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Sample records for automatic tube current

  1. Automatic Inspection of Nuclear-Reactor Tubes During Production and Processing, Using Eddy-Current Methods

    International Nuclear Information System (INIS)

    The possibilities of automatic and semi-automatic inspection of tubes using eddy-current methods are described. The paper deals in particular with modem processes, compared to the use of other non-destructive methods. The essence of the paper is that the methods discussed are ideal for objective automatic inspection. Not only are the known methods described, but certain new methods and their application to the detection of flaws in reactor tubes are discussed. (author)

  2. Extraction: a system for automatic eddy current diagnosis of steam generator tubes in nuclear power plants

    International Nuclear Information System (INIS)

    Improving speed and quality of Eddy Current non-destructive testing of steam generator tubes leads to automatize all processes that contribute to diagnosis. This paper describes how we use signal processing, pattern recognition and artificial intelligence to build a software package that is able to automatically provide an efficient diagnosis. (authors). 2 figs., 5 refs

  3. EXTRACSION: a system for automatic Eddy Current diagnosis of steam generator tubes in nuclear power plants

    International Nuclear Information System (INIS)

    Improving speed and quality of Eddy Current non-destructive testing of steam generator tubes leads to automation of all process that contribute to diagnosis. This paper describes how signal processing, pattern recognition and artificial and artificial intelligence are used to build a software package that is able to automatically provide an efficient diagnosis. (author)

  4. Relationships between patient size, dose and image noise under automatic tube current modulation systems

    International Nuclear Information System (INIS)

    Automatic tube current modulation (ATCM) systems are now used for the majority of CT scans. The principles of ATCM operation are different in CT scanners from different manufacturers. Toshiba and GE scanners base the current modulation on a target noise setting, while Philips and Siemens scanners use reference image and reference mAs concepts respectively. Knowledge of the relationships between patient size, dose and image noise are important for CT patient dose optimisation. In this study, the CT patient doses were surveyed for 14 CT scanners from four different CT scanner manufacturers. The patient cross sectional area, the tube current modulation and the image noise from the CT images were analysed using in-house software. The Toshiba and GE scanner results showed that noise levels are relatively constant but tube currents are dependent on patient size. As a result of this there is a wide range in tube current values across different patient sizes, and doses for large patients are significantly higher in these scanners. In contrast, in the Philips and Siemens scanners, tube currents are less dependent on patient size, the range in tube current is narrower, and the doses for larger patients are not as high. Image noise is more dependent on the patient size. (paper)

  5. An integrated automatic system for the eddy-current testing of the steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Hee Gon; Choi, Seong Su [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1995-12-31

    This research project was focused on automation of steam generator tubes inspection for nuclear power plants. ECT (Eddy Current Testing) inspection process in nuclear power plants is classified into 3 subprocesses such as signal acquisition process, signal evaluation process, and inspection planning and data management process. Having been automated individually, these processes were effectively integrated into an automatic inspection system, which was implemented in HP workstation with expert system developed (author). 25 refs., 80 figs.

  6. Comparison of different phantom designs for CT scanner automatic tube current modulation system tests

    International Nuclear Information System (INIS)

    Modern CT scanners modulate tube current during scans according to patient size, shape and attenuation. However, the ATCM (automatic tube current modulation) systems for different CT manufacturers work on different principles. Although the systems are used for the majority of patients and examinations, there is no standard phantom for routine quality control of CT scanner ATCM operation. The ideal phantom for testing these systems should be capable of evaluating how tube current and image quality as well as dose vary according to changes in patient size and shape. For this study, a conical phantom designed by ImPACT has been compared with two phantoms made from elliptical sections with varying dimensions. The concept of the designs is to reflect the ATCM performance for the varying shapes and dimensions along the length of the human body. The first phantom comprises five elliptical sections with a wide range of different dimensions and the second has three sections that are more similar in size. The phantoms have been used to test ATCM systems for Philips, Siemens, GE and Toshiba scanners. Although the results of the tube current modulation patterns were similar for all CT scanners, the abrupt changes in attenuation for the first sectional phantom provoked an abnormal ATCM response for the GE and Toshiba scanners. The second sectional phantom was developed from the results of the first, and was more effective for ATCM system testing and could be used for dose and image quality assessment in standard positions. However, the ImPACT conical phantom provided the best overall assessment of performance in terms of tube current modulations and noise pattern. (paper)

  7. Dose conversion coefficients for paediatric CT examinations with automatic tube current modulation

    International Nuclear Information System (INIS)

    A common dose-saving technique used in modern CT devices is automatic tube current modulation (TCM), which was originally designed to also reduce the dose in paediatric CT patients. In order to be able to deduce detailed organ doses of paediatric models, dose conversion coefficients normalized to CTDIvol for an eight-week-old baby and seven- and eight-year-old children have been computed accounting for TCM. The relative difference in organ dose conversion coefficients with and without TCM is for many organs and examinations less than 10%, but can in some cases amount up to 30%, e.g., for the thyroid in the chest CT of the seven-year-old child. Overall, the impact of TCM on the conversion coefficients increases with increasing age. Besides TCM, also the effect of collimation and tube voltage on organ dose conversion coefficients has been investigated. It could be shown that the normalization to CTDIvol leads to conversion coefficients that can in most cases be considered to be independent of collimation and tube voltage. (paper)

  8. Influence of CT automatic tube current modulation on uncertainty in effective dose

    International Nuclear Information System (INIS)

    Computed tomography (CT) scanners are equipped with automatic tube current modulation (ATCM) systems that adjust the current to compensate for variations in patient attenuation. CT dosimetry variables are not defined for ATCM situations and, thus, only the averaged values are displayed and analysed. The patient effective dose (E), which is derived from a weighted sum of organ equivalent doses, will be modified by the ATCM. Values for E for chest-abdomen-pelvis CT scans have been calculated using the ImPACT spreadsheet for patients on five CT scanners. Values for E resulting from the z-axis modulation under ATCM have been compared with results assessed using the same effective mAs values with constant tube currents. Mean values for E under ATCM were within ±10 % of those for fixed tube currents for all scanners. Cumulative dose distributions under ATCM have been simulated for two patient scans using single-slice dose profiles measured in elliptical and cylindrical phantoms on one scanner. Contributions to the effective dose from organs in the upper thorax under ATCM are 30-35 % lower for superficial tissues (e.g. breast) and 15-20 % lower for deeper organs (e.g. lungs). The effect on doses to organs in the abdomen depends on body shape, and they can be 10-22 % higher for larger patients. Results indicate that scan dosimetry parameters, dose-length product and effective mAs averaged over the whole scan can provide an assessment in terms of E that is sufficiently accurate to quantify relative risk for routine patient exposures under ATCM. (authors)

  9. Automatic tube current modulation for volume scan in a 320-detector row CT scanner

    International Nuclear Information System (INIS)

    The x-y plane combined with z-axis automatic tube current modulation (ATCM) technique is one of the most comprehensive approaches to CT dose reduction because the radiation dose is adjusted according to patient attenuation in three dimensions. The 320-detector row CT scanner has the widest scan range (16 cm) within one axial rotation and equips with volume scan ATCM (VS-ATCM) mode. Special attention is needed while utilizing VS-ATCM mode in CT acquisitions especially scanning different anatomical regions, such as neck and shoulder in a single volume. However, the mechanism of VS-ATCM of the 320-detector row CT scanner remains unclear. This study aims to evaluate the performance of VS-ATCM mode in a 320-detector row CT scanner. A phantom set consists of three simple-shaped phantoms was scanned with the VS-ATCM mode. A solid-state detector was inserted into the central position of the phantom set to measure the real-time dose profiles at seven positions within five scan volumes. The effective tube-current time product of each slice was recorded. The standard deviation of the CT numbers measured at each image slice was used as a noise measurement. The performance of helical scan ATCM (HS-ATCM) mode was in comparison of VS-ATCM mode. The results indicated that VS-ATCM mode can provide a less dose CT scanning to a patient but resulted in a higher image noise in comparison with those of HS-ATCM mode. In clinical practice, radiologists or radiological technologists should pay more attention on the volume position when using VS-ATCM mode for patient imaging. Our experience can be a reference to others for implementation of clinical practices. -- Highlights: •Real-time dose profiles were measured for volume-scan ATCM mode. •Comparison of tube current variation between volume- and helical-scan ATCM modes. •Comparison of image noise between volume- and helical-scan ATCM modes

  10. Size-based protocol optimization using automatic tube current modulation and automatic kV selection in computed tomography.

    Science.gov (United States)

    MacDougall, Robert D; Kleinman, Patricia L; Callahan, Michael J

    2016-01-01

    Size-based diagnostic reference ranges (DRRs) for contrast-enhanced pediatric abdominal computed tomography (CT) have been published in order to establish practical upper and lower limits of CTDI, DLP, and SSDE. Based on these DRRs, guidelines for establishing size-based SSDE target levels from the SSDE of a standard adult by applying a linear correction factor have been published and provide a great reference for dose optimization initiatives. The necessary step of designing manufacturer-specific CT protocols to achieve established SSDE targets is the responsibility of the Qualified Medical Physicist. The task is straightforward if fixed-mA protocols are used, however, more difficult when automatic exposure control (AEC) and automatic kV selection are considered. In such cases, the physicist must deduce the operation of AEC algorithms from technical documentation or through testing, using a wide range of phantom sizes. Our study presents the results of such testing using anthropomorphic phantoms ranging in size from the newborn to the obese adult. The effect of each user-controlled parameter was modeled for a single-manufacturer AEC algorithm (Siemens CARE Dose4D) and automatic kV selection algorithm (Siemens CARE kV). Based on the results presented in this study, a process for designing mA-modulated, pediatric abdominal CT protocols that achieve user-defined SSDE and kV targets is described. PMID:26894344

  11. INFLUENCE OF LOCALIZER AND SCAN DIRECTION ON THE DOSE-REDUCING EFFECT OF AUTOMATIC TUBE CURRENT MODULATION IN COMPUTED TOMOGRAPHY.

    Science.gov (United States)

    Franck, C; Bacher, K

    2016-06-01

    The purpose of this study was to investigate the influence of the localizer and scan direction on the dose-reducing efficacy of the automatic tube current modulation (ATCM) in computed tomography (CT). Craniocaudal and caudocranial chest CT scans, based on anterior-posterior (AP), posterior-anterior (PA), lateral (LAT) or dual AP/LAT localizers, of an anthropomorphic phantom containing thermoluminescent dosimeters (TLDs), were made on three Siemens systems. TLD readings were converted to lung and thyroid doses. A second dose estimation was performed based on Monte Carlo simulations. In addition, the ATCM behaviour of GE and Toshiba was evaluated based on AP, PA and LAT localizers. Compared with AP, tube currents of PA and AP/LAT scans were on average 20 % higher and 40 % lower, respectively, for the Siemens systems. Consequently, thyroid and lung doses increased with 60 % with a PA instead of an AP/LAT scan, with significant differences in image noise. Moreover, the thyroid dose halves by taking the scan in caudocranial direction. Noise values were not significantly different when changing scan direction. PMID:27056145

  12. Automatic exposure control in multichannel CT with tube current modulation to achieve a constant level of image noise: Experimental assessment on pediatric phantoms

    International Nuclear Information System (INIS)

    Automatic exposure control (AEC) systems have been developed by computed tomography (CT) manufacturers to improve the consistency of image quality among patients and to control the absorbed dose. Since a multichannel helical CT scan may easily increase individual radiation doses, this technical improvement is of special interest in children who are particularly sensitive to ionizing radiation, but little information is currently available regarding the precise performance of these systems on small patients. Our objective was to assess an AEC system on pediatric dose phantoms by studying the impact of phantom transmission and acquisition parameters on tube current modulation, on the resulting absorbed dose and on image quality. We used a four-channel CT scan working with a patient-size and z-axis-based AEC system designed to achieve a constant noise within the reconstructed images by automatically adjusting the tube current during acquisition. The study was performed with six cylindrical poly(methylmethacrylate) (PMMA) phantoms of variable diameters (10-32 cm) and one 5 years of age equivalent pediatric anthropomorphic phantom. After a single scan projection radiograph (SPR), helical acquisitions were performed and images were reconstructed with a standard convolution kernel. Tube current modulation was studied with variable SPR settings (tube angle, mA, kVp) and helical parameters (6-20 HU noise indices, 80-140 kVp tube potential, 0.8-4 s. tube rotation time, 5-20 mm x-ray beam thickness, 0.75-1.5 pitch, 1.25-10 mm image thickness, variable acquisition, and reconstruction fields of view). CT dose indices (CTDIvol) were measured, and the image quality criterion used was the standard deviation of the CT number measured in reconstructed images of PMMA material. Observed tube current levels were compared to the expected values from Brooks and Di Chiro's [R.A. Brooks and G.D. Chiro, Med. Phys. 3, 237-240 (1976)] model and calculated values (product of a reference value

  13. Iterative reconstruction and individualized automatic tube current selection reduce radiation dose while maintaining image quality in 320-multidetector computed tomography coronary angiography

    International Nuclear Information System (INIS)

    Aim: To assess the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualized automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA). Materials and methods: In a single-centre cohort study, 942 patients underwent electrocardiogram-gated CTCA using a 320-multidetector CT system. Images from group 1 (n = 228) were reconstructed with a filtered back projection algorithm (Quantum Denoising Software, QDS+). Iterative reconstruction was used for group 2 (AIDR, n = 379) and group 3 (AIDR3D, n = 335). Tube current was selected based on body mass index (BMI) for groups 1 and 2, and selected automatically based on scout image attenuation for group 3. Subjective image quality was graded on a four-point scale (1 = excellent, 4 = non-diagnostic). Results: There were no differences in age (p = 0.975), body mass index (p = 0.435), or heart rate (p = 0.746) between the groups. Image quality improved with iterative reconstruction and automatic tube current selection [1.3 (95% confidence intervals (CI): 1.2–1.4), 1.2 (1.1–1.2) and 1.1 (1–1.2) respectively; p < 0.001] and radiation dose decreased [274 (260–290), 242 (230–253) and 168 (156–180) mGy cm, respectively; p < 0.001]. Conclusion: The application of the latest iterative reconstruction algorithm and individualized automatic tube current selection can substantially reduce radiation dose whilst improving image quality in CTCA

  14. Investigation of the influence of image reconstruction filter and scan parameters on operation of automatic tube current modulation systems for different CT scanners

    International Nuclear Information System (INIS)

    Variation in the user selected CT scanning parameters under automatic tube current modulation (ATCM) between hospitals has a substantial influence on the radiation doses and image quality for patients. The aim of this study was to investigate the effect of changing image reconstruction filter and scan parameter settings on tube current, dose and image quality for various CT scanners operating under ATCM. The scan parameters varied were pitch factor, rotation time, collimator configuration, kVp, image thickness and image filter convolution (FC) used for reconstruction. The Toshiba scanner varies the tube current to achieve a set target noise. Changes in the FC setting and image thickness for the first reconstruction were the major factors affecting patient dose. A two-step change in FC from smoother to sharper filters doubles the dose, but is counterbalanced by an improvement in spatial resolution. In contrast, Philips and Siemens scanners maintained tube current values similar to those for a reference image and patient, and the tube current only varied slightly for changes in individual CT scan parameters. The selection of a sharp filter increased the image noise, while use of iDose iterative reconstruction reduced the noise. Since the principles used by CT manufacturers for ATCM vary, it is important that parameters which affect patient dose and image quality for each scanner are made clear to operator to aid in optimisation. (authors)

  15. TH-C-18A-01: Is Automatic Tube Current Modulation Still Necessary with Statistical Iterative Reconstruction?

    International Nuclear Information System (INIS)

    Purpose: Automatic tube current modulation (TCM) has been widely used in modern multi-detector CT to reduce noise spatial nonuniformity and streaks to improve dose efficiency. With the advent of statistical iterative reconstruction (SIR), it is expected that the importance of TCM may diminish, since SIR incorporates statistical weighting factors to reduce the negative influence of photon-starved rays. The purpose of this work is to address the following questions: Does SIR offer the same benefits as TCM? If yes, are there still any clinical benefits to using TCM? Methods: An anthropomorphic CIRS chest phantom was scanned using a state-of-the-art clinical CT system equipped with an SIR engine (Veo™, GE Healthcare). The phantom was first scanned with TCM using a routine protocol and a low-dose (LD) protocol. It was then scanned without TCM using the same protocols. For each acquisition, both FBP and Veo reconstructions were performed. All scans were repeated 50 times to generate an image ensemble from which noise spatial nonuniformity (NSN) and streak artifact levels were quantified. Monte-Carlo experiments were performed to estimate skin dose. Results: For FBP, noise streaks were reduced by 4% using TCM for both routine and LD scans. NSN values were actually slightly higher with TCM (0.25) than without TCM (0.24) for both routine and LD scans. In contrast, for Veo, noise streaks became negligible (<1%) with or without TCM for both routine and LD scans, and the NSN was reduced to 0.10 (low dose) or 0.08 (routine). The overall skin dose was 2% lower at the shoulders and more uniformly distributed across the skin without TCM. Conclusion: SIR without TCM offers superior reduction in noise nonuniformity and streaks relative to FBP with TCM. For some clinical applications in which skin dose may be a concern, SIR without TCM may be a better option. K. Li, W. Zhao, D. Gomez-Cardona: Nothing to disclose; G.-H. Chen: Research funded, General Electric Company Research funded

  16. Method for Automatic Tube Current Selection for Obtaining a Consistent Image Quality and Dose Optimization in a Cardiac Multidetector CT

    OpenAIRE

    Qi, Weiwei; Li, Jianying; Du, Xiangke

    2009-01-01

    Objective To evaluate a quantitative method for individually adjusting the tube current to obtain images with consistent noise in electrocardiogram (ECG)-gated CT cardiac scans. Materials and Methods The image noise from timing bolus and cardiac CT scans of 80 patients (Group A) who underwent a 64-row multidetector (MD) CT cardiac examination with patient-independent scan parameters were analyzed. A formula was established using the noise correlation between the timing bolus and cardiac scans...

  17. Method for Automatic Tube Current Selection for Obtaining a Consistent Image Quality and Dose Optimization in a Cardiac Multidetector CT

    International Nuclear Information System (INIS)

    To evaluate a quantitative method for individually adjusting the tube current to obtain images with consistent noise in electrocardiogram (ECG)-gated CT cardiac scans. The image noise from timing bolus and cardiac CT scans of 80 patients (Group A) who underwent a 64-row multidetector (MD) CT cardiac examination with patient-independent scan parameters were analyzed. A formula was established using the noise correlation between the timing bolus and cardiac scans. This formula was used to predict the required tube current to obtain the desired cardiac CT image noise based on the timing bolus noise measurement. Subsequently, 80 additional cardiac patients (Group B) were scanned with individually adjusted tube currents using an established formula to evaluate its ability to obtain accurate and consistent image noise across the patient population. Image quality was evaluated using score scale of 1 to 5 with a score of 3 or higher being clinically acceptable. Using the formula, we obtained an average CT image noise of 28.55 Hounsfield unit (HU), with a standard deviation of only 1.7 HU, as opposed to a target value of 28 HU. Image quality scores were 4.03 and 4.27 for images in Groups A and B, respectively, and there was no statistical difference between the image quality scores between the two groups. However, the average CT dose index (CTDIvol) was 30% lower for Group B. Adjusting the tube current based on timing bolus scans may provide a consistent image quality and dose optimization for cardiac patients of various body mass index values

  18. Combined use of automatic tube voltage selection and current modulation with iterative reconstruction for CT evaluation of small hypervascular hepatocellular carcinomas: Effect on lesion conspicuity and image quality

    International Nuclear Information System (INIS)

    To assess the lesion conspicuity and image quality in CT evaluation of small (< or = 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction. One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups. Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022). CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction.

  19. Automatic exposure control in CT: the effect of patient size, anatomical region and prescribed modulation strength on tube current and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, Antonios E. [University Hospital of Heraklion, Department of Medical Physics, Stavrakia, P.O. Box 1352, Heraklion, Crete (Greece); Perisinakis, Kostas; Damilakis, John [University of Crete, Faculty of Medicine, Department of Medical Physics, P.O. Box 2208, Heraklion, Crete (Greece)

    2014-10-15

    To study the effect of patient size, body region and modulation strength on tube current and image quality on CT examinations that use automatic tube current modulation (ATCM). Ten physical anthropomorphic phantoms that simulate an individual as neonate, 1-, 5-, 10-year-old and adult at various body habitus were employed. CT acquisition of head, neck, thorax and abdomen/pelvis was performed with ATCM activated at weak, average and strong modulation strength. The mean modulated mAs (mAs{sub mod}) values were recorded. Image noise was measured at selected anatomical sites. The mAs{sub mod} recorded for neonate compared to 10-year-old increased by 30 %, 14 %, 6 % and 53 % for head, neck, thorax and abdomen/pelvis, respectively, (P < 0.05). The mAs{sub mod} was lower than the preselected mAs with the exception of the 10-year-old phantom. In paediatric and adult phantoms, the mAs{sub mod} ranged from 44 and 53 for weak to 117 and 93 for strong modulation strength, respectively. At the same exposure parameters image noise increased with body size (P < 0.05). The ATCM system studied here may affect dose differently for different patient habitus. Dose may decrease for overweight adults but increase for children older than 5 years old. Care should be taken when implementing ATCM protocols to ensure that image quality is maintained. circle ATCM efficiency is related to the size of the patient's body. (orig.)

  20. A study of CT dose distribution in an elliptical phantom and the influence of automatic tube current modulation in the x-y plane.

    Science.gov (United States)

    Sookpeng, S; Martin, C J; Gentle, D J

    2013-06-01

    Computed tomography (CT) performance assessments relating to patient dose to the body are made conventionally in 320 mm diameter cylindrical acrylic phantoms. The cross section of the human trunk is closer to an ellipse and automatic tube current modulation (ATCM) systems adjust the exposure level with orientation in the x-y plane, changing the dose distribution within the body. This study has investigated differences in the distributions of dose within a standard cylindrical body phantom and an elliptical dosimetry phantom for Toshiba, General Electric and Philips CT scanners, and recorded changes with the application of the ATCM. Single slice dose profiles have been recorded within the phantoms using Gafchromic film. CT dose indices along 100 mm lengths have been calculated and data sets combined to simulate helical scans, from which values for cumulative doses have been derived. The doses in the centre of the elliptical phantom are 70-100% larger than for the cylindrical one and in the anterior are around 20-40% larger, while the doses in the lateral positions are similar for the two phantom shapes. The differences between the anterior and lateral doses were larger for the Toshiba scanner and this is thought to be linked to the narrower profile of the beam produced by the bow-tie filter. When the ATCM mode for the Toshiba scanner is implemented, the doses in the anterior and posterior positions are reduced preferentially, bringing them closer to the doses in the lateral positions. PMID:23676349

  1. Ionization tube simmer current circuit

    Science.gov (United States)

    Steinkraus, Jr., Robert F.

    1994-01-01

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

  2. Eddy current inspection of tubing

    International Nuclear Information System (INIS)

    The Experimental research work carried out to develop a Eddy current testing equipment is described. Search coils with ferrite or air cores were used and the obtained results are discussed. Valuable information was gained from a improved channel in which a direct measure of the defect and the reference signal phase difference is obtained. Artificial defect used to evaluate resolution and sensitivity were produced by electro-machining and mechanical means. Finned SAP tubing was tested in a routine basis with the described equipment and the results plotted. Basic and theoretical considerations on the Eddy current testing technique are given in the last section of this report. (Author)

  3. HIGH CURRENT COAXIAL PHOTOMULTIPLIER TUBE

    Science.gov (United States)

    Glass, N.W.

    1960-01-19

    A medium-gain photomultiplier tube having high current output, fast rise- time, and matched output impedance was developed. The photomultiplier tube comprises an elongated cylindrical envelope, a cylindrical anode supported at the axis of the envelope, a plurality of elongated spaced opaque areas on the envelope, and a plurality of light admitting windows. A photo-cathode is supported adjacent to each of the windows, and a plurality of secondary emissive dynodes are arranged in two types of radial arrays which are alternately positioned to fill the annular space between the anode and the envelope. The dynodes are in an array being radially staggered with respect to the dynodes in the adjacent array, the dynodes each having a portion arranged at an angle with respect to the electron path, such that electrons emitted by each cathode undergo multiplication upon impingement on a dynode and redirected flight to the next adjacent dynode.

  4. Eddy current signal comparison for tube identification

    Science.gov (United States)

    Glass, S. W.; Vojvodic, R.

    2015-03-01

    Inspection of nuclear power plant steam generator tubes is required to justify continued safe plant operation. The steam generators consist of thousands of tubes with nominal diameters of 15 to 22mm, approximately 1mm wall thickness, and 20 to 30m in length. The tubes are inspected by passing an eddy current probe through the tubes from tube end to tube end. It is critical to know exactly which tube identification (row and column) is associated with each tube's data. This is controlled by a precision manipulator that provides the tube ID to the eddy current system. Historically there have been some instances where the manipulator incorrectly reported the tube ID. This can have serious consequences including lack of inspection of a tube, or if a pluggable indication is detected, the tube is likely to be mis-plugged thereby risking a primary to secondary leak.

  5. Eddy current signal comparison for tube identification

    International Nuclear Information System (INIS)

    Inspection of nuclear power plant steam generator tubes is required to justify continued safe plant operation. The steam generators consist of thousands of tubes with nominal diameters of 15 to 22mm, approximately 1mm wall thickness, and 20 to 30m in length. The tubes are inspected by passing an eddy current probe through the tubes from tube end to tube end. It is critical to know exactly which tube identification (row and column) is associated with each tube's data. This is controlled by a precision manipulator that provides the tube ID to the eddy current system. Historically there have been some instances where the manipulator incorrectly reported the tube ID. This can have serious consequences including lack of inspection of a tube, or if a pluggable indication is detected, the tube is likely to be mis-plugged thereby risking a primary to secondary leak

  6. Eddy current tube testing unit

    International Nuclear Information System (INIS)

    The unit described can check a wide variety of tubes in quick succession and its modular design gives it a high degree of versability. Suitably defined working conditions and specific fittings enable most of the faults encountered in the manufacture of a tube to be detected. By appropriate means of selection based on signal amplitude, phase and frequency analyses it is possible to adapt selection criteria to the seriousness of the different categories of defect

  7. The TS 600: automatic control system for eddy currents

    International Nuclear Information System (INIS)

    In the scope of fabrication and in service inspection of the PWR steam generator tubing bendle, FRAMATOME developed an automatic Eddy Current testing system: TS600. Based on a mini-computer, TS600 allows to digitize, to store and to process data in various ways, so it is possible to perform several kinds of inspection: conventional inservice inspection, roll area profilometry...... TS600 can also be used to develop new methods of examination

  8. Development of automatic inspection robot for boiler tubes using EMAT

    International Nuclear Information System (INIS)

    In this study, a mobile robotic system using NDT (Non-destructive testing) method is developed for automatic diagnosis of the boiler tubes. The developed mobile robot crawls the surface of the tubes and detects in-pipe defects such as pinholes, cracks and thickness reduction by corrosion and/or erosion using EMAT (Electro-magnetic Acoustic Transducer) sensors. Automation of fault detection by means of mobile robotic systems for large-scale structures helps to prevent significant troubles without danger of human beings under harmful environment. In this study a preliminary result with guided wave inspection for defect detection is shown.

  9. Automatic integrated testing bench for tubes in translation

    International Nuclear Information System (INIS)

    All the nondestructive tests required for receiving the cladding tubes intended for fast nuclear reactor are integrated on this bench: quality control by eddy currents and ultra-sounds, thickness and (inner and outer) diameter measurement. The linear displacement of the tube allows very high rates to be attained

  10. Circle Points Discharge Tube Current Controller

    Institute of Scientific and Technical Information of China (English)

    Meng Jinjia; Meng Lisheng

    2005-01-01

    Circle points discharge tube current controller is a new type device to limit theoutput of high voltage discharge current. Circle points uniform corona discharge to form airionization current in the discharge tube. On the outside, even if the discharge electrode is sparkdischarging or the two discharge electrodes are short circuited, the air ionization current in the tuberemains within a stable range, and there is no spark discharge. In this case, when the dischargecurrent only increases slightly, the requirement to limited current is obtained. By installing thecontroller at a discharge pole with a small power but high voltage supply, we can realize the shiftbetween the continuous spark line discharge and corona discharge. This provides a new simpledevice for spark discharge research and is a supplement to the Townsend discharge experiment.

  11. Automatic measuring system of zirconium thickness for zirconium liner cladding tubes

    International Nuclear Information System (INIS)

    An automatic measuring system of pure zirconium liner thickness for Zirconium-Zircaloy cladding tubes has been successfully developed. The system consists of three parts. An ultrasonic thickness measuring method for mother tubes before cold rolling; an electromagnetic thickness measuring method for the manufactured tubes, and, an image processing method for the cross sectional view of the manufactured cut tube samples

  12. Tube current reduction in pediatric non-ECG-gated heart CT by combined tube current modulation

    International Nuclear Information System (INIS)

    Dose reduction by combined tube current modulation has not been evaluated in pediatric low-dose CT. This study was performed to evaluate tube current reduction in non-ECG-gated heart CT angiography in children by combined tube current modulation, and to assess the effects of body weight, age, sex, and scan direction on tube current reduction. From September 2004 to January 2005, non-ECG-gated heart CT examinations were performed with combined tube current modulation in 50 children (median age 1 year, range 1 month to 16 years; M/F 29/21) with congenital heart disease. Sixteen-slice spiral CT studies were obtained using a weight-based low-dose protocol (80 kVp, 50-160 effective mA). CT scans were obtained in the craniocaudal direction when leg veins (n=36) were used for IV injection of contrast agent and in the caudocranial direction when arm veins (n=13) were used. In one child who underwent a Fontan operation, both arm and leg veins were used. We calculated tube current reduction by combined tube current modulation and evaluated the effects of body weight, age, sex, and scan technique on tube current reduction. The quality of CT angiography images was visually evaluated by an experienced pediatric radiologist. Overall tube current reduction by combined tube current modulation was 15.8±11.1%. The reduction was variable among five body weight groups (9.3±7.9% for <4.9 kg, 14.3±9.3% for 5.0-9.9 kg, 16.4±12.5% for 10.0-19.9 kg, 25.8±9.8% for 20.0-39.9 kg, 15.9±12.7% for 40.0-59.9 kg) and was significantly different among the five groups (P=0.017). When eight children in the 40.0-59.9-kg group were excluded, age showed a significant positive correlation with tube current reduction (γ=0.4, P=0.003). There was no significant difference in tube current reduction between boys and girls. Tube current reduction was significantly greater for the caudocranial scan (21.2±9.2%) than for the craniocaudal scan (14.2±11.3%) (P=0.049). All CT angiography images were of

  13. Eddy-Current Detection of Cracks in Tubes

    Science.gov (United States)

    Parent, R.; Kettering, D.

    1987-01-01

    Nondestructive device tests narrow, sharply-bent metal tubes. Eddycurrent probe detects incipient cracks inside small metal tubes. Tube-centering device consisting of pair of opposed bars ensures tube centered on eddy-current coil. Probe moves along length of bent tube to inspect repeatably for cracks. Compatible with tubes of different cross sections, oval, flattened, square, rectangular,or irregular. Adapts for inspecting formed tubes in petrochemical, automotive, nuclear, and medical equipment.

  14. Thin tube testing by eddy currents

    International Nuclear Information System (INIS)

    It is often necessary to define test conditions in eddy current testing, in consequence rules and laws allowing a rapid choice of these conditions are welcome. The similarity law, given by Forster, using the reduced frequency f/fg, allows extrapolation of results from an object to one another, if these two objects are similar (i.e. all their dimensions are proportional). In a particular case, often met, a law going further is given to describe, in a sole way, eddy current behaviour using the reduced frequency in all thin tubes (internal to external diameter ratio between 0.85 to 1). For instance working at f/fe=2 defines the same verification leading to identical results, whatever the nature, the diameter or the thickness may be, if the tubes are thin. A diagram is given and a slide-rule, based on this principle, has been realized

  15. Advanced Eddy current NDE steam generator tubing

    International Nuclear Information System (INIS)

    As part of a multifaceted project on steam generator integrity funded by the U.S. Nuclear Regulatory Commission, Argonne National Laboratory is carrying out research on the reliability of nondestructive evaluation (NDE). A particular area of interest is the impact of advanced eddy current (EC) NDE technology. This paper presents an overview of work that supports this effort in the areas of numerical electromagnetic (EM) modeling, data analysis, signal processing, and visualization of EC inspection results. Finite-element modeling has been utilized to study conventional and emerging EC probe designs. This research is aimed at determining probe responses to flaw morphologies of current interest. Application of signal processing and automated data analysis algorithms has also been addressed. Efforts have focused on assessment of frequency and spatial domain filters and implementation of more effective data analysis and display methods. Data analysis studies have dealt with implementation of linear and nonlinear multivariate models to relate EC inspection parameters to steam generator tubing defect size and structural integrity. Various signal enhancement and visualization schemes are also being evaluated and will serve as integral parts of computer-aided data analysis algorithms. Results from this research will ultimately be substantiated through testing on laboratory-grown and in-service-degraded tubes

  16. Automatic ultrasonic system for flaw detection and dimensional measurement of precision tubes

    International Nuclear Information System (INIS)

    This paper describes a system, which is installed at Nuclear Fuel Complex, Hyderabad. It is a tube rotation fixed probe type of system designed for fully automatic operation at high speed using immersion technique for ultrasonic flaw detection and dimensional measurement of precision of zirconium alloy seamless tubes used in fuel bundles for nuclear reactors

  17. Automatic all position welding for horizontally fixed tubes by tungsten inert gas arc welding method

    International Nuclear Information System (INIS)

    The welding of fixed tubes is mostly all position welding in restricted places, accordingly much skill is required. The automation of welding is necessary because of the requirement for the reliability of welded joints, the difficulty of securing skilled workers, and welding quality. The development and production of the automatic welders for TIG welding of tubes have been carried out by Mitsubishi Electric Corp., and the application to various purposes was attempted. The TIG welding for the automatic welding of tubes is advantageous, because backside bead can be formed stably, spatter does not arise, welding is stable for every metal, and the mechanism of the automatic welders is simple. But it is not suitable for the welding of zinc-plated tubes, and the rate of deposition is relatively small. It is applied to the welding of boiler tubes, nuclear energy equipments and pipings, chemical equipments and pipings, and aluminum pipings. The specifications and the construction of the TIG tube welders are shown. The preparation of joints and the control of welding conditions are important for guaranteeing the welding results in automatic welding, therefore sufficient consultation with welder makers about these points is required. The welding defects apt to arise are the bad form of backside beads, blowholes, and the insufficient melting of intermediate layers, and the countermeasures to them must be taken. (Kako, I.)

  18. Automatic measuring system of zirconium thickness for zirconium liner cladding tubes

    International Nuclear Information System (INIS)

    An automatic system of pure zirconium liner thickness for zirconium-zircaloy cladding tubes has been successfully developed. The system consists of three parts. (1) An ultrasonic thickness measuring method for mother tubes before cold rolling. (2) An electromagnetic thickness measuring method for the manufactured tubes. (3) An image processing method for the cross sectional view of the manufactured cut tube samples. In Japanese nuclear industry, zirconium-zircaloy cladding tubes have been tested in order to realize load following operation in the atomic power plant. In order to provide for the practical use in the near future, Sumitomo Metal Industries, Ltd. has been studied and established the practical manufacturing process of the zirconium liner cladding tubes. The zirconium-liner cladding tube is a duplex tube comprising an inner layer of pure zirconium bonded to zircaloy metallurgically. The thickness of the pure zirconium is about 10 % of the total wall thickness. Several types of the automatic thickness measuring methods have been investigated instead of the usual microscopic viewing method in which the liner thickness is measured by the microscopic cross sectional view of the cut tube samples

  19. Eddy-current tests on operational evaluation of steam generator tubes in nuclear power plants

    International Nuclear Information System (INIS)

    This paper presents a worldwide research on the technical and economical impacts due to failure in tube bundles of nuclear power plant steam generators. An Eddy current non destructive test using Foucault currents for the inspection and failure detection on the tubes, and also the main type of defects. The paper also presents the signals generated by a Zetec MIZ-40 test equipment. This paper also presents a brief description of an automatic system for data analysis which is under development by using a fuzzy logic and artificial intelligence

  20. Prediction of extubation outcome: a randomised, controlled trial with automatic tube compensation vs. pressure support ventilation

    OpenAIRE

    Cohen, Jonathan; Shapiro, Maury; Grozovski, Elad; Fox, Ben; Lev, Shaul; Singer, Pierre

    2009-01-01

    Introduction Tolerance of a spontaneous breathing trial is an evidence-based strategy to predict successful weaning from mechanical ventilation. Some patients may not tolerate the trial because of the respiratory load imposed by the endotracheal tube, so varying levels of respiratory support are widely used during the trial. Automatic tube compensation (ATC), specifically developed to overcome the imposed work of breathing because of artificial airways, appears ideally suited for the weaning ...

  1. Multifrequency eddy current testing of helical tubes of steam generators

    International Nuclear Information System (INIS)

    In the event of a water-sodium reaction in a steam-generator of a fast breeder reactor, it is necessary to test the tubes close to the leak to evaluate the damage. In SUPERPHENIX, the tubes are about 100m long and are coiled on a dead body. This report describes the equipment and the technic to test such tubes with multifrequency eddy current technics

  2. Automatic selection of tube potential for radiation dose reduction in CT: A general strategy

    International Nuclear Information System (INIS)

    Purpose: To optimize radiation dose efficiency in CT while maintaining image quality, it is important to select the optimal tube potential. The selection of optimal tube potential, however, is highly dependent on patient size and diagnostic task. The purpose of this work was to develop a general strategy that allows for automatic tube potential selection for each individual patient and each diagnostic task. Methods: The authors propose a general strategy that allows automatic adaptation of the tube potential as a function of patient size and diagnostic task, using a novel index of image quality, ''iodine contrast to noise ratio with a noise constraint (iCNRNC),'' to characterize the different image quality requirements by various clinical applications. The relative dose factor (RDF) at each tube potential to achieve a target image quality was then determined as a function of patient size and the noise constraint parameter. A workflow was developed to automatically identify the optimal tube potential that is both dose efficient and practically feasible, incorporating patient size and diagnostic task. An experimental study using a series of semianthropomorphic thoracic phantoms was used to demonstrate how the proposed general strategy can be implemented and how the radiation dose reduction achievable by the tube potential selection depends on phantom sizes and noise constraint parameters. Results: The proposed strategy provides a flexible and quantitative way to select the optimal tube potential based on the patient size and diagnostic task. The noise constraint parameter α can be adapted for different clinical applications. For example, α=1 for noncontrast routine exams; α=1.1-1.25 for contrast-enhanced routine exams; and α=1.5-2.0 for CT angiography. For the five thoracic phantoms in the experiment, when α=1, the optimal tube potentials were 80, 100, 100, 120, 120, respectively. The corresponding RDFs (relative to 120 kV) were 78.0%, 90.9%, 95.2%, 100%, and

  3. Eddy current detection of corrosion damage in heat exchanger tubes

    International Nuclear Information System (INIS)

    Eddy current is often the most effective nondestructive test method available for in-service inspection of small bore tubing in heat exchangers. The basic principles, advantages and shortcomings of the technique are outlined. Typical eddy current indications from corrosion-related defects such as stress corrosion cracks, pitting and tube denting under support plates are presented. Eddy current signals from features such as magnetite deposits and ferromagnetic inclusions which might be mistaken for defects are also discussed. (auth)

  4. Automatic analysis of signals during Eddy currents controls

    International Nuclear Information System (INIS)

    A method and the corresponding instrument have been developed for automatic analysis of Eddy currents testing signals. This apparatus enables at the same time the analysis, every 2 milliseconds, of two signals at two different frequencies. It can be used either on line with an Eddy Current testing instrument or with a magnetic tape recorder

  5. Remote field eddy current testing of ferromagnetic tubes

    International Nuclear Information System (INIS)

    In order to test ferromagnetic tubes using internal probes, Intercontrole and the CEA have carried out theoretical and experimental works and developed a method to adapt the Remote Field Eddy Current technique which has been known and used for 30 years now. This document briefly recalls the basic principles of the Remote Field Eddy Current technique, the various steps of the works carried out and mainly describes examples of field inspection of ferromagnetic tubes and pipes

  6. GTSP, automatic ultrasonic inspection of Guide Tube Support Pin in nuclear power plants

    International Nuclear Information System (INIS)

    1 - Description of program or function: GTSP Visitor is a program for automatic detection of known object's position in video frames. It is especially designed for automatic ultrasonic inspection of guide tube support pin (GTSP) in nuclear power plant. 2 - Methods: A GTSP and its position are detected by two-step matched filter algorithm. In first step, a video frame including GTSPs are transformed by DFT. DFTed image is multiplied by matched filter, made from a guide tube image, in frequency domain for estimate Guide Tube center position. Guide Tube areas around estimated center position are erased (pixel values of image are filled with zeros). In next step, image whose guide tube areas were erased is processed as described above but using a different matched filter made from a support pin?s image. Then the positions of two GTSPs are estimated and their orientation is estimated too. Finally its position and orientations are used for control the robot toward the desired position. 3 - Restrictions on the complexity of the problem: Robot control is out of the scope of this program. OpenCV and compatible camera are necessary

  7. Eddy current inspection of mildly ferromagnetic tubing

    International Nuclear Information System (INIS)

    The past decade has seen the development of eddy current probes for inspection of the mildly ferromagnetic alloy Monel 400. Due to the rapid advances in permanent magnet technology similar probes have been upgraded to magnetically saturate, and hence inspect, the duplex stainless steel Sandvik 3RE60, which has saturation induction more than twice that of Monel 400. Prototypes of these probes have been tested in three ways: saturation capability, quality of typical eddy current data, and ability to eliminate permeability induced signals. Successful laboratory testing, potential applications, and limitations of these type probes are discussed

  8. Eddy current inspection of mildly ferromagnetic tubing

    International Nuclear Information System (INIS)

    The past decade has seen the development of eddy current probes for inspection of the mildly ferro-magnetic alloy Monel 400. Due to the rapid advances in permanent magnet technology similar probes have been upgraded to magnetically saturate, and hence inspect, the duplex stainless steel Sandvik 3RE60, which has saturation induction more than twice that of Monel 400. Prototypes of these probes have been tested in three ways: saturation capability, quality of typical eddy current data, and ability to eliminate permeability induced signals. Successful laboratory testing, potential applications, and limitations of these type probes are discussed

  9. Performance demonstration requirements for eddy current steam generator tube inspection

    International Nuclear Information System (INIS)

    This paper describes the methodology used for developing performance demonstration tests for steam generator tube eddy current (ET) inspection systems. The methodology is based on statistical design principles. Implementation of a performance demonstration test based on these design principles will help to ensure that field inspection systems have a high probability of detecting and correctly sizing tube degradation. The technical basis for the ET system performance thresholds is presented. Probability of detection and flaw sizing tests are described

  10. Testing and analysis of tube voltage and tube current in the radiation generator for mammography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hong Ryang; Hong, Dong Hee [Dept. of Health Care, Hanseo University, Seosan (Korea, Republic of); Han, Beom Hui [Dept. of Radiological Science, Seonam University, Namwon (Korea, Republic of)

    2014-03-15

    Breast shooting performance management and quality control of the generator is applied to the amount of current IEC(International Electrotechnical Commission) 60601-2-45 tube voltage and tube current are based on standards that were proposed in the analysis of the test results were as follows. Tube voltage according to the value of the standard deviation by year of manufacture from 2001 to 2010 as a 42-3.15 showed the most significant, according to the year of manufacture by tube amperage value of the standard deviation to 6.38 in the pre-2000 showed the most significant , manufactured after 2011 the standard deviation of the devices, the PAE(Percent Average Error) was relatively low. This latest generation device was manufactured in the breast of the tube voltage and tube diagnosed shooting the correct amount of current to maintain the performance that can be seen. The results of this study as the basis for radiography diagnosed breast caused by using the device's performance and maintain quality control, so the current Food and Drug Administration 'about the safety of diagnostic radiation generator rule' specified in the test cycle during three years of self-inspection radiation on a radiation generating device ensure safety and performance of the device using a coherent X-ray(constancy) by two ultimately able to keep the radiation dose to the public to reduce the expected effect is expected.

  11. Testing and analysis of tube voltage and tube current in the radiation generator for mammography

    International Nuclear Information System (INIS)

    Breast shooting performance management and quality control of the generator is applied to the amount of current IEC(International Electrotechnical Commission) 60601-2-45 tube voltage and tube current are based on standards that were proposed in the analysis of the test results were as follows. Tube voltage according to the value of the standard deviation by year of manufacture from 2001 to 2010 as a 42-3.15 showed the most significant, according to the year of manufacture by tube amperage value of the standard deviation to 6.38 in the pre-2000 showed the most significant , manufactured after 2011 the standard deviation of the devices, the PAE(Percent Average Error) was relatively low. This latest generation device was manufactured in the breast of the tube voltage and tube diagnosed shooting the correct amount of current to maintain the performance that can be seen. The results of this study as the basis for radiography diagnosed breast caused by using the device's performance and maintain quality control, so the current Food and Drug Administration 'about the safety of diagnostic radiation generator rule' specified in the test cycle during three years of self-inspection radiation on a radiation generating device ensure safety and performance of the device using a coherent X-ray(constancy) by two ultimately able to keep the radiation dose to the public to reduce the expected effect is expected

  12. Automatic system for measuring the zirconium liner and Zircaloy-2 thickness of zirconium liner tubes

    International Nuclear Information System (INIS)

    This paper reports on an automatic system to measure the zirconium liner thickness and Zircaloy-2 thickness of Zircaloy tubes with a zirconium liner for nuclear reactors. This system uses an electromagnetic probe connected to a data processing unit for measuring the liner thickness, an ultrasonic inspection system for measuring the wall-thickness, and a computer for calculating the Zircaloy-2 thickness from the liner thickness and wall-thickness. Fully automatic measurements on zirconium liner thickness and Zircaloy-2 thickness are performed with high accuracy to an order of 2 μm. This newly developed system is very useful in assuring the liner layer and Zircaloy-2 thickness in the production of high-quality cladding tubes

  13. CURRENT BUILDUP IN EMERGING SERPENTINE FLUX TUBES

    International Nuclear Information System (INIS)

    The increase of magnetic flux in the solar atmosphere during active-region formation involves the transport of the magnetic field from the solar convection zone through the lowest layers of the solar atmosphere, through which the plasma β changes from >1 to <1 with altitude. The crossing of this magnetic transition zone requires the magnetic field to adopt a serpentine shape also known as the sea-serpent topology. In the frame of the resistive flux-emergence model, the rising of the magnetic flux is believed to be dynamically driven by a succession of magnetic reconnections which are commonly observed in emerging flux regions as Ellerman bombs. Using a data-driven, three-dimensional (3D) magnetohydrodynamic numerical simulation of flux emergence occurring in active region 10191 on 2002 November 16-17, we study the development of 3D electric current sheets. We show that these currents buildup along the 3D serpentine magnetic-field structure as a result of photospheric diverging horizontal line-tied motions that emulate the observed photospheric evolution. We observe that reconnection can not only develop following a pinching evolution of the serpentine field line, as usually assumed in two-dimensional geometry, but can also result from 3D shearing deformation of the magnetic structure. In addition, we report for the first time on the observation in the UV domain with the Transition Region and Coronal Explorer (TRACE) of extremely transient loop-like features, appearing within the emerging flux domain, which link several Ellermam bombs with one another. We argue that these loop transients can be explained as a consequence of the currents that build up along the serpentine magnetic field.

  14. Clinical evaluation of automatic tube voltage selection in chest CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Tilo; Henry, Simon; Faivre, Jean-Baptiste; Yasunaga, Kanna; Bendaoud, Sofiane; Simeone, Ariana; Remy, Jacques [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain [University Lille Nord de France, Department of Medical Statistics (EA 2694), Lille (France); Flohr, Thomas [Siemens Medical Systems, Department of Research and Development, Forchheim (Germany); Remy-Jardin, Martine [Hospital Calmette, Department of Thoracic Imaging, Lille cedex (France)

    2013-10-15

    To evaluate the clinical impact of automatic tube voltage selection on chest CT angiography (CTA). Ninety-three patients were prospectively evaluated with a CT protocol aimed at comparing two successive CTAs acquired under similar technical conditions except for the kV selection: (1) the initial CTA was systematically obtained at 120 kVp and 90 ref mAs; (2) the follow-up CTA was obtained with an automatic selection of the kilovoltage (Care KV; Siemens Healthcare) for optimised CTA. At follow-up, 90 patients (97 %) underwent CTA with reduced tube voltage, 100 kV (n = 26; 28 %) and 80 kV (n = 64; 69 %), resulting in a significant dose-length-product reduction (follow-up: 87.27; initial: 141.88 mGy.cm; P < 0.0001; mean dose reduction: 38.5 %) and a significant increase in the CNR at follow-up (follow-up: 11.5 {+-} 3.5 HU; initial: 10.9 {+-} 3.7 HU; P = 0.03). The increase in objective image noise at follow-up (follow-up: 23.2 {+-} 6.7 HU vs. 17.8 {+-} 5.1 HU; P < 0.0001) did not alter the diagnostic value of images. Automatic tube voltage selection reduced the radiation dose delivered during chest CT angiograms by 38.5 % while improving the contrast-to-noise ratio of the examinations. (orig.)

  15. Automatic welding of stainless steel instrumentation tubing in a nuclear power station

    International Nuclear Information System (INIS)

    Impulse lines and sample lines associated with instrumentation systems are of pipes and tubes. For this purpose, stainless steel tubes are employed in CANDU type reactors. For joints, wherever necessary, welding is preferred to tube fittings as far as possible. Welding is less costly, requires less space and is less likely to be disturbed by the operator. For welding, an automatic weld machine is used. Essential parts of this machine, namely, power supply, logic circuits, speed control unit, handle, weld head, high frequency unit, pendant box, recorder and gas system are described. Sequence of operation is explained. Procedures of machine testing, quality control and inspection, and maintenance problems are given. Qualifications for operator are enumerated. Problems in maintenance are reported. (M.G.B.)

  16. Development of and experience with automatically operated ultrasonic wall thickness gauging for periodic inspection of heat exchanger tube bundles

    International Nuclear Information System (INIS)

    The demand for an accurate inservice inspection method for ferritic LMFBR steam generator tube bundles resulted in a fast and automatic operating system based upon ultrasonics, which appears suitable for nearly all kinds of heat exchangers. (author)

  17. Application of automatic inspection system to nondestructive test of heat transfer tubes of primary pressurized water cooler in the high temperature engineering test reactor. Joint research

    International Nuclear Information System (INIS)

    Heat transfer tubes of a primary pressurized water cooled (PPWC) in the high temperature engineering test reactor (HTTR) form the reactor pressure boundary of the primary coolant, therefore are important from the viewpoint of safety. To establish inspection techniques for the heat transfer tubes of the PPWC, an automatic inspection system was developed. The system employs a bobbin coil probe, a rotating probe for eddy current testing (ECT) and a rotating probe for ultrasonic testing (UT). Nondestructive test of a half of the heat transfer tubes of the PPWC was carried out by the automatic inspection system during reactor shutdown period of the HTTR (about 55% in the maximum reactor power in this paper). The nondestructive test results showed that the maximum signal-to-noise ratio was 1.8 in ECT. Pattern and phase of Lissajous wave, which were obtained for the heat transfer tube of the PPWC, were different from those obtained for the artificially defected tube. In UT echo amplitude of the PPWC tubes inspected was lower than 20% of distance-amplitude calibration curve. Thus, it was confirmed that there was no defect in depth, which was more than the detecting standard of the probes, on the outer surface of the heat transfer tubes of the PPWC inspected. (author)

  18. Eddy-current inspection of shuttle heat exchanger tube welds

    Science.gov (United States)

    Dodd, Casius V.; Scott, G. W.; Chitwood, L. D.

    1990-01-01

    The goal of this project was to develop the system necessary to demonstrate in the laboratory that an eddy current system can inspect the tubes and welds described, screening for the existence of flaws equal in size to, or larger than, the target flaw. The laboratory system was to include the probe necessary to traverse the tubing, the electronics to drive (i.e., electrically excite) the probe and receive and process signals from it, a data display, data recording, and playback devices, and microprocessor software or firmware necessary to operate the system.

  19. Eddy-current inspection of shuttle heat exchanger tube welds

    International Nuclear Information System (INIS)

    This goal of this project was to develop the system necessary to demonstrate in the laboratory that an eddy-current system can inspect the tubes and welds described above, screening for the existence of flaws equal in size to, or larger than, the target flaw. The laboratory system was to include the probe necessary to traverse the tubing, the electronics to drive (i.e., electrically excite) the probe and receive and process signals from it, a data display, data recording and playback devices, and microprocessor software or firmware necessary to operate the system. 5 refs., 9 figs., 2 tabs

  20. Eddy current test of fin tubes for a heat exchanger

    International Nuclear Information System (INIS)

    Eddy current probes were designed for the test of fin tubes. Fin tubes, often used for heat exchangers, have uneven outer and inner surfaces to enhance the heat emission. The surface roughness make it difficult to detect flaws employing eddy current test(ECT). In order to overcome the difficulties we performed two types of works, one is the delopment of ECT probes, and the other is the signal processing including fast Fourier transform and digital filtering. In the development of ECT probes, we adopted empirical design method. Our ECT probes for fin tubes are inside diameter type. And we are specially concerned about geometric features such as the widths of the coils composing an ECT probe. We fabricated four probes with various coil widths. Eddy current test was performed using those ECT probes on specimens with artificial flaws. After analyzing the output signals, we found that, in order for the effective testing, the width of a coil should be determined considering the pitch of the fins of a tube. And we also learned that the frequency filtering could improve the s/n ratio.

  1. Eddy current inspection of weld defects in tubing

    Science.gov (United States)

    Katragadda, G.; Lord, W.

    1992-01-01

    An approach using differential probes for the inspection of weld defects in tubing is studied. Finite element analysis is used to model the weld regions and defects. Impedance plane signals are predicted for different weld defect types and compared wherever possible with signals from actual welds in tubing. Results show that detection and sizing of defects in tubing is possible using differential eddy current techniques. The phase angle of the impedance plane trajectory gives a good indication of the sizing of the crack. Data on the type of defect can be obtained from the shape of the impedance plane trajectory and the phase. Depending on the skin depth, detection of outer wall, inner wall, and subsurface defects is possible.

  2. Modeling of eddy current probe response for steam generator tubes

    International Nuclear Information System (INIS)

    Sample calculations were performed with a three-dimensional (3-D) finite-element model analysis that describe the response of an eddy current (EC) probe to steam generator (SG) tubing artifacts. Such calculations could be very helpful in understanding and interpreting of EC probe response to complex tube/defect geometries associated with the inservice inspection (ISI) of steam generator (SG) tubing. The governing field equations are in terms of coupled magnetic vector and electric scalar potentials in conducting media and of total or reduced scalar potentials in nonconducting regions. To establish the validity of the model, comparisons of the theoretical and experimental responses of an absolute bobbin probe are given for two types of calibration standard defects. Preliminary results are also presented from a recent theoretical study of the effect of ligament size in axial cracks on EC indications with conventional ISI bobbin probes

  3. Application of AMI 207A automatic welding to the erection engineering of electric instrument tube of nuclear powre plant

    International Nuclear Information System (INIS)

    The industrial application of automatic, intelligent and high-precision parameter-controlled welding equipment has become true long age in the western developed countries. However, this kind of equipment has been seldom used in China, especially on the erection site of nuclear power construction. In the Phase III of Qinshan Nuclear Power Project, we used the American AMI (Arc Machines, Inc.) 208A automatic welding equipment and technology to have all grooves of the electric instrument tubes automatically welded. The practice has proved that the automatic welding is more advanced, highly effective and more economic compared with other welding processes. (authors)

  4. Development of an automatized device for eddy current testing

    International Nuclear Information System (INIS)

    To improve performances in eddy current studies, several tools were developed in the Saclay Laboratory: - ELEFANT is a very flexible software which allows a rapid creation of new NDT applications, preserving anytime a full compatibility between computers, applications, data... used under the same ELEFANT controlkey. - Modulo'STA is a modular hardware designed to be the flexible interface between the probe and the computer, driving the measurement, the probe movement... - rotating EC probes with local rotation facilities allow the control of very long steam generator tubes, even bent

  5. Adjustment of RVA-62 automatic field-current regulator

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, A.A.; Karkazov, E.I.

    1985-08-01

    While the RVA-62 automatic field-current regulator performs adequately with small and medium-size turbogenerators, its stability margin being often sufficiently large to compensate design inaccuracies, a refinement is nevertheless recommended to ensure reliability under no-load as well as during parallel operation of generators into a common busbar group. The procedure is based on necessary adjustments of over 40 units and applies to redesign, measurements, breadboard simulation, settings, reassembly, and testing. First it is necessary to determine the correct number of primary and secondary turns in the universal controlled phase-compounding transformer, taking into account the parameters of associated equipment (autotransformer, filter choke, power rectifier, current transformer) as well as various modes of generator instability and the use of automatic field suppression. Revisions in testing circuitry and procedure are proposed, including more precise and some extra measurements, also replacement of selenium rectifiers with silicon diodes. Adjustments according to this scheme have been made in the RVA-62 regulators for 6-60 kW generators with VT exciters and 3000-12,000 kW generators, including Skoda, Siemens-Schuckert GmbH, Parsons Ltd units.

