for the first

  12. Calibration of scanning Lidar

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Courtney, Michael

    This report describes the tests carried out on a scanning lidar at the DTU Test Station for large wind turbines, Høvsøre. The tests were divided in two parts. In the first part, the purpose was to obtain wind speed calibrations at two heights against two cup anemometers mounted on a mast. Additio......This report describes the tests carried out on a scanning lidar at the DTU Test Station for large wind turbines, Høvsøre. The tests were divided in two parts. In the first part, the purpose was to obtain wind speed calibrations at two heights against two cup anemometers mounted on a mast...

  13. Thermodynamic aspects of dynamical calibration of microbarometers used for IMS applications

    International Nuclear Information System (INIS)

    Starovojt, Yu.O.; Martysevich, P.N.; Kunakov, A.V.

    2006-01-01

    This paper describes the method of dynamical calibration of a microbarometer using the chamber with variable volume. The physics of this method is based on the thermodynamic process occurring inside the closed volume and on the corresponding relationships between pressure, volume and temperature changes caused by the movement of the piston attached to the inlet of the chamber. The method has been already used in several applications, however we consider essential to analyze its physical details. The paper gives the description of thermodynamic processes inside the calibration volume, the discussion of thermodynamics need and its effect on the calibration accuracy. (author)

  14. Galileo spacecraft inertial sensors in-flight calibration design

    Science.gov (United States)

    Jahanshahi, M. H.; Lai, J. Y.

    1983-01-01

    The successful navigation of Galileo depends on accurate trajectory correction maneuvers (TCM's) performed during the mission. A set of Inertial Sensor (INS) units, comprised of gyros and accelerometers, mounted on the spacecraft, are utilized to control and monitor the performance of the TCM's. To provide the optimum performance, in-flight calibrations of INS are planned. These calibrations will take place on a regular basis. In this paper, a mathematical description is given of the data reduction technique used in analyzing a typical set of calibration data. The design of the calibration and the inertial sensor error models, necessary for the above analysis, are delineated in detail.

  15. Diagnostic Value of Multidetector CT and Its Multiplanar Reformation, Volume Rendering and Virtual Bronchoscopy Postprocessing Techniques for Primary Trachea and Main Bronchus Tumors.

    Directory of Open Access Journals (Sweden)

    Mingyue Luo

    Full Text Available To evaluate the diagnostic value of multidetector CT (MDCT and its multiplanar reformation (MPR, volume rendering (VR and virtual bronchoscopy (VB postprocessing techniques for primary trachea and main bronchus tumors.Detection results of 31 primary trachea and main bronchus tumors with MDCT and its MPR, VR and VB postprocessing techniques, were analyzed retrospectively with regard to tumor locations, tumor morphologies, extramural invasions of tumors, longitudinal involvements of tumors, morphologies and extents of luminal stenoses, distances between main bronchus tumors and trachea carinae, and internal features of tumors. The detection results were compared with that of surgery and pathology.Detection results with MDCT and its MPR, VR and VB were consistent with that of surgery and pathology, included tumor locations (tracheae, n = 19; right main bronchi, n = 6; left main bronchi, n = 6, tumor morphologies (endoluminal nodes with narrow bases, n = 2; endoluminal nodes with wide bases, n = 13; both intraluminal and extraluminal masses, n = 16, extramural invasions of tumors (brokethrough only serous membrane, n = 1; 4.0 mm-56.0 mm, n = 14; no clear border with right atelectasis, n = 1, longitudinal involvements of tumors (3.0 mm, n = 1; 5.0 mm-68.0 mm, n = 29; whole right main bronchus wall and trachea carina, n = 1, morphologies of luminal stenoses (irregular, n = 26; circular, n = 3; eccentric, n = 1; conical, n = 1 and extents (mild, n = 5; moderate, n = 7; severe, n = 19, distances between main bronchus tumors and trachea carinae (16.0 mm, n = 1; invaded trachea carina, n = 1; >20.0 mm, n = 10, and internal features of tumors (fairly homogeneous densities with rather obvious enhancements, n = 26; homogeneous density with obvious enhancement, n = 1; homogeneous density without obvious enhancement, n = 1; not enough homogeneous density with obvious enhancement, n = 1; punctate calcification with obvious enhancement, n = 1; low density

  16. Diagnostic Value of Multidetector CT and Its Multiplanar Reformation, Volume Rendering and Virtual Bronchoscopy Postprocessing Techniques for Primary Trachea and Main Bronchus Tumors.

