The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform

Stephen Hall - One of the best experts on this subject based on the ideXlab platform.

  • characterization of fluid flow in a shear band in porous rock using Neutron Radiography
    Geophysical Research Letters, 2013
    Co-Authors: Stephen Hall
    Abstract:

    The challenge of understanding how localized deformation modifies fluid flow in porous rock is addressed. New approaches are presented, based on Neutron Radiography and digital image analyses, to track fluid flow in rock specimens and to calculate flow velocity fields providing local flow measurements. The results show that Neutron Radiography, backed up by appropriate image analysis, is a very powerful tool in this context, being far more sensitive to the fluids in the rock than X-ray Radiography. Analysis of Neutron Radiography images of water imbibition into a laboratory-deformed sandstone specimen has provided new measurements of local fluid flow velocities within a shear band, indicating that flow is faster and water storage is higher in the band (attributed to higher capillary forces associated with damage). (Less)

Masahito Matsubayashi - One of the best experts on this subject based on the ideXlab platform.

  • An improved fast Neutron Radiography quantitative measurement method
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2004
    Co-Authors: Masahito Matsubayashi, Koji Yoshii, Takashi Hibiki, Kaichiro Mishima, Koji Okamoto
    Abstract:

    Abstract The validity of a fast Neutron Radiography quantification method, the Σ-scaling method, which was originally proposed for thermal Neutron Radiography was examined with Monte Carlo calculations and experiments conducted at the YAYOI fast Neutron source reactor. Water and copper were selected as comparative samples for a thermal Neutron Radiography case and a dense object, respectively. Although different characteristics on effective macroscopic cross-sections were implied by the simulation, the Σ-scaled experimental results with the fission Neutron spectrum cross-sections were well fitted to the measurements for both the water and copper samples. This indicates that the Σ-scaling method could be successfully adopted for quantitative measurements in fast Neutron Radiography.

  • Imaging of Rabbit VX-2 Hepatic Cancer by Cold and Thermal Neutron Radiography
    Japanese Journal of Applied Physics, 2003
    Co-Authors: Yoshinori Tsuchiya, Masahito Matsubayashi, Tohoru Takeda, Thet Thet Lwin, Jin Wu, Akio Yoneyama, Akira Matsumura, Tomiei Hori, Yuji Itai
    Abstract:

    Neutron Radiography is based on differences in Neutron mass attenuation coefficients among the elements and is a non-destructive imaging method. To investigate biomedical applications of Neutron Radiography, imaging of rabbit VX-2 liver cancer was performed using thermal and cold Neutron Radiography with a Neutron imaging plate. Hepatic vessels and VX-2 tumor were clearly observed by Neutron Radiography, especially by cold Neutron imaging. The image contrast of this modality was better than that of absorption-contrast X-ray Radiography.

  • Preliminary examination of the applicability of imaging plates to fast Neutron Radiography
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001
    Co-Authors: Masahito Matsubayashi, Koji Yoshii, Takashi Hibiki, Kaichiro Mishima, Koji Okamoto
    Abstract:

    Abstract Fast Neutron Radiography is an attractive non-destructive inspection technique because of the excellent penetration characteristics of fast Neutrons in matter. However, the difficulty of detecting fast Neutrons reduces this attractive feature. As an experiment to overcome the difficulty, imaging plates were applied to fast Neutron Radiography. A simple combination of two sheets of imaging plates and a sheet of polyethylene as a proton emitter was examined with the (fast Neutron, thermal Neutron and gamma ray) FTG discriminator proposed by Yoneda et al. . The experimental results showed that the method could be applicable to fast Neutron Radiography with effective discrimination of γ-rays

  • The review of the application of Neutron Radiography to thermal hydraulic research
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1999
    Co-Authors: Kaichiro Mishima, Takashi Hibiki, Yasushi Saito, Hideo Nakamura, Masahito Matsubayashi
    Abstract:

    Abstract This paper is concerned with the establishment of thermal Neutron Radiography as a high accuracy measurement method. This paper reviews the present status on the development of high-frame-rate Neutron Radiography with a steady thermal Neutron beam and its application to multiphase flow research performed at the Research Reactor Institute of Kyoto University in collaboration with the Japan Atomic Energy Research Institute.