  6. Evaluation of the applicability of the tube-type automatic fire extinguishing equipment to the cable fire

    International Nuclear Information System (INIS)

    According to the examination standards related to fire protection for commercial nuclear power reactors and the supplementary facilities issued by Nuclear Regulation Authority in June 2013, a tube-type automatic fire extinguishing system for the cable fire, so called Fire-Erase (FE) system, will be implemented as early warning fire detection and extinction system to mitigate the fire damage to the cable trays for the safe shutdown functions. Therefore, it is necessary to acquire the demonstrative data for fire-extinguishing performance of FE system with respect to the cable tray fire. In this report, the cable fire suppression tests under over-current condition (2000A class) in the horizontal and vertical orientation were executed using the non-heat resistant high voltage power cables and the full-scale cable trays equipped with metal lid covered with fire-resistant sheet to prevent the leakage of fire extinguishing agent, and the effectiveness of the FE system was confirmed. (author)

  7. Effect of tube current modulation for dose estimation using a simulation tool on body CT examination

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the effect of tube current modulation for dose estimation of a body computed tomography (CT) examination using a simulation tool. The authors also compared longitudinal variations in tube current values between iterative reconstruction (IR) and filtered back-projection (FBP) reconstruction algorithms. One hundred patients underwent body CT examinations. The tube current values around 10 organ regions were recorded longitudinally from tube current information. The organ and effective doses were simulated by average tube current values and longitudinal modulated tube current values. The organ doses for the bladder and breast estimated by longitudinal modulated tube current values were 20 % higher and 25 % lower than those estimated using the average tube current values, respectively. The differences in effective doses were small (mean, 0.7 mSv). The longitudinal variations in tube current values were almost the same for the IR and FBP algorithms. (authors)

  8. Defect Automatic Identification of Eddy Current Pulsed Thermography

    Directory of Open Access Journals (Sweden)

    Kai Chen

    2014-01-01

    Full Text Available Eddy current pulsed thermography (ECPT is an effective nondestructive testing and evaluation (NDT&E technique, and has been applied for a wide range of conductive materials. Manual selected frames have been used for defects detection and quantification. Defects are indicated by high/low temperature in the frames. However, the variation of surface emissivity sometimes introduces illusory temperature inhomogeneity and results in false alarm. To improve the probability of detection, this paper proposes a two-heat balance states-based method which can restrain the influence of the emissivity. In addition, the independent component analysis (ICA is also applied to automatically identify defect patterns and quantify the defects. An experiment was carried out to validate the proposed methods.

  9. Nondestructive examination of PHWR pressure tube using eddy current technique

    International Nuclear Information System (INIS)

    A pressurized heavy water reactor (PHWR) core has 380 fuel channels contained and supported by a horizontal cylindrical vessel known as the calandria, whereas a pressurized water reactor (PWR) has only a single reactor vessel. The pressure tube, which is a pressure-retaining component, has a 103.4 mm inside diameter x 4.19 mm wall thickness, and is 6.36 m long, made of a zirconium alloy (Zr-2.5 wt% Nb). This provides support for the fuel while transporting the D2O heat-transfer fluid. The simple tubular geometry invites highly automated inspection, and good approach for all inspection. Similar to all nuclear heat-transfer pressure boundaries, the PHWR pressure tube requires a rigorous, periodic inspection to assess the reactor integrity in accordance with the Korea Nuclear Safety Committee law. Volumetric-based nondestructive evaluation (NDE) techniques utilizing ultrasonic and eddy current testing have been adopted for use in the periodic inspection of the fuel channel. The eddy current testing, as a supplemental NDE method to ultrasonic testing, is used to confirm the flaws primarily detected through ultrasonic testing, however, eddy current testing offers a significant advantage in that its ability to detect surface flaws is superior to that of ultrasonic testing. In this paper, effectiveness of flaw detection and the depth sizing capability by eddy current testing for the inside surface of a pressure tube, will be introduced. As a result of this examination, the ET technique is found to be useful only as a detection technique for defects because it can detect fine defects on the surface with high resolution. However, the ET technique is not recommended for use as a depth sizing method because it has a large degree of error for depth sizing.

  10. Alloy 800 SG tubing: current status and future challenges

    International Nuclear Information System (INIS)

    Alloy 800 has been used for steam generator (SG) tubing for more than 30 years, primarily in CANDU reactors and in reactors in Germany. The grade of Alloy 800 tubing used for this service has a controlled Ti/C ratio (≥12 for CANDU SGs), and this specification is sometimes termed Alloy 800 M or Alloy 800 NG . There have been very few corrosion-related flaws detected in this material in SG service, and, until recently, no incidences of cracking. There has been extensive R and D carried out on Alloy 800 tubing, both in Canada and elsewhere, under a variety of operating conditions, including shutdowns, which show that it has excellent resistance to corrosion-related degradation under specified and appropriate operating conditions. These R and D findings are reflected in the in-service experience. It has been shown from the R and D that Alloy 800 is susceptible to corrosion under acidic conditions, in particular those that can arise as a consequence of phosphate water treatment or sulphur-related contamination. In common with all SG tubing materials, Alloy 800 is susceptible to corrosion under layup conditions if the pH is low, as can occur when reduced sulphates may be present (polythionic acids). SG layup, and startup and shutdown transients, are probably the most vulnerable conditions for SG tubing when both oxidizing conditions and acid-forming impurities may be present (chloride and sulphate, for example). Most of this corrosion is expected to occur in crevices (such as the tube-to-tubesheet, TTS, and tube-to-support plate, TSP, crevices) or under deposits (including tubesheet sludge piles and thick freespan deposits). This has been the experience in SGs tubed with Alloy 600. A key input into the life cycle management of SGs is the probability of degradation occurring during the remaining, and any extended, life of the SG. For SGs with Alloy 800 tubing, the lack of corrosion-related degradation to date implies that assumptions need to be made about the

  11. Alloy 800 SG tubing: current status and future challenges

    Energy Technology Data Exchange (ETDEWEB)

    Tapping, R.L.; Lu, Y.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Pandey, M.D. [Univ. of Waterloo, Inst. for Risk Research, Waterloo, Ontario (Canada)

    2007-07-01

    Alloy 800 has been used for steam generator (SG) tubing for more than 30 years, primarily in CANDU reactors and in reactors in Germany. The grade of Alloy 800 tubing used for this service has a controlled Ti/C ratio ({>=}12 for CANDU SGs), and this specification is sometimes termed Alloy 800 M or Alloy 800 NG . There have been very few corrosion-related flaws detected in this material in SG service, and, until recently, no incidences of cracking. There has been extensive R and D carried out on Alloy 800 tubing, both in Canada and elsewhere, under a variety of operating conditions, including shutdowns, which show that it has excellent resistance to corrosion-related degradation under specified and appropriate operating conditions. These R and D findings are reflected in the in-service experience. It has been shown from the R and D that Alloy 800 is susceptible to corrosion under acidic conditions, in particular those that can arise as a consequence of phosphate water treatment or sulphur-related contamination. In common with all SG tubing materials, Alloy 800 is susceptible to corrosion under layup conditions if the pH is low, as can occur when reduced sulphates may be present (polythionic acids). SG layup, and startup and shutdown transients, are probably the most vulnerable conditions for SG tubing when both oxidizing conditions and acid-forming impurities may be present (chloride and sulphate, for example). Most of this corrosion is expected to occur in crevices (such as the tube-to-tubesheet, TTS, and tube-to-support plate, TSP, crevices) or under deposits (including tubesheet sludge piles and thick freespan deposits). This has been the experience in SGs tubed with Alloy 600. A key input into the life cycle management of SGs is the probability of degradation occurring during the remaining, and any extended, life of the SG. For SGs with Alloy 800 tubing, the lack of corrosion-related degradation to date implies that assumptions need to be made about the

  12. Patient specific tube current modulation for CT dose reduction

    Science.gov (United States)

    Jin, Yannan; Yin, Zhye; Yao, Yangyang; Wang, Hui; Wu, Mingye; Kalra, Mannudeep; De Man, Bruno

    2015-03-01

    Radiation exposure during CT imaging has drawn growing concern from academia, industry as well as the general public. Sinusoidal tube current modulation has been available in most commercial products and used routinely in clinical practice. To further exploit the potential of tube current modulation, Sperl et al. proposed a Computer-Assisted Scan Protocol and Reconstruction (CASPAR) scheme [6] that modulates the tube current based on the clinical applications and patient specific information. The purpose of this study is to accelerate the CASPAR scheme to make it more practical for clinical use and investigate its dose benefit for different clinical applications. The Monte Carlo simulation in the original CASPAR scheme was substituted by the dose reconstruction to accelerate the optimization process. To demonstrate the dose benefit, we used the CATSIM package generate the projection data and perform standard FDK reconstruction. The NCAT phantom at thorax position was used in the simulation. We chose three clinical cases (routine chest scan, coronary CT angiography with and without breast avoidance) and compared the dose level with different mA modulation schemes (patient specific, sinusoidal and constant mA) with matched image quality. The simulation study of three clinical cases demonstrated that the patient specific mA modulation could significantly reduce the radiation dose compared to sinusoidal modulation. The dose benefits depend on the clinical application and object shape. With matched image quality, for chest scan the patient specific mA profile reduced the dose by about 15% compared to the sinusoid mA modulation; for the organ avoidance scan the dose reduction to the breast was over 50% compared to the constant mA baseline.

  13. A preliminary study into performing routine tube output and automatic exposure control quality assurance using radiology information system data

    International Nuclear Information System (INIS)

    Data are currently being collected from hospital radiology information systems in the North West of the UK for the purposes of both clinical audit and patient dose audit. Could these data also be used to satisfy quality assurance (QA) requirements according to UK guidance? From 2008 to 2009, 731 653 records were submitted from 8 hospitals from the North West England. For automatic exposure control QA, the protocol from Inst. of Physics and Engineering in Medicine (IPEM) report 91 recommends that milli amperes per second can be monitored for repeatability and reproducibility using a suitable phantom, at 70-81 kV. Abdomen AP and chest PA examinations were analysed to find the most common kilo voltage used with these records then used to plot average monthly milli amperes per second with time. IPEM report 91 also recommends that a range of commonly used clinical settings is used to check output reproducibility and repeatability. For each tube, the dose area product values were plotted over time for two most common exposure factor sets. Results show that it is possible to do performance checks of AEC systems; however more work is required to be able to monitor tube output performance. Procedurally, the management system requires work and the benefits to the workflow would need to be demonstrated. (authors)

  14. Iterative reconstruction for quantitative computed tomography analysis of emphysema: consistent results using different tube currents

    Directory of Open Access Journals (Sweden)

    Yamashiro T

    2015-02-01

    Full Text Available Tsuneo Yamashiro,1 Tetsuhiro Miyara,1 Osamu Honda,2 Noriyuki Tomiyama,2 Yoshiharu Ohno,3 Satoshi Noma,4 Sadayuki Murayama1 On behalf of the ACTIve Study Group 1Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan; 2Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 3Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 4Department of Radiology, Tenri Hospital, Tenri, Nara, Japan Purpose: To assess the advantages of iterative reconstruction for quantitative computed tomography (CT analysis of pulmonary emphysema. Materials and methods: Twenty-two patients with pulmonary emphysema underwent chest CT imaging using identical scanners with three different tube currents: 240, 120, and 60 mA. Scan data were converted to CT images using Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D and a conventional filtered-back projection mode. Thus, six scans with and without AIDR3D were generated per patient. All other scanning and reconstruction settings were fixed. The percent low attenuation area (LAA%; < -950 Hounsfield units and the lung density 15th percentile were automatically measured using a commercial workstation. Comparisons of LAA% and 15th percentile results between scans with and without using AIDR3D were made by Wilcoxon signed-rank tests. Associations between body weight and measurement errors among these scans were evaluated by Spearman rank correlation analysis. Results: Overall, scan series without AIDR3D had higher LAA% and lower 15th percentile values than those with AIDR3D at each tube current (P<0.0001. For scan series without AIDR3D, lower tube currents resulted in higher LAA% values and lower 15th percentiles. The extent of emphysema was significantly different between each pair among scans when not using AIDR3D (LAA%, P<0.0001; 15th percentile, P<0.01, but was not

  15. An automatic monitoring system of leak current for testing TGC detectors based on LabVIEW

    International Nuclear Information System (INIS)

    An automatic monitoring system of leak current for testing TGC detectors with high voltage was set up by using the graphic LabVIEW platform and NI 4351 data acquisition card. The leak current was automatically monitored and recorded with this system, the time and the value of the leak current were showed instantly. Good efficiency and precision of monitoring were obtained. (authors)

  16. Localization of defects in steam generator tubes using a multi-coil eddy current probe dedicated to high speed inspection

    Energy Technology Data Exchange (ETDEWEB)

    Joubert, P.-Y.; Le Bihan, Y.; Placko, D. [Ecole Normale Superieure de Cachan (France). Laboratoire d' Electricite Signaux et Robotique

    2002-07-01

    Steam generator (SG) tubing of pressurized water reactor in nuclear plants must be rapidly and accurately checked in order to detect defects in their early stages. In this paper, the authors present a multi-coil eddy current (EC) probe allowing both high speed inspection and circumferential localization of defects in the tube wall. A method of multi-coil EC signal processing, based on a continuous wavelet transform combined with a maximum likelihood diagnosis, is elaborated in order to enhance the detection performances and to provide automatic localization of defects. The inspection of SG tube samples shows good localization performances for defects as small as 10% deep, 15 mm long and 100 {mu}m wide outer diameter notches, of both circumferential and axial orientations. (author)

  17. Improved eddy-current inspection for steam generator tubing

    International Nuclear Information System (INIS)

    Computer programs have been written to allow the analysis of different types of eddy-current probes and their performance under different steam generators test conditions. The probe types include the differential bobbin probe, the absolute bobbin probe, the pancake probe and the reflection probe. The generator test conditions include tube supports, copper deposits, magnetite deposits, denting, wastage, pitting, cracking, and intergranular attack. These studies are based mostly on computed values, with the limited number of test specimens available used to verify the computed results. The instrument readings were computed for a complete matrix of the different test conditions, and then the test conditions determined as a function of the readings by a least-squares technique. A comparison was made of the errors in fit and instrument drift for the different probe types. The computations of the change in instrument reading due to the defects have led to an inversion technique in which the defect properties can be computed from the instrument readings. This has been done both experimentally and analytically for each of these probe types. Measurements and computations were also made of the effect of sampling rate on the accuracy of the defect depth measurements for the bobbin probe. For simple defect signals, a relative coarse sample rate is sufficient to determine the defect depth. The frequency response of the signal produced as the coil is scanned past the defect determines the desired response of the instrument amplifiers. Neural networks have been applied to the analysis of eddy-current defect scans in the presence of other signals, such as tube supports, magnetite deposits, and copper deposits

  18. Eddy current inspection of steam generator tubing plugs

    International Nuclear Information System (INIS)

    In response to the issues raised regarding the integrity of nuclear steam generator tubing plugs manufactured from certain heats of Inconel 600, Westinghouse engineers have developed, qualified and implemented an eddy current inspection system for the in-place assessment of these plugs. The heart of the system is a robotic and effector which delivers an eddy current sensor through the reduced diameter of the plug expander and actuates the coil to physical contact with the expanded inside bore of the plug. Once deployed, the eddy current sensor is rotated along a helical path to produce a detailed scan of the plug surface above the final position of the expander. This testing produces an isometric display of degradation due to primary water stress corrosion cracking, on the inside surface of the plug. To date, successful inspections have been conducted at two nuclear units with two different robotic delivery systems. While designed specifically for mechanical plugs with a bottle bore cavity, the inspection system can also be used for expanded straight bore plugs. Details of the inspection system along with a discussion of qualification activities and actual field results are presented in this paper

  19. Confining flux tubes in a current algebra approach

    CERN Document Server

    Benson, K M; Benson, K M; Saadi, M

    1995-01-01

    We describe flux tubes and their interactions in a low energy sigma model induced by SU(\\NF) \\goto SO(\\NF) flavor symmetry breaking in SO(N_c) QCD. Unlike standard QCD, this model allows gauge confinement to manifest itself in the low energy theory, which has unscreened spinor color sources and global Z_2 flux tubes. We construct the flux tubes and show how they mediate the confinement of spinor sources. We further examine the flux tubes' quantum stability, spectrum and interactions. We find that flux tubes are Alice strings, despite ambiguities in defining parallel transport. However, loops of flux tube cannot support skyrmion number, unlike gauged Alice strings whose loops support monopole charge. This model, while phenomenologically nonviable, thus affords a perspective on both the dynamics of confinement and on subtleties which arise for global Alice strings.

  20. A method and sensor for the eddy current non destructive testing of thin tubes; Procede de controle non destructif d`un tube mince par courants de Foucault

    Energy Technology Data Exchange (ETDEWEB)

    Sartre, B.; Miller, D.; Placko, D.

    1995-06-02

    In order to control the wear (cracking or thinning) of vapor generator tubes, especially in PWR reactors, due to the friction between the tubes and dampers, an eddy current control system is proposed where the transducer is run through the tubes, and measures the tube wall thickness or tube-block clearance through impedance measurements, taking into account the variation of the sensor-to-tube distance. 8 fig.

  1. Improved eddy-current inspection for steam generator tubing

    International Nuclear Information System (INIS)

    Computer programs have been written to allow the analysis of different types of eddy-current probes and their performance under different steam generator test conditions. The probe types include the differential bobbin probe, the absolute bobbin probe, the pancake probe and the reflection probe. The generator test conditions include tube supports, copper deposits, magnetite deposits, denting, wastage, pitting, cracking and IGA. These studies are based mostly on computed values, with the limited number of test specimens available used to verify the computed results. The instrument readings were computed for a complete matrix of the different test conditions, and then the test conditions determined as a function of the readings by a least-squares technique. A comparison was made of the errors in fit and instrument drift for the different probe types. The computations of the change in instrument reading due to the defects have led to an ''inversion'' technique in which the defect properties can be computed from the instrument readings. This has been done both experimentally and analytically for each of these probe types. 3 refs., 13 figs., 1 tab

  2. On-line current feed and computer aided control tactics for automatic balancing head

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In the designed automatic balancing head,a non-contact induction transformer is used to deliver driving energy to solve the problem of current fed and controlling on-line.Computer controlled automatic balancing experiments with phase-magnitude control tactics were performed on a flexible rotor system.Results of the experiments prove that the energy feeding method and the control tactics are effective in the automatic balancing head for vibration controlling.

  3. Current practices for ultrasonic and radiographic examination of tubes, tube plates and tube-plate welds of tube bundles in heat exchangers. Chapter 3

    International Nuclear Information System (INIS)

    The chapter describes the ultrasonic and radiographic inspection procedures that are applied to heat exchanger tube bundles. The inspection process starts with the ultrasonic examination of the tubes and tube plates during manufacture, followed by radiography of the tube-to-tube-plate welds during fabrication of the tube bundle. Ultrasonic methods are explained for welds which are amenable to this type of inspection. For the in-service inspection of tube bundles the chapter relates the authors' experiences on the ultrasonic inspection of tubes and tube plates in the Prototype Fast Breeder Reactor at Dounreay. At the end of the chapter some comments are made about future ultrasonic and radiographic developments for tube bundles. (author)

  4. TU-EF-204-01: Accurate Prediction of CT Tube Current Modulation: Estimating Tube Current Modulation Schemes for Voxelized Patient Models Used in Monte Carlo Simulations.

    OpenAIRE

    McMillan, K; Bostani, M; McCollough, C; McNitt-Gray, M

    2015-01-01

    PURPOSE: Most patient models used in Monte Carlo-based estimates of CT dose, including computational phantoms, do not have tube current modulation (TCM) data associated with them. While not a problem for fixed tube current simulations, this is a limitation when modeling the effects of TCM. Therefore, the purpose of this work was to develop and validate methods to estimate TCM schemes for any voxelized patient model. METHODS: For 10 patients who received clinically-indicated chest (n=5) and ab...

  5. Application of automatic tube current modulation on image quality and radiation dose at abdominal CT%自动管电流调制技术对腹部CT图像质量及辐射剂量影响的体模研究

    Institute of Scientific and Technical Information of China (English)

    王倩; 赵心明; 宋俊峰; 郭宁; 朱颖; 刘建新; 綦维维; 武靖; 梁媛

    2013-01-01

    .20 mSv.NI值与图像质量主、客观评价指标及辐射剂量指标间呈高度线性相关(r=0.871~0.982,P值均<0.05).实验组NI =4 ~7组与对照组间SD、CNR差异均无统计学意义(t值分别为-1.63 ~-0.17,0.03 ~1.12,P值均>0.05).实验组NI=4~ 10组与对照组间LCD评分差异均无统计学意义(Z值为-1.637 ~0.000,P值均>0.05).实验组NI =4 ~ 13组与对照组间HCD得分差异均无统计学意义(Z值为-1.423 ~0.000,P值均>0.05).3名医师对LCD、HCD评分的Kappa一致性检验结果分别为0.743、0.795.结论 在腹部CT扫描中应用自动管电流调制技术可确保图像质量,同时降低辐射剂量.%Objective To investigate the effect of automatic tube current modulation (ATCM) on image quality and radiation dose for abdominal CT.Methods An abdomen-equivalent tissue model in the present study was developed,by referring to the CTP515 auxiliary performance testing model made by the internationally recognized Phantom Laboratory,in conjunction with the real data from 68 Chinese male subjects with BMI between 18 to 24 kg/cm2 (subjects with fatty liver,cirrhosis,intraperitoneal huge tumor,ascites or pleural effusion or who were under 18 years old were excluded).Catphan600 performance served as observation object,and simulating adult abdominal CT low and high contrast characteristics to research.Control groups were scanned with CT protocol at fixed 120 kV,450 mA and experimental group were scanned with the same tube voltage and variable current range from 10 to 450 mA (NI value:4 to 20),respectively.CT value was measured by homogeneous area in the center of Catphan600 to verify the phantom for X-ray attenuation of equivalence.CT dose index (CTDIvol),size-specific dose estimates (SSDE),dose length product (DLP),image noise (SD) and contrast to noise ratio (CNR) were recorded and measured.Fifteen mm diameter low-contrast detectability in CTP515 and high-contrast detectability in CTP528 at Catphan600 were

  6. Radially Focused Eddy Current Sensor for Detection of Longitudinal Flaws in Metallic Tubes

    Science.gov (United States)

    Wincheski, Russell A. (Inventor); Simpson, John W. (Inventor); Fulton, James P. (Inventor); Nath, Shridhar C. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor)

    1999-01-01

    A radially focused eddy current sensor detects longitudinal flaws in a metal tube. A drive coil induces eddy currents within the wall of the metal tube. A pick-up cod is spaced apart from the drive coil along the length of the metal tube. The pick@up coil is positioned with one end thereof lying adjacent the wall of the metal tube such that the pick-up coil's longitudinal axis is perpendicular to the wall of the metal tube. To isolate the pick-up coil from the magnetic flux of the drive coil and the flux from the induced eddy currents. except the eddy currents diverted by a longitudinal flaw. an electrically conducting material high in magnetic permeability surrounds all of the pick-up coil except its one end that is adjacent the walls of the metal tube. The electrically conducting material can extend into and through the drive coil in a coaxial relationship therewith.

  7. Expert system for the automatic analysis of the Eddy current signals from the monitoring of vapor generators of a PWR, type reactor

    International Nuclear Information System (INIS)

    The automatization of the monitoring of the steam generator tubes required some developments in the field of data processing. The monitoring is performed by means of Eddy current tests. Improvements in signal processing and in pattern recognition associated to the artificial intelligence techniques induced EDF (French Electricity Company) to develop an automatic signal processing system. The system, named EXTRACSION (French acronym for Expert System for the Processing and classification of Signals of Nuclear Nature), insures the coherence between the different fields of knowledge (metallurgy, measurement, signals) during data processing by applying an object oriented representation

  8. Multifrequency Eddy current testing of heat exchange tubes with a rotating probe

    International Nuclear Information System (INIS)

    Multi-frequency eddy current analyses have been used in France industrially since 1975. In light of the experienced gained during many steam generator inspections, this technique was applied to the examination of sheet and tube heat exchangers featuring tubes in very different materials such as copper, stainless steel and titanium. The principle of multi-frequency Eddy current inspection is first reviewed, using the example of a condenser with nickel alloy tubes (Inconel, Incoloy). This is followed by the description of a specific application of this technique to a condenser with titanium tubes, analyzed with a rotating local probe

  9. Automatic thickness measuring system of zirconium and zircaloy-2 layers of zirconium liner cladding tubes for boiling water reactor

    International Nuclear Information System (INIS)

    An automatic measuring system using ultrasonic method and electromagnetic method has been developed to measure the thickness of zirconium and zircaloy-2 layers. The sophisticated mechanism and the unique signal processing for suppression of several types of error enable high accurate measurement. The standard deviation of the liner thickness measurement is 2.2 μm and that of mother layer measurement is 3.0 μm. This system is very useful to assure the thickness of each layer and to produce high quality zirconium liner cladding tubes. (author)

  10. Automatic method of measuring silicon-controlled-rectifier holding current

    Science.gov (United States)

    Maslowski, E. A.

    1972-01-01

    Development of automated silicon controlled rectifier circuit for measuring minimum anode current required to maintain rectifiers in conducting state is discussed. Components of circuit are described and principles of operation are explained. Illustration of circuit is provided.

  11. Expert system for eddy current signal analysis: non destructive testing of steam generator tubings

    International Nuclear Information System (INIS)

    Automatic analysis, by computer, of defect signals in steam generator tubes, based on Eddy current multifrequency technique, is must often inefficient due to pilgrim noise. The first step is to use a method that allows us to eleminate the noise: the adaptative interpolation. Thanks to this method, which ensures reliable data on each channel, the analysis can be realised by taking into account the data corresponding to each basic or mixed channel. By correlating these diverse data, we can class the signals according to two types of defects: single defects (symmetrical), multiple defects (several in the same place). The second step is to use an expert system which allows a reliable diagnosis for whatever family the defect belongs to. According to this classification, analysis is continued and results in the characterization of the defect. The expert system has already been developed with the general purpose application expert system shell SUPER, which is briefly described. The knowledge base (SOCRATE) and the specific tools developed for this application are thoroughly described. The first results obtained with signals corresponding to real defects, that have been recorded in different places, are presented and discussed. The expert system is revealed efficient in all the studied cases, even with signals obtained in very noisy environments

  12. Evaluation of the use of automatic exposure control and automatic tube potential selection in low-dose cerebrospinal fluid shunt head CT

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Adam N.; Bagade, Swapnil; Chatterjee, Arindam; Hicks, Brandon; McKinstry, Robert C. [Barnes Jewish Hospital, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Washington University School of Medicine, St. Louis, MO (United States); Vyhmeister, Ross [Washington University School of Medicine, St. Louis, MO (United States); Ramirez-Giraldo, Juan Carlos [Siemens Healthcare, Malvern, PA (United States)

    2015-03-17

    Cerebrospinal fluid shunts are primarily used for the treatment of hydrocephalus. Shunt complications may necessitate multiple non-contrast head CT scans resulting in potentially high levels of radiation dose starting at an early age. A new head CT protocol using automatic exposure control and automated tube potential selection has been implemented at our institution to reduce radiation exposure. The purpose of this study was to evaluate the reduction in radiation dose achieved by this protocol compared with a protocol with fixed parameters. A retrospective sample of 60 non-contrast head CT scans assessing for cerebrospinal fluid shunt malfunction was identified, 30 of which were performed with each protocol. The radiation doses of the two protocols were compared using the volume CT dose index and dose length product. The diagnostic acceptability and quality of each scan were evaluated by three independent readers. The new protocol lowered the average volume CT dose index from 15.2 to 9.2 mGy representing a 39 % reduction (P < 0.01; 95 % CI 35-44 %) and lowered the dose length product from 259.5 to 151.2 mGy/cm representing a 42 % reduction (P < 0.01; 95 % CI 34-50 %). The new protocol produced diagnostically acceptable scans with comparable image quality to the fixed parameter protocol. A pediatric shunt non-contrast head CT protocol using automatic exposure control and automated tube potential selection reduced patient radiation dose compared with a fixed parameter protocol while producing diagnostic images of comparable quality. (orig.)

  13. Task-driven tube current modulation and regularization design in computed tomography with penalized-likelihood reconstruction

    Science.gov (United States)

    Gang, G. J.; Siewerdsen, J. H.; Stayman, J. W.

    2016-03-01

    Purpose: This work applies task-driven optimization to design CT tube current modulation and directional regularization in penalized-likelihood (PL) reconstruction. The relative performance of modulation schemes commonly adopted for filtered-backprojection (FBP) reconstruction were also evaluated for PL in comparison. Methods: We adopt a task-driven imaging framework that utilizes a patient-specific anatomical model and information of the imaging task to optimize imaging performance in terms of detectability index (d'). This framework leverages a theoretical model based on implicit function theorem and Fourier approximations to predict local spatial resolution and noise characteristics of PL reconstruction as a function of the imaging parameters to be optimized. Tube current modulation was parameterized as a linear combination of Gaussian basis functions, and regularization was based on the design of (directional) pairwise penalty weights for the 8 in-plane neighboring voxels. Detectability was optimized using a covariance matrix adaptation evolutionary strategy algorithm. Task-driven designs were compared to conventional tube current modulation strategies for a Gaussian detection task in an abdomen phantom. Results: The task-driven design yielded the best performance, improving d' by ~20% over an unmodulated acquisition. Contrary to FBP, PL reconstruction using automatic exposure control and modulation based on minimum variance (in FBP) performed worse than the unmodulated case, decreasing d' by 16% and 9%, respectively. Conclusions: This work shows that conventional tube current modulation schemes suitable for FBP can be suboptimal for PL reconstruction. Thus, the proposed task-driven optimization provides additional opportunities for improved imaging performance and dose reduction beyond that achievable with conventional acquisition and reconstruction.

  14. Automatic control system for measuring currents produced by ionization chambers

    International Nuclear Information System (INIS)

    Ionization Chambers in current mode operation are usually used in Nuclear Metrology. Activity measurements are quickly performed by Ionization Chambers, with very good precision. For this purpose measurements of very low ionization currents, carried out by high quality instrumentation, are required. Usually, electrometers perform the current integration method under command of signals from an automation system, in order to reduce the measurement uncertainties. Among the measurement systems at the Laboratorio de Metrologia Nuclear (LMN) of IPEN, there are two ionization chamber systems. In the present work, an automation system developed for current integration measurements is described. This automation system is composed by software (graphic interface and control) and an electronic module connected to a microcomputer, by means of a commercial data acquisition card. Several test measurements were performed in order to determine the intrinsic uncertainty, linearity and stability of the system. Using calibrated radioactive solutions, the IG12/A20 chamber calibration factors for 18F and 153Sm were obtained, making possible to determine activities of these radionuclides. (author)

  15. Sausage Instabilities on top of Kinking Lengthening Current-Carrying Magnetic Flux Tubes

    Science.gov (United States)

    von der Linden, Jens; You, Setthivoine

    2015-11-01

    Observations indicate that the dynamics of magnetic flux tubes in our cosmos and terrestrial experiments involve fast topological change beyond MHD reconnection. Recent experiments suggest that hierarchies of instabilities coupling disparate plasma scales could be responsible for this fast topological change by accessing two-fluid and kinetic scales. This study will explore the possibility of sausage instabilities developing on top of a kink instability in lengthening current-carrying magnetic flux tubes. Current driven flux tubes evolve over a wide range of aspect ratios k and current to magnetic flux ratios λ . An analytical stability criterion and numerical investigations, based on applying Newcomb's variational approach to idealized magnetic flux tubes with core and skin currents, indicate a dependence of the stability boundaries on current profiles and overlapping kink and sausage unstable regions in the k - λ trajectory of the flux tubes. A triple electrode planar plasma gun (Mochi.LabJet) is designed to generate flux tubes with discrete core and skin currents. Measurements from a fast-framing camera and a high resolution magnetic probe are being assembled into stability maps of the k - λ space of flux tubes. This work was sponsored in part by the US DOE Grant DE-SC0010340.

  16. Application of Pulsed Eddy Current for Depth Measurement of Steam Generator's Wear scar tube standard

    International Nuclear Information System (INIS)

    The integrity of stem generator tube in nuclear power plant is the critical problem but the particular area on the stem generator tube could be worn away by inside impurities, fluid flow and vibration from the outside environment. At the present, the inspection of stem generator tube has been performed by using a conventional eddy current testing. Although the conventional eddy current testing is a powerful method to detect flaws of tube in online processing, it is difficult to measure the deep depth differences of the tube. Because eddy current density has changed its magnitude with distance from the surface. Whereas, the pulsed eddy current technique has been widely employed for deep depth inspection of structures such as plate, tubes. For more effective inspection, the pulsed eddy current system is enveloped to control a depth difference and submitted the multi-pointing method to select a criteria which could be obtained depth differences by the period of resistivity on the pulsed eddy current transient signals. In this paper, we used the pulsed eddy current technique to improve the capability of depth difference measurement and studied multi-pointing method to evaluate the thickness with variation of resistivity.

  17. Improved eddy-current inspection for steam generator tubing

    International Nuclear Information System (INIS)

    A comparison was made of different types of probes and their performance under different steam generator test conditions. The probe types include the differential bobbin probe, the absolute bobbin probe, the pancake probe and the reflection probe. The generator test conditions include tube supports, copper deposits, magnetite deposits, denting, wastage, pitting, cracking and IGA. The study was based mostly on computed values, with the limited number of test specimens available used to verify the computed results. The instrument readings were computed for a complete matrix of the different test conditions, and then the test conditions determined as a function of the readings in a least-squares technique. A comparison was made in the errors in fit and instrument drift for the different probe types. Measurements and computations were also made of the effect of sampling rate on the accuracy of the defect depth measurement for the bobbin probe. For simple defect signals, a relatively coarse sample rate is sufficient to determine the defect depth. The frequency response of the signal produced as the coil is scanned past the defect determines the desired response of the instrument amplifiers. The computations of the change in instrument reading due to the defects have led to an inversion technique in which the defect properties can be computed from the instrument readings. This has been done both experimentally and analytically for each of these probe types. Experimental measurements have been made for the different probes, including the application of the reflection probe to IGA standards. These reflection probe measurements were made on the tube outer surface with a very sharply focused probe to determine material properties, and from the bore with their standard inspection probe to determine how well this condition can be measured in the field

  18. Study on focusing characteristic of acceleration tube in high current implanter

    International Nuclear Information System (INIS)

    The accelerating tube is one of the most important parts in high current implanter which provides the desired energy and focusing for ion beam. The factors affecting focus characteristic in high current implanter with three gap acceleration tube are discussed. Focusing degrees of different energy ion beam are computed, and the electric field required to prevent beam expansion due to space charge effect are analyzed. The beam envelope inside the three acceleration gap shows a decrease of the beam radius with the increase of the accelerating voltage ratio up to the optimal value. Beyond this optimal value the beam lines make a crossover with the axis of the accelerating tube

  19. Data analysis algorithms for flaw sizing based on eddy current rotating probe examination of steam generator tubes

    International Nuclear Information System (INIS)

    Computer-aided data analysis tools can help improve the efficiency and reliability of flaw sizing based on nondestructive examination data. They can further help produce more consistent results, which is important for both in-service inspection applications and for engineering assessments associated with steam generator tube integrity. Results of recent investigations at Argonne on the development of various algorithms for sizing of flaws in steam generator tubes based on eddy current rotating probe data are presented. The research was carried out as part of the activities under the International Steam Generator Tube Integrity Program (ISG-TIP) sponsored by the U.S. Nuclear Regulatory Commission. A computer-aided data analysis tool has been developed for off-line processing of eddy current inspection data. The main objectives of the work have been to a) allow all data processing stages to be performed under the same user interface, b) simplify modification and testing of signal processing and data analysis scripts, and c) allow independent evaluation of viable flaw sizing algorithms. The focus of most recent studies at Argonne has been on the processing of data acquired with the +Point probe, which is one of the more widely used eddy current rotating probes for steam generator tube examinations in the U.S. The probe employs a directional surface riding differential coil, which helps reduce the influence of tubing artifacts and in turn helps improve the signal-to-noise ratio. Various algorithms developed under the MATLAB environment for the conversion, segmentation, calibration, and analysis of data have been consolidated within a single user interface. Data acquired with a number of standard eddy current test equipment are automatically recognized and converted to a standard format for further processing. Because of its modular structure, the graphical user interface allows user-developed routines to be easily incorporated, modified, and tested independent of the

  20. Data analysis algorithms for flaw sizing based on eddy current rotating probe examination of steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Bakhtiari, S.; Elmer, T.W. [Argonne National Laboratory, Nuclear Energy Division, Lemont, Illinois (United States)

    2009-07-01

    Computer-aided data analysis tools can help improve the efficiency and reliability of flaw sizing based on nondestructive examination data. They can further help produce more consistent results, which is important for both in-service inspection applications and for engineering assessments associated with steam generator tube integrity. Results of recent investigations at Argonne on the development of various algorithms for sizing of flaws in steam generator tubes based on eddy current rotating probe data are presented. The research was carried out as part of the activities under the International Steam Generator Tube Integrity Program (ISG-TIP) sponsored by the U.S. Nuclear Regulatory Commission. A computer-aided data analysis tool has been developed for off-line processing of eddy current inspection data. The main objectives of the work have been to a) allow all data processing stages to be performed under the same user interface, b) simplify modification and testing of signal processing and data analysis scripts, and c) allow independent evaluation of viable flaw sizing algorithms. The focus of most recent studies at Argonne has been on the processing of data acquired with the +Point probe, which is one of the more widely used eddy current rotating probes for steam generator tube examinations in the U.S. The probe employs a directional surface riding differential coil, which helps reduce the influence of tubing artifacts and in turn helps improve the signal-to-noise ratio. Various algorithms developed under the MATLAB environment for the conversion, segmentation, calibration, and analysis of data have been consolidated within a single user interface. Data acquired with a number of standard eddy current test equipment are automatically recognized and converted to a standard format for further processing. Because of its modular structure, the graphical user interface allows user-developed routines to be easily incorporated, modified, and tested independent of the

  1. Dose reduction in subsecond multislice spiral CT examination of children by online tube current modulation

    International Nuclear Information System (INIS)

    The potential of online tube current modulation in subsecond multislice spiral CT (MSCT) examinations of children to reduce the dose without a loss in image quality is investigated in a controlled patient study. The dose can be reduced for oval patient sectional view without an increase in noise if the tube current is reduced where the patient diameter and, consequently, attenuation are small. We investigated a product version of an online control for tube current in a SOMATOM Sensation 4 (Siemens, Forchheim). We evaluated image quality, noise and dose reduction for examinations with online tube current modulation in 30 MSCT of thorax/abdomen and abdomen and compared mA s for tube current modulation to the mA s in standard weight-adapted children protocols. Image quality was rated as ''very good,'' ''good,'' ''diagnostic'' and ''poor'' in a consensus by three radiologists. Noise was assessed in comparison to 24 MSCT examinations without tube current modulation measured as SD in ROIs. The dose was reduced from 26 to 43% (mean 36%), depending on the patient's geometry and weight. (orig.)

  2. Evaluation and field validation of Eddy-Current array probes for steam generator tube inspection

    International Nuclear Information System (INIS)

    The objective of the Improved Eddy-Current ISI for Steam Generator Tubing program is to upgrade and validate eddy-current inspections, including probes, instrumentation, and data processing techniques for inservice inspection of new, used, and repaired steam generator tubes; to improve defect detection, classification, and characterization as affected by diameter and thickness variations, denting, probe wobble, tube sheet, tube supports, copper and sludge deposits, even when defect types and other variables occur in combination; to transfer this advanced technology to NRC's mobile NDE laboratory and staff. This report describes the design of specialized high-speed 16-coil eddy-current array probes. Both pancake and reflection coils are considered. Test results from inspections using the probes in working steam generators are given. Computer programs developed for probe calculations are also supplied

  3. Research on automatic non-destructive testing system of oil coiled tubing

    Science.gov (United States)

    Guo, Rong; Qiu, Wenbin; Wang, Yuhui; Ren, Jianguang

    2010-10-01

    A method using ultrasonic devices for on-line measurement of oil coiled tubing was proposed. The principle of ultrasonic testing was analyzed. Then, the structure of the system consisting of mechanical system, coupling system, measuring system, control system and system software was determinated. Based on the analysis of technology requirement, measuring technique in which the coiled tubing did not rotate and the probe was static was chosen. The ultrasonic testing probes were triggered in turn. After signal sampling, digital filtering and A / D conversion signal processing, the received echo signals were sent to computer. Through analyzing and accounting, the test results were obtained. Based on VC++.net, A-type ultrasonic and C-type ultrasonic display software and the inspection data processing software were developed. Using Windows programming technology, the software structure and function library were totally open. Therefore, secondary development can be carried out conveniently. Based on the experimental studies, coiled tubing's ultrasonic testing system is developed. The testing results show that the system has specific advantages such as high-adaptation, highefficiency, high- stability, high reliability and can meet the need of the users. The ultrasonic testing technologies proposed in this paper can be applied extensively to other tubes.

  4. Zirconium oxide layer thickness measurement on irradiated PHWR pressure tube by eddy current technique

    International Nuclear Information System (INIS)

    Hydriding is one of the life limiting factors in zircaloy pressure tubes in PHWRs. Hydrogen pick-up in the pressure tube is a direct consequence of the corrosion and oxidation of the internal surface of the pressure tube. Accelerated hydrogen pick-up starts after the oxide layer reaches a critical thickness. Hence development of a non-destructive method for measurement of oxide layer thickness in the pressure tube is very essential in monitoring the condition of the pressure tube in the reactor. Oxide layer thickness can be measured non-destructively using an eddy current technique. The probe contains an eddy current coil driven by a high frequency current which produces a varying magnetic field around the coil. The high frequency electromagnetic field produced by the coil penetrates the non conductive oxide layer and induces eddy currents in the conductive substrate. The eddy currents produce an opposing magnetic field that affects the impedance of the coil. Since the impedance variations are strongly dependent on the distance from the coil to the conducting base metal, the probe produces a voltage signal proportional to the thickness of the non-conductive oxide layer. The results from the development and use of this technique for oxide layer measurement in irradiated pressure tube is presented in this paper. (author)

  5. Development of on-site automatic pipe coating system using heating-shrinkable tube under vacuum condition; Developpement d'un systeme automatise de revetement sur site des canalisations (tubes thermo-retractables sous vide)

    Energy Technology Data Exchange (ETDEWEB)

    Teruyuki, Ikeda [Osaka Gas Co., Ltd. (Japan)

    2000-07-01

    This paper describes the development of a high-quality automatic coating system for the on-site coating on the welded joint of polyethylene-coated steel pipe. The system is able to completely eliminate the harmful air voids which can be left between a steel pipe and a coating tube. The coating tube is shrunken and tightly adheres to the pipe through the heating process under quasi-vacuum pressure. The automatic on-site-coating system improved the reliability of on-site coating for the higher integrity of coating adhesion as compared with the conventional manual coating system. (author)

  6. Analysis method of deposit on steam generator tubes using eddy current

    International Nuclear Information System (INIS)

    The steam generator tubes in operating nuclear power plants have an important problem during their operation time, an accumulation of corrosion products. Such corrosion products form from the secondary side of the plant system, such as carbon steel pipelines, heat exchange shell, and turbine. The accumulation position of corrosion product is mainly on the top of the tubesheet, the tube support structures of the steam generator. It is extinguished as sludge, and as a deposit of the corrosion product. The volume increase and hardening of the sludge eventually cause the tube deformation, and a blockage of the coolant flow of the tube supports. A deposit outside the tube results in reducing the heat transfer through the tube wall, and distorts the eddy current signals during an in service inspection. For the management of steam generator tubes from the problems mentioned previously, several methods were performed. The corrosion products could be reduced by chemical cleaning and sludge lancing. The monitoring of the quantity of sludge and deposit is very important data in the management of steam generator tubes. An eddy current testing (ECT) method is very useful to detect flaws and defects in the steam generator (SG) tubes of nuclear power plants (NPPs) during an in service inspection. Recently, it was reported that deposit loading can be measured using eddy current test data, especially of a bobbin probe. For a precision measurement using a non destructive method, a calibration technique is required using the simulated deposit and signal characteristics from the deposit standard. In this study, a personal computer based device was developed for an analysis of ECT signals. The soft wave program can convert the commercial eddy current data and measure the deposit amount from the calibration data

  7. Current Status on the Development of a Double Wall Tube Steam Generator

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ho Yun; Choi, Byoung Hae; Kim, Jong Man; Kim, Byung Ho

    2007-12-15

    A fast reactor, which uses sodium as a coolant, has a lot of merits as a next generation nuclear reactor. However, the possibility of a sodium-water reaction occurrence hinders the commercialization of this reactor. As one way to improve the reliability of a steam generator, a double-wall tube steam generator is being developed in GEN-4 program. In this report, the current state of the technical developments for a double-wall tube steam generator are reviewed and a future plan for the development of a double-wall tube steam generator is established. The current focuses of this research are an improvement of the heat transfer capability for a double-wall tube and the development of a proper leak detection method for the failure of a double-wall tube during a reactor operation. The ideal goal is an on-line leak detection of a double wall tube to prevent the sodium-water reaction. However, such a method is not developed as yet. An alternative method is being used to improve the reliability of a steam generator by performing a non-destructive test of a double wall tube during the refueling period of a reactor. In this method a straight double wall tube is employed to perform this test easily, but has a difficulty regarding an absorption of a thermal expansion of the used materials. If an on-line leak detection method is developed, the demerits of a straight double-wall tube are avoided by using a helical type double-wall tube, and the probability of a sodium-water reaction can be reduced to a level less than the design-based accident.

  8. Automatic ultrasonic inspection system for wear determination in calandria tubes of Embalse Nuclear Power Plant

    Science.gov (United States)

    Katchadjian, Pablo; Desimone, Carlos; Garcia, Alejandro; Antonaccio, Carlos; Schroeter, Fernando; Molina, Héctor

    2015-03-01

    Embalse Nuclear Power Plant (CNE) (CANDU design) is reaching its end of life and due to elapsed operating time the problem of deformation by accelerated creep occurs in the pressure tubes (PT), leading to a possible contact between calandria tubes (CT), concentric to the PT, and some Liquid Injection Shutdown System (LISS) nozzles that pass underneath them. With determination of CT wear, after the predicted contact occurs, the wear rate of the TC could be determined and thus take less conservative measures over the remaining life of the component. This paper presents the development of an ultrasonic technique for measuring wear in CT, with nominal thickness of 1.34 mm. Because the only access is through the interior of PT, to perform this measurement it is necessary to pass through three different interfaces.

  9. Automatic ultrasonic inspection system for wear determination in calandria tubes of Embalse Nuclear Power Plant

    International Nuclear Information System (INIS)

    Embalse Nuclear Power Plant (CNE) (CANDU design) is reaching its end of life and due to elapsed operating time the problem of deformation by accelerated creep occurs in the pressure tubes (PT), leading to a possible contact between calandria tubes (CT), concentric to the PT, and some Liquid Injection Shutdown System (LISS) nozzles that pass underneath them. With determination of CT wear, after the predicted contact occurs, the wear rate of the TC could be determined and thus take less conservative measures over the remaining life of the component. This paper presents the development of an ultrasonic technique for measuring wear in CT, with nominal thickness of 1.34 mm. Because the only access is through the interior of PT, to perform this measurement it is necessary to pass through three different interfaces

  10. Automatic ultrasonic inspection system for wear determination in calandria tubes of Embalse Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Katchadjian, Pablo, E-mail: katcha@cnea.gov.ar; Desimone, Carlos, E-mail: katcha@cnea.gov.ar; Garcia, Alejandro, E-mail: katcha@cnea.gov.ar [Comisión Nacional de Energía Atómica, Depto. ENDE - INEND, Av. Gral. Paz 1499, Buenos Aires (Argentina); Antonaccio, Carlos; Schroeter, Fernando; Molina, Héctor [Nucleoeléctrica Argentina-SA, Arribeños 3619, Buenos Aires (Argentina)

    2015-03-31

    Embalse Nuclear Power Plant (CNE) (CANDU design) is reaching its end of life and due to elapsed operating time the problem of deformation by accelerated creep occurs in the pressure tubes (PT), leading to a possible contact between calandria tubes (CT), concentric to the PT, and some Liquid Injection Shutdown System (LISS) nozzles that pass underneath them. With determination of CT wear, after the predicted contact occurs, the wear rate of the TC could be determined and thus take less conservative measures over the remaining life of the component. This paper presents the development of an ultrasonic technique for measuring wear in CT, with nominal thickness of 1.34 mm. Because the only access is through the interior of PT, to perform this measurement it is necessary to pass through three different interfaces.

  11. Radiation dose calculations for CT scans with tube current modulation using the approach to equilibrium function

    International Nuclear Information System (INIS)

    Purpose: The approach to equilibrium function has been used previously to calculate the radiation dose to a shift-invariant medium undergoing CT scans with constant tube current [Li, Zhang, and Liu, Med. Phys. 39, 5347–5352 (2012)]. The authors have adapted this method to CT scans with tube current modulation (TCM). Methods: For a scan with variable tube current, the scan range was divided into multiple subscan ranges, each with a nearly constant tube current. Then the dose calculation algorithm presented previously was applied. For a clinical CT scan series that presented tube current per slice, the authors adopted an efficient approach that computed the longitudinal dose distribution for one scan length equal to the slice thickness, which center was at z = 0. The cumulative dose at a specific point was a summation of the contributions from all slices and the overscan. Results: The dose calculations performed for a total of four constant and variable tube current distributions agreed with the published results of Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)]. For an abdomen/pelvis scan of an anthropomorphic phantom (model ATOM 701-B, CIRS, Inc., VA) on a GE Lightspeed Pro 16 scanner with 120 kV, N × T = 20 mm, pitch = 1.375, z axis current modulation (auto mA), and angular current modulation (smart mA), dose measurements were performed using two lines of optically stimulated luminescence dosimeters, one of which was placed near the phantom center and the other on the surface. Dose calculations were performed on the central and peripheral axes of a cylinder containing water, whose cross-sectional mass was about equal to that of the ATOM phantom in its abdominal region, and the results agreed with the measurements within 28.4%. Conclusions: The described method provides an effective approach that takes into account subject size, scan length, and constant or variable tube current to evaluate CT dose to a shift-invariant medium. For a clinical CT scan

  12. Vacuum current and magnetic field induced by an impenetrable flux tube. Dirichlet problem

    CERN Document Server

    Gorkavenko, Volodymyr M

    2015-01-01

    We consider the vacuum polarization effects created by a finite radius magnetic-flux-carrying tube that is impenetrable for quantum matter. The vacuum polarization depends on the choice of a boundary condition at the edge of the tube. We impose a perfectly reflecting (Dirichlet) boundary condition at the edge of the tube on the charged massive scalar matter field which is quantized outside the tube. We find that a current is induced in the vacuum of the quantized scalar field and it circulates around the tube. As a consequence of the Maxwell equation, a magnetic field strength is also induced in the vacuum and is directed along the tube. We restrict our consideration to a plane case. The behavior of the current and the field strength is comprehensively analyzed. In contrast to the model of singular magnetic filament, magnetic field strength is finite at the edge of the string. Induced vacuum effects strongly depend on the tube radius $r_0$. They are quite negligible at $mr_0 > 1$, whereas it becomes noticeabl...

  13. Multi-element eddy current probe. For inspecting steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Savin, E.; Sartre, B. [FRAMATOME, 92 - Paris-La-Defense (France); Placko, D.; Premel, D. [Ecole Nationale Superieure de Cachan, 94 (France)

    2000-10-01

    Framatome and the Ecole Normale Superieure de Cachan are developing a multi-element eddy current probe for inspecting steam generator tubes of 900 MWe PWR reactors. The device is intended to replace much slower rotating probes. Using its measurements, the conductivity image of any point in the tube can be reconstructed, thanks to a numerical, thanks to a numerical model, thus allowing diagnosis. The first trial results on mockups seem already competitive with those obtained using a rotary probe. (authors)

  14. Automatic appraisal of defects in irradiated pins by eddy current testing

    International Nuclear Information System (INIS)

    Eddy current testing is very efficient to inspect the sheaths of spent fuel elements. Automation of the process is developed to replace visual examination of recorded eddy current signals. The method is applied to austenitic steel fuel cans for fast neutron reactors to detect cracks, voids, inclusions... The different types of defects and experimental processes are recalled then automatic detection and the method for defect qualification are presented

  15. Correlation between General Corrosion Behavior and Eddy Current Noise of Alloy 690 Steam Generator Tube

    International Nuclear Information System (INIS)

    Nickel and its oxides are released from the surface of steam generator tubes into the primary water. Released nickel and cobalt is activated to Co-58 and Co-60 in the reactor core by a neutron flux, respectively. These activated corrosion products are the main source of high radiation fields and occupational radiation exposure. In addition, some of the corrosion products redeposit on the fuel cladding, hinder the heat transfer, increase the corrosion rate of the fuel cladding, and finally induce an axial offset anomaly. This phenomenon can decrease core shutdown margin, and thus lead to a down-rating of a plant. Recently, many researchers have reported that the surface states of Alloy 690 tubes affect the corrosion product formation and its release in simulated primary water environments. Meanwhile, the surface states of steam generator tubes affect the noise level of eddy current testing. Noise signals arising from the tubes degrade the probability of detection and sizing accuracy of the defects. The corrosion behavior was closely correlated to the tube noise measured using a rotating probe, while it was not related to the noise measured using a bobbin probe. It is suggested that the tube noise value measured using a rotating pancake coil probe can be a decisive measure to estimate the corrosion behavior of tubing

  16. Nondestructive Examination of Ferromagnetic Tube Using Magnetic Saturation Eddy Current Technique

    International Nuclear Information System (INIS)

    The tubes in heat exchanger are typically made from copper alloy, stainless steel, carbon steel, titanium alloy material. Type-439 ferritic stainless steel is ferromagnetic material, and furnish higher heat transfer rates than austenitic stainless steels and higher resistance to corrosion-induced flaws. Ferritic stainless steel can typically be found in low-pressure(LP) feedwater heaters and moisture separator reheaters(MSRs). LP feedwater heaters generally utilize thin wall type-439 stainless steel tubing, whereas MSRs typically employ a heavier wall tubing with integral fins. Service-induced damage can occur on the OD(outside diameter) surface of type-439 ferritic stainless steel tubing which is employed for MSRs tubing, and the most typical damage mechanism is vibration-induced tube-to-TSP(tube support plate) wear and fatigue cracking. The wear has been reported that occurs mainly on the OD surface. Accordingly, in this study, we have evaluated the flaw sizing capability of magnetic saturation eddy current technique using magnetic saturation probe and flawed specimen

  17. Correlation between General Corrosion Behavior and Eddy Current Noise of Alloy 690 Steam Generator Tube

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Do Haeng; Choi, Myung Sik; Lee, Deok Hyun; Shim, Hee-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Nickel and its oxides are released from the surface of steam generator tubes into the primary water. Released nickel and cobalt is activated to Co-58 and Co-60 in the reactor core by a neutron flux, respectively. These activated corrosion products are the main source of high radiation fields and occupational radiation exposure. In addition, some of the corrosion products redeposit on the fuel cladding, hinder the heat transfer, increase the corrosion rate of the fuel cladding, and finally induce an axial offset anomaly. This phenomenon can decrease core shutdown margin, and thus lead to a down-rating of a plant. Recently, many researchers have reported that the surface states of Alloy 690 tubes affect the corrosion product formation and its release in simulated primary water environments. Meanwhile, the surface states of steam generator tubes affect the noise level of eddy current testing. Noise signals arising from the tubes degrade the probability of detection and sizing accuracy of the defects. The corrosion behavior was closely correlated to the tube noise measured using a rotating probe, while it was not related to the noise measured using a bobbin probe. It is suggested that the tube noise value measured using a rotating pancake coil probe can be a decisive measure to estimate the corrosion behavior of tubing.

  18. Evaluation of an adaptive filtering algorithm for CT cardiac imaging with EKG modulated tube current

    Science.gov (United States)

    Li, Jianying; Hsieh, Jiang; Mohr, Kelly; Okerlund, Darin

    2005-04-01

    We have developed an adaptive filtering algorithm for cardiac CT scans with EKG-modulated tube current to optimize resolution and noise for different cardiac phases and to provide safety net for cases where end-systole phase is used for coronary imaging. This algorithm has been evaluated using patient cardiac CT scans where lower tube currents are used for the systolic phases. In this paper, we present the evaluation results. The results demonstrated that with the use of the proposed algorithm, we could improve image quality for all cardiac phases, while providing greater noise and streak artifact reduction for systole phases where lower CT dose were used.