    Science.gov (United States)

    Luo, Mingyue; Duan, Chaijie; Qiu, Jianping; Li, Wenru; Zhu, Dongyun; Cai, Wenli

    2015-01-01

    To evaluate the diagnostic value of multidetector CT (MDCT) and its multiplanar reformation (MPR), volume rendering (VR) and virtual bronchoscopy (VB) postprocessing techniques for primary trachea and main bronchus tumors. Detection results of 31 primary trachea and main bronchus tumors with MDCT and its MPR, VR and VB postprocessing techniques, were analyzed retrospectively with regard to tumor locations, tumor morphologies, extramural invasions of tumors, longitudinal involvements of tumors, morphologies and extents of luminal stenoses, distances between main bronchus tumors and trachea carinae, and internal features of tumors. The detection results were compared with that of surgery and pathology. Detection results with MDCT and its MPR, VR and VB were consistent with that of surgery and pathology, included tumor locations (tracheae, n = 19; right main bronchi, n = 6; left main bronchi, n = 6), tumor morphologies (endoluminal nodes with narrow bases, n = 2; endoluminal nodes with wide bases, n = 13; both intraluminal and extraluminal masses, n = 16), extramural invasions of tumors (brokethrough only serous membrane, n = 1; 4.0 mm-56.0 mm, n = 14; no clear border with right atelectasis, n = 1), longitudinal involvements of tumors (3.0 mm, n = 1; 5.0 mm-68.0 mm, n = 29; whole right main bronchus wall and trachea carina, n = 1), morphologies of luminal stenoses (irregular, n = 26; circular, n = 3; eccentric, n = 1; conical, n = 1) and extents (mild, n = 5; moderate, n = 7; severe, n = 19), distances between main bronchus tumors and trachea carinae (16.0 mm, n = 1; invaded trachea carina, n = 1; >20.0 mm, n = 10), and internal features of tumors (fairly homogeneous densities with rather obvious enhancements, n = 26; homogeneous density with obvious enhancement, n = 1; homogeneous density without obvious enhancement, n = 1; not enough homogeneous density with obvious enhancement, n = 1; punctate calcification with obvious enhancement, n = 1; low density without

  17. Cumulative error models for the tank calibration problem

    International Nuclear Information System (INIS)

    Goldman, A.; Anderson, L.G.; Weber, J.

    1983-01-01

    The purpose of a tank calibration equation is to obtain an estimate of the liquid volume that corresponds to a liquid level measurement. Calibration experimental errors occur in both liquid level and liquid volume measurements. If one of the errors is relatively small, the calibration equation can be determined from wellknown regression and calibration methods. If both variables are assumed to be in error, then for linear cases a prototype model should be considered. Many investigators are not familiar with this model or do not have computing facilities capable of obtaining numerical solutions. This paper discusses and compares three linear models that approximate the prototype model and have the advantage of much simpler computations. Comparisons among the four models and recommendations of suitability are made from simulations and from analyses of six sets of experimental data

  18. A Study on Relative Radiometric Calibration without Calibration Field for YG-25

    Directory of Open Access Journals (Sweden)

    ZHANG Guo

    2017-08-01

    Full Text Available YG-25 is the first agility optical remote sensing satellite of China to acquire the sub-meter imagery of the earth. The side slither calibration technique is an on-orbit maneuver that has been used to flat-field image data acquired over the uniform calibration field. However, imaging to the single uniform calibration field cannot afford to calibrate the full dynamic response range of the sensor and reduces the efficiency. The paper proposes a new relative radiometric calibration method that a 90-degree yaw maneuver is performed over any non-uniform features of the Earth for YG-25. Meanwhile, we use an enhanced side slither image horizontal correction method based on line segment detector(LSDalgorithm to solve the side slither image over-shifted problem.The shifted results are compared with other horizontal correction method. The histogram match algorithm is used to calculate the relative gains of all detectors. The correctness and validity of the proposed method are validated by using the YG-25 on-board side slither data. The results prove that the mean streaking metrics of relative correction images of YG-25 is better 0.07%, the noticeable striping artifact and residual noise are removed, the calibration accuracy of side slither technique based on non-uniform features is superior to life image statistics of sensor's life span.

