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Sample records for cr-39 plastic track

  1. CR-39 plastic nuclear track detector and its application in nuclear science

    International Nuclear Information System (INIS)

    Zhai Pengji; Tang Xiaowei; Wang Long; Liang Tianjiao

    2000-01-01

    The transparent and stable plastic material CR-39 can be used as a nuclear track detector which is highly sensitive to charged particles. It can record tracks induced by protons , alphas, fission fragments and other charged particles. Among various available solid state nuclear track detectors CR-39 has the lowest deposited energy density detection-threshold. The response of CR-39 to charged particles and the response curve of υ T of different charged particles to REL are given. The CR-39 detector is widely used in studies of nuclear reactions, angular distributions and reaction cross-sections caused by neutrons and charged particles. Neutron spectra, over a wide energy range, can be measured by the combination of CR-39 and a transformation screen. The successful applications of CR-39 in alpha particle dosimetry, environmental science (especially in the measurement of radon) and in biomedicine, such as the analysis of alpha radioactivity in sections of organic tissues, are described

  2. Automated counting and analysis of etched tracks in CR-39 plastic

    International Nuclear Information System (INIS)

    Majborn, B.

    1986-01-01

    An image analysis system has been set up which is capable of automated counting and analysis of etched nuclear particle tracks in plastic. The system is composed of an optical microscope, CCD camera, frame grabber, personal computer, monitor, and printer. The frame grabber acquires and displays images at video rate. It has a spatial resolution of 512 x 512 pixels with 8 bits of digitisation corresponding to 256 grey levels. The software has been developed for general image processing and adapted for the present purpose. Comparisons of automated and visual microscope counting of tracks in chemically etched CR-39 detectors are presented with emphasis on results of interest for practical radon measurements or neutron dosimetry, e.g. calibration factors, background track densities and variations in background. (author)

  3. Note: Application of CR-39 plastic nuclear track detectors for quality assurance of mixed oxide fuel pellets

    Science.gov (United States)

    Kodaira, S.; Kurano, M.; Hosogane, T.; Ishikawa, F.; Kageyama, T.; Sato, M.; Kayano, M.; Yasuda, N.

    2015-05-01

    A CR-39 plastic nuclear track detector was used for quality assurance of mixed oxide fuel pellets for next-generation nuclear power plants. Plutonium (Pu) spot sizes and concentrations in the pellets are significant parameters for safe use in the plants. We developed an automatic Pu detection system based on dense α-radiation tracks in the CR-39 detectors. This system would greatly improve image processing time and measurement accuracy, and will be a powerful tool for rapid pellet quality assurance screening.

  4. Effect of various etching conditions on the response of Cr-39 plastic track detector applied for radon dosimetry in environment

    International Nuclear Information System (INIS)

    Maged, A.F.; Ashraf, F.A.

    1997-01-01

    A solid state nuclear track detector Cr-39 has been used for measuring the radon concentration in the soil air and indoor concentration. The bulk etch rate, C B of Cr-39 has been measured in various concentrations of NaOH in the range (6-8 mole) at temperature 70 degree C. In addition, the track etch rate, V T , and the ratio V = V T /V B , of alpha particles emitted from radon gas exists in nature have been measured in a similar range of etching conditions. This study shows that 8 M NaOH at 70 degree C represent the optimum etching conditions for Cr-39, with the range of the present study. The equilibrium factor and gamma-dose equivalent were calculated by using the track densities of open and filtered solid state nuclear track detectors

  5. (1068 MeV) pi bar induced fission in gold observed with CR-39 plastic track detectors

    International Nuclear Information System (INIS)

    Javed, M.T.; Ahmad, S.M.; Shahzad, M.I.; Qureshi, I.E.; Sher, G.; Niazi, M.I.K.; Khan, H.A.

    1998-01-01

    In this paper results of the study of (1068 MeV) negative pion induced fission in a gold have been presented. To detect the reaction products emitted in the forward as well as backward hemisphere, a 4 pi configuration of exposure geometry was made by sandwiching the target material (gold) between two pieces of CR-39 plastic track detectors. This target-detector assembly was exposed at normal incidence to (1068 MeV) pi having a fluence of 8.55 x 10/sup 8/ pions/cm/sup 2/ at Low Energy Pion (LEP) channel of Clinton P. Anderson Meson Physics Facility (LAMPF), Brookhaven National Laboratory, USA. After exposure the gold layer was removed using aqua regia and then both the detectors were etched in 6N NaOH at (70 -+ 1) deg. C for 25 minutes to reveal the tracks. The number of fission fragment tracks in both the detectors were counted. The number of fission tracks in the detector placed downstream of the incident pion beam were found to be greater than those in the detector placed upstream. This difference has been attributed to the transfer of momentum in the forward direction due to the impact of pions. Reaction cross section has been calculated by taking into account the track statistics of both the detectors. (authors)

  6. Assessment of radiation shielding materials for protection of space crews using CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    DeWitt, J.M.; Benton, E.R.; Uchihori, Y.; Yasuda, N.; Benton, E.V.; Frank, A.L.

    2009-01-01

    A significant obstacle to long duration human space exploration such as the establishment of a permanent base on the surface of the Moon or a human mission to Mars is the risk posed by prolonged exposure to space radiation. In order to keep mission costs at acceptable levels while simultaneously minimizing the risk from radiation to space crew health and safety, a judicious use of optimized shielding materials will be required. We have undertaken a comprehensive study using CR-39 plastic nuclear track detector (PNTD) to characterize the radiation shielding properties of a range of materials-both common baseline materials such as Al and polyethylene, and novel multifunctional materials such as carbon composites-at heavy ion accelerators. The study consists of analyzing CR-39 PNTD exposed in front of and behind shielding targets of varying composition and at a number of depths (target thicknesses) relevant to the development and testing of materials for space radiation shielding. Most targets consist of 10 cm x 10 cm slabs of solid materials ranging in thickness from 1 to >30 g/cm 2 . Exposures have been made to beams of C, O, Ne, Si, Ar, and Fe at energies ranging from 290 MeV/amu to 1 GeV/amu at the National Institute of Radiological Sciences HIMAC and the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory. Analysis of the exposed detectors yields LET spectrum, dose, and dose equivalent as functions of target depth and composition, and incident heavy ion charge, energy, and fluence. Efforts are currently underway to properly weigh and combine these results into a single quantitative estimate of a material's ability to shield space crews from the interplanetary galactic cosmic ray flux.

  7. Measurement of target fragments produced by 160 MeV proton beam in aluminum and polyethylene with CR-39 plastic nuclear track detectors

    Czech Academy of Sciences Publication Activity Database

    Ambrožová, Iva; Yasuda, N.; Kodaira, S.; Sihver, L.

    2014-01-01

    Roč. 64, MAY (2014), s. 29-34 ISSN 1350-4487 R&D Projects: GA AV ČR KJB100480901; GA AV ČR IAA100480902; GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : target fragments * high-energy protons * Aluminium * Polyethylene * plastic nuclear track detectors * CR-39 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.213, year: 2014

  8. Characterization of plastic nuclear track detectors on solid state, CR-39 and LR-115 and its possibilities application on thermal and fast neutron dosimetry

    International Nuclear Information System (INIS)

    Vallejo Delgado, L.R.

    1989-01-01

    This work is an study about the use feasibility of plastic nuclear track detectors, LR 115, II-B (of Eastmann Kodak Co) and CR-39 (of American Acrylics and Plastics), for thermal and fast neutron dosimetry, respectively. The LR-115 with converter (n, alpha) was exposed to thermal neutrons with energy of 0,046 e V, proceeding from nuclear reactor RECH-1 of Nuclear Energy Chilean Commission. The irradiated films were submited to a chemical etching with NaOH, plus a washing and brushing. The CR-39 with polyethylene irradiator, was exposed to fast neutrons proceeding of calibrated sources of Am-Se. The irradiated plates were submited to a chemical pre-etching with KOH and a electrochemical post-etching. (author)

  9. Measurement of indoor radon concentration by CR-39 track detector

    International Nuclear Information System (INIS)

    Yamamoto, Masayoshi; Yoneda, Shigeru; Nakanishi, Takashi.

    1990-01-01

    A convenient and cheap method for measuring indoor radon ( 222 Rn) concentration with a CR-39 track detector is described. The detector consisted of two sheets of CR-39 enclosed separately in two plastic pots : one covered by a filter (cup method) and another no covering (bare method). The bare method was used here to supplement the cup method. To compare with the result of the CR-39 detector, alpha-ray spectrometry was carried out with a Si(Au) detector in a controlled radon exposure chamber. Indoor radon concentration measured in 133 houses in several districts of Ishikawa Prefecture have been found to range from 6 Bq/m 3 to as high as 113 Bq/m 3 with a median value of 24 Bq/m 3 . The problems to measure indoor radon concentration using the CR-39 detector are also discussed with emphasis on the position of setting the detector in the room and the possible thoron contribution to the detector. (author)

  10. CR-39 as induced track detector in reactor: irradiation effect

    International Nuclear Information System (INIS)

    Zylberberg, H.

    1989-07-01

    A systematic study about reactor's neutrons radiation effect and gamma radiation effect on the properties of CR-39 that are significant for its use as induced fission track detector is showed. The following studies deserved attention: kinetics of the fission track chemical development; efficiency to register and to develop fission track; losses of developable tracks; variation in the number of developable tracks and variation in the visible and ultraviolet radiation spectrum. The dissertation is organized in seven specific chapters: solid state nuclear tracks (SSNT); CR-39 as SSNT; objectives and problems presentation; preparation and characterization of CR-39 as SSNT; gamma irradiation effect on the properties of CR-39 as SSNT; reactor neutron irradiation effect on the properties of CR-39 as SSNT and, results discussions and conclusions. The main work contributions are the use of CR-39 in the determination of fissionable nuclide as thorium and uranium in solid and liquid samples; gamma radiation damage on CR-39 as well as the reactor's neutron damage on CR-39. (B.C.A.) 62 refs, 53 figs, 21 tabs

  11. Alpha particle track coloration in CR-39: Improved observability

    CERN Document Server

    Oezguemues, A

    1999-01-01

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger fi...

  12. Enhancement of Particle Track Etch Rate in CR-39 by UV Exposure

    Science.gov (United States)

    Wiesner, Micah; Ume, Rubab; McLean, James; Sangster, Craig; Regan, Sean

    2015-11-01

    The use of CR-39 plastic as a Solid State Nuclear Track Detector is effective for obtaining data in high-energy particle experiments including inertial confinement fusion. To reveal particle tracks after irradiation, CR-39 is chemically etched at elevated temperatures with NaOH, producing signal pits at the nuclear track sites that are measurable by an optical microscope. CR-39 pieces sometimes also exhibit etch-induced noise, either surface features not caused by nuclear particles. When CR-39 is exposed to high intensity UV light after nuclear irradiation with 5.4 MeV alpha particles and before etching, an increase in etch rates and pit diameters is observed, though UV exposure can also increase noise. We have determined that light from a low pressure mercury vapor lamp (predominantly wavelength 253.7 nm) increases etch rates and pit diameters while causing minimal background noise. Heating CR-39 to elevated temperatures (~80 °C) during UV exposure also improves the signal-to-noise ratio for this process. Surprisingly, initial data from CR-39 irradiated with 3.4 MeV protons and exposed to UV show reduced pit diameters. This material is based in part upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  13. A CR-39 track dosemeter for routine individual neutron monitoring

    International Nuclear Information System (INIS)

    Luszik-Bhadra, M.; Alberts, W.G.; Dietz, E.; Guldbakke, S.; Matzke, M.; d'Errico, F.

    1994-01-01

    A personal neutron dosemeter for routine individual monitoring is proposed. It is based on a CR-39 track detector covered on three separate areas by converters with different boron contents and inserted into a commercial TLD albedo dosemeter capsule. The dose readings from three areas of the electrochemically etched CR-39 detector are combined to yield a dose equivalent response which is almost independent of the incident neutron energy in the range from thermal neutrons up to 20 MeV. In addition, the dose contributions of thermal, intermediate and fast neutrons can be determined separately. Unlike the TLD albedo dosemeter, which in general requires prior in-field calibration and whose use is then restricted to that field, this dosemeter can be used in neutron fields without any knowledge of the spectral distribution with the same calibration factor. The angular dependence of the dosemeter's response has been measured and compared with that of the directional dose equivalent H'(10). The lower limit of detection is 0.15 mSv. It is possible to obtain an independent, second dose reading from the same Cr-39 detector for neutron energies above 100 keV. The dosemeter has also been successfully tested for use in accident dosimetry applying chemical etching and an optical density reading of the CR-39 detector. (author)

  14. A simple apparatus for quick qualitative analysis of CR39 nuclear track detectorsa)

    Science.gov (United States)

    Gautier, D. C.; Kline, J. L.; Flippo, K. A.; Gaillard, S. A.; Letzring, S. A.; Hegelich, B. M.

    2008-10-01

    Quantifying the ion pits in Columbia Resin 39 (CR39) nuclear track detector from Thomson parabolas is a time consuming and tedious process using conventional microscope based techniques. A simple inventive apparatus for fast screening and qualitative analysis of CR39 detectors has been developed, enabling efficient selection of data for a more detailed analysis. The system consists simply of a green He-Ne laser and a high-resolution digital single-lens reflex camera. The laser illuminates the edge of the CR39 at grazing incidence and couples into the plastic, acting as a light pipe. Subsequently, the laser illuminates all ion tracks on the surface. A high-resolution digital camera is used to photograph the scattered light from the ion tracks, enabling one to quickly determine charge states and energies measured by the Thomson parabola.

  15. Measurements of radon in dwellings with CR-39 track detectors

    DEFF Research Database (Denmark)

    Majborn, Benny

    1986-01-01

    A passive integrating dosemeter has been designed for measuring natural radiation in dwellings. The dosemeter contains one or two CR-39 track detectors to measure radon and three thermoluminescence dosemeters to measure external radiation. The dosemeter was investigated in a pilot study in 1983....../84, and it is now used in a nationwide survey of natural radiation in Danish dwellings. The characteristics of the dosemeter with respect to radon measurements are presented, and the radon monitoring results obtained in the pilot study are summarized...

  16. A parameterization of nuclear track profiles in CR-39 detector

    Science.gov (United States)

    Azooz, A. A.; Al-Nia'emi, S. H.; Al-Jubbori, M. A.

    2012-11-01

    In this work, the empirical parameterization describing the alpha particles’ track depth in CR-39 detectors is extended to describe longitudinal track profiles against etching time for protons and alpha particles. MATLAB based software is developed for this purpose. The software calculates and plots the depth, diameter, range, residual range, saturation time, and etch rate versus etching time. The software predictions are compared with other experimental data and with results of calculations using the original software, TRACK_TEST, developed for alpha track calculations. The software related to this work is freely downloadable and performs calculations for protons in addition to alpha particles. Program summary Program title: CR39 Catalog identifier: AENA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENA_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Copyright (c) 2011, Aasim Azooz Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met • Redistributions of source code must retain the above copyright, this list of conditions and the following disclaimer. • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution This software is provided by the copyright holders and contributors “as is” and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the copyright owner or contributors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and

  17. Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

    CERN Document Server

    Yasuda, N; Amemiya, K; Takahashi, H; Kyan, A; Ogura, K

    1999-01-01

    Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.

  18. The response of CR-39 nuclear track detector to 1-9 MeV protons

    International Nuclear Information System (INIS)

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Gatu Johnson, M.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2011-01-01

    The response of CR-39 nuclear track detector (TasTrak) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. Effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.

  19. CR-39 track detector for multi-MeV ion spectroscopy.

    Science.gov (United States)

    Jeong, T W; Singh, P K; Scullion, C; Ahmed, H; Hadjisolomou, P; Jeon, C; Yun, H; Kakolee, K F; Borghesi, M; Ter-Avetisyan, S

    2017-05-19

    We present the characteristics of track formation on the front and rear surfaces of CR-39 produced by laser-driven protons and carbon ions. A methodological approach, based on bulk etch length, is proposed to uniquely characterize the particle tracks in CR-39, enabling comparative description of the track characteristics in different experiments. The response of CR-39 to ions is studied based on the energy dependent growth rate of the track diameter to understand the intrinsic particle stopping process within the material. A large non-uniformity in the track diameter is observed for CR-39 with thickness matching with the stopping range of particles. Simulation and experimental results show the imprint of longitudinal range straggling for energetic protons. Moreover, by exploiting the energy dependence of the track diameter, the energy resolution (δE/E) of CR-39 for few MeV protons and Carbon ion is found to be about 3%.

  20. Autoradiographic measurement of low concentrations of alpha-active nuclides using CR-39 track detectors

    International Nuclear Information System (INIS)

    Freyer, K.; Dietze, K.; Weisse, S.; Kummer, G.