  19. Evaluation of the eddy-current method of inspecting steam generator tubing

    International Nuclear Information System (INIS)

    The objective of this project has been to evaluate the eddy-current method of inspecting steam generator tubing by conducting a series of laboratory experiments with conventional eddy-current equipment. The experiments have involved obtaining eddy-current measurements on samples of 7/8-inch OD Inconel-600 tubing provided by the Westinghouse Nuclear Energy Systems Division. A variety of machined defects and some chemically induced flaws, such as stress corrosion cracks were fabricated in the tubing. Statistical evaluation of the data was employed to estimate the error encountered in measuring corrosion defects of various depths. It appears that the eddy-current technique can provide a reasonable measure of defect depth under certain conditions. On the other hand, the evaluation indicates that it is difficult to determine the depth of certain types of flaws with reliability and precision. Furthermore, although some defects as shallow as 10 percent of the tube wall could be detected, it was not possible to detect other types of flaws that were less than 40 percent deep even when the tube supports were not near the defects. The difficulty in detecting small volume flaws is attributed to low signal-to-noise ratio. Noise is a result of unwanted signals from test variables, such as wobble and variations in tube properties. The error in measurement of certain types of larger defects is associatedin part with test variables and also with the effects that the geometry of the defect has on the eddy-current signal patterns. The distortions in signal patterns caused by gradual wastage type defects and the poor reproducibility of signal patterns obtained from notches that represent stress corrosion cracks are described. Some developments that will rectify these detection and depth measurement problems are discussed

  20. Eddy Currents Inspection of CANDU Steam Generators' Tubes using Zetec's ZR-1 Robot. Experience in Romania

    International Nuclear Information System (INIS)

    This is a PowerPoint presentation on behalf of COMPCONTROL ING, a Romanian private company established in 1997 the main services of which are enlisted. It is stressed that the most suitable type of inspection in terms of safety and reliability for the steam generator tubes is eddy current (EC) method. The advantages of EC testing include the following: - Extremely fast; - Accurate in detection and sizing of discontinuities; - Very good method for baseline screening; - Very high detection sensitivity to physical-chemical variations of the test specimen; - Easy setup and application for automated inspection; - Portable equipment designing; - Use of multiple channels and multi-frequencies for a better screening of signals and efficiency; - High capability to store the data for future review and comparison (using data history to evaluate the rate of degradation and life assessment studies). Between 2003 and 2005 ECT was applied to Cernavoda NPP U1 SGs as follows: - in 2003, SG-4; - in 2004, SG-2; - in 2005, SG-1; - in 2005, SG-3; - in 2005, SG-4. The purpose of inspection with eddy currents of SGs tubes was: - Detection, sizing and evaluation of possible degradations of the tubes and at the interface tube/support structures (tubesheet, tube support plates and baffles); - Completion of the baseline data for future review and comparison. The software used for acquisition and analysis of eddy current data and for inspection management were: - ZETEC Eddynet-R Zetec Acquisition Control-ZAC; - ZETEC Eddynet-R Data Analysis (bobbin and MRPC); - ZETEC Eddynet-R Data Management. The equipment ZR-1 is described and its advantages as well. Advantages of the automated scanning system are highlighted as follows: - Repeatability; - High resolution mapping; - Accurate indexing; - Minimize changes in lift-off resulting from probe wobble, eccentricity of the tube and surface irregularities; - 3-part design makes each component lighter and more compact for easier, faster installation

  1. Bi2212 HTS bulk tubes prepared by the diffusion process for current lead application

    International Nuclear Information System (INIS)

    Bi2212 HTS tubular bulk conductors have been prepared by the diffusion process for current lead application. The Bi2212 HTS layers are synthesized through the diffusion reaction between a Sr-Ca-Cu oxide substrate and a Bi-Cu oxide coating with Ag addition. Two different shaped substrates were prepared. The former substrates are formed into the cylindrical tubes 30 mm in outside diameter and 200 mm in length by cold isostatic pressing, and then sintered. The latter ones are the conical tubes with larger end of 30-40 mm and smaller end of 20 mm in diameter. The transport current of the specimen depends on the cross-sectional area of Bi2212 layers, and varies from 4000 to 8000 A at 4.2 K, which corresponds to the current density of about 2-3 x 104 A/cm2 for the Bi2212 layer. The transport current decreases with increasing temperature at the warm end of the specimen, which is, for example, about 3200 A at 40 K or 2000 A at 50 K. The total heat loads composed of heat leakage conducted through the tube between the warm joint and the cold joint at 4.2 K, and of Joule heating at the cold joint are estimated. Present Pb-free Bi2212 HTS bulk tubes seem to be promising for large transport current leads with small heat loads for superconducting magnets

  2. Diagnostic of corrosion defects in steam generator tubes using advanced signal processing from Eddy current testing

    International Nuclear Information System (INIS)

    Recently, the Brazilian Angra I PWR nuclear power plant went into a programmed shutdown for substitution of its Steam Generator (SG) which life was shortened due to stress corrosion in its tubes. The total cost of investment were around R$724 million. The signals generated during an Eddy-current Testing (ECT) inspection in SG tubes of nuclear plant allows for the localization and dimensioning of defects in the tubes. The defects related with corrosion generate complex signals that are difficult to analyze and are the most common cause in SG replacement in nuclear power plants around the world. The objective of this paper is the development of a methodology that allows for the characterization of corrosion signals by ECT inspections applied in the heat exchangers tubes of SG of a nuclear power plant. In this present work, the aim is to investigate distributed type defects by inducing controlled corrosion in sample tubes of different materials The ECT signals obtained from these samples tubes with corrosion implanted, will be analyzed using Zetec ECT equipment, the MIZ-17ET and its probes. The data acquisition will use a NI PC A/D CARD 700 card and the LabVIEW program. Subsequently, we will apply mathematical tools for signal processing like time windowed Fast Fourier transforms and Wavelets transforms, in MATLAB platform, which will allow effectiveness to remove the noises and to extract representative characteristics for the defect being analyzed. Previously obtained results as well as the proposal for the future work will be presented. (author)

  3. [An automatic torque control system for a bicycle ergometer equipped with an eddy current brake].

    Science.gov (United States)

    Kikinev, V V

    2007-01-01

    The main elements of the loading device of a bicycle ergometer, including an eddy current brake and a torque sensor, are described. The automatic torque control system, which includes the loading device, is equipped with a stabilizing feedback controller that optimally approximates the closed-loop transfer function of the target model. The reduced transfer function model of the controller is of the fourth order. A method featuring a modulation-demodulation loop is suggested for implementation of the control system. PMID:17598478

  4. Ultrasound testing of the penetration of automatic welds of tubes on plates with using electron beams

    International Nuclear Information System (INIS)

    This control technique was developed within the scope of a D.G.R.S.T. study on electron beam welding of tubes to exchanger plates with a portable gun. The device developed is easy to use and enables the control to be carried out according to various techniques with good accuracy: used for acceptance tests merely for testing that a penetration to specification is reached and by working by 'hit and miss', it permits high work rates; used as a quality control system, it enables recordings to be made which accurately record the shape of the weld bead root, the penetration depth (and any possible weld compactness faults). The work rate is then reduced. Of course, the combined use of both techniques is possible, even advisable in some cases. For example, it is possible to imagine a total control by the first technique and an additional exploration by the second one. The exploration can then be to a percentage fixed by agreement or better, form a supplementary examination orientated according to the results obtained during the short examination

  5. Equivalency assessment for an eddy current system used for steam generator tubing inspection

    International Nuclear Information System (INIS)

    Eddy current testing is widely used for inspecting steam generator tubing in nuclear power plants (NPPs). The inspection technique for steam generator tubing in NPPs should be qualified in accordance with examination guidelines. When the components of a qualified system such as eddy current tester, probe, and data analysis program, are changed, the equivalency of the modified system to the originally qualified system must be verified. The eddy current tester is the most important part of an eddy current testing system because it excites and transmits alternating currents to the probe, receives coil impedance of the probe and generates signals for anomalies. The Korea Hydro and Nuclear Power Co., Ltd. (KHNP) developed an eddy current testing system with an eddy current tester and data acquisition-analysis program for inspecting the steam generator tubing in NPPs; this system can be used for an array probe and as a bobbin and rotating probes. The equivalency assessment for the currently developed system was carried out, and we describe the results in this paper

  6. Equivalency assessment for an eddy current system used for steam generator tubing inspection

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chan Hee; Lee, Tae Hun; Yoo, Hyun Ju; Moon, Gyoon Young [Korea Hydro and Nuclear Power Company Ltd., Central Research Institute, Daejeon (Korea, Republic of)

    2015-08-15

    Eddy current testing is widely used for inspecting steam generator tubing in nuclear power plants (NPPs). The inspection technique for steam generator tubing in NPPs should be qualified in accordance with examination guidelines. When the components of a qualified system such as eddy current tester, probe, and data analysis program, are changed, the equivalency of the modified system to the originally qualified system must be verified. The eddy current tester is the most important part of an eddy current testing system because it excites and transmits alternating currents to the probe, receives coil impedance of the probe and generates signals for anomalies. The Korea Hydro and Nuclear Power Co., Ltd. (KHNP) developed an eddy current testing system with an eddy current tester and data acquisition-analysis program for inspecting the steam generator tubing in NPPs; this system can be used for an array probe and as a bobbin and rotating probes. The equivalency assessment for the currently developed system was carried out, and we describe the results in this paper.

  7. Feasibility of low-concentration iodinated contrast medium with lower-tube-voltage dual-source CT aortography using iterative reconstruction: comparison with automatic exposure control CT aortography.

    Science.gov (United States)

    Shin, Hee Jeong; Kim, Song Soo; Lee, Jae-Hwan; Park, Jae-Hyeong; Jeong, Jin-Ok; Jin, Seon Ah; Shin, Byung Seok; Shin, Kyung-Sook; Ahn, Moonsang

    2016-06-01

    To evaluate the feasibility of low-concentration contrast medium (CM) for vascular enhancement, image quality, and radiation dose on computed tomography aortography (CTA) using a combined low-tube-voltage and iterative reconstruction (IR) technique. Ninety subjects underwent dual-source CT (DSCT) operating in dual-source, high-pitch mode. DSCT scans were performed using both high-concentration CM (Group A, n = 50; Iomeprol 400) and low-concentration CM (Group B, n = 40; Iodixanol 270). Group A was scanned using a reference tube potential of 120 kVp and 120 reference mAs under automatic exposure control with IR. Group B was scanned using low-tube-voltage (80 or 100 kVp if body mass index ≥25 kg/m(2)) at a fixed current of 150 mAs, along with IR. Images of the two groups were compared regarding attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), iodine load, and radiation dose in various locations of the CTA. In comparison between Group A and Group B, the average mean attenuation (454.73 ± 86.66 vs. 515.96 ± 101.55 HU), SNR (25.28 ± 4.34 vs. 31.29 ± 4.58), and CNR (21.83 ± 4.20 vs. 27.55 ± 4.81) on CTA in Group B showed significantly greater values and significantly lower image noise values (18.76 ± 2.19 vs. 17.48 ± 3.34) than those in Group A (all Ps < 0.05). Homogeneous contrast enhancement from the ascending thoracic aorta to the infrarenal abdominal aorta was significantly superior in Group B (P < 0.05). Low-concentration CM and a low-tube-voltage combination technique using IR is a feasible method, showing sufficient contrast enhancement and image quality. PMID:26621755

  8. Analysis of pulsed eddy current data using regression models for steam generator tube support structure inspection

    Science.gov (United States)

    Buck, J. A.; Underhill, P. R.; Morelli, J.; Krause, T. W.

    2016-02-01

    Nuclear steam generators (SGs) are a critical component for ensuring safe and efficient operation of a reactor. Life management strategies are implemented in which SG tubes are regularly inspected by conventional eddy current testing (ECT) and ultrasonic testing (UT) technologies to size flaws, and safe operating life of SGs is predicted based on growth models. ECT, the more commonly used technique, due to the rapidity with which full SG tube wall inspection can be performed, is challenged when inspecting ferromagnetic support structure materials in the presence of magnetite sludge and multiple overlapping degradation modes. In this work, an emerging inspection method, pulsed eddy current (PEC), is being investigated to address some of these particular inspection conditions. Time-domain signals were collected by an 8 coil array PEC probe in which ferromagnetic drilled support hole diameter, depth of rectangular tube frets and 2D tube off-centering were varied. Data sets were analyzed with a modified principal components analysis (MPCA) to extract dominant signal features. Multiple linear regression models were applied to MPCA scores to size hole diameter as well as size rectangular outer diameter tube frets. Models were improved through exploratory factor analysis, which was applied to MPCA scores to refine selection for regression models inputs by removing nonessential information.

  9. Examination of coiled steam-generator tubes by the multifrequency eddy current method

    International Nuclear Information System (INIS)

    If a generator tube in a fast-neutron breeder reactor is perforated, there could follow a violent water-sodium reaction which may damage the tubes in the vicinity. To reduce this risk it is necessary to detect any wastage of tube thickness and assess its severity. In the French fast-reactor design each of the tubes to be examined is in the form of a coil with an entry loop at the top and an expansion loop at its lower extremity. The length of the whole, which is composed of several sections assembled by means of butt welds, is about 100m. The coils are wound round an inert core and held in place by clips and toothed support devices. There are two main problems, (a) how to insert a probe into a coiled tube; (b) how to make an effective measurement by the eddy current technique in view of the many disturbing factors present. The first is overcome by using the Discault apparatus described here. The second can be overcome by eddy currents analysis at different frequencies and then using different combinations of the signals to reduce the number of disturbing factors. (U.K.)

  10. Induced fermionic current by a magnetic tube in the cosmic spacetime

    CERN Document Server

    de Sousa, M S Maior; de Mello, E R Bezerra

    2015-01-01

    In this paper, we consider a charged massive fermionic quantum field in the space-time of an idealized cosmic string, in the presence of a magnetic field confined in a cylindrical tube of finite radius. Three distinct configurations for the magnetic field is taken into account: (i) a cylindrical shell of radius $a$, (ii) a magnetic field proportional to $1/r$ and (iii) a constant magnetic field. In these three cases, the axis of the infinitely long tube of radius $a$ coincides with the cosmic string. Our main objective is to analyze the induced vacuum fermionic current densities outside the tube. In order to do that, we explicitly construct the wave-functions inside and outside the tube for each case. Having the complete set of normalized wave-functions, we use the summation method to develop our analysis. We show that in the region outside the tube, the induced currents are decomposed into a parts corresponding to a zero-thickness magnetic flux in addition to a core-induced contributions. The latter presents...

  11. Enhancement of the Remote Field Eddy Current Testing Performed from Outside of a Magnetic Tube

    OpenAIRE

    Tomas Marek; Daniela Gombarska

    2006-01-01

    The paper deals with design of remote field eddy current probe for non-destructive testing dedicated for inspection of ferromagnetic tubular material from outside. The remote field effect inside the tube wall is achieved by the medium of a magnetic shield covering the probe. Results of numeric simulations made for verification of probe characteristics confirmed the effectiveness of probe design.

  12. Evaluation of Semi-Automatic Metadata Generation Tools: A Survey of the Current State of the Art

    OpenAIRE

    Park, Jung-ran; Brenza, Andrew

    2015-01-01

    Assessment of the current landscape of semi-automatic metadata generation tools is particularly important considering the rapid development of digital repositories and the recent explosion of big data. Utilization of (semi)automatic metadata generation is critical in addressing these environmental changes and may be unavoidable in the future considering the costly and complex operation of manual metadata creation. To address such needs, this study examines the range of semi-automatic metadata...

  13. Finite element analysis for differential eddy current probe design of steam generator tubes

    International Nuclear Information System (INIS)

    Eddy current non-destructive evaluation technique is one of the most useful electromagnetic methods for early detection of defects in critical nuclear components such as steam generator tubes, fuel rod and turbine disk, etc. For the better analysis of eddy current signal measured from experiment for awkward shape of defect, numerical modelling analysis is very important in understanding the physics of electromagnetic field/defect interactions. In this study, A two-dimensional magnetic vector potential finite element formation for the modeling of eddy current non-destructive evaluation phenomena is described. The technique is illustrated by predicting differential eddy current probe impedance plane trajectories for change of coil distance and coil size in PWR steam generator tubing

  14. Finite element analysis of Eddy-Current nondestructive evaluation for steam generator tubes

    International Nuclear Information System (INIS)

    Eddy current non-destructive evaluation technique is one of the most useful electromagnetic methods for early detection of detects in critical nuclear components such as steam generator tubes, fuel rod and turbine disk, etc. For the better analysis of eddy current signal measured from experiment for awkward shape of defect, numerical modeling analysis is very important in understanding the physics of electromagnetic field/defect interactions. In this study, a two-dimensional magnetic vector potential finite element formation for the modeling of eddy current non-destructive evaluation phenomena is described. The technique is illustrated by predicting differential eddy current probe impedance plane trajectories for various defects in PWR steam generator tubes

  15. Combined leakage flux and eddy current examination system for the inspection of steel tubes

    International Nuclear Information System (INIS)

    A combination of flux leakage and eddy current units ultrasonic wall thickness and optical diameter gauges leads to an economic and reliable system. The solution of problems related to the calibration, signal evaluation and condition monitoring of multi-channel systems is found in computer-supported systems including the digital control of mechanical driving devices. The use of a computerized central controller allows rather high comfort in evaluation and signal processing and presentation. This solution applied to a special class of tubing shows us the way to go further in the field of conventional 4-function oil field tube inspection systems. (orig./RW)

  16. Particular treatments in Eddy current technique. Application to the control of corrugated tubes

    International Nuclear Information System (INIS)

    When the testing of a given product shows that, owing to a particular shape of this product or to its environment, disturbing effects can hide the presence of harmful defects, use must be made of testing artifices or particular treatments enabling an efficient examination to be made. On this score, many eddy current problems are solved by means of the following processes: - use of specific sensors adapted to the geometry of the product, - spectral analysis of the analog results of analyses, - combination of the results of analyses obtained simultaneously at different frequencies (multifrequency techniques). An example of an application is given for corrugated tubes achieved by hollow and helical milling of smooth tubes

  17. Shape of the current tube of a negative point-to-plane corona in air

    International Nuclear Information System (INIS)

    Results are presented from the experimental studies of a negative point-to-plane air corona discharge with controlled geometry. It is shown that, in a certain range of parameters, the steady-state current-voltage characteristic of the corona can be fitted by a parabola. The results obtained are used to determine the time-averaged shape of the current tube of a negative corona

  18. Current-driven vortex domain wall motion in wire-tube nanostructures

    Science.gov (United States)

    Espejo, A. P.; Vidal-Silva, N.; López-López, J. A.; Goerlitz, D.; Nielsch, K.; Escrig, J.

    2015-03-01

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  19. Current-driven vortex domain wall motion in wire-tube nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Espejo, A. P. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Vidal-Silva, N. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); López-López, J. A. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Goerlitz, D.; Nielsch, K. [Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, 9170124 Santiago (Chile)

    2015-03-30

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  20. Phenomenological modeling of eddy current signals with a view to characterizing steam generator tube flaws

    International Nuclear Information System (INIS)

    This work deals with the eddy current non-destructive test ing. Its long-term goal is to design an 'inverse model' for evaluating the geometry an d the dimensions of steam generator tube flaws from eddy current signals. The approach we adopted requires the preliminary knowledge of a 'forward model' that estimates the eddy current signal knowing the geometry and the dimensions of the flaws. A quasi-exhaustive study of the existing forward models showed their inadequacy to solve the inverse problem. Hence, we proposed to build a general forward model, appropriate to the inversion. Using a parametric approach, this model is phenomenological, i.e. it is based on observations made from results of a finite element code. For each position of the coil, the proposed forward model fist discretized the eddy current distribution into 'tubes of current'. A parametric description of the shape of these tubes is given according the system constituted of the coil and the tubes of current as a 'multi-transformer', their current signal, can then be deduced. The model was validated in the case of an axisymmetric configuration. Comparisons with both analytical and numerical models showed very good agreements. Then, the proposed model was applied to a three-dimensional configuration. Comparisons with experimental results are sufficiently conclusive to validate the approach to the construction of the phenomenological model. However, before envisaging the inverse problem, the computation time, still too long, ought to be reduced and the parametric description needs to be generalized to other three-dimensional configurations. (author)

  1. Transmit-receive eddy current probes for circumferential cracks in heat exchanger tubes

    International Nuclear Information System (INIS)

    Conventional eddy current bobbin probes are known to be ineffectual in detecting circumferential cracks in tubing. Multi-pancake and/or rotating pancake probes are required to detect circumferential cracks. It has recently been demonstrated in CANDU steam generator tubes, with deformation, ferromagnetic deposits, and copper deposits, that multi-channel probes with transmit-receive (T/R) coils are superior to those using surface impedance coils. Unlike rotating probes, the design of a new probe denoted as C3 permits fast, single-scan inspection of a full-length tube at inspection speeds comparable to conventional bobbin probes. Since 1992, the probe has been used routinely for steam generator in-service inspection at 4 CANDU plants. Defective tubes have been plugged and the units returned to service, and they continue to operate without leaks. This paper describes the basic features of T/R surface probes. Two-dimensional voltage diagrams showing computer-derived probe response to frequency, lift-off, carbon steel supports, magnetite deposits and copper deposits are presented and compared with corresponding signals from impedance coils. Theoretical and experimental results show that T/R probes are able to detect defects in the presence of variable lift-off (due to tube-wall deformation) with ten times the signal-to-noise ratio as that exhibited by comparable pancake-type impedance probes. In addition, T/R probes are less sensitive to magnetite deposits, and possess good phase discrimination to internal defects

  2. The effects of ID magnetite deposits on steam generator tube eddy current signals

    International Nuclear Information System (INIS)

    The presence of primary-side magnetite deposits in CANDU steam generator tubes poses a significant challenge to the analysis of eddy current inspection data. In principle, magnetite shields the tubing from the eddy current probe, diminishing its sensitivity to flaws. Since a probe's flaw detection and sizing performance is typically assessed with the use of clean laboratory samples, the shielding effect can become significant enough to affect both the probability of detection (POD) and sizing accuracy of the probe. Hence, there is a need to understand the relationship between inside diameter (ID) magnetite fouling and the actual flaw signals from typical flaws, such as pitting corrosion and fretting wear. The studies presented in this paper were performed with bobbin and X-probe data in both Inconel 600 and Incoloy 800 tubing. In comparison with clean tubes, ID deposits have a definite impact on both the detection and sizing capabilities of each probe. In all cases, the flaw signal amplitudes tend to decrease with increasing amounts of ID magnetite fouling. This also causes the probes to undersize the flaws in the fouled tubes. The resulting effect can be expressed in terms of a reduction factor versus a measured quantity with the bobbin probe, called Vshield, which can be used to determine the correction factor for sizing flaws. Given the difficulty in controlling the error sources in laboratory experiments on field-pulled tubes with deposits, the resulting scatter in the data makes the extraction of useful relationships between fouling and flaw signals difficult. This paper, therefore, presents an approach that consists of a combination of computer modelling, laboratory experiments on pulled tube samples, and field-data analysis to allow trends and relationships to be developed for a range of ID magnetite loading and thickness beyond that available in pulled tubes. A 3D electromagnetic finite element model was developed for studying the effects of ID magnetite

  3. Transmit-receive eddy current probes for defect detection and sizing in steam generator tubes

    International Nuclear Information System (INIS)

    Inspection of steam generator tubes in aging Nuclear Generating Stations is increasingly important. Defect detection and sizing, especially in defect prone areas such as the tubesheet, support plates and U-bend regions, are required to assess the fitness-for-service of the steam generators. Information about defect morphology is required to address operational integrity issues, i.e., risk of tube rupture, number of tubes at risk, consequential leakage. A major challenge continues to be the detection and sizing of circumferential cracks. Utilities around the world have experienced this type of tube failure. Conventional in-service inspection, performed with eddy current bobbin probes, is ineffectual in detecting circumferential cracks in tubing. It has been demonstrated in CANDU steam generators, with deformation, magnetite and copper deposits that multi-channel probes with transmit-receive eddy current coils are superior to those using surface impedance coils. Transmit-receive probes have strong directional properties, permitting probe optimization according to crack orientation. They are less sensitive to lift-off noise and magnetite deposits and possess good discrimination to internal defects. A single pass C3 array transmit-receive probe developed by AECL can detect and size circumferential stress corrosion cracks as shallow as 40% through-wall. Since its first trial in 1992, it has been used routinely for steam generator in-service inspection of four CANDU plants, preventing unscheduled shutdowns due to leaking steam generator tubes. More recently, a need has surfaced for simultaneous detection of both circumferential and axial cracks. The C5 probe was designed to address this concern. It combines transmit-receive array probe technology for equal sensitivity to axial and circumferential cracks with a bobbin probe for historical reference. This paper will discuss the operating principles of transmit-receive probes, along with inspection results

  4. Transmit-receive eddy current probes for defect detection and sizing in steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Obrutsky, L.S.; Cecco, V.S.; Sullivan, S.P. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    1997-02-01

    Inspection of steam generator tubes in aging Nuclear Generating Stations is increasingly important. Defect detection and sizing, especially in defect prone areas such as the tubesheet, support plates and U-bend regions, are required to assess the fitness-for-service of the steam generators. Information about defect morphology is required to address operational integrity issues, i.e., risk of tube rupture, number of tubes at risk, consequential leakage. A major challenge continues to be the detection and sizing of circumferential cracks. Utilities around the world have experienced this type of tube failure. Conventional in-service inspection, performed with eddy current bobbin probes, is ineffectual in detecting circumferential cracks in tubing. It has been demonstrated in CANDU steam generators, with deformation, magnetite and copper deposits that multi-channel probes with transmit-receive eddy current coils are superior to those using surface impedance coils. Transmit-receive probes have strong directional properties, permitting probe optimization according to crack orientation. They are less sensitive to lift-off noise and magnetite deposits and possess good discrimination to internal defects. A single pass C3 array transmit-receive probe developed by AECL can detect and size circumferential stress corrosion cracks as shallow as 40% through-wall. Since its first trial in 1992, it has been used routinely for steam generator in-service inspection of four CANDU plants, preventing unscheduled shutdowns due to leaking steam generator tubes. More recently, a need has surfaced for simultaneous detection of both circumferential and axial cracks. The C5 probe was designed to address this concern. It combines transmit-receive array probe technology for equal sensitivity to axial and circumferential cracks with a bobbin probe for historical reference. This paper will discuss the operating principles of transmit-receive probes, along with inspection results.

  5. Interpolation method for calculation of computed tomography dose from angular varying tube current

    International Nuclear Information System (INIS)

    The scope and magnitude of radiation dose from computed tomography (CT) examination has led to increased scrutiny and focus on accurate dose tracking. The use of tube current modulation (TCM) results complicates dose tracking by generating unique scans that are specific to the patient. Three methods of estimating the radiation dose from a CT examination that uses TCM are compared: using the average current for an entire scan, using the average current for each slice in the scan, and using an estimation of the angular variation of the dose contribution. To determine the impact of TCM on the radiation dose received, a set of angular weighting functions for each tissue of the body are derived by fitting a function to the relative dose contributions tabulated for the four principle exposure projections. This weighting function is applied to the angular tube current function to determine the organ dose contributions from a single rotation. Since the angular tube current function is not typically known, a method for estimating that function is also presented. The organ doses calculated using these three methods are compared to simulations that explicitly include the estimated TCM function. (authors)

  6. Eddy current monitoring of fatigue crack growth in Zr-2.5% Nb pressure tube

    Science.gov (United States)

    Krause, T. W.; Martin, A. E.; Sheppard, R. R.; Schankula, J. J.

    2000-05-01

    Zr-2.5% wt. Nb pressure tubes (PTs) form the core of the heat transport system in CANDU nuclear reactors. These 6 m long, 100 mm diameter tubes are operated at elevated temperatures (nominally 300 °C) and at pressures that produce hoop stresses that are 25% of the ultimate tensile strength of the PT (120 Mpa). Therefore, detection and characterization of flaws in these components becomes crucial for their continued pressure retaining integrity. If a flaw is detected, however, the cost of PT replacement is expensive. Periodic in-service inspection of a flaw that demonstrates no change in flaw characteristics can be used to allow a pressure tube to remain in-service. This requires confidence in the accuracy and reliability of methods used to inter flaw characteristics. Such confidence can only be developed by comparing nondestructive predictions with results from destructive examinations. In this work, eddy current testing was used to monitor the progressive stages of a fatigue crack, grown through pressure cycling from a notch on the inner surface of a PT. Results from a differential lift-off compensated eddy current probe were used to produce sizing estimates of the crack grown between 35% (base of notch) and 74% of the PT wall. A comparison with a destructive examination of the crack demonstrated sensitivity too changes in crack depth accurate to 5% of the tube wall thickness. Such results, combined with similar information obtained from ultrasonics will increase confidence in interpretation of PT inspection data.

  7. On the Full-automatic Forming Technologies of S31803 Duplex Seamless Steel Tube%S31803双相无缝钢管全自动成型关键技术研究

    Institute of Scientific and Technical Information of China (English)

    章迪康; 孙作龙

    2013-01-01

    S31803 duplex stainless steel dominates the seamless steel tube market and has an increasingly output, for its struc-ture both has austenite and ferrite;it has the advantages of austenite steel and ferrite steel in function. But the stricter requirement and the weakness in forming process affect its promotion. Through such key technologies in full-automatic forming as online narrow gap automatic welding, online automatic cutting and slender thin wall polishing, succeed in developing full-automatic forming equipment of S31803 duplex and high pressure resistant seamless steel tube, solve the technical bottleneck of full-automatic forming in seamless steel tube.%  S31803双相不锈钢的组织结构既有奥氏体又有铁素体,在性能上兼具奥氏体不锈钢和铁素体不锈钢的优点,占据无缝钢管领域主导地位,但因产品要求更加严格及存在着成型工艺上的弱势而影响了推广使用。通过在线窄焊缝自动焊接、在线自动切割、细长薄壁管内抛光等全自动成型的关键技术研究,成功研发了S31803双相耐高压无缝钢管全自动成型设备,解决了无缝钢管全自动成型的技术瓶颈。

  8. Finite element analysis of differential eddy current probe signal with steam generator tubes

    International Nuclear Information System (INIS)

    Electromagnetic methods(eddy current technique) of nondestructive testing are widely used in various industries for characterization of materials and detection of flaws. These methods are based on measurable changes in the electrical and magnetic properties(conductivity and permeability) of materials caused by the interaction with applied and induced fields. In this study, finite element analysis has been done to predict eddy current probe signal for steam generator tube containing a notch defect. The predicted eddy current signal is compared with experimental one.

  9. Sizing techniques for crack indications od eddy current data in steam generator tubes

    International Nuclear Information System (INIS)

    This paper describes the sizing methodology for stress corrosion cracking which lies in steam generator tubes. It is not easy to analyze exactly the depth and length of the crack from the eddy current data. The crack-sizing for the steam generator tube during the in-service inspection was not performed until July 2005 in Korea. However it is necessary to evaluate the depth and length of the crack in order to complete the condition monitoring and operational assessment of the Steam Generator Management Program. The currently available crack-sizing techniques were introduced from Electric Power Research Institute. Prior to applying to the field analysis, the round robin tests for those techniques were carried out by the domestic analysts. The results suggest that it is necessary to develop new techniques since the deviations for some types of crack are relatively large.

  10. Organ dose conversion coefficients for tube current modulated CT protocols for an adult population

    Science.gov (United States)

    Fu, Wanyi; Tian, Xiaoyu; Sahbaee, Pooyan; Zhang, Yakun; Segars, William Paul; Samei, Ehsan

    2016-03-01

    In computed tomography (CT), patient-specific organ dose can be estimated using pre-calculated organ dose conversion coefficients (organ dose normalized by CTDIvol, h factor) database, taking into account patient size and scan coverage. The conversion coefficients have been previously estimated for routine body protocol classes, grouped by scan coverage, across an adult population for fixed tube current modulated CT. The coefficients, however, do not include the widely utilized tube current (mA) modulation scheme, which significantly impacts organ dose. This study aims to extend the h factors and the corresponding dose length product (DLP) to create effective dose conversion coefficients (k factor) database incorporating various tube current modulation strengths. Fifty-eight extended cardiac-torso (XCAT) phantoms were included in this study representing population anatomy variation in clinical practice. Four mA profiles, representing weak to strong mA dependency on body attenuation, were generated for each phantom and protocol class. A validated Monte Carlo program was used to simulate the organ dose. The organ dose and effective dose was further normalized by CTDIvol and DLP to derive the h factors and k factors, respectively. The h factors and k factors were summarized in an exponential regression model as a function of body size. Such a population-based mathematical model can provide a comprehensive organ dose estimation given body size and CTDIvol. The model was integrated into an iPhone app XCATdose version 2, enhancing the 1st version based upon fixed tube current modulation. With the organ dose calculator, physicists, physicians, and patients can conveniently estimate organ dose.

  11. Development of eddy current examination techniques for steam generator ferromagnetic tubes in the LMFBR

    International Nuclear Information System (INIS)

    In the past, great efforts were made to improve the eddy current testing method as one of the techniques of the periodic examination of the steam generator tube in the liquid-metal fast breeder reactor (LMFBR). Because of the ferro-magnetic material used in the tube, the presence of the welded portion and the complicated configuration of the tube, its flaw detectability in the LMFBR steam generator tube was low compared with that in the pressurized water reactor (PWR). Attracted in part by the great advantage that it is easy to use in the periodic examination, we started to work progressively for the advancement of the testing technique six or seven years ago. An a result, we found it possible to increase the performance by incorporating a specific-shaped permanent magnet in testing probes and a signal processing method. And finally, the technique was so much improved that it could be put to practical use in detecting flaws except for crack-like flaws and flaws in the welded portion. In addition, we saw the way clear for detection of crack-like flaws and welded-portion flaws after carefully studying the shapes of testing probes. (author)

  12. Development of intelligent eddy current testing (ECT) system for PWR steam generator tube inspection

    International Nuclear Information System (INIS)

    Eddy Current Testing (ECT) system using the mutual induction method consists of one exiting coil and two detection coils. The performance of the system has the same inspection speed of ordinary total inspection probe and the detection ability of precision inspection probe. An analytical system with filtering processor and automatic analyzer for a large quantity of data was developed. The system was proved by the verification test of the Japan Power Engineering and Inspection Corporation (JAPEIC) in August 2003 and used by plant in January 2004. High performance intelligent ECT probe, probe with a built-in small analog electronic circuit, high performance flaw detector, automatic flaw detector system and the verification test are reported. (S.Y.)

  13. Distortions of Magnetic Flux Tubes in the Presence of Electric Currents

    Science.gov (United States)

    Malanushenko, Anna; Rempel, Matthias; Cheung, Mark

    2016-05-01

    Solar coronal loops possess several peculiar properties, which have been a subject of intensive research for a long time. These in particular include the lack of apparent expansion of coronal loops and the increased pressure scale height in loops compared to the diffuse background. Previously, Malanushenko & Schrijver (2013) proposed that these could be explained by the fact that magnetic flux tubes expand with height in a highly anisotropic manner. They used potential field models to demonstrate that flux tubes that have circular cross section at the photosphere, in the corona turn into a highly elongates structures, more resembling thick ribbons. Such ribbons, viewed along the expanding edge, would appear as thin, crisp structures of a constant cross-section with an increased pressure scale height, and when viewed along the non-expanding side, would appear as faint, wide and underdense features. This may also introduce a selection bias,when a set of loops is collected for a further study, towards those viewed along the expanding edge.However, some of the past studies have indicated that strong electric currents flowing in a given flux tube may result in the tube maintaining a relatively constant cross-sectional shape along its length. Given that Malanushenko & Schrijver (2013) focused on a potential, or current-free, field model of an active region, the extend to which their analysis could be applied to the real solar fields, was unclear.In the present study, we use a magnetic field created by MURaM, a highly realistic state-of-the-art radiative MHD code (Vogler et al, 2005; Rempel et al, 2009b). MURaM was shown to reproduce a wide variety of observed features of the solar corona (e.g., Hansteen et al, 2010; Cheung et al. 2007, 2008; Rempel 2009a,b). We analyze the distortions of magnetic flux tubes in a MURaM simulation of an active region corona. We quantify such distortions and correlate them with a number of relevant parameters of flux tubes, with a

  14. Multifrequency eddy current testing of steam generator tubes using optimal affine transformation

    International Nuclear Information System (INIS)

    An alternative technique was developed for the implementation of multifrequency/multiparameter concepts for extracting defect signal information from complex measured eddy current data. The approach uses affine transformations which appropriately shape and rotate the basic frequency response similar to procedures used in image registration. Vector subtraction of the auxiliary frequency signals is then performed to obtain the relevant eddy current defect signal. The mathematics of the technique are discussed. The experimental setup for reactor steam generator tube imaging is described and results are graphed

  15. Eddy current inspection of tubing; Inspeccion de tubos por corrientes de Foucault

    Energy Technology Data Exchange (ETDEWEB)

    Bauza, J. L. R.; Herrero, J.; Diaz, J.

    1966-07-01

    The Experimental research work carried out to develop a Eddy current testing equipment is described. Search coils with ferrite or air cores were used and the obtained results are discussed. Valuable information was gained from a improved channel in which a direct measure of the defect and the reference signal phase difference is obtained. Artificial defect used to evaluate resolution and sensitivity were produced by electro-machining and mechanical means. Finned SAP tubing was tested in a routine basis with the described equipment and the results plotted. Basic and theoretical considerations on the Eddy current testing technique are given in the last section of this report. (Author)

  16. A study on characteristic of glass dosimeter according to grade change of tube current

    International Nuclear Information System (INIS)

    This study was evaluated the linearity and reproducibility according to dose, and reproducibility according to delay time by changing tube current amount (5 mAs, 10 mAs, 16 mAs, 20 mAs, 25 mAs, 32 mAs respectively, which are low energy radiations) using Glass Dosimeter (GD) and piranha semiconductor dosimeter which are used for measuring exposure dose. Measurements of radiation dose were performed using external detector of piranha 657 which is multi-function QA device (RTI Electronic, Sweden). Conditions of measurement were 80 kVp, SSD 100 and exposure region is 10 cm x 10 cm. Glass dosimeter was exposed to radiation. Twenty-four glass dosimeters were divided into six groups (5 mAs, 10 mAs, 16 mAs, 20 mAs, 25 mAs, 32 mAs respectively), then measured. This study was resulted by measuring the linearity and reproducibility according to change of tube current in low energy field. In dose characteristic of GD, this study could be useful as previous study with regard to dose characteristic according to change of tube voltage in low energy field

  17. Automated inspection of pwr steam generator tubes with eddy current and ultrasonic techniques

    International Nuclear Information System (INIS)

    This paper reports that with a view to improve reactor safety and availability, the steam generator tubes of the seven Belgian nuclear plants are inspected, since 1985, with an automated non destructive examination system. Both eddy current and ultrasonic techniques are applied in function of the degradation phenomenon and the related plugging limit. The five years experience has shown that significant advantages in terms of increased accuracy and lower cost are related to the use of dedicated probes and a high level of automation. Owing to specialized data management, a preliminary field report is available one hour after the last tube has been inspected. Despite these capabilities, the inspection system uses commercially available instruments and desktop computers linked through a local area network. It demonstrates that improved inspection efficiency and low cost are achievable despite the use of sophisticated hardware and software in a nuclear environment

  18. Performance demonstration tests for eddy current inspection of steam generator tubing

    International Nuclear Information System (INIS)

    This report describes the methodology and results for development of performance demonstration tests for eddy current (ET) inspection of steam generator tubes. Statistical test design principles were used to develop the performance demonstration tests. Thresholds on ET system inspection performance were selected to ensure that field inspection systems would have a high probability of detecting and and correctly sizing tube degradation. The technical basis for the ET system performance thresholds is presented in detail. Statistical test design calculations for probability of detection and flaw sizing tests are described. A recommended performance demonstration test based on the design calculations is presented. A computer program for grading the probability of detection portion of the performance demonstration test is given

  19. Critical current density and stability of Tube Type Nb3Sn conductors

    Science.gov (United States)

    Sumption, M. D.; Bhartiya, S.; Kovacks, C.; Peng, X.; Gregory, E.; Tomsic, M. J.; Collings, E. W.

    2012-02-01

    The critical current densities (Jc) and stabilities of Tube Type Nb3Sn conductors have been measured. The strands had superconducting subelement counts ranging from 192 to 744, and flat-to-flat filament sizes (for 0.7 mm OD wire) of from 35 μm down to 15 μm. These Tube Type conductors had a very simple structure: prior to heat treatment the filaments consist of a Sn core surrounded by a thin Cu tube, itself surrounded by a Nb or Nb alloy tube. Eight different strand types were investigated using various techniques including SEM, residual resistance ratio (RRR), transport Jc, and stability measurement. Most strands were studied at 0.7 mm OD, with one representative at 0.42 mm. The transport measurements were made at 4.2 K in fields up to 14 T. Numerous heat treatment schedules were investigated, with reaction temperatures ranging from 615 °C to 650 °C, and times ranging from 36-500 h. The highest Jcs were seen for the lowest reaction temperatures, with 12 T transport Jc values as high as 2450 A/mm2 observed. The RRRs were lower for longer time and higher temperature reactions and ranged from 4 to 180. Strand stability was a strong function of the effective filament diameter, deff, and RRR. The most stable strands showed stability currents, Js, of 8700 A/mm2 and 15,300 A/mm2 for 0.7 mm OD and 0.42 mm OD conductors, respectively.

  20. Eddy current automatic inspection of heat exchangers in nuclear power stations

    International Nuclear Information System (INIS)

    This presentation describes the eddy current tube inspection techniques for heavy heat exchangers in nuclear power stations. The purpose of these eddy current tests, is first to determine the integrity of the heat exchanger tubes, and to characterize the related types of defects in each case following to their analysis and cause determination and subsequent inspection planning. This task requires a group highly qualified personnel with high tech automate equipment. The organization of the group required a correct function and task assignment in order to achieve efficiency in scheduling, with simultaneous inspection to different components in a continuous base and uninterruptedly. A lead specialist is in charge of the group, which is set up by several shift supervisors, a qualified tele manipulator installation crew a number of qualified tele manipulator operators, and the specialist for data acquisition and certified eddy current signal evaluators plus some other support technicians and administrations helpers. In order to comply with inspection requirements, a bunch of technical procedures had to be developed. The following equipment is available nowadays: Zetec SM-13, SM-23 and SM-22 tele manipulators for inspection probes positioning, with different shapes and configuration (rotating probes, flexible probes for U-Bends, and magnetic saturation probes endowed with their own driving units) and remote data acquisition units identified as MIZ-18 A and MIZ-30, which are remotely operated from a mobile lab installed in a trailer, outside the reactor building. The available equipment allows a simultaneous inspection of three different plant components (two steam generators and a moderator heat exchanger). We are also in a position of performing eddy current tube inspection in more than a NSP at the same time. The Zetec Eddynet software is used in the manipulator operation and for the data acquisition and defect evaluation. This software operates within Windows

  1. Monte Carlo simulations to assess the effects of tube current modulation on breast dose for multidetector CT

    OpenAIRE

    Angel, Erin; Yaghmai, Nazanin; Jude, Cecilia Matilda; Demarco, John J.; Cagnon, Christopher H.; Goldin, Jonathan G; Primak, Andrew N.; Stevens, Donna M.; Cody, Dianna D.; McCollough, Cynthia H.; McNitt-Gray, Michael F.

    2009-01-01

    Tube current modulation was designed to reduce radiation dose in CT imaging while maintaining overall image quality. This study aims to develop a method for evaluating the effects of tube current modulation (TCM) on organ dose in CT exams of actual patient anatomy. This method was validated by simulating a TCM and a fixed tube current chest CT exam on 30 voxelized patient models and estimating the radiation dose to each patient’s glandular breast tissue. This new method for estimating organ d...

  2. Modeling of tube current modulation methods in computed tomography dose calculations for adult and pregnant patients

    International Nuclear Information System (INIS)

    The comparatively high dose and increasing frequency of computed tomography (CT) examinations have spurred the development of techniques for reducing radiation dose to imaging patients. Among these is the application of tube current modulation (TCM), which can be applied either longitudinally along the body or rotationally along the body, or both. Existing computational models for calculating dose from CT examinations do not include TCM techniques. Dose calculations using Monte Carlo methods have been previously prepared for constant-current rotational exposures at various positions along the body and for the principle exposure projections for several sets of computational phantoms, including adult male and female and pregnant patients. Dose calculations from CT scans with TCM are prepared by appropriately weighting the existing dose data. Longitudinal TCM doses can be obtained by weighting the dose at the z-axis scan position by the relative tube current at that position. Rotational TCM doses are weighted using the relative organ doses from the principle projections as a function of the current at the rotational angle. Significant dose reductions of 15% to 25% to fetal tissues are found from simulations of longitudinal TCM schemes to pregnant patients of different gestational ages. Weighting factors for each organ in rotational TCM schemes applied to adult male and female patients have also been found. As the application of TCM techniques becomes more prevalent, the need for including TCM in CT dose estimates will necessarily increase. (author)

  3. Remote field eddy current technique for gap measurement of horizontal flux detector guide tube in pressurized heavy water reactor

    International Nuclear Information System (INIS)

    The fuel channels including the pressure tube(PT) and the calandria tube(CT) are important components of the pressurized heavy water reactor(PHWR). A sagging of fuel channel increases by heat and radiation exposure with the increasing operation time. The contact of fuel channel to the Horizontal flux Detector(HFD) guide tube is needed for the power plant safety. In order to solve this safety issue, the electromagnetic technique was applied to measure the status of the guide tube. The Horizontal flux Detector(HFD) guide tube and the Calandria tube(CT) in the Pressurized Heavy Water Reactor(PHWR) are cross-aligned horizontally. The remote field eddy current(RFEC) technology is applied for gap measurement between the HFD guide tube and the CT HFD guide tube can be detected by inserting the RFEC probe into pressure tube(PT) at the crossing point directly. The RFEC signals using the volume integral method(VIM) were simulated for obtaining the optimal inspection parameters. This paper shows that the simulated eddy current signals and the experimental results in variance with the CT/HFD gap.

  4. Finite element modeling of wall-loss sizing in a steam generator tube using a pulsed eddy current probe

    Science.gov (United States)

    Babbar, V. K.; Lepine, B.; Buck, J.; Underhill, P. R.; Morelli, J.; Krause, T. W.

    2015-03-01

    Inspection of steam generator (SG) tubes by conventional eddy current may, in general, involve analysis of indications from volumetric wall loss, cracks, fouling and support-plate degradation; however, it may be difficult to size or quantify effects from support-to-tube gap and tube tilt, especially in the presence of support plates. Pulsed eddy current (PEC) technology is being developed to investigate such complex tube and flaw geometries. The present work employs finite element modeling to investigate the effectiveness of PEC in identifying and sizing the outer diameter wall-loss in SG tubes. The signals analyzed using a modified principal components analysis (PCA) method reveal the potential success of a PEC-PCA combination to produce scores that can be used to size the wall-loss in the presence of support plates. The modeling results are in good agreement with experimental observations.

  5. The feasibility of a regional CTDIvol to estimate organ dose from tube current modulated CT exams

    International Nuclear Information System (INIS)

    Purpose: In AAPM Task Group 204, the size-specific dose estimate (SSDE) was developed by providing size adjustment factors which are applied to the Computed Tomography (CT) standardized dose metric, CTDIvol. However, that work focused on fixed tube current scans and did not specifically address tube current modulation (TCM) scans, which are currently the majority of clinical scans performed. The purpose of this study was to extend the SSDE concept to account for TCM by investigating the feasibility of using anatomic and organ specific regions of scanner output to improve accuracy of dose estimates. Methods: Thirty-nine adult abdomen/pelvis and 32 chest scans from clinically indicated CT exams acquired on a multidetector CT using TCM were obtained with Institutional Review Board approval for generating voxelized models. Along with image data, raw projection data were obtained to extract TCM functions for use in Monte Carlo simulations. Patient size was calculated using the effective diameter described in TG 204. In addition, the scanner-reported CTDIvol (CTDIvol,global) was obtained for each patient, which is based on the average tube current across the entire scan. For the abdomen/pelvis scans, liver, spleen, and kidneys were manually segmented from the patient datasets; for the chest scans, lungs and for female models only, glandular breast tissue were segmented. For each patient organ doses were estimated using Monte Carlo Methods. To investigate the utility of regional measures of scanner output, regional and organ anatomic boundaries were identified from image data and used to calculate regional and organ-specific average tube current values. From these regional and organ-specific averages, CTDIvol values, referred to as regional and organ-specific CTDIvol, were calculated for each patient. Using an approach similar to TG 204, all CTDIvol values were used to normalize simulated organ doses; and the ability of each normalized dose to correlate with patient size

  6. Exploring the useful exposure range limits of three intraoral image receptors for various tube potential, tube current and exposure time settings

    OpenAIRE

    Ioannis A. Tsalafoutas; Panagiotis Gritzalis; Evripides Stefanou; Evangelos Georgiou; Emmanouel Yakoumakis; Elli Katsoni

    2011-01-01

    Objectives: To determine the useful exposure range limits of three intraoral image receptors of different technology when exposed to different X-ray beam spectra, dose and dose rate levels. Study Design: A dental X-ray unit offering a wide range of tube potential, tube current and exposure time settings was used to expose a dental quality control phantom. The receptors that were used to capture the radiographic images of the phantom were: the Kodak Insight, the Kodak RVG-6000 and the Duerr Vi...

  7. Advanced eddy current technique for measurement of annular gap between pressure tube and calandria tube in Indian Pressurized Heavy Water Reactors (PHWRs)

    International Nuclear Information System (INIS)

    In Indian Pressurised Heavy Water Reactors (PHWRs), the PT (pressure tube) is designed to be nominally concentric with the encircling CT (calandria tube). Due to various factors PT becomes eccentric with respect to CT over the life of reactor. If this becomes excessive, hot PT will come in contact with cold CT. Such a cold spot could act as potential location for initiating blister formation and premature failure of PT. Hence it is important to periodically measure annular gap between PT and CT. An advanced eddy current technique has been successfully developed and incorporated in BARCIS (BARC Channel Inspection System) for measurement of PT-CT gap. (author). 4 refs., 3 figs

  8. The counter-current flooding limit in vertical tubes with and without orifices

    International Nuclear Information System (INIS)

    For hypothetical loss of coolant accidents in nuclear reactors, rapid reflooding of the core is desirable. In CANDU reactors the cooling water is injected into the headers which are connected to the fuel channels by the feeder pipes. These pipes consist of vertical and horizontal runs; in some feeders, orifices and/or venturi flow meters are installed for flow adjustments and measurements respectively. For certain postulated accident scenarios, steam coming from the fuel channels and/or generated in the hot feeders may flow in the direction opposite to that of the cooling water thereby, creating a vertical or horizontal counter-current two-phase flow. Under these conditions, the rate at which cooling water can enter the fuel channels may be limited by the flooding phenomena. This phenomena is greatly affected by the geometry of the feeder pips, shape and number of fittings, and the flow area restrictions located in the feeders. In this paper the influence that orifice type flow area restrictions have on the counter-current flooding limit (CCFL) in a vertical tube is examined. air and water at close to atmospheric conditions are used as the working fluids. The data collected on the counter-current flooding limit in a vertical tube both with and without flow area restrictions is compared against some of the most commonly used correlations that are available in the open literature. Data on the two-phase counter-current pressure drop below the flooding point are also presented. 12 refs., 10 figs., 1 tab

  9. Automatic orbital TIG-welding of small bore austenitic stainless steel tubes for nuclear fuel reprocessing plant

    International Nuclear Information System (INIS)

    Traditionally, manual welding techniques have been employed for shop and site fabrication of small bore austenitic stainless steel tubes in the nuclear fuel reprocessing plant of British Nuclear Fuels Limited (BNFL). This Paper describes an evaluation programme carried out to develop welding procedures for both 18Cr-13Ni-1Nb and 18Cr-10Ni low carbon stainless steel small bore tubing, the type of equipment used, and the modifications required for application to shop and site environments. (author)

  10. Improvement of ISI techniques by multi-frequency eddy current testing method for steam generator tube in PWR plant

    International Nuclear Information System (INIS)

    Eddy current flaw detection techniques are applied to the in-service inspection (ISI) of steam generator tubes in pressurized water reactors (PWR) plant. To improve the reliability and operating efficiency of the plants, efforts are being made to develop eddy current testing methods of various kinds. Multi-frequency eddy current testing method, one of new method, has recently been applied to actual heat exchanger tubes, contributing to the improvement of the detectability and signal evaluation of the ISI. The outline of multi-frequency eddy current testing method and its effects on the improvement of flaw detecting and signal evaluation accuracy are described. (author)

  11. A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes

    Science.gov (United States)

    Krause, T. W.; Babbar, V. K.; Underhill, P. R.

    2014-02-01

    Support plate degradation and fouling in nuclear steam generators (SGs) can lead to SG tube corrosion and loss of efficiency. Inspection and monitoring of these conditions can be integrated with preventive maintenance programs, thereby advancing station-life management processes. A prototype pulsed eddy current (PEC) probe, targeting inspection issues associated with SG tubes in SS410 tube support plate structures, has been developed using commercial finite element (FE) software. FE modeling was used to identify appropriate driver and pickup coil configurations for optimum sensitivity to changes in gap and offset for Alloy-800 SG tubes passing through 25 mm thick SS410 support plates. Experimental measurements using a probe that was manufactured based on the modeled configuration, were used to confirm the sensitivity of differential PEC signals to changes in relative position of the tube within the tube support plate holes. Models investigated the effect of shift and tilt of tube with respect to hole centers. Near hole centers and for small shifts, modeled signal amplitudes from the differentially connected coil pairs were observed to change linearly with tube shift. This was in agreement with experimentally measured TEC coil response. The work paves the way for development of a system targeting the inspection and evaluation of support plate structures in steam generators.

  12. Development and validation of a simulation tool dedicated to eddy current non destructive testing of tubes

    International Nuclear Information System (INIS)

    Eddy current testing (ECT) technique is widely used in industrial fields such as iron and steel industry. Dedicated simulation tools provide a great assistance for the optimisation of ECT processes. CEA and the Vallourec Research Center have collaborated in order to develop a simulation tool of ECT of tubes. The volume integral method has been chosen for the resolution of Maxwell equations in a stratified medium, in order to get accurate results with a computation time short enough to carry out optimisation or inversion procedures. A fast model has been developed for the simulation of ECT of non magnetic tubes using specific external probes. New flaw geometries have been modelled: holes and notches with flat bottom. Validations of the developments, which have been integrated to the CIVA platform, have been carried out using experimental data recorded in laboratory conditions and in. industrial conditions, successively. The integral equations derived are solved using the Galerkin variant of the method of moments with pulse functions as projection functions. In order to overcome some memory limitations, other projection functions have been considered. A new discretization scheme based on non-uniform B-Splines of degree 1 or 2 has been implemented, which constitutes an original contribution to the existing literature. The decrease of the mesh size needed to get a given accuracy on the result may lead to the simulation of more complex ECT configurations. (author)

  13. An automated eddy current in-service inspection system for nuclear steam generator tubing

    International Nuclear Information System (INIS)

    A prototype steam generator in-service inspection system incorporating remotely-controlled instrumentation linked by a digital transmission line to an instrument and control trailer outside the reactor containment has been designed and manufactured and is presently undergoing field tests. The (Monel 400) steam generator tubes are scanned two at a time using absolute eddy current probes controlled by two remotely-operated probe drives at a scanning speed of 0.5 m/s. The probes are positioned on the tubesheet by a light-weight (1.5 kg) microprocessor-operated tubesheet walker mechanism. Digitized control and data signals are transmitted up to 300 m to the control trailer. There the control and analysis computers extract the relevant signal information and present it in condensed form as labelled graphics on CRT consoles for on-line visual assessment. Hard copy output is also provided for each tube scanned (one per minute). Condensed data is archived on magnetic tapes for additional off-line analysis and comparisons with other inspections

  14. Noise-based tube current reduction method with iterative reconstruction for reduction of radiation exposure in coronary CT angiography

    International Nuclear Information System (INIS)

    Purpose: To investigate the potential of noise-based tube current reduction method with iterative reconstruction to reduce radiation exposure while achieving consistent image quality in coronary CT angiography (CCTA). Materials and methods: 294 patients underwent CCTA on a 64-detector row CT equipped with iterative reconstruction. 102 patients with fixed tube current were assigned to Group 1, which was used to establish noise-based tube current modulation formulas, where tube current was modulated by the noise of test bolus image. 192 patients with noise-based tube current were randomly assigned to Group 2 and Group 3. Filtered back projection was applied for Group 2 and iterative reconstruction for Group 3. Qualitative image quality was assessed with a 5 point score. Image noise, signal intensity, volume CT dose index, and dose-length product were measured. Results: The noise-based tube current modulation formulas were established through regression analysis using image noise measurements in Group 1. Image noise was precisely maintained at the target value of 35.00 HU with small interquartile ranges for Group 2 (34.17–35.08 HU) and Group 3 (34.34–35.03 HU), while it was from 28.41 to 36.49 HU for Group 1. All images in the three groups were acceptable for diagnosis. A relative 14% and 41% reduction in effective dose for Group 2 and Group 3 were observed compared with Group 1. Conclusion: Adequate image quality could be maintained at a desired and consistent noise level with overall 14% dose reduction using noise-based tube current reduction method. The use of iterative reconstruction further achieved approximately 40% reduction in effective dose

  15. CT angiography of the neck: Value of contrast medium dose reduction with low tube voltage and high tube current in a 64–detector row CT

    International Nuclear Information System (INIS)

    Aim: To evaluate the feasibility of a low-dose contrast medium protocol for 64-detector row computed tomography angiography (CTA) of the neck using a low-tube-voltage/high-tube-current setting. Materials and methods: A phantom study was performed using 64-detector row spiral CT at multiple tube voltage and current settings. Iodine contrast medium attenuation curves were acquired by processing and used to select the best contrast medium-to-noise ratio (CNR). A prospective clinical study was then performed on 84 patients requiring neck CTA. Patients were randomly divided into two groups of 42. Group A was examined using the conventional imaging protocol (120 kV, 400 mAs) and group B was examined at 80 kV and 600 mAs along with a 50% reduction in contrast medium dose. The CT dose index-volume (CTDIvol), background noise (BN), and CNR were measured and statistically analysed. Various image quality criteria were evaluated by two senior radiologists using a qualitative five-point scale. Results: Comparing group B with A, CTDIvol decreased by 54% (B: 27.48 mGy, A: 59.11 mGy), however, the CNR increased by 50%. The mean attenuation, which was caused by venous streak artefacts, was significantly lower in group B than A. Qualitative image analysis found that all criteria were significantly better for group B than A. Conclusion: At 64-detector row spiral CT, the low-tube-voltage/high-tube-current with low-dose contrast medium protocol was superior to the conventional protocol regarding radiation dose, venous streak artefacts, and image quality, and is feasible for CTA of the neck

  16. Influence of tube voltage and current on in-line phase contrast imaging using a microfocus x-ray source

    Institute of Scientific and Technical Information of China (English)

    Li Zheng; Yu Ai-Min; Li Cheng-Quan

    2007-01-01

    In-line x-ray phase contrast imaging has attracted much attention due to two major advantages:its effectiveness in imaging weakly absorbing materials,and the simplicity of its facilities.In this paper a comprehensive theory based on Wigner distribution developed by Wu and Liu [Med.Phys.31 2378-2384(2004)] is reviewed.The influence of x-ray source and detector on the image is discussed.Experiments using a microfocus x-ray source and a CCD detector are conducted,which show the role of two key factors on imaging:the tube voltage and tube current.High tube current and moderate tube voltage are suggested for imaging.