  19. Calibration procedure for Slocum glider deployed optical instruments.

    Science.gov (United States)

    Cetinić, Ivona; Toro-Farmer, Gerardo; Ragan, Matthew; Oberg, Carl; Jones, Burton H

    2009-08-31

    Recent developments in the field of the autonomous underwater vehicles allow the wide usage of these platforms as part of scientific experiments, monitoring campaigns and more. The vehicles are often equipped with sensors measuring temperature, conductivity, chlorophyll a fluorescence (Chl a), colored dissolved organic matter (CDOM) fluorescence, phycoerithrin (PE) fluorescence and spectral volume scattering function at 117 degrees, providing users with high resolution, real time data. However, calibration of these instruments can be problematic. Most in situ calibrations are performed by deploying complementary instrument packages or water samplers in the proximity of the glider. Laboratory calibrations of the mounted sensors are difficult due to the placement of the instruments within the body of the vehicle. For the laboratory calibrations of the Slocum glider instruments we developed a small calibration chamber where we can perform precise calibrations of the optical instruments aboard our glider, as well as sensors from other deployment platforms. These procedures enable us to obtain pre- and post-deployment calibrations for optical fluorescence instruments, which may differ due to the biofouling and other physical damage that can occur during long-term glider deployments. We found that biofouling caused significant changes in the calibration scaling factors of fluorescent sensors, suggesting the need for consistent and repetitive calibrations for gliders as proposed in this paper.

  20. ECAL Energy Flow Calibration

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    My talk will be covering my work as a whole over the course of the semester. The focus will be on using energy flow calibration in ECAL to check the precision of the corrections made by the light monitoring system used to account for transparency loss within ECAL crystals due to radiation damage over time.

  1. Calibration with Absolute Shrinkage

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Madsen, Henrik; Thyregod, Poul

    2001-01-01

    In this paper, penalized regression using the L-1 norm on the estimated parameters is proposed for chemometric je calibration. The algorithm is of the lasso type, introduced by Tibshirani in 1996 as a linear regression method with bound on the absolute length of the parameters, but a modification...

  2. Calibration bench of flowmeters

    International Nuclear Information System (INIS)

    Bremond, J.; Da Costa, D.; Calvet, A.; Vieuxmaire, C.

    1966-01-01

    This equipment is devoted to the comparison of signals from two turbines installed in the Cabri experimental loop. The signal is compared to the standard turbine. The characteristics and the performance of the calibration bench are presented. (A.L.B.)

  3. Calibration of farmer dosemeters

    International Nuclear Information System (INIS)

    Ahmad, S.S.; Anwar, K.; Arshed, W.; Mubarak, M.A.; Orfi, S.D.

    1984-08-01

    The Farmer Dosemeters of Atomic Energy Medical Centre (AEMC) Jamshoro were calibrated in the Secondary Standard Dosimetry Laboratory (SSDL) at PINSTECH, using the NPL Secondary Standard Therapy level X-ray exposure meter. The results are presented in this report. (authors)

  4. Physiotherapy ultrasound calibrations

    International Nuclear Information System (INIS)

    Gledhill, M.

    1996-01-01

    Calibration of physiotherapy ultrasound equipment has long been a problem. Numerous surveys around the world over the past 20 years have all found that only a low percentage of the units tested had an output within 30% of that indicatd. In New Zealand, a survey carried out by the NRL in 1985 found that only 24% had an output, at the maximum setting, within + or - 20% of that indicated. The present performance Standard for new equipment (NZS 3200.2.5:1992) requires that the measured output should not deviate from that indicated by more than + or - 30 %. This may be tightened to + or - 20% in the next few years. Any calibration is only as good as the calibration equipment. Some force balances can be tested with small weights to simulate the force exerted by an ultrasound beam, but with others this is not possible. For such balances, testing may only be feasible with a calibrated source which could be used like a transfer standard. (author). 4 refs., 3 figs

  5. NVLAP calibration laboratory program

    Energy Technology Data Exchange (ETDEWEB)

    Cigler, J.L.

    1993-12-31

    This paper presents an overview of the progress up to April 1993 in the development of the Calibration Laboratories Accreditation Program within the framework of the National Voluntary Laboratory Accreditation Program (NVLAP) at the National Institute of Standards and Technology (NIST).

  6. NVLAP calibration laboratory program

    International Nuclear Information System (INIS)

    Cigler, J.L.