    1991-01-01

    An autoradiographic method for the determination of alpha emission rates from plastic packaging materials for VLSI silicon memory devices based on long-time exposure of the samples on CR-39 detectors has been tested. The lower limit of detection will be strongly influenced by the background of the detector material and amounts at times to 0.002 alpha particles cm -2 h -1 after 200 days exposure. A mathematical method for the interpretation of very low track densities is discussed. The first results of its application are presented. (author)

  1. Charge identification in CR-39 nuclear track detector using relativistic lead ion fragmentation

    CERN Document Server

    Manzoor, S; Rana, M A; Shahzad, M I; Sher, G; Sajid, M; Khan, H A; Giacomelli, G; Giorgini, M; Mandrioli, G; Patrizii, L; Popa, V; Serra, P; Togo, V

    2000-01-01

    Three stacks of plastic CR-39 Nuclear Track Detectors (NTD) were exposed to 158 A GeV /sup 207/Pb ions at the CERN-SPS beam facility. The main purpose of this experiment was the calibration of the CR-39 for the search of atmospheric magnetic monopoles. Different targets (Al, Cu and Pb) were used to produce a large spectrum of charge ions for the purpose of calibration as well as the study of ultrarelativistic lead ion fragmentation. The exposure of each stack was performed at normal incidence with a fluence of about 1500 ion/cm /sup 2/. The total number of lead ions in each spill was about 7.8*10 /sup 4/ and there were eight spills incident on each stack. For the stack with the Cu target, the lengths of etched cones on one face of the CR-39 were measured. From this measurement procedure, a new calibration curve has been generated for the extended charge region 63or=2, and a large dynamical range in counting rates of up to 10/sup 9/ s/sup -1/ due to single particle or current readout, respectively. (2 refs).

  2. Track etch parameters and annealing kinetics assessment of protons of low energy in CR-39 detector

    International Nuclear Information System (INIS)

    Jain, R.K.; Kumar, Ashok; Singh, B.K.

    2012-01-01

    Highlights: ► We calibrate CR-39 detector with very low energy protons. ► We establish linear relationship between track diameter and time/energy up to 200 keV. ► We determine activation energy of annealing using different models. ► We justify concept of single annealing activation energy in CR-39. - Abstract: In this paper threshold of the registration sensitivity of very low energy proton in CR-39 is investigated. Irradiation of CR-39 (poly-allyl-diglycol carbonate) was carried out with very low energy mono energetic protons of 20–60 keV from a mini proton accelerator. Nearly 10 4 /cm 2 fluence of protons was used. The variation of track diameter with etching time as well as proton energy response curve was carefully calibrated. The bulk and track etch rates were measured by using proton track diameters. Bulk etch rate was also measured by the thickness of removed surface layer. The thermal annealing of proton track at temperatures ranging from 100 to 200 °C in CR-39 was studied by several models. Activation energy of annealed CR-39 detectors was calculated by slope of track etch rate and temperature plot. The data of proton tracks of 200, 250 and 300 keV from 400 kV Van-de-Graaff accelerator was also used and compared with the track diameters of different energies of proton.

  3. CR-39 polymer, a promising new solid state track recorder for high energy neutron applications

    International Nuclear Information System (INIS)

    Ruddy, F.H.; Preston, C.C.; Gold, R.; Benton, E.V.; Roberts, J.H.

    1980-01-01

    CR-39 Polymer, a new solid state track recorder with unprecedented sensitivity to lightly ionizing particles (such as protons) is being developed for eventual neutron dosimetry applications in the Fusion Materials Irradiation Test Facility and elsewhere. The diameters of proton tracks have been found to vary smoothly and reproducibly as a function of energy from 0.20 to 18.0 MeV. Preliminary results on the response of CR-39 polymer to proton tracks as a function of angle show a rapid decrease of the registration efficiency from 100% to 0 for angles of incidence less than 75 0 . Proton recoil track size distributions in CR-39 polymer irradiated with monoenergetic neutrons of varying energy are presented. Some proposed high energy neutron dosimetry and radiography systems using CR-39 polymer are discussed

  4. Change of Cr-39(DOP) track detector response as a result of space exposure

    International Nuclear Information System (INIS)

    Yadav, J.S.; Singh, R.K.

    1990-01-01

    The response functions for CR-39(DOP) plastic track detectors are calculated, using the simplex method for nonlinear least squares fit, from experimental data obtained from accelerator beams as well as space exposure. The average detector sensitivity is reduced by over 30% in the case of space exposure. The average charge shift for the oxygen group is one charge unit, and it increases with particle charge. The effect decreases with restricted energy loss, which is contrary to that observed in the registration temperature effect. We have discussed various environmental parameters which may produce the observed effect. The registration temperature effect may account for the observed effect (within the errors) for the worst case (temperature) analysis. However, a more reasonable estimate suggests that both the registration temperature as well as pressure during exposure contribute to the observed effect. To discriminate between the separate contributions, further experimental data is needed. (author)

  5. Comparison of SEM and Optical Analysis of DT Neutron Tracks in CR-39 Detectors

    Energy Technology Data Exchange (ETDEWEB)

    P.A. Mosier-Boss, L.P.G. Forsley, P. Carbonnelle, M.S. Morey, J.R. Tinsley, J. P. Hurley, F.E. Gordon

    2012-01-01

    A solid state nuclear track detector, CR-39, was exposed to DT neutrons. After etching, the resultant tracks were analyzed using both an optical microscope and a scanning electron microscope (SEM). In this communication, both methods of analyzing DT neutron tracks are discussed.

  6. Particularization of alpha contamination using CR-39 track detectors

    Indian Academy of Sciences (India)

    each was sandwiched to be dried in desiccant paper. To obtain the track diameter distribution and track density, the etched detec- tors were read and measured using an automatic digital image analysis system. (LEICA), consisting of a DMRE optical microscope with 600× magnification, a. Pramana – J. Phys., Vol. 69, No.

  7. Particularization of alpha contamination using CR-39 track detectors

    Indian Academy of Sciences (India)

    parameters of etched alpha tracks measured under the microscope [1–4]. Solid state nuclear track detectors (SSNTDs) have been the subject of immense commercial and scientific interest. Since their discovery, SSNTDs have been inves- tigated by numerous researchers in a wide variety of applications [5]. On the other.

  8. Comparison of SEM and Optical Analysis of DT Neutron Tracks in CR-39 Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mosier-Boss, P A; Carbonelle, P; Morey, M S; Tinsley, J R; Hurley, J P

    2012-01-01

    CR-39 detectors were exposed to DT neutrons generated by a Thermo Fisher model A290 neutron generator. Afterwards, the etched tracks were examined both optically and by SEM. The purpose of the analysis was to compare the two techniques and to determine whether additional information on track geometry could be obtained by SEM analysis. The use of these techniques to examine triple tracks, diagnostic of ≥9.6 MeV neutrons, observed in CR-39 used in Pd/D codeposition experiments will also be discussed.

  9. Particularization of alpha contamination using CR-39 track detectors

    Indian Academy of Sciences (India)

    Solid-state nuclear track detectors have found wide use in various domains of science and technology, e.g. in environmental experiments. The measurement of alpha activity on sources in an environment, such as air is not easy because of short penetration range of alpha particles. Furthermore, measurement of alpha ...

  10. Triton, deuteron and proton responses of the CR-39 track detector

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Tomoya; Matsumoto, Hiroyoshi; Oda, Keiji [Kobe Univ. of Mercantile Marine (Japan)

    1996-07-01

    In the present study, we assessed the response of the CR-39 detector to proton, deuteron and triton from their etch-pit growth curves obtained by multi-step etching technique and the difference among their track registration properties was discussed. In order to avoid incorrect evaluation due to the missing track effect, particle irradiation was performed at various incident energies. The response function, S(R), etch rate ratio, S, as a function of the residual range, R, was experimentally evaluated for all hydrogen isotopes by this method. In the next, we obtained another form of response functions of S(E), S({beta}) and S(LET{sub 200}), which were presented as functions of the particle energy, E, the particle velocity, {beta}(=v/c), and the linear energy transfer in the case where the cut-off energy is 200 eV, LET{sub 200}, respectively. These information will be useful also in understanding the fundamentals of the latent track formation mechanism in the plastic track detectors. (J.P.N.)

  11. Calculation of depleted uranium concentration in dental fillings samples using the nuclear track detector CR-39

    International Nuclear Information System (INIS)

    Mahdi, K. H.; Subhi, A. T.; Tawfiq, N. F.

    2012-12-01

    The purpose of this study is to determine the concentration of depleted uranium in dental fillings samples, which were obtained some hospital and dental office, sale of materials deployed in Iraq. 8 samples were examined from two different fillings and lead-filling (amalgam) and composite filling (plastic). concentrations of depleted uranium were determined in these samples using a nuclear track detector CR-39 through the recording of the tracks left by of fragments of fission resulting from the reaction 2 38U (n, f). The samples are bombarded by neutrons emitted from the neutron source (2 41A m-Be) with flux of ( 10 5 n. cm- 2. s -1 ). The period of etching to show the track of fission fragments is 5 hours using NaOH solution with normalization (6.25N), and temperature (60 o C ). Concentration of depleted uranium were calculated by comparison with standard samples. The result that obtained showed that the value of the weighted average for concentration of uranium in the samples fillings (5.54± 1.05) ppm lead to thr filling (amalgam) and (5.33±0.6) ppm of the filling composite (plastic). The hazard- index, the absorbed dose and the effective dose for these concentration were determined. The obtained results of the effective dose for each of the surface of the bone and skin (as the areas most affected by this compensation industrial) is (0.56 mSv / y) for the batting lead (amalgam) and (0.54 mSv / y) for the filling composite (plastic). From the results of study it was that the highest rate is the effective dose to a specimen amalgam filling (0.68 mSv / y) which is less than the allowable limit for exposure of the general people set the World Health Organization (WHO), a (1 mSv / y). (Author)

  12. Calibrations of CR39 and Makrofol nuclear track detectors and search for exotic particles

    CERN Document Server

    Ambrosio, M; Auriemma, G; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Caruso, R; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; De Marzo, C; De Mitri, I; De Vincenzi, M; Dekhissi, H; Derkaoui, J; Di Credico, A; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Guarino, F; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Iarocci, E; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kumar, A; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longley, N P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Matteuzzi, D; Mazziotta, M N; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R; 10.1016/S0920-5632(03)02249-7

    2003-01-01

    We present the final results of the search for exotic massive particles in the cosmic radiation performed with the MACRO underground experiment. Magnetic monopoles and nuclearites flux upper limits obtained with the CR39 nuclear track subdetector, the scintillation and streamer tube subdetectors are given. Searches at high altitude with the SLIM experiment are in progress.

  13. Study of the characteristics of ionizing particles record of CR-39 track detectors

    International Nuclear Information System (INIS)

    Brandao, Luis Eduardo Barreira

    1983-01-01

    The bulk and track etching proprieties of a new Solid State Nuclear Track Detector CR-39 were investigated under different etching conditions. The discussion is based on results obtained using aqueous solutions of KOH with addition of alcoholic solvent to aqueous solutions. It was found that track registration sensitivity can be dramatically changed by using the proper chemical treatment. A method to enlarge and dye etch tracks to be viewed by simple projection on a screen is discussed. The applications of CR-39 in neutron fluence measurements are shown. Graphs are presented of the densities of the registered traces by the detector as a function of etch time both for samples with and without a polycarbonate radiator. (author)

  14. A study of CR-39 track response to charged particles from NOVA implosions

    International Nuclear Information System (INIS)

    Phillips, T.W.; Cable, M.D.; Hicks, D.G.; Li, C.K.; Petrasso, R.D.; Seguin, F.H.

    1996-01-01

    We have exposed CR-39 track recording material to a number of NOVA implosions. Radiation from the implosion passed through an array of ranging filters, which aided identification of the incident particles and their energies. The etching procedure was calibrated by including a piece of track exposed to DD protons from a small accelerator. For the same shots, we quantitatively compare the DD neutron yield with the DD proton yield determined from the track. In DT implosions, tracks produced by neutron interactions prevent observation of charged-particle tracks that are produced by the processes of knock-on, secondary or tertiary fusion

  15. Use of Image Pro Plus for counting of α particles tracks in CR-39

    International Nuclear Information System (INIS)

    Miranda, Marcia Valeria F.E. Sa; Crispim, Verginia Reis

    2011-01-01

    This paper measured the radon radiations present in NORM samples, through the diffusion chambers which contained a nuclear track detector (CR-39). For automatic counting of those tracks the computer program Image Pro plus was used. This paper reports the application of Image Pro plus for counting the nuclear tracks, coming from the radon radiation present in NORM samples. As the radiation rate of 222 Rn if proportional to the number of these tracks, the methodology allowed to compare the levels of contamination of the analysed samples. Also, tables and graphics are presented with counting results referring to the stage of validation of Image Pro plus

  16. Angular and dose dependence of CR-39 neutron response for shape-selected tracks

    CERN Document Server

    Tam, N C; Lakosi, L

    1999-01-01

    A shape selection method corresponding to an energy discrimination was used to eliminate unwanted events disturbing evaluation of CR-39 detectors in detecting tracks induced by particles both of perpendicular and oblique incidence. The angular dependence of the response was examined, detecting fast neutrons from sup 2 sup 5 sup 2 Cf with shape selection technique at various angles and distances. Also, the CR-39 track detectors with the sup 2 sup 5 sup 2 Cf source were exposed to high gamma-intensity of a sup 6 sup 0 Co irradiation facility in the range 0.1 to 4.5 kGy, similar to the exposures inside spent fuel assemblies. Using the two functions the lower limit of burnup could be determined by the method.

  17. Fast neutron dosimetry using CR-39 track detectors with polyethylene as radiator

    International Nuclear Information System (INIS)

    Castillo, F.; Espinosa, G.; Golzarri, J.I.; Osorio, D.; Rangel, J.; Reyes, P.G.; Herrera, J.J.E.

    2013-01-01

    The chemical etching parameters (etching time, temperature, normality of etchant, etc.) for the use of CR-39 (allyl diglycol carbonate – Lantrack ® ) as a fast neutron dosimeter have been optimized. The CR-39 chips, placed under a 1.5 mm polyethylene radiator, were exposed for calibration to an 241 Am-Be source at different time intervals for a given neutron fluence. After several chemical etching processes of the detectors with different conditions, the optimum characteristics for the chemical etching were found at 6N KOH solution, 60 ± 1 °C, for 12 h. An accurate relationship between the dose and fluence calculations was obtained as a function of the track density. - Highlights: ► Optimum etching time for fast neutron irradiated CR-39 track detectors is found. ► Relationship between dose and fluence obtained as a function of the track density. ► Results are consistent with those reported elsewhere, and extend the dose range

  18. An automatic device for counting a large number of tracks in CR39

    International Nuclear Information System (INIS)

    Venuti, G.C.; Casaccia, R.; Grisanti, G.; Risica, S.; Laakso, I.; Votano, L.

    1984-01-01

    In order to perform an indoor survey of internal exposure to radon and its short life daughters using track etching passive detectors, it is necessary to analyze a large amount of information without spending a lot of time and manual work. For this purpose, the possibility of utilizing PEPR (Precision Encoding and Pattern Recognition) normally used in the digitization of low energy particle tracks recorded on Bubble Chamber film has been studied. A special subroutine has been set up for a PDP 11/45 Computer to guide PEPR in studying the tracks of α-particles in CR39. (author)

  19. Bulk etching characteristics of CR-39 track detectors in hydroxide solutions

    International Nuclear Information System (INIS)

    Fonseca, E.S. da; Knoefel, T.M.J.; Tavares, O.A.P.

    1983-01-01

    A systematic study of the bulk etch rate of CR-39 track detectors in KOH and NaOH aqueous solutions is presented. A number of unirradiated and non-thermally treated CR-39 samples were chemically attacked in KOH and NaOH solutions of concentration and temperature in the range 2-10 N and 50-90 0 C, respectively. From measurements of the thickness of layers removed as a function of the etching time, the bulk etch rate υ β and the induction time T ο for surface removal were obtained for each etching condition. For both NaOH and KOH solution the activation energy of the process was derived as E = 0.76 ± 0.05 eV. It was observed that the induction time decreases both with increasing normality and temperature of the solution. (author) [pt

  20. A study of CR-39 plastic charged-particle detector replacement by consumer imaging sensors

    Energy Technology Data Exchange (ETDEWEB)

    Plaud-Ramos, K. O.; Freeman, M. S.; Wei, W.; Guardincerri, E.; Bacon, J. D.; Cowan, J.; Durham, J. M.; Huang, D.; Gao, J.; Hoffbauer, M. A.; Morley, D. J.; Morris, C. L.; Poulson, D. C.; Wang, Zhehui, E-mail: zwang@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-11-15

    Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a {sup 90}Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics. Noise reduction in CIS is nevertheless important for the indirect approach.

  1. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jobouri, Hussain A., E-mail: hahmed54@gmail.com; Rajab, Mustafa Y., E-mail: mostafaheete@gmail.com [Department of Physics, College of Science, AL-Nahrain University, Baghdad (Iraq)

    2016-03-25

    CR-39 detector which covered with boric acid (H{sub 3}Bo{sub 3}) pellet was irradiated by thermal neutrons from ({sup 241}Am - {sup 9}Be) source with activity 12Ci and neutron flux 10{sup 5} n. cm{sup −2}. s{sup −1}. The irradiation times -T{sub D} for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C° temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -T{sub D} has behavior linear relationships with following nuclear track parameters: i) total track number - N{sub T} ii) maximum track number - MRD (relative to track diameter - D{sub T}) at response region range 2.5 µm to 4 µm iii) maximum track number - M{sub D} (without depending on track diameter - D{sub T}). (b) The irradiation time -T{sub D} has behavior logarithmic relationship with maximum track number - M{sub A} (without depending on track area - A{sub T}). The image processing technique principally track diameter - D{sub T} can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  2. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  3. High energy charged particle registration in CR-39 polycarbonated detector

    International Nuclear Information System (INIS)

    Abdel-Wahab, M.S.; El Enany, N.; El Fiki, S.; Eissa, H.M.; El-Adl, E.H.; El-Feky, M.A.