  17. Eddy Current Signature Classification of Steam Generator Tube Defects Using A Learning Vector Quantization Neural Network

    International Nuclear Information System (INIS)

    A major cause of failure in nuclear steam generators is degradation of their tubes. Although seven primary defect categories exist, one of the principal causes of tube failure is intergranular attack/stress corrosion cracking (IGA/SCC). This type of defect usually begins on the secondary side surface of the tubes and propagates both inwards and laterally. In many cases this defect is found at or near the tube support plates

  18. Achieving consistent image quality and overall radiation dose reduction for coronary CT angiography with body mass index-dependent tube voltage and tube current selection

    International Nuclear Information System (INIS)

    Aim: To develop a quantitative body mass index (BMI)-dependent tube voltage and tube current selection method for obtaining consistent image quality and overall dose reduction in computed tomography coronary angiography (CTCA). Methods and materials: The images of 190 consecutive patients (group A) who underwent CTCA with fixed protocols (100 kV/193 mAs for 100 patients with a BMI of <27 and 120 kV/175 mAs for 90 patients with a BMI of >27) were retrospectively analysed and reconstructed with an adaptive statistical iterative reconstruction (ASIR) algorithm at 50% blending. Image noise was measured and the relationship to BMI was studied to establish BMI-dependent tube current for obtaining CTCA images with user-specified image noise. One hundred additional cardiac patients (group B) were examined using prospective triggering with the BMI-dependent tube voltage/current. CTCA image-quality score, image noise, and effective dose from groups B and C (subgroup of A of 100 patients examined with prospective triggering only) were obtained and compared. Results: There was a linear relationship between image noise and BMI in group A. Using a BMI-dependent tube current in group B, an average CTCA image noise of 27.7 HU (target 28 HU) and 31.7 HU (target 33 HU) was obtained for the subgroups of patients with BMIs of >27 and of <27, respectively, and was independent of patient BMI. There was no difference between image-quality scores between groups B and C (4.52 versus 4.60, p > 0.05). The average effective dose for group B (2.56 mSv) was 42% lower than group C (4.38 mSv; p < 0.01). Conclusion: BMI-dependent tube voltage/current selection in CTCA provides an individualized protocol that generates consistent image quality and helps to reduce overall patient radiation dose. - Highlights: • BMI-dependent kVp and mA selection method may be established in CCTA. • BMI-dependent kVp and mA enables consistent CCTA image quality. • Overall dose reduction of 40% can

  19. Steam generator and preheater tube ID fouling and the impact on reactor inlet header temperature and eddy current inspections

    International Nuclear Information System (INIS)

    Materials selection is an important consideration in new build and refurbishment of Heavy Water Reactors (HWR). This paper will focus on the impacts of the deposit of magnetite on the tube ID of steam generators and preheater. Bruce Power OPEX is being shared to illustrate the importance of materials selection. The deposit of magnetite on the tube ID of steam generators (SG) and preheater (PH) has two significant impacts that will be presented. Firstly, the degradation in SG and PH thermal performance causes a rise in the reactor inlet header temperature (RIHT). This rising trend continues unabated as long as deposits on the tube ID continues. If not managed this may result in loss of production due to the RIHT limits being reached. Mitigating actions such as tube ID cleaning is only a temporary solution as it does not stop the root cause which is feeder flow accelerated corrosion (FAC). Secondly, deposit of magnetite on the tube ID of steam generators (SG) and preheater (PH) has an impact on tube inspections as required by CSA N285.4. There are two impacts on SG and PH inspections. ID deposits reduces the clearance for eddy current probes in the tubes and make it more difficult to acquire inspection data. Additionally, tube ID deposits can reduce the effectiveness to detect and size flaws in the SG and PH tubes. Both issues make eddy current inspection a challenge for the utilities. These impacts affect the operation and inspection and maintenance of CANDU nuclear power plants at Bruce Power. Where possible these issues should be addressed in any future new build or refurbishment of HWR power plants. (author)

  20. Preliminary research on eddy current bobbin quantitative test for heat exchange tube in nuclear power plant

    Science.gov (United States)

    Qi, Pan; Shao, Wenbin; Liao, Shusheng

    2016-02-01

    For quantitative defects detection research on heat transfer tube in nuclear power plants (NPP), two parts of work are carried out based on the crack as the main research objects. (1) Production optimization of calibration tube. Firstly, ASME, RSEM and homemade crack calibration tubes are applied to quantitatively analyze the defects depth on other designed crack test tubes, and then the judgment with quantitative results under crack calibration tube with more accuracy is given. Base on that, weight analysis of influence factors for crack depth quantitative test such as crack orientation, length, volume and so on can be undertaken, which will optimize manufacture technology of calibration tubes. (2) Quantitative optimization of crack depth. Neural network model with multi-calibration curve adopted to optimize natural crack test depth generated in in-service tubes shows preliminary ability to improve quantitative accuracy.

  1. 换热器管板角焊缝相控阵自动超声检测技术研究%Research on Phased Array Automatically Ultrasonic Testing Technique of Tube to Tube-sheet Welds in Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    郭伟灿; 钱盛杰; 凌张伟

    2015-01-01

    在换热器的制作过程中,换热管与管板常采用焊接形式,焊缝的质量是保证换热器长期正常运行的关键。常规的超声检测方法具有系统复杂、检测效率低等缺点。因此,提出了相控阵超声检测技术,并开发了相控阵超声检测系统,以实现对管板角焊缝的自动超声检测。系统由周向步进电机实现周向扫查,纵向扫查采用相控阵探头电子线扫查,从而实现超声 C 扫描检测。通过带有气孔、未熔合等典型缺陷对检测系统进行试验研究。结果表明,该技术可以有效地检测出换热器管板角焊缝中的典型缺陷。%In the process of produce heat exchangers,heat exchanger′s tube and tube sheet conjunction adopt the form of welding,the quality of welding is the key insurance for the long and normal operation of the heat exchangers.The conventional ultrasonic testing method has many disadvantages like complicated system and low efficiency of detection.Thus,it puts forward the phased array ultrasonic testing technique and develops the ultrasonic testing system to accomplish the automatically ultrasonic testing of the tube to tube-sheet welds.The ultrasonic C-scan was carried out by the ultrasonic testing system with its circumfer-ential scanning by a mechanical scanning device while the axial electronic linear scanning by the phased array probe.At last,the tests on samples with typical flaws such as porosity flaws and the incomplete fu-sion flaws were performed by the ultrasonic testing system.Experiment results showed that the phased ar-ray ultrasonic technique could effectively detect the typical flaws in the tube to tube-sheet welds of heat exchanger.

  2. The impact on CT dose of the variability in tube current modulation technology: a theoretical investigation

    International Nuclear Information System (INIS)

    Body CT scans are routinely performed using tube-current-modulation (TCM) technology. There is notable variability across CT manufacturers in terms of how TCM technology is implemented. Some manufacturers aim to provide uniform image noise across body regions and patient sizes, whereas others aim to provide lower noise for smaller patients. The purpose of this study was to conduct a theoretical investigation to understand how manufacturer-dependent TCM scheme affects organ dose, and to develop a generic approach for assessing organ dose across TCM schemes. The adult reference female extended cardiac-torso (XCAT) phantom was used for this study. A ray-tracing method was developed to calculate the attenuation of the phantom for a given projection angle based on phantom anatomy, CT system geometry, x-ray energy spectrum, and bowtie filter filtration. The tube current (mA) for a given projection angle was then calculated as a log-linear function of the attenuation along that projection. The slope of this function, termed modulation control strength, α, was varied from 0 to 1 to emulate the variability in TCM technology. Using a validated Monte Carlo program, organ dose was simulated for five α values (α = 0, 0.25, 0.5, 0.75, and 1) in the absence and presence of a realistic system mA limit. Organ dose was further normalized by volume-weighted CT dose index (CTDIvol) to obtain conversion factors (h factors) that are relatively independent of system specifics and scan parameters. For both chest and abdomen-pelvis scans and for 24 radiosensitive organs, organ dose conversion factors varied with α, following second-order polynomial equations. This result suggested the need for α-specific organ dose conversion factors (i.e., conversion factors specific to the modulation scheme used). On the other hand, across the full range of α values, organ dose in a TCM scan could be derived from the conversion factors established for a fixed-mA scan (hFIXED). This was possible by

  3. Prospective estimation of organ dose in CT under tube current modulation

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Xiaoyu, E-mail: xt3@duke.edu [Department of Biomedical Engineering, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Li, Xiang [Department of Physics, Cleveland State University, Cleveland, Ohio 44115 (United States); Segars, W. Paul [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Frush, Donald P. [Division of Pediatric Radiology, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Departments of Physics and Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States)

    2015-04-15

    Purpose: Computed tomography (CT) has been widely used worldwide as a tool for medical diagnosis and imaging. However, despite its significant clinical benefits, CT radiation dose at the population level has become a subject of public attention and concern. In this light, optimizing radiation dose has become a core responsibility for the CT community. As a fundamental step to manage and optimize dose, it may be beneficial to have accurate and prospective knowledge about the radiation dose for an individual patient. In this study, the authors developed a framework to prospectively estimate organ dose for chest and abdominopelvic CT exams under tube current modulation (TCM). Methods: The organ dose is mainly dependent on two key factors: patient anatomy and irradiation field. A prediction process was developed to accurately model both factors. To model the anatomical diversity and complexity in the patient population, the authors used a previously developed library of computational phantoms with broad distributions of sizes, ages, and genders. A selected clinical patient, represented by a computational phantom in the study, was optimally matched with another computational phantom in the library to obtain a representation of the patient’s anatomy. To model the irradiation field, a previously validated Monte Carlo program was used to model CT scanner systems. The tube current profiles were modeled using a ray-tracing program as previously reported that theoretically emulated the variability of modulation profiles from major CT machine manufacturers Li et al., [Phys. Med. Biol. 59, 4525–4548 (2014)]. The prediction of organ dose was achieved using the following process: (1) CTDI{sub vol}-normalized-organ dose coefficients (h{sub organ}) for fixed tube current were first estimated as the prediction basis for the computational phantoms; (2) each computation phantom, regarded as a clinical patient, was optimally matched with one computational phantom in the library; (3

  4. Methods of evaluation of accuracy with multiple essential parameters for eddy current measurement of pressure tube to calandria tube gap in CANDU reactors

    International Nuclear Information System (INIS)

    The purpose of inspection qualification of a particular inspection system is to show that it meets applicable inspection specification requirements. Often a requirement of the inspection system is that it meets a particular accuracy. In the case of a system with multiple inputs accompanied by additional influential parameters, calculation of the system's output accuracy can be formidable. Measurement of pressure-tube to calandria tube gap in CANDU reactors using an eddy current based technique is presented as a particular example of a system where multiple essential parameters combine to generate a final uncertainty for the inspection system. This paper outlines two possible methods of calculating such a system's accuracy, and discusses the advantages and disadvantages of each. (author)

  5. Optimization of recommendations for abdomen computerized tomography based on reconstruction filters, voltage and tube current

    International Nuclear Information System (INIS)

    The use of computed tomography has increased significantly over the past decades. In Brazil the use increased more than twofold from 2008 to 2014, in the meantime the abdomen procedures have tripled. The high frequency of this procedure combined by the increasing collective radiation dose in medical exposures, has resulted development tools to maximize the benefit in CT images. This work aimed to establish protocols optimized in abdominal CT through acquisitions parameters and reconstructions techniques based on filters kernels. A sample of patients undergoing abdominal CT in a diagnostic center of Rio de Janeiro was assessed. Had been collected patients information and acquisitions parameters. The phantoms CT image acquisitions were performed by using different voltage values by adjusting the tube current (mAs) to obtain the same value from CTDIvol patients with normal BMI. Afterwards, the CTDIvol values were reduced by 30%, 50% and 60%. All images were reconstructed with low-contrast filters (A) and standard filters (B). The CTDIvol values for patients with normal BMI were 7% higher than in patients with underweight BMI and 30%, 50% and 60% lower than the overweight, obese I and III patients, respectively. The evaluations of image quality showed that variation of the current (mA) and the reconstruction filters did not affect the Hounsfield values. When the contrast-to-noise ratio (CNR) was normalized to CTDIvol, the protocols acquired with 60% reduction of CTDIvol with 140 kV and 80 kV showed CNR 6% lower than the routine. Modifications of the acquisition parameters did not affect spatial resolution, but the post-processing with B filters reduced the spatial frequency by 16%. With reduced the dose of 30%, lesions in the spleen had the CNR higher than 10% routine protocols with 140 kV acquired and post-processed to filter A. The image post-processing with a filter A with a 80kV voltage provided CNR values equal to the routine for the liver lesions with a 30

  6. Convolution-based estimation of organ dose in tube current modulated CT.

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W Paul; Dixon, Robert L; Samei, Ehsan

    2016-05-21

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460-7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18-70 years, weight range: 60-180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ([Formula: see text]) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate [Formula: see text] values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying [Formula: see text] with the organ dose coefficients ([Formula: see text]). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled. The discrepancy between the estimated organ dose and dose simulated using TCM Monte Carlo program was quantified. We further compared the

  7. Convolution-based estimation of organ dose in tube current modulated CT

    Science.gov (United States)

    Tian, Xiaoyu; Segars, W. Paul; Dixon, Robert L.; Samei, Ehsan

    2016-05-01

    Estimating organ dose for clinical patients requires accurate modeling of the patient anatomy and the dose field of the CT exam. The modeling of patient anatomy can be achieved using a library of representative computational phantoms (Samei et al 2014 Pediatr. Radiol. 44 460–7). The modeling of the dose field can be challenging for CT exams performed with a tube current modulation (TCM) technique. The purpose of this work was to effectively model the dose field for TCM exams using a convolution-based method. A framework was further proposed for prospective and retrospective organ dose estimation in clinical practice. The study included 60 adult patients (age range: 18–70 years, weight range: 60–180 kg). Patient-specific computational phantoms were generated based on patient CT image datasets. A previously validated Monte Carlo simulation program was used to model a clinical CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Forchheim, Germany). A practical strategy was developed to achieve real-time organ dose estimation for a given clinical patient. CTDIvol-normalized organ dose coefficients ({{h}\\text{Organ}} ) under constant tube current were estimated and modeled as a function of patient size. Each clinical patient in the library was optimally matched to another computational phantom to obtain a representation of organ location/distribution. The patient organ distribution was convolved with a dose distribution profile to generate {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} values that quantified the regional dose field for each organ. The organ dose was estimated by multiplying {{≤ft(\\text{CTD}{{\\text{I}}\\text{vol}}\\right)}\\text{organ, \\text{convolution}}} with the organ dose coefficients ({{h}\\text{Organ}} ). To validate the accuracy of this dose estimation technique, the organ dose of the original clinical patient was estimated using Monte Carlo program with TCM profiles explicitly modeled

  8. Eddy currents inspection of CANDU steam generator' tubes using Zetec's ZR-1 Robot: experience in Romania

    International Nuclear Information System (INIS)

    'Full text:' The paper introduces the new ZR-1 Robot System for Inspection and Maintenance/Repair from Zetec that combines the newest state-of-the-art robotics technology with Zetec experience-based innovation to address the needs for inspection and repair of steam generators. The multipurpose ZR-1 can be easily installed to perform the necessary eddy current inspection and remain installed ready for follow-up maintenance and repair. It has superior technical performances and a modular three axis motion of arm that enables 100% coverage of tube sheet. Automated, repeatable, and precise positioning of toolheads, ensures accurate delivery and reducing costly rework and reduces inspection time by 30%. The modular, lightweight, and portable design permits easy assembly and disassembly through small openings and it reduces setup/tear down time by 30%. The first deployment of the new ZR-1 Robot was made in September 2004 at the Cernavoda NPP inspection outage. The Cernavoda plant has four Advanced 600 MW CANDU-design generators that have been in service since 1996. The paper presents also the Zetec's filed experience and customer experience with this system. It describes the equipment setup in Cernavoda's generator mock-up, functional testes and calibration. Finally, provides details on the execution of the inspection, options for standardizing the inspection techniques and conclusions. (author)

  9. Automatic Condition Monitoring of Industrial Rolling-Element Bearings Using Motor’s Vibration and Current Analysis

    OpenAIRE

    Zhenyu Yang

    2015-01-01

    An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated by the potential commercialization, the developed system is promoted mainly using off-the-shelf techniques, that is, the high-frequency resonance technique with envelope detection and the average of short-time ...

  10. Development of a multi-channel eddy current examination system for automated inspection of steam generator tubing

    International Nuclear Information System (INIS)

    A segmented absolute 8-coil probe for inspection of heat exchanger tubing has been developed together with the appropriate multi-channel eddy current instrument and evaluation algorithm. The system has been qualified in the laboratory by tests on artificially induced flaws and in field by comparing results obtained on actual flaws with data from ultrasonic wall thickness measurements. (author)

  11. Estimation of breast dose saving potential using a breast positioning technique for organ-based tube current modulated CT

    Science.gov (United States)

    Fu, Wanyi; Tian, Xiaoyu; Sturgeon, Gregory; Agasthya, Greeshma; Segars, William Paul; Goodsitt, Mitchell M.; Kazerooni, Ella A.; Samei, Ehsan

    2016-04-01

    In thoracic CT, organ-based tube current modulation (OTCM) reduces breast dose by lowering the tube current in the 120° anterior dose reduction zone of patients. However, in practice the breasts usually expand to an angle larger than the dose reduction zone. This work aims to simulate a breast positioning technique (BPT) to constrain the breast tissue to within the dose reduction zone for OTCM and to evaluate the corresponding potential reduction in breast dose. Thirteen female anthropomorphic computational phantoms were studied (age range: 27-65 y.o., weight range: 52-105.8 kg). Each phantom was modeled in the supine position with and without application of the BPT. Attenuation-based tube current (ATCM, reference mA) was generated by a ray-tracing program, taking into account the patient attenuation change in the longitudinal and angular plane (CAREDose4D, Siemens Healthcare). OTCM was generated by reducing the mA to 20% between +/- 60° anterior of the patient and increasing the mA in the remaining projections correspondingly (X-CARE, Siemens Healthcare) to maintain the mean tube current. Breast tissue dose was estimated using a validated Monte Carlo program for a commercial scanner (SOMATOM Definition Flash, Siemens Healthcare). Compared to standard tube current modulation, breast dose was significantly reduced using OTCM by 19.8+/-4.7%. With the BPT, breast dose was reduced by an additional 20.4+/-6.5% to 37.1+/-6.9%, using the same CTDIvol. BPT was more effective for phantoms simulating women with larger breasts with the average breast dose reduction of 30.2%, 39.2%, and 49.2% from OTCMBP to ATCM, using the same CTDIvol for phantoms with 0.5, 1.5, and 2.5 kg breasts, respectively. This study shows that a specially designed BPT improves the effectiveness of OTCM.

  12. In service inspection of steam generator tubes with a multifrequence eddy current apparatus

    International Nuclear Information System (INIS)

    The described multifrequency device has been designed and developed for a complete testing of tubes. It is necessary to eliminate the signals given by plates, expanded parts, background noises and magnetic signals which can mask some possible defects

  13. Ambipolar Diffusion in Direct-Current Positive Column with Variations in Radius of Discharge Tube

    Institute of Scientific and Technical Information of China (English)

    D. AKBAR; S. BILIKMEN

    2006-01-01

    @@ The ambipolar diffusion and argon ion mobility as functions of the reduced electric field and pressure times the tube radius are investigated in a weakly ionized non-uniform glow discharge plasma system.

  14. Determination of the field dependence of the intergranular critical current in a YBCO tube by horizontal traversals

    Science.gov (United States)

    Çelebi, S.; LeBlanc, M. A. R.

    2006-12-01

    The magnetic flux density in the cavity of a sintered tube of Yttrium Barium Copper Oxide (YBCO) is measured as a function of H∥, the axial magnetic field impressed and removed after zero field cooling (ZFC). We note that, in a short thick-walled hollow cylinder of a weak-linked polycrystalline high- Tc superconductor, the magnetic field in the cavity of the tube, Hz hole , rises above the applied field H∥ when it is initially increasing. Consequently the standard approach to determine the critical current density from an ascending sweep of H∥ alone, or a descending sweep alone cannot be exploited. However the field dependence of the intergranular critical current density Jcm can be reliably obtained from the horizontal traversals of Hz hole vs H∥. Comparison of the experimental data with model calculations for the horizontal traversals of the hysteresis curves show that the intergranular critical current density in the YBCO tube has a Kim-like field dependence. The magnetization of the grains has a significant influence on the flux density in the cavity of the tube.

  15. Prospective ECG-triggered coronary CT angiography: clinical value of noise-based tube current reduction method with iterative reconstruction.

    Directory of Open Access Journals (Sweden)

    Junlin Shen

    Full Text Available OBJECTIVES: To evaluate the clinical value of noise-based tube current reduction method with iterative reconstruction for obtaining consistent image quality with dose optimization in prospective electrocardiogram (ECG-triggered coronary CT angiography (CCTA. MATERIALS AND METHODS: We performed a prospective randomized study evaluating 338 patients undergoing CCTA with prospective ECG-triggering. Patients were randomly assigned to fixed tube current with filtered back projection (Group 1, n = 113, noise-based tube current with filtered back projection (Group 2, n = 109 or with iterative reconstruction (Group 3, n = 116. Tube voltage was fixed at 120 kV. Qualitative image quality was rated on a 5-point scale (1 = impaired, to 5 = excellent, with 3-5 defined as diagnostic. Image noise and signal intensity were measured; signal-to-noise ratio was calculated; radiation dose parameters were recorded. Statistical analyses included one-way analysis of variance, chi-square test, Kruskal-Wallis test and multivariable linear regression. RESULTS: Image noise was maintained at the target value of 35HU with small interquartile range for Group 2 (35.00-35.03HU and Group 3 (34.99-35.02HU, while from 28.73 to 37.87HU for Group 1. All images in the three groups were acceptable for diagnosis. A relative 20% and 51% reduction in effective dose for Group 2 (2.9 mSv and Group 3 (1.8 mSv were achieved compared with Group 1 (3.7 mSv. After adjustment for scan characteristics, iterative reconstruction was associated with 26% reduction in effective dose. CONCLUSION: Noise-based tube current reduction method with iterative reconstruction maintains image noise precisely at the desired level and achieves consistent image quality. Meanwhile, effective dose can be reduced by more than 50%.

  16. Inspection performance of eddy current probe for in-service inspection of HTTR intermediate heat exchanger tubes

    International Nuclear Information System (INIS)

    An experimental study was carried out to clarify the inspection performance of an eddy current probe for the inservice inspection of the intermediate heat exchanger (IHX) tubes of the high-temperature engineering test reactor. Test tubes were made of the same material (Hastelloy XR) and dimensions as those of the IHX, and had artificial discontinuities with reference to the standards of steam generator tubes in ASME Boiler and Pressure Vessel Code which were conservative for the IHX tubes. It was confirmed that the inspection performance of the probe satisfied the ASME standards in the base metal. The probe also could detect discontinuities such as a 90deg circumferential groove with 0.5 mm in width and 20% through from the outer tube surface, and a 100% through-wall hole with 0.5 mm in diameter. The inspection performance was lowered for discontinuities in the welded joint, and flat bottom holes with 1.7 mm in diameter were not detected. The inspection limit of 90deg circumferential grooves with 1.5 mm in width, was above 60% in depth for outer surface and 20% in depth for inner surface in the welded joint. (author)

  17. Eddy Currents Inspection of CANDU Steam Generator Tubes using Zetec's ZR-1 Robot. Experience in Romania

    International Nuclear Information System (INIS)

    Full text of publication follows: The commercial operation of Unit 1 of Cernavoda NPP started on 2 December, 1996. The unit's reactor type is PHWR-CANDU 6 (electrical capacity 706 MWe), using natural uranium. The nuclear fuel is manufactured in Romania. The Cernavoda nuclear power plant has four CANDU - design steam generators that have been in service since 1996. The paper introduces the new ZR-1 Robot System for Inspection and Maintenance/Repair from Zetec that combines the newest state-of-the-art robotics technology with Zetec experience - based innovation to address the needs for inspection and repair of steam generators. The multipurpose ZR-1 can be easily installed to perform the necessary eddy current inspection and remain installed ready for follow-up maintenance and repair. It has superior technical performances and a modular three axis motion of arm that enables 100% coverage of tube sheet. Automated, repeatable, and precise positioning of tool heads ensures accurate delivery and reducing costly rework and reduces inspection time by 30%. The modular, light weight, and portable design permits easy assembly and disassembly through small openings and it reduces setup/tear down time by 30%. The first deployment of the new ZR-1 Robot was made in September 2004 at the Cernavoda NPP inspection outage. The unit's reactor type is PHWR-CANDU 6 (electrical capacity 706 MWe), using natural uranium; the nuclear fuel is manufactured in Romania. The Cernavoda nuclear power plant Unit 1 has four CANDU - design steam generators that have been in service since 1996. The paper presents also the Zetec's field experience and customer experience with this system. It describes the equipment setup in Cernavoda's steam generators mock-up, functional tests and calibration. Finally, provides details on the execution of the inspection, options for standardizing the inspection techniques and conclusions. (authors)

  18. Condensation experiments for counter-current flow limitation at lower end of an inverted U-tube

    International Nuclear Information System (INIS)

    Counter-current flow limitation (CCFL) characteristics at the lower end of an inverted U-tube (18.4 mm diameter and 1.0 m length of straight-part) simulating steam generator (SG) U-tubes were measured under the conditions of steam condensation at atmospheric pressure and were compared with those measured in air-water experiments to evaluate effects of condensation. Steam was supplied to the inverted U-tube at a constant volume flow rate QG, the volume flow rate QL of water flowing into the lower tank was measured, and the relationship between QG and QL were expressed in terms of the Wallis parameters. Pressure drops ΔP between the top of the inverted U-tube and the lower tank were also measured, and flow patterns were estimated by comparing the fluctuation of ΔP with that in air-water experiments. As a result, the flow patterns under CCFL conditions were classified into three types, CCFL-P, CCFL-L and CCFL-T, in which CCFL took place inside the pipe, at the lower end and either in the pipes or at the lower end, respectively. In the cases of CCFL-P and CCFL-L, CCFL characteristics in the inverted U-tube agreed well with those in the air-water experiments. This implies that the CCFL correlation derived from the air-water experiments could be applied to the inverted U-tube under the conditions of steam condensation. (author)

  19. Study of methods for testing the tubes of steam generators by means of Eddy Current

    International Nuclear Information System (INIS)

    Comparative studies of equipment have been performed at Ringhals. Automatic testing systems, type Vincotte have been found to be flexible. Multi-frequency systems are to be preferred. The limits of detection of defects can be estimated in three classes including defects which are impossible to detect. Real defects in Ringhals-2 and Ringhals-3 were used as reference. (G.B.)

  20. Assessment of thermo-electric techniques for scrape-off layer current drive in flux-tube geometry

    International Nuclear Information System (INIS)

    The magnitude of the parallel current that can be driven by asymmetries between divertor target plates is calculated in magnetic flux-tube geometry. Current can be driven between ends of the flux-tube by passive techniques that generate a thermo-electric potential by heating or cooling one side relative to the other through pumping or neutral gas injection. The induced thermo-electric potential depends on the total particle flux pumped relative to the total recycling flux. For the geometry considered, pumping efficiency is higher for pumping by the target plate or from the private flux zone than for pumping from the outer side of the plate. Neutral gas injection is not as effective at generating an asymmetry. An important constraint for these methods may be the additional heat flux delivered to the hotter target, but additional Ohmic heating is much smaller than that generated by electrical biasing.

  1. Application of wavelet analysis to signal processing for Eddy--Current Testing of FBR steam generator tubes

    International Nuclear Information System (INIS)

    We have been studying an advanced signal processing method for ECT (Eddy-Current Testing) to detect flaws in heat exchanger tubes of steam generators in a FBR (Fast Breeder Reactor) plant. The data obtained from the testing of these steam generator tubes showed some noise characteristics different from ones in light water reactor plants. Thus, an improvement of the signal-to-noise ratio of the processed ECT data is desired in order to increase reliability of the inspection. We have evaluated the signal-to-noise ratio as a performance measure using the actual plant data by means of wavelet analysis technique, which has been applied successfully in many fields to detect anomalous signals. First, we synthesized an ECT data containing flaws by combining the noisy signals from an in-field inspection of one heat exchanger tube with separately measured flaw signals from a calibration piece that had various machined flaws. Next, we evaluated the performance of the wavelet analysis technique by comparing it with a reference Fourier method. The performance of this technique is much better than by conventional analysis. For example, the signal-to-noise ratio of the discrete wavelet analysis method is 1.4 times greater than that by a conventional, low-pass filter method. Thus, we have shown that wavelet analysis has advantages over conventional method of detecting flaws in FBR steam generator tubes because of its sensitivity to localized events, such as sudden signal changes. (author)

  2. The effects of surface tension on flooding in counter-current two-phase flow in an inclined tube

    Energy Technology Data Exchange (ETDEWEB)

    Deendarlianto [Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No.2 Yogyakarta 55281 (Indonesia); Forschungszentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Ousaka, Akiharu [Department of Mechanical Engineering, The University of Tokushima, 2-1 Minami Josanjima, Tokushima 770-8506 (Japan); Indarto [Department of Mechanical and Industrial Engineering, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No.2 Yogyakarta 55281 (Indonesia); Kariyasaki, Akira [Department of Chemical Engineering, Fukuoka University, 8-19-1, Jyonan-ku, Fukuoka 814-0180 (Japan); Lucas, Dirk; Vallee, Christophe [Forschungszentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden (Germany); Vierow, Karen; Hogan, Kevin [Department of Nuclear Engineering Texas A and M University, 129 Zachry Engineering Center, 3133 TAMU College Station, TX 77843-3133 (United States)

    2010-10-15

    The purpose of the present study is to investigate the effects of surface tension on flooding phenomena in counter-current two-phase flow in an inclined tube. Previous studies by other researchers have shown that surface tension has a stabilizing effect on the falling liquid film under certain conditions and a destabilizing or unclear trend under other conditions. Experimental results are reported herein for air-water systems in which a surfactant has been added to vary the liquid surface tension without altering other liquid properties. The flooding section is a tube of 16 mm in inner diameter and 1.1 m length, inclined at 30-60 from horizontal. The flooding mechanisms were observed by using two high-speed video cameras and by measuring the time variation of liquid hold-up along the test tube. The results show that effects of surface tension are significant. The gas velocity needed to induce flooding is lower for a lower surface tension. There was no upward motion of the air-water interfacial waves upon flooding occurrence, even for lower a surface tension. Observations on the liquid film behavior after flooding occurred suggest that the entrainment of liquid droplets plays an important role in the upward transport of liquid. Finally, an empirical correlation for flooding velocities is proposed that includes functional dependencies on surface tension and tube inclination. (author)

  3. SU-E-I-37: Eye Lens Dose Reduction From CT Scan Using Organ Based Tube Current Modulation

    International Nuclear Information System (INIS)

    Purpose: To investigate the eye lens dose reduction by CT scan with organ based tube current modulation (OBTCM) using GPU Monte Carlo code ARCHER-CT. Methods: 36 X-ray sources and bowtie filters were placed around the patient head with the projection angle interval of 10° for one rotation of CT scan, each projection was simulated respectively. The voxel eye models with high resolution(0.1mm*0.1mm*0.1mm) were used in the simulation and different tube voltage including 80kVp, 100kVp, 120kVp and 140kVp were taken into consideration. Results: The radiation doses to the eye lens increased with the tube voltage raised from 80kVp to 140kVp, and the dose results from 0° (AP) direction are much higher than those from 180° (PA) direction for all the 4 different tube voltage investigated. This 360° projection dose characteristic enables organ based TCM, which can reduce the eye lens dose by more than 55%. Conclusion: As the eye lens belongs to superficial tissues, its radiation dose to external exposure like CT is direction sensitive, and this characteristic feature makes organ based TCM to be an effective way to reduce the eye lens dose, so more clinical use of this technique were recommended. National Nature Science Foundation of China(No.11475047)

  4. Effects of automatic tube potential selection on radiation dose index, image quality, and lesion detectability in pediatric abdominopelvic CT and CTA: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Brinkley, Michael F.; Choudhury, Kingshuk Roy; Frush, Donald P. [Duke University School of Medicine, Department of Radiology, DUMC Box 3808, Durham, NC (United States); Ramirez-Giraldo, Juan C. [Siemens Healthcare, Malvern (United States); Samei, Ehsan; Wilson, Joshua M.; Christianson, Olav I. [Duke University School of Medicine, Clinical Imaging Physics Group, Department of Radiology, Durham, NC (United States); Frush, Daniel J. [Duke University School of Medicine, Medical Physics, Durham, NC (United States)

    2016-01-15

    To assess the effect of automatic tube potential selection (ATPS) on radiation dose, image quality, and lesion detectability in paediatric abdominopelvic CT and CT angiography (CTA). A paediatric modular phantom with contrast inserts was examined with routine pitch (1.4) and high pitch (3.0) using a standard abdominopelvic protocol with fixed 120 kVp, and ATPS with variable kVp in non-contrast, contrast-enhanced, and CTA mode. The volume CT dose index (CTDI{sub vol}), contrast-to-noise ratio (CNR) and lesion detectability index (d') were compared between the standard protocol and ATPS examinations. CTDI{sub vol} was reduced in all routine pitch ATPS examinations, with dose reductions of 27-52 % in CTA mode (P < 0.0001), 15-33 % in contrast-enhanced mode (P = 0.0003) and 8-14 % in non-contrast mode (P = 0.03). Iodine and soft tissue insert CNR and d' were improved or maintained in all ATPS examinations. kVp and dose were reduced in 25 % of high pitch ATPS examinations and in none of the full phantom examinations obtained after a single full phantom localizer. ATPS reduces radiation dose while maintaining image quality and lesion detectability in routine pitch paediatric abdominopelvic CT and CTA, but technical factors such as pitch and imaging range must be considered to optimize ATPS benefits. (orig.)

  5. Effects of automatic tube potential selection on radiation dose index, image quality, and lesion detectability in pediatric abdominopelvic CT and CTA: a phantom study

    International Nuclear Information System (INIS)

    To assess the effect of automatic tube potential selection (ATPS) on radiation dose, image quality, and lesion detectability in paediatric abdominopelvic CT and CT angiography (CTA). A paediatric modular phantom with contrast inserts was examined with routine pitch (1.4) and high pitch (3.0) using a standard abdominopelvic protocol with fixed 120 kVp, and ATPS with variable kVp in non-contrast, contrast-enhanced, and CTA mode. The volume CT dose index (CTDIvol), contrast-to-noise ratio (CNR) and lesion detectability index (d') were compared between the standard protocol and ATPS examinations. CTDIvol was reduced in all routine pitch ATPS examinations, with dose reductions of 27-52 % in CTA mode (P < 0.0001), 15-33 % in contrast-enhanced mode (P = 0.0003) and 8-14 % in non-contrast mode (P = 0.03). Iodine and soft tissue insert CNR and d' were improved or maintained in all ATPS examinations. kVp and dose were reduced in 25 % of high pitch ATPS examinations and in none of the full phantom examinations obtained after a single full phantom localizer. ATPS reduces radiation dose while maintaining image quality and lesion detectability in routine pitch paediatric abdominopelvic CT and CTA, but technical factors such as pitch and imaging range must be considered to optimize ATPS benefits. (orig.)

  6. CT tube current for attenuation map in a combined PET/CT system. Obese patient simulated phantom study

    International Nuclear Information System (INIS)

    The CT portion of positron emission tomography (PET)/CT provides attenuation correction of the PET emission scan. This study was performed to evaluate how much the CT tube current can be lowered while still providing attenuation maps on PET images. Two body phantoms (outside diameters of 300 and 500 mm) were used to investigate, and PET/CT acquisitions were performed with an Aquiduo PCA-7000B (Toshiba Medical Systems, Otawara, Japan). The CT scan was performed with the following parameters (120 kVp; 0.5-s rotation; 10, 20, 40, 80, 160, 200, 320, 460 mA). After the CT scan, PET images for 18F-fluorodeoxyglucose (18F-FDG) (5.3 kBq/mL) were obtained for 4 min/bed position. The linear attenuation coefficients for 18F-FDG in 300- and 500-mm phantoms, pixel values and SD of CT images, radioactivity concentration values and hot- and cold-sphere contrast on PET images in the 500-mm phantom were evaluated. In the 300-mm phantom, all eight tube currents gave average linear attenuation coefficients of approximately 0.095 cm-1. In contrast, the average linear attenuation coefficients of the 500-mm phantom at 10, 20, and 40 mA were significantly decreased (0.081, 0.087, and 0.092 cm-1, respectively; p-1 of the other tube currents. Further, CT pixel values decreased 10 and 20 mA. Thus, the background radioactivity concentration values at 10 and 20 mA were substantially underestimated to be 57 and 80%, respectively (p<0.05); the hot-sphere contrast values at 10 and 20 mA were 0.26 and 0.29; the cold-sphere contrast values at 10, 20, and 40 mA were -0.33, -0.16, and 0.08. Although the linear attenuation coefficients in the 300-mm phantom remained the same with varying CT tube currents, the 500-mm phantom yielded significant differences in the range 10-40 mA. Therefore, the CT tube currents for attenuation correction should be adjusted over 40 mA in obese patients. (author)

  7. Evaluating current automatic de-identification methods with Veteran’s health administration clinical documents

    Directory of Open Access Journals (Sweden)

    Ferrández Oscar

    2012-07-01

    Full Text Available Abstract Background The increased use and adoption of Electronic Health Records (EHR causes a tremendous growth in digital information useful for clinicians, researchers and many other operational purposes. However, this information is rich in Protected Health Information (PHI, which severely restricts its access and possible uses. A number of investigators have developed methods for automatically de-identifying EHR documents by removing PHI, as specified in the Health Insurance Portability and Accountability Act “Safe Harbor” method. This study focuses on the evaluation of existing automated text de-identification methods and tools, as applied to Veterans Health Administration (VHA clinical documents, to assess which methods perform better with each category of PHI found in our clinical notes; and when new methods are needed to improve performance. Methods We installed and evaluated five text de-identification systems “out-of-the-box” using a corpus of VHA clinical documents. The systems based on machine learning methods were trained with the 2006 i2b2 de-identification corpora and evaluated with our VHA corpus, and also evaluated with a ten-fold cross-validation experiment using our VHA corpus. We counted exact, partial, and fully contained matches with reference annotations, considering each PHI type separately, or only one unique ‘PHI’ category. Performance of the systems was assessed using recall (equivalent to sensitivity and precision (equivalent to positive predictive value metrics, as well as the F2-measure. Results Overall, systems based on rules and pattern matching achieved better recall, and precision was always better with systems based on machine learning approaches. The highest “out-of-the-box” F2-measure was 67% for partial matches; the best precision and recall were 95% and 78%, respectively. Finally, the ten-fold cross validation experiment allowed for an increase of the F2-measure to 79% with partial matches

  8. Wavelets transforms and fuzzy logic in the eddy-current inspection of nuclear power plants steam generator tubes

    International Nuclear Information System (INIS)

    Nuclear power plants steam generators around the world have presented early damage history in their tubes, caused either by design errors or by inappropriate operation, which besides reducing the availability and the safety of the nuclear power plants it also generates heavy economical burden. To monitor the steam generators operational condition, the Eddy Current testing of their tubes is the non destructive method used to detect, localize, classify and to size the defects. The inspection is performed by inserting probes with coils in the tubes generating a signal correlated to the defect. These signals produced by the probe electric circuit are composed by the resistance and the inductive components which can be combined to produce a Lissajous figure in the complex plane. However, Eddy-Current signals contain noise which induce subjectivity inducing to errors in the inspector diagnosis. It is not uncommon to have different diagnosis from two inspectors about the same signal. The present work has the objective of supplying a methodology to analyze the signals which could help the inspector in the difficult task of interpreting the Eddy Current signals. It is proposed a method to remove the noise based on Wavelets Transforms. It is also proposed a normalization in the signal phase angle measurements. Furthermore, two additional characteristics are also studied, namely: the signal amplitudes and the widths of the Lissajous petals. The use of a Fuzzy Logic based inference engine is also developed and its use is demonstrated to be viable. The defects studied in this work are those which produces volumetric changes in the material. In order to test the proposed methodology, several artificial defects were produced in tubes using different types of materials like: brass, 316L stainless steel and Inconel 600 to produce a experimental data base. An Eddy-Current inspection equipment, the MIZ-17ET was used. Around 1000 time series signals of defects were acquired through

  9. The physics of vacuum tubes - principles, technology and current developments; Physique des tubes hyperfrequences, point de situation sur les principes, la technologie et leur evolution

    Energy Technology Data Exchange (ETDEWEB)

    Durand, A.J. [Thales Electron Devices, 78 - Velizy (France)

    2001-04-01

    Microwave vacuum tubes make use of the interaction between an electron beam and an electromagnetic wave in order to generate power at microwave frequencies. The vacuum tubes may be classified in terms of electron beam type (O and M), and whether the standing wave or propagating wave is employed. The performance of this type of vacuum tube is limited both by design considerations and the materials employed in its construction. (authors)

  10. Investigation of eddy current examination on OD fatigue crack for steam generator tubes

    Science.gov (United States)

    Kong, Yuying; Ding, Boyuan; Li, Ming; Liu, Jinhong; Chen, Huaidong; Meyendorf, Norbert G.

    2015-03-01

    The opening width of fatigue crack was very small, and conventional Bobbin probe was very difficult to detect it in steam generator tubes. Different sizes of 8 fatigue cracks were inspected using bobbin probe rotating probe. The analysis results showed that, bobbin probe was not sensitive for fatigue crack even for small through wall crack mixed with denting signal. On the other hand, the rotating probe was easily to detect all cracks. Finally, the OD phase to depth curve for fatigue crack using rotating probe was established and the results agreed very well with the true crack size.

  11. Nondestructive inspection of the tubes of TRIGA IPR-R1 reactor heat exchanger by eddy current testing

    Energy Technology Data Exchange (ETDEWEB)

    Silva Junior, Silverio F.; Silva, Roger F.; Oliveira, Paulo F., E-mail: silvasf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Barreto, Erika S.; Ribeiro, Isabela G.; Fraiz, Felipe C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The IPR-R1 TRIGA MARK 1 reactor is an open pool type reactor, cooled light water. It is used for research activities, personnel training and radioisotopes production, in operation since 1960 at the Nuclear Technology Development Center - CDTN/CNEN. It operates at a maximum thermal power of 100 kW and usually, the fuel cooling is done by natural circulation. If necessary, an external auxiliary cooling system, with a shell-and-tube type heat exchanger, can be used to improve the water heat removal. As part of the ageing management program of the reactor, a nondestructive evaluation of their heat exchanger stainless steel tubes will be performed, in order to verify its integrity. The examinations will be performed using the eddy current test method, which allows the detection and characterization of structural discontinuities in the wall of the tubes, if existing. For this purpose, probes and reference standards were designed and manufactured at CDTN facilities and test procedures were established and validated. In this paper, a description of the proposed infrastructure as well as the test methodology to be used in the examinations are presented and discussed. (author)

  12. Numerical simulations of a multi-frequency eddy current algorithm for improved defect defection in magnetic SG tubes covered by sodium in FBRs

    International Nuclear Information System (INIS)

    In the present paper it is estimated the feasibility of using a multi-frequency algorithm to suppress eddy current signal from sodium bands deposits outside of magnetic steam generator tubes in fast breeder reactors. The ECT signal from outer defects in SG tubes is modeled using a finite element code. The paper presents a detailed analysis of revealing defects under sodium bands using a tuned multi-frequency eddy current algorithm. (author)

  13. Prospective electrocardiogram gated coronary 320-row area detector computed tomography angiography using low tube current scanning with full reconstruction

    International Nuclear Information System (INIS)

    It is possible to obtain equivalent image quality and a lower radiation dose using low tube current scanning with full reconstruction as compared to usual tube current scanning with half reconstruction in a 320-row area detector computed tomography (ADCT) angiography. Of 589 patient underwent coronary CT angiography (CCTA), 11 patients with (RR-PQ) ≥1069 ms were enrolled. In those patients, low tube current (50% mA) scanning with full or half reconstruction were performed. As a control, 11 patients with matched pairs of tube voltage, BMI and heart rate who underwent usual scanning with half reconstruction (100% mA with half reconstruction) were selected. Standard deviation of the CT value (SD) was measured in aorta (Ao), left atrium (LA) and left ventricle (LV), and extended dose-length products (DLP.e) were calculated. Significant motion artifact was not observed in any patients. SD of 50% mA with half reconstruction, 50% mA with full reconstruction, and 100% mA with half reconstruction were 28.1±2.6, 20.3±1.9, 20.7±2.5 Hounsfield unit (HU) in Ao, 34.4±4.4, 24.9±2.8, 24.9±3.1 HU in LA, and 29.7±2.3, 21.7±1.9, 22.1±2.3 HU in LV, respectively. There were not significant differences between 50% mA with full reconstruction and 100% mA with half reconstruction, but there were significant differences between 50% mA with half reconstruction and 50% mA with full reconstruction in all sites. The DLP.e of 50% mA scanning (74.1±21.8 mGy·cm) was significantly lower than 100% mA scanning (161.9±28.9 mGy·cm). CCTA with lower radiation dose and equivalent image quality can be obtained by ADCT using 50% mA scanning with full reconstruction in patients with (RR-PQ) ≥1069 ms. (author)

  14. Overbeaming and overlapping of volume-scan CT with tube current modulation in a 320-detector row CT scanner

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the performance of volume scan tube current modulation (VS-ATCM) with adaptive iterative dose reduction 3D (AIDR3D) technique in abdomen CT examinations. We scanned an elliptical cone-shaped phantom utilizing AIDR3D technique combined with VS-ATCM mode in a 320-detector row CT scanner. The image noise distributions with conventional filtered back-projction (FBP) technique and those with AIDR3D technique were compared. The radiation dose profile and tube current time product (mAs) in three noise levels of VS-ATCM modes were compared. The radiation beam profiles of five preset scan lengths were measured using Gafchromic film strips to assess the effects of overbeaming and everlapping. The results indicated that the image noises with AIDR3D technique was 13–74% lower than those in FBP technique. The mAs distributions can be a prediction for various abdominal sizes when undergoing a VS-ATCM mode scan. Patients can receive the radiation dose of overbeaming and overlapping during the VS-ATCM mode scans. - Highlights: • Noise reduction with AIDR3D in VS-ATCM is 13–74%. • We provide mAs prediction in VS-ATCM for all sizes. • We observe the effect of overbeaming and overlapping

  15. Contribution to perfecting eddy current testing of steam generator tubes of sodium cooled breeders: description of the Monacault loop for the study of sodium deposit influence

    International Nuclear Information System (INIS)

    In the event of sodium-water reaction in the steam generator of a sodium cooled breeder reactor, it is essential to be able to monitor the local loss of thickness of the tubes located in the reaction area. A method for monitoring the tubes by an eddy current probe is being developed for Super Phenix. The sodium deposits on the outer wall of the tubes, as well as their prolonged contact with high temperature sodium are likely to bring about a change in the signals picked up. A test loop, Monacault, has been built in order to clarify the importance of these parameters (effect of sodium deposits, reproducibility of the wetting at different temperatures). It includes three test cells containing the sample tubes having a total of 61 standard defects to be tested. The first results on the wetting of tubes are given and discussed

  16. Transport currents in Bi-2223/Ag tapes made using the tape-in-rectangular tube process, current distribution and Ic stress degradation

    Science.gov (United States)

    Kovác, P.; Husek, I.; Melisek, T.; Metz, A.; van Eck, H. J. N.; ten Haken, B.

    2002-04-01

    Using the tape-in-rectangular tube (TIRT) process, we have made multi-core Bi-2223/Ag tapes with various numbers of filaments (10-162), and with different filament architectures and orientations. We have measured the angular dependence of the transport current of the tape samples with 'parallel' and 'perpendicular' filaments. The transversal Ic distribution obtained by spatially resolved transport measurements ('magnetic knife') illustrates that the filament quality of the TIRT tapes is better at the tape edges than in the centre. The tapes were stressed by two types of tensioning set-up (a short straight sample and a U-shaped spring) and by bending at 77 K. The Ic degradation shows different behaviour for parallel and perpendicular filaments, which is attributed to the difference in filament density and crack propagation.

  17. Transport currents in Bi-2223/Ag tapes made using the tape-in-rectangular tube process, current distribution and Ic stress degradation

    International Nuclear Information System (INIS)

    Using the tape-in-rectangular tube (TIRT) process, we have made multi-core Bi-2223/Ag tapes with various numbers of filaments (10-162), and with different filament architectures and orientations. We have measured the angular dependence of the transport current of the tape samples with 'parallel' and 'perpendicular' filaments. The transversal Ic distribution obtained by spatially resolved transport measurements ('magnetic knife') illustrates that the filament quality of the TIRT tapes is better at the tape edges than in the centre. The tapes were stressed by two types of tensioning set-up (a short straight sample and a U-shaped spring) and by bending at 77 K. The Ic degradation shows different behaviour for parallel and perpendicular filaments, which is attributed to the difference in filament density and crack propagation. (author)

  18. High critical current density in powder-in-tube processed MgB2/Ta/Cu wire

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The magnetization of dense MgB2/Ta/Cu wires prepared by the powder-in-tube method is measured by a SQUID magnetometer. The results indicate that the critical temperature of MgB2/Ta/Cu is around 38.4 K with a sharp transition width of 0.6 K. The MgB2/Ta/Cu wire shows a strong flux pinning and the critical current density is higher than 105 A/cm2 (5 K, self-field) and 104 A/cm2 (20 K, 1 T). Also, the irreversibility field of the sample reaches 6.6 T at 5 K.

  19. Attenuation-based size metric for estimating organ dose to patients undergoing tube current modulated CT exams

    International Nuclear Information System (INIS)

    Purpose: Task Group 204 introduced effective diameter (ED) as the patient size metric used to correlate size-specific-dose-estimates. However, this size metric fails to account for patient attenuation properties and has been suggested to be replaced by an attenuation-based size metric, water equivalent diameter (DW). The purpose of this study is to investigate different size metrics, effective diameter, and water equivalent diameter, in combination with regional descriptions of scanner output to establish the most appropriate size metric to be used as a predictor for organ dose in tube current modulated CT exams. Methods: 101 thoracic and 82 abdomen/pelvis scans from clinically indicated CT exams were collected retrospectively from a multidetector row CT (Sensation 64, Siemens Healthcare) with Institutional Review Board approval to generate voxelized patient models. Fully irradiated organs (lung and breasts in thoracic scans and liver, kidneys, and spleen in abdominal scans) were segmented and used as tally regions in Monte Carlo simulations for reporting organ dose. Along with image data, raw projection data were collected to obtain tube current information for simulating tube current modulation scans using Monte Carlo methods. Additionally, previously described patient size metrics [ED, DW, and approximated water equivalent diameter (DWa)] were calculated for each patient and reported in three different ways: a single value averaged over the entire scan, a single value averaged over the region of interest, and a single value from a location in the middle of the scan volume. Organ doses were normalized by an appropriate mAs weighted CTDIvol to reflect regional variation of tube current. Linear regression analysis was used to evaluate the correlations between normalized organ doses and each size metric. Results: For the abdominal organs, the correlations between normalized organ dose and size metric were overall slightly higher for all three differently (global

  20. Attenuation-based size metric for estimating organ dose to patients undergoing tube current modulated CT exams

    Energy Technology Data Exchange (ETDEWEB)

    Bostani, Maryam, E-mail: mbostani@mednet.ucla.edu; McMillan, Kyle; Lu, Peiyun; Kim, Hyun J.; Cagnon, Chris H.; McNitt-Gray, Michael F. [Departments of Biomedical Physics and Radiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90024 (United States); DeMarco, John J. [Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, California 90095 (United States)

    2015-02-15

    Purpose: Task Group 204 introduced effective diameter (ED) as the patient size metric used to correlate size-specific-dose-estimates. However, this size metric fails to account for patient attenuation properties and has been suggested to be replaced by an attenuation-based size metric, water equivalent diameter (D{sub W}). The purpose of this study is to investigate different size metrics, effective diameter, and water equivalent diameter, in combination with regional descriptions of scanner output to establish the most appropriate size metric to be used as a predictor for organ dose in tube current modulated CT exams. Methods: 101 thoracic and 82 abdomen/pelvis scans from clinically indicated CT exams were collected retrospectively from a multidetector row CT (Sensation 64, Siemens Healthcare) with Institutional Review Board approval to generate voxelized patient models. Fully irradiated organs (lung and breasts in thoracic scans and liver, kidneys, and spleen in abdominal scans) were segmented and used as tally regions in Monte Carlo simulations for reporting organ dose. Along with image data, raw projection data were collected to obtain tube current information for simulating tube current modulation scans using Monte Carlo methods. Additionally, previously described patient size metrics [ED, D{sub W}, and approximated water equivalent diameter (D{sub Wa})] were calculated for each patient and reported in three different ways: a single value averaged over the entire scan, a single value averaged over the region of interest, and a single value from a location in the middle of the scan volume. Organ doses were normalized by an appropriate mAs weighted CTDI{sub vol} to reflect regional variation of tube current. Linear regression analysis was used to evaluate the correlations between normalized organ doses and each size metric. Results: For the abdominal organs, the correlations between normalized organ dose and size metric were overall slightly higher for all three

  1. Fetal doses to pregnant patients from CT with tube current modulation calculated using Monte Carlo simulations and realistic phantoms

    International Nuclear Information System (INIS)

    To investigate the radiation dose to the fetus using retrospective tube current modulation (TCM) data selected from archived clinical records. This paper describes the calculation of fetal doses using retrospective TCM data and Monte Carlo (MC) simulations. Three TCM schemes were adopted for use with three pregnant patient phantoms. MC simulations were used to model CT scanners, TCM schemes and pregnant patients. Comparisons between organ doses from TCM schemes and those from non-TCM schemes show that these three TCM schemes reduced fetal doses by 14, 18 and 25 %, respectively. These organ doses were also compared with those from ImPACT calculation. It is found that the difference between the calculated fetal dose and the ImPACT reported dose is as high as 46 %. This work demonstrates methods to study organ doses from various TCM protocols and potential ways to improve the accuracy of CT dose calculation for pregnant patients. (authors)

  2. EddyOne automated analysis of PWR/WWER steam generator tubes eddy current data

    International Nuclear Information System (INIS)

    INETEC Institute for Nuclear Technology developed software package called Eddy One which has option of automated analysis of bobbin coil eddy current data. During its development and on site use, many valuable lessons were learned which are described in this article. In accordance with previous, the following topics are covered: General requirements for automated analysis of bobbin coil eddy current data; Main approaches to automated analysis; Multi rule algorithms for data screening; Landmark detection algorithms as prerequisite for automated analysis (threshold algorithms and algorithms based on neural network principles); Field experience with Eddy One software; Development directions (use of artificial intelligence with self learning abilities for indication detection and sizing); Automated analysis software qualification; Conclusions. Special emphasis is given on results obtained on different types of steam generators, condensers and heat exchangers. Such results are then compared with results obtained by other automated software vendors giving clear advantage to INETEC approach. It has to be pointed out that INETEC field experience was collected also on WWER steam generators what is for now unique experience.(author)

  3. Al current collector surface treatment and carbon nano tubes influences on Carbon / Carbon super-capacitors performances

    Energy Technology Data Exchange (ETDEWEB)

    Portet, C.; Taberna, P.L.; Simon, P. [Universite Paul Sabatier, CIRIMAT-LCMIE, 31 - Toulouse (France)

    2004-07-01

    Performances of 4 cm{sup 2} carbon/carbon super-capacitors cells using Al current collectors foils in organic electrolyte are presented; the improvement of electrode material has been investigated. In a first part, a surface treatment of the Al current collector is proposed in order to improve contact surface between the current collector and the active material leading to an internal resistance decrease. The process consists in an etching of the Al foil and is followed by a carbonaceous sol-gel deposit. Galvano-static cycling and Electrochemical Impedance Spectroscopy measurements of super-capacitors all assembled with treated Al foil were tested over 10,000 cycles: an ESR of 0.5 {omega} cm{sup 2} and a capacitance of 95 F g{sup -1} of activated carbon are obtained and performances remain stable during cycling. The second part is devoted to the study of Carbon Nano Tubes (CNTs) adding into the active material on the performances of super-capacitors. A content of 15% of CNTs appears to be the best composition; the ESR is 0.4 {omega} cm{sup 2} (20% lowered as compared to a cell using activated carbon based electrode) and the capacitance remain high 93 F g{sup -1} of carbonaceous active material. (authors)

  4. Counter-current flow in a vertical to horizontal tube with obstructions

    Energy Technology Data Exchange (ETDEWEB)

    Tye, P.; Matuszkiewicz, A.; Teyssedou, A. [Institut de Genie Nucleaire, Quebec (Canada)] [and others

    1995-09-01

    This paper presents experimental results on counter-current flow and flooding in an elbow between a vertical and a horizontal run. The experimental technique used allowed not only the flooding limit to be determined, but also the entire partial delivery region to be studied as well. The influence that various size orifices placed in the horizontal run have on both the delivered liquid flow rates and on the flooding limits is also examined. It is observed that both the flooding limits and the delivered liquid flow rates decrease with decreasing orifice size. Further, it is also observed that the mechanisms that govern the partial delivery of the liquid are significantly different when an orifice is present in the horizontal leg as compared to the case when no orifice is present.