    1993-01-01

    This paper presents an overview of the progress up to April 1993 in the development of the Calibration Laboratories Accreditation Program within the framework of the National Voluntary Laboratory Accreditation Program (NVLAP) at the National Institute of Standards and Technology (NIST)

  7. Gamma ray calibration system

    International Nuclear Information System (INIS)

    Rosauer, P.J.; Flaherty, J.J.

    1981-01-01

    This invention is in the field of gamma ray inspection devices for tubular products and the like employing an improved calibrating block which prevents the sensing system from being overloaded when no tubular product is present, and also provides the operator with a means for visually detecting the presence of wall thicknesses which are less than a required minimum. (author)

  8. A TRMM-Calibrated Infrared Rainfall Algorithm Applied Over Brazil

    Science.gov (United States)

    Negri, A. J.; Xu, L.; Adler, R. F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The development of a satellite infrared technique for estimating convective and stratiform rainfall and its application in studying the diurnal variability of rainfall in Amazonia are presented. The Convective-Stratiform. Technique, calibrated by coincident, physically retrieved rain rates from the Tropical Rain Measuring Mission (TRMM) Microwave Imager (TMI), is applied during January to April 1999 over northern South America. The diurnal cycle of rainfall, as well as the division between convective and stratiform rainfall is presented. Results compare well (a one-hour lag) with the diurnal cycle derived from Tropical Ocean-Global Atmosphere (TOGA) radar-estimated rainfall in Rondonia. The satellite estimates reveal that the convective rain constitutes, in the mean, 24% of the rain area while accounting for 67% of the rain volume. The effects of geography (rivers, lakes, coasts) and topography on the diurnal cycle of convection are examined. In particular, the Amazon River, downstream of Manaus, is shown to both enhance early morning rainfall and inhibit afternoon convection. Monthly estimates from this technique, dubbed CST/TMI, are verified over a dense rain gage network in the state of Ceara, in northeast Brazil. The CST/TMI showed a high bias equal to +33% of the gage mean, indicating that possibly the TMI estimates alone are also high. The root mean square difference (after removal of the bias) equaled 36.6% of the gage mean. The correlation coefficient was 0.77 based on 72 station-months.

  9. Calibration of sensors for acoustic detection of neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Ardid, M; Bou-Cabo, M; Espinosa, V; Martinez-Mora, J; Camarena, F; Alba, J [Departament de Fisica Aplicada, E.P.S. Gandia, Universitat Politecnica de Valencia, Cra. Nazaret/Oliva S/N, E-46730 Gandia (Spain)

    2007-09-15

    Calibration of sensors is an important task for the acoustic detection of neutrinos. Different approaches have been tried and used (calibrated hydrophones, resistors, powerful lasers, light bulbs explosion, etc.) We propose some methods for calibration that can be used in both the lab and the telescope ('in situ'). In this paper, different studies following these methods and their results are reported. First, we describe the reciprocity calibration method for acoustic sensors. Since it is a simple method and calibrated hydrophones are not needed, this technique is accessible for any lab. Moreover, the technique could be used to calibrate the sensors of a neutrino telescope just by using themselves (reciprocally). A comparison of this technique using different kind of signals (MLS, TSP, tone bursts, white noise), and in different propagation conditions is presented. The limitations of the technique are shown, as well as some possibilities to overcome them. The second aspect treated is the obtaining of neutrinolike signals for calibration. Probably, the most convenient way to do it would be to generate these signals from transducers directly. Since transducers do not usually have a flat frequency response, distortion is produced, and neutrino-like signals could be difficult to achieve. We present some equalization techniques to offset this effect. In this sense, the use of inverse filter based in Mourjopoulos theory seems to be quite convenient.

  10. PLEIADES ABSOLUTE CALIBRATION : INFLIGHT CALIBRATION SITES AND METHODOLOGY

    Directory of Open Access Journals (Sweden)

    S. Lachérade

    2012-07-01

    Full Text Available In-flight calibration of space sensors once in orbit is a decisive step to be able to fulfil the mission objectives. This article presents the methods of the in-flight absolute calibration processed during the commissioning phase. Four In-flight calibration methods are used: absolute calibration, cross-calibration with reference sensors such as PARASOL or MERIS, multi-temporal monitoring and inter-bands calibration. These algorithms are based on acquisitions over natural targets such as African deserts, Antarctic sites, La Crau (Automatic calibration station and Oceans (Calibration over molecular scattering or also new extra-terrestrial sites such as the Moon and selected stars. After an overview of the instrument and a description of the calibration sites, it is pointed out how each method is able to address one or several aspects of the calibration. We focus on how these methods complete each other in their operational use, and how they help building a coherent set of information that addresses all aspects of in-orbit calibration. Finally, we present the perspectives that the high level of agility of PLEIADES offers for the improvement of its calibration and a better characterization of the calibration sites.