  • Liquid metal flow measurement by Neutron Radiography
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1996
    Co-Authors: Nobuyuki Takenaka, Terushige Fujii, Hitoshi Asano, Masahito Matsubayashi, Yasunori Motomura, Akira Tsuruno
    Abstract:

    Abstract Visualization of a liquid metal flow and image processing methods to measure the vector field are carried out by real-time Neutron Radiography. The JRR-3M real-time thermal Neutron Radiography facility in the Japan Atomic Energy Research Institute was used. Lead—bismuth eutectic was used as a working fluid. Particles made from a gold—cadmium intermetallic compound (AuCd 3 ) were used as the tracer for the visualization. The flow vector field was obtained by image processing methods. It was shown that the liquid metal flow vector field was obtainable by real-time Neutron Radiography when the attenuation of Neutron rays due to the liquid metal was less than 1/e and the particle size of the tracer was larger than one image element size digitized for the image processing.

J.p. Barton - One of the best experts on this subject based on the ideXlab platform.

  • Filters For Thermal Neutron Radiography
    Nondestructive Testing and Evaluation, 2020
    Co-Authors: J.p. Barton
    Abstract:

    Abstract A comprehensive study of data helpful in the design of filters for thermal Neutron Radiography has been undertaken. Many existing or proposed facilities might benefit from optimization of ...

  • Multi-purpose Neutron Radiography system
    1996
    Co-Authors: J.p. Barton, L.e. Bryant, P. Berry
    Abstract:

    A conceptual design is given for a low cost, multipurpose Radiography system suited for the needs of the Los Alamos National Laboratory (LANL). The proposed Neutron source is californium-252. One purpose is to provide an in-house capability for occasional, reactor quality, Neutron Radiography thus replacing the recently closed Omega-West Reactor. A second purpose is to provide a highly reliable standby transportable Neutron Radiography system. A third purpose is to provide for transportable Neutron probe gamma spectroscopy techniques. The cost is minimized by shared use of an existing x-ray facility, and by use of an existing transport cask. The achievable Neutron Radiography and radioscopy performance characteristics have been verified. The demonstrated image qualities range from high resolution gadolinium - SR film, with L:D = 100:1, to radioscopy using a LIXI image with L:D = 30:1 and Neutron fluence 3.4 x 10{sup 5} n/cm{sup 2}.

  • ARG portable Neutron Radiography. Final report
    1995
    Co-Authors: J.p. Barton
    Abstract:

    In this report all available Neutron radiographic data, including results of tests run at LANL, McClellan AFB, and University of Virginia, will be combined to outline specific transportable Neutron Radiography systems that could achieve the desired results as a complement to x-Radiography capabilities for the Accident Response Group (ARG).

Peter Vontobel - One of the best experts on this subject based on the ideXlab platform.

  • Neutron Radiography a powerful method to determine time dependent moisture distributions in concrete
    Nuclear Engineering and Design, 2011
    Co-Authors: Peng Zhang, Tiejun Zhao, Folker H. Wittmann, E Lehmann, Peter Vontobel
    Abstract:

    Service life of reinforced concrete structures is often limited by penetration of water and compounds dissolved in water into concrete. Concrete can be damaged in this way and corrosion of steel reinforcement can be initiated. There is an urgent need to study water penetration into concrete in order to better understand deterioration mechanisms and to find appropriate ways to improve durability. Neutron Radiography provides us with an advanced non-destructive technique with high spatial resolution and extraordinary sensitivity. In this contribution, Neutron Radiography was successfully applied to study the process of water absorption of two types of concrete with different water–cement ratios, namely 0.4 and 0.6. The influence cracks and of water repellent treatment on water absorption has been studied on mortar specimens. It is possible to visualize migration of water into concrete and other cement-based composites and to quantify the time-dependent moisture distributions as function of time with high spatial resolution by means of Neutron Radiography. Water penetration depth obtained from Neutron Radiography is in good agreement with corresponding values obtained from capillary suction tests. Surface impregnation of concrete with silane prevents capillary uptake of water. Even fine cracks are immediately filled with water as soon as the surface gets in contact. Results provide us with a solid basis for a better understanding of deteriorating processes in concrete and other cement-based materials.