  5. Phenomenological modeling of eddy current signals with a view to characterizing steam generator tube flaws; Modelisation phenomenologique des signaux courants de Foucault en vue de la caracterisation des defauts des tubes de generateurs de vapeur

    Energy Technology Data Exchange (ETDEWEB)

    La, R

    1997-12-31

    This work deals with the eddy current non-destructive test ing. Its long-term goal is to design an `inverse model` for evaluating the geometry an d the dimensions of steam generator tube flaws from eddy current signals. The approach we adopted requires the preliminary knowledge of a `forward model` that estimates the eddy current signal knowing the geometry and the dimensions of the flaws. A quasi-exhaustive study of the existing forward models showed their inadequacy to solve the inverse problem. Hence, we proposed to build a general forward model, appropriate to the inversion. Using a parametric approach, this model is phenomenological, i.e. it is based on observations made from results of a finite element code. For each position of the coil, the proposed forward model fist discretized the eddy current distribution into `tubes of current`. A parametric description of the shape of these tubes is given according the system constituted of the coil and the tubes of current as a `multi-transformer`, their current signal, can then be deduced. The model was validated in the case of an axisymmetric configuration. Comparisons with both analytical and numerical models showed very good agreements. Then, the proposed model was applied to a three-dimensional configuration. Comparisons with experimental results are sufficiently conclusive to validate the approach to the construction of the phenomenological model. However, before envisaging the inverse problem, the computation time, still too long, ought to be reduced and the parametric description needs to be generalized to other three-dimensional configurations. (author). 92 refs.

  6. Comparison of characteristics parameters in the evaluation of wall thickness diminishing in admiralty brass tubes of the steam condenser, tested by eddy currents

    International Nuclear Information System (INIS)

    This work is aimed to appraise the measure of the wall thickness diminishing in the signals evaluation obtained in the inspection of steam condenser by eddy currents. In the analysis of the obtained signals were observed in the brass tubes a great quantity of internal defects whose signal indicates that there were diminishing of the wall thickness between 80% and 100%. With all this information and analyzing the data acquired, the tubes with more important indications were selected to make a more exhaustive study of the found defectology. As first test, it was measured the thickness of the worn tubes, comparing them with the original ones that are in stock. It was verified that the tubes separated for this study presented a 30% less thickness in comparison with the new tubes. A semiquantitative chemical test (EDAX) was made to verify if it was the same material. One of the extracted tubes (066 Y1) was reinspected in order to isolate the area with indications. Once this was performed, it was decided to cut the tube to make a visual inspection and to evaluate to what type of defect corresponds to the signals obtained. In the metallography it was confirm that it was a horseshoe type defect. When performing a dimensional control test of the found real defect, it was checked that the information obtained by eddy currents regarding the diminishing of the wall thickness diminishing was valid. At a last stage of the test, it was proceed to make an study and verification of the used parameters, probes, standards and finally determine which shall be the convenient modifications to minimize errors. (author)

  7. Effective dose and organ doses estimation taking tube current modulation into account with a commercial software package

    International Nuclear Information System (INIS)

    To evaluate the effect of including tube current modulation (TCM) versus using the average mAs in estimating organ and effective dose (E) using commercial software. Forty adult patients (24 females, 16 males) with normal BMI underwent chest/abdomen computed tomography (CT) performed with TCM at 120 kVp, reference mAs of 110 (chest) and 200 (abdomen). Doses to fully irradiated organs (breasts, lungs, stomach, liver and ovaries) and E were calculated using two versions of a dosimetry software: v.2.0, which uses the average mAs, and v.2.2, which accounts for TCM by implementing a gender-specific mAs profile. Student's t-test was used to assess statistically significant differences between organ doses calculated with the two versions. A statistically significant difference (p < 0.001) was found for E on chest and abdomen CT, with E being lower by 4.2 % when TCM is considered. Similarly, organ doses were also significantly lower (p < 0.001): 13.7 % for breasts, 7.3 % for lungs, 9.1 % for the liver and 8.5 % for the stomach. Only the dose to the ovaries was higher with TCM (11.5 %). When TCM is used, for the stylized phantom, the doses to lungs, breasts, stomach and liver decreased while the dose to the ovaries increased. (orig.)

  8. Effective dose and organ doses estimation taking tube current modulation into account with a commercial software package

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rendon, X. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); Bosmans, H.; Zanca, F. [KU Leuven, Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, Herestraat 49, box 7003, Leuven (Belgium); University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Oyen, R. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium)

    2015-07-15

    To evaluate the effect of including tube current modulation (TCM) versus using the average mAs in estimating organ and effective dose (E) using commercial software. Forty adult patients (24 females, 16 males) with normal BMI underwent chest/abdomen computed tomography (CT) performed with TCM at 120 kVp, reference mAs of 110 (chest) and 200 (abdomen). Doses to fully irradiated organs (breasts, lungs, stomach, liver and ovaries) and E were calculated using two versions of a dosimetry software: v.2.0, which uses the average mAs, and v.2.2, which accounts for TCM by implementing a gender-specific mAs profile. Student's t-test was used to assess statistically significant differences between organ doses calculated with the two versions. A statistically significant difference (p < 0.001) was found for E on chest and abdomen CT, with E being lower by 4.2 % when TCM is considered. Similarly, organ doses were also significantly lower (p < 0.001): 13.7 % for breasts, 7.3 % for lungs, 9.1 % for the liver and 8.5 % for the stomach. Only the dose to the ovaries was higher with TCM (11.5 %). When TCM is used, for the stylized phantom, the doses to lungs, breasts, stomach and liver decreased while the dose to the ovaries increased. (orig.)

  9. Can Automatic Abstracting Improve on Current Extracting Techniques in Aiding Users to Judge the Relevance of Pages in Search Engine Results?

    OpenAIRE

    Liang, SF

    2004-01-01

    Current search engines use sentence extraction techniques to produce snippet result summaries, which users may find less than ideal for determining the relevance of pages. Unlike extracting, abstracting programs analyse the context of documents and rewrite them into informative summaries. Our project aims to produce abstracting summaries which are coherent and easy to read thereby lessening users’ time in judging the relevance of pages. However, automatic abstracting technique has its domain ...

  10. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    Science.gov (United States)

    Segal, Christopher; Tarantini, Chiara; Hawn Sung, Zu; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-08-01

    High critical current density (J c) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a J c (12 T, 4.2 K) up to ∼2500 A mm‑2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ∼1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2–3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible J c must be addressed by forming the maximum fraction of high J c SG A15 and minimizing low J c large-grain (LG) A15 morphologies. In one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial J c improvement.

  11. The second eddy current testing of zircaloy tube samples from the OECD Halden reactor project at Reactor Fuel Examination Facility, Tokai, JAERI

    International Nuclear Information System (INIS)

    The Reactor Fuel Examination Facility in Tokai/JAERI (Japan Atomic Energy Research Institute) joined to the second round robin programme on eddy current test of the Halden/IFE. In the programme, two zircaloy tube samples with some artificial defects were provided for measurements. To clarify the locations in axial and azimuthal directions, types and dimensions of the provided artificial defects, measured signals from eddy current test were analysed in comparison with the known defects on the calibration tube. As a result, fourteen defects were determined from the measurements. Then, the location, the type and the relative dimension of them were also revealed. The results of those eddy current test are described in this paper. (author)

  12. TH-C-18A-10: The Influence of Tube Current On X-Ray Focal Spot Size for 70 KV CT Imaging

    International Nuclear Information System (INIS)

    Purpose: Focal spot blooming is an increase in the focal spot size at increased tube current and/or decreased tube potential. In this work, we evaluated the influence of tube current on the focal spot size at low kV for two CT systems, one of which used a tube designed to reduce blooming effects. Methods: A slit camera (10 micron slit) was used to measure focal spot size on two CT scanners from the same manufacturer (Siemens Somatom Force and Definition Flash) at 70 kV and low, medium and maximum tube currents, according to the capabilities of each system (Force: 100, 800 and 1300 mA; Flash: 100, 200 and 500 mA). Exposures were made with a stationary tube in service mode using a raised stand without table movement or flying focal spot technique. Focal spot size, nominally 0.8 and 1.2 mm, respectively, was measured parallel and perpendicular to the cathode-anode axis by calculating the full-width-at-half-maximum of the slit profile recording using computed radiographic plates. Results: Focal spot sizes perpendicular to the anode-cathode axis increased at the maximum mA by 5.7% on the Force and 39.1% on the Flash relative to that at the minimal mA, even though the mA was increased 13-fold on the Force and only 5- fold on the Flash. Focal spot size increased parallel to the anode-cathode axis by 70.4% on Force and 40.9% on Flash. Conclusion: For CT protocols using low kV, high mA is typically required. These protocols are relevant in children and smaller adults, and for dual-energy scanning. Technical measures to limit focal spot blooming are important in these settings to avoid reduced spatial resolution. The x-ray tube on a recently-introduced scanner appears to greatly reduce blooming effects, even at very high mA values. CHM has research support from Siemens Healthcare

  13. 粉状炸药大产能自动装药机研究%Analysis on Automatic Charging Machine of Plastic Tube Powdery Explosive of Large Capacity

    Institute of Scientific and Technical Information of China (English)

    白文忠; 任卫东; 刘静; 齐印川; 王木申

    2014-01-01

    Although its flowing disperse is good of powdery explosive, but it cannot finish the small cartridge charging just by its own gravity. For the purpose of rapid reload, the core technology of this research is to increase the flowing disperse during bulking of powdery explosive by using the theory of vibration of deflector and vibration punning. Besides, it cannot satisfy the charge density and the weight requirement of powdery explosive of loading in the medicine tube, it also need to vibration energy transfer to punning powdery explosive, eventually get the charge density conforms to the technological requirement. By using this way to realize propellant intrinsically safe, vibration propellant abolish the single tube driving structure in addition, and further simplification of the equipment, in theory, it can unlimitedly increase propellant tube number, conducive to productivity improvement.%粉状炸药的流散性较好,但不能仅仅依靠自身的重力完成小药卷装药。核心就是利用“振动导流、振动夯实”的原理,提高粉状炸药灌装时的流散性,而达到快速装填的目的。此外,装入药管内的粉状药,仅靠自流堆积填满,是无法满足装药密度及重量要求,也需要振动传递的能量来“夯实”药粉,最终获得符合工艺要求的装药密度。采用该途径来完成炸药灌装作业,彻底消除了摩擦生热的安全隐患,实现了装药本质安全,此外,震动装药取消了单管驱动结构,设备更加简化,理论上可以无限制增加装药管数量,有利于产能提高。

  14. Development of a system for monitoring and diagnosis of steam generator tubes using artificial intelligence techniques on Eddy Current Test signals

    International Nuclear Information System (INIS)

    New classification and feature extraction methods for steam generator tube defects are being developed by IPEN/CNEN-SP in cooperation with UTK to improve a monitoring and diagnosis system for classification and characterization of steam generator tube defects using Eddy Current Testing (ECT) signals. The first methodology being developed uses a set of feature extraction methods applied to different tube defect type ECT signals and each obtained feature vector is projected into a bi-dimensional map obtained by a Self-Organizing Map neural network. This methodology allows an optimal feature extraction method selection for the defect type classification. Other approach is being developed using tubes with different manufactured defect types which are tested using MIZ-17ET equipment with 4 sets of probes (two different diameter). A fuzzy inference system will be used to build a knowledge base for these defects. These methodology and algorithms will be integrated into an automated diagnosis system being developed with UTK, which is designed to read both on-line acquired data, as well as stored data files. These commercial software tools are the ones usually utilized in nuclear power plants. (author)

  15. Technical Note: Phantom study to evaluate the dose and image quality effects of a computed tomography organ-based tube current modulation technique

    International Nuclear Information System (INIS)

    Purpose: This technical note quantifies the dose and image quality performance of a clinically available organ-dose-based tube current modulation (ODM) technique, using experimental and simulation phantom studies. The investigated ODM implementation reduces the tube current for the anterior source positions, without increasing current for posterior positions, although such an approach was also evaluated for comparison. Methods: Axial CT scans at 120 kV were performed on head and chest phantoms on an ODM-equipped scanner (Optima CT660, GE Healthcare, Chalfont St. Giles, England). Dosimeters quantified dose to breast, lung, heart, spine, eye lens, and brain regions for ODM and 3D-modulation (SmartmA) settings. Monte Carlo simulations, validated with experimental data, were performed on 28 voxelized head phantoms and 10 chest phantoms to quantify organ dose and noise standard deviation. The dose and noise effects of increasing the posterior tube current were also investigated. Results: ODM reduced the dose for all experimental dosimeters with respect to SmartmA, with average dose reductions across dosimeters of 31% (breast), 21% (lung), 24% (heart), 6% (spine), 19% (eye lens), and 11% (brain), with similar results for the simulation validation study. In the phantom library study, the average dose reduction across all phantoms was 34% (breast), 20% (lung), 8% (spine), 20% (eye lens), and 8% (brain). ODM increased the noise standard deviation in reconstructed images by 6%–20%, with generally greater noise increases in anterior regions. Increasing the posterior tube current provided similar dose reduction as ODM for breast and eye lens, increased dose to the spine, with noise effects ranging from 2% noise reduction to 16% noise increase. At noise equal to SmartmA, ODM increased the estimated effective dose by 4% and 8% for chest and head scans, respectively. Increasing the posterior tube current further increased the effective dose by 15% (chest) and 18% (head

  16. Technical Note: Phantom study to evaluate the dose and image quality effects of a computed tomography organ-based tube current modulation technique

    Energy Technology Data Exchange (ETDEWEB)

    Gandhi, Diksha; Schmidt, Taly Gilat, E-mail: taly.gilat-schmidt@marquette.edu [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53201 (United States); Crotty, Dominic J.; Stevens, Grant M. [GE Healthcare, Waukesha, Wisconsin 53188 (United States)

    2015-11-15

    Purpose: This technical note quantifies the dose and image quality performance of a clinically available organ-dose-based tube current modulation (ODM) technique, using experimental and simulation phantom studies. The investigated ODM implementation reduces the tube current for the anterior source positions, without increasing current for posterior positions, although such an approach was also evaluated for comparison. Methods: Axial CT scans at 120 kV were performed on head and chest phantoms on an ODM-equipped scanner (Optima CT660, GE Healthcare, Chalfont St. Giles, England). Dosimeters quantified dose to breast, lung, heart, spine, eye lens, and brain regions for ODM and 3D-modulation (SmartmA) settings. Monte Carlo simulations, validated with experimental data, were performed on 28 voxelized head phantoms and 10 chest phantoms to quantify organ dose and noise standard deviation. The dose and noise effects of increasing the posterior tube current were also investigated. Results: ODM reduced the dose for all experimental dosimeters with respect to SmartmA, with average dose reductions across dosimeters of 31% (breast), 21% (lung), 24% (heart), 6% (spine), 19% (eye lens), and 11% (brain), with similar results for the simulation validation study. In the phantom library study, the average dose reduction across all phantoms was 34% (breast), 20% (lung), 8% (spine), 20% (eye lens), and 8% (brain). ODM increased the noise standard deviation in reconstructed images by 6%–20%, with generally greater noise increases in anterior regions. Increasing the posterior tube current provided similar dose reduction as ODM for breast and eye lens, increased dose to the spine, with noise effects ranging from 2% noise reduction to 16% noise increase. At noise equal to SmartmA, ODM increased the estimated effective dose by 4% and 8% for chest and head scans, respectively. Increasing the posterior tube current further increased the effective dose by 15% (chest) and 18% (head

  17. Eddy Current and Ultrasonic IRIS Signal Characteristics of Reboiler Tube by Using STS 316L Calibration Specimen

    International Nuclear Information System (INIS)

    In this study, a field applicability of reboiler tube was evaluated by comparing ECT signal with IRIS signal about wall loss rate and remaining wall thickness using worked austenite STS 316L ASME standard calibration tube. In the case of wall-loss rate, as a result, tolerance about flat bottom hole and 10% O D groove(ECT), 80% defect and 10% O D groove(IRIS) occurred up to ±15%. In the case of remaining wall thickness, ECT was satisfied with the both tolerance, but tolerance about 80% defect occurred up to ±15% in IRIS. Therefore, if the IRIS is performed for interpretation of non-relevant indication and measurement of wall-loss rate after ECT, reliability is supposed to be improved

  18. Automatic Condition Monitoring of Industrial Rolling-Element Bearings Using Motor’s Vibration and Current Analysis

    DEFF Research Database (Denmark)

    Yang, Zhenyu

    2015-01-01

    extensively studied under diverse operating conditions: different sensor locations, motor speeds, loading conditions, and data samples from different time segments. The experimental results showed the powerful capability of vibration analysis in the bearing point defect fault diagnosis. The current analysis...

  19. A system to automatically classify and name any individual genome-sequenced organism independently of current biological classification and nomenclature.

    OpenAIRE

    Marakeby, Haitham; Badr, Eman; Torkey, Hanaa; Song, Yuhyun; Leman, Scotland; Monteil, Caroline; Lenwood S. Heath

    2014-01-01

    A broadly accepted and stable biological classification system is a prerequisite for biological sciences. It provides the means to describe and communicate about life without ambiguity. Current biological classification and nomenclature use the species as the basic unit and require lengthy and laborious species descriptions before newly discovered organisms can be assigned to a species and be named. The current system is thus inadequate to classify and name the immense genetic diversity withi...

  20. Dose equations for shift-variant CT acquisition modes using variable pitch, tube current, and aperture, and the meaning of their associated CTDI{sub vol}

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Robert L., E-mail: rdixon@wfubmc.edu [Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States); Boone, John M. [Departments of Radiology and Biomedical Engineering, University of California Davis, Sacramento, California 95817 (United States); Kraft, Robert A. [Department of Biomedical Engineering, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States)

    2014-11-01

    Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDI{sub vol} is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDI{sub vol} formulae clearly identifies the source of their differences with the traditional CTDI{sub vol}. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)—all having the same scanner-reported CTDI{sub vol}. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the “local CTDI{sub vol}(z)” or “CTDI{sub vol} per slice” do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDI{sub vol} for the same lacks physical significance and relevance. Conclusions: While the traditional CTDI{sub vol} at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose

  1. Dose equations for shift-variant CT acquisition modes using variable pitch, tube current, and aperture, and the meaning of their associated CTDIvol

    International Nuclear Information System (INIS)

    Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDIvol is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDIvol formulae clearly identifies the source of their differences with the traditional CTDIvol. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)—all having the same scanner-reported CTDIvol. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the “local CTDIvol(z)” or “CTDIvol per slice” do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDIvol for the same lacks physical significance and relevance. Conclusions: While the traditional CTDIvol at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDIvol for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose distribution it purportedly represents. On the other hand, the

  2. Development and validation of a simulation tool dedicated to eddy current non destructive testing of tubes; Developpement d'un modele electromagnetique 3D pour la simulation du controle par Courants de Foucault de tubes en fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Reboud, Ch

    2006-09-15

    Eddy current testing (ECT) technique is widely used in industrial fields such as iron and steel industry. Dedicated simulation tools provide a great assistance for the optimisation of ECT processes. CEA and the Vallourec Research Center have collaborated in order to develop a simulation tool of ECT of tubes. The volume integral method has been chosen for the resolution of Maxwell equations in a stratified medium, in order to get accurate results with a computation time short enough to carry out optimisation or inversion procedures. A fast model has been developed for the simulation of ECT of non magnetic tubes using specific external probes. New flaw geometries have been modelled: holes and notches with flat bottom. Validations of the developments, which have been integrated to the CIVA platform, have been carried out using experimental data recorded in laboratory conditions and in. industrial conditions, successively. The integral equations derived are solved using the Galerkin variant of the method of moments with pulse functions as projection functions. In order to overcome some memory limitations, other projection functions have been considered. A new discretization scheme based on non-uniform B-Splines of degree 1 or 2 has been implemented, which constitutes an original contribution to the existing literature. The decrease of the mesh size needed to get a given accuracy on the result may lead to the simulation of more complex ECT configurations. (author)

  3. Effects of stoichiometric variation and cooling rate on the phase formation and critical current density of Bi-2223 powder-in-tube tapes made from aerosol precursor

    International Nuclear Information System (INIS)

    Powder-in-tube Bi-2223 is currently the most promising high-temperature superconductor that can be fabricated in long lengths by industrial processes, and is likely to be used as the conductor component in first-generation applications. Intensive investigations of these conductors have revealed that the critical current density of fully processed tapes is influenced by a large number of processing parameters. Among these are the thermomechanical processing schedule and the extent of Bi-2223 phase conversion. These parameters are, in turn, affected by the precursor stoichiometry. In this study, powder precursors with varying Cu content were prepared using an aerosol pyrolysis technique, and powder-in-tube conductors were fabricated using these precursors. Both fast and slow cooling rates were employed during thermomechanical processing, and different treatment schedules are correlated to the critical current density. The results indicate that the effect of excess Cu on Jc is minor compared to the large Jc enhancements obtained by employing one or more slow-cooling steps in the thermomechanical processing schedule. (author)

  4. Eddy-current guidance of the automatic inspection machine for the main vessel of the superphenix reactor

    International Nuclear Information System (INIS)

    The weld detector device is an eddy-current measurement system consisting of four dual sensors (absolute + differential types), and a control cabinet with eight analog channels. The system delivers all the signals required for computing the correct track of the MIR machine along the welds, irrespective of bend, temperature, width and type of the seam, junctions of seams

  5. Automatic sequences

    CERN Document Server

    Haeseler, Friedrich

    2003-01-01

    Automatic sequences are sequences which are produced by a finite automaton. Although they are not random they may look as being random. They are complicated, in the sense of not being not ultimately periodic, they may look rather complicated, in the sense that it may not be easy to name the rule by which the sequence is generated, however there exists a rule which generates the sequence. The concept automatic sequences has special applications in algebra, number theory, finite automata and formal languages, combinatorics on words. The text deals with different aspects of automatic sequences, in particular:· a general introduction to automatic sequences· the basic (combinatorial) properties of automatic sequences· the algebraic approach to automatic sequences· geometric objects related to automatic sequences.

  6. Comparison of standardized uptake values measured on 18F-NaF PET/CT scans using three different tube current intensities

    Directory of Open Access Journals (Sweden)

    Agnes Araujo Valadares

    2015-02-01

    Full Text Available Objective: To analyze standardized uptake values (SUVs using three different tube current intensities for attenuation correction on 18FNaF PET/CT scans. Materials and Methods: A total of 254 18F-NaF PET/CT studies were analyzed using 10, 20 and 30 mAs. The SUVs were calculated in volumes of interest (VOIs drawn on three skeletal regions, namely, right proximal humeral diaphysis (RH, right proximal femoral diaphysis (RF, and first lumbar vertebra (LV1 in a total of 712 VOIs. The analyses covered 675 regions classified as normal (236 RH, 232 RF, and 207 LV1. Results: Mean SUV for each skeletal region was 3.8, 5.4 and 14.4 for RH, RF, and LV1, respectively. As the studies were grouped according to mAs value, the mean SUV values were 3.8, 3.9 and 3.7 for 10, 20 and 30 mAs, respectively, in the RH region; 5.4, 5.5 and 5.4 for 10, 20 and 30 mAs, respectively, in the RF region; 13.8, 14.9 and 14.5 for 10, 20 and 30 mAs, respectively, in the LV1 region. Conclusion: The three tube current values yielded similar results for SUV calculation.

  7. Comparison of standardized uptake values measured on 18F-NaF PET/CT scans using three different tube current intensities

    International Nuclear Information System (INIS)

    Objective: to analyze standardized uptake values (SUVs) using three different tube current intensities for attenuation correction on 18FNaF PET/CT scans. Materials and methods: a total of 254 18F-NaF PET/CT studies were analyzed using 10, 20 and 30 mAs. The SUVs were calculated in volumes of interest (VOIs) drawn on three skeletal regions, namely, right proximal humeral diaphysis (RH), right proximal femoral diaphysis (RF), and first lumbar vertebra (LV1) in a total of 712 VOIs. The analyses covered 675 regions classified as normal (236 RH, 232 RF, and 207 LV1). Results: mean SUV for each skeletal region was 3.8, 5.4 and 14.4 for RH, RF, and LV1, respectively. As the studies were grouped according to mAs value, the mean SUV values were 3.8, 3.9 and 3.7 for 10, 20 and 30 mAs, respectively, in the RH region; 5.4, 5.5 and 5.4 for 10, 20 and 30 mAs, respectively, in the RF region; 13.8, 14.9 and 14.5 for 10, 20 and 30 mAs, respectively, in the LV1 region. Conclusion: the three tube current values yielded similar results for SUV calculation. (author)

  8. Radiation dose considerations by intra-individual Monte Carlo simulations in dual source spiral coronary computed tomography angiography with electrocardiogram-triggered tube current modulation and adaptive pitch

    Energy Technology Data Exchange (ETDEWEB)

    May, Matthias S.; Kuettner, Axel; Lell, Michael M.; Wuest, Wolfgang; Scharf, Michael; Uder, Michael [University of Erlangen, Department of Radiology, Erlangen (Germany); Deak, Paul; Kalender, Willi A. [University of Erlangen, Department of Medical Physics, Erlangen (Germany); Keller, Andrea K.; Haeberle, Lothar [University of Erlangen, Department of Medical Informatics, Biometry and Epidemiology, Erlangen (Germany); Achenbach, Stephan; Seltmann, Martin [University of Erlangen, Department of Cardiology, Erlangen (Germany)

    2012-03-15

    To evaluate radiation dose levels in patients undergoing spiral coronary computed tomography angiography (CTA) on a dual-source system in clinical routine. Coronary CTA was performed for 56 patients with electrocardiogram-triggered tube current modulation (TCM) and heart-rate (HR) dependent pitch adaptation. Individual Monte Carlo (MC) simulations were performed for dose assessment. Retrospective simulations with constant tube current (CTC) served as reference. Lung tissue was segmented and used for organ and effective dose (ED) calculation. Estimates for mean relative ED was 7.1 {+-} 2.1 mSv/100 mAs for TCM and 12.5 {+-} 5.3 mSv/100 mAs for CTC (P < 0.001). Relative dose reduction at low HR ({<=}60 bpm) was highest (49 {+-} 5%) compared to intermediate (60-70 bpm, 33 {+-} 12%) and high HR (>70 bpm, 29 {+-} 12%). However lowest ED is achieved at high HR (5.2 {+-} 1.5 mSv/100 mAs), compared with intermediate (6.7 {+-} 1.6 mSv/100 mAs) and low (8.3 {+-} 2.1 mSv/100 mAs) HR when automated pitch adaptation is applied. Radiation dose savings up to 52% are achievable by TCM at low and regular HR. However lowest ED is attained at high HR by pitch adaptation despite inferior radiation dose reduction by TCM. circle Monte Carlo simulations allow for individual radiation dose calculations. (orig.)

  9. Evaluation of automated attenuation-based tube current adaptation for coronary calcium scoring in MDCT in a cohort of 262 patients

    International Nuclear Information System (INIS)

    The aim of our study was to evaluate attenuation-based tube current adaptation in coronary calcium scoring using ECG-gated multi-detector-row CT (MDCT). A total of 262 patients underwent non-enhanced cardiac MDCT. Group 1 was scanned using a standard protocol with 120 kV and 150 mAseff. Groups 2-4 were scanned using an attenuation-based dose-adaptation template (CARE Dose) with different effective reference mAs settings (150, 180, 210 mAseff). Body-mass index (BMI) and CT-dose index values were calculated for each patient. Image noise and subjective image quality were assessed. Regression analysis was performed, and the variation coefficient of image noise was determined. Compared to the standard scan protocol a dose reduction of 31.1% for group 2 and 20.1% for group 3 was observed. Measurement variation of image noise was smaller for the attenuation-based dose adaptation protocols (group 2-4) (16.2-17.1%) compared to the standard scan protocol (32.3%). Regression analysis of groups 2-4 showed better correlation with improved dose usage based on BMI (all P ≤ 0.001). Median image quality was ''excellent'' in groups 2-4 and ''good'' in group 1. Automated attenuation-based tube current adaptation in coronary calcium scoring is technically feasible, can decrease patient dose, and reduces variation in image noise as a sign of improved dose usage. (orig.)

  10. Comparison of standardized uptake values measured on {sup 18}F-NaF PET/CT scans using three different tube current intensities

    Energy Technology Data Exchange (ETDEWEB)

    Valadares, Agnes Araujo; Woellner, Eduardo Bechtloff; Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto, E-mail: agnesvaladares@me.com [Universidade de Sao Paulo (HC/FMUSP), Sao Paulo, SP (Brazil). Fac. de Medicina. Hospital das Clinicas; Duarte, Paulo Schiavom; Coura-Filho, George Barberio [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil)

    2015-01-15

    Objective: to analyze standardized uptake values (SUVs) using three different tube current intensities for attenuation correction on {sup 18}FNaF PET/CT scans. Materials and methods: a total of 254 {sup 18}F-NaF PET/CT studies were analyzed using 10, 20 and 30 mAs. The SUVs were calculated in volumes of interest (VOIs) drawn on three skeletal regions, namely, right proximal humeral diaphysis (RH), right proximal femoral diaphysis (RF), and first lumbar vertebra (LV1) in a total of 712 VOIs. The analyses covered 675 regions classified as normal (236 RH, 232 RF, and 207 LV1). Results: mean SUV for each skeletal region was 3.8, 5.4 and 14.4 for RH, RF, and LV1, respectively. As the studies were grouped according to mAs value, the mean SUV values were 3.8, 3.9 and 3.7 for 10, 20 and 30 mAs, respectively, in the RH region; 5.4, 5.5 and 5.4 for 10, 20 and 30 mAs, respectively, in the RF region; 13.8, 14.9 and 14.5 for 10, 20 and 30 mAs, respectively, in the LV1 region. Conclusion: the three tube current values yielded similar results for SUV calculation. (author)

  11. Radiation dose considerations by intra-individual Monte Carlo simulations in dual source spiral coronary computed tomography angiography with electrocardiogram-triggered tube current modulation and adaptive pitch

    International Nuclear Information System (INIS)

    To evaluate radiation dose levels in patients undergoing spiral coronary computed tomography angiography (CTA) on a dual-source system in clinical routine. Coronary CTA was performed for 56 patients with electrocardiogram-triggered tube current modulation (TCM) and heart-rate (HR) dependent pitch adaptation. Individual Monte Carlo (MC) simulations were performed for dose assessment. Retrospective simulations with constant tube current (CTC) served as reference. Lung tissue was segmented and used for organ and effective dose (ED) calculation. Estimates for mean relative ED was 7.1 ± 2.1 mSv/100 mAs for TCM and 12.5 ± 5.3 mSv/100 mAs for CTC (P 70 bpm, 29 ± 12%). However lowest ED is achieved at high HR (5.2 ± 1.5 mSv/100 mAs), compared with intermediate (6.7 ± 1.6 mSv/100 mAs) and low (8.3 ± 2.1 mSv/100 mAs) HR when automated pitch adaptation is applied. Radiation dose savings up to 52% are achievable by TCM at low and regular HR. However lowest ED is attained at high HR by pitch adaptation despite inferior radiation dose reduction by TCM. circle Monte Carlo simulations allow for individual radiation dose calculations. (orig.)

  12. photomultiplier tubes

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  13. photomultiplier tube

    CERN Multimedia

    photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  14. Design of Automatic Welding Machine for Tube Plate Ring Weld of Tube Type Heat Exchanger and Welding Torch Orientation Simulation%管板式换热器管板环形焊缝自动焊机设计及焊枪定位仿真

    Institute of Scientific and Technical Information of China (English)

    徐向前; 周好斌; 王佳佳

    2015-01-01

    A simple, fast and precise positioning tube plate automatic welding machine was designed,according to the welding seam inaccurate positioning, low welding quality and efficiency in the tube plate seam welding of the tube plate exchanger during the welding process. The key of the welding machine is the localization and movement of the welding machine. The welding head is fixed on the gantry structure, and the stepping motor is used to drive the gantry structure and then the welding head's movement of two degrees of freedom is realized. The positioning of the welding head is realized by using CCD image processing. The design of the control system is completed based on C8051F020 MCU, and the human-computer interaction system includes the liquid crystal display and soft membrane 4 ×4 keyboard. Simulation by Matlab software, the center coordinates and radius of the pipe port circle can be obtained and welding head position can be achieved.%针对现有管板换热器管板环焊缝焊接过程中, 管板环焊缝定位不准确、 焊接质量和效率较低等问题, 设计了一种简单、 快捷、 定位精确的管板自动焊机. 焊接机头定位与移动是管板焊接的关键技术. 焊接机头固定在龙门架结构上, 采用步进电机驱动龙门架, 实现两自由度的运动; 利用CCD图像处理实现焊接机头的定位. C8051F020单片机作为主控芯片完成控制系统的设计, 液晶显示屏和4×4按键实现参数显示和设置. 通过Matlab软件仿真, 可获得钢管端口圆的半径和圆心坐标, 能够实现焊接机头定位.

  15. Increasing reliability of defect characterization on sg tubings using a combination of signal processing and expert system

    International Nuclear Information System (INIS)

    An expert system is developed for automatic analysis of eddy current signals provided by the multifrequency control of steam generators tubing. This article describes on one hand the aim and the results of the elimination of pilgrim noise, on the other hand the expert system which uses signal analysis and signal processing in unison

  16. Image quality and age-specific dose estimation in head and chest CT examinations with organ-based tube-current modulation.

    Science.gov (United States)

    Yamauchi-Kawaura, C; Yamauchi, M; Imai, K; Ikeda, M; Aoyama, T

    2013-12-01

    The purpose of this study was to investigate the effects of an organ-based tube-current modulation (OBTCM) system on image quality and age-specific dose in head and chest CT examinations. Image noise, contrast-to-noise ratio (CNR) and image entropy were assessed using statistical and entropy analyses. Radiation doses for newborn, 6-y-old child and adult phantoms were measured with in-phantom dosimetry systems. The quality of CT images obtained with OBTCM was not different from that obtained without OBTCM. In head CT scans, the eye lens dose decreased by 20-33 % using OBTCM. In chest CT scans, breast dose decreased by 5-32 % using OBTCM. Posterior skin dose, however, increased by 11-20 % using OBTCM in head and chest CT scans. The reduction of effective dose using OBTCM was negligibly small. Detailed image quality and dose information provided in this study can be effectively used for OBTCM application. PMID:23734058

  17. Characterization and implementation of OSL dosimeters for use in evaluating the efficacy of organ-based tube current modulation for CT scans of the face and orbits

    International Nuclear Information System (INIS)

    Purpose: The purpose of this work was to characterize commercially available optically stimulated luminescent (OSL) dosimeters for general clinical applications and apply the results to the development of a method to evaluate the efficacy of a vendor-specific organ-based tube current modulation application for both phantom and clinical computed tomography (CT) scans of the face and orbits. Methods: This study consisted of three components: (1) thorough characterization of the dosimeters for CT scans in phantom, including evaluations of depletion, fading, angular dependence, and conversion from counts to absorbed dose; (2) evaluation of the efficacy of using plastic glasses to position the dosimeters over the eyes in both phantom and clinical studies; and (3) preliminary dosimetry measurements made using organ-based tube current modulation in computed tomography dose index (CTDI) and anthropomorphic phantom studies. Results: (1) Depletion effects were found to have a linear relationship with the output of the OSL dosimeters (R2 = 0.96). Fading was found to affect dosimeter readings during the first two hours following exposure but had no effect during the remaining 60-h period observed. No significant angular dependence was observed for the exposure conditions used in this study (with p-values ranging from 0.9 to 0.26 for all t-tests). Dosimeter counts varied linearly with absorbed dose when measured in the center and 12 o’clock positions of the CTDI phantoms. These linear models of counts versus absorbed dose had overlapping 95% confidence intervals for the intercepts but not for the slopes. (2) When dosimeters were positioned using safety glasses, there was no adverse effect on image quality, and there was no statistically significant difference between this placement and placement of the dosimeters directly on the eyes of the phantom (p = 0.24). (3) When using organ-based tube current modulation, the dose to the lens of the eye was reduced between 19% and 43

  18. A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360° through anthropomorphic voxelized female chest and head (0° and 30° tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDIvol and multiplying by a physical CTDIvol measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30° relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate total organ doses calculated using our database are

  19. A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation

    Energy Technology Data Exchange (ETDEWEB)

    Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos; Schmidt, Taly Gilat [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States); Division of Imaging and Applied Mathematics (OSEL/CDRH), US Food and Drug Administration, Silver Spring, Maryland 20905 (United States); Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53233 (United States)

    2012-09-15

    Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360 Degree-Sign through anthropomorphic voxelized female chest and head (0 Degree-Sign and 30 Degree-Sign tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tables of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI{sub vol} and multiplying by a physical CTDI{sub vol} measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30 Degree-Sign relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate

  20. Characterization and implementation of OSL dosimeters for use in evaluating the efficacy of organ-based tube current modulation for CT scans of the face and orbits

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, R. M.; Silosky, M., E-mail: michael.silosky@ucdenver.edu [Department of Radiology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States)

    2015-04-15

    Purpose: The purpose of this work was to characterize commercially available optically stimulated luminescent (OSL) dosimeters for general clinical applications and apply the results to the development of a method to evaluate the efficacy of a vendor-specific organ-based tube current modulation application for both phantom and clinical computed tomography (CT) scans of the face and orbits. Methods: This study consisted of three components: (1) thorough characterization of the dosimeters for CT scans in phantom, including evaluations of depletion, fading, angular dependence, and conversion from counts to absorbed dose; (2) evaluation of the efficacy of using plastic glasses to position the dosimeters over the eyes in both phantom and clinical studies; and (3) preliminary dosimetry measurements made using organ-based tube current modulation in computed tomography dose index (CTDI) and anthropomorphic phantom studies. Results: (1) Depletion effects were found to have a linear relationship with the output of the OSL dosimeters (R{sup 2} = 0.96). Fading was found to affect dosimeter readings during the first two hours following exposure but had no effect during the remaining 60-h period observed. No significant angular dependence was observed for the exposure conditions used in this study (with p-values ranging from 0.9 to 0.26 for all t-tests). Dosimeter counts varied linearly with absorbed dose when measured in the center and 12 o’clock positions of the CTDI phantoms. These linear models of counts versus absorbed dose had overlapping 95% confidence intervals for the intercepts but not for the slopes. (2) When dosimeters were positioned using safety glasses, there was no adverse effect on image quality, and there was no statistically significant difference between this placement and placement of the dosimeters directly on the eyes of the phantom (p = 0.24). (3) When using organ-based tube current modulation, the dose to the lens of the eye was reduced between 19% and

  1. Evaluation of automated attenuation-based tube current adaptation for coronary calcium scoring in MDCT in a cohort of 262 patients

    Energy Technology Data Exchange (ETDEWEB)

    Muehlenbruch, Georg; Hohl, Christian; Das, Marco; Wildberger, Joachim E.; Thomas, Christoph; Guenther, Rolf W. [University Hospital (RWTH) Aachen, Department of Diagnostic Radiology, Aachen (Germany); Suess, Christoph; Klotz, Ernst; Flohr, Thomas [Siemens Medical Solutions, Computed Tomography, Forchheim (Germany); Koos, Ralf [University Hospital (RWTH) Aachen, Department of Cardiology, Aachen (Germany); Mahnken, Andreas H. [RWTH-Aachen University, Applied Medical Engineering, Helmholtz Institute, Aachen (Germany)

    2007-07-15

    The aim of our study was to evaluate attenuation-based tube current adaptation in coronary calcium scoring using ECG-gated multi-detector-row CT (MDCT). A total of 262 patients underwent non-enhanced cardiac MDCT. Group 1 was scanned using a standard protocol with 120 kV and 150 mAs{sub eff}. Groups 2-4 were scanned using an attenuation-based dose-adaptation template (CARE Dose) with different effective reference mAs settings (150, 180, 210 mAs{sub eff}). Body-mass index (BMI) and CT-dose index values were calculated for each patient. Image noise and subjective image quality were assessed. Regression analysis was performed, and the variation coefficient of image noise was determined. Compared to the standard scan protocol a dose reduction of 31.1% for group 2 and 20.1% for group 3 was observed. Measurement variation of image noise was smaller for the attenuation-based dose adaptation protocols (group 2-4) (16.2-17.1%) compared to the standard scan protocol (32.3%). Regression analysis of groups 2-4 showed better correlation with improved dose usage based on BMI (all P {<=} 0.001). Median image quality was ''excellent'' in groups 2-4 and ''good'' in group 1. Automated attenuation-based tube current adaptation in coronary calcium scoring is technically feasible, can decrease patient dose, and reduces variation in image noise as a sign of improved dose usage. (orig.)

  2. The criterion for blanking-off heat-transfer tubes in the steam generators at VVER-based nuclear power plants based on the results of eddy-current examination

    Science.gov (United States)

    Lunin, V. P.; Zhdanov, A. G.; Chegodaev, V. V.; Stolyarov, A. A.

    2015-05-01

    The problem of defining the criterion for blanking off heat-transfer tubes in the steam generators at nuclear power plants on the basis of signals obtained from the standard multifrequency eddy-current examination is considered. The decision about blanking off one or another tube is presently made with reference to one parameter of the relevant signal at the working frequency, namely, with reference to its phase, which directly depends on the depth of the flaw being detected, i.e., a crack in the tube. The crack depth equal to 60% of the tube wall thickness is regarded to be the critical one, at which a decision about withdrawing such a tube out from operation (blanking off) must be taken. However, since mechanical tensile rupture tests of heat-transfer tubes show the possibility of their further use with such flaws, the secondary parameter of the signal, namely, its amplitude, must be used for determining the blanking-off criterion. The signals produced by the standard flow-type transducers in response to flaws in the form of a longitudinal crack having the depth and length within the limits permitted by the relevant regulations were calculated using 3D finite-element modeling. Based on the obtained results, the values of the eddy-current signal amplitude were determined, which, together with the signal phase value, form a new amplitude-phase criterion for blanking off heat-transfer tubes. For confirming the effectiveness of this technique, the algorithm for revealing the signal indications satisfying the proposed amplitude-phase criterion was tested on real signals obtained from operational eddy-current examination of the state of steam generator heat-transfer tubes carried out within the framework of planned preventive repair.

  3. Automatic text summarization

    CERN Document Server

    Torres Moreno, Juan Manuel

    2014-01-01

    This new textbook examines the motivations and the different algorithms for automatic document summarization (ADS). We performed a recent state of the art. The book shows the main problems of ADS, difficulties and the solutions provided by the community. It presents recent advances in ADS, as well as current applications and trends. The approaches are statistical, linguistic and symbolic. Several exemples are included in order to clarify the theoretical concepts.  The books currently available in the area of Automatic Document Summarization are not recent. Powerful algorithms have been develop

  4. CT vs 68Ge attenuation correction in a combined PET/CT system: evaluation of the effect of lowering the CT tube current

    International Nuclear Information System (INIS)

    With the introduction of combined positron emission tomography/computed tomography (PET/CT) systems, several questions have to be answered. In this work we addressed two of these questions: (a) to what value can the CT tube current be reduced while still yielding adequate maps for the attenuation correction of PET emission scans and (b) how do quantified uptake values in tumours derived from CT and germanium-68 attenuation correction compare. In 26 tumour patients, multidetector CT scans were acquired with 10, 40, 80 and 120 mA (CT10, CT40, CT80 and CT120) and used for the attenuation correction of a single FDG PET emission scan, yielding four PET scans designated PET CT10-PET CT120. In 60 tumorous lesions, FDG uptake and lesion size were quantified on PET CT10-PET CT120. In another group of 18 patients, one CT scan acquired with 80 mA and a standard transmission scan acquired using 68Ge sources were employed for the attenuation correction of the FDG emission scan (PET CT80, PET 68Ge). Uptake values and lesion size in 26 lesions were compared on PET CT80 and PET 68Ge. In the first group of patients, analysis of variance revealed no significant effect of CT current on tumour FDG uptake or lesion size. In the second group, tumour FDG uptake was slightly higher using CT compared with 68Ge attenuation correction, especially in lesions with high FDG uptake. Lesion size was similar on PET CT80 and PET 68Ge. In conclusion, low CT currents yield adequate maps for the attenuation correction of PET emission scans. Although the discrepancy between CT- and 68Ge-derived uptake values is probably not relevant in most cases, it should be kept in mind if standardised uptake values derived from CT and 68Ge attenuation correction are compared. (orig.)

  5. Features of phase composition of stainless austenitic steels and possibility of selection tubes of these steels in accordance with their steel grades by means of eddy current method

    International Nuclear Information System (INIS)

    Studies on mechanical, magnetic and electric characteristics of some types of chromium-nickel and chromium-nickel-molybdenum austenitic steels used for manufacturing hot-rolled tubes are carried out. A possibility of nondestructive control of stainless austenitic steel by grades is disclosed. A mock-up of an eddy device with a superposed transformer for measurements on samples of tubes is described

  6. A Digital Ultrasonic and Eddy Current Inspection System for Nondestructive Examination of Precision Tubes and Bars%精密管棒材数字成像无损探伤和测量系统

    Institute of Scientific and Technical Information of China (English)

    蔡桂喜; 刘畅; 林俊明; 于冰; 董瑞琪

    2012-01-01

    精密管材和棒材广泛用于核能和航空航天等领域,其细微缺陷探伤和尺寸精密测量极为重要。为此研制了精密管棒材数字成像无损探伤和测量系统。该系统由超声纵、横向缺陷探伤、超声尺寸测量、涡流探伤等子系统组成,实现了管材内壁、外壁纵横向缺陷超声探伤,棒材内部缺陷超声纵波探伤,棒材纵向缺陷超声横波探伤;棒材周向、径向缺陷超声横波探伤;管材壁厚超声测量,管材、棒材直径超声测量,管材、棒材椭圆度超声测量;管材、棒材缺陷涡流穿过式探伤及异物(渗碳等)检测,管材、棒材材料背景噪声穿过式涡流检测,管材、棒材旋转点式涡流探伤。各检测子系统均依据轴向编码器和周向编码器进行缺陷检测和尺寸测量的时基线记录显示、B扫显示和C扫成像显示,实现了高灵敏度、高分辨力、高可靠性的管材和棒材无损检测。%In nuclear and aerospace industry the widely used precision tubes and bars needed to be inspectea in detail for tiny defects and dimension of wall-thickness and diameter. An automatic examination system is designed for this purpose which is with the function of the inspection and measurement. The system is composed of ultrasonic testing sub-system for inspecting longitudinal and circumferential defects, and ultrasonic measurement sub system and eddy-current testing sub-system. The defects which could be found are longitudinal and circumferential ID and OD in pipes with ultrasound shear wave, and internal defects in bars with ultrasound longitudinal wave, and longitudinal and circumferential defects in bars with ultrasound shear wave. The ultrasonic measurement sub-system could inspect the wall-thickness of pipes and the diameter and ellipticity of pipes and bars. With bobbin coil, the defects and pollution in pipes and bars could be inspected, and the noise signal of material could be inspected also. With the

  7. Topogram-based automated selection of the tube potential and current in thoraco-abdominal trauma CT - a comparison to fixed kV with mAs modulation alone

    Energy Technology Data Exchange (ETDEWEB)

    Frellesen, Claudia; Stock, Wenzel; Kerl, J.M.; Lehnert, Thomas; Wichmann, Julian L.; Beeres, Martin; Schulz, Boris; Bodelle, Boris; Vogl, Thomas J. [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Nau, Christoph; Geiger, Emanuel; Wutzler, Sebastian [Clinic of the Goethe University, Department of Trauma, Hand and Reconstructive Surgery, Frankfurt (Germany); Ackermann, Hanns [Clinic of the Goethe University, Department of Biostatistics and Mathematical Modelling, Frankfurt (Germany); Bauer, Ralf W. [Clinic of the Goethe University, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Klinikum der Goethe-Universitaet, Institut fuer Diagnostische und Interventionelle Radiologie, Frankfurt am Main (Germany)

    2014-07-15

    To investigate the impact of automated attenuation-based tube potential selection on image quality and exposure parameters in polytrauma patients undergoing contrast-enhanced thoraco-abdominal CT. One hundred patients were examined on a 16-slice device at 120 kV with 190 ref.mAs and automated mA modulation only. Another 100 patients underwent 128-slice CT with automated mA modulation and topogram-based automated tube potential selection (autokV) at 100, 120 or 140 kV. Volume CT dose index (CTDI{sub vol}), dose-length product (DLP), body diameters, noise, signal-to-noise ratio (SNR) and subjective image quality were compared. In the autokV group, 100 kV was automatically selected in 82 patients, 120 kV in 12 patients and 140 kV in 6 patients. Patient diameters increased with higher kV settings. The median CTDI{sub vol} (8.3 vs. 12.4 mGy; -33 %) and DLP (594 vs. 909 mGy cm; -35 %) in the entire autokV group were significantly lower than in the group with fixed 120 kV (p < 0.05 for both). Image quality remained at a constantly high level at any selected kV level. Topogram-based automated selection of the tube potential allows for significant dose savings in thoraco-abdominal trauma CT while image quality remains at a constantly high level. (orig.)

  8. Topogram-based automated selection of the tube potential and current in thoraco-abdominal trauma CT - a comparison to fixed kV with mAs modulation alone

    International Nuclear Information System (INIS)

    To investigate the impact of automated attenuation-based tube potential selection on image quality and exposure parameters in polytrauma patients undergoing contrast-enhanced thoraco-abdominal CT. One hundred patients were examined on a 16-slice device at 120 kV with 190 ref.mAs and automated mA modulation only. Another 100 patients underwent 128-slice CT with automated mA modulation and topogram-based automated tube potential selection (autokV) at 100, 120 or 140 kV. Volume CT dose index (CTDIvol), dose-length product (DLP), body diameters, noise, signal-to-noise ratio (SNR) and subjective image quality were compared. In the autokV group, 100 kV was automatically selected in 82 patients, 120 kV in 12 patients and 140 kV in 6 patients. Patient diameters increased with higher kV settings. The median CTDIvol (8.3 vs. 12.4 mGy; -33 %) and DLP (594 vs. 909 mGy cm; -35 %) in the entire autokV group were significantly lower than in the group with fixed 120 kV (p < 0.05 for both). Image quality remained at a constantly high level at any selected kV level. Topogram-based automated selection of the tube potential allows for significant dose savings in thoraco-abdominal trauma CT while image quality remains at a constantly high level. (orig.)

  9. Assessment of Left Ventricular Function and Volume in Patients Undergoing 128-Slice Coronary CT Angiography with ECG-Based Maximum Tube Current Modulation: a Comparison with Echocardiography

    International Nuclear Information System (INIS)

    To compare multi-detector CT (MDCT) using 128-slice coronary CT angiography (Definition AS+, Siemens Medical Solution, Forchheim, Germany) with ECG-based maximum tube current modulation with echocardiography for the determination of left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), end-systolic volume (ESV), as well as assessing coronary artery image quality and patient radiation dose. Thirty consecutive patients (M:F = 20:10: mean age, 57.9 ± 11.4 years) were referred for MDCT for evaluation of atypical chest pain. EF, EDV and ESV were determined for both MDCT and echocardiography, and the correlation coefficients were assessed. Coronary artery segment subjective image quality (1, excellent: 4, poor) and radiation dose were recorded. Left ventricular EF, EDV, and ESV were calculated by MDCT and echocardiography and the comparison showed a significant correlation with those estimated by echocardiography (p < 0.05). Consistently, the LVEFs calculated by MDCT and echocardiography were not statistically different. However, LV, EDV and ESV from MDCT were statistically higher than those from echocardiography (p < 0.05). The average image quality score of the coronary artery segment was 1.10 and the mean patient radiation dose was 3.99 ± 1.85 mSv. Although LV volume was overestimated by MDCT, MDCT provides comparable results to echocardiography for LVEF and LVV, with a low radiation dose

  10. Air-water tests on counter-current flow limitation at lower end of vertical pipes simulating lower part of steam generator U-tube

    International Nuclear Information System (INIS)

    Air-water tests on counter-current flow limitation (CCFL) were carried out using vertical pipes with the diameter of D=20 mm and a sharp lower edge which simulated the lower part of U-tubes in a steam generator. Flow patterns were observed to identify the location of CCFL occurrence, and effects of the pipe length L and the water level in the upper tank h on CCFL were measured under the conditions of L=100-700 mm and h=100-600 mm. As a result, CCFL appeared at the upper end under the conditions of L/D=5 and h/D=5, but at the lower end for L/D≥15 and h/D=5∼30. In the case of the CCFL occurrence at the lower end, L and h did not affect CCFL characteristics. Using the Wallis parameters, JG* and JL*, a CCFL correlation for the sharp lower edge was derived. The CCFL constant, which is the value of JG*1/2 at JL*1/2=0, was C=0.73±0.02. (author)

  11. Tube to tubesheet welding by electron beam for heat exchanger application

    International Nuclear Information System (INIS)

    The EB-process can successfully be used to weld in tubes into tubesheet also for those materials which are sensitiv to hot cracking. The range of qualified welding parameters has been evaluated based on a lot of metallographic and microanalysis inspections. To obtain reproducable and perfect welds a microcomputer controlled welding cycle is recommended using beam deflection, automatic seam tracking, beam current- and focus control. The results can be adopted to the specific conditions of mobile welding equipment with local vacuum. (orig.)

  12. Assessing nodule detection on lung cancer screening CT: the effects of tube current modulation and model observer selection on detectability maps

    Science.gov (United States)

    Hoffman, J. M.; Noo, F.; McMillan, K.; Young, S.; McNitt-Gray, M.

    2016-03-01

    Lung cancer screening using low dose CT has been shown to reduce lung cancer related mortality and been approved for widespread use in the US. These scans keep radiation doses low while maximizing the detection of suspicious lung lesions. Tube current modulation (TCM) is one technique used to optimize dose, however limited work has been done to assess TCM's effect on detection tasks. In this work the effect of TCM on detection is investigated throughout the lung utilizing several different model observers (MO). 131 lung nodules were simulated at 1mm intervals in each lung of the XCAT phantom. A Sensation 64 TCM profile was generated for the XCAT phantom and 2500 noise realizations were created using both TCM and a fixed TC. All nodules and noise realizations were reconstructed for a total of 262 (left and right lungs) nodule reconstructions and 10 000 XCAT lung reconstructions. Single-slice Hotelling (HO) and channelized Hotelling (CHO) observers, as well as a multislice CHO were used to assess area-under-the-curve (AUC) as a function of nodule location in both the fixed TC and TCM cases. As expected with fixed TC, nodule detectability was lowest through the shoulders and leveled off below mid-lung; with TCM, detectability was unexpectedly highest through the shoulders, dropping sharply near the mid-lung and then increasing into the abdomen. Trends were the same for all model observers. These results suggest that TCM could be further optimized for detection and that detectability maps present exciting new opportunities for TCM optimization on a patient-specific level.

  13. The nondestructive testing of tubes and pipes for nuclear application

    International Nuclear Information System (INIS)

    The directive of the Reactor Safety Commission demands for all materials which are provided for the pressure bearing enclosure of the refrigerant a nondestructive testing with sufficient sensibility. The specification 3201.1 for nuclear application as well as company-internal rules of important manufacturers regulate the requirements derived from the above direction for the NDT of tubes and pipes. For an objective and reproducible testing, equipments with defined characteristics are employed, based on internal specifications, testing equipments are fabricated and then checked with a special computerized test system. Moreover probes are controlled with regard to their acoustic and electric properties. The NDT of heat exchanger tubes and of pipes is given here as an example: Heat exchanger tubes: The tests include the inspection of longitudinal and transverse defects, wall thickness, dimension and tightness. In connection with the NDT, defect catalogues are set up. By this means the chosen test sensitivity is verified, and so the high quality of the tubes is assured. Specially developed eddy-current methods prove that such tested tubes are free of corrosion-causing phases. Pipes: The pipes are tested for longitudinal and transverse defects, for laminations and for wall thickness. To fulfil the demand for an objective and reproducible testing, there was developed and installed an automatic, computer-controlled ultrasonic equipment with 40 probes. Development trends: For the NDT of heat exchanger and boiler tubes an electrodynamic excited ultrasonic test system is evolved which is also able to test curved and installed tubes. The sophisticated testing technology is completed by a qualified education and training of NDT personnel. (orig.)

  14. Gastrostomy Tube (G-Tube)

    Science.gov (United States)

    ... endoscope (a thin, flexible tube with a tiny camera and light at the tip) inserted through the ... Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com

  15. Automatic Inductive Programming Tutorial

    OpenAIRE

    Aler, Ricardo

    2006-01-01

    Computers that can program themselves is an old dream of Artificial Intelligence, but only nowadays there is some progress of remark. In relation to Machine Learning, a computer program is the most powerful structure that can be learned, pushing the final goal well beyond neural networks or decision trees. There are currently many separate areas, working independently, related to automatic programming, both deductive and inductive. The first goal of this tutorial is to give to the attendants ...