  11. Effects of line fiducial parameters and beamforming on ultrasound calibration.

    Science.gov (United States)

    Ameri, Golafsoun; Baxter, John S H; McLeod, A Jonathan; Peters, Terry M; Chen, Elvis C S

    2017-01-01

    Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration. It was shown that the FLE was reduced by 29% with synthetic transmit aperture imaging compared with conventional B-mode imaging in a Z-bar calibration, resulting in a 10% reduction of calibration error. In addition, an evaluation of a variety of calibration phantoms with different geometrical and material properties was performed. The phantoms included braided wire, plastic straws, and polyvinyl alcohol cryogel tubes with different diameters. It was shown that these properties have a significant effect on calibration error, which is a variable based on US beamforming techniques. These results would have important implications for calibration procedures and their feasibility in the context of image-guided procedures.

  12. Simple laser vision sensor calibration for surface profiling applications

    Science.gov (United States)

    Abu-Nabah, Bassam A.; ElSoussi, Adnane O.; Al Alami, Abed ElRahman K.

    2016-09-01

    Due to the relatively large structures in the Oil and Gas industry, original equipment manufacturers (OEMs) have been implementing custom-designed laser vision sensor (LVS) surface profiling systems as part of quality control in their manufacturing processes. The rough manufacturing environment and the continuous movement and misalignment of these custom-designed tools adversely affect the accuracy of laser-based vision surface profiling applications. Accordingly, Oil and Gas businesses have been raising the demand from the OEMs to implement practical and robust LVS calibration techniques prior to running any visual inspections. This effort introduces an LVS calibration technique representing a simplified version of two known calibration techniques, which are commonly implemented to obtain a calibrated LVS system for surface profiling applications. Both calibration techniques are implemented virtually and experimentally to scan simulated and three-dimensional (3D) printed features of known profiles, respectively. Scanned data is transformed from the camera frame to points in the world coordinate system and compared with the input profiles to validate the introduced calibration technique capability against the more complex approach and preliminarily assess the measurement technique for weld profiling applications. Moreover, the sensitivity to stand-off distances is analyzed to illustrate the practicality of the presented technique.

  13. Mercury CEM Calibration

    Energy Technology Data Exchange (ETDEWEB)

    John F. Schabron; Joseph F. Rovani; Susan S. Sorini

    2007-03-31

    The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005, requires that calibration of mercury continuous emissions monitors (CEMs) be performed with NIST-traceable standards. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The traceability protocol will be written by EPA. Traceability will be based on the actual analysis of the output of each calibration unit at several concentration levels ranging from about 2-40 ug/m{sup 3}, and this analysis will be directly traceable to analyses by NIST using isotope dilution inductively coupled plasma/mass spectrometry (ID ICP/MS) through a chain of analyses linking the calibration unit in the power plant to the NIST ID ICP/MS. Prior to this project, NIST did not provide a recommended mercury vapor pressure equation or list mercury vapor pressure in its vapor pressure database. The NIST Physical and Chemical Properties Division in Boulder, Colorado was subcontracted under this project to study the issue in detail and to recommend a mercury vapor pressure equation that the vendors of mercury vapor pressure calibration units can use to calculate the elemental mercury vapor concentration in an equilibrium chamber at a particular temperature. As part of this study, a preliminary evaluation of calibration units from five vendors was made. The work was performed by NIST in Gaithersburg, MD and Joe Rovani from WRI who traveled to NIST as a Visiting Scientist.

  14. Calibration of the NPL secondary standard radionuclide calibrator for the new 10R Schott, Type 1+ vials

    International Nuclear Information System (INIS)

    Baker, M.

    2005-01-01

    For many years, P6 vials have been used for the distribution of a wide range of diagnostic and therapeutic radioactive solutions. The activity measurements were performed in this geometry and, in time, the UK calibration system for nuclear medicine was based on this container as a standard. However, one major supplier of radiopharmaceuticals has replaced the P6 vial with the 10R Type 1+ Schott vial. As the dimensions of the new vial are diffe