  • Application of Neutron Radiography to Observe Water Absorbtion of Concrete
    18th International Conference on Nuclear Engineering: Volume 3, 2010
    Co-Authors: Peng Zhang, Tiejun Zhao, L. S. Zhang, Folker H. Wittmann, Eberhard Lehmann, Peter Vontobel
    Abstract:

    It has been experienced that service life of reinforced concrete structures is often limited due to lack of durability of cement-based materials. One major reason for this durability problem is the penetration of water and compounds dissolved in water into concrete. Therefore, there is an urgent need to study water penetration into concrete in order to better understand deterioration mechanisms. Neutron Radiography provides an advanced non-destructive technique with high spatial resolution. In this contribution, Neutron Radiography was successfully utilized to study the process of water absorption of two types of concrete with different water-cement ratios namely 0.4 and 0.6. It is shown that it is possible to visualize migration of water into concrete and to quantify the time-dependent moisture distribution with accurately and with high spatial resolution by means of Neutron Radiography. In concrete with high water-cement ratio, water penetrates much quicker than in concrete with lower water cement ratio. Water penetration depth obtained from Neutron Radiography is in good agreement with corresponding values obtained from capillary suction tests. Experimental results obtained by means of Neutron Radiography on water penetration into concrete will be presented and discussed in this contribution. Results will provide us with a solid basis for a better understanding of deteriorating processes in concrete and other cement-based materials. These results may be considered to be a first step to improve durability of concrete.© 2010 ASME

  • scattering corrections in Neutron Radiography using point scattered functions
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2005
    Co-Authors: Nikolay Kardjilov, E Lehmann, F C De Beer, R Hassanein, Peter Vontobel
    Abstract:

    Scattered Neutrons cause distortions and blurring in Neutron Radiography pictures taken at small distances between the investigated object and the detector. This defines one of the most significant problems in quantitative Neutron Radiography. The quantification of strong scattering materials such as hydrogenous materials—water, oil, plastic, etc.—with a high precision is very difficult due to the scattering effect in the Radiography images. The scattering contribution in liquid test samples (H2O, D2O and a special type oil ISOPAR L) at different distances between the samples and the detector, the so-called Point Scattered Function (PScF), was calculated with the help of MCNP-4C Monte Carlo code. Corrections of real experimental data were performed using the calculated PScF. Some of the results as well as the correction algorithm will be presented.

  • Design and optimization of a CCD-Neutron Radiography detector
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2000
    Co-Authors: S Koerner, E Lehmann, Peter Vontobel
    Abstract:

    Radiography is a method to visualize the inner structure of macroscopic samples. It is based on the principle of the attenuation of radiation passing through matter, depending on the sample material and geometry. Besides the well-known radiographic examinations with X-rays and γ-rays, Neutron Radiography provides an important endorsement to radiographic examinations in the field of non-destructive testing (NDT), as contrary to X-rays, Neutrons are attenuated by some light materials, as hydrogen, boron and lithium but penetrate many heavy materials. Neutrons are even able to distinguish between different isotopes and besides, Neutron Radiography is an important tool for the investigation of radioactive materials. One of the key components of a Radiography facility is the detector. Usually, it is a two-dimensional, integrating imaging device. For Neutron Radiography applications requiring high quantitative precision as well as for Neutron tomography investigations, a CCD-camera-based Neutron Radiography detector has been developed. It consists of a Neutron sensitive scintillator screen, a nitrogen-cooled slow-scan CCD-camera and a mirror to reflect the light emitted by the scintillator to the CCD-camera. The whole assembly is placed in a light–tight enclosure. This paper presents the basic principle of this detector system, the strategy for the selection of the individual detector components, comparisons of the influence of the use of different components on the properties of the whole imaging device and results of the first test measurements.

Edwin P Chan - One of the best experts on this subject based on the ideXlab platform.

  • studying water and solute transport through desalination membranes via Neutron Radiography
    Journal of Membrane Science, 2018
    Co-Authors: Devin L Shaffer, David L. Jacobson, Jacob M Lamanna, Daniel S Hussey, Menachem Elimelech, Edwin P Chan
    Abstract:

    Abstract Neutron Radiography, a non-destructive imaging technique, is applied to study water and solute transport through desalination membranes. Specifically, we use Neutron Radiography to quantify lithium chloride draw solute concentrations across a thin-film composite membrane during forward osmosis permeation. This measurement provides direct visual confirmation of incomplete support layer wetting and reveals significant dilutive external concentration polarization of the draw solution outside of the membrane support layer. These transport-limiting phenomena have been hypothesized in previous work and are not accounted for in the standard thin-film model of forward osmosis permeation, resulting in inaccurate estimations of membrane transport properties. Our work demonstrates Neutron Radiography as a powerful measurement tool for studying membrane transport and emphasizes the need for direct experimental measurements to refine the forward osmosis transport model.