  16. Development of a new tube-to-tubesheet welding type for FBR's heat exchangers

    International Nuclear Information System (INIS)

    The intermediate heat exchanger for exchanging heat between primary and secondary sodium and the steam generator are required to guarantee the performance and the reliability of construction over long term under the environment of high temperature sodium peculiar to a FBR. With the increase of power output of FBR plants, the number of heating tubes and the size of tube plates of the intermediate heat exchangers of shell and tube type increase. In order to improve the reliability and the production process of the tube to tube plate welding, a new method was developed, according to which heating tubes are inserted into tube plate holes by about their thickness, and the welding of perfect penetration is carried out internally with an automatic TIG welder. At the same time, in order to confirm the reliability of the welded joints by this method, the tests for evaluating the strength for short time and long term were carried out. It was confirmed that the satisfactory performance of the welded joints was able to be obtained, and the method would be applicable to actual heat exchangers. As for the nondestructive inspection of welded joints, the radiographic method was established, and ultrasonic and eddy current flaw detection methods are being developed now. (Kako, I.)

  17. Ear tube insertion

    Science.gov (United States)

    Myringotomy; Tympanostomy; Ear tube surgery; Pressure equalization tubes; Ventilating tubes; Ear infection - tubes; Otitis - tubes ... trapped fluid can flow out of the middle ear. This prevents hearing loss and reduces the risk ...

  18. Coiled tubing

    International Nuclear Information System (INIS)

    Oil and gas wells that flow on initial completion eventually reach a condition of liquid loading that kills the wells. This results form declining reservoir pressure, decreased gas volume (velocity), increased water production and other factors that cause liquids to accumulate at the bottom of the well and exert back pressure on the formation. This restricts or in some cases prevents fluid entry into the wellbore form the formation. Flowing production can be restored or increased by reducing surface backpressure, well bore stimulation, pressure maintenance or by installing a string of smaller diameter tubing. This paper reports on installation (hanging off) of a concentric string of coiled tubing inside existing production tubing which is an economically viable, safe, convenient and effective alterative for returning some of these liquid loaded )logged-up) wells to flowing status

  19. Critical current density and pinning behaviour of mono-core MgB2 wires prepared by internal magnesium diffusion and in-situ powder-in-tube method

    International Nuclear Information System (INIS)

    Highlights: • MgB2 wires produced by internal Mg diffusion and powder-in-tube method are analyzed. • Properties of the wires are investigated by magnetic and transport measurement. • Dominant difference between the wires is in critical current density. • Mg diffusion wire has up to 50 times higher Jc than powder-in-tube wire. - Abstract: Mono-core MgB2 wires were produced by internal magnesium diffusion (IMD) and in-situ powder-in-tube (PIT) technique. Hysteresis loops and magnetic relaxations were measured to calculate critical current density, Jcm (via Bean’s critical state model) and mean effective activation energy (via Anderson’s flux creep theory). To calculate Jcm of the IMD sample, the formulae for typical cylindrical sample geometry must have been modified properly with regard to IMD hollow cylinder geometry. Results for Jcm were compared to direct transport measurements. Also studied was the irreversibility field, Birr, and upper critical field, Bc2. It was found that the dominant difference between wires is in Jc. For the IMD sample, Jc was higher and less field-dependent than Jc of the PIT sample

  20. Ear Tubes

    Science.gov (United States)

    ... of the ear drum or eustachian tube, Down Syndrome, cleft palate, and barotrauma (injury to the middle ear caused by a reduction of air pressure, ... specialist) may be warranted if you or your child has experienced repeated ... fluid in the middle ear, barotrauma, or have an anatomic abnormality that ...

  1. Reference factor F(CT)Q and X ray tube ionization yield R(TUBE)Q

    International Nuclear Information System (INIS)

    The operational facility procedures in diagnostic radiology standardization and calibration, through the relation between the X ray tube current and the ionization chamber current in a radiation quality Q, shown the reference factor F(CT)Q as the reality estimate to the X ray tube ionization yield, R(TUBE)Q . (author)

  2. Vacuum and the electron tube industry

    Science.gov (United States)

    Redhead, P. A.

    2005-07-01

    The electron tube industry started with the patenting of the thermionic diode by John Ambrose Fleming in 1904. The vacuum technology used by the infant tube industry was copied from the existing incandescent lamp industry. The growing demands for electron tubes for the military in the first world war led to major improvements in pumps and processing methods. By the 1920s, mass production methods were developing to satisfy the demands for receiving tubes by the burgeoning radio industry. Further expansion in the 1930s and 1940s resulted in improvements in automatic equipment for pumping vacuum tubes leading to the massive production rates of electron tubes in the second world war and the following two decades. The demand for radar during the war resulted in the development of techniques for large-scale production of microwave tubes and CRTs, the latter technology being put to good use later in TV picture tube production. The commercial introduction of the transistor ended the massive demand for receiving tubes. This review concentrates on the vacuum technology developed for receiving tube production.

  3. 小孔径自动钨极氩弧焊在管板焊接中的应用%Application of small hole automatic GTAW for tube-sheet welding

    Institute of Scientific and Technical Information of China (English)

    孟震

    2011-01-01

    This paper introduced a new special welding machine and welding tooling for small hole inside wire filling of tube sheet joint in argon arc welding machine in the tube sheet welding through test and ensured groove preparation methods and welding procedure parameters,by the X-ray test,corrosion test,macro metallographic test,pulled off the test and so on which the results that were satisfactory with welding quality and product requirements.For later the small holes of wire filling welding provides certain theoretical basis for future.%介绍了一种专用于小孔内填丝的新型管板接头氩孤焊机和机头在管板焊接工作中的应用,通过多次规范试验验证并最终确定坡口制备方式和焊接规范参数,焊接后经过射线检测、腐蚀试验、宏观金相试验、拉脱试验等的验证,确保焊接接头获得满意的焊接质量,为以后小孔内填丝焊接制造技术提供了一定的理论基础.

  4. Automatic Radiation Monitoring in Slovenia

    International Nuclear Information System (INIS)

    Full text: The automatic radiation monitoring system in Slovenia started in early nineties and now it comprises measurements of: 1. External gamma radiation: For the time being there are forty-three probes with GM tubes integrated into a common automatic network, operated at the SNSA. The probes measure dose rate in 30 minute intervals. 2. Aerosol radioactivity: Three automatic aerosol stations measure the concentration of artificial alpha and beta activity in the air, gamma emitting radionuclides, radioactive iodine 131 in the air (in all chemical forms, - natural radon and thoron progeny, 3. Radon progeny concentration: Radon progeny concentration is measured hourly and results are displayed as the equilibrium equivalent concentrations (EEC), 4. Radioactive deposition measurements: As a support to gamma dose rate measurements - the SNSA developed and installed an automatic measuring station for surface contamination equipped with gamma spectrometry system (with 3x3' NaI(Tl) detector). All data are transferred through the different communication pathways to the SNSA. They are collected in 30 minute intervals. Within these intervals the central computer analyses and processes the collected data, and creates different reports. Every month QA/QC analysis of data is performed, showing the statistics of acquisition errors and availability of measuring results. All results are promptly available at the our WEB pages. The data are checked and daily sent to the EURDEP system at Ispra (Italy) and also to the Austrian, Croatian and Hungarian authorities. (author)

  5. Variable load automatically tests dc power supplies

    Science.gov (United States)

    Burke, H. C., Jr.; Sullivan, R. M.

    1965-01-01

    Continuously variable load automatically tests dc power supplies over an extended current range. External meters monitor current and voltage, and multipliers at the outputs facilitate plotting the power curve of the unit.

  6. Electron tube

    Energy Technology Data Exchange (ETDEWEB)

    Suyama, Motohiro (Hamamatsu, JP); Fukasawa, Atsuhito (Hamamatsu, JP); Arisaka, Katsushi (Los Angeles, CA); Wang, Hanguo (North Hills, CA)

    2011-12-20

    An electron tube of the present invention includes: a vacuum vessel including a face plate portion made of synthetic silica and having a surface on which a photoelectric surface is provided, a stem portion arranged facing the photoelectric surface and made of synthetic silica, and a side tube portion having one end connected to the face plate portion and the other end connected to the stem portion and made of synthetic silica; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the photoelectric surface, and made of synthetic silica; and an electron detector arranged on the projection portion, for detecting electrons from the photoelectric surface, and made of silicon.

  7. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  8. Straightening tubes

    International Nuclear Information System (INIS)

    Hexagonal wrapper tubes, especially for nuclear reactor core sub-assemblies, may suffer from unacceptable bow as a result of welding wear pads to the wrapper and heat treatment. Straightening of the bow is effected by a method wherein at each of a series of axially spaced locations the faces or vertices of the tube are measured relative to a reference to determine the direction of bow at the locations. From these measurements, the appropriate axial locations for the application of corrective loading can be determined, whereby by application of the loading at a selected face or vertex for such measurements the bow is reduced. Such loading, by an actuator, can be repeated at the locations until the bow is reduced to within tolerances. (author)

  9. 非介入技术在X光机管电流测量中的应用研究%Application of non-invasive technology in X-ray tube current measurement

    Institute of Scientific and Technical Information of China (English)

    黄平; 龚岚; 刘志宏

    2012-01-01

    X-ray machine is widely used in diagnostic radiology, radiotherapy, industrial testing and other related fields. It plays an important role in protecting the health of citizens and promoting social -economic ? Progress. As an important parameter of the intensity of X-ray, the current of X-ray tube has a major impact on the X-ray output quality, the clarity of pictures and other aspects. In order to ensure the accuracy of testing data and simplify the certification process, a testing method was designed on the basis of the non-invasive to measure the current of X-ray tube. Experimental results show that the method can accurately measure the X-ray tube's current.%X光机广泛应用于放射诊断、放射治疗、工业探伤等相关领域,在保障公民身体健康和促进社会经济进步方面发挥着重要作用.X光机管电流作为控制X射线强度的重要参数,对射线输出质量、拍片清晰度等方面产生重要影响.在保证检测数据准确、检定过程简易的情况下,设计采用了基于非介入式的X光机管电流测量方法,测试结果表明该方法能准确测量X光机管电流.

  10. Alternate tube plugging criteria for steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Cueto-Felgueroso, C.; Aparicio, C.B. [Tecnatom, S.A., Madrid (Spain)

    1997-02-01

    The tubing of the Steam Generators constitutes more than half of the reactor coolant pressure boundary. Specific requirements governing the maintenance of steam generator tubes integrity are set in Plant Technical Specifications and in Section XI of the ASME Boiler and Pressure Vessel Code. The operating experience of Steam Generator tubes of PWR plants has shown the existence of some types of degradatory processes. Every one of these has an specific cause and affects one or more zones of the tubes. In the case of Spanish Power Plants, and depending on the particular Plant considered, they should be mentioned the Primary Water Stress Corrosion Cracking (PWSCC) at the roll transition zone (RTZ), the Outside Diameter Stress Corrosion Cracking (ODSCC) at the Tube Support Plate (TSP) intersections and the fretting with the Anti-Vibration Bars (AVBs) or with the Support Plates in the preheater zone. The In-Service Inspections by Eddy Currents constitutes the standard method for assuring the SG tubes integrity and they permit the monitoring of the defects during the service life of the plant. When the degradation reaches a determined limit, called the plugging limit, the SG tube must be either repaired or retired from service by plugging. Customarily, the plugging limit is related to the depth of the defect. Such depth is typically 40% of the wall thickness of the tube and is applicable to any type of defect in the tube. In its origin, that limit was established for tubes thinned by wastage, which was the predominant degradation in the seventies. The application of this criterion for axial crack-like defects, as, for instance, those due to PWSCC in the roll transition zone, has lead to an excessive and unnecessary number of tubes being plugged. This has lead to the development of defect specific plugging criteria. Examples of the application of such criteria are discussed in the article.

  11. Perfection of processes of seamless steel tubes production

    Directory of Open Access Journals (Sweden)

    YU. G. Gulyayev

    2011-10-01

    Full Text Available The article first give a review more of hundret years long history of seamless steel tube production, especially during the last 15-20 years of the 20th century. Prolongation, article give technological indices for 4 mills (automatical, continuous mill, pilger, Assel, and perfectation of processes seamless steel tubes production at the begining of 21st century.

  12. Perfection of processes of seamless steel tubes production

    OpenAIRE

    Gulyayev, Yu. G.; Ilija Mamuzić; Shyfrin, Ye. I.; Buršak, M.; D. YU. Garmashev

    2011-01-01

    The article first give a review more of hundret years long history of seamless steel tube production, especially during the last 15-20 years of the 20th century. Prolongation, article give technological indices for 4 mills (automatical, continuous mill, pilger, Assel), and perfectation of processes seamless steel tubes production at the begining of 21st century.

  13. 煤矿低压电网漏电容性电流自动补偿研究%Research on Capacitive Current Automatic Compensation on Low Voltage Power Grid Leakage Protection of Coal Mine

    Institute of Scientific and Technical Information of China (English)

    徐国萍

    2014-01-01

    In neutral insulation low voltage power supply lines of coal mine,due to distributed capacitance exists, the leakage currents or personal electric shock currents exceed the limited safety value, and the changes of distributed capacitance easily cause the original system overcompensation or under compensation. The automatic compensation scheme of combining inductance the coarse adjustment with the fine adjustment is proposed on base of the minimum leakage currents closed loop control theory. Using single chip microcomputer control relay automatic switching magnetic amplifier is to achieve multi tap AC winding inductance step adjustment. The currents of magnetic amplifier DC winding are changed by single chip microcomputer control step motor to adjust potentiometer. The system attains stepless regulation of the inductance, so that the currents of distributed capacitance are completely compensated by the inductor currents of the magnetic amplifier. It has many advantages of fast compensation speed, high precision, short cycle, safety and easy operation during compensation process.%针对煤矿井下中性点绝缘低压供电线路中,由于电网对地分布电容的存在,使漏电电流或人身触电电流超过极限安全值,并且电网分布电容的多变容易引起原系统过补偿或欠补偿的情况,提出基于最小漏电电流闭环控制理论的电感量粗调和细调相融合的自动补偿方案,采用单片机控制继电器自动切换磁放大器多抽头交流绕组实现电感量有级调节,通过步进电机调节电位器改变磁放大器直流绕组的电流,实现电感量无级调节,从而使流过磁放大器的电感电流完全补偿电网分布电容的电流。该系统补偿速度快、精度高、调整周期短,补偿过程操作方便、安全。

  14. Jose Cabrera (Zorita) tube examination

    International Nuclear Information System (INIS)

    Jose Cabrera (Zorita) tube examination procedures are discussed. This plant continues to use phosphate water chemistry (sodium/phosphate ratio = 2.1). Three hot leg tube segments were pulled from the Jose Cabera (Zorita) plant in 1985. One tube had a field EC indication on the OD at the first tube support plate and the other two had field EC indications on their ID about 3 inches above the bottom of the tube sheet. All three tubes were initially sent to Battelle for preliminary NDE and decontamination. Segments of two tubes were sent to Westinghouse for destructive examination. The results of the laboratory eddy current and radiographic examinations are given. The results of the visual examinations are also given. The tube with OD indications was destructively examined and shallow intergranular pitting and intergranular attack, up to 2 mils deep, were found on the OD in the tube sheet region. Local areas of IGA, up to 5 mils deep, were found on the OD within the tube support plate region. A summary of this information together with supporting micrographs is given. It was hypothesized that a caustic crevice environment was the cause of this mild degradation. Shallow areas of thinning or wastage, up to 3 mils, were found just above the top of the tube sheet in the sludge pile region. Even more shallow wastage was found at the edges of support plate locations. This wastage is believed to be the remnant of early plant chemistry when a higher sodium/phosphate ratio and higher phosphate concentration were allowed

  15. Test Station for Measuring Aluminum Tube Geometrical Parameters

    CERN Document Server

    Oansea, D; Gongadze, A L; Gostkin, M I; Dedovich, D V; Evtoukhovitch, P G; Comanescu, B; Kotov, S A; Necsoiu, T; Potrap, I N; Rogalev, E V; Tskhadadze, E G; Chelkov, G A

    2001-01-01

    A test station for quality control of aluminum tube outer diameter and wall thickness is presented. The tested tubes are used for drift detector assembly of ATLAS (LHC, CERN) muon system. The outer diameter and wall thickness of aluminium tubes are measured by means of noncontact optical and ultrasonic methods respectively with the accuracy of 3 {\\mu}m. The testing process is automatic and interacts with the production data base.

  16. Development of numerical analysis for eddy current testing

    Energy Technology Data Exchange (ETDEWEB)

    Satake, Kouji; Morimoto, Kazuo [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Advanced Technology Research Center; Araki, Yasuo; Morimura, Hirokazu; Iwahashi, Youichi

    1994-11-01

    A symmetrical and three-dimensional steady state eddy current analysis code was developed to impove eddy current testing (ECT) for steam generator tubes. This code is formulated by FEM-BEM coupling techniques, which eliminate the need for mesh regeneration of the tube domain for every movement of the probe. The calculations were carried out under various conditions including those for various types of probe, defect orientations, etc. Compared with the experimental data, it was shown that it was feasible for actual application. Furthermore, we have developed a total eddy current analysis system (INSPECTOR: Integrated Numerical Analysis System to Perform Eddy Current Testing of Steam Generator) which consists of an ECT calculation code, an automatic mesh generator for analysis, a data base and display software for the calculated results. This system makes it easier to develop an ECT probe and evaluate ECT signals. (author).

  17. Methods of automatic scanning of SSNTDs

    International Nuclear Information System (INIS)

    The methods of automatic scanning of solid state nuclear track detectors are reviewed. The paper deals with transmission of light, charged particles, chemicals and electrical current through conventionally etched detectors. Special attention is given to the jumping spark technique and breakdown counters. Eventually optical automatic devices are examined. (orig.)

  18. Fuel cladding tubes and manufacture thereof

    International Nuclear Information System (INIS)

    Purpose: To enable smooth contaction between fuel pellets and cladding tubes, as well as prevent chemical reaction for the fission products released from the pellets. Method: The inner surface of a cladding tube is coated with a copper film and further provided thereover with a graphite film. The graphite film is formed through electrophoretic coating as follows: A cladding tube is supported rotatably in an electrophoretic coating tank containing coating solution incorporated with graphite powder and connected to an anode. A cathode is attached to the inside of the cladding tube. Coating current is supplied while rotating the cladding tube and the graphite film is formed through electrophoresis. (Ikeda, J.)

  19. Evaluation of automatic exposure control systems in computed tomography

    International Nuclear Information System (INIS)

    The development of the computed tomography (CT) technology has brought wider possibilities on diagnostic medicine. It is a non-invasive method to see the human body in details. As the CT application increases, it raises the concern about patient dose, because the higher dose levels imparted compared to other diagnostic imaging modalities. The radiology community (radiologists, medical physicists and manufacturer) are working together to find the lowest dose level possible, without compromising the diagnostic image quality. The greatest and relatively new advance to lower the patient dose is the automatic exposure control (AEC) systems in CT. These systems are designed to ponder the dose distribution along the patient scanning and between patients taking into account their sizes and irradiated tissue densities. Based on the CT scanning geometry, the AEC-systems are very complex and their functioning is yet not fully understood. This work aims to evaluate the clinical performance of AEC-systems and their susceptibilities to assist on possible patient dose optimizations. The approach to evaluate the AEC-systems of three of the leading CT manufacturers in Brazil, General Electric, Philips and Toshiba, was the extraction of tube current modulation data from the DICOM standard image sequences, measurement and analysis of the image noise of those image sequences and measurement of the dose distribution along the scan length on the surface and inside of two different phantoms configurations. The tube current modulation of each CT scanner associated to the resulted image quality provides the performance of the AECsystem. The dose distribution measurements provide the dose profile due to the tube current modulation. Dose measurements with the AEC-system ON and OFF were made to quantify the impact of these systems regarding patient dose. The results attained give rise to optimizations on the AEC-systems applications and, by consequence, decreases the patient dose without

  20. Tracheostomy tube - eating

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000464.htm Tracheostomy tube - eating To use the sharing features on ... when you swallow foods or liquids. Eating and Tracheostomy Tubes When you get your tracheostomy tube, or ...

  1. Wall thickness gauging device for moved glass tubes

    International Nuclear Information System (INIS)

    The invention has been aimed at a wall thickness gauging device for moved glass tubes on the basis of isotopic measuring techniques and can be applied to the glass tube production. Faulty measurements due to alterations of the glass tube position during the manufacturing process can be avoided. An auxiliary attachment has been established which makes it possible to detect position errors of the glass tube with regard to the measuring equipment and to carry out a correction of the measuring equipment position. By means of opto-electronic measuring equipment the position of tube edges is determined and in the case of a deviation from the prescribed position due to glass tube movement the wall thickness gauging device will automatically follow up the tube

  2. Critical current density and pinning behaviour of mono-core MgB2 wires prepared by internal magnesium diffusion and in-situ powder-in-tube method

    Science.gov (United States)

    Brunner, Boris; Kováč, Pavol; Reissner, Michael; Hušek, Imrich; Melišek, Tibor; Pardo, Enric

    2014-10-01

    Mono-core MgB2 wires were produced by internal magnesium diffusion (IMD) and in-situ powder-in-tube (PIT) technique. Hysteresis loops and magnetic relaxations were measured to calculate critical current density, Jcm (via Bean’s critical state model) and mean effective activation energy (via Anderson’s flux creep theory). To calculate Jcm of the IMD sample, the formulae for typical cylindrical sample geometry must have been modified properly with regard to IMD hollow cylinder geometry. Results for Jcm were compared to direct transport measurements. Also studied was the irreversibility field, Birr, and upper critical field, Bc2. It was found that the dominant difference between wires is in Jc. For the IMD sample, Jc was higher and less field-dependent than Jc of the PIT sample.

  3. Titanium condenser tubes

    International Nuclear Information System (INIS)

    The corrosion resistance of titanium in sea water is extremely excellent, but titanium tubes are expensive, and the copper alloy tubes resistant in polluted sea water were developed, therefore they were not used practically. In 1970, ammonia attack was found on the copper alloy tubes in the air-cooled portion of condensers, and titanium tubes have been used as the countermeasure. As the result of the use, the galvanic attack an copper alloy tube plates with titanium tubes as cathode and the hydrogen absorption at titanium tube ends owing to excess electrolytic protection were observed, but the corrosion resistance of titanium tubes was perfect. These problems can be controlled by the application of proper electrolytic protection. The condensers with all titanium tubes adopted recently in USA are intended to realize perfectly no-leak condensers as the countermeasure to the corrosion in steam generators of PWR plants. Regarding large condensers of nowadays, three problems are pointed out, namely the vibration of condenser tubes, the method of joining tubes and tube plates, and the tubes of no coolant leak. These three problems in case of titanium tubes were studied, and the problem of the fouling of tubes was also examined. The intervals of supporting plates for titanium tubes should be narrowed. The joining of titanium tubes and titanium tube plates by welding is feasible and promising. The cleaning with sponge balls is effective to control fouling. (Kako, I.)

  4. Study of the effect of the variation of automatic exposure control in computed tomography; Estudio del efecto de la variacion del control automatico de exposicion en tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Nersissian, D. Y.; Capeleti, F. F.; Furquin, T. A. C.; Melo, C. S.

    2011-07-01

    Teams computed tomography (CT) contain the current automatic control of exposure (CAE) which vary from the current X-ray tube in clinical protocols and deliver lower doses than those with fixed current. Alone is not enough control of dose, you need an acceptable image quality ensuring an accurate diagnosis. The TC regulate the flow of two ways: by considering the thickness of the patient and the attenuation by different tissues that intercept the x-ray Besides the advantage, there is the responsibility of proper use of different CAE systems, which require particular knowledge of each manufacturer of the CT.

  5. Automatic electromagnetic valve for previous vacuum

    International Nuclear Information System (INIS)

    A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

  6. Steam generator tube rupture analysis for the System 80+TM ALWR design

    International Nuclear Information System (INIS)

    This paper identifies the many preventative and mitigative features of the System 80+TM Advanced Light Water Reactor (ALWR) design that reduce the probability of radiological release to the atmosphere following hypothetical Steam Generator Tube Rupture (SGTR) events. This paper discusses studies performed to evaluate the response of the plant to SGTR events. The studies include a review of nine design changes which could potentially reduce the probability of SGTR containment bypass. The results show that the current System 80+TM design incorporates significant features which (1) reduce the risk of incurring a SGTR event, (2) significantly improve event diagnosis and mitigation, and (3) accommodate hypothetical multiple tube ruptures using automatic means. Thus, reliance on speedy manual corrective measures by the plant operators is significantly reduced. (author)

  7. Ultrasonic-test-equipment for rotation tubes

    International Nuclear Information System (INIS)

    The paper describes specifications and the configuration of a ultrasonic equipment for the testing of spinning tubes. Specifications: - Flaw detection inside and outside (resolution of 5μm), Wa-1 thickness measurement (accuracy +- 1,5μ), inner diameter measurement (accuracy +- 20μ), On-Line data processing, equipment completely automatic controlled. The results concerning measurement accuracy, reproducibility and stability during test conditions are presented. (orig.)

  8. photomultiplier tube

    CERN Multimedia

    A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  9. photomultiplier tube

    CERN Multimedia

    Philips. 150AVP. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

  10. Framatome recent developments and application on site in NDE of steam generator tubes

    International Nuclear Information System (INIS)

    The increasing needs concerning the follow up and expertise of PWR steam generator (SG) tubing have led Framatome to develop a quick on-site intervention mobile unit, which could implement any current technique and equipment. Besides, Framatome has developed several non destructrive examination methods to solve the specific problems encountered in service on the SG tubes: profilometry of the SG tubes by eddy current. Inside and above the tube sheet, eddy current inspection of tube sleeving by ultrasonic testing and eddy current

  11. Automatic input rectification

    OpenAIRE

    Long, Fan; Ganesh, Vijay; Carbin, Michael James; Sidiroglou, Stelios; Rinard, Martin

    2012-01-01

    We present a novel technique, automatic input rectification, and a prototype implementation, SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process correctly. When given an atypical input that does not satisfy these constraints, SOAP automatically rectifies the input (i.e., changes the input so that it satisfies the learned constraints). The goal is to automatically convert potentially dangerous inputs into typical inputs that the ...

  12. Automatic Fiscal Stabilizers

    Directory of Open Access Journals (Sweden)

    Narcis Eduard Mitu

    2013-11-01

    Full Text Available Policies or institutions (built into an economic system that automatically tend to dampen economic cycle fluctuations in income, employment, etc., without direct government intervention. For example, in boom times, progressive income tax automatically reduces money supply as incomes and spendings rise. Similarly, in recessionary times, payment of unemployment benefits injects more money in the system and stimulates demand. Also called automatic stabilizers or built-in stabilizers.

  13. Assessment and management of ageing of major nuclear power plant components important to safety: CANDU pressure tubes

    International Nuclear Information System (INIS)

    The report documents the current practices for assessment and management of the ageing of the pressure tubes in CANDU reactors and Indian PHWTRs. Chapter headings are: fuel channel and pressure tube description, design basis for the fuel channel and pressure tube, degradation mechanisms and ageing concerns for pressure tubes, inspection and monitoring methods for pressure tubes,assessment methods and fitness-for-service guidelines for pressure tubes, mitigation methods for pressure tubes, and pressure tube ageing management programme

  14. Automatic differentiation bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, G.F. (comp.)

    1992-07-01

    This is a bibliography of work related to automatic differentiation. Automatic differentiation is a technique for the fast, accurate propagation of derivative values using the chain rule. It is neither symbolic nor numeric. Automatic differentiation is a fundamental tool for scientific computation, with applications in optimization, nonlinear equations, nonlinear least squares approximation, stiff ordinary differential equation, partial differential equations, continuation methods, and sensitivity analysis. This report is an updated version of the bibliography which originally appeared in Automatic Differentiation of Algorithms: Theory, Implementation, and Application.

  15. Optimization of recommendations for abdomen computerized tomography based on reconstruction filters, voltage and tube current; Otimizacao de protocolos de tomografia computadorizada de abdome com base nos filtros de reconstrucao, tensao e corrente do tubo

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Vinicius da Costa

    2015-07-01

    The use of computed tomography has increased significantly over the past decades. In Brazil the use increased more than twofold from 2008 to 2014, in the meantime the abdomen procedures have tripled. The high frequency of this procedure combined by the increasing collective radiation dose in medical exposures, has resulted development tools to maximize the benefit in CT images. This work aimed to establish protocols optimized in abdominal CT through acquisitions parameters and reconstructions techniques based on filters kernels. A sample of patients undergoing abdominal CT in a diagnostic center of Rio de Janeiro was assessed. Had been collected patients information and acquisitions parameters. The phantoms CT image acquisitions were performed by using different voltage values by adjusting the tube current (mAs) to obtain the same value from CTDI{sub vol} patients with normal BMI. Afterwards, the CTDIvol values were reduced by 30%, 50% and 60%. All images were reconstructed with low-contrast filters (A) and standard filters (B). The CTDIvol values for patients with normal BMI were 7% higher than in patients with underweight BMI and 30%, 50% and 60% lower than the overweight, obese I and III patients, respectively. The evaluations of image quality showed that variation of the current (mA) and the reconstruction filters did not affect the Hounsfield values. When the contrast-to-noise ratio (CNR) was normalized to CTDIvol, the protocols acquired with 60% reduction of CTDIvol with 140 kV and 80 kV showed CNR 6% lower than the routine. Modifications of the acquisition parameters did not affect spatial resolution, but the post-processing with B filters reduced the spatial frequency by 16%. With reduced the dose of 30%, lesions in the spleen had the CNR higher than 10% routine protocols with 140 kV acquired and post-processed to filter A. The image post-processing with a filter A with a 80kV voltage provided CNR values equal to the routine for the liver lesions with a 30

  16. Photo-multiplier tube adjusting system's better design

    International Nuclear Information System (INIS)

    For solving using problems on photo-multiplier tube adjusting and testing experiments, we study the structure of tube and the principle of it. We improve its circuit design which can avoid the mistrigger on the oscilloscope display to get a serious of true data messages. At the same time, it supplies the timer control. This design can strong the stability of adjusting system, improve the test efficiency and automatization level. (authors)

  17. Development of INCONEL 600 precision tube (1)

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Yeong Han; Jo, Bong Hyeon; Lee, Dong Hee; Kim, Wan Kyo; Jeong, Pyeong Keun; Yoon, Hwang Lo; Chio, Seok Sik [Sammi Steel Co. Ltd., Changwon (Korea, Republic of)

    1994-07-01

    Steam generator, being connected with nuclear fuel reactor is one of the most important part of nuclear power plant and consists of a large number of INCONEL 600 tubes. Approximately 160 tons of tubes are needed for a single nuclear power plant. All of INCONEL 600 steam generator tubes for domestic nuclear power plants have been imported. The aim of this research is to develop INCONEL 600 precision tubes for steam generator of nuclear power plant. If this research is conducted successfully, we can produce nuclear fuel tubes, Ni-alloy precision tubes and stainless steel precision tubes for many purposes and technology of INCONEL 600 steam generator tubes are similar to those of other tubes above mentioned. In the current study, development of preliminary manufacturing process of INCONEL 600 precision tubes for steam generator and investigation of material`s metallurgical characteristics were conducted. The main scope of this research is as follows. First, the preliminary manufacturing process design was conducted after investigations of foreign manufacturing processes and technical reports. Second, the results of investigations of material`s metallurgical characteristics through the manufacturing process were applied to the production technology of tentative INCONEL 600 precision tubes for sample. Third, preliminary process routes were established and samples of INCONEL 600 precision tube were produced by this process. As the results of this research, 14 pieces of INCONEL 600 precision tubes were produced by preliminary manufacturing process and the material`s metallurgical characteristics were investigated through the processes. But the SCC test could not be conducted due to the absence of equipment. In order to apply the results of SCC test to the manufacturing process, we need a SCC tester which can simulate SCC characteristics under high temperature and high pressurized circulating water. 95 refs., 55 figs., 20 tabs.

  18. Photomultiplier tubes for Low Level Cerenkov Detectors

    International Nuclear Information System (INIS)

    Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a β-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10-12 input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10-12 to 10-9 input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses

  19. Photomultiplier tubes for Low Level Cerenkov Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O.

    1965-03-15

    Tube backgrounds of several 2-inch photomultiplier types having S11, 'S' , S13 and S20 cathodes are compared by measuring signal and background pulse height distributions at pulse heights corresponding to a few photo-electrons. The reference signal is generated by means of a {beta}-source and a plexiglass radiator. It is found that comparatively good results are obtained with selected tubes of the EMI types 6097B and 9514B having equivalent dark current dc values down to 10{sup -12} input lumens. Special interest is devoted to the correlation between the measured tube backgrounds and the dark current dc values of the tubes, as a good correlation between these parameters simplifies the selection of photomultiplier tubes. The equivalent dark currents of the tested tubes extend over the range 10{sup -12} to 10{sup -9} input lumens. Although the investigation deals with photomultiplier tubes intended for use in low level Cerenkov detectors it is believed that the results could be valuable in other fields where photomultiplier tubes are utilized for the detection of weak light pulses.

  20. Improvement of the HANATM-4 Tubing Workability

    International Nuclear Information System (INIS)

    HANATM cladding has been developed for high burn-up fuel cladding exceeding 70,000 MWD/MTU. HIPER fuels using HANATM-6 material are currently being conducted in-reactor test in commercial nuclear reactors. HANATM-6 was produced successfully for the fuel tubing by KEPCO NF. However, the production of fuel tubing of HANATM-4 has not reached to target yield due to cracking during tube pilgering. The purpose of this study has been carried out to improve workability of HANATM-4 tubing. An improvement on the manufacturing parameters and the alloy compositions adjustments in order to improve workability HANATM-4 tubing was performed in the producing HANATM-4 cladding successfully without cracking. However, it is necessary to minor change the design of Mandrel and Die to improve the surface quality. The effects on corrosion properties and microstructure by an adjustment in manufacturing parameters and alloy compositions are currently being evaluated

  1. Automation of the Tube-Thickness Measurements Using Ultrasonics

    International Nuclear Information System (INIS)

    Two ultrasonic methods for automatically measuring the wall thickness of thin-walled metal tubing are described and compared for accuracy and measurement rate. These methods are: (a) A double-probe method using an ultrasonic plane transmitter crystal to irradiate a small area of tube wall and a separate receiving crystal adjusted to receive energy from this same area; the two probes are mounted close to each other. As the transmitter frequency is varied, the receiver output shows an absorption resonance when the ultrasonic wavelength corresponds to twice the tube thickness. The paper describes the electronic circuits used to automatically adjust the frequency to keep the receiver output at minimum. By measuring this frequency a record in digital form of the thickness of the tube may be obtained. (b) A single-probe method using a focused transmitter probe directing a burst of energy, typically 30 μs duration of 5 MHz frequency, at normal incidence to the tube wall; the same probe acts as a receiver and electronic circuits are used to select the first reflected pulses. The paper describes how the transmitter frequency is varied automatically over a selected range and how the frequency at which a minimum reflected pulse occurs is selected and measured. This minimum occurs at a wavelength of twice the tube wall thickness so that again a direct digital measurement of thickness is achieved. (author)

  2. Test and Design of Current Comparator Bridge’s Automatic Balancing Algorithm%电流比较仪式电桥自动平衡算法设计与测试

    Institute of Scientific and Technical Information of China (English)

    陆沈敏; 李刚; 赵刚

    2013-01-01

      This paper designs an automatic balancing algorithm of current comparator bridge to get dielectric loss tanδ and capacitance. In order to eliminate unbalanced state between test capacitor arm and standard capacitor arm, the algorithm outputs the parameter (N2 turns & gain β) to make output voltage tend to zero by measuring the null detector output voltage and current of standard capacitor bridge arm. And it also uses Newton-Raphson iteration method to get more accurate parameter and then calculate tanδand capacitance value. This paper tests the capability of the algorithm in a condition of the power with stable frequency, changing frequency and AC power waveform mixed harmonics. The result shows that this algorithm has high precision and good stability.%  设计了电流比较仪式电桥的自动平衡算法,可测量电容器介质损耗角正切值及电容值。本算法是为了矫正试品电容器与标准电容器桥臂间的不平衡状态,通过测量标准电容器桥臂电流和检零计输出电压,输出匝数N2和增益β两个平衡参数,使检零计输出趋零。算法基于牛顿拉夫逊迭代方法,可由输出电压值修正得到精度更高的平衡参数,并用电桥平衡后的参数计算出正切值及电容值。本文测试了在电源频率偏差、频率波动、电源波形参杂谐波等多种条件下的性能,表明该算法精度高,稳定性好。

  3. Pressurized drift tubes scintillating fiber hadron calorimetry. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bromberg, C.; Huston, J.; Miller, R. [and others

    1995-03-22

    Under this contract members of the MSU high energy physics group constructed a full-scale Pressurized Drift Tube Chamber intended for the GEM muon system at the SSC. They achieved a position resolution of <90 {mu} over the full 5 m{sup 2} area of the detector. This resolution satisfied the GEM resolution requirements of <100 {mu} by a comfortable margin. Based on their SSC work they developed a new technique for creating wire supports in drift tubes with an overall placement accuracy of <20 {mu}. This technique requires only simple jigging and can be duplicated and operated at low cost. Also, they participated in the design and testing of a hadron calorimeter prototype for GEM. This work lead the authors to develop a semi-automatic welding machine to fuse together two plastic optical fibers. Copies of this machine are currently in use in the CDF endplug upgrade at Fermilab and additional copies are used widely in calorimeter and fiber-tracker construction.

  4. Development of ultrasonic testing scanner for NPP steam generator tubes (I)

    Energy Technology Data Exchange (ETDEWEB)

    Shin, J. I.; Huh, H

    1998-12-01

    Testing tubes are designed and fabricated to investigate the optimum test conditions through the various experiments. The proto-type P/C-controlled automatic rotating scanner is fabricated to obtain the ultrasonic data automatically from test tubes. It was attempted to visualize the shape of defects presented inside the specimen using peak amplitude at each point. However, further research works will be needed to be applied at the plant site as a more reliable technology.

  5. Development of ultrasonic testing scanner for NPP steam generator tubes (I)

    International Nuclear Information System (INIS)

    Testing tubes are designed and fabricated to investigate the optimum test conditions through the various experiments. The proto-type P/C-controlled automatic rotating scanner is fabricated to obtain the ultrasonic data automatically from test tubes. It was attempted to visualize the shape of defects presented inside the specimen using peak amplitude at each point. However, further research works will be needed to be applied at the plant site as a more reliable technology

  6. Neural Tube Defects

    Science.gov (United States)

    Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the first month ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In spina bifida, ...

  7. Tracheostomy tube - speaking

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000465.htm Tracheostomy tube - speaking To use the sharing features on ... are even speaking devices that can help you. Tracheostomy Tubes and Speaking Air passing through vocal cords ( ...

  8. Development of a SG Tube Inspection/maintenance Robot

    International Nuclear Information System (INIS)

    A radiation hardened robot system is developed which assists in an automatic non-destructive testing and the repair of nuclear steam generator tubes. And a control system is developed. For easy carriage and installation, the robot system consists of three separable parts: a manipulator, a water chamber entering and leaving device of the manipulator and a manipulator base pose adjusting device. The kinematic analysis using the grid method was performed to search for the optimal manipulator's link parameters, and the stress analysis of the robotic system was also carried out for a structural safety verification. The robotic control system consists of a main personal computer placed near the operator and a local robotic position controller placed near the steam generator. A software program to control and manage the robotic system has been developed on the NT based OS to increase the usability. The software program provides a robot installation function, a robot calibration function, a managing and arranging function for the eddy-current test, a real time 3- D graphic simulation function which offers a remote reality to operators and so on. The image information acquired from the camera attached to the end-effector is used to calibrate the end-effector pose error and the time-delayed control algorithm is applied to calculate the optimal PID gain of the position controller. Eddy-current probe guide devices, a brushing tool, a motorized plugging tool and a U-tube internal visual inspection system have been developed. A data acquisition system was built to acquire and process the eddy-current signals, and a software program for eddy-current signal acquisition and processing. The developed robotic system has been tested in the Ulchin NPP type steam generator mockup in a laboratory. The final function test was carried out at the Kori Npp type steam generator mockup in the Kori training center

  9. Development and formability analysis of TRIP seamless steel tube

    Institute of Scientific and Technical Information of China (English)

    Zhang Zicheng; Zhu Fuxian

    2014-01-01

    In this paper, the production technology of transformation induced plasticity (TRIP) steel was first introduced into the steel tube manufacture field to produce the steel tubes with high strength and plasticity. The TRIP seamless steel tubes with the microstructure of ferrite, bainite, retained austenite and a little martensite were successfully fabricated using a cold-drawn steel tube with two-stage heat treatment technique and continu- ous heat treatment process, respectively. The ring tensile test and cold bend test were carried out to study the formability of the newly developed TRIP seamless steel tube. The results showed that the TRIP seamless steel tubes have a good cold formability, and they are available to be used in the tube hydroforming process. In ad- dition, the equipment of continuous heat treatment developed in the current study can be used to produce TRIP steel tube, and it may serve as an important reference for the industrial production of TRIP steel tube.

  10. Measurement of linearity and time response parameters for photomultiplier tube

    International Nuclear Information System (INIS)

    In this paper, methods of testing linearity and time response parameters of photomultiplier tube are introduced and illustrated. Two ways of measuring the maximum anode impulse current of photomultiplier tube are contrasted. Suitable scopes of these two methods are acquired under different circumstances. At the same time, the electron transit time of photomultiplier tube is obtained by means of cable delays. (authors)

  11. Development of the boiler tube wall thickness ultrasonic detector

    International Nuclear Information System (INIS)

    Wall thickness of fossil fuel firing power boiler tubes are measured by ultrasonic test at regular intervals as part of in-service inspections. The measuring tubes are located high up on the boiler and at restricted sites, and many man-hours are required for preparatory of boiler tube wall thickness scale removal. To improve the efficiency and reliability of boiler tube wall thickness measurements, a system was developed for measuring the tube wall thickness by ultrasonic test from inside the tube. The primary features of this system are: 1) polishing on the outersurface of boiler tubes is not necessary because measurements are made from inside. (Reduction of man-hours), 2) measurements in limited places where manual measurement is difficult or impossible is made possible because automatic measurement from inside the tube is made by an ultrasonic probe introduced into the tube from the inspection hole of the header. (Improvement of reliability), and 3) the tube wall thickness is measured by a submerged ultrasonic rotary probe at an accuracy of ±0.1 mm along the full length. (Improvement of reliability)

  12. Gastrostomy feeding tube - bolus

    Science.gov (United States)

    ... a gastrostomy tube. Delmar’s Fundamental and Advanced Nursing Skills . 2nd Ed. Albany, NY: Delmar Thomson Learning; 2003: 742-749. Simmons, Remmington R.The percutaneous endoscopic gastrostomy tube: a nurse's guide to PEG tubes. Medsurg Nurs . 2013 Mar- ...

  13. KER-2 tube history

    Energy Technology Data Exchange (ETDEWEB)

    Banister, W.C.

    1963-08-16

    Zirconium process tube No. 1986 was installed in KE Reactor tube channel No. 2864 on April 16, 1959. This report describes the history and the conditions to which it was exposed during its residence in the reactor. The tube was removed on May 31, 1963.

  14. 21 CFR 868.5800 - Tracheostomy tube and tube cuff.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tracheostomy tube and tube cuff. 868.5800 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5800 Tracheostomy tube and tube cuff. (a) Identification. A tracheostomy tube and tube cuff is a device intended to be placed into...

  15. Update on seamless calandria tube development and qualification

    International Nuclear Information System (INIS)

    AECL is undertaking the qualification of the production of seamless calandria tubes as replacement components for installation in reactors during retubing. Seamless tube prototypes made from Zircaloy-2 possessing a suitable crystallographic texture have been shown to be significantly stronger than seam-welded tubes under both rising pressure and sustained pressure conditions in a simulated reactor loading. This paper describes the seamless calandria tube development program and current status. (author)

  16. Internal ultrasonic testing of steam generator tubes

    International Nuclear Information System (INIS)

    The ''in situ'' inspection of steam generator tubes uses generally Foucault currents before starting and along its life. This inspection aims at searching cracks and corrosion defects. The Foucault current method is quite badly adapted to ''closed crack'' detection, for it doesn't introduce neither resistivity or magnetic permeability variation, or lack of matter. More, it is sensible to the magnetic properties of the tube itself and to its environment (tubular or support plates). It is why, this first systematic inspection has to be completed by an ultrasonic one allowing to bring new elements in the uncertain cases. A device with an internal probe has been developed. It ''lights'' the tube wall with the aid of a transducer of which beam reflects on a mirror. Operating conditions are the same as for Foucault current testing, that is to say the probe moves inside the tube without rotation of the device (bent parts are excluded)

  17. Heat exchanger tube tool

    International Nuclear Information System (INIS)

    Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

  18. Automatic Implantable Cardiac Defibrillator

    Medline Plus

    Full Text Available Automatic Implantable Cardiac Defibrillator February 19, 2009 Halifax Health Medical Center, Daytona Beach, FL Welcome to Halifax Health Daytona Beach, Florida. Over the next hour you' ...

  19. Automatic Payroll Deposit System.

    Science.gov (United States)

    Davidson, D. B.

    1979-01-01

    The Automatic Payroll Deposit System in Yakima, Washington's Public School District No. 7, directly transmits each employee's salary amount for each pay period to a bank or other financial institution. (Author/MLF)

  20. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... NEI YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration ... Retinopathy of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia NEI on Twitter NEI on YouTube ...

  1. NEI You Tube Videos: Amblyopia

    Medline Plus

    Full Text Available ... YouTube Videos > NEI YouTube Videos: Amblyopia NEI YouTube Videos YouTube Videos Home Age-Related Macular Degeneration Amblyopia ... of Prematurity Science Spanish Videos Webinars NEI YouTube Videos: Amblyopia NEI on Twitter NEI on YouTube NEI ...

  2. An Empirical Study on the Effect of Output Practice on Chinese EFL Speakers' Automaticity

    Institute of Scientific and Technical Information of China (English)

    杨雅君

    2015-01-01

    The improvement of automaticity in L2 acquisition leads to better fluency and less-consumed attentional resources. In China, current studies on automaticity are mostly theoretical. For a few empirical studies, automaticity in oral production is an issue that has not been explored yet. The significance of automaticity of syntax is manifested in its promotion of accuracy and fluency. Therefore, the author decided to carry out an empirical study to investigate Chinese EFL learners' oral automaticity of grammar.

  3. Automatic Arabic Text Classification

    OpenAIRE

    Al-harbi, S; Almuhareb, A.; Al-Thubaity , A; Khorsheed, M. S.; Al-Rajeh, A.

    2008-01-01

    Automated document classification is an important text mining task especially with the rapid growth of the number of online documents present in Arabic language. Text classification aims to automatically assign the text to a predefined category based on linguistic features. Such a process has different useful applications including, but not restricted to, e-mail spam detection, web page content filtering, and automatic message routing. This paper presents the results of experiments on documen...

  4. Step-and-shoot prospectively ECG-gated vs. retrospectively ECG-gated with tube current modulation coronary CT angiography using 128-slice MDCT patients with chest pain: diagnostic performance and radiation dose

    International Nuclear Information System (INIS)

    Background With increasing awareness for radiation exposure, the study of diagnostic accuracy of coronary CT angiography (CCTA) with low radiation dose techniques is mandatory to both radiologist and clinician. Purpose To compare diagnostic performance and effective radiation dose between step-and-shoot prospectively ECG-gated and retrospectively ECG-gated with tube current modulation (TCM) CCTA using 128-slice multidetector computed tomography (MDCT). Material and Methods We retrospectively evaluated 60 patients who underwent CCTA with either of two different low-dose techniques using 128-slice MDCT (23 patients for step-and shoot-prospectively ECG-gated and 37 patients for retrospectively ECG-gated with TCM CCTA) followed by conventional coronary angiography. All coronary arteries and all segments thereof, except anatomical variants or small size (< 1.5 mm) ones, were included in analysis. Results In per-segment analysis, sensitivity, specificity, positive predictive value, and negative predictive value were 91/96%, 95/94%, 75/73%, and 98/99% for step-and-shoot prospectively ECG-gated and retrospectively ECG gated with TCM CCTA, respectively, relative to conventional coronary angiography. Effective radiation dose were 1.75 ± 0.83 mSv, 4.91 ± 1.71 mSv in the step-and-shoot prospectively ECG-gated and retrospectively ECG-gated with TCM CCTA groups, respectively. Conclusion The two low-radiation dose CCTA techniques using 128-slice MDCT yields comparable diagnostic performance for coronary artery disease in symptomatic patients with low heart rates

  5. Pediatric cuffed endotracheal tubes

    Directory of Open Access Journals (Sweden)

    Neerja Bhardwaj

    2013-01-01

    Full Text Available Endotracheal intubation in children is usually performed utilizing uncuffed endotracheal tubes for conduct of anesthesia as well as for prolonged ventilation in critical care units. However, uncuffed tubes may require multiple changes to avoid excessive air leak, with subsequent environmental pollution making the technique uneconomical. In addition, monitoring of ventilatory parameters, exhaled volumes, and end-expiratory gases may be unreliable. All these problems can be avoided by use of cuffed endotracheal tubes. Besides, cuffed endotracheal tubes may be of advantage in special situations like laparoscopic surgery and in surgical conditions at risk of aspiration. Magnetic resonance imaging (MRI scans in children have found the narrowest portion of larynx at rima glottides. Cuffed endotracheal tubes, therefore, will form a complete seal with low cuff pressure of <15 cm H 2 O without any increase in airway complications. Till recently, the use of cuffed endotracheal tubes was limited by variations in the tube design marketed by different manufacturers. The introduction of a new cuffed endotracheal tube in the market with improved tracheal sealing characteristics may encourage increased safe use of these tubes in clinical practice. A literature search using search words "cuffed endotracheal tube" and "children" from 1980 to January 2012 in PUBMED was conducted. Based on the search, the advantages and potential benefits of cuffed ETT are reviewed in this article.

  6. Failure analysis of retired steam generator tubings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Pyo; Kim, J. S.; Hwang, S. S. and others

    2005-04-15

    Degradation of steam generator leads to forced outage and extension of outage, which causes increase in repair cost, cost of purchasing replacement power and radiation exposure of workers. Steam generator tube rupture incident occurred in Uljin 4 in 2002, which made public sensitive to nuclear power plant. To keep nuclear energy as a main energy source, integrity of steam generator should be demonstrated. Quantitative relationship between ECT(eddy current test) signal and crack size is needed in assesment of integrity of steam generator in pressurized water reactor. However, it is not fully established for application in industry. Retired steam generator of Kori 1 has many kinds of crack such as circumferential and axial primary water stress corrosion crack and outer diameter stress corrosion crack(ODSCC). So, it can be used in qualifying and improving ECT technology and in condition monitoring assesment for crack detected in ISI(in service inspection). In addition, examination of pulled tube of Kori 1 retired steam generator will give information about effectiveness of non welded sleeving technology which was employed to repair defect tubes and remedial action which was applied to mitigate ODSCC. In this project, hardware such as semi hot lab. for pulled tube examination and modification transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. Non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in semi hot lab. Remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. Electrochemical decontamination technology for pulled tube was developed to reduce radiation exposure and enhance effectiveness of pulled tube examination. Multiparameter algorithm developed at ANL, USA was

  7. Failure analysis of retired steam generator tubings

    International Nuclear Information System (INIS)

    Degradation of steam generator leads to forced outage and extension of outage, which causes increase in repair cost, cost of purchasing replacement power and radiation exposure of workers. Steam generator tube rupture incident occurred in Uljin 4 in 2002, which made public sensitive to nuclear power plant. To keep nuclear energy as a main energy source, integrity of steam generator should be demonstrated. Quantitative relationship between ECT(eddy current test) signal and crack size is needed in assesment of integrity of steam generator in pressurized water reactor. However, it is not fully established for application in industry. Retired steam generator of Kori 1 has many kinds of crack such as circumferential and axial primary water stress corrosion crack and outer diameter stress corrosion crack(ODSCC). So, it can be used in qualifying and improving ECT technology and in condition monitoring assesment for crack detected in ISI(in service inspection). In addition, examination of pulled tube of Kori 1 retired steam generator will give information about effectiveness of non welded sleeving technology which was employed to repair defect tubes and remedial action which was applied to mitigate ODSCC. In this project, hardware such as semi hot lab. for pulled tube examination and modification transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. Non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in semi hot lab. Remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. Electrochemical decontamination technology for pulled tube was developed to reduce radiation exposure and enhance effectiveness of pulled tube examination. Multiparameter algorithm developed at ANL, USA was

  8. Microcomputer control soft tube measuring-testing instrument

    Science.gov (United States)

    Zhou, Yanzhou; Jiang, Xiu-Zhen; Wang, Wen-Yi

    1993-09-01

    Soft tube are key and easily spoiled parts used by the vehicles in the transportation with large numbers. Measuring and testing of the tubes were made by hands for a long time. Cooperating with Harbin Railway Bureau recently we have developed a new kind of automatical measuring and testing instrument In the paper the instrument structure property and measuring principle are presented in details. Centre of the system is a singlechip processor INTEL 80C31 . It can collect deal with data and display the results on LED. Furthermore it brings electromagnetic valves and motors under control. Five soft tubes are measured and tested in the same time all the process is finished automatically. On the hardware and software counter-electromagnetic disturbance methods is adopted efficiently so the performance of the instrument is improved significantly. In the long run the instrument is reliable and practical It solves a quite difficult problem in the railway transportation.