    1991-01-01

    Track etch rate characteristics of CR-39 plastic detector exposed to 28 Si ions of 670 MeV energy have been investigated. Experimental results were obtained in terms of frequency distribution of the track diameter, track density and bulk etching rate. A dependence of the mean track diameter on energy was found. The application of the radiation effect of heavy ions on CR-39 in the field of radiation detection and dosimetry are discussed. Results indicated that it is possible to produce etchable tracks of 28 Si in this energy range in CR-39. We also report the etching characteristics of these tracks in the CR-39 detector. (orig.) [de

  4. Study of the optical properties and the carbonaceous clusters in thermally-annealed CR-39 and Makrofol-E polymer-based solid-state nuclear track detectors

    International Nuclear Information System (INIS)

    El Ghazaly, M.

    2012-01-01

    The induced modifications in the optical properties of CR-39 and Makrofol-E polymer-based solid state nuclear track detectors were investigated after thermal annealing at a temperature of 200 .deg. C for different durations. The optical properties were studied using an UV-visible spectrophotometer. From the UV-visible spectra, the direct and the indirect optical band gaps, Urbach's energies, and the number of carbon atoms in a cluster were determined. The absorbance of CR-39 plastic detector was found to decrease with increasing annealing time while the absorbance of Makrofol-E decreased with increasing annealing time. The width of the tail of localized states in the band gap ΔE was evaluated with the Urbach method. The optical energy band gaps were obtained from the direct and the indirect allowed transitions in K-space. Both of the direct and the indirect band gaps of the annealed CR-39 detector decrease with increasing annealing time while in Makrofol-E, they decreased after an annealing time of 15 minute and then showed no remarkable changes for a prolonged annealing times. Urbach's energy decreased significantly for both CR-39 and Makrofol-E with increasing annealing time. The number of carbon atoms in a cluster increased in the CR-39 detector with increasing annealing time while it decreased with increasing annealing time for Makrofol-E. We may conclude that the CR-39 detector undergoes greater modifications than the Makrofol-E detector upon thermal annealing at 200 .deg. C. In conclusion, the induced modifications in the optical properties of CR-39 and Makrofol-E are correlated with the temperature and the duration of annealing.

  5. Development of neutron personnel monitoring system based on CR-39 solid state nuclear track detector

    International Nuclear Information System (INIS)

    Massand, O.P.; Kundu, H.K.; Marathe, P.K.; Supe, S.J.

    1990-01-01

    Personnel neutron monitoring aims at providing a method to evaluate the magnitude of the detrimental effects on the personnel exposed to neutrons. Neutron monitoring is done for a small though growing number of personnel working with neutrons in a wide range of situations. Over the years, many solid state nuclear track detectors (SSNTD) have been tried for neutron personnel monitoring. CR-39 SSNTD is a proton sensitive polymer and offers a lot of promise for neutron personnel monitoring due to its high sensitivity and lower energy threshold for neutron detection. This report presents the mechanism of track formation in this polymer, the development of this neutron personnel monitoring system in our laboratory, its various characteristics and its promise as a routine personnel neutron monitor. (author). 1 tab., 7 figs

  6. Nuclear tracks in CR-39 produced by carbon, oxygen, aluminium and titanium ions.

    Science.gov (United States)

    Rickards, J; Romo, V; Golzarri, J I; Espinosa, G

    2002-01-01

    This work describes the response of CR-39 (allyl diglycol polycarbonate) to different ions (C, O, Al and Ti) produced by the Instituto de Fisica 3 MV 9SDH-2 Pelletron accelerator and backscattered from a thin Au film on a C support. The ion energies were chosen in series such that the ranges of the different ions in the detector were 2, 3, 4, 5, 6, 7 and 8 microm respectively for each series. Once exposed, the detectors were etched with a solution of 6.25 M KOH at 60 degrees C, and the reading was carried out using a digital image analysis system. An analysis of the measured track diameters of all the types of ions indicates that, for a given range, track kinetics are independent of type of ion, energy and stopping power.

  7. Measurement of radon gas concentration in fertilizer samples by using nuclear track detector (CR-39)

    International Nuclear Information System (INIS)

    Karim, M.S.; Abbas, F.I.; Mnawer, E.M.; Abbas, K.H.

    2011-01-01

    In the present work, we have measured the radon gas concentration in ten fertilizers samples for three kinds { mixed fertilizer (M.F), triple super phosphate (T.S.P), single super phosphate (S.S.P) } by using alpha-emitters registrations which are emitted form radon gas in (CR-39) nuclear track detector.The results obtained have shown that the highest average radon gas concentration in fertilizer samples was found in triple super phosphate sample(T.S.P.), which was (177.5Bq/m 3 ) (Iran origin), while the lowest average radon gas concentration was found in single super phosphate (S.S.P.) sample, which was (72.2Bq/m 3 ) (Iraq origin).The present results show that the radon gas concentration in all fertilizers samples is below the allowed limit from (International Commission of Radiation Protection) (ICRP) agency

  8. Radon measurements with CR-39 track detectors at specific locations in Turkey

    Directory of Open Access Journals (Sweden)

    Ulug Asiye

    2004-01-01

    Full Text Available Indoor radon concentration levels at three sites in Turkey were measured using CR-39 solid state nuclear track detectors. The annual mean of radon concentration was estimated on the basis of four quarter measurements at specific locations in Turkey. The measuring sites are on the active faults. The results of radon measurements are based on 280 measurements in doors. The annual arithmetic means of radon concentrations at three sites (Isparta Egirdir, and Yalvac were found to be 164 Bqm–3, 124 Bqm–3, and 112 Bqm–3 respectively, ranging from 78 Bqm–3 to 279 Bqm–3. The in door radon concentrations were investigated with respect to the ventilation conditions and the age of buildings. The ventilation conditions were determined to be the main factor affecting the in door radon concentrations. The in door radon concentrations in the new buildings were higher than ones found in the old buildings.

  9. New approach of modeling charged particles track development in CR-39 detectors

    International Nuclear Information System (INIS)

    Azooz, A.A.; Hermsdorf, D.; Al-Jubbori, M.A.

    2013-01-01

    In this work, previous modeling of protons and alpha particles track length development in CR-39 solid state nuclear track detectors SSNTD is modified and further extended. The extension involved the accommodation of heavier ions into the model. These ions include deuteron, lithium, boron, carbon, nitrogen and oxygen ions. The new modeling does not contain any case sensitive free fitting parameters. Model calculation results are found to be in good agreement with both experimental data and SRIM software range energy dependence predictions. The access to a single unified and differentiable track length development equation results in the ability to obtain direct results for track etching rates. - Highlights: • New modeling of ions track length evolution measured by different authors. • Ions considered are p, d, α, Li, B, C, N, O. • Equations obtained to describe L(t) and etch rate for all ions at wide energy range. • Equations obtained do not involve any free fitting parameters. • Ions range values obtained compare well with results of SRIM software

  10. Polymerization, structure and track recording properties of CR-39 cured with UV photoinitiators

    International Nuclear Information System (INIS)

    Stejny, J.; Carrell, J.; Palmer, M.J.

    2000-01-01

    CR-39 monomer was cured isothermally at temperatures from 54.5 to 115 deg. C with UV sensitive photoinitiators to high conversions. The use of photoinitiators allowed the cure of CR-39 isothermally at high temperatures and eliminated the danger of thermal runaway present in the conventionally used thermal initiation with peroxides. It was found that the properties of the UV photoinitiated CR-39 were similar to the conventionally polymerized resin

  11. Comparison of Pd/D co-deposition and DT neutron generated triple tracks observed in CR-39 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mosier-Boss, P. A.; Dea, J. Y.; Forsley, L. P. G.; Morey, M. S.; Tinsley, J. R.; Hurley, J. P.; Gordon, F. E.

    2010-08-01

    Solid state nuclear track detectors (SSNTDs), such as CR-39, have been used to detect energetic charged particles and neutrons. Of the neutron and charged particle interactions that can occur in CR-39, the one that is the most easily identifiable is the carbon breakup reaction. The observation of a triple track, which appears as three alpha particle tracks breaking away from a center point, is diagnostic of the 12C(n, n')3α carbon breakup reaction. Such triple tracks have been observed in CR-39 detectors that have been used in Pd/D co-deposition experiments. In this communication, triple tracks in CR-39 detectors observed in Pd/D co-deposition experiments are compared with those generated upon exposure to a DT neutron source. It was found that both sets of tracks were indistinguishable. Both symmetric and asymmetric tracks were observed. Using linear energy transfer (LET) curves and track modeling, the energy of the neutron that created the triple track can be estimated.

  12. Comparison of Pd/D co-deposition and DT neutron generated triple tracks observed in CR-39 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mosier-Boss, P.A.; Dea, J.Y. [SPAWAR Systems Center Pacific, San Diego, CA (United States); Forsley, L.P.G. [JWK International Corp., Annandale, VA (United States); Morey, M.S.; Tinsley, J.R.; Hurley, J.P. [National Security Technologies, LLC, Special Technologies Laboratory, Santa Barbara, CA (United States); Gordon, F.E. [SPAWAR Systems Center Pacific, Retired, San Diego, CA (United States)

    2010-08-15

    Solid state nuclear track detectors (SSNTDs), such as Columbia Resin 39 (CR-39), have been used to detect energetic charged particles and neutrons. Of the neutron and charged particle interactions that can occur in CR-39, the one that is the most easily identifiable is the carbon breakup reaction. The observation of a triple track, which appears as three alpha particle tracks breaking away from a center point, is diagnostic of the {sup 12}C(n, n')3{alpha} carbon breakup reaction. Such triple tracks have been observed in CR-39 detectors that have been used in Pd/D co-deposition experiments. In this communication, triple tracks in CR-39 detectors observed in Pd/D co-deposition experiments are compared with those generated upon exposure to a DT neutron source. It was found that both sets of tracks were indistinguishable. Both symmetric and asymmetric tracks were observed. Using linear energy transfer (LET) curves and track modeling, the energy of the neutron that created the triple track can be estimated. (authors)

  13. Impact of x-ray dose on track formation and data analysis for CR-39-based proton diagnostics

    International Nuclear Information System (INIS)

    Rinderknecht, H. G.; Rojas-Herrera, J.; Zylstra, A. B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Séguin, F. H.; Petrasso, R. D.; Filkins, T.; Steidle, Jessica A.; Traynor, N.; Freeman, C.; Steidle, Jeffrey A.

    2015-01-01

    The nuclear track detector CR-39 is used extensively for charged particle diagnosis, in particular proton spectroscopy, at inertial confinement fusion facilities. These detectors can absorb x-ray doses from the experiments in the order of 1–100 Gy, the effects of which are not accounted for in the previous detector calibrations. X-ray dose absorbed in the CR-39 has previously been shown to affect the track size of alpha particles in the detector, primarily due to a measured reduction in the material bulk etch rate [Rojas-Herrera et al., Rev. Sci. Instrum. 86, 033501 (2015)]. Similar to the previous findings for alpha particles, protons with energies in the range 0.5–9.1 MeV are shown to produce tracks that are systematically smaller as a function of the absorbed x-ray dose in the CR-39. The reduction of track size due to x-ray dose is found to diminish with time between exposure and etching if the CR-39 is stored at ambient temperature, and complete recovery is observed after two weeks. The impact of this effect on the analysis of data from existing CR-39-based proton diagnostics on OMEGA and the National Ignition Facility is evaluated and best practices are proposed for cases in which the effect of x rays is significant

  14. Uranium concentration in blood samples of Southern Iraqi leukemia patients using CR-39 track detector

    International Nuclear Information System (INIS)

    Al-Hamzawi, A.A.; Al-Qadisiyah University, Qadisiyah; Jaafar, M.S.; Tawfiq, N.F.

    2014-01-01

    The simple and effective technique of fission track etch has been applied to determine trace concentration of uranium in human blood samples taken from two groups of male and female participants: leukemia patients and healthy subjects group. The blood samples of leukemia patients and healthy subjects were collected from three key southern governorates namely, Basrah, Muthanna and Dhi-Qar. These governorates were the centers of intensive military activities during the 1991 and 2003 Gulf wars, and the discarded weapons are still lying around in these regions. CR-39 track detector was used for registration of induced fission tracks. The results show that the highest recorded uranium concentration in the blood samples of leukemia patients was 4.71 ppb (female, 45 years old, from Basrah) and the minimum concentration was 1.91 ppb (male, 3 years old, from Muthanna). For healthy group, the maximum uranium concentration was 2.15 ppb (female, 55 years old, from Basrah) and the minimum concentration was 0.86 ppb (male, 5 years old, from Dhi-Qar). It has been found that the uranium concentrations in human blood samples of leukemia patients are higher than those of the healthy group. These uranium concentrations in the leukemia patients group were significantly different (P < 0.001) from those in the healthy group. (author)

  15. Some characteristics of the CR-39 solid state nuclear - Track Detector for register of protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to registration properties of the CR-39 Solid State Nuclear Track Detector for charged particles are presented and discussed. The existence of an inverse proportion between the induction time and the temperature as well as normal concentration of solutions, is showed by the study of CR-39 chemical etching characteristics in NaOH and KOH solutions, comprising varied concentration and temperature. The bulk-etch rate and activation energy of the process were obtained. The critical energy and critical energy-loss rate of CR-39 track-detectors for registration of protons were experimentally determined. Samples were exposed to 24 Mev proton beams in the IEN/CNEN Cyclotron (CV-28), using scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples, in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy the critical energy was obtained. From the calculated energy-loss rate vs. energy curve, the critical energy loss rate were evaluated. The CR-39 response for low energy alpha particles (E = 7h) under the conditions of 6.25 N NaOH at 70 0 C. It is shown that successive chemical etchings do not produce the same track geometry as obtained by means of a continous revelation with the same total etching time. (Author) [pt

  16. An energy and direction independent fast neutron dosemeter based on electrochemically etched CR-39 nuclear track detectors

    International Nuclear Information System (INIS)

    James, K.; Matiullah; Durrani, S.A.

    1987-01-01

    A computer-based model is presented, which simulates the dose equivalent response of electrochemically etched CR-39 to fast neutrons of various energies and angles of incidence. Most previous calculations of the response of CR-39 have neglected the production of recoiling oxygen and carbon nuclei as well as α particles in the CR-39. We calculate that these 'heavy recoils' and α particles are the major source of electrochemically etchable tracks in bare CR-39 at neutron energies above approx. 2 MeV under typical etching conditions. Our calculations have been extended to predict the response of CR-39 used in conjunction with various combinations of polymeric front radiators and we have determined the radiator stack configuration with produces the most energy independent response. Again, the heavy recoils and α particles cannot be neglected and, for energies above approx. 2 MeV, these produce typically about 20% of the total response of our optimum stack. This type of fast neutron dosemeter is, however, strongly direction dependent. We have integrated the response over all appropriate angles to predict the dose equivalent response for two representative neutron fields, and we suggest a method for minimising the angular dependence. (author)

  17. Dose-equivalent response CR-39 track detector for personnel neutron dosimetry

    International Nuclear Information System (INIS)

    Oda, K.; Ito, M.; Yoneda, H.; Miyake, H.; Yamamoto, J.; Tsuruta, T.

    1991-01-01

    A dose-equivalent response detector based on CR-39 has been designed to be applied for personnel neutron dosimetry. The intrinsic detection efficiency of bare CR-39 was first evaluated from irradiation experiments with monoenergetic neutrons and theoretical calculations. In the second step, the radiator effect was investigated for the purpose of sensitization to fast neutrons. A two-layer radiator consisting of deuterized dotriacontane (C 32 D 66 ) and polyethylene (CH 2 ) was designed. Finally, we made the CR-39 detector sensitive to thermal neutrons by doping with orthocarbone (B 10 H 12 C 2 ), and also estimated the contribution of albedo neutrons. It was found that the new detector - boron-doped CR-39 with the two-layer radiator - would have a flat response with an error of about 70% in a wide energy region, ranging from thermal to 15 MeV. (orig.)

  18. A study on alpha particles range in Cr-39

    International Nuclear Information System (INIS)

    Ibrahim, Z.A.; Talaat, T.M.; Abdel-Aziz, Kh.M.A.; El-Asser, M.R.

    2000-01-01

    Cr-39 plastic nuclear track detector has been used in range determination of alpha particles. A set of experiments was carried out for studying alpha energy and track diameter relationships. This work was done under the optimum conditions of Cr-39 etching in 6.25 N NaOH at 70 degree C for various etching times. Determination of alpha range in Cr-39 recorders was studied at different energy values using the over etched track profile technique. Data are discussed within the framework of track formation theory in plastic foils, comparison between experimental and theoretical values of alpha range is included

  19. Ultraviolet radiation-induced modifications of the optical and registration properties of a CR-39 nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Saad, A.F., E-mail: abdallahsaad56@hotmail.com [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Al-Faitory, N.M. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Hussein, M. [Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Mohamed, R.A. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya)

    2015-09-15

    The UV–VIS (ultraviolet–visible) spectra and etching characteristics of poly allyl diglycol carbonate (PADC, a form of the CR-39 polymer) detector films after exposure to UV radiation for various times have been studied. Etching experiments were carried out on the UV-exposed CR-39 detectors after alpha particle and fission-fragment irradiation using a {sup 252}Cf source. The bulk and track etch rates were measured using the alpha and fission-fragment track diameters, and the sensitivity and the detection efficiency were also determined. The optical band gap for both indirect and direct transitions was calculated based on the absorption edge of the UV spectra of the pristine and variously UV-exposed detectors. The optical band gap evidently indicates a gradual change in the optical properties of the CR-39 detector that is induced by the UV radiation. This study shows that the UV-exposed CR-39 detectors were demonstrated to be highly sensitive to alpha particles, but proved to be somewhat less sensitive to the fission fragments.