  9. Failure Analysis of Retired Steam Generator Tubings

    International Nuclear Information System (INIS)

    Since the first commercial operation of Kori-1 in 1978, 20 units of nuclear power plants are operated, and the it covers 40 % of total electricity in Korea as of 2008. A steam generator tube rupture incident occurred in the Ulchin unit 4 in 2002, which made the public sensitive to nuclear power plant. In order to keep the nuclear energy as a main energy source, the integrity of steam generator should be demonstrated. It is important to improve a flaw detection capability of the eddy current testing(ECT) in steam generator(SG) tubings in order to maintain the tube integrity. A quantified evaluation on the flaws on SG tubings, which is crucial for the tube integrity evaluation is not satisfactory. It is necessary to utilize the retired SG having various types of corrosion damages. In addition, an examination of pulled tube from Kori 1 retired steam generator will give us information about effectiveness of a remedial action(TiO2 addition) which was applied to mitigate ODSCC. A crack growth model is also needed to ensure a tube repair criteria for a next fuel cycle based on the ASME safety evaluation code, which has to meet a requirement that the flaws have to sustain under three times of normal operation pressure difference and 1.4 times of severe accident condition. In this project, hardware such as semi hot lab for pulled tube examination and modification of transportation cask for pulled tube and software such as procedure of transportation of radioactive steam generator tube and non-destructive and destructive examination of pulled tube were established. The non-destructive and destructive examination of pulled tubes from Kori 1 retired steam generator were performed in the semi hot lab. An effect of remedial actions applied to Kori 1 retired steam generator, PWSCC trend and bulk water chemistry and crevice chemistry in Kori 1 were evaluated. An electrochemical decontamination technology for pulled tube was developed to reduce a radiation exposure and enhance

  10. Examination of Trojan steam generator tubes

    International Nuclear Information System (INIS)

    Nondestructive and destructive examinations were performed on sections of ten tubes pulled from Trojan in 1991. Sections of tubing from the 1986 examination were also re-examined. Objectives were to characterize the depths and types of defects present at the tube support plate intersections (TSPs), determine the burst pressure of the TSPs, determine the ability of various field eddy current test techniques to characterize the defects, characterize any defects occurring near the top of the tubesheet and to characterize deposits on the OD of the tube. The TSPs had burst pressures in excess of the NRC requirement of 3 times normal operating primary to secondary water pressure differential. The defects, found at all TSPs examined, were a series of tight OD initiated, axially orientated intergranular stress corrosion cracks (IGSCC), bound by the crevice formed between the tube and the support plate. One tube had defects that were a mixture of intergranular attack and IGSCC. Eddy current techniques were found to be an effective method of assessing tube integrity. Maximum penetration in each TSP was 49 to 98% throughwall. Cracking was attributed to caustic in crevices. No defects were found outside the TSP crevice. Deposits, composed primarily of magnetite and copper, had far lower levels of chloride and sulfate than in 1986

  11. Reducing radiation dose to the female breast during CT coronary angiography: A simulation study comparing breast shielding, angular tube current modulation, reduced kV, and partial angle protocols using an unknown-location signal-detectability metric

    International Nuclear Information System (INIS)

    Purpose: The authors compared the performance of five protocols intended to reduce dose to the breast during computed tomography (CT) coronary angiography scans using a model observer unknown-location signal-detectability metric.Methods: The authors simulated CT images of an anthropomorphic female thorax phantom for a 120 kV reference protocol and five “dose reduction” protocols intended to reduce dose to the breast: 120 kV partial angle (posteriorly centered), 120 kV tube-current modulated (TCM), 120 kV with shielded breasts, 80 kV, and 80 kV partial angle (posteriorly centered). Two image quality tasks were investigated: the detection and localization of 4-mm, 3.25 mg/ml and 1-mm, 6.0 mg/ml iodine contrast signals randomly located in the heart region. For each protocol, the authors plotted the signal detectability, as quantified by the area under the exponentially transformed free response characteristic curve estimator (A-caretFE), as well as noise and contrast-to-noise ratio (CNR) versus breast and lung dose. In addition, the authors quantified each protocol's dose performance as the percent difference in dose relative to the reference protocol achieved while maintaining equivalent A-caretFE.Results: For the 4-mm signal-size task, the 80 kV full scan and 80 kV partial angle protocols decreased dose to the breast (80.5% and 85.3%, respectively) and lung (80.5% and 76.7%, respectively) with A-caretFE = 0.96, but also resulted in an approximate three-fold increase in image noise. The 120 kV partial protocol reduced dose to the breast (17.6%) at the expense of increased lung dose (25.3%). The TCM algorithm decreased dose to the breast (6.0%) and lung (10.4%). Breast shielding increased breast dose (67.8%) and lung dose (103.4%). The 80 kV and 80 kV partial protocols demonstrated greater dose reductions for the 4-mm task than for the 1-mm task, and the shielded protocol showed a larger increase in dose for the 4-mm task than for the 1-mm task. In general, the

  12. Conduction cooled tube supports

    Science.gov (United States)

    Worley, Arthur C.; Becht, IV, Charles

    1984-01-01

    In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

  13. Tubing weld cracking test

    International Nuclear Information System (INIS)

    A tubing weld cracking (TWC) test was developed for applications involving advanced austenitic alloys (such as modified 800H and 310HCbN). Compared to the Finger hot cracking test, the TWC test shows an enhanced ability to evaluate the crack sensitivity of tubing materials. The TWC test can evaluate the cracking tendency of base as well as filter materials. Thus, it is a useful tool for tubing suppliers, filler metal producers and fabricators

  14. X-ray tubes study and design

    International Nuclear Information System (INIS)

    This thesis contain both theoretical and experimental works. Theoretical aspect includes X-Ray tubes case study and design principles, in the introduced design process, anode-cathode distance, vacuum needed, filament size, anode face angle and shape and size of focusing electrodes can be found. A method for specification of tungsten lager thickness on anode is also introduced. Using computer simulation, electron trajectory between cathode-anode is obtained, This work is presented in the first International Conference on Control and Modeling, Tehran, 1990. Experimental work contains manufacturing more than 10 tubes and test each of them. One of these tubes can with stand up to 50 KV. Filament can be heated by passing a 2.1 A current. In these conditions anode current is 1.2 m A. Using this tube, some radiographs have been taken

  15. Cyclotron resonance in a cathode ray tube

    International Nuclear Information System (INIS)

    Absorption of the RF energy by the electron beam in a cathode ray tube due to the cyclotron resonance is described. The cathode ray tube is placed within a Helmholtz coils system supplied by a sawtooth current generator. In order to generate RF field and to detect RF absorption a gate dip-meter equipped with a FET transistor is used. The bias voltage variations of the FET transistors as a function of the magnetic field are recorded. The operating point of the cathode ray tube has been chosen so that the relaxation oscillations of the detection system can be observed. (authors)

  16. Establishment of a semi-biological phantom model for the study of the effect of dose reducing measures on radiation-induced DNA double strand breaks in CT using the example of risk organ based tube current modulation; Etablierung eines semibiologischen Phantommodells zur Untersuchung des Effekts dosisreduzierender Massnahmen auf strahleninduzierte DNA-Doppelstrangbrueche in der CT am Beispiel der risikoorganbasierten Roehrenstrommodulation

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Matthias

    2013-12-12

    The number of computed tomography (CT) examinations has been rising during the last decades. Therefore techniques for dose reduction receive increasing attention. Risk organ-based tube current modulation (RCM) in CT is a new approach and works by lowering the tube current, while the tube is in front of the patient's body. Therefore it should lead to a dose reduction for radiosensitive organs like the female breast, the eye lenses and the thyroid gland. Biological radiation effects cannot be estimated by physical-based dose measurements. γ-H2AX is a sensitive marker for the determination of x-ray induced DNA double-strand breaks (DSB). Hence the aim of this study was to establish a biological phantom model based on the γ-H2AX immunofluorescence microscopy method and to investigate the effect of RCM on radiation induced DNA damages. The γ-H2AX method is based on the phosphorylation of the histone variant H2AX. The phosphorylated histone γ-H2AX can be visualised using antibodies and is specific for radiation induced DSB. Blood lymphocytes from healthy volunteers, skin fibroblasts (LN) and mammary epithelial cells (HMEpC-p) were placed in different positions of an Alderson-phantom and exposed to x-rays using a 128-slice dual-source CT scanner. Standard head, neck and chest-CT scan protocols either with or without risk-organ based tube current modulation were used. RCM reduces the tube current to 20 percent at an angle of 130 degree anterior to the body, whereas tube current is increased at an angle of 230 degree posterior to the body. Afterwards cells were isolated, fixed on slides und stained with specific primary γ-H2AX antibodies and fluorescent secondary antibodies. Tiny green dots (named foci) can be detected and quantified with a fluorescence microscope and represent distinct DSB. Non-irradiated samples served as controls and CT-induced DSB were calculated by subtraction of pre- from post-exposure values. In this study a semibiological phantom model

  17. Categorising YouTube

    OpenAIRE

    Thomas Mosebo Simonsen

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a...

  18. Calibrations of photomultiplier tubes

    International Nuclear Information System (INIS)

    The experimental methods for calibration photomultiplier tubes used in the multichannel fast-pulse-detection system of Thomson scattering measurements for nuclear fusion devices is reported. The most important parameters of the photomultiplier tubes to be calibrated include: linearity of output electric signals to input light signals, response time of pulsed light, spectral response, absolute responsibility, and sensitivity as a function of the chain voltage. The calibrations of all these parameters are carried out by using EMI 9558 B and RCA 7265 photomultiplier tubes respectively. The experimental methods presented in the paper are common to those quantitative measurements that require phomultiplier tubes as detectors

  19. Composite Pulse Tube

    Science.gov (United States)

    Martin, Jerry L.; Cloyd, Jason H.

    2007-01-01

    A modification of the design of the pulse tube in a pulse-tube cryocooler reduces axial thermal conductance while preserving radial thermal conductance. It is desirable to minimize axial thermal conductance in the pulse-tube wall to minimize leakage of heat between the warm and cold ends of the pulse tube. At the same time, it is desirable to maximize radial thermal conductance at the cold end of the pulse tube to ensure adequate thermal contact between (1) a heat exchanger in the form of a stack of copper screens inside the pulse tube at the cold end and (2) the remainder of the cold tip, which is the object to which the heat load is applied and from which heat must be removed. The modified design yields a low-heat-leak pulse tube that can be easily integrated with a cold tip. A typical pulse tube of prior design is either a thin-walled metal tube or a metal tube with a nonmetallic lining. It is desirable that the outer surface of a pulse tube be cylindrical (in contradistinction to tapered) to simplify the design of a regenerator that is also part of the cryocooler. Under some conditions, it is desirable to taper the inner surface of the pulse tube to reduce acoustic streaming. The combination of a cylindrical outer surface and a tapered inner surface can lead to unacceptably large axial conduction if the pulse tube is made entirely of metal. Making the pulse-tube wall of a nonmetallic, lowthermal- conductivity material would not solve the problem because the wall would not afford the needed thermal contact for the stack of screens in the cold end. The modified design calls for fabricating the pulse tube in two parts: a longer, nonmetallic part that is tapered on the inside and cylindrical on the outside and a shorter, metallic part that is cylindrical on both the inside and the outside. The nonmetallic part can be made from G-10 fiberglass-reinforced epoxy or other low-thermal-conductivity, cryogenically compatible material. The metallic part must have high

  20. Manual tube welding torch

    International Nuclear Information System (INIS)

    In a welding torch which fits over a tube intermediate the ends thereof for welding the juncture between the tube and a boss on the back side of a tube plate, a split housing encloses a tungsten electrode, a filler wire duct and a fiber optic bundle arranged to observe the welding process. A shielding gas duct is provided in the housing. A screw is provided for setting electrode/work distance. Difficult remote tube welding operations can be performed with the apparatus. (author)

  1. Steam generator tube performance

    International Nuclear Information System (INIS)

    A survey of steam generator operating experience for 1986 has been carried out for 184 pressurized water and pressurized heavy-water reactors, and 1 water-cooled, graphite-moderated reactor. Tubes were plugged at 75 of the reactors (40.5%). In 1986, 3737 tubes were plugged (0.14% of those in service) and 3148 tubes were repaired by sleeving. A small number of reactors accounted for the bulk of the plugged tubes, a phenomenon consistent with previous years. For 1986, the available tubesheet sludge data for 38 reactors has been compiled into tabular form, and sludge/deposit data will be incorporated into all future surveys

  2. Effective string description of confining flux tubes

    CERN Document Server

    Brandt, Bastian B

    2016-01-01

    We review the current knowledge about the theoretical foundations of the effective string theory for confining flux tubes and the comparison of the predictions to pure gauge lattice data. A concise presentation of the effective string theory is provided, incorporating recent developments. We summarize the predictions for the spectrum and the profile/width of the flux tube and their comparison to lattice data. The review closes with a short summary of open questions for future research.

  3. Effective string description of confining flux tubes

    Science.gov (United States)

    Brandt, Bastian B.; Meineri, Marco

    2016-08-01

    We review the current knowledge about the theoretical foundations of the effective string theory for confining flux tubes and the comparison of the predictions to pure gauge lattice data. A concise presentation of the effective string theory is provided, incorporating recent developments. We summarize the predictions for the spectrum and the profile/width of the flux tube and their comparison to lattice data. The review closes with a short summary of open questions for future research.

  4. A Position Estimation Method of the Control Rod Guide Tube with Matched Filters

    International Nuclear Information System (INIS)

    The risk that PWR guide tube support pins will crack has increased the necessity for the development of inspection methods and equipment. A special remote controlled manipulator has been widely used to inspect the guide tube support pins. In real situations, the manipulator is lowered into the internals pool and all the movements are monitored and controlled from a desk at the side of the pool. Because the diameter of the split pins is as small as 25mm, locating the ultrasonic transducer to the pins by a manual operation is a somewhat tedious task. To overcome this problem, a rail was placed on the bottom of the pool before the internals of the reactor vessel were lifted and lowered on to their stand. In this paper, we presented one method to eliminate this troublesome job by using a vision sensor already being used to monitor the manipulator's movements. There were some successful researches in designing controls for many dynamic systems in the case of their current position and where the desired trajectories are well defined. But a current position estimation of a robot and/or environmental objects is another problem that must be solved. A Matched filter algorithm is employed as a method for an automatic detection of the guide tube's and support pin's relative position to that of the robot. First, we construct two raw images corresponding to the guide tube and the support pin respectively. These are simply binary-valued image files that contain the shapes of each object. Next, we performed a 2-D FFT(fast fourier transform) on them. The transformed data files are the matched-filters to detect the presence of a guide tube and/or support pins and to estimate the positions of them. The cross correlation between the matched-filter and real input image can be calculated by the method of multiplying them followed by an inverse FFT. If the resulting value is greater than the pre-determined threshold value, we can conclude that there is at least one object which we are

  5. Steam generator tube failures

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  6. Steam generator tube failures

    International Nuclear Information System (INIS)

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  7. Automatic Program Development

    DEFF Research Database (Denmark)

    Automatic Program Development is a tribute to Robert Paige (1947-1999), our accomplished and respected colleague, and moreover our good friend, whose untimely passing was a loss to our academic and research community. We have collected the revised, updated versions of the papers published in his...... honor in the Higher-Order and Symbolic Computation Journal in the years 2003 and 2005. Among them there are two papers by Bob: (i) a retrospective view of his research lines, and (ii) a proposal for future studies in the area of the automatic program derivation. The book also includes some papers by...... members of the IFIP Working Group 2.1 of which Bob was an active member. All papers are related to some of the research interests of Bob and, in particular, to the transformational development of programs and their algorithmic derivation from formal specifications. Automatic Program Development offers a...

  8. Effect of shot peening on steam generator tube cracking risks

    International Nuclear Information System (INIS)

    One of the main SG tube degradation modes in stress corrosion cracking on the primary side in the tube/tube plate roll transition zone. With a view to mitigating these cracking risks, on the 900 MWe PWR's plant, the SG inner tube walls were mechanically stress-relieved by shot peening. Between 1985 and 1988, periodic eddy current testing were performed during refuelling outages before and after the shot peening that allows to monitor the number and condition of affected tubes versus time in service. Statistical analysis were performed in order to test and quantify the effects of this treatment. (author). 3 figs., 2 refs

  9. Step-and-shoot prospectively ECG-gated versus retrospectively ECG-gated with tube current modulation coronary CT angiography using the 128-slice MDCT: comparison of image quality and radiation dose

    International Nuclear Information System (INIS)

    Background: Little is known regarding image quality and the required radiation dose for step-and-shoot and retrospective coronary computed tomography angiography (CCTA) with tube current modulation (TCM) in 128-slice multidetector CT (MDCT) coronary angiography. Purpose: To compare image quality and radiation dose in patients who underwent 128-slice MDCT by the step-and- shoot method with those in patients who underwent 128-slice MDCT with retrospective CCTA with TCM. Material and Methods: CCTA obtained with 128-slice MDCT was retrospectively evaluated in 160 patients. Two independent reviewers separately scored the subjective image quality of the coronary artery segments (1, excellent; 4, poor) for step-and-shoot (68, mean heart rate [HR]: 59.3±6.8) and retrospective CCTA with TCM (77, mean HR: 59.1±9.8). Interobserver variability was calculated. Effective radiation doses of both scan techniques were calculated with dose-length product. Results: There was good agreement for quality scores of coronary artery segment images between the independent reviewers (k=0.72). The number of coronary artery segments that could not be evaluated was 2.85% (27 of 947) in the step-and-shoot and 1.87% (20 of 1071) in retrospective CCTA with TCM. Image quality scores were not significantly different (P>.05). Mean patient radiation dose was 63% lower for step-and-shoot (1.94±0.70 mSv) than for retrospective CCTA with TCM (4.51±1.18 mSv) (P<0.0001). For patients who underwent step-and-shoot or retrospective CCTA with TCM, an average HR of 63.5 beats per minute was identified as the threshold for the prediction of non-diagnostic image quality for both protocols. There were no significant differences in the image quality of both methods between obese (body mass index [BMI≥25) and non-obese patients (BMI<25), but radiation doses were higher in the obesity group than in the non-obesity group for both methods. Conclusion: Both step-and-shoot and retrospective CCTA with TCM using 128

  10. Step-and-shoot prospectively ECG-gated versus retrospectively ECG-gated with tube current modulation coronary CT angiography using the 128-slice MDCT: comparison of image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Dong Wook (Dept. of Family Medicine, Medial Research Institute, Pusan National Univ. Yangsan Hospital, School of Medicine, Gyeongsangnam-do, (Korea, Republic of)); Choo, Ki Seok; Baik, Seung Kug; Kim, Yong Woo; Jeon, Ung Bae (Dept. of Radiology, Medial Research Institute, Pusan National Univ. Yangsan Hospital, School of Medicine, Gyeongsangnam-do, (Korea, Republic of)), email: kschoo0618@naver.com; Kim, Jeong Soo (Dept. of Cardiology, Medial Research Institute, Pusan National Univ. Yangsan Hospital, School of Medicine, Gyeongsangnam-do (Korea, Republic of)); Lim, Soo Jin (Dept. of Cardiology, Kim Hae Joongang Hospital, Gyeongsangnam-do (Korea, Republic of))

    2011-02-15

    Background: Little is known regarding image quality and the required radiation dose for step-and-shoot and retrospective coronary computed tomography angiography (CCTA) with tube current modulation (TCM) in 128-slice multidetector CT (MDCT) coronary angiography. Purpose: To compare image quality and radiation dose in patients who underwent 128-slice MDCT by the step-and- shoot method with those in patients who underwent 128-slice MDCT with retrospective CCTA with TCM. Material and Methods: CCTA obtained with 128-slice MDCT was retrospectively evaluated in 160 patients. Two independent reviewers separately scored the subjective image quality of the coronary artery segments (1, excellent; 4, poor) for step-and-shoot (68, mean heart rate [HR]: 59.3+-6.8) and retrospective CCTA with TCM (77, mean HR: 59.1+-9.8). Interobserver variability was calculated. Effective radiation doses of both scan techniques were calculated with dose-length product. Results: There was good agreement for quality scores of coronary artery segment images between the independent reviewers (k=0.72). The number of coronary artery segments that could not be evaluated was 2.85% (27 of 947) in the step-and-shoot and 1.87% (20 of 1071) in retrospective CCTA with TCM. Image quality scores were not significantly different (P>.05). Mean patient radiation dose was 63% lower for step-and-shoot (1.94+-0.70 mSv) than for retrospective CCTA with TCM (4.51+-1.18 mSv) (P<0.0001). For patients who underwent step-and-shoot or retrospective CCTA with TCM, an average HR of 63.5 beats per minute was identified as the threshold for the prediction of non-diagnostic image quality for both protocols. There were no significant differences in the image quality of both methods between obese (body mass index [BMI>=25) and non-obese patients (BMI<25), but radiation doses were higher in the obesity group than in the non-obesity group for both methods. Conclusion: Both step-and-shoot and retrospective CCTA with TCM using 128

  11. Neuroanatomical automatic segmentation in brain cancer patients

    OpenAIRE

    D’Haese, P.; Niermann, K; Cmelak, A.; Donnelly, E.; Duay, V.; Li, R; Dawant, B.

    2003-01-01

    Conformally prescribed radiation therapy for brain cancer requires precisely defining the target treatment area, as well as delineating vital brain structures which must be spared from radiotoxicity. The current clinical practice of manually segmenting brain structures can be complex and exceedingly time consuming. Automatic computeraided segmentation methods have been proposed to increase efficiency and reproducibility in developing radiation treatment plans. Previous studies have establishe...

  12. Portable machine welding head automatically controls arc

    Science.gov (United States)

    Oleksiak, C. E.; Robb, M. A.

    1967-01-01

    Portable weld tool makes weld repairs out-of-station and on the side opposite the original weld. It provides full automatic control of the arc voltage, current, wire feed, and electrode travel speed in all welding attitudes. The device is readily adaptable to commercially available straight polarity dc weld packs.

  13. Handwriting Automaticity: The Search for Performance Thresholds

    Science.gov (United States)

    Medwell, Jane; Wray, David

    2014-01-01

    Evidence is accumulating that handwriting has an important role in written composition. In particular, handwriting automaticity appears to relate to success in composition. This relationship has been little explored in British contexts and we currently have little idea of what threshold performance levels might be. In this paper, we report on two…

  14. Automatic utilities auditing

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Colin Boughton [Energy Metering Technology (United Kingdom)

    2000-08-01

    At present, energy audits represent only snapshot situations of the flow of energy. The normal pattern of energy audits as seen through the eyes of an experienced energy auditor is described. A brief history of energy auditing is given. It is claimed that the future of energy auditing lies in automatic meter reading with expert data analysis providing continuous automatic auditing thereby reducing the skill element. Ultimately, it will be feasible to carry out auditing at intervals of say 30 minutes rather than five years.

  15. Automatic Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Preuss, Mike

    2014-01-01

    Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...... camera. We approach this problem by modelling it as a dynamic multi-objective optimisation problem and show how this metaphor allows a much richer expressiveness than a classical single objective approach. Finally, we showcase the application of a multi-objective evolutionary algorithm to generate a shot...

  16. Techniques for automatic speech recognition

    Science.gov (United States)

    Moore, R. K.

    1983-05-01

    A brief insight into some of the algorithms that lie behind current automatic speech recognition system is provided. Early phonetically based approaches were not particularly successful, due mainly to a lack of appreciation of the problems involved. These problems are summarized, and various recognition techniques are reviewed in the contect of the solutions that they provide. It is pointed out that the majority of currently available speech recognition equipments employ a "whole-word' pattern matching approach which, although relatively simple, has proved particularly successful in its ability to recognize speech. The concepts of time-normalizing plays a central role in this type of recognition process and a family of such algorithms is described in detail. The technique of dynamic time warping is not only capable of providing good performance for isolated word recognition, but how it is also extended to the recognition of connected speech (thereby removing one of the most severe limitations of early speech recognition equipment).

  17. Eddy current testing

    Energy Technology Data Exchange (ETDEWEB)

    Song, Sung Jin; Lee, Hyang Beom; Kim, Young Hwan [Soongsil Univ., Seoul (Korea, Republic of); Shin, Young Kil [Kunsan Univ., Gunsan (Korea, Republic of)

    2004-02-15

    Eddy current testing has been widely used for non destructive testing of steam generator tubes. In order to retain reliability in ECT, the following subjects were carried out in this study: numerical modeling and analysis of defects by using BC and RPC probes in SG tube, preparation of absolute coil impedance plane diagram by FEM. Signal interpretation of the eddy current signals obtained from nuclear power plants.

  18. Pyrotechnic Tubing Connector

    Science.gov (United States)

    Graves, Thomas J.; Yang, Robert A.

    1988-01-01

    Tool forms mechanical seal at joint without levers or hydraulic apparatus. Proposed tool intended for use in outer space used on Earth by heavily garbed workers to join tubing in difficult environments. Called Pyrotool, used with Lokring (or equivalent) fittings. Piston slides in cylinder when pushed by gas from detonating pyrotechnic charge. Impulse of piston compresses fittings, sealing around butting ends of tubes.

  19. Welding Tubes In Place

    Science.gov (United States)

    Meredith, R.

    1984-01-01

    Special welding equipment joins metal tubes that carry pressurized cyrogenic fluids. Equipment small enough to be used in confined spaces in which such tubes often mounted. Welded joints lighter in weight and more leak-proof than joints made with mechanical fittings.

  20. A semi-automatic TLD personnel monitoring badge processor for routine use

    International Nuclear Information System (INIS)

    A semi-automatic TLD reader developed for large scale processing of personnel monitoring badges is described. The badge is made of three CaSO4 : Dy - teflon disc dosimeters. The light output obtained by heating the phosphor discs is measured by a PM tube, from which the output current is converted to pulse rate and fed into a 6 digit Nixie display thereby enabling dose measurements over a wide range. An autoranging count rate meter provides the glow curve output for external recording. The unit utilizes integrated circuits throughout for reliable performance. The instrument fulfils a long-standing need for large scale processing of TLD badges required for personnel monitoring. (author)

  1. Categorising YouTube

    DEFF Research Database (Denmark)

    Simonsen, Thomas Mosebo

    2011-01-01

    This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC) of YouTube. The article investigates the construction of navigation processes on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s...... technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition...... and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC...

  2. Automatic malware analysis an emulator based approach

    CERN Document Server

    Yin, Heng

    2012-01-01

    Malicious software (i.e., malware) has become a severe threat to interconnected computer systems for decades and has caused billions of dollars damages each year. A large volume of new malware samples are discovered daily. Even worse, malware is rapidly evolving becoming more sophisticated and evasive to strike against current malware analysis and defense systems. Automatic Malware Analysis presents a virtualized malware analysis framework that addresses common challenges in malware analysis. In regards to this new analysis framework, a series of analysis techniques for automatic malware analy

  3. Automatic and strategic processes in advertising effects

    DEFF Research Database (Denmark)

    Grunert, Klaus G.

    1996-01-01

    , and can easily be adapted to situational circumstances. Both the perception of advertising and the way advertising influences brand evaluation involves both processes. Automatic processes govern the recognition of advertising stimuli, the relevance decision which determines further higher-level processing...... are at variance with current notions about advertising effects. For example, the att span problem will be relevant only for strategic processes, not for automatic processes, a certain amount of learning can occur with very little conscious effort, and advertising's effect on brand evaluation may be more stable...

  4. Unification of automatic target tracking and automatic target recognition

    Science.gov (United States)

    Schachter, Bruce J.

    2014-06-01

    The subject being addressed is how an automatic target tracker (ATT) and an automatic target recognizer (ATR) can be fused together so tightly and so well that their distinctiveness becomes lost in the merger. This has historically not been the case outside of biology and a few academic papers. The biological model of ATT∪ATR arises from dynamic patterns of activity distributed across many neural circuits and structures (including retina). The information that the brain receives from the eyes is "old news" at the time that it receives it. The eyes and brain forecast a tracked object's future position, rather than relying on received retinal position. Anticipation of the next moment - building up a consistent perception - is accomplished under difficult conditions: motion (eyes, head, body, scene background, target) and processing limitations (neural noise, delays, eye jitter, distractions). Not only does the human vision system surmount these problems, but it has innate mechanisms to exploit motion in support of target detection and classification. Biological vision doesn't normally operate on snapshots. Feature extraction, detection and recognition are spatiotemporal. When vision is viewed as a spatiotemporal process, target detection, recognition, tracking, event detection and activity recognition, do not seem as distinct as they are in current ATT and ATR designs. They appear as similar mechanism taking place at varying time scales. A framework is provided for unifying ATT and ATR.

  5. Sensor-actuator coupled device for active tracheal tube using solid polymer electrolyte membrane

    Science.gov (United States)

    Ihara, Tadashi; Nakamura, Taro; Mukai, Toshiharu; Asaka, Kinji

    2007-04-01

    A sensor-actuator coupled device was developed using solid polymer electrolyte membrane (SPM) as an active tracheal tube for ventilator. Active tracheal tube is a novel type of tube for ventilator that removes patient's phlegm automatically upon sensing the narrowing of trachea by phlegm. This type of active tube is extremely useful in clinical settings as currently the sole measure to remove phlegm from patient's tube is to do it manually by a nurse every few hours. As SPM works both as a sensor and an actuator, an effective compact device was developed. SPM based sensor-actuator coupled device was fabricated with modified gold plating method. Prepared SPM was fixed as an array on a plastic pipe of diameter 22 mm and was connected to a ventilator circuit and driven by a ventilator with a volume control ventilation (VCV) mode. SPM was connected both to a sensing unit and an actuation unit. Generated voltage developed by the membrane with the setting of the maximum pressure from 5 cmH IIO to 20 cmH IIO was in order of several hundred μV. SPM sensor demonstrated a biphasic response to the ventilator flow. The sensor data showed nearly linearly proportional voltage development to the intra-tracheal pressure. The sensed signal was filtered and digitized with an A/D converting unit on a PC board. A real time operating program was used to detect the sensed signal that indicates the narrowing of trachea. The program then activated a driving signal to control the actuation of the membrane. The signal was sent to a D/A converting unit. The output of the D/A unit was sent to an amplifier and the galvanostat unit which drives the membrane with constant current regardless of the change in the load. It was demonstrated that the sensor-actuator unit detects the narrowing of trachea within several hundreds milli-seconds and responds by actuating the same membrane with the driving voltage of 3-4 V and driving current of several hundred milli-ampere for each membrane. SPM array

  6. Automatic Dance Lesson Generation

    Science.gov (United States)

    Yang, Yang; Leung, H.; Yue, Lihua; Deng, LiQun

    2012-01-01

    In this paper, an automatic lesson generation system is presented which is suitable in a learning-by-mimicking scenario where the learning objects can be represented as multiattribute time series data. The dance is used as an example in this paper to illustrate the idea. Given a dance motion sequence as the input, the proposed lesson generation…

  7. Automatic Complexity Analysis

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    1989-01-01

    One way to analyse programs is to to derive expressions for their computational behaviour. A time bound function (or worst-case complexity) gives an upper bound for the computation time as a function of the size of input. We describe a system to derive such time bounds automatically using abstract...

  8. Sleeving repair of heat exchanger tubes

    International Nuclear Information System (INIS)

    Defective heat exchanger tubes can be repaired using techniques that do not involve the cost and schedule penalties of component replacement. FTI's years of experience repairing steam generator tubes have been successfully applied to heat exchangers. Framatome Technologies heat exchanger sleeves can bridge defective areas of the heat exchanger tubes, sleeves have been designed to repair typical heat exchanger tube defects caused by excessive tube vibration, stress corrosion cracking, pitting or erosion. By installing a sleeve, the majority of the tube's heat transfer and flow capacity is maintained and the need to replace the heat exchanger can be delayed or eliminated. Both performance and reliability are improved. FTI typically installs heat exchanger tube sleeves using either a roll expansion or hydraulic expansion process. While roll expansion of a sleeve can be accomplished very quickly, hydraulic expansion allows sleeves to be installed deep within a tube where a roll expander cannot reach. Benefits of FTI's heat exchanger tube sleeving techniques include: - Sleeves can be positioned any where along the tube length, and for precise positioning of the sleeve eddy current techniques can be employed. - Varying sleeve lengths can be used. - Both the roll and hydraulic expansion processes are rapid and both produce joints that do not require stress relief. - Because of low leak rates and speed of installations, sleeves can be used to preventatively repair likely-to-fail tubes. - Sleeves can be used for tube stiffening and to limit leakage through tube defects. - Because of installation speed, there is minimal impact on outage schedules and budgets. FTI's recently installed heat exchanger sleeving at the Kori-3 Nuclear Power Station in conjunction with Korea Plant Service and Engineering Co., Ltd. The sleeves were installed in the 3A and 3B component cooling water heat exchangers. A total of 859 tubesheet and 68 freespan sleeves were installed in the 3A heat

  9. Fault injection system for automatic testing system

    Institute of Scientific and Technical Information of China (English)

    王胜文; 洪炳熔

    2003-01-01

    Considering the deficiency of the means for confirming the attribution of fault redundancy in the re-search of Automatic Testing System(ATS) , a fault-injection system has been proposed to study fault redundancyof automatic testing system through compurison. By means of a fault-imbeded environmental simulation, thefaults injected at the input level of the software are under test. These faults may induce inherent failure mode,thus bringing about unexpected output, and the anticipated goal of the test is attained. The fault injection con-sists of voltage signal generator, current signal generator and rear drive circuit which are specially developed,and the ATS can work regularly by means of software simulation. The experimental results indicate that the faultinjection system can find the deficiency of the automatic testing software, and identify the preference of fault re-dundancy. On the other hand, some soft deficiency never exposed before can be identified by analyzing the tes-ting results.

  10. AUTOMATIC WEB SCRAPPING USING VISUAL SELECTORS

    Directory of Open Access Journals (Sweden)

    Rashmi Bhosale

    2015-12-01

    Full Text Available The amount of information that is currently vailable on the net grows at a very fast pace, thus web can be considered as the largest knowledge repository ever developed and made available to the public. A web data extraction system is a system that extracts data from web pages automatically. Web data analysis applications such as extracting mutual funds information from a website, extracting opening and closing price of stock daily from a web page and so on involves web data extraction.Early techniques were construcingt wrapper to visit those sites and collect data which is time consuming. Thus a technique called as Automatic Web Scrapping Using Visual Selectors(AWSUVS is proposed. For selected data sections AWSUVS discovers extraction pattern automatically. AWSUVS uses visual cues to identify data records while ignoring noise items such as advertises and navigation bars.

  11. Pressure tube type reactor

    International Nuclear Information System (INIS)

    Heretofore, a pressure tube type reactor has a problem in that the evaluation for the reactor core performance is complicate and no sufficient consideration is made for the economical property, to increase the size of a calandria tank and make the cost expensive. Then, in the present invention, the inner diameter of a pressure tube is set to greater than 50% of the lattice gap in a square lattice like arrangement, and the difference between the inner and the outer diameters of the calandria tube is set smaller than 20% of the lattice gap. Further, the inner diameter of the pressure tube is set to greater than 40% and the difference between the inner and the outer diameters of the calandria tube is set smaller than 30% of the lattice gap in a triangle lattice arrangement. Then, heavy water-to-fuel volume ratio can be determined appropriately and the value for the coolant void coefficient is made more negative side, to improve the self controllability inherent to the reactor. In particular, when 72 to 90 fuel rods are arranged per one pressure tube, the power density per one fuel rod is can be increased by about twice. Accordingly, the number of the pressure tubes can be reduced about to one-half, thereby enabling to remarkably decrease the diameter of the reactor core and to reduce the size of the calandria, which is economical. (N.H.)

  12. The Choking Game on YouTube

    Science.gov (United States)

    Defenderfer, Ellen K.; Austin, Jillian E.; Davies, W. Hobart

    2016-01-01

    The choking game (TCG) is an adolescent activity in which asphyxiation is used to obtain a “high,” occasionally resulting in seizures or death. A plethora of TCG information is available through YouTube, though this content has not been evaluated recently. The current study described TCG as portrayed in YouTube videos and compared views and ratings of TCG videos to unrelated videos. The TCG videos demonstrated diverse methods of asphyxiation, with a minority showing injury to the participants. TCG videos were less likely to be commented on or rated positively than non–choking game videos. TCG prevention videos differed significantly from actual TCG videos in the way they depicted the social context of TCG. Thus, TCG videos are accessible through YouTube, but the prevention materials available on YouTube are not accurate or representative. Accurate and educational online prevention materials should be created to decrease the occurrence of TCG. PMID:27335992

  13. Automatic indexing, compiling and classification

    International Nuclear Information System (INIS)

    A review of the principles of automatic indexing, is followed by a comparison and summing-up of work by the authors and by a Soviet staff from the Moscou INFORM-ELECTRO Institute. The mathematical and linguistic problems of the automatic building of thesaurus and automatic classification are examined

  14. Magnetic flux tube tunneling

    International Nuclear Information System (INIS)

    We present numerical simulations of the collision and subsequent interaction of orthogonal magnetic flux tubes. The simulations were carried out using a parallelized spectral algorithm for compressible magnetohydrodynamics. It is found that, under a wide range of conditions, the flux tubes can open-quotes tunnelclose quotes through each other, a behavior not previously seen in studies of either vortex tube or magnetic flux tube interactions. Two conditions must be satisfied for tunneling to occur: the magnetic field must be highly twisted with a field line pitch >1, and the Lundquist number must be somewhat large, ≥2880. An examination of magnetic field lines suggests that tunneling is due to a double-reconnection mechanism. Initially orthogonal field lines reconnect at two specific locations, exchange interacting sections, and open-quotes passclose quotes through each other. The implications of these results for solar and space plasmas are discussed. copyright 1997 The American Physical Society

  15. Integrated structure vacuum tube

    Science.gov (United States)

    Dimeff, J.; Kerwin, W. J. (Inventor)

    1976-01-01

    High efficiency, multi-dimensional thin film vacuum tubes suitable for use in high temperature, high radiation environments are described. The tubes are fabricated by placing thin film electrode members in selected arrays on facing interior wall surfaces of an alumina substrate envelope. Cathode members are formed using thin films of triple carbonate. The photoresist used in photolithography aids in activation of the cathodes by carbonizing and reacting with the reduced carbonates when heated in vacuum during forming. The finely powdered triple carbonate is mixed with the photoresist used to delineate the cathode locations in the conventional solid state photolithographic manner. Anode and grid members are formed using thin films of refractory metal. Electron flow in the tubes is between grid elements from cathode to anode as in a conventional three-dimensional tube.

  16. Automatic ion extraction from high-frequency ion source

    International Nuclear Information System (INIS)

    A description and results of tests of device for automatic extraction of ions from a high-frequency ion source are presented. The automatic regime is realized by introducing feedback with respect to the current of the source cathode and requires low sinusoidal modulation of the exctracting voltage. By varying the power of the discharge the beam current was controlled in the 90-1470μA range with automatic preservation of the optimal conditions in the extraction system. The device was used on a 210-kV neutron generator

  17. The automatic NMR gaussmeter

    International Nuclear Information System (INIS)

    The paper describes the automatic gaussmeter operating according to the principle of nuclear magnetic resonance. There have been discussed the operating principle, the block diagram and operating parameters of the meter. It can be applied to measurements of induction in electromagnets of wide-line radio-spectrometers EPR and NMR and in calibration stands of magnetic induction values. Frequency range of an autodyne oscillator from 0,6 up to 86 MHz for protons is corresponding to the field range from 0.016 up to 2T. Applicaton of other nuclei, such as 7Li and 2D is also foreseen. The induction measurement is carried over automatically, and the NMR signal and value of measured induction are displayed on a monitor screen. (author)

  18. Automatic trend estimation

    CERN Document Server

    Vamos¸, C˘alin

    2013-01-01

    Our book introduces a method to evaluate the accuracy of trend estimation algorithms under conditions similar to those encountered in real time series processing. This method is based on Monte Carlo experiments with artificial time series numerically generated by an original algorithm. The second part of the book contains several automatic algorithms for trend estimation and time series partitioning. The source codes of the computer programs implementing these original automatic algorithms are given in the appendix and will be freely available on the web. The book contains clear statement of the conditions and the approximations under which the algorithms work, as well as the proper interpretation of their results. We illustrate the functioning of the analyzed algorithms by processing time series from astrophysics, finance, biophysics, and paleoclimatology. The numerical experiment method extensively used in our book is already in common use in computational and statistical physics.

  19. Working session 2: Tubing inspection

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, J. [Tecnatom, S.A. San Sebastian de los Reyes, Madrid (Spain); Tapping, R.L. [AECL, Chalk River, Ontario (Canada)

    1997-02-01

    This session was attended by delegates from 10 countries, and four papers were presented. A wide range of issues was tabled for discussion. Realizing that there was limited time available for more detailed discussion, three topics were chosen for the more detailed discussion: circumferential cracking, performance demonstration (to focus on POD and sizing), and limits of methods. Two other subsessions were organized: one dealt with some challenges related to the robustness of current inspection methods, especially with respect to leaving cracked tubes in service, and the other with developing a chart of current NDE technology with recommendations for future development. These three areas are summarized in turn, along with conclusions and/or recommendations. During the discussions there were four presentations. There were two (Canada, Japan) on eddy current probe developments, both of which addressed multiarray probes that would detect a range of flaws, one (Spain) on circumferential crack detection, and one (JRC, Petten) on the recent PISC III results.

  20. Neural Tube Defects

    OpenAIRE

    Greene, Nicholas D. E.; Copp, Andrew J.

    2014-01-01

    Neural tube defects (NTDs), including spina bifida and anencephaly, are severe birth defects of the central nervous system that originate during embryonic development when the neural tube fails to close completely. Human NTDs are multifactorial, with contributions from both genetic and environmental factors. The genetic basis is not yet well understood, but several nongenetic risk factors have been identified as have possibilities for prevention by maternal folic acid supplementation. Mechani...

  1. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  2. Automatic Wall Painting Robot

    OpenAIRE

    P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI

    2013-01-01

    The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time A...

  3. Automatic Program Reports

    OpenAIRE

    Lígia Maria da Silva Ribeiro; Gabriel de Sousa Torcato David

    2007-01-01

    To profit from the data collected by the SIGARRA academic IS, a systematic setof graphs and statistics has been added to it and are available on-line. Thisanalytic information can be automatically included in a flexible yearly report foreach program as well as in a synthesis report for the whole school. Somedifficulties in the interpretation of some graphs led to the definition of new keyindicators and the development of a data warehouse across the university whereeffective data consolidation...

  4. Automatic food decisions

    DEFF Research Database (Denmark)

    Mueller Loose, Simone

    Consumers' food decisions are to a large extent shaped by automatic processes, which are either internally directed through learned habits and routines or externally influenced by context factors and visual information triggers. Innovative research methods such as eye tracking, choice experiments...... and food diaries allow us to better understand the impact of unconscious processes on consumers' food choices. Simone Mueller Loose will provide an overview of recent research insights into the effects of habit and context on consumers' food choices....

  5. Automatic Differentiation Variational Inference

    OpenAIRE

    Kucukelbir, Alp; Tran, Dustin; Ranganath, Rajesh; Gelman, Andrew; Blei, David M.

    2016-01-01

    Probabilistic modeling is iterative. A scientist posits a simple model, fits it to her data, refines it according to her analysis, and repeats. However, fitting complex models to large data is a bottleneck in this process. Deriving algorithms for new models can be both mathematically and computationally challenging, which makes it difficult to efficiently cycle through the steps. To this end, we develop automatic differentiation variational inference (ADVI). Using our method, the scientist on...

  6. Automaticity or active control

    DEFF Research Database (Denmark)

    Tudoran, Ana Alina; Olsen, Svein Ottar

    This study addresses the quasi-moderating role of habit strength in explaining action loyalty. A model of loyalty behaviour is proposed that extends the traditional satisfaction–intention–action loyalty network. Habit strength is conceptualised as a cognitive construct to refer to the psychologic......, respectively, between intended loyalty and action loyalty. At high levels of habit strength, consumers are more likely to free up cognitive resources and incline the balance from controlled to routine and automatic-like responses....

  7. Automatic digital image registration

    Science.gov (United States)

    Goshtasby, A.; Jain, A. K.; Enslin, W. R.

    1982-01-01

    This paper introduces a general procedure for automatic registration of two images which may have translational, rotational, and scaling differences. This procedure involves (1) segmentation of the images, (2) isolation of dominant objects from the images, (3) determination of corresponding objects in the two images, and (4) estimation of transformation parameters using the center of gravities of objects as control points. An example is given which uses this technique to register two images which have translational, rotational, and scaling differences.

  8. Automatic force balance calibration system

    Science.gov (United States)

    Ferris, Alice T.

    1995-05-01

    A system for automatically calibrating force balances is provided. The invention uses a reference balance aligned with the balance being calibrated to provide superior accuracy while minimizing the time required to complete the calibration. The reference balance and the test balance are rigidly attached together with closely aligned moment centers. Loads placed on the system equally effect each balance, and the differences in the readings of the two balances can be used to generate the calibration matrix for the test balance. Since the accuracy of the test calibration is determined by the accuracy of the reference balance and current technology allows for reference balances to be calibrated to within +/-0.05% the entire system has an accuracy of +/-0.2%. The entire apparatus is relatively small and can be mounted on a movable base for easy transport between test locations. The system can also accept a wide variety of reference balances, thus allowing calibration under diverse load and size requirements.

  9. Aeronautical tubes and pipes

    Science.gov (United States)

    Beauclair, N.

    1984-12-01

    The main and subcomponent French suppliers of aircraft tubes and pipes are discussed, and the state of the industry is analyzed. Quality control is essential for tubes with regard to their i.d. and metallurgical compositions. French regulations do not allow welded seam tubes in hydraulic circuits unless no other form is available, and then rustproofed steel must be installed. The actual low level of orders for any run of tubes dictates that the product is only one of several among the manufacturers' line. Automation, both in NDT and quality control, assures that the tubes meet specifications. A total of 10 French companies participate in the industry, serving both civil and military needs, with some companies specializing only in titanium, steel, or aluminum materials. Concerns wishing to enter the market must upgrade their equipment to meet the higher aeronautical specifications and be prepared to furnish tubes and pipes that serve both functional and structural purposes simultaneously. Additionally, pipe-bending machines must also perform to tight specifications. Pipes can range from 0.2 mm exterior diameter to 40 mm, with wall thicknesses from 0.02 mm to 3 mm. A chart containing a list of manufacturers and their respective specifications and characteristics is presented, and a downtrend in production with reduction of personnel is noted.

  10. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    OpenAIRE

    Stolecki M.; Bijok H.; Kowal Ł.; Adamiec J.

    2015-01-01

    This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, ...

  11. Development of quadrupole focussing lenses for drift tube linac

    International Nuclear Information System (INIS)

    A linear accelerator comprising of Radio frequency quadruple (RFQ) and drift tube linac (DTL) is being developed by BARC. The alvarez type post-coupled cw DTL accelerates protons from an energy of 3 MeV to 20 MeV. The drift tube linac is excited in TM010 mode, wherein the particles are accelerated by longitudinal Electric fields at the gap crossings between drift tubes. The particles are subjected to transverse RF defocusing forces at the gap crossings due to the increasing electric fields in the gap. The transverse defocusing is corrected by housing magnetic quadrupole focussing lenses inside the drift tubes. The permanent magnet quadrupoles are placed inside the hermetically sealed drift tubes and provide constant magnetic field gradient in the beam aperture. The drift tubes are mounted concentrically inside the resonating DTL tank and are attached to the tank body with stems. Rare earth permanent magnets have been used to achieve the high field gradient. The drift tube body is subjected to RF heating due to eddy currents and hence the sealed drift tubes are to be cooled from inside. The temperature rise of the drift tube assemblies has to be limited to avoid demagnetization of permanent magnets and also to limit thermal expansion of the tubes. This paper discusses various aspects of magnetic design, selection of magnetic materials and the engineering development involved in the assembly of the drift tubes. (author)

  12. Stability of spiral welded tubes in Quay Walls

    OpenAIRE

    Gresnigt, A. M.; van Es, S.H.J.

    2013-01-01

    A European research project (RFCS) has started to provide economic and safe guidance for the design of spirally welded tubes in combined walls. The main motivation for this project called COMBITUBE is that the current Eurocode 3 regulations for tubes in quay walls lead to uneconomic designs, because of poor local buckling design rules for these tubes. Because the most important load in quay walls is bending due to earth load, economic design implies a high diameter to wall thickness ratio. Fo...

  13. Novel Photo Multiplier Tubes for the Cherenkov Telescope Array Project

    OpenAIRE

    Toyama, Takeshi; Mirzoyan, Razmik; Dickinson, Hugh; Fruck, Christian; Hose, Jürgen; Kellermann, Hanna; Knötig, Max; Lorenz, Eckart; Menzel, Uta; Nakajima, Daisuke; Orito, Reiko; Paneque, David; Schweizer, Thomas; Teshima, Masahiro; Yamamoto, Tokonatsu

    2013-01-01

    Currently the standard light sensors for imaging atmospheric Cherenkov telescopes are the classical photo multiplier tubes that are using bialkali photo cathodes. About eight years ago we initiated an improvement program with the Photo Multiplier Tube (PMT) manufacturers Hamamatsu (Japan), Electron Tubes Enterprises (England) and Photonis (France) for the needs of imaging atmospheric Cherenkov telescopes. As a result, after about 40 years of stagnation of the peak Quantum Efficiency (QE) on t...

  14. Experience with a new ultrasonic inspection system for non-destructive examination of canning tubes

    International Nuclear Information System (INIS)

    The Risoe/HV Tube Inspection System is designed for fast automatic inspection of precision tubes for dimensions and defects. The system is built around a rotating water chamber with eight ultrasonic transducers. The tube handling and evaluation of the results could be made in different ways by various combination of modules in the system. By standard inspection of canning tubes for nuclear fuel, the inspection speed is 6m of tube per minute with the chamber rotating 3000rev/min; tubes are fed through the system without rotation, and, owing to the conical tube guide used, very gentle treatment of the tubes is assured. Evaluation and development work on this system has been performed during the last three years and has been based on practical experience with tube inspection. The accuracy and stability of the system has been improved by innovation in both the mechanical system (especially water circulation and temperature regulation) and the electronic modules (ultrasonic equipment). Also the ultrasonic transducers have been studied and changed. The calibration procedure has been simplified and improved both for dimensions and defects. The influence of the different improvements on stability and accuracy during actual tube inspection has been ascertained by repeated inspection of the same 17 tubes. The results from these inspections indicate an accuracy and stability of less than 5μm on dimension measurements during actual tube examinations. (author)

  15. Development of automatic inspection and maintenance technology for steam generator in nuclear power plants

    International Nuclear Information System (INIS)

    In this paper, we propose a new approach to the development of the automatic vision system to examine and repair the steam generator tubes at remote distance. In nuclear power plants, workers are reluctant of works in steam generator because of the high radiation environment and limited working space. It is strongly recommended that the examination and maintenance works be done by an automatic system for the protection of the operator from the radiation exposure. Digital signal processors are used in implementing real time recognition and examination of steam generator tubes in the proposed vision system. Performance of proposed digital vision system is illustrated by simulation and experiment for similar steam generator model

  16. Automatic patient dose registry and clinical audit on line for mammography

    International Nuclear Information System (INIS)

    The use of automatic registry systems for patient dose in digital mammography allows clinical audit and patient dose analysis of the whole sample of individual mammography exposures while fulfilling the requirements of the European Directives and other international recommendations. Further parameters associated with radiation exposure (tube voltage, X-ray tube output and HVL values for different kVp and target/filter combinations, breast compression, etc.) should be periodically verified and used to evaluate patient doses. This study presents an experience in routine clinical practice for mammography using automatic systems. (authors)

  17. Caring for Tube-Fed Children: A Review of Management, Tube Weaning, and Emotional Considerations.

    Science.gov (United States)

    Edwards, Sarah; Davis, Ann M; Bruce, Amanda; Mousa, Hayat; Lyman, Beth; Cocjin, Jose; Dean, Kelsey; Ernst, Linda; Almadhoun, Osama; Hyman, Paul

    2016-07-01

    Enteral nutrition is the practice of delivering nutrition to the gut either orally or through a tube or other device. Many children are reliant on enteral feedings to either supplement their nutrition or as a complete source of their nutrition. Managing children on tube feedings requires a team of providers to work through such dilemmas as feeding schedules, weaning from tube feeding, sensory implications of tube feeding, treatment of pain or nausea associated with eating, oral-motor issues, and behavioral issues in the child and family. The purpose of the current review is to summarize the multidisciplinary aspects of enteral feeding. The multidisciplinary team consists of a variable combination of an occupational therapist, speech-language pathologist, gastroenterologist, psychologist, nurse, pharmacist, and dietitian. Children who have minimal oral feeding experience and are fed via a nasogastric or gastrostomy tube often develop oral aversions. Limited data support that children with feeding disorders are more likely to have sensory impairment and that early life pain experiences contribute to feeding refusal. There are inpatient and outpatient programs for weaning patients from tube feeding to eating. The parent-child interaction is an important part of the assessment and treatment of the tube-fed child. This review also points out many information gaps, including data on feeding schedules, blenderized tube feedings, the best methods for weaning children off enteral feedings, the efficacy of chronic pain medications with tube-fed children, and, finally, the necessity of the assessment of parental stress among all parents of children who are tube fed. PMID:25791833

  18. Preanalytical management: serum vacuum tubes validation for routine clinical chemistry

    Science.gov (United States)

    Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Picheth, Geraldo; Guidi, Gian Cesare

    2012-01-01

    Introduction The validation process is essential in accredited clinical laboratories. Aim of this study was to validate five kinds of serum vacuum tubes for routine clinical chemistry laboratory testing. Materials and methods: Blood specimens from 100 volunteers in five diff erent serum vacuum tubes (Tube I: VACUETTE®, Tube II: LABOR IMPORT®, Tube III: S-Monovette®, Tube IV: SST® and Tube V: SST II®) were collected by a single, expert phlebotomist. The routine clinical chemistry tests were analyzed on cobas® 6000 module. The significance of the diff erences between samples was assessed by paired Student’s t-test after checking for normality. The level of statistical significance was set at P < 0.005. Finally, the biases from Tube I, Tube II, Tube III, Tube IV and Tube V were compared with the current desirable quality specifications for bias (B), derived from biological variation. Results and conclusions: Basically, our validation will permit the laboratory or hospital managers to select the brand’s vacuum tubes validated according him/her technical or economical reasons, in order to perform the following laboratory tests: glucose, total cholesterol, high density lipoprotein-cholesterol, triglycerides, total protein, albumin, blood urea nitrogen, uric acid, alkaline phosphatise, aspartate aminotransferase, gamma-glutamyltransferase, lactate dehydrogenase, creatine kinase, total bilirubin, direct bilirubin, calcium, iron, sodium and potassium. On the contrary special attention will be required if the laboratory already performs creatinine, amylase, phosphate and magnesium determinations and the quality laboratory manager intend to change the serum tubes. We suggest that laboratory management should both standardize the procedures and frequently evaluate the quality of in vitro diagnostic devices. PMID:22838184

  19. Steam generator tube fretting - Darlington NGS experience

    International Nuclear Information System (INIS)

    Early signs of tube fretting in the U-bend region of Darlington NGS Steam Generators (SGs) were observed during the metallurgical examination of the removed peripheral tube U-bend sections from Unit 4 SG3 in 1995. During a forced outage in early 1998, Eddy Current (ECT) tube inspections in Unit 2 SG4 revealed more extensive fretting of the tubes at the U-bend AVB support locations. Subsequently in the period of 1999-2001, planned Eddy Current tube inspections have been carried out in all units covering all SGs. These inspections have revealed considerable U-bend tube fretting with a number of these fret depths in excess of 40% tw. Evaluation of the ECT and UT results, in conjunction with engineering assessment of the SG design and construction, have determined tube fretting in the U-bend region as an active and reportable degradation mechanism in these SGs. To date, all 16 Darlington SGs have undergone a major ECT inspection. In these inspections as a minimum, the identified fretting region of the U-bend has been adequately covered. Analyses of the inspection results have been carried out to provide trends and observations of the fretting in the U-bend. These showed the fretted U-bend tubes to be localized in the area bounded by Rows 70 and above, and Columns 39 to 83 which has been defined as the 'Area at Risk' of U-bend fretting for Darlington SGs. In the distribution of the frets at the U-bend support locations, they showed a strong biasing of the fretting towards the cold leg supports with the mean centered a third the way between CU4 and CU3. A general understanding of the 'Root Cause of Fretting' shows it to be associated with tube clearance, which invariably results and acts together with conditions of insufficient support preload. While the fretting by tube tends to exhibit a certain degree of randomness, the fretting remains localized to the 'Area at Risk'. This offers a unique opportunity of localized corrective measures that are both simpler in design

  20. Geiger-Muller tubes

    International Nuclear Information System (INIS)

    A Geiger-Muller tube designed for use in an environment (for example, mounted on a rock drill) where subjected to mechanical shock and vibration has a tensioned anode wire secured by welding to securement members between first and second mounts at opposite ends of the tube envelope. The wire tension is adjusted to a high value with a screwable-adjustment means which is locked eg. by a spot-weld or by a locking nut, in the adjusted position, so that the natural frequency of the vibration of the tensioned wire does not resonate with (and may be much higher than) the frequencies to which the tube is subjected in use. The wire frequency is typically in excess of 400Hz and even 500Hz. The adjustment means may be included in the mount via which the envelope is evacuated and back-filled with the ionizible gas, and a gas-tight seal can be provided around this part of the mount, for example by sealing off the gas pump tube. However the adjustment means may be designed into another part of the tube, for example using telescopic parts of the envelope whose sliding junction is made gas tight with a flexible seal. (author)

  1. Categorising YouTube

    Directory of Open Access Journals (Sweden)

    Thomas Mosebo Simonsen

    2011-09-01

    Full Text Available This article provides a genre analytical approach to creating a typology of the User Generated Content (UGC of YouTube. The article investigates the construction of navigationprocesses on the YouTube website. It suggests a pragmatic genre approach that is expanded through a focus on YouTube’s technological affordances. Through an analysis of the different pragmatic contexts of YouTube, it is argued that a taxonomic understanding of YouTube must be analysed in regards to the vacillation of a user-driven bottom-up folksonomy and a hierarchical browsing system that emphasises a culture of competition and which favours the already popular content of YouTube. With this taxonomic approach, the UGC videos are registered and analysed in terms of empirically based observations. The article identifies various UGC categories and their principal characteristics. Furthermore, general tendencies of the UGC within the interacting relationship of new and old genres are discussed. It is argued that the utility of a conventional categorical system is primarily of analytical and theoretical interest rather than as a practical instrument.

  2. Effect of tube size on electromagnetic tube bulging

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The commercial finite code ANSYS was employed for the simulation of the electromagnetic tube bulging process. The finite element model and boundary conditions were thoroughly discussed. ANSYS/EMAG was used to model the time varying electromagnetic field in order to obtain the radial and axial magnetic pressure acting on the tube. The magnetic pressure was then used as boundary conditions to model the high velocity deformation of various length tube with ANSYS/LSDYNA. The time space distribution of magnetic pressure on various length tubes was presented. Effect of tube size on the distribution of radial magnetic pressure and axial magnetic pressure and high velocity deformation were discussed. According to the radial magnetic pressure ratio of tube end to tube center and corresponding dimensionless length ratio of tube to coil, the free electromagnetic tube bulging was studied in classification. The calculated results show good agreements with practice.

  3. Stability of spiral welded tubes in Quay Walls

    NARCIS (Netherlands)

    Gresnigt, A.M.; van Es, S.H.J.

    2013-01-01

    A European research project (RFCS) has started to provide economic and safe guidance for the design of spirally welded tubes in combined walls. The main motivation for this project called COMBITUBE is that the current Eurocode 3 regulations for tubes in quay walls lead to uneconomic designs, because

  4. Analysis of tubes filled with charged electron gas

    OpenAIRE

    Karrmann, Stefan

    2011-01-01

    We show that tubes filled with electron gas, as presented by A.Bolonkin, are not possible with current materials. First, the pressure of the charges on the outer surface cancel almost all of the electrostatic pressure of the inner electrons. Second, due to the mutually repulsion most of the electrons are in the outmost shell of the tube and not individually free.

  5. Status of special reactor process tube loadings, November 1, 1965

    Energy Technology Data Exchange (ETDEWEB)

    Bown, R.W.

    1965-11-10

    This report gives the status of production test control tube loadings in reactor process tubes containing significant amounts of SS materials. Data are given in table form. For further description of column headings and the current discharge goal exposure plan refer to Document RL-REA-837.

  6. Advances in electrometer vacuum tube design

    Science.gov (United States)

    1970-01-01

    Single-ended, miniature-cathode tube with a relatively low grid current level is constructed. Adequate cathode temperature at relatively low heater power drain is provided by designing the supporting spacers to provide a square cathode hole. Method of assembling the mount and bonding the elements is discussed.

  7. Automatic radioactive waste recycling

    International Nuclear Information System (INIS)

    The production of a plutonium ingot by calcium reduction process at CEA/Valduc generates a residue called 'slag'. This article introduces the recycling unit which is dedicated to the treatment of slags. The aim is to separate and to recycle the plutonium trapped in this bulk on the one hand, and to generate a disposable waste from the slag on the other hand. After a general introduction of the facilities, some elements will be enlightened, particularly the dissolution step, the filtration and the drying equipment. Reflections upon technological constraints will be proposed, and the benefits of a fully automatic recycling unit of nuclear waste will also be stressed. (authors)

  8. Automatic Configuration in NTP

    Institute of Scientific and Technical Information of China (English)

    Jiang Zongli(蒋宗礼); Xu Binbin

    2003-01-01

    NTP is nowadays the most widely used distributed network time protocol, which aims at synchronizing the clocks of computers in a network and keeping the accuracy and validation of the time information which is transmitted in the network. Without automatic configuration mechanism, the stability and flexibility of the synchronization network built upon NTP protocol are not satisfying. P2P's resource discovery mechanism is used to look for time sources in a synchronization network, and according to the network environment and node's quality, the synchronization network is constructed dynamically.

  9. Marketing Strategy of YouTube in the Czech Republic

    OpenAIRE

    Hurychová, Andrea

    2012-01-01

    The goals of the thesis are to present YouTube in the Czech Republic, to discuss its entire business model, analyze the main local competitors and mostly to suggest marketing strategy that will strengthen the position of YouTube as an online medium. The current trends in the internet society are introduced as well as the role of social media in order to understand how these factors are related to the position of YouTube in marketing. From general YouTube introduction the situation of this pla...

  10. Status of steam generator tubing integrity at Jaslovske Bohunice NPP

    Energy Technology Data Exchange (ETDEWEB)

    Cepcek, S. [Nuclear Regulatory Authority of the Slovak Republic, Trnava (Slovakia)

    1997-02-01

    Steam generator represents one of the most important component of nuclear power plants. Especially, loss of tubing integrity of steam generators can lead to the primary coolant leak to secondary circuit and in worse cases to the unit shut down or to the PTS events occurrence. Therefore, to ensure the steam generator tubing integrity and the current knowledge about tube degradation propagation and development is of the highest importance. In this paper the present status of steam generator tubing integrity in operated NPP in Slovak Republic is presented.

  11. Automatic summary evaluation based on text grammars

    OpenAIRE

    Branny, Emilia

    2007-01-01

    In this paper, I describe a method for evaluating automatically generated text summaries. The method is inspired by research in text grammars by Teun Van Dijk. It addresses a text as a complex structure, the elements of which are interconnected both on the level of form and meaning, and the well-formedness of which should be described on both of these levels. The method addresses current problems of summary evaluation methods, especially the problem of quantifying informativity, as well as th...

  12. Kajian Efektifitas Sistem Struktur Tube Dengan Sistem Struktur Tube In Tube Di Bawah Beban Gempa

    OpenAIRE

    Sihotang, Dian Frisca

    2010-01-01

    Berkembangnya teknologi telah melahirkan berbagai sistem struktur bangunan tahan gempa, seperti penggunaan sistem tube.Tube adalah merupakan frame penahan gaya yang menahan gaya gaya lateral dengan struktur kantilever kotak yang memiliki jarak kolom yang berdekatan yang dipasang pada sekeliling gedung, sehingga penampilan wajah depan gedung seperti lubang jendela jendela yang terbuka. Rancangan tube ini kemudian dimodifikasi lagi dengan menambah pengaku pada bagian dalam ( konsep tube in tube...

  13. Development of techniques for the fabrication of non-destructive examination of tube-to-tube-sheet connections for sodium-heated steam generators

    International Nuclear Information System (INIS)

    Techniques involving the use of ferritic materials of proven reliability have been studied. Tube-to-tube-sheet connections have been manufactured by automatic butt-welding without filler metal using specially miniaturized torches. The paper discusses also techniques for localized heat treatment which can be employed both for production and for in-service repairs. Techniques have been developed for gamma radiographic inspection and ultrasonic testing suitable for welds of less than 10 mm internal diameter. The ultrasonic technique permits a complete inspection of welds on both tube sheets. The reflected signals are continuously recorded so that the data can be compared with those obtained during in-service inspection. (author)

  14. Semi-automatic analysis of fire debris

    Science.gov (United States)

    Touron; Malaquin; Gardebas; Nicolai

    2000-05-01

    Automated analysis of fire residues involves a strategy which deals with the wide variety of received criminalistic samples. Because of unknown concentration of accelerant in a sample and the wide range of flammable products, full attention from the analyst is required. Primary detection with a photoionisator resolves the first problem, determining the right method to use: the less responsive classical head-space determination or absorption on active charcoal tube, a better fitted method more adapted to low concentrations can thus be chosen. The latter method is suitable for automatic thermal desorption (ATD400), to avoid any risk of cross contamination. A PONA column (50 mx0.2 mm i.d.) allows the separation of volatile hydrocarbons from C(1) to C(15) and the update of a database. A specific second column is used for heavy hydrocarbons. Heavy products (C(13) to C(40)) were extracted from residues using a very small amount of pentane, concentrated to 1 ml at 50 degrees C and then placed on an automatic carousel. Comparison of flammables with referenced chromatograms provided expected identification, possibly using mass spectrometry. This analytical strategy belongs to the IRCGN quality program, resulting in analysis of 1500 samples per year by two technicians. PMID:10802196

  15. Neural tube defects

    OpenAIRE

    M.E. Marshall

    1981-01-01

    Neural tube defects refer to any defect in the morphogenesis of the neural tube, the most common types being spina bifida and anencephaly. Spina bifida has been recognised in skeletons found in north-eastern Morocco and estimated to have an age of almost 12 000 years. It was also known to the ancient Greek and Arabian physicians who thought that the bony defect was due to the tumour. The term spina bifida was first used by Professor Nicolai Tulp of Amsterdam in 1652. Many other terms have bee...

  16. MARZ: Manual and automatic redshifting software

    Science.gov (United States)

    Hinton, S. R.; Davis, Tamara M.; Lidman, C.; Glazebrook, K.; Lewis, G. F.

    2016-04-01

    The Australian Dark Energy Survey (OzDES) is a 100-night spectroscopic survey underway on the Anglo-Australian Telescope using the fibre-fed 2-degree-field (2dF) spectrograph. We have developed a new redshifting application MARZ with greater usability, flexibility, and the capacity to analyse a wider range of object types than the RUNZ software package previously used for redshifting spectra from 2dF. MARZ is an open-source, client-based, Javascript web-application which provides an intuitive interface and powerful automatic matching capabilities on spectra generated from the AAOmega spectrograph to produce high quality spectroscopic redshift measurements. The software can be run interactively or via the command line, and is easily adaptable to other instruments and pipelines if conforming to the current FITS file standard is not possible. Behind the scenes, a modified version of the AUTOZ cross-correlation algorithm is used to match input spectra against a variety of stellar and galaxy templates, and automatic matching performance for OzDES spectra has increased from 54% (RUNZ) to 91% (MARZ). Spectra not matched correctly by the automatic algorithm can be easily redshifted manually by cycling automatic results, manual template comparison, or marking spectral features.

  17. Automatic readout micrometer

    International Nuclear Information System (INIS)

    A measuring system is disclosed for surveying and very accurately positioning objects with respect to a reference line. A principal use of this surveying system is for accurately aligning the electromagnets which direct a particle beam emitted from a particle accelerator. Prior art surveying systems require highly skilled surveyors. Prior art systems include, for example, optical surveying systems which are susceptible to operator reading errors, and celestial navigation-type surveying systems, with their inherent complexities. The present invention provides an automatic readout micrometer which can very accurately measure distances. The invention has a simplicity of operation which practically eliminates the possibilities of operator optical reading error, owning to the elimination of traditional optical alignments for making measurements. The invention has an extendable arm which carries a laser surveying target. The extendable arm can be continuously positioned over its entire length of travel by either a coarse or fine adjustment without having the fine adjustment outrun the coarse adjustment until a reference laser beam is centered on the target as indicated by a digital readout. The length of the micrometer can then be accurately and automatically read by a computer and compared with a standardized set of alignment measurements. Due to its construction, the micrometer eliminates any errors due to temperature changes when the system is operated within a standard operating temperature range

  18. Automatic personnel contamination monitor

    International Nuclear Information System (INIS)

    United Nuclear Industries, Inc. (UNI) has developed an automatic personnel contamination monitor (APCM), which uniquely combines the design features of both portal and hand and shoe monitors. In addition, this prototype system also has a number of new features, including: micro computer control and readout, nineteen large area gas flow detectors, real-time background compensation, self-checking for system failures, and card reader identification and control. UNI's experience in operating the Hanford N Reactor, located in Richland, Washington, has shown the necessity of automatically monitoring plant personnel for contamination after they have passed through the procedurally controlled radiation zones. This final check ensures that each radiation zone worker has been properly checked before leaving company controlled boundaries. Investigation of the commercially available portal and hand and shoe monitors indicated that they did not have the sensitivity or sophistication required for UNI's application, therefore, a development program was initiated, resulting in the subject monitor. Field testing shows good sensitivity to personnel contamination with the majority of alarms showing contaminants on clothing, face and head areas. In general, the APCM has sensitivity comparable to portal survey instrumentation. The inherit stand-in, walk-on feature of the APCM not only makes it easy to use, but makes it difficult to bypass. (author)

  19. The Choking Game on YouTube

    OpenAIRE

    Defenderfer, Ellen K.; Austin, Jillian E.; Davies, W. Hobart

    2016-01-01

    The choking game (TCG) is an adolescent activity in which asphyxiation is used to obtain a “high,” occasionally resulting in seizures or death. A plethora of TCG information is available through YouTube, though this content has not been evaluated recently. The current study described TCG as portrayed in YouTube videos and compared views and ratings of TCG videos to unrelated videos. The TCG videos demonstrated diverse methods of asphyxiation, with a minority showing injury to the participants...

  20. Digital Radiography Qualification of Tube Welding

    Science.gov (United States)

    Carl, Chad

    2012-01-01

    The Orion Project will be directing Lockheed Martin to perform orbital arc welding on commodities metallic tubing as part of the Multi Purpose Crew Vehicle assembly and integration process in the Operations and Checkout High bay at Kennedy Space Center. The current method of nondestructive evaluation is utilizing traditional film based x-rays. Due to the high number of welds that are necessary to join the commodities tubing (approx 470), a more efficient and expeditious method of nondestructive evaluation is desired. Digital radiography will be qualified as part of a broader NNWG project scope.

  1. Detection of ''beading faults'' in welded tubes

    International Nuclear Information System (INIS)

    In the steel tube industry the word ''beading'' refers to a highly localised leak affecting the welded zone. During the pneumatic test its flow rate is generally very low no more than a few thousandths of a mm3/second. Detection of such a fault by this test is consequently slow, and those which are choked or at the limit of leakage may escape detection. For greater safety, the tube technician is now using non-destructive testing methods such as eddy-currents and ultrasonics

  2. Eddy currents signal processing for steam generator inspection in PWR nuclear power plants

    International Nuclear Information System (INIS)

    Steam generator tubes in nuclear power plants are periodically checked by means of eddy current probes. The output of a probe is composed of three types of signals: known events (rolling zone, support plates, U-bend part), noise (mainly metallurgical noise) and possible flaws. The latter are random transients, both in arrival time and in shape: they have to be detected and then estimated, before to be fed to the high level stages of a diagnostics system. The objective of the study presented is to develop a semi-automatic system, which could manage and process more than 1 M-bytes of data per tube and provide an operator with reliable diagnostics proposals within a few minutes. This can be achieved only by cooperation of several digital signal processing techniques: detection, segmentation, estimation, noise subtraction, adaptive filtering, modelization, pattern recognition. The paper describes some of these items

  3. Intelligent Space Tube Optimization for speeding ground water remedial design.

    Science.gov (United States)

    Kalwij, Ineke M; Peralta, Richard C

    2008-01-01

    An innovative Intelligent Space Tube Optimization (ISTO) two-stage approach facilitates solving complex nonlinear flow and contaminant transport management problems. It reduces computational effort of designing optimal ground water remediation systems and strategies for an assumed set of wells. ISTO's stage 1 defines an adaptive mobile space tube that lengthens toward the optimal solution. The space tube has overlapping multidimensional subspaces. Stage 1 generates several strategies within the space tube, trains neural surrogate simulators (NSS) using the limited space tube data, and optimizes using an advanced genetic algorithm (AGA) with NSS. Stage 1 speeds evaluating assumed well locations and combinations. For a large complex plume of solvents and explosives, ISTO stage 1 reaches within 10% of the optimal solution 25% faster than an efficient AGA coupled with comprehensive tabu search (AGCT) does by itself. ISTO input parameters include space tube radius and number of strategies used to train NSS per cycle. Larger radii can speed convergence to optimality for optimizations that achieve it but might increase the number of optimizations reaching it. ISTO stage 2 automatically refines the NSS-AGA stage 1 optimal strategy using heuristic optimization (we used AGCT), without using NSS surrogates. Stage 2 explores the entire solution space. ISTO is applicable for many heuristic optimization settings in which the numerical simulator is computationally intensive, and one would like to reduce that burden. PMID:18754799

  4. Numerical calculation of vacuum tube power amplifier mode of operation

    International Nuclear Information System (INIS)

    As result of INR RF system upgrade new vacuum tubes GI-71A and GI-57A were installed in the final and driver stages instead of GI-54A and GI-51A, manufacture of which had been stopped 20 years ago. New tubes are distinguished from former ones and a problem of optimization of the power amplifier mode of operation became the main one. This is connected not only with new type of the vacuum tubes, but also with the necessity of using, as much as possible, the former power amplifier basic hardware. The paper consists of two parts. In the first one a way of the PA vacuum tube load (equivalent resistance) calculation is considered. In the second one the model for determination of vacuum tube mode of operation is presented. By means of the model the vacuum tube specified in parameters, such as plate voltage, grid-cathode automatic bias, anode load etc, allow right now determining output parameters and efficiency of the power amplifier.

  5. A method of automatic control procedures cardiopulmonary resuscitation

    Science.gov (United States)

    Bureev, A. Sh.; Zhdanov, D. S.; Kiseleva, E. Yu.; Kutsov, M. S.; Trifonov, A. Yu.

    2015-11-01

    The study is to present the results of works on creation of methods of automatic control procedures of cardiopulmonary resuscitation (CPR). A method of automatic control procedure of CPR by evaluating the acoustic data of the dynamics of blood flow in the bifurcation of carotid arteries and the dynamics of air flow in a trachea according to the current guidelines for CPR is presented. Evaluation of the patient is carried out by analyzing the respiratory noise and blood flow in the interspaces between the chest compressions and artificial pulmonary ventilation. The device operation algorithm of automatic control procedures of CPR and its block diagram has been developed.

  6. Experience with a new ultrasonic inspection system for non-destructive examination of canning tubes

    International Nuclear Information System (INIS)

    The Risoe/HV Tube Inspection System is designed for the fast automatic inspection of precision tubes. Work has been carried out on this system for the last 3 years. Its accuracy and stability have been improved by innovation in both the mechanical system (specially the water circulation and temperature regulation) and the electronic modules (the ultrasonic equipment). Also the ultrasonic transducers have been studied and changed. The calibration procedure has been simplified and furthermore improved, both for dimensions and defects. (author)

  7. Prawns in Bamboo Tube

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Ingredients: 400 grams Jiwei prawns, 25 grams pork shreds, 5 grams sliced garlic. Condiments: 5 grams cooking oil, minced ginger root and scallions, cooking wine, salt, pepper and MSG (optional) Method: 1. Place the Shelled prawns into a bowl and mix with all the condiments. 2. Stuff the prawns into a fresh bamboo tube,

  8. Thoughts of accelerator tubes

    International Nuclear Information System (INIS)

    A brief, subjective review is given of mechanisms that may be limiting electrostatic accelerator tubes to present levels of performance. Suggestions are made for attacking these limitations with the purpose of stimulating the thinking of designers and users of electrostatic accelerators

  9. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    Directory of Open Access Journals (Sweden)

    Stolecki M.

    2015-09-01

    Full Text Available This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301 austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614, and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

  10. Evaluation of reliability of EC inspection of VVER SG tubes

    International Nuclear Information System (INIS)

    Evaluation of eddy current data collected during inspection of VVER steam generators is very complex task because of numerous parameters which have affect on eddy current signals. That was the reason that recently ago INETEC has started related scientific project in order to evaluate the reliability of eddy current (EC) inspection of VVER steam generator (SG) tubing. In the scope of project the following objectives will be investigated: 1. Determination of POD (Probability of detection) of various types degradation cracks, where their basic parameters are variables (basic parameters are depth, length, width, orientation, number) on three different sets of tubes (clean ideal tubes, tubes with pilgering, tubes electroplated with copper) 2. Sizing quality (accuracy, repeatability) (same data sets as defined in 1.) 3. Effect of fill factor on POD and sizing quality. 4. Effect of tube bends on POD and sizing quality. 5. Effect of other tube geometry variations on POD and sizing quality (tube ovality, transition zone region, expanded (rolled) part of tube, dents, dings). Investigation will start with bobbin probe technique which is the most used technique for general purpose VVER tube examination. Since INETEC is the only world company which successfully developed and applied rotating probe technique for VVER SG tubes, scope of the project will be extended on rotating probe technique utilizing 'pancake' and 'point' coil. Method reliability will be investigated first on the huge set of EDM notches representing various defect morphologies and simulating different factors, and the second part will be investigated on sets of degradation defects obtained by artificial corrosion. In the scope of the project the measures for enhancing the method reliability have to be determined. This considers the proper definition of parameters of examination system, as well as establishment of the suitable analysis procedures. This article presents the temporary results of the first part of

  11. Automatic control system for measuring currents produced by ionization chambers; Automatizacao de um sistema de medidas de correntes produzidas por camaras de ionizacao e aplicacao na calibracao do {sup 18}F e {sup 153}Sm

    Energy Technology Data Exchange (ETDEWEB)

    Brancaccio, Franco

    2002-07-01

    Ionization Chambers in current mode operation are usually used in Nuclear Metrology. Activity measurements are quickly performed by Ionization Chambers, with very good precision. For this purpose measurements of very low ionization currents, carried out by high quality instrumentation, are required. Usually, electrometers perform the current integration method under command of signals from an automation system, in order to reduce the measurement uncertainties. Among the measurement systems at the Laboratorio de Metrologia Nuclear (LMN) of IPEN, there are two ionization chamber systems. In the present work, an automation system developed for current integration measurements is described. This automation system is composed by software (graphic interface and control) and an electronic module connected to a microcomputer, by means of a commercial data acquisition card. Several test measurements were performed in order to determine the intrinsic uncertainty, linearity and stability of the system. Using calibrated radioactive solutions, the IG12/A20 chamber calibration factors for {sup 18}F and {sup 153}Sm were obtained, making possible to determine activities of these radionuclides. (author)

  12. The Large-Scale Sugarcane Stripper with Automatic Feeding

    OpenAIRE

    Jiaxiang Lin; Wenjie Yan; Jiaping Lin

    2012-01-01

    This study mainly introduce the large-scale sugarcane stripper with automatic feeding, which including the automatic feeding module, cleaning leaves module, collecting module and control module. The machine is an important part of the segmental type sugarcane harvester, using to solve the highest labor intensity problem of cleaning leaves. Collecting the hilly areas sugarcane and cleaning their leaves, can greatly improve the labor productivity and changing the current mode of sugarcane harvest.

  13. JAPS: an automatic parallelizing system based on JAVA

    Institute of Scientific and Technical Information of China (English)

    杜建成; 陈道蓄; 谢立

    1999-01-01

    JAPS is an automatic parallelizing system based on JAVA running on NOW. It implements the automatic process from dependence analysis to parallel execution. The current version of JAPS can exploit functional parallelism and the detection of data parallelism will be incorporated in the new version, which is underway. The framework and key techniques of JAPS are presented. Specific topics discussed are task partitioning, summary information collection, data dependence analysis, pre-scheduling and dynamic scheduling, etc.

  14. Design of Automatic Extraction Algorithm of Knowledge Points for MOOCs

    OpenAIRE

    Haijian Chen; Dongmei Han; Yonghui Dai; Lina Zhao

    2015-01-01

    In recent years, Massive Open Online Courses (MOOCs) are very popular among college students and have a powerful impact on academic institutions. In the MOOCs environment, knowledge discovery and knowledge sharing are very important, which currently are often achieved by ontology techniques. In building ontology, automatic extraction technology is crucial. Because the general methods of text mining algorithm do not have obvious effect on online course, we designed automatic extracting course ...

  15. Automatic Speaker Recognition System

    Directory of Open Access Journals (Sweden)

    Parul,R. B. Dubey

    2012-12-01

    Full Text Available Spoken language is used by human to convey many types of information. Primarily, speech convey message via words. Owing to advanced speech technologies, people's interactions with remote machines, such as phone banking, internet browsing, and secured information retrieval by voice, is becoming popular today. Speaker verification and speaker identification are important for authentication and verification in security purpose. Speaker identification methods can be divided into text independent and text-dependent. Speaker recognition is the process of automatically recognizing speaker voice on the basis of individual information included in the input speech waves. It consists of comparing a speech signal from an unknown speaker to a set of stored data of known speakers. This process recognizes who has spoken by matching input signal with pre- stored samples. The work is focussed to improve the performance of the speaker verification under noisy conditions.

  16. Automatic Wall Painting Robot

    Directory of Open Access Journals (Sweden)

    P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI

    2013-07-01

    Full Text Available The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time And Effort Consuming. When Construction Workers And Robots Are Properly Integrated In Building Tasks, The Whole Construction Process Can Be Better Managed And Savings In Human Labour And Timing Are Obtained As A Consequence. In Addition, It Would Offer The Opportunity To Reduce Or Eliminate Human Exposure To Difficult And Hazardous Environments, Which Would Solve Most Of The Problems Connected With Safety When Many Activities Occur At The Same Time. These Factors Motivate The Development Of An Automated Robotic Painting System.

  17. Automatic alkaloid removal system.

    Science.gov (United States)

    Yahaya, Muhammad Rizuwan; Hj Razali, Mohd Hudzari; Abu Bakar, Che Abdullah; Ismail, Wan Ishak Wan; Muda, Wan Musa Wan; Mat, Nashriyah; Zakaria, Abd

    2014-01-01

    This alkaloid automated removal machine was developed at Instrumentation Laboratory, Universiti Sultan Zainal Abidin Malaysia that purposely for removing the alkaloid toxicity from Dioscorea hispida (DH) tuber. It is a poisonous plant where scientific study has shown that its tubers contain toxic alkaloid constituents, dioscorine. The tubers can only be consumed after it poisonous is removed. In this experiment, the tubers are needed to blend as powder form before inserting into machine basket. The user is need to push the START button on machine controller for switching the water pump ON by then creating turbulence wave of water in machine tank. The water will stop automatically by triggering the outlet solenoid valve. The powders of tubers are washed for 10 minutes while 1 liter of contaminated water due toxin mixture is flowing out. At this time, the controller will automatically triggered inlet solenoid valve and the new water will flow in machine tank until achieve the desire level that which determined by ultra sonic sensor. This process will repeated for 7 h and the positive result is achieved and shows it significant according to the several parameters of biological character ofpH, temperature, dissolve oxygen, turbidity, conductivity and fish survival rate or time. From that parameter, it also shows the positive result which is near or same with control water and assuming was made that the toxin is fully removed when the pH of DH powder is near with control water. For control water, the pH is about 5.3 while water from this experiment process is 6.0 and before run the machine the pH of contaminated water is about 3.8 which are too acid. This automated machine can save time for removing toxicity from DH compared with a traditional method while less observation of the user. PMID:24783795

  18. Mechanical properties of ceramic composite tubes

    Energy Technology Data Exchange (ETDEWEB)

    Curtin, W.A.; Oleksuk, L.L.; Reifsnider, K.L. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Stinton, D.P. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Results of axial tension tests on SiC/SiC tubular ceramic composite components fabricated by a forced-M technique are presented. Axial elastic modulus measurements on a number of tubes show that the Young`s modulus varies along the length of the tube, with occasional very stiff or very soft regions. Tests to failure on a few tubes show the initiation of non-linear stress-strain behavior to be in the range of 3-9 ksi, followed by extensive non-linear deformation up to failure. For one tube, the failure stress obtained was 20.1 ksi, but the strains to failure at various axial locations varies from 0.19%to 0.24%. The correlation between modulus and proportional limit is considered within the ACK matrix cracking theory and within a model in which matrix cracking between fiber tows occurs, both modified to account for matrix porosity. The crack size required to cause stress concentrations large enough to cause failure at the observed strength is considered. Predictions for both matrix cracking and strength suggest that the current generation of tubes are controlled by microstructural defects.

  19. Flaw Detection in Thin-Walled Tubes

    International Nuclear Information System (INIS)

    The author considers the special features and advantages of ultrasonic methods of detecting flaws in thin-walled tubes by means of Lamb's waves and describes the apparatus used. In addition to standard methods of inspecting and testing tubes, ultrasonics and eddy currents are now widely used in detecting concealed defects (fissures, non-metallic inclusions, foliation, blisters), deep notches, cracks and scratches on inner surfaces, determining grain size, and measuring wall thickness and corrosion depth. For the ultrasonic detection of flaws in thin-walled tubes using Lamb's waves one must work on the relatively flat parts of the dispersion curves. For example, greatest sensitivity to foliation during inspection by the reflection method is possessed by anti-symmetrical waves of the first and second modes. The author shows the effect of non-uniform thickness and ovalness of tubes on signal fluctuations in inspection by the shadow method. Metal structure is tested by the ''ratio'' method based on a comparison between signals of different frequency which are reflected by or which pass through the materials. In smooth and finned thin-walled tubes with diameters of 3 to 60 mm and wall thickness of 0.2 mm or more, made of stainless steel, high-nickel, zirconium, aluminium and other alloys, defects are detected with IDTs-3M, IDTs-5, UDT-4M, UKT-2 and other ultrasonic apparatus. Inspection is carried out by the immersion technique, the shadow method and the reflection method with working frequencies up to 10 MHz. Positive detection is achieved of defects over 0.5 mm in length and with a depth of 5% of the wall thickness. Grain size is controlled by USAD-61 structure analysers. Eddy-current apparatus is used for measuring the wall thickness of tubes made of non-magnetic materials. (author)

  20. Quarter-wave pulse tube

    Science.gov (United States)

    Swift, G. W.; Gardner, D. L.; Backhaus, S. N.

    2011-10-01

    In high-power pulse-tube refrigerators, the pulse tube itself can be very long without too much dissipation of acoustic power on its walls. The pressure amplitude, the volume-flow-rate amplitude, and the time phase between them evolve significantly along a pulse tube that is about a quarter-wavelength long. Proper choice of length and area makes the oscillations at the ambient end of the long pulse tube optimal for driving a second, smaller pulse-tube refrigerator, thereby utilizing the acoustic power that would typically have been dissipated in the first pulse-tube refrigerator's orifice. Experiments show that little heat is carried from the ambient heat exchanger to the cold heat exchanger in such a long pulse tube, even though the oscillations are turbulent and even when the tube is compactly coiled.

  1. Drift tubes of Linac 2

    CERN Multimedia

    Photographic Service

    1977-01-01

    Being redied for installation, those at the right are for tank 1, those on the left for tank 2. Contrary to Linac 1, which had drift-tubes supported on stems, here the tubes are suspended, for better mechanical stability.

  2. Laser welding of a tube

    International Nuclear Information System (INIS)

    For sleeving PWR steam generator tubes, the welding laser work is made under protection of a primary gas going out by the crossing window of the laser and under a secondary gas flowing axially through the head and the tube

  3. Tubing For Sampling Hydrazine Vapor

    Science.gov (United States)

    Travis, Josh; Taffe, Patricia S.; Rose-Pehrsson, Susan L.; Wyatt, Jeffrey R.

    1993-01-01

    Report evaluates flexible tubing used for transporting such hypergolic vapors as those of hydrazines for quantitative analysis. Describes experiments in which variety of tubing materials, chosen for their known compatibility with hydrazine, flexibility, and resistance to heat.

  4. Development and quality assessments of commercial heat production of ATF FeCrAl tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    Development and quality assessment of the 2nd generation ATF FeCrAl tube production with commercial manufacturers were conducted. The manufacturing partners include Sophisticated Alloys, Inc. (SAI), Butler, PA for FeCrAl alloy casting via vacuum induction melting, Oak Ridge National Laboratory (ORNL) for extrusion process to prepare the master bars/tubes to be tube-drawn, and Rhenium Alloys, Inc. (RAI), North Ridgeville, OH, for tube-drawing process. The masters bars have also been provided to Los Alamos National Laboratory (LANL) who works with Century Tubes, Inc., (CTI), San Diego, CA, as parallel tube production effort under the current program.

  5. Ultrasonic nondestructive tubing inspection system

    International Nuclear Information System (INIS)

    A system for measuring the extent of tube wall erosion in an inspection region of a heat exchanger tube of a nuclear steam generator, uses an ultrasonic means driven helically inside the eroded tube which may be filled with a fluid (e.g., water) to minimize ultrasonic wave attenuation. A control means cooperates with the ultrasonic means to produce a map of the tube wall thickness in an inspection region

  6. A performance evaluation system for photomultiplier tubes

    International Nuclear Information System (INIS)

    A comprehensive performance evaluation system for Photomultiplier tubes has been built up. The system is able to review diverse cathode and anode properties for PMTs with different sizes and dimensions. Relative and direct methods were developed for the quantum efficiency measurement and the results are consistent with each other. Two-dimensional and three-dimensional scanning platforms were built to test both the cathode and anode uniformity for either the plane type or spherical type photocathode. A Flash Analog-to-Digital Convertor module is utilized to achieve high speed waveforms sampling. The entire system is highly automatic and flexible. Details of the system and some typical experimental results are presented in this paper

  7. Automatic breast density classification using neural network

    International Nuclear Information System (INIS)

    According to studies, the risk of breast cancer directly associated with breast density. Many researches are done on automatic diagnosis of breast density using mammography. In the current study, artifacts of mammograms are removed by using image processing techniques and by using the method presented in this study, including the diagnosis of points of the pectoral muscle edges and estimating them using regression techniques, pectoral muscle is detected with high accuracy in mammography and breast tissue is fully automatically extracted. In order to classify mammography images into three categories: Fatty, Glandular, Dense, a feature based on difference of gray-levels of hard tissue and soft tissue in mammograms has been used addition to the statistical features and a neural network classifier with a hidden layer. Image database used in this research is the mini-MIAS database and the maximum accuracy of system in classifying images has been reported 97.66% with 8 hidden layers in neural network

  8. Automatic modulation recognition of communication signals

    CERN Document Server

    Azzouz, Elsayed Elsayed

    1996-01-01

    Automatic modulation recognition is a rapidly evolving area of signal analysis. In recent years, interest from the academic and military research institutes has focused around the research and development of modulation recognition algorithms. Any communication intelligence (COMINT) system comprises three main blocks: receiver front-end, modulation recogniser and output stage. Considerable work has been done in the area of receiver front-ends. The work at the output stage is concerned with information extraction, recording and exploitation and begins with signal demodulation, that requires accurate knowledge about the signal modulation type. There are, however, two main reasons for knowing the current modulation type of a signal; to preserve the signal information content and to decide upon the suitable counter action, such as jamming. Automatic Modulation Recognition of Communications Signals describes in depth this modulation recognition process. Drawing on several years of research, the authors provide a cr...

  9. Sleeve puller salvages welded tubes

    Science.gov (United States)

    Weaver, J. F.

    1980-01-01

    Tool removes sleeve remnants without distorting or damaging tubes, unlike pliers and other conventional handtools. Tubes can be reused, saving time, labor, and material in many applications. Sleeve-removal fixture consists of pressure screw, swing arm, locking screws, and base. It removes sleeve remnant from tubing after welded joint has been sawed through.

  10. Development and formability analysis of TRIP seamless steel tube

    Institute of Scientific and Technical Information of China (English)

    Zhang Zicheng; Zhu Fuxian

    2014-01-01

    In this paper,the production technology of transformation induced plasticity (TRIP) steel was first introduced into the steel tube manufacture field to produce the steel tubes with high strength and plasticity. The TRIP seamless steel tubes with the microstructure of ferrite,bainite,retained austenite and a little martensite were successfully fabricated using a cold-drawn steel tube with two-stage heat treatment technique and continu-ous heat treatment process,respectively. The ring tensile test and cold bend test were carried out to study the formability of the newly developed TRIP seamless steel tube. The results showed that the TRIP seamless steel tubes have a good cold formability,and they are available to be used in the tube hydroforming process. In ad-dition,the equipment of continuous heat treatment developed in the current study can be used to produce TRIP steel tube,and it may serve as an important reference for the industrial production of TRIP steel tube.

  11. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

    Directory of Open Access Journals (Sweden)

    Jean-Claude Mollet

    2013-03-01

    Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  12. Neural tube defects

    Directory of Open Access Journals (Sweden)

    M.E. Marshall

    1981-09-01

    Full Text Available Neural tube defects refer to any defect in the morphogenesis of the neural tube, the most common types being spina bifida and anencephaly. Spina bifida has been recognised in skeletons found in north-eastern Morocco and estimated to have an age of almost 12 000 years. It was also known to the ancient Greek and Arabian physicians who thought that the bony defect was due to the tumour. The term spina bifida was first used by Professor Nicolai Tulp of Amsterdam in 1652. Many other terms have been used to describe this defect, but spina bifida remains the most useful general term, as it describes the separation of the vertebral elements in the midline.

  13. Damping in heat exchanger tube bundles. A review

    International Nuclear Information System (INIS)

    Damping is a major concern in the design and operation of tube bundles with loosely supported tubes in baffles for process shell and tube heat exchangers and steam generators which are used in nuclear, process and power generation industries. System damping has a strong influence on the amplitude of vibration. Damping depends upon the mechanical properties of the tube material, geometry of intermediate supports and the physical properties of shell-side fluid. Type of tube motion, number of supports, tube frequency, vibration amplitude, tube mass or diameter, side loads, support thickness, higher modes, shell-side temperature etc., affect damping in tube bundles. The importance of damping is further highlighted due to current trend of larger exchangers with increased shell-side velocities in modern units. Various damping mechanisms have been identified (Friction damping, Viscous damping, Squeeze film damping, Support damping. Two-Phase damping, and very recent-Thermal damping), which affect the performance of process exchangers and steam generators with respect to flow induced vibration design, including standard design guidelines. Damping in two-phase flow is very complex and highly void fraction, and flow-regime dependent. The current paper focuses on the various known damping mechanisms subjected to both single and two-phase cross-flow in process heat exchangers and steam generators and formulates the design guidelines for safer design. (author)

  14. Wear on Plugged Tube due to the Foreign Objects on the Secondary Side of Steam Generator

    International Nuclear Information System (INIS)

    In this paper, the changes of the tube frequency and amplitude are introduced before and after plugging. The amplitude of the bottom span for the steam generator tube is not much changed after tube plugging. Moreover, the contact force between the plugged tube and the foreign object is the same as that of intact tube and the foreign object. However, the frequencies of plugged tubes are about 9∼12% higher than those of intact tubes. That means the wear due to the foreign object would be accelerated after the tube plugging. Therefore, the tube stabilizer should be installed when the tube is plugged due to the foreign object wear. The tube wall of steam generator is a pressure boundary between the coolant of the primary system and the feedwater of the secondary system. It is very important to insure the structural integrity of the tubes because the radioactive coolant is flow into the feedwater due to the pressure difference as the result of tube failure. The degradations of steam generator tubes are corrosion, wear, fatigue and foreign object wear, etc. The foreign object wear is one of mechanical degradation due to materials flew into the secondary side of steam generator. The steam generator tubes, estimated not to insure structural integrity from the results of the nondestructive evaluation such as eddy current test and visual inspection, are excluded from the service with plugging. However, the tube wear is still being progressed after the plugging because the relative motion between the tube and structure is still existed due to the secondary side flow in the steam generator. If the tube is completely cut because of the degradation, the tube can be a stress or of failure of tubes around the plugged tube. The contact force between the structure and tube is lowered as the wear is progressed. However, the contact force between the foreign object and tube is not changed as the wear is progressed. Therefore, the structural integrity of tubes around the foreign

  15. X-ray tubes

    International Nuclear Information System (INIS)

    An improved form of x-ray tube is described which consists of a rotatable anode disc and an electron beam source enclosed in an envelope. The beam of electrons strikes the edge of the anode disc at an acute angle, producing x-rays which are transmitted through a window in the envelope. To improve performance and life of the anode disc it is additionally reciprocated back and forth along its axis of rotation. Dimensions are specified. (U.K.)

  16. Primary fallopian tube carcinoma

    Directory of Open Access Journals (Sweden)

    Mladenović-Segedi Ljiljana

    2009-01-01

    Full Text Available Introduction. Primary fallopian tube carcinoma is extremely rare, making 0.3-1.6% of all female genital tract malignancies. Although the etymology of this tumor is unknown, it is suggested to be associated with chronic tubal inflammation, infertility, tuberculous salpingitis and tubal endometriosis. High parity is considered to be protective. Cytogenetic studies show the disease to be associated with over expression of p53, HER2/neu and c-myb. There is also some evidence that BRCA1 and BRCA2 mutations have a role in umorogeneis. Clinical features. The most prevailing symptoms with fallopian tube carcinoma are abdominal pain, abnormal vaginal discharge/bleeding and the most common finding is an adnexal mass. In many patients, fallopian tube carcinoma is asymptomatic. Diagnosis. Due to its rarity, preoperative diagnosis of primary fallopian tube carcinoma is rarely made. It is usually misdiagnosed as ovarian carcinoma, tuboovarian abscess or ectopic pregnancy. Sonographic features of the tumor are non-specific and include the presence of a fluid-filled adnexal structure with a significant solid component, a sausage-shaped mass, a cystic mass with papillary projections within, a cystic mass with cog wheel appearance and an ovoid-shaped structure containing an incomplete separation and a highly vascular solid nodule. More than 80% of patients have elevated pretreatment serum CA-125 levels, which is useful in follow-up after the definite treatment. Treatment. The treatment approach is similar to that of ovarian carcinoma, and includes total abdominal hysterectomy and bilateral salpingo-oophorectomy. Staging is followed with chemotherapy.

  17. Making automatic differentiation truly automatic : coupling PETSc with ADIC

    International Nuclear Information System (INIS)

    Despite its name, automatic differentiation (AD) is often far from an automatic process. often one must specify independent and dependent variables, indicate the derivative quantities to be computed, and perhaps even provide information about the structure of the Jacobians or Hessians being computed. However, when AD is used in conjunction with a toolkit with well-defined interfaces, many of these issues do not arise. They describe recent research into coupling the ADIC automatic differentiation tool with PETSc, a toolkit for the parallel numerical solution of PDEs. This research leverages the interfaces and objects of PETSc to make the AD process very nearly transparent

  18. Investigating the Relationship between Stable Personality Characteristics and Automatic Imitation.

    Directory of Open Access Journals (Sweden)

    Emily E Butler

    Full Text Available Automatic imitation is a cornerstone of nonverbal communication that fosters rapport between interaction partners. Recent research has suggested that stable dimensions of personality are antecedents to automatic imitation, but the empirical evidence linking imitation with personality traits is restricted to a few studies with modest sample sizes. Additionally, atypical imitation has been documented in autism spectrum disorders and schizophrenia, but the mechanisms underpinning these behavioural profiles remain unclear. Using a larger sample than prior studies (N=243, the current study tested whether performance on a computer-based automatic imitation task could be predicted by personality traits associated with social behaviour (extraversion and agreeableness and with disorders of social cognition (autistic-like and schizotypal traits. Further personality traits (narcissism and empathy were assessed in a subsample of participants (N=57. Multiple regression analyses showed that personality measures did not predict automatic imitation. In addition, using a similar analytical approach to prior studies, no differences in imitation performance emerged when only the highest and lowest 20 participants on each trait variable were compared. These data weaken support for the view that stable personality traits are antecedents to automatic imitation and that neural mechanisms thought to support automatic imitation, such as the mirror neuron system, are dysfunctional in autism spectrum disorders or schizophrenia. In sum, the impact that personality variables have on automatic imitation is less universal than initial reports suggest.

  19. Fabrication of seamless calandria tubes

    International Nuclear Information System (INIS)

    Full text: Calandria tube is a large diameter, thin walled zircaloy-4 tube and is an important structural component of PHWR type of reactors. These tubes are lifetime components and remain during the full life of the reactor. Calandria tubes are classified as extremely thin walled tubes with a diameter to wall thickness ratio of around 96. Such thin walled tubes are conventionally produced by seam welded route comprising of extrusion of slabs followed by a series of hot and rolling passes, shaping into O-shape and eventual welding. An alternative and superior method of fabricating the calandria tubes, the seamless route, has been developed, which involves hot extrusion of mother blanks followed by three successive cold pilger reductions. Eccentricity correction of the extruded blanks is carried out on a special purpose grinding equipment to bring the wall thickness variation within permissible limits. Predominant wall thickness reductions are given during cold pilgering to ensure high Q-factor values. The texture in the finished tubes could be closely, controlled with an average fr value of 0.65. Pilgering parameters and tube guiding system have been specially designed to facilities rolling of thin walled tubes. Seamless calandria tubes have distinct advantages over welded tubes. In addition to the absence of weld, they are dimensionally more stable, lighter in weight and possess uniform grains with superior grain size. The cycle time from billet to finished product is substantially reduced and the product is amenable to high level of quality assurance. The most significant feature of the seamless route is its material recovery over welded route. Residual stresses measured in the tubes indicate that these are negligible and uniform along the length of the tube. In view of their superior quality, the first charge of seamless calandria tubes will be rolled into the first 500 MWe Pressurised Heavy Water Reactor at Tarapur

  20. Clogging of feeding tubes.

    Science.gov (United States)

    Marcuard, S P; Perkins, A M

    1988-01-01

    This is a report of an in vitro study evaluating clotting ability of some formulas with intact protein and hydrolyzed protein sources in a series of buffers ranging from a pH of 1 thru 10. The following 10 products were tested: Ensure Plus, Ensure, Enrich, Osmolite, Pulmocare, Citrotein, Resource, Vivonex TEN, Vital, and Hepatic Acid II. Protein (10 and 20 g/liter) was added to Citrotein and Ensure Plus. All formulas were tested at full and some at half strength. Clotting occurred only in premixed intact protein formulas (Pulmocare, Ensure Plus, Osmolite, Enrich, Ensure) and in Resource. No clotting was observed for Citrotein (intact protein formula in powder form), Vital, Vivonex TEN, and Hepatic Aid II. Adding protein did not cause or increase clotting. In summary, clotting of some liquid formula diet appears to be an important factor causing possible gastric feeding tube occlusion. The following measures may help in preventing this problem: flushing before and after aspirating for gastric residuals to eliminate acid precipitation of formula in the feeding tube, advance the nasogastric feeding tube into the duodenum if possible, and avoid mixing these products with liquid medications having a pH value of 5.0 or less. PMID:3138452

  1. Traveling-Wave Tubes

    Science.gov (United States)

    Kory, Carol L.

    1998-01-01

    The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

  2. YouTube advertising and its significance in the Czech Republic

    OpenAIRE

    Borýsek, Jan

    2014-01-01

    This bachelor's thesis is dealing with current possibilities of advertising on YouTube in the Czech Republic. Based on the analysis of selected advertising campaigns on YouTube it evaluates its effectiveness and impact. By author's own research it identifies internet users' attitude towards advertising on YouTube in comparison with television advertising. The thesis also compares selected media indicators of YouTube and television.

  3. CRL X-RAY TUBE

    OpenAIRE

    Kolchevsky, N. N.; Petrov, P. V.

    2015-01-01

    A novel types of X-ray tubes with refractive lenses are proposed. CRL-R X-ray tube consists of Compound Refractive Lens- CRL and Reflection X-ray tube. CRL acts as X-ray window. CRL-T X-ray consists of CRL and Transmission X-ray tube. CRL acts as target for electron beam. CRL refractive lens acts as filter, collimator, waveguide and focusing lens. Properties and construction of the CRL X-ray tube are discussed.

  4. Spectrometer beam tube dimensional optimization

    International Nuclear Information System (INIS)

    This project examined the optimization of the design of a beam tube. An ANSYS model was used to find the minimum tube thickness and the best camber in a beam tube under vacuum and preloaded by a pair of magnet poles. After the tube was modeled one version of it was built for use in the accelerator. This beam tube was put under a vacuum and the dimensional changes were recorded and compared to the ANSYS predictions. These deflection results were quite close to the predicted numbers and would suggest that the stresses are similar to the predictions as well

  5. Industrial mastering the use of tube fining by high-frequency welding for gasproof boilers

    International Nuclear Information System (INIS)

    Results of introduction of 20 and 12Kh1MF steel tube fining by high-frequency welding are presented. Heat treatment effect on properties of joints is studied, mechanical tests, metallographical and electron-microscopic investigations are carried out. It is shown that weld method of fins to tubes with the help of high-frequency currents is characterized by universality that permits to produce fined tubes of practically any diameter with fins of any width, control of smooth tubes before the fins welding to them being provided. Studies of properties of fined tubes has shown high quality of welded joints carried out by high-frequency current heating

  6. Automatic Kurdish Dialects Identification

    Directory of Open Access Journals (Sweden)

    Hossein Hassani

    2016-02-01

    Full Text Available Automatic dialect identification is a necessary Lan guage Technology for processing multi- dialect languages in which the dialects are linguis tically far from each other. Particularly, this becomes crucial where the dialects are mutually uni ntelligible. Therefore, to perform computational activities on these languages, the sy stem needs to identify the dialect that is the subject of the process. Kurdish language encompasse s various dialects. It is written using several different scripts. The language lacks of a standard orthography. This situation makes the Kurdish dialectal identification more interesti ng and required, both form the research and from the application perspectives. In this research , we have applied a classification method, based on supervised machine learning, to identify t he dialects of the Kurdish texts. The research has focused on two widely spoken and most dominant Kurdish dialects, namely, Kurmanji and Sorani. The approach could be applied to the other Kurdish dialects as well. The method is also applicable to the languages which are similar to Ku rdish in their dialectal diversity and differences.

  7. Wet channel measurement of pressure tube to calandria tube spacing in CANDU reactors

    International Nuclear Information System (INIS)

    The pressure tube (PT) to calandria tube (CT) spacing in CANDU reactors is an important parameter that relates to the general condition of the fuel channels. The measurement system that was developed to measure this parameter during the wet channel inspections of Pickering Units 1 and 2 is described in this paper. A send-receive eddy current probe was designed which is primarily sensitive to variations in PT/CT spacing but is also affected by pressure tube wall thickness. A computer simulation showed that the phase angles of the response to these variables are similar for all usable frequencies, thus eliminating the possibility of multifrequency compensation. A marriage of technologies was proposed involving the ultrasonic measurement of wall thickness values which are then used to extract the spacing information from the eddy current signal. The accuracy of the system is approximately ±(30% +.1mm) which has been sufficient to determine if and where any of the pressure tubes have come in contact with their calandria tube. Field experience with the new system is discussed and areas for development are also outlined

  8. Reliability of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Kadokami, E. [Mitsubishi Heavy Industries Ltd., Hyogo-ku (Japan)

    1997-02-01

    The author presents results on studies made of the reliability of steam generator (SG) tubing. The basis for this work is that in Japan the issue of defects in SG tubing is addressed by the approach that any detected defect should be repaired, either by plugging the tube or sleeving it. However, this leaves open the issue that there is a detection limit in practice, and what is the effect of nondetectable cracks on the performance of tubing. These studies were commissioned to look at the safety issues involved in degraded SG tubing. The program has looked at a number of different issues. First was an assessment of the penetration and opening behavior of tube flaws due to internal pressure in the tubing. They have studied: penetration behavior of the tube flaws; primary water leakage from through-wall flaws; opening behavior of through-wall flaws. In addition they have looked at the question of the reliability of tubing with flaws during normal plant operation. Also there have been studies done on the consequences of tube rupture accidents on the integrity of neighboring tubes.

  9. Microdischarges in DC accelerator tubes

    International Nuclear Information System (INIS)

    Voltage tests on the Daresbury ceramic/titanium accelerator tube have shown that microdischarges play an important role in the conditioning process. It has been found that the voltage onset for microdischarges in a tube is dependent on the surface contamination of the electrodes and the tube geometry (in particular the tube length). This geometrical effect can be related to the trajectories of secondary ions emitted from the electrode surfaces. Sensitive diagnostic techniques have been developed to study the mass and energy distribution of ions emitted along the axis of the tube during these predischarges. The energy distribution of protons (and H- ions) can be related to the origins of the discharges in the tube. Detailed results are presented for a particular tube geometry. (author)

  10. The Caltech Tomography Database and Automatic Processing Pipeline.

    Science.gov (United States)

    Ding, H Jane; Oikonomou, Catherine M; Jensen, Grant J

    2015-11-01

    Here we describe the Caltech Tomography Database and automatic image processing pipeline, designed to process, store, display, and distribute electron tomographic data including tilt-series, sample information, data collection parameters, 3D reconstructions, correlated light microscope images, snapshots, segmentations, movies, and other associated files. Tilt-series are typically uploaded automatically during collection to a user's "Inbox" and processed automatically, but can also be entered and processed in batches via scripts or file-by-file through an internet interface. As with the video website YouTube, each tilt-series is represented on the browsing page with a link to the full record, a thumbnail image and a video icon that delivers a movie of the tomogram in a pop-out window. Annotation tools allow users to add notes and snapshots. The database is fully searchable, and sets of tilt-series can be selected and re-processed, edited, or downloaded to a personal workstation. The results of further processing and snapshots of key results can be recorded in the database, automatically linked to the appropriate tilt-series. While the database is password-protected for local browsing and searching, datasets can be made public and individual files can be shared with collaborators over the Internet. Together these tools facilitate high-throughput tomography work by both individuals and groups. PMID:26087141

  11. Ultrasonic inspection of tube to tube plate welds

    International Nuclear Information System (INIS)

    To monitor the deterioration of a weld between a tube and tube plate which has been repaired by a repair sleeve inside the tube and brazed at one end to the tube, ultrasound from a crystal at the end of a rod is launched, in the form of Lamb-type waves, into the tube through the braze and allowed to travel along the tube to the weld and be reflected back along the tube. The technique may also be used for the type of heat exchanger in which, during construction, the tubes are welded to the tube plate via external sleeves in which case the ultrasound is used in a similar manner to inspect the sleeve/tube plate weld. an electromagnetic transducer may be used to generate the ultrasound. The ultrasonic head comprising the crystal and an acoustic baffle is mounted on a Perspex (RTM) rod which may be rotated by a stepping motor. Echo signals from the region of deterioration may be isolated by use of a time gate in the receiver. The device primarily detects circumferentially orientated cracks, and may be used in heat exchangers in nuclear power plants. (author)

  12. Electronic amplifiers for automatic compensators

    CERN Document Server

    Polonnikov, D Ye

    1965-01-01

    Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as

  13. Template synthesized chitosan nano test tubes for drug delivery applications

    Science.gov (United States)

    Perry, Jillian L. Moulton

    There is tremendous current interest in developing nanoscale drug delivery vehicles. Though intensive efforts have focused on developing spherical drug delivery vehicles, cylindrically shaped vehicles such as nanotubes offer many advantages. Typically, nanotubes can carry a larger inner payload than nanoparticles of the same diameter. Also, we can prepare nanotubes in templates whose geometries can be controlled, in turn allowing precise control over the length and diameter of the tubes. In addition, template synthesized nanotubes can be differentially functionalized on the inner and outer surfaces. Furthermore, templates that are closed on one end can be used to fabricate nano test tubes (closed on one end). The geometry of these nano test tubes allows them to be easily filled with a payload, the open end sealed with a nanoparticle to protect the payload from leaking out, and then the exterior of the tube can be functionalized with a targeting moiety. In an effort to develop such a system, we explored the fabrication of chitosan nano test tubes. Defect-free, chitosan nano test tubes of uniform size were synthesized within the pores of a nanoporous alumina template membrane. While the nano test tubes remained within the template membrane, their inner cavities were filled with a model payload. The payload was then trapped inside the nano test tubes by sealing the open ends of the tubes with latex nanoparticle caps. For proof-of-principle studies, imine linkages were used to attach the caps to the nano test tubes. To create a self-disassembling system, disulfide chemistry was used to covalently cap the nano test tubes. Once removed from the template, the exterior of the nano test tubes were modified with a targeting moiety, allowing them to be targeted to pathological sites. We have also shown that the chitosan nano test tubes are biodegradable by two systems: enzymatic cleavage by lysozymes and disulfide cleavage of the crosslinker by reducing environments

  14. A Study on the Development of Ultrasonic Scanning Device for the Inspection and Evaluation of Creep Damage of HK - 40 Reformer Tube Welded Zone

    International Nuclear Information System (INIS)

    Detection of creep damages in centrifugally cast HK-40 reformer furnace catalyst tube is a common problem for the safety and scheduled operation of chemical plants. This study was focused on the development of an automatic ultrasonic scanning device with which the creep damage of welded zone of HK-40 reformer tubes is detected and evaluated

  15. Improved distribution using a fully automatic, extended apparatus

    International Nuclear Information System (INIS)

    For the separation of mixed rare earth (RE) nitrates by Craig-distribution between nitric acid and tri-n-butylphosphate an improved apparatus was used: 200 elements (tubes) and automatic operation instead of 160 elements and operation by hand. A comparison of the separation was made and the efficiency characterized by the practical separation coefficients βeff and the effective distribution number n. The new apparatus yielded a better separation of the same quantity of RE-nitrates or the same separation of a bigger quantity. The conditions seem especially apted for the separation of the heavier yttrium earths. (Authors)

  16. Application of hydrostatic extrusion to fabrication of zircaloy tubing

    International Nuclear Information System (INIS)

    Two approaches are presented to the fabrication of BWR Zircaloy cladding tubes: (7) replacing the final pass of the pilgering process with cold hydrostatic extrusion, and (2) application of hot hydrostatic extrusion to the manufacture of tube shells which are then processed by the conventional pilgering process. With the first approach, an extrusion ratio (ER) of 5 could be obtained, but it should be limited to a maximum of 3 to prevent the occurence of galling. The properties of the obtained tubes were nearly identical to those of the current BWR cladding tubes. Application of the second technique resulted in an increase of ER to three times that of the conventional direct extrusion. The tubing processed at higher ER showed higher strength and lower ductility in the tension tests but exhibited higher ductility in the burst tests. 5 refs

  17. Electrical conductivity channel for a shock tube

    Science.gov (United States)

    Lu, Frank K.; Liu, Hsuan-Cheng; Wilson, Donald R.

    2005-09-01

    The design of an electrical conductivity measurement channel for a shock tube is described. This measurement channel is used for the study of weakly ionized, high-enthalpy flows of gases seeded with alkali salts. The theory for determining the dimensions of the measurement channel and the electrical power supply for the channel is based on Ohm's law. Data are shown which demonstrate that the channel performs well. However, the measured electrical conductivity was one or two orders less than theoretical values. The current traces for each case show that the peak current occurred behind the contact surface, which indicates that some of the seed was entrained behind the test gas originally in the driven tube. An analysis of the effect of Joule heating on the measured conductivity was conducted. The result of increased temperature due to Joule heating in the measurement channel is believed to be minimal. Reasons for the discrepancy are given.

  18. Automatic Detection of Electric Power Troubles (ADEPT)

    Science.gov (United States)

    Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint; Brady, Mike; Ford, Donnie

    1988-01-01

    Automatic Detection of Electric Power Troubles (A DEPT) is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system. It is designed for two modes of operation: real time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a laser printer. This system consists of a simulated space station power module using direct-current power supplies for solar arrays on three power buses. For tests of the system's ablilty to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three buses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modeling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base.

  19. Development of an automatic reactor inspection system

    International Nuclear Information System (INIS)

    Using recent technologies on a mobile robot computer science, we developed an automatic inspection system for weld lines of the reactor vessel. The ultrasonic inspection of the reactor pressure vessel is currently performed by commercialized robot manipulators. Since, however, the conventional fixed type robot manipulator is very huge, heavy and expensive, it needs long inspection time and is hard to handle and maintain. In order to resolve these problems, we developed a new automatic inspection system using a small mobile robot crawling on the vertical wall of the reactor vessel. According to our conceptual design, we developed the reactor inspection system including an underwater inspection robot, a laser position control subsystem, an ultrasonic data acquisition/analysis subsystem and a main control subsystem. We successfully carried out underwater experiments on the reactor vessel mockup, and real reactor ready for Ulchine nuclear power plant unit 6 at Dusan Heavy Industry in Korea. After this project, we have a plan to commercialize our inspection system. Using this system, we can expect much reduction of the inspection time, performance enhancement, automatic management of inspection history, etc. In the economic point of view, we can also expect import substitution more than 4 million dollars. The established essential technologies for intelligent control and automation are expected to be synthetically applied to the automation of similar systems in nuclear power plants

  20. Steam generator tube inspection in Japan

    International Nuclear Information System (INIS)

    Steam generator tube inspection was first carried out in 1971 at Mihama Unit-1 that is first PWR plant in Japan, when the plant was brought into the first annual inspection. At that time, inspection was made on sampling basis, and only bobbin coil probe was used. After experiencing various kinds of tube degradations, inspection method was changed from sampling to all number of tubes, and various kinds of probes were used to get higher detectability of flaw. At present, it is required that all the tubes shall be inspected in their full length at each annual inspection using standard bobbin coil probe, and some special probes for certain plants that have susceptibility of occurrence of flaw. Sleeve repaired portion is included in this inspection. As a result of analyses of eddy current testing data, all indications that have been evaluated to be 20% wall thickness or deeper shall be repaired by either plugging or sleeving, where flaw morphology is to be a wastage or wear. Other types of flaw such as IGA/SCC are not allowed to be left inservice when those indications are detected. These inspections are performed according to inspection procedures that are approved by regulatory authority. Actual inspections are witnessed by the Japan Power engineering and inspection corporation (JAPEIC)'s inspectors during data acquisition and analysis, and they issue inspection report to authority for review and approval. It is achieved high safety performance of steam generator through this method of inspections, however. some tube leakage problems were experienced in the past. To prevent recurrence of such events, government is conducting development and verification test program for new eddy current testing technology