  20. High-resolution nuclear track mapping in detailed cellular histology using CR-39 with the contact microscopy technique

    International Nuclear Information System (INIS)

    Amemiya, K.; Takahashi, H.; Kajimoto, Y.; Nakazawa, M.; Yanagie, H.; Hisa, T.; Eriguchi, M.; Nakagawa, Y.; Majima, T.; Kageji, T.; Sakurai, Y.; Kobayashi, T.; Konishi, T.; Hieda, K.; Yasuda, N.; Ogura, K.

    2005-01-01

    In radiation cancer therapies using energetic charged particles such as proton/heavy-ion therapy and boron neutron capture therapy (BNCT), studies on radiation-induced biological response at cellular level are important because the radiation damage from energetic charged particles is highly localized along their paths and the radiation sensitivity is quite different in each cellular organelle. In such studies the information on the position of charged particle impact in biological cells is necessary. A novel method for high-resolution nuclear track mapping in detailed cellular histology has been developed. In this technique, biological specimens mounted on CR-39 plates are exposed to energetic charged particles. The irradiated samples are exposed to UV, and then etched for a short time. Both etch pits of nuclear tracks and relief for transmission UV image of the specimen can be observed on the CR-39 surface with an atomic force microscope (AFM) at about 100 nm resolution

  1. Some characteristics of the CR-39 solid state nuclear-track detector for protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to certain registration properties of the CR-39 solid state nuclear-track detector for charged particles are presented and discussed. The determination of the CR-39 chemical etching in NaOH and KOH solutions, comprising concentration (2-10N) and temperature effects (50-90 0 C), showed the existence of an inverse proportion between the induction time and the temperature as well as the normal concentration of the solutions. The critical energy and the critical energy-loss rate of CR-39 track detectors for registration of protons were experimentally determined. A number of samples was exposed to 24MeV proton beams in the IEN-CNEN Cyclotron (CV-28), using a scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy for 16h and 24h chemical etching (6.25 NaOH, 70 0 C), and considering 1.5 μm as the minimum observable track-diameter, the values (21.0 + - 1.5) MeV and (22.5 + - 1.5) MeV were deduced, respectively, for the critical energy. From the calculated energy-loss rate versus energy curve, the critical energy-loss rate was evaluated as 24 + - 2 MeV.cm 2 /g. Finally, the CR-39 response for low energy alpha particles (E [pt

  2. Use of Image Pro Plus for counting of {alpha} particles tracks in CR-39; Uso do Image Pro Plus para contagem de tracos de particulas {alpha} em CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Marcia Valeria F.E. Sa [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Crispim, Verginia Reis [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Gomes, Rogerio dos S.; Gomes, Joana D' Arc R. Lopes, E-mail: mvaleria@cnen.gov.b, E-mail: verginia@con.ufrj.b, E-mail: rogeriog@cnen.gov.b, E-mail: jlopes@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2011-10-26

    This paper measured the radon radiations present in NORM samples, through the diffusion chambers which contained a nuclear track detector (CR-39). For automatic counting of those tracks the computer program Image Pro plus was used. This paper reports the application of Image Pro plus for counting the nuclear tracks, coming from the radon radiation present in NORM samples. As the radiation rate of {sup 222}Rn if proportional to the number of these tracks, the methodology allowed to compare the levels of contamination of the analysed samples. Also, tables and graphics are presented with counting results referring to the stage of validation of Image Pro plus

  3. Optimization of microwave-induced chemical etching for rapid development of neutron-induced recoil tracks in CR-39 detectors

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Tripathy, S.P.; Bandyopadhyay, T.

    2014-01-01

    A systematic investigation is carried out to optimize the recently established microwave-induced chemical etching (MICE) parameters for rapid development of neutron-induced recoil tracks in CR-39 detectors. Several combinations of all available microwave powers with different etching durations were analysed to determine the most suitable etching condition. The etching duration was found to reduce with increasing microwave power and the tracks were observed at about 18, 15, 12, and 6 min for 300, 450, 600 and 900 W of microwave powers respectively compared to a few hours in chemical etching (CE) method. However, for complete development of tracks the etching duration of 30, 40, 50 and 60 min were found to be suitable for the microwave powers of 900, 600, 450 and 300 W, respectively. Temperature profiles of the etchant for all the available microwave powers at different etching durations were generated to regulate the etching process in a controlled manner. The bulk etch rates at different microwave powers were determined by 2 methods, viz., gravimetric and removed thickness methods. A logarithmic expression was used to fit the variation of bulk etch rate with microwave power. Neutron detection efficiencies were obtained for all the cases and the results on track parameters obtained with MICE technique were compared with those obtained from another detector processed with chemical etching. - Highlights: • Microwave-induced chemical etching method is optimized for rapid development of recoil tracks due to neutrons in CR-39 detector. • Several combinations of microwave powers and etching durations are investigated to standardize the suitable etching condition. • Bulk-etch rates are determined for all microwave powers by two different methods, viz. gravimetric and removed thickness method. • The method is found to be simple, effective and much faster compared to conventional chemical etching

  4. Present status of fast neutron personnel dosimetry system based on CR-39 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Pal, Rupali; Sathian, Deepa; Jayalakshmi, V.; Bakshi, A.K.; Chougaonkar, M.P.; Mayya, Y.S.; Kumar, Valli; Babu, Rajesh; Kar, S.; Joshi, V.M.

    2011-08-01

    Neutron sources are of different types depending upon the method of production such as nuclear reactors, particle accelerators and laboratory sources. Neutron sources depending upon their energy, flux, size etc. are used for variety of applications in basic and applied sciences, neutron scattering experiments and in industry such as oil well - digging, coal mining and processing, ore processing etc. Personnel working in nuclear installations such as reactors, accelerators, spent fuel processing plants, nuclear fuel cycle operations and those working in various industries such as oil refining, oil well-digging, coal mining and processing, ore processing, etc. need to be monitored for neutron exposures, if any. Neutron monitoring is especially necessary in view of the fact that the radiation weighting factor for neutron is much higher than gamma rays and also it varies with energy. Radiological Physics and Advisory Division is involved in monitoring of personnel working in neutron fields. Around 2100 workers from 70 institutions (DAE and Non-DAE) are monitored on a quarterly basis. Neutron personnel monitoring, carried out in the country is based on Solid State Nuclear Track Detection (SSNTD) technique. In this technique, neutrons interact with hydrogen in CR-39 polymer to produce recoil protons. These protons create damages in the polymer, which are enlarged and appear as tracks when subjected to electrochemical etching (ECE). These tracks are counted in an optical system to evaluate the neutron dose. The neutron dosimetry system based on SSNTD has undergone a significant development, since it was started in 1990. The development includes upgradation of image analysis system for counting tracks, introduction of chemical etching (CE) at elevated temperatures for evaluation of dose equivalents above 10 mSv and use of carbon laser for cutting of CR-39 detectors. The entire dose evaluation process has been standardized, which includes calibration and performance tests

  5. Fast neutron personnel dosimetry by CR-39 plastics a new electrochemical etching procedure

    International Nuclear Information System (INIS)

    Djeffal, S.

    1984-07-01

    In the first part of this work a brief description of solid state nuclear track detectors, the principles of track registration and the different reading techniques are given. In the experimental part of the present work we systematically analysed different etching procedures and set a new electrochemical etching method, which enables us to develop a new fast neutron dosimeter. This fast neutron dosimeter makes possible the measurement of low neutron doses in the energy range from 10 Kev to 20 Mev with a reasonably flat energy response. These new developments are very attractive in personnel neutron dosimetry where nuclear emulsions are still used despite their insensitivity to neutron energies down to 500 Kev (i.e. the energy range one often encounters around nuclear facilities)

  6. Study of Indoor Radon /Thoron And Its Hazard Inside Kindergartens In Iraqi Kurdistan Using CR39 Nuclear Track Detectors

    International Nuclear Information System (INIS)

    Ismail, A.H.

    2007-01-01

    Indoor radon /thoron levels with potential alpha energy concentration PAEC), effective dose (H E ) and equilibrium factor (F) were measured using closed and open-can technique, containing CR-39 nuclear track detector. Measurements were carried during summer season inside different Kindergartens in three main regions (Erbil, Duhok and Sullimaniye) in Iraqi Kurdistan. We found that the radon and thoron densities range from (11 to 33 track.cm -2 .d -1 ) for radon and (8 to 29 track.cm -2 .d -1 ) for thoron, with the average radon concentration (96.81 26.939Bq/m 3 ) While an average (PAEC) and (H E ) was (7.68±2.298 mWL) , (2.306± 0.689 mSv/Y) respectively. On the other hands the average equilibrium factor was (0.291±0.01). Consequently, we believe that our results were done when we comparing them with the action levels were recommended by (lCRP 66). The results obtained indicate that various locations have different values of radon/thoron concentration. The differences can be ascribed to variations in grades of uranium at different locations and to some environmental factors such as ventilation, particle concentration, and the deposition of the progeny on surfaces or on the atmospheric aerosol

  7. A study of the effect of gamma and laser irradiation on the thermal, optical and structural properties of CR-39 nuclear track detector

    Science.gov (United States)

    Nouh, S. A.; Atta, M. R.; El-Melleegy, W. M.

    2004-08-01

    A comparative study of the effect of gamma and laser irradiation on the thermal, optical and structural properties of the CR-39 diglycol carbonate solid state nuclear track detector has been carried out. Samples from CR-39 polymer were classified into two main groups: the first group was irradiated by gamma rays with doses at levels between 20 and 300 kGy, whereas the second group was exposed to infrared laser radiation with energy fluences at levels between 0.71 and 8.53 J/cm(2). Non-isothermal studies were carried out using thermogravimetry, differential thermogravimetry and differential thermal analysis to obtain activation energy of decomposition and transition temperatures for the non-irradiated and all irradiated CR-39 samples. In addition, optical and structural property studies were performed on non-irradiated and irradiated CR-39 samples using refractive index and X-ray diffraction measurements. Variation in the onset temperature of decomposition T-o, activation energy of decomposition E-a, melting temperature T-m, refractive index n and the mass fraction of the amorphous phase after gamma and laser irradiation were studied. It was found that many changes in the thermal, optical and structural properties of the CR-39 polymer could be produced by gamma irradiation via degradation and cross-linking mechanisms. Also, the gamma dose has an advantage of increasing the correlation between thermal stability of the CR-39 polymer and bond formation created by the ionizing effect of gamma radiation. On the other hand, higher laser-energy fluences in the range 4.27-8.53 J/cm(2) decrease the melting temperature of the CR-39 polymer and this is most suitable for applications requiring molding of the polymer at lower temperatures.

  8. Measurement of concentrations of radon and its daughters in indoor atmosphere using CR-39 nuclear track detector

    International Nuclear Information System (INIS)

    Farid, S.M.

    1993-01-01

    This paper presents the results of the measurements of indoor 222 Rn and daughter levels in houses of different types located in different parts of Bangladesh. The passive time-integrated method of using a solid state nuclear track detector (CR-39) was employed for measuring both the 222 Rn gas concentration as well as the potential alpha energy exposure (PAEE) level from the short lived daughters of 222 Rn. The 222 Rn concentration from cup exposure and the PAEE from the bare exposure were obtained directly from the track density using calibration curves. A total of 275 exposures were made in the bare mode in 15 locations and 71 exposures in the cup mode in 6 locations. The geometric mean PAEE level obtained is 9.5 mWL with a geometric standard deviation of 1.9. The corresponding value for 222 Rn concentration are 61.3 Bq.M -3 and 2.4. The total data was collected over a period of one and a half year. The monthly variation of the geometric mean of PAEE is also shown. The annual effective dose equivalent has been estimated for each location by using the conversion factor of 9 mWv per WLM as obtained from ICRP-50. The average PAEE level obtained from the total data is below the intervention level as suggested by US EPA. However, the individual averages for each location show that in 8 out of 15 locations intervention may be considered and in others not intervention is called for. The 222 Rn concentrations at the seven locations are equal or less than the equilibrium equivalent 222 Rn concentration value as suggested by EPA. Attempts have also been made to see the variation in the PAEE levels according to different type of construction material used for the houses. (Author)

  9. Calibration factor determination for solid nuclear track detectors CR-39 type exposed to Rn-222; Determinacao do fator de calibracao para detectores solidos de tracos nucleares tipo CR-39 expostos a Rn-222

    Energy Technology Data Exchange (ETDEWEB)

    Cazula, Camila Dias; Campos, Marcia Pires de; Mazzilli, Barbara Paci, E-mail: cdcazula@ipen.br, E-mail: mpcampos@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    In the detection method with solid nuclear track detector, when a heavy particle rests on the detector surface, causes a breakdown in their molecular structure forming a trace. One of the typical applications of these detectors is the measurement of the concentration of Rn -222 in air, a noble radioactive gas, part of the U-238 series, emitting alpha particles and important in epidemiological studies to protect individuals from natural radiation. To determine the concentration of Rn -222 in the air in a room is necessary to know the density of lines (traces / cm{sup 2}) on the detector surface, the exposure time and the calibration factor. The determination of the calibration factor for CR-39 detectors was taken from the exposure of these to a known concentration of Rn-222. Therefore, the detectors were placed inside a cell of Lucas adapted and subsequently exposed to a concentration of Rn-222 15 kBq / m{sup 3}, by means of the apparatus RN-150 Pylon Electronics Incorporation, which has a source of Ra-226 and releases known concentrations of Rn-222. Six calibration factor determinations were performed, the average value obtained was 0.0534 ±0.0021 (traces / cm{sup 2} per Bq / m{sup 3} day). The results are consistent with literature values for the same type of detector and showed good reproducibility.

  10. Is CR39 worth the effort?

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1987-01-01

    CR39 proton sensitive track detectors were greeted by the radiation protection community at the end of the last decade as a major breakthrough for personnel neutron dosimetry. A number of laboratories eagerly began research on application of CR39 to their dosimetry needs. However, in the last two or three years the enthusiasm has subsided, and many health physicists have stopped working with the material. The number of participants using CR39 in the Oak Ridge National Laboratory Personnel Intercomparison Studies dropped from six in 1985 to three in 1986. On a national level, the Federal Republic of Germany with researchers active in CR39 research recently adopted an albedo system as their national standard. In contrast, the United States Department of Energy (DOE) is supporting development of a CR39 based combination dosimeter to meet Department wide dosimetry needs. The English National Radiological Protection Board (NRPB) now features the use of CR39 in the NRPB PADC(CR39). There has obviously been a range of experiences with CR39 in the dosimetry community. Why has this been the case, and what is the proper role for CR39 in personnel neutron dosimetry. 12 refs., 2 figs., 1 tab

  11. Response of CR-39 based personnel neutron dosemeter in terms of directional dose equivalent, in free air and on phantom

    International Nuclear Information System (INIS)

    Pal, Rupali R.; Sathian, Deepa; Jayalakshmi, V.; Chougaonkar, M.P.

    2011-01-01

    CR-39 is the most sensitive of nuclear track detectors for protons and is recommended as an effective neutron dosimeter because of it's low threshold energy of 100 keV neutrons. The fraction of protons that gives detectable tracks in CR-39 depends on the energy of the proton angle of incidence and etching conditions. As a consequence the registration efficiency of neutrons in the CR-39 plastics used for neutron personnel monitoring is strongly influenced by the direction of radiation incidence. This paper presents the relative response of CR-39 at varying neutron incident angles, for 241 Am-Be neutron source spectra in free air and on ISO phantom, in terms of operational quantities. It is observed that the angular dependence of CR-39 for irradiations in air and on phantom is essentially the same indicating that the phantom does not affect the directional response of CR-39. (author)

  12. Study of gamma irradiation effects on the etching and optical properties of CR-39 solid state nuclear track detector and its application to uranium assay in soil samples

    International Nuclear Information System (INIS)

    Amol Mhatre; Kalsi, P.C.

    2011-01-01

    The gamma irradiation effects in the dose range of 2.5-43.0 Mrad on the etching and optical characteristics of CR-39 solid state nuclear track detector (SSNTD) have been studied by using etching and UV-Visible spectroscopic techniques. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined. It is seen that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps of the unirradiated and the gamma -irradiated detectors determined from the UV-Visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. The present studies can be used for the estimation of gamma dose in the range of 2.5-43.0 Mrad and can also be used for estimating track registration efficiency in the presence of gamma dose. The CR-39 detector has also been applied for the assay of uranium in some soil samples of Jammu city. (author)

  13. Study of anomalous nuclear projectile fragments in reactions of 1.85A GeV 40Ar in CR-39 etched track detector

    International Nuclear Information System (INIS)

    Tincknell, M.L.; Price, P.B.

    1983-01-01

    Anomalous nuclear projectile fragments, or ''anomalons,'' were first observed in cosmic rays by nuclear emulsion as a rapid series of nuclear interactions in a short distance. They were later seen as a statistical anomaly in secondary mean-free-paths (mfp's) in cosmic rays, and most recently and convincingly observed in high-statistics experiments using Bevalac beams which showed short mfp's for secondary fragments measured within the first few centimeters after the primary interactions. Because of the controversial and provocative nature of these reports, an alternative technique with different systematic errors and methodology is essential to confirm and illuminate the anomalon phenomenon. CR-39 etched track detector provides this alternative. It allows sampling of the electric charge with high resolution at approximately 600 μm intervals along a nuclear track, and thus successive nuclear charge-changing interactions in short distances can be observed. We report here the observation of depressed secondary mfp's in the first centimeter or so beyond the primary interactions in CR-39, in agreement with the previous emulsion work

  14. The LLNL CR-39 personnel neutron dosimeter

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.; Westermark, J.

    1987-01-01

    We developed a personnel neutron dosimetry system based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This CR-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. 3 refs., 4 figs

  15. A new method for studying the transport of radon and thoron in various building materials using CR-39 and LR-115 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Ktata, A.; Bakhchi, A.

    2000-01-01

    Radon ( 222 Rn) and thoron ( 220 Rn) α-activities per unit volume were measured inside and outside different building materials by using two types of solid state nuclear track detectors (SSNTD) (CR-39 and LR-115 type II). In addition, the radon and thoron emanation coefficients of the studied materials were evaluated. Based on these data, the transport of radon and thoron across parallelepipedic blocks of the building materials could be investigated and radon and thoron global α-activities per unit volume outside different building material blocks were determined. Moreover, the diffusion length and the effective diffusion coefficient of radon in the building materials were evaluated and the total alpha activity due to radon in the atmospheres of different rooms consisting of different building materials was studied

  16. LET spectrum measurements in Cr-39 PNTD with AFM

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Carl Edward [Los Alamos National Laboratory; De Witt, Joel M [OSU, PHYSICS; Benton, Eric R [OSU, PHYSICS; Yasuda, Nakahiro [NIRS, HIMAC; Benton, Eugene V [UNIV OF SAN FRANCISCO

    2010-01-01

    Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}< 10 {mu}m) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching ({approx}< 1 {mu}m) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/{mu}m. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

  17. Radon emanation in a limestone cave using CR-39 and LR-115 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Oufni, L.; Misdaq, M.A.

    2001-01-01

    Radon alpha-activities were evaluated in different places of a quaternary cave, by using solid state nuclear track detectors (SSNTD). The maximum activity was detected in the place more moved back of the studied cave. The ventilation phenomenon has been investigated. The radon alpha activity and uranium content according to the growth of stalagmite and stalactite samples from the cave were evaluated. A positive correlation has been shown between the uranium distribution (radon) and the stratigraphic order of the stalagmite (and stalactite) samples. (author)

  18. Effect of Gamma Rays on Fast Neutron Registration in CR-39

    CERN Document Server

    Kobzev, A P; El-Halem, A A; Abdul-Ghaphar, U S; Salama, T A

    2002-01-01

    A set of CR-39 plastic detectors with front PE radiator was exposed to Am-Be neutron source, which has an emission rate of 0.86\\cdot 10^{7} sec^{-1}, and the neutron dose equivalent rate 1 m apart from the source is equal to 11 mrem/hr. Another set of samples was irradiated by a neutron dose of 4 rem, then exposed to different gamma-ray doses using ^{60}Co source. It was found that the track density grows with the increase of neutron dose and etching time. It was also found that the bulk etching rate V_{B}, the track diameter and the sensitivity of the CR-39 plastic detector with respect to the neutron irradiation increased with increasing gamma-ray dose in the range 1?10 Mrad. These results show that CR-39 can be considered as a promising fast neutron dosimeter and gamma-ray dosimeter.

  19. The Effect of Radiator on CR-39 Registration of Fast Neutrons

    International Nuclear Information System (INIS)

    El-Badrya, B.A.; Hegazya, T.M.; Morsya, A.A.; Zaki, M.F.

    2008-01-01

    Three different configurations of a personal neutron dosimeter using CR-39 plastic detector were placed in Plastiplast pouch composed from inside to outside of Aluminum ( 27 Al, 40 Ξ m), polyethylene (PE, 20 Ξ m), Cellulose Nitrate (CN, 40 Ξ m). One dosimeter was composed of a CR-39 detector and a PE radiator (1 mm thick), another of two CR-39 detectors with one serving as radiator, and the other of CR-39 alone (without radiator). These dosimeters have been irradiated with fast neutrons of average energy 4.5 MeV with neutron fluence ranging from 5.5 x 10 6 to 0.5 x 10 8 cm - 2 emitted from 241 Am-Be neutron source. The polymeric materials have been chosen on the basis of their hydrogen contents, which are as followed: CR-39, 48%, Polyethylene, 66.7% and CN, 32% by atomic ratio to produce protons via (n, p) elastic scattering with hydrogen and increasing the detection efficiency of CR-39. After irradiation, the dose equivalent response of the detectors has been studied by using conventional etching for two periods, 6h and 8h for these configurations. The thicknesses and compositions of the radiators are chosen so as to suppress the CR-39 response below 4 MeV by preventing the recoils of hydrogen nuclei, out of the hydrogen-rich radiators (PE, CR-39), from reaching the post-etch surface of the detector. Track counting was performed using an automated system. It was found that the dosemeter responses were linear as a function of a neutron equivalent dose and that the CR-39 detector has the same response with radiator or without radiator and thus appears as a promising fast neutron dosimeter. The results are discussed and compared with the literature

  20. Calibration of the Politrack® system based on CR39 solid-state nuclear track detectors for passive indoor radon concentration measurements.

    Science.gov (United States)

    Kropat, G; Baechler, S; Bailat, C; Barazza, F; Bochud, F; Damet, J; Meyer, N; Palacios Gruson, M; Butterweck, G

    2015-11-01

    Swiss national requirements for measuring radon gas exposures demand a lower detection limit of 50 kBq h m(-3), representing the Swiss concentration average of 70 Bq m(-3) over a 1-month period. A solid-state nuclear track detector (SSNTD) system (Politrack, Mi.am s.r.l., Italy) has been acquired to fulfil these requirements. This work was aimed at the calibration of the Politrack system with traceability to international standards and the development of a procedure to check the stability of the system. A total of 275 SSNTDs was exposed to 11 different radon exposures in the radon chamber of the Secondary Calibration Laboratory at the Paul Scherrer Institute, Switzerland. The exposures ranged from 50 to 15000 kBq h m(-3). For each exposure of 20 detectors, 5 SSNTDs were used to monitor possible background exposures during transport and storage. The response curve and the calibration factor of the whole system were determined using a Monte Carlo fitting procedure. A device to produce CR39 samples with a reference number of tracks using a (241)Am source was developed for checking the long-term stability of the Politrack system. The characteristic limits for the detection of a possible system drift were determined following ISO Standard 11929. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. High resolution alpha-autoradiography for measurement of 10B distribution in subcellular scale using CR-39 and AFM

    International Nuclear Information System (INIS)

    Amemiya, K.; Takahashi, H.; Yasuda, N.

    2000-01-01

    In order to measure 10 B distribution in tumor tissues for BNCT at subcellular scale, we have developed a new method for high resolution alpha-autoradiography using contact X-ray microscopy technique with CR-39 plastic track detectors. Sliced sections of boron-injected brain tumors in rats were mounted on CR-39 and irradiated with thermal neutrons at KUR. Then the samples were exposed to soft X-rays from a laser plasma source. After etching the CR-39 in NaOH solution for a short time (1-5 min.), transmission X-ray image of tumor cells appeared as relief on CR-39 surface, and could be observed with the atomic force microscopy (AFM). Very small etch pits of about 100 nm in diameter corresponding to particle tracks from 10 B(n, α) 7 Li reactions were also observed in the image simultaneously. This method provides an accurate distribution of 10 B inside the cell. (author)

  2. Use of CR-39 foils for personnel neutron dosimetry: improved electrochemical etching chambers and procedures

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.G.; Westermark, J.

    1986-01-01

    The electrochemical etching procedures for the new dosimetry system that uses foils of CR-39 plastic has been improved. During 1985, the etching chambers were modified to correct several problems and the changes to the etching procedures were studied, which gave a more uniform track density and size. The currently recommended etch parameters are given. A new generation of CR-39 material from the manufacturer proved to have a considerably lower background track density and a higher sensitivity; the new foils are also more uniform in thickness, which eliminates the need to numerically compensate for thickness variations. The energy dependence of the CR-39 using monoenergetic neutrons from accelerators at Battelle Northwest Laboratories and at Los Alamos National Laboratory was determined. Some variation was found in the energy dependence, but it is believed this was caused by changes in the etching procedures and by uncertainties in the fluences of the neutrons from the accelerators. A means by which the counting of CR-39 tracks may be automated is suggested; this would be very useful in adapting the CR-39 dosimetry system to large-scale use

  3. Estimation of track registration efficiency in solution medium and study of gamma irradiation effects on the bulk-etch rate and the activation energy for bulk etching of CR-39 (DOP) Solid State Nuclear Track Detector

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2010-01-01

    The fission track registration efficiency of diethylene glycol bis allyl carbonate (dioctyl phthalate doped) (CR-39 (DOP)) solid state nuclear track detector (SSNTD) in solution medium (K wet ) has been experimentally determined and is found to be (9.7 ± 0.5).10 -4 cm. This is in good agreement with the values of other SSNTDs. The gamma irradiation effects in the dose range of 50.0-220.0 kGy on the bulk etch rate, V b and the activation energy for bulk etching, E of this solid state nuclear track detector (SSNTD) have also been studied. It is observed that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation

  4. LET Spectrum Measurements In CR-39 PNTD With AFM

    Science.gov (United States)

    Johnson, C. E.; DeWitt, J. M.; Benton, E. R.; Yasuda, N.; Benton, E. V.

    2011-06-01

    Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range (˜recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching (˜<1 μm) following by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features inherently present in the post-etch detector surface. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/μm. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to 1 GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

  5. Investigations of CR39 dosimeters for neutron routine dosimetry

    International Nuclear Information System (INIS)

    Weinstein, M.; Abraham, A.; Tshuva, A.; German, U.

    2004-01-01

    CR-39 is a polymeric nuclear track detector which is widely used for neutron dosimetry. CR-39 detector development was conducted at a number of laboratories throughout the world(1,2) , and was accepted also for routine dosimetry. However, there are shortcomings which must be taken into consideration the lack of a dosimetry grade material which causes batch variations, significant angular dependence and a moderate sensitivity. CR-39 also under-responds for certain classes of neutron spectra (lower energy neutrons from reactors or high energy accelerator-produced neutrons).In order to introduce CR-39 as a routine dosimeter at NRCN, a series of checks were performed. The present work describes the results of some of our checks, to characterize the main properties of CR-39 dosimeters

  6. Study of the weekly irrigation cycle of a cultivated field in a semi-arid area (Marrakech region, Morocco) by using CR-39 and LR-115 II track detectors and radon as a natural tracer

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Essaouif, Z.

    2007-01-01

    Uranium ( 238 U) and thorium ( 232 Th) concentrations were measured in the soil of a cultivated field situated in a semi-arid area (Marrakech, Morocco) by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). The same track detectors were used for measuring alpha- and beta-activities due to radon and thoron gases emanating from the soil of the studied irrigated agricultural field. The influence of the humidity (soil water content), soil depth and climate conditions on the weekly irrigation cycle of the studied cultivated field was investigated by exploiting radon measurements

  7. Dose-rate effects on the bulk etch-rate of CR-39 track detector exposed to low-LET radiations

    CERN Document Server

    Yamauchi, T; Oda, K; Ikeda, T; Honda, Y; Tagawa, S

    1999-01-01

    The effect of gamma-rays and pulsed electrons has been investigated on the bulk etch rate of CR-39 detector at doses up to 100 kGy under various dose-rate between 0.0044 and 35.0 Gy/s. The bulk etch rate increased exponentially with the dose at every examined dose-rates. It was reveled to be strongly depend on the dose-rate: the bulk etch rate was decreased with increasing dose-rate at the same total dose. A primitive model was proposed to explain the dose-rate effect in which oxygen dissolved was assumed to dominate the damage formation process.

  8. Alkaline erosion of CR 39 polymer surfaces

    International Nuclear Information System (INIS)

    Faiman, Laurence

    2009-01-01

    We have investigated the mechanism of erosion of CR 39 polymer in alkaline environments. We observed the kinetics of absorption of water and methanol into both unirradiated and γ-irradiated samples. We use a capillary model to interpret our results. We etched our samples in both KOH solutions, and KOH solutions doped with methanol. Etch rate was desensitizing to γ-irradiation when KOH concentration approached saturation, but KOH solutions doped with methanol were not desensitizing, unlike with nuclear tracks. We account for this difference

  9. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

    Science.gov (United States)

    Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

    2015-08-01

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

  10. Optimization of CR-39 for fast neutron dosimetry applications

    CERN Document Server

    Vilela, E; Giacomelli, G; Giorgini, M; Morelli, B; Patrizii, L; Serra, P; Togo, V

    1999-01-01

    We present the results of an experimental work aimed at improving the performances of the CR-39[reg] (Registered Trademark of PPG Industries Inc.) nuclear track detector for neutron dosimetry applications. The work was done in collaboration with the Intercast Europe S.p.A., producer of CR-39 for commercial and scientific applications. We compare the CR-39 made with different additives concentrations and different polymerization processes. We evaluate the response of the CR-39 to fast neutrons from three sources: sup 2 sup 4 sup 1 Am-Be, sup 2 sup 5 sup 2 Cf and sup 2 sup 3 sup 8 Pu-Li. Particular attention was paid to background fluctuations that limit the lower detectable dose.

  11. Neutron detection using CR-39 and Atomic Force Microscopy (AFM)

    International Nuclear Information System (INIS)

    Vazquez L, C.; Fragoso, R.; Felix, R.; Golzarri, J.I.; Espinosa, G.; Castillo, F.

    2007-01-01

    AFM has been applied in many CR-39 track formation analyses. In this paper, the use of AFM in the neutron detection and analysis of the track formation is reported. The irradiation was made with an 1.5 GBq (0.5 Ci) 241 Am-Be neutron source, with and without a polyethylene radiator. The surface analysis was made to the CR-39 fresh material without irradiation, after the irradiation, and after a very short etching time. The results show important differences between the irradiation, with and without polyethylene radiator, and the latent tracks of the neutron in the CR-39 polycarbonate. The development of track formation after very short etching time and pits characterization were measured too using the AFM facilities. (Author)

  12. A fast method for the determination of the efficiency coefficient of bare CR-39 detector

    International Nuclear Information System (INIS)

    Dwaikat, Nidal; El-hasan, Mousa; Sueyasu, Masto; Kada, Wataru; Sato, Fuminobu; Kato, Yushi; Saffarini, G.; Iida, Toshiyuki

    2010-01-01

    A fast and simple method for the determination of the efficiency coefficient (η) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of η of bare CR-39 is found to be 0.20 ± 0.01 tracks cm -2 day -1 per Bq m -3 .

  13. A fast method for the determination of the efficiency coefficient of bare CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, Nidal, E-mail: nidaldwaiakt@yahoo.co [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan); Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); El-hasan, Mousa [Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Sueyasu, Masto; Kada, Wataru; Sato, Fuminobu; Kato, Yushi [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan); Saffarini, G. [Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Iida, Toshiyuki [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan)

    2010-10-15

    A fast and simple method for the determination of the efficiency coefficient ({eta}) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of {eta} of bare CR-39 is found to be 0.20 {+-} 0.01 tracks cm{sup -2} day{sup -1} per Bq m{sup -3}.

  14. The experimental and simulated LET spectrum and charge spectrum from CR-39 detectors exposed to irons near CRaTER at BNL

    International Nuclear Information System (INIS)

    Zhou, D.; Semones, E.; Guetersloh, S.; Zapp, N.; Weyland, M.; Benton, E.R.

    2010-01-01

    Human will be sooner or later return to the moon and will eventually travel to the planets near Earth. Space radiation hazards are an important concern for human space flight in deep space where galactic cosmic rays (GCR) and solar energetic particles are dominated and radiation is much stronger than that in LEO (Low Earth Orbit) because in deep space there is no magnetosphere to screen charged particle and no big planet nearby to shadow the spacecraft. Research indicates that the impact of particle radiation on humans depends strongly on the particles' linear energy transfer (LET) and the radiation risk is dominated by high LET radiation. Therefore, radiation research on high LET should be emphasized and conducted systematically so as to make radiation risk as low as reasonably achievable (ALARA) for astronauts. Radiation around the moon can be measured with silicon detectors and/or CR-39 plastic nuclear track detectors (PNTDs). At present stage the silicon detectors are one of the preferred active dosimeters which are sensitive to all LET and CR-39 detectors are the preferred passive dosimeters which are sensitive to high LET (≥5 keV/μm water). CR-39 PNTDs can be used as personal dosimeters for astronauts. Both the LET spectrum and the charge spectrum for charged particles in space can be measured with silicon detectors and CR-39 detectors. Calibrations for a detector system combined with the silicon detectors CRaTER (Cosmic Rays Telescope for the Effects of Radiation) from Boston University and Massachusetts Institute of Technology, and the CR-39 PNTDs from JSC (Johnson Space Center) - SRAG (Space Radiation Analysis Group) were conducted by exposing the detector system to the accelerator generated protons and heavy ions. US space mission for the radiation measurement around the moon using CRaTER was carried out in 2009. Results obtained from the calibration exposures indicate an excellent agreement between LET spectrum and charge spectrum measured with CR-39

  15. Proton radiographic characteristics of thin CR-39 detector

    International Nuclear Information System (INIS)

    Waheed, A.; Manzoor, S.; Khan, H.A.; Urlep, I.; Ilic, R.

    1991-01-01

    Two parameters, track registration sensitivity and densitometric response, were measured in radiography with a low energy (∼4.5 MeV) proton beam and a stack of thin (100μm) CR-39 detector foils. The optimum image quality was obtained at a layer removal thickness of about 1 μm. The image obtained under these conditions is characterized by a high track registration sensitivity (∼60%), high image contrast (the maximum value of the net optical density is ∼0.7) and high spatial resolution (∼1 μm). The application of the technique in biomedicine is illustrated by proton radiographs of botanical samples. (author)

  16. A comparative study on experimental and simulation responses of CR-39 to neutron spectra from a 252Cf source

    Directory of Open Access Journals (Sweden)

    Ghergherehchi Mitra

    2013-01-01

    Full Text Available A simulation of the interaction of neutrons emitted from a 252Cf source with a CR-39 detector is presented in this paper. Elastic and inelastic neutron interactions occur with the constituent materials of the CR-39 detector. Inelastic scatterings only consider (n, a and (n, p reactions. Fast neutrons tracks are, mainly, produced by recoil particle tracks in the plastic nuclear track detector as a result of the elastic scattering reaction of neutrons with the constituent materials of the solid-state nuclear track detectors, especially hydrogen nuclei. The energy of the neutron, incident position, direction, and type of interaction were sampled by the Monte Carlo method. The energy threshold, critical angle and scattering angle to the detector surface normal were the most important factors considered in our calculations. The energy deposited per neutron mass unit was calculated. The angular response was determined by both Monte Carlo simulation and experimental results. The number of visible proton tracks and energy deposited per neutron per visible track were calculated and simulated. The threshold energy of the recoil proton as a function of the thickness and incident proton angles was measured by the etchable range of protons at scattering angles, along with the shape and diameter of the track. Experimental and simulations result were in good agreement.

  17. The Use Of Optical Properties Of Cr-39 In Alpha Particle Equivalent Dose Measurements

    International Nuclear Information System (INIS)

    Shnishin, K.A.

    2007-01-01

    In this work, optical properties of alpha irradiated Cr-39 were measured as a function of optical photon wavelength from 200-1100 nm. Optical energy gap and optical absorption at finite wavelength was also calculated and correlated to alpha fluence and dose equivalent. Alpha doses were calculated from the corresponding irradiation fluence and specific energy loss using TRIM computer program. It was found that, the optical absorption of unattached Cr-39 was varied with alpha fluence and corresponding equivalent doses. Also the optical energy gab was varied with fluence and dose equivalent of alpha particles. This work introduces a reasonably simple method for the Rn dose equivalent calculation by Cr-39 track

  18. Calculating CR-39 Response to Radon in Water Using Monte Carlo Simulation

    International Nuclear Information System (INIS)

    Razaie Rayeni Nejad, M. R.

    2012-01-01

    CR-39 detectors are widely used for Radon and progeny measurement in the air. In this paper, using the Monte Carlo simulation, the possibility of using the CR-39 for direct measurement of Radon and progeny in water is investigated. Assuming the random position and angle of alpha particle emitted by Radon and progeny, alpha energy and angular spectrum that arrive at CR-39, the calibration factor, and the suitable depth of chemical etching of CR-39 in air and water was calculated. In this simulation, a range of data were obtained from SRIM2008 software. Calibration factor of CR-39 in water is calculated as 6.6 (kBq.d/m 3 )/(track/cm 2 ) that is corresponding with EPA standard level of Radon concentration in water (10-11 kBq/m 3 ). With replacing the skin instead of CR-39, the volume affected by Radon and progeny was determined to be 2.51 mm 3 for one m 2 of skin area. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/(Bq.h/m 3 ). Using the CR-39 for Radon measurement in water can be beneficial. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/ (Bq.h/m 3 ).

  19. Proton beam micromachining on PMMA, Foturan and CR-39 materials

    CERN Document Server

    Rajta, I; Kiss, A Z; Gomez-Morilla, I; Abraham, M H

    2003-01-01

    Proton Beam Micromachining was demonstrated at the Institute of Nuclear Research of the Hungarian Academy of Sciences using three different types of resists: PMMA, Foturan and CR-39 type Solid State Nuclear Track Detector material. Irradiations have been performed on the nuclear microprobe facility at ATOMKI. The beam scanning was done using a National Instruments (NI) card (model 6711), and the new C++ version of the program IonScan, developed specifically for PBM applications called IonScan 2.0. (R.P.)

  20. Study on response of CR-39 detector to light ions

    CERN Document Server

    Yamauchi, T; Oda, K

    1999-01-01

    The response of CR-39 detector has been obtained precisely for protons, deuterons, tritons, alpha-particles and lithiumions with energies of a few MeV/nucleon. The track etch rates were determined from the growth curves of pit radius and summarized as the response functions. The accuracy of this method is high enough to discriminate among hydrogen isotopes under a certain condition. The correlation between the response and LET with various cut-off energies has also been examined. It was found that LET is not an unique parameter describing the response function adequately for different ions by the same expression.

  1. Low energy alpha particle spectroscopy using CR-39 detector

    CERN Document Server

    Izerrouken, M; Ilic, R

    1999-01-01

    The possibility of using CR-39 to measure the depth profile of sup 1 sup 0 B in Si is analysed. The measuring technique exploits the sup 1 sup 0 B(n, alpha) sup 7 Li nuclear reaction. For this reason the track parameters (size, optical properties) of low energy alpha-particles (<1.47 MeV) were studied. The results showed that an energy resolution of about 100 keV could be obtained by an appropriate selection of etching conditions. The profile of sup 1 sup 0 B in Si at a depth as small as 1 mu m can be measured.

  2. gamma-induced modification on optical band gap of CR-39 SSNTD

    International Nuclear Information System (INIS)

    Zaki, M.F.

    2010-01-01

    effect of gamma irradiation on optical absorption of nuclear track detectors like CR-39 was studied at different absorbed doses using ultraviolet-visible (UV-VIS)spectroscopy. the existence of the peaks, their shifting and broadening as a result of gamma irradiation has been discussed. the width of the tail of localized states in the band gap (E u )was evaluated using the Urbach edge method. finally the indirect and direct band gap in pristine and gamma irradiated CR-39 have been determined. the values of indirect band gap have been found to be lower than the corresponding values of direct band gap. a decrease in the optical energy gap with increasing the gamma absorbed dose can be discussed on the basis of gamma-irradiation-induced defects in the CR-39. the correlation between optical band gap and the number of carbon atoms in a cluster with modified Tauc's equation has been discussed in case of CR-39.

  3. Personal Dosemeter of Thermal Neutron Using A Cr-39 Detector with Filter Natural LiF

    International Nuclear Information System (INIS)

    Sofyan, Hasnel; Thamrin, M.Thoyib

    1996-01-01

    The research of personal dosemeter for thermal neutron using Cr-39 detector with different thicknesses of natural LiF filter was carried out. The irradiation of Cr-39 detector with neutron source from reactor research TRIGA mark II of Rikkyo University Tokyo, Japan. Nuclear track was counted by automatic method with ASPECT ver.4.22 Series A4T124 software and manual method for correction. The result of research, the maximum of nuclear tracks was obtained at 8 mm of LiF filter was 10 mm with 11,630x10E-5 track/neutron for air radiation. And on phantom radiation, the thickness of filter was 10 mm with 11,630x10E-5 track/neutron. Its values were 3.6 and 7.5 bigger than the response of Cr-39 non filter in air and on phantom radiation, respectively

  4. Incident-angle dependency found in track formation sensitivity of a plastic nuclear track detector (TD-1)

    International Nuclear Information System (INIS)

    Yasuda, Hiroshi

    1999-01-01

    The present study was done since data are hardly available on the incident-angle dependency of track formation sensitivity (S) of the plastic nuclear track detector. Chips of a TD-1 plate, an antioxidant-doped CR-39 (diethyleglycol-bis-allylcarbonate, HARZLAS, Fukuvi Chem. Ind.), were used as a high-LET radiation detector and were exposed to heavy ion beams of C, Ne, and Si under different incident angles in Heavy Ion Medical Accelerator in Chiba of National Institute of Radiological Sciences. After exposed and etched, the chips were observed with an optical microscope and a program for image analysis to calculate S. The S values calculated were found smaller for the beams having lower incident angles. Thus the estimated LET values from the S-LET relationship for vertical incident beams showed large reduction for low-angle particles. Those potential errors should be quantified and corrected in determination of LET spectra in space. (K.H.)

  5. Efficient alpha particle detection by CR-39 applying 50 Hz-HV electrochemical etching method

    International Nuclear Information System (INIS)

    Sohrabi, M.; Soltani, Z.

    2016-01-01

    Alpha particles can be detected by CR-39 by applying either chemical etching (CE), electrochemical etching (ECE), or combined pre-etching and ECE usually through a multi-step HF-HV ECE process at temperatures much higher than room temperature. By applying pre-etching, characteristics responses of fast-neutron-induced recoil tracks in CR-39 by HF-HV ECE versus KOH normality (N) have shown two high-sensitivity peaks around 5–6 and 15–16 N and a large-diameter peak with a minimum sensitivity around 10–11 N at 25°C. On the other hand, 50 Hz-HV ECE method recently advanced in our laboratory detects alpha particles with high efficiency and broad registration energy range with small ECE tracks in polycarbonate (PC) detectors. By taking advantage of the CR-39 sensitivity to alpha particles, efficacy of 50 Hz-HV ECE method and CR-39 exotic responses under different KOH normalities, detection characteristics of 0.8 MeV alpha particle tracks were studied in 500 μm CR-39 for different fluences, ECE duration and KOH normality. Alpha registration efficiency increased as ECE duration increased to 90 ± 2% after 6–8 h beyond which plateaus are reached. Alpha track density versus fluence is linear up to 10 6  tracks cm −2 . The efficiency and mean track diameter versus alpha fluence up to 10 6  alphas cm −2 decrease as the fluence increases. Background track density and minimum detection limit are linear functions of ECE duration and increase as normality increases. The CR-39 processed for the first time in this study by 50 Hz-HV ECE method proved to provide a simple, efficient and practical alpha detection method at room temperature. - Highlights: • Alpha particles of 0.8 MeV were detected in CR-39 by 50 Hz-HV ECE method. • Efficiency/track diameter was studied vs fluence and time for 3 KOH normality. • Background track density and minimum detection limit vs duration were studied. • A new simple, efficient and low-cost alpha detection method

  6. Investigation of Nuclear Fragmentation in Relativistic Heavy Ion Collisions Using Plastic - Nuclear - Track Detectors

    CERN Multimedia

    2002-01-01

    In this experiment CR39 plastic nuclear track detectors will be used which are sensitive to detect relativistic nuclear fragments with charges Z@$>$5. They will be analyzed using an automatic track measuring system which was developed at the University of Siegen.\\\\ \\\\ This allows to measure large quantities of tracks in these passive detectors and to perform high statistics experiments. We intend to measure cross sections for the production of nuclear fragments from heavy ion beams at the SPS. \\\\ \\\\ The energy independence of the cross sections predicted by the idea of limiting fragmentation will be tested at high energies. In exposures with different targets we plan to analyze the factorization of the fragmentation cross sections into a target depending factor and a factor depending on the beam particle and the fragment. The cross sections for one proton remov Coulomb dissociation. \\\\ \\\\ We plan to investigate Coulomb dissociation for different targets and different energies. Fragment and projectile charges ...

  7. Nuclear Fragmentation Induced by Relativistic Projectiles Studied in the 4$\\pi$ Configuration of Plastic Track Detectors

    CERN Multimedia

    2002-01-01

    % EMU19 \\\\ \\\\ The collisions of heavy ions at relativistic energies have been studied to explore a number of questions related with hot and dense nuclear matter in order to extend our knowledge of nuclear equation-of-state. There are other aspects of these interactions which are studied to expound the process of projectile and/or target disintegrations. The disintegrations in question could be simply binary fissions or more complex processes leading to spallation or complete fragmentation. These important aspects of nuclear reactions are prone to investigations with nuclear track detectors. \\\\ \\\\One of the comparatively new track detector materials, CR-39, is sensitive enough to record particles of Z~$\\geq$~6 with almost 100\\% efficiency up to highly relativistic energies. The wide angle acceptance and exclusive measurements possible with plastic track detectors offer an opportunity to use them in a variety of situations in which high energy charged fragments are produced. The off-line nature of measuring tra...

  8. Range to cone length relations for light ions in CR-39

    International Nuclear Information System (INIS)

    Gil, L.R.; Marques, A.

    1988-01-01

    Curves ''range x cone lenght'' and ''diameter x cone lenght'' are calculated for tracks left by low energy light ions in CR-39. The calculations cover ions from helium to iron and are performed for 6.25 N NaOH at 70 0 C and a standard etching time but can be easily extended to other etching conditions. (author) [pt

  9. A comparison of the neutron response of CR-39 made by different manufacturers

    International Nuclear Information System (INIS)

    Ipe, N.E.; Liu, J.C.; Buddemeier, B.R.; Miles, C.J.; Yoder, R.C.

    1991-09-01

    CR-39 was obtained from American Acrylics and Plastics, Inc. (A.A), N. E. Technology, Ltd. (N.E), and Tech/Ops Landauer, Inc. (LT). The dosemeters were exposed to radioisotopic neutron sources at SLAC, and moderated 252 Cf at ORNL. The A.A. and N.E. dosemeters were electrochemically etched (pre-etch in 6.5 N KOH at 60 degrees C for 1 hour and 45 minutes, a 5 hour etch at 3000 V and 60 Hz, a 23 minute blow-up step at 2 kHz and a post-etch for 15 minutes). Track densities were determined with the Homann Track Size Image Analyzer. The LT dosemeters were chemically etched in 5.5 N NaOH at 70 degrees C for 15.5 hours. Some A.A., N.E., and LT dosemeters were etched in 6.25 N NaOH at 70 degrees C for 6 hours. A pre-etch step in 60% methanol and 40% NaOH at 70 degrees C for 1 hour was added for some N.E. dosemeters. The results of these studies are reported in this paper. 3 refs., 2 figs., 2 tabs

  10. Response of CR-39 SSNTD to high energy neutrons using zirconium convertors - a Monte Carlo and experimental study

    International Nuclear Information System (INIS)

    Pal, Rupali; Sapra, B.K.; Bakshi, A.K.; Datta, D.; Biju, K.; Suryanarayana, S.V.; Nayak, B.K.

    2016-01-01

    Neutron dosimetry in ion accelerators is a challenging field as the neutron spectrum varies from thermal, to fast and high-energy neutrons usually extending beyond 20 MeV. Solid-state Nuclear Track Detectors (SSNTDs) have been increasingly used in numerous fields related to nuclear physics. Extensive work has also been carried out on determining the response characteristics of such detectors as nuclear spectrometers. In nuclear reaction studies, identification of reaction products according to their type and energy is frequently required. For normally incident particles, energy-dispersive track-diameter methods have become useful scientific tools using CR-39 SSNTD. CR-39 along with 1 mm polyethylene convertor can cover a neutron energy range from 100 keV to 10 MeV. The neutron interacts with the hydrogen in CR-39 producing recoil protons from elastic collisions. This detectable neutron energy range can be increased by modification in the radiator/convertor used along with CR-39. CR39 detectors placed in conjunction with judiciously chosen thicknesses of a polyethylene radiator and a lead absorber (or degrader) are used to increase energy range upto 19 MeV. A portable neutron counter has been proposed for high-energy neutron measurement with 1 cm thick Zirconium (Zr) as the converter outside a spherical HDPE shell of 7 inch diameter. Zr metal has been found to show (n,2n) cross section for energies above 10 MeV starting from 0.01 barns for 8 MeV upto 1 barns for 22 MeV. Above these energies, the experimental data is scarce. In this paper, Zr was used in conjunction with CR-39 which showed an enhancement of track density on the CR-39. This paper demonstrates the enhancement of neutron response using Zr on CR-39 with both theoretical and experimental studies

  11. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    Energy Technology Data Exchange (ETDEWEB)

    Benton, E.R. [Eril Research, Inc., Stillwater, Oklahoma (United States); Deme, S.; Apathy, I. [KFKI Atomic Energy Research Institute, Budapest (Hungary)

    2006-07-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca{sub 2}SO{sub 4}:Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET{sub {infinity}}H{sub 2}O {>=} 10 keV/{mu}m, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component {>=} 10 keV/{mu}m measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/{mu}m measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 {mu}Gy/day and dose equivalent rates ranging from 340 to 450 {mu}Sv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  12. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    International Nuclear Information System (INIS)

    Benton, E.R.; Deme, S.; Apathy, I.

    2006-01-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca 2 SO 4 :Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET ∞ H 2 O ≥ 10 keV/μm, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component ≥ 10 keV/μm measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/μm measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 μGy/day and dose equivalent rates ranging from 340 to 450 μSv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  13. Proton Radiography with CR-39 by Using the Protons from High Power Femto-second Laser System

    International Nuclear Information System (INIS)

    Choi, Chang Il; Lee, Dong Hoon; Kang, Byoung Hwi; Kim, Yong Kyun; Choi, Il Woo; Ko, Do Kyeong; Lee, Jong Min

    2008-01-01

    Proton radiography techniques are useful to obtain a high quality image of a thin object, because protons travel straight in matter. Generation of the high energy proton using conventional accelerator costs high and requires large accelerating facility. But proton radiography using high power femto-second(10-15 second) laser has been interested, because it can generate high energy protons at lower price than the conventional accelerator like a cyclotron. For this study, we used the CR-39 SSNTD (Solid State Nuclear Track Detector) as the proton radiography screen. Commonly, CR-39 is used to detect the tracks of energetic charged particles. Incident energetic charged particles left latent tracks in the CR-39, in the form of broken molecular chains and free radicals. These latent tracks show high chemical reactivity. After chemical etching with the caustic alkali solution such as NaOH or KOH, tracks are appeared to forms of hole. If protons with various energies enter the two targets with another thickness, number of protons passed through the target per unit area is different each other. Using this feature of protons, we can a proton radiographic image with CR-39. We studied proton radiography with CR-39 by using energetic protons from high power femto-second laser and evaluated potentiality of femto-second laser as new energetic proton generator for radiography

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  15. Effects of additives and impurities on the properties of CR-39 neutron dosimeters

    International Nuclear Information System (INIS)

    Tarle, G.

    1982-01-01

    Several problems have plagued users of commercial CR-39 for neutron dosimetry work. Large variations in sensitivity have been observed in samples received from different manufacturers, from different batches from the same manufacturer and even within a given sheet. The latter variations have taken several forms. Clear etching regions of lower sensitivity near the gasket and sometimes extending well away from the gasket in drip-like patterns have been observed. Large demarcated patches of differing sensitivity and sensitivity variations with depth have been found in many commercial samples of CR-39. In addition, we have observed a general roughening of the post-etch surface and a patchiness of bulk etching associated with contact patterns of adjacent sheets, which have been stored for extended (greater than or equal to 6 mos) periods of time. All of these problems combine to make commercially available CR-39 unreliable as a neutron dosimeter. In an attempt to identify and correct the causes of these problems, a systematic study of the effects of additives, impurities and manufacturing conditions on the uniformity of CR-39 track detectors has been undertaken, and is reported in this paper

  16. Detection of fission fragments and alpha particles using the solid trace detector CR-39

    International Nuclear Information System (INIS)

    Santos, R.C.

    1988-01-01

    The technique of detecting charged particles using the solid track detector CR-39 is employed to establish some characteristics of fission fragments and alpha particles emitted from a Cf-252 source. Results are presented and discussed on the following aspects i) distribution of the track diameters; ii) variations on the track diameters to the chemical attack; iii) variations of the chemical attack velocity with respect to concentration and temperature. iv) activation energy of the developping process; v) induction time; vi) critical angle and efficiency on track developping. (A.C.A.S.) [pt

  17. Experimental test for interpreting the increase in sensibility of doped CR-39

    Science.gov (United States)

    Laville, A.; Perez-Peraza, J.; Alvarez, M.; Estrada, M. R.

    1985-01-01

    In recent years the sensibility of CR-39 to nuclear tracks has been increased by doping the corresponding monomer with dioctyl phtalate. At this regard, two theoretical approaches are current managed to explain this phenomenon: either the doping react with the active radicals in the chain blocking them, stopping crosslinking between chains, or alternatively that the doping gets between them giving wider space between the crosslinkined chains.

  18. Impact of x-ray dose on the response of CR-39 to 1-5.5 MeV alphas

    International Nuclear Information System (INIS)

    Rojas-Herrera, J.; Rinderknecht, H. G.; Zylstra, A. B.; Gatu Johnson, M.; Orozco, D.; Rosenberg, M. J.; Sio, H.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2015-01-01

    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray uences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-K α and K β x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula

  19. Characterization of saturation of CR-39 detector at high alpha-particle fluence

    Directory of Open Access Journals (Sweden)

    M. El Ghazaly

    2018-04-01

    Full Text Available The occurrence of saturation in the CR-39 detector reduces and limits its detection dynamic range; nevertheless, this range could be extended using spectroscopic techniques and by measuring the net bulk rate of the saturated CR-39 detector surface. CR-39 detectors were irradiated by 1.5 MeV high alpha-particle fluence varying from 0.06 × 108 to 7.36 × 108 alphas/cm2 from Am-241 source; thereafter, they were etched in a 6.25N NaOH solution at a temperature of 70°C for different durations. Net bulk etch rate measurement of the 1.5 MeV alpha-irradiated CR-39 detector surface revealed that rate increases with increasing etching time and reaches its maximum value at the end of the alpha-particle range. It is also correlated with the alpha-particle fluence. The measurements of UV–Visible (UV–Vis absorbance at 500 and 600 nm reveal that the absorbance is linearly correlated with the fluence of alpha particles at the etching times of 2 and 4 hour. For extended etching times of 6, 10, and 14.5 hour, the absorbance is saturated for fluence values of 4.05 × 108, 5.30 × 108, and 7.36 × 108 alphas/cm2. These new methods pave the way to extend the dynamic range of polymer-based solid state nuclear track detectors (SSNTDs in measurement of high fluence of heavy ions as well as in radiation dosimetry. Keywords: Alpha Particle, Bulk Etch Rate, CR-39 Detector, Saturated Regime, UV–Vis Spectroscopy

  20. [Neutron Dosimetry System Using CR-39 for High-energy X-ray Radiation Therapy].

    Science.gov (United States)

    Yabuta, Kazutoshi; Monzen, Hajime; Tamura, Masaya; Tsuruta, Takao; Itou, Tetsuo; Nohtomi, Akihiro; Nishimura, Yasumasa

    2014-01-01

    Neutrons are produced during radiation treatment by megavolt X-ray energies. However, it is difficult to measure neutron dose especially just during the irradiation. Therefore, we have developed a system for measuring neutrons with the solid state track detector CR-39, which is free from the influence of the X-ray beams. The energy spectrum of the neutrons was estimated by a Monte Carlo simulation method, and the estimated neutron dose was corrected by the contribution ratio of each energy. Pit formation rates of CR-39 ranged from 2.3 x 10(-3) to 8.2 x 10(-3) for each detector studied. According to the estimated neutron energy spectrum, the energy values for calibration were 144 keV and 515keV, and the contribution ratios were approximately 40:60 for 10 MV photons and 20:70 for photons over 15 MV. Neutron doses measured in the center of a high-energy X-ray field were 0.045 mSv/Gy for a 10 MV linear accelerator and 0.85 mSv/Gy for a 20 MV linear accelerator. We successfully developed the new neutron dose measurement system using the solid track detector, CR-39. This on-time neutron measurement system allows users to measure neutron doses produced in the radiation treatment room more easily.

  1. Exposure of CR39 Stacks to Oxygen and Sulphur Beams at the CERN-SPS

    CERN Multimedia

    2002-01-01

    We plan to expose 8 stacks of CR39 sheets to oxygen and sulphur ions of 60 and 200~GeV at the CERN-SPS.\\\\ \\\\ The main purpose of the exposures is the calibration of the CR39 sheets used for a large area experimental search for magnetic monopoles at the Gran Sasso Laboratory (experiment MACRO). \\\\ \\\\ The stacks have 20~layers of CR39, each layer 13~cm~x~7~cm and 1.4~mm thick. A copper absorber is located after the first 6 layers. \\\\ \\\\ We require exposures of about 2000 tracks per cm$^2$ over the entire area of the stack with a uniform illumination. The standard beam used for the emulsion experiments is normally adequate for this purpose.\\\\ \\\\ We have performed one exposure to sulphur ions. The etched tracks have been measured automatically with the Elbeck image analyser system. We measured the incoming sulphur ions as well as the nuclear fragments produced in the copper absorber. Clean separation among the peaks due to the various fragments is obtained (there is no indication of nuclei with fractional electri...

  2. Development of optical monitor of alpha radiations based on CR-39.

    Science.gov (United States)

    Joshirao, Pranav M; Shin, Jae Won; Vyas, Chirag K; Kulkarni, Atul D; Kim, Hojoong; Kim, Taesung; Hong, Seung-Woo; Manchanda, Vijay K

    2013-11-01

    Fukushima accident has highlighted the need to intensify efforts to develop sensitive detectors to monitor the release of alpha emitting radionuclides in the environment caused by the meltdown of the discharged spent fuel. Conventionally, proportional counting, scintillation counting and alpha spectrometry are employed to assay the alpha emitting radionuclides but these techniques are difficult to be configured for online operations. Solid State Nuclear Track Detectors (SSNTDs) offer an alternative off line sensitive technique to measure alpha emitters as well as fissile radionuclides at ultra-trace level in the environment. Recently, our group has reported the first ever attempt to use reflectance based fiber optic sensor (FOS) to quantify the alpha radiations emitted from (232)Th. In the present work, an effort has been made to develop an online FOS to monitor alpha radiations emitted from (241)Am source employing CR-39 as detector. Here, we report the optical response of CR-39 (on exposure to alpha radiations) employing techniques such as Atomic Force Microscopy (AFM) and Reflectance Spectroscopy. In the present work GEANT4 simulation of transport of alpha particles in the detector has also been carried out. Simulation includes validation test wherein the projected ranges of alpha particles in the air, polystyrene and CR-39 were calculated and were found to agree with the literature values. An attempt has been further made to compute the fluence as a function of the incidence angle and incidence energy of alphas. There was an excellent correlation in experimentally observed track density with the simulated fluence. The present work offers a novel approach to design an online CR-39 based fiber optic sensor (CRFOS) to measure the release of nanogram quantity of (241)Am in the environment. © 2013 Elsevier Ltd. All rights reserved.

  3. Neutron measurement in 12,13C+ 27Al system using CR-39 detectors and neutron rem meter

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Tripathy, S.P.; Shanbhag, A.A.; Sunil, C.; Joshi, D.S.; Sarkar, P.K.

    2011-01-01

    In this work, neutron measurements carried out for the interaction of 60 and 67.5 MeV 12 C, 57.3 and 65 MeV 13 C ions with thick aluminium target by using CR-39 detectors and neutron rem meter is reported. Both the detector systems were irradiated at different angles viz. 0 deg, 30 deg, 60 deg, 90 deg with respect to the beam direction. The normalized track density measurements (tracks/cm 2 /projectile at 1m) in CR-39 detectors were correlated with the normalized dose equivalent values (μSv/projectile at 1m) obtained using the neutron rem meter. The track density was found to be more in case of 13 C than 12 C. However in all the cases, the track density per incident projectile was found to decrease as the angle with respect to beam direction increases, indicating non-isotropic nature of neutron emission. The ratio between measured dose equivalent in rem meter to the measured track densities in CR-39 detectors was found to be 2.8±0.2, which remains constant irrespective of the change in angle from beam direction as well as neutron spectrum, indicating a flat dose response of CR-39 detectors. (author)

  4. The influence of chemical etching time on efficiency of radon detection using CR-39

    International Nuclear Information System (INIS)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C.; Del Claro, Flavia; Paschuk, Sergei A.; Correa, Janine N.

    2015-01-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of 222 Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of 222 Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  5. Employment of the polycarbonates Makrofol-DE and CR-39 for neutron radiography

    International Nuclear Information System (INIS)

    Pereira, Marco Antonio Stanojev

    2000-01-01

    The track-etch method was employed for Neutron Radiography purposes. The solid state nuclear track detectors Makrofol-DE and CR-39 together with a natural boron converter screen have been used as imaging systems. In order to determine their radiographic characteristics, the imaging systems were irradiated up to neutron exposures around 6x10 10 /cm 2 in a radiography facility installed at the IEA-R1 Nuclear Research Reactor and the detectors developed between 2 and 65 minutes. The main goal of this work was determine the radiography conditions for which the best contrast and resolution are obtained at the image. These conditions are: - Makrofol-DE: neutron exposure between 2x10 9 n/cm 2 and 2x10 10 n/cm 2 and developing time 6 minutes; CR-39: neutron exposure between 3x10 9 n/cm 2 and 2x10 10 n/cm 2 and developing time 25 minutes. The present results were compared with those ones determined to other track detectors, and discussed according to the theory of the image formation in solid state nuclear track detectors based on the optical properties of a single track. (author)

  6. Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Paul, S.; Tripathy, S.P.; Sharma, S.C.; Jena, S.; Rout, S.; Joshi, D.S.; Bandyopadhyay, T.

    2014-01-01

    Effects of high-dose neutron irradiation on chemical and optical properties of CR-39 were studied using FTIR (Fourier Transform Infrared) and UV–vis (Ultraviolet–Visible) spectroscopy. The primary goal was to find a correlation between the neutron dose and the corresponding changes in the optical and chemical properties of CR-39 resulted from the neutron irradiation. The neutrons were produced by bombarding a thick Be target with 22-MeV protons. In the FTIR spectra, prominent absorbance peaks were observed at 1735 cm −1 (C=O stretching), 1230 cm −1 (C–O–C stretching), and 783 cm −1 (=C–H bending), the intensities of which decreased with increasing neutron dose. The optical absorbance in the visible range increased linearly with the neutron dose. Empirical relations were established to estimate neutron doses from these optical properties. This technique is particularly useful in measuring high doses, where track analysis with an optical microscope is difficult because of track overlapping. - Highlights: • CR-39 optical absorbance measurements can be used for neutron dosimetry instead of track counting. • The technique is particularly useful for measuring high doses. • Effects of neutron irradiations on various properties of CR-39 have been characterized

  7. The development of an automatic scanning method for CR-39 neutron dosimeter

    International Nuclear Information System (INIS)

    Tawara, Hiroko; Miyajima, Mitsuhiro; Sasaki, Shin-ichi; Hozumi, Ken-ichi

    1989-01-01

    A method of measuring low level neutron dose has been developed with CR-39 track detectors using an automatic scanning system. It is composed of the optical microscope with a video camera, an image processor and a personal computer. The focus point of the microscope and the X-Y stage are controlled from the computer. The minimum detectable neutron dose is estimated at 4.6 mrem in the uniform field of neutron with equivalent energy spectrum to Am-Be source from the results of automatic measurements. (author)

  8. STUDYING THE STRUCTURAL, OPTICAL, CHEMICAL AND ELECTROCHEMICAL ETCHING CHANGES OF CR-39 FOR DOSEMETRIC APPLICATIONS.

    Science.gov (United States)

    Zaki, M F; Elshaer, Y H; Taha, Doaa H

    2017-12-01

    The present work shows the induced modification of the structural, optical, chemical etching and electrochemical etching parameters of CR-39 irradiated with alpha-particles. CR-39 polymer track detectors were irradiated with different fluences (1.62 × 106, 2.72 × 106, 3.82 × 106 and 5.21 × 106 particles/cm2) of alpha-particles using 241Am source. The structural and optical properties were measured by FT-IR spectroscopy, X-ray diffraction and UV/Vis spectroscopy, respectively. The FT-IR spectra reveal that no major changes in the typical functional groups of irradiated polymer detectors. The X-ray diffraction patterns show that a broad band in the region of 12° 27°, which refers to the presence of the combination of amorphous and crystalline phases. UV/Vis responses of irradiated polymer track detectors exhibit a single absorption band in the range of 254-352 nm that is correlated to the occurrence of electronic transition. Also, the changes in the chemical and electrochemical parameters due to alpha-irradiation are examined and thoroughly discussed. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. The influence of chemical etching time on efficiency of radon detection using CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C., E-mail: adrireway@hotmail.com, E-mail: jaquelinekappke@gmail.com, E-mail: daninarloch@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Fisica; Del Claro, Flavia; Paschuk, Sergei A., E-mail: flaviadelclaro@gmail.com, E-mail: spaschuk@gmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Programa de Pos-Graduaca em Engenharia Eletrica e Informatica Industrial; Correa, Janine N., E-mail: janine_nicolosi@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Construcao Civil

    2015-07-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of {sup 222}Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of {sup 222}Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  10. Method of plastic track detector electrochemical etching

    International Nuclear Information System (INIS)

    D'yakov, A.A.

    1984-01-01

    The review of studies dealing with the development of the method for the electro-chemical etching (ECE) of the plastic track detectors on the base of polyethy-leneterephthalate (PET) and polycarbonate (PC) is given. Physical essence of the method, basic parameters of the processes, applied equipment and methods of measurement automation are considered. The advantages of the method over the traditional chemical etching are pointed out. Recommendations on the detector operation modes when detecting fission fragments, α-particles and fast neutrons are given. The ECE method is based on the condition that during chemical etching the high-voltage sound frequency alternating electric field is applied to the detector. In this case the detector serves as an isolating layer betWeen two vessels with etching solution in which high-voltage electrode are submerged. At a fixed electric field potential higher (over than the threshold value) at the end of the etching track cone atree-like discharge spot arises. It is shown that when PET is used for fast neutron detection it is advisable to apply for ECE the PEW solution (15g KOH+40 g C 2 H 2 OH + 45g H 2 O) the field potential should constitute 30 kVxcm -1 at the freqUency of 9 kHz. In the case of fission fragment detection Using ECE and PC the following ECE conditions are recommended: 30% KOH etcher, field potential of 10 kVxcm -1 , 2-4 kHz frequency. It is concluded that the ECE method permits considerably eXtend the sphere of plastic track detector application for detecting ionizing particles,

  11. Suitability of CR-39 dosimeters for personal dosimetry around CANDU reactors

    International Nuclear Information System (INIS)

    Cross, W.G.

    1992-08-01

    The capabilities and limitations of CR-39 damage track detectors have been evaluated for their use as personal neutron dosimeters around CANDU reactors. Since the energy response is a critical characteristic, the neutron energy spectra expected within CANDU containments were studied. In the boiler rooms, around the moderator cooling systems, and in most of the fueling machine vaults, the spectra vary considerably, but the majority of the dose is expected to be delivered by neutrons above 80 keV, the approximate threshold for electrochemically-etched CR-39 detectors. In the Pickering A fueling machine vault, and in areas in other stations to which neutrons from reactors have been multiply scattered, lower energy neutrons may be important. In nearly all areas where people work, it appears that working times will be limited by gamma rays rather than by neutrons. The characteristics of other neutron dosimeters - bubble and superheated drop detectors, albedo detectors, and Si real-time detectors - were also reviewed. For workers who typically receive neutron doses that are small compared with regulatory limits, CR-39 is the most suitable available dosimeter for demonstrating compliance. All single dosimeters have poor angular response over the range 0 to 180 degrees because of the shielding of the body. Albedo and Si detectors have particularly poor energy responses over the energy range of importance. Bubble and superheated drop detectors have the advantages of immediate readout and high sensitivity, but the disadvantages of inability to integrate doses over a long period, temperature dependence, very limited range and higher cost. (Author) (110 refs., 45 figs.)

  12. Effects of high gamma doses on the bulk etch rate of two grade CR-39 materials

    International Nuclear Information System (INIS)

    Brahimi, S.; Lounis-Mokrani, Z.; Imatoukene, D.; Badreddine, A.; Abdelaziz, F.Z.; Allab, M.

    2008-01-01

    In this study, the effect of gamma pre-treatment on etching rates has been investigated on CR-39 detectors manufactured by Pershore Mouldings (PM) as standard grade and (PM355) as dosimetry grade. The detectors have been exposed to 60 Co gamma rays at absorbed dose ranging from 0 to 10 5 Gy. The chemical etching was carried out in four PEW solutions (potassium ethanol in water) with various concentrations (KOH 6.25 N with 0%, 20%, 40% and 60% of ethanol). The results show that the effect of gamma rays on CR-39 etching characteristics is more pronounced when the ethanol concentration increases in the etching solution especially in the region ranging from 10 3 to 10 4 Gy. In this range, V B etching rate decreases till values less than those observed for virgin material. The structural alterations (cross linking or main chain scissions) produced by gamma rays in this plastic detector have been determined using UV-visible and FTIR spectroscopy and compared to those induced by proton irradiation

  13. Operational trials of single- and multi-element CR-39 dosemeters for the DIDO and PLUTO reactors at the Harwell Laboratory

    International Nuclear Information System (INIS)

    Gallacher, G.G.; Perks, C.A.

    1993-01-01

    Single- and multi-element CR-39 dosemeters, developed at the Harwell Laboratory, and a commercially available multi-element CR-39 dosemeter (obtained from Track Analysis Systems Ltd), were evaluated for their potential as neutron dosemeters for personnel working at Harwell Laboratory's research reactors. Owing to the angular dependence of the CR-39 (processed using electrochemical etching), the single-element dosemeter was found to be impractical. Consequently, a multi-element dosemeter was developed, which consisted of a cube of side 36 mm with CR-39 elements (also processed using electrochemical etching) attached to each of the sides. Although this dosemeter was technically suitable for this type of dosimetry, it was considered to be unacceptably bulky in personnel trials. The commercially available CR-39 dosemeter tested was much smaller (the CR-39 was only chemically etched) and this was considered to be acceptable as a personnel dosemeter. In addition, trials with personnel working at active handling glove boxes indicated that single-element dosemeters might be adequate, but further work would be needed to verify this. (author)

  14. Cr-39 fast neutron dosemeter based on A (n, α) converter

    International Nuclear Information System (INIS)

    Widayati, S.; Budiantari, T.

    1998-01-01

    The aim of this experiment is to obtained the response of Cr-39 as fast neutron dosemeter based on an (n, α) converter. Cr-39 was irradiated to AmBe fast neutron flux from 0.10 mSv to 2.5 mSv. Cr-39 processed by chemical etching with NaOH 20 % at temperature of 60 oC in six hours. The results of experiment showed that the response of Cr-39 based on an (n, α) converter is 6 times bigger than the response of Cr-39 without (n, α) converter. (author)

  15. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, G. D., E-mail: gdsut@mit.edu; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Zylstra, A. B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rosenberg, M. J.; Glebov, V. Yu. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States)

    2016-11-15

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  16. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Science.gov (United States)

    Sutcliffe, G. D.; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.; Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S.; Zylstra, A. B.; Rosenberg, M. J.; Glebov, V. Yu.

    2016-11-01

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  17. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    International Nuclear Information System (INIS)

    Sutcliffe, G. D.; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.; Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S.; Zylstra, A. B.; Rosenberg, M. J.; Glebov, V. Yu.

    2016-01-01

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  18. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, G. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Milanese, L. M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Orozco, D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Lahmann, B. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Gatu Johnson, M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Séguin, F. H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Sio, H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Frenje, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Li, C. K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Park, H. -S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Rygg, J. R. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Casey, D. T. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Bionta, R. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Turnbull, D. P. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Huntington, C. M. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Zylstra, A. B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA; Rosenberg, M. J. [Laboratory for Laser Energetics, Rochester, New York 14623, USA; Glebov, V. Yu. [Laboratory for Laser Energetics, Rochester, New York 14623, USA

    2016-08-05

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  19. Determination of the exhalation rate of radon and thoron from building materials by detectors Cr-39

    International Nuclear Information System (INIS)

    Vasidov, A.

    2005-01-01

    Full text: The building materials (BM) such as granite, bricks, sand, cement etc., contain uranium and thorium in various amounts. Therefore the knowledge of true value exhalation rate of Rn and Tn from BM represents scientific and practical interest in environmental radiation protection. In present work, we have used calibrated plastic cups with two detectors Cr-39. The detected surface of the cup is situated in perpendicular position surface BM and were exposed for 20-30 days. The first detector fixed the bottom on distance from surface of BM and records alpha particles from Rn-222 only. The second detector records alpha particles of the thoron and radon. After exposition, the detectors chemically etched and analyzed. The values of the exhalation rate per unit area of the granite, concrete, fired and unfired bricks, sand, cement, alabaster varied 0.091 - 0.1 Bq m -2 h -1 for the radon, 200 - 5800 Bq m -2 h - 1 for the thoron, accordingly

  20. Response of CR-39 Detector Against Fast Neutron Using D-Polyethylene and H-Polyethylene Radiator

    International Nuclear Information System (INIS)

    Sofyan, Hasnel

    1996-01-01

    The research on the response of detector CR-39 by using D-Polyethylene and H-Polyethylene radiator has been carried out. The optimum number of nuclear tracks was found with the use of 30 % NaOH at 80 + 0,5oC for 80 minutes of etching time. The comparison of CR-39 detector response caused by D-Polyethylene radiator against H-Polyethylene radiator of irradiation in air, were found to be 1.18 and 0.84 for 241Am-Be neutron source and neutron source from reactor respectively. For phantom irradiation, the results were found to be 1.75 for 241Am-Be neutron source, and 0.77 for neutron source from reactor

  1. The effect of infrared laser on the activation energy of CR-39 polymeric detector

    Energy Technology Data Exchange (ETDEWEB)

    Saffarini, G., E-mail: safarini@najah.edu [Radiation Physics Laboratory, Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Dwaikat, Nidal; El-Hasan, Mousa [Radiation Physics Laboratory, Department of Physics, An-Najah National University, Nablus, Palestine (Country Unknown); Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki [Department of Electronics, Information Systems and Energy Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka (Japan)

    2012-07-11

    The effect of infrared laser of wavelength ({lambda}=1064 nm), pulse energy of 40 mJ/pulse at a repetition rate of 10 Hz, on the activation energy of CR-39 polymer, solid state nuclear track detector, has been investigated. Fifteen detectors were divided into three sets of equal numbers. The first set (un-exposed to laser beam), used as a reference set, was irradiated in close contact with an alpha source ({sup 241}Am). The second set (post-exposed) was first exposed to alpha radiation in close contact to the same {sup 241}Am source and then treated in air with laser at energy intensity 8 J/cm{sup 2}. For the third set (pre-exposed), the process was reversed (laser+alpha) under the same conditions. The activation energies of bulk etch (E{sub B}) for unexposed, post-exposed and pre-exposed are found to be equal to 0.98, 0.91, and 1.0 eV, respectively. The respective activation energies of track etch (E{sub T}) for unexposed, post-exposed and pre-exposed are found to be equal to 0.71, 0.75, and 0.97 eV. These results show that E{sub B} for post-exposed and pre-exposed samples remain, to within the experimental uncertainty, comparable to that of un-exposed sample which indicates that laser irradiation has a small effect on E{sub B}. Also, the results of E{sub T} for post-exposed and un-exposed samples are in close proximity with a slight increase for the former. The increase in E{sub T} of pre-exposed CR-39 polymer due to IR exposure is discussed on the basis of cross linking processes occurring during the exposure. This increase in E{sub T} leads to the hardening of the detector material of the pre-exposed sample. The hardening of the detector material is crucial in applications of CR-39 polymer such as in cosmic ray and cold fusion research.

  2. Assessment of alpha radioactivity in lipstick, nailpolish, toothpaste and vermilion using CR-39 detector.

    Science.gov (United States)

    Ghosh, Dipak; Deb, Argha; Maiti, Sunil; Haldar, Subrata; Bera, Sukumar; Sengupta, Rosalima; Bhaitacharyya, Rini

    2010-04-01

    Human beings are always exposed to radiation from chemical cosmetics. In order to collect information regarding the radioactivity of chemical cosmetics used in our daily life, we studied the alpha radioactivity in different cosmetics samples, such as lipsticks, nail-polish, toothpaste and vermilion. The significant accumulation ofradionuclide in and on the tissues, directly or indirectly exposed due to the lipsticks, toothpaste, vermilion, may cause health hazards. Different samples of these cosmetic materials (Indian and foreign brands) were collected from the local markets of Kolkata, India. CR-39--a useful solid state nuclear track detector (SSNTD) was used to detect alpha radioactivity of these samples. Such exhaustive measurement of radioactivity in lipsticks, nail-polish, toothpaste and vermilion has not been reported so far.

  3. Environmental dosimetry of radon-222 and daughters: measurement of absolute calibration factors of CR-39 considering the plate-out effects and environmental factors

    International Nuclear Information System (INIS)

    Paulo, S.R. de.

    1991-08-01

    The subject of this work concerns with the measurement of absolute calibration factors for the use of CR-39 as an absolute detector in indoor and daughters monitoring. Up to now the usefulness of calibration factors was restricted to environmental conditions equal (or very close) to those worthing during their determinations. This fact is consequence of the difficulties related to the understanding of the plate-out properties of radon daughters activity in the air. The plate-out effects on radon daughters monitoring performed by SSNTDs are studied. Our experimental results are in agreement with those of other authors about the great sensitivity of CR-39 to the plate-out effects, fact that recommended its use in this work. Being succeeded in the employment of CR-39 as an alpha-spectrometer we concluded that some important information (like the radon daughters deposition rates on the walls of an environment) can be achieved. The knowledge about the behavior of plate-out made possible the determination of the ranges in zenithal angle and energy where CR-39 can detect alpha-particles with efficiency of 100%, at our conditions of track observation. In this way, we obtained calibration factors for CR-39 that are weakly dependent on environmental conditions. We think that these results can contribute to the improvement of RD (Radiation Detector) detection techniques. (author). 159 refs, 106 figs, 05 tabs

  4. The effect of ArF laser irradiation (193 nm) on the photodegradation and etching properties of alpha-irradiated CR-39 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Shakeri Jooybari, B. [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Nuclear Science and Technology Research Institute (NSRT), Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Ghergherehchi, M. [College of Information and Technology/ school of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Afarideh, H., E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Lamehi-Rachti, M. [Nuclear Science and Technology Research Institute (NSRT), Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2015-01-01

    The effects of ArF laser irradiation (λ=193nm) at various fluences (energy dose or energy density) on the etching properties of pre-exposed (laser + alpha) CR-39 detectors were studied. First, UV–Vis and Fourier transform infrared (FTIR) spectra were acquired for non-laser-irradiated and laser-irradiated samples to detect the influence of the ArF laser on the chemical modification of the CR-39. Changes observed in the spectra indicated that the predominant process that occurred upon ArF laser irradiation was a bond-scission process. Thereafter, the mean track and bulk etching parameters were experimentally measured in ArF-laser-irradiated CR-39 detectors exposed to an alpha source ({sup 241}Am, E = 5.49 MeV). Inhomogeneous regions in the laser-irradiated side of the CR-39 demonstrated a variable etching rate on only the front side of the CR-39 detector. New equations are also presented for the average bulk etching rate for these inhomogeneous regions (front side). The mean bulk and track etching rates and the mean track dimensions increased in a fluence range of 0–37.03 mJ/cm{sup 2} because of photodegradation and the scission of chemical bonds, which are the predominant processes in this range. When the fluence was increased from 37.03 to 123.45 mJ/cm{sup 2}, the bulk and track etching rates and the track dimensions slowly decreased because of the formation of cross-linked structures on the CR-39 surface. The behavior of the bulk and track etching rates and the track dimensions appears to be proportional to the dose absorbed on the detector surface. It was observed that as the etching time was increased, the bulk and track etching rates and the track dimensions of the laser-irradiated samples decreased because of the shallow penetration depth of the 193 nm laser and the reduction in the oxygen penetration depth.

  5. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  6. Development of neutron dosimeter using CR-39 for measurement of ambient dose equivalent

    International Nuclear Information System (INIS)

    Maki, Daisuke; Shinozaki, Wakako; Ohguchi, Hiroyuki; Yamamoto, Takayoshi; Nakamura, Takayoshi

    2010-01-01

    A CR-39 has good advantages such as cumulative type dosimeter, small fading effect and gamma-ray insensitive. Therefore, we developed the wide energy-range environmental neutron dosimeter using eight CR-39s for area monitoring in this study. This dosimeter is made of octagonal columnar polyethylene block which height is 60 mm and bottom side is 25 mm. The dosimeter contains two types of CR-39s for fast neutron detection and slow neutron detection. Four CR-39s for fast neutron detection are used for detection of recoil protons produced by H (n, p) reactions. Four CR-39s for slow neutron detection are used with boron nitride converter to detect alpha-rays produced by 10 B (n, α) 7 Li reactions. Ambient dose equivalent is obtained by adding the number of etch-pits observed in four CR-39s for fast neutron detection to the number of etch-pits observed in four CR-39s for slow neutron detection with appropriate constants respectively. Dosimeters were irradiated with some energetic neutrons and evaluated results of ambient dose equivalent were compared with results from neutron transport calculations. Energy response of dosimeter shows good agreement with neutron fluence to ambient dose equivalent conversion coefficients. Directional dependence of dosimeter is at the same level as the rem-counter. (author)

  7. Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry.

    Science.gov (United States)

    Sahoo, G S; Paul, S; Tripathy, S P; Sharma, S C; Jena, S; Rout, S; Joshi, D S; Bandyopadhyay, T

    2014-12-01

    Effects of high-dose neutron irradiation on chemical and optical properties of CR-39 were studied using FTIR (Fourier Transform Infrared) and UV-vis (Ultraviolet-Visible) spectroscopy. The primary goal was to find a correlation between the neutron dose and the corresponding changes in the optical and chemical properties of CR-39 resulted from the neutron irradiation. The neutrons were produced by bombarding a thick Be target with 22-MeV protons. In the FTIR spectra, prominent absorbance peaks were observed at 1735cm(-1) (C=O stretching), 1230cm(-1)(C-O-C stretching), and 783cm(-1)(=C-H bending), the intensities of which decreased with increasing neutron dose. The optical absorbance in the visible range increased linearly with the neutron dose. Empirical relations were established to estimate neutron doses from these optical properties. This technique is particularly useful in measuring high doses, where track analysis with an optical microscope is difficult because of track overlapping. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Ablation and cone formation mechanism on CR-39 by ArF laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shakeri Jooybari, B., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Nuclear Science and Technology Research Institute NSRT, Tehran (Iran, Islamic Republic of); Afarideh, H., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Lamehi-Rachti, M. [Nuclear Science and Technology Research Institute NSRT, Tehran (Iran, Islamic Republic of); Ghergherehchi, M. [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); College of Information and Communication Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-03-07

    In this work, chemical properties, surface modification, and micro structures formation on ablated polyallyl di-glycol carbonate (CR-39) polymer by ArF laser irradiation (λ = 193 nm) at various fluences and pulse number were investigated. CR-39 samples have been irradiated with an ArF laser (193 nm) at a repetition rate of 1 Hz. Threshold fluence of ablation and effective absorption coefficient of CR-39 were determined. Conical microstructures (Taylor cone) formed on laser-ablated CR-39 exhibit: smooth, Taylor cone shape walls and sharp tips together with interference and well defined fringe-structure with a period of 230 nm, around cone base. Mechanism of cone formation and cone evolution of CR-39 ablated surface were investigated by change of fluences (at a given pulse number) and pulse number (at a given fluence). Cone height, cone base, and region of interface were increased in micrometer steps by increasing the total fluence. Depression on the base of the cone and the circular fringe were simulated. FTIR spectra were measured and energy dispersive x-ray analysis of irradiated and un-irradiated samples was performed.

  9. HZE dosimetry in space using plastic track detectors

    CERN Document Server

    Kopp, J; Reitz, G; Enge, W

    1999-01-01

    Plastic nuclear track detectors were used to measure the contribution of High charge Z and energy E (HZE) particles to the radiation exposure of manned space missions. Results from numerous space missions in the orbit planned for the International Space Station are compared. The measurements cover the declining phase of the last solar cycle during the past 7 years and various shielding conditions inside the US Space Shuttle and the Russian MIR-station.

  10. 3-D imaging of particle tracks in solid state nuclear track detectors

    Directory of Open Access Journals (Sweden)

    D. Wertheim

    2010-05-01

    Full Text Available It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

  11. Low-level radon measurements by nuclear track detectors

    International Nuclear Information System (INIS)

    Koksal, E. M.; Goksel, S. A.; Alkan, H.

    1985-01-01

    In the work to be described here we have developed a passive nuclear track dosimeter to measure the integrated value of indoor radon (Rn-222) over a long period of time. Passive radon dosimeter which we have developed in our laboratories makes use of two small pieces of CR-39 plastic (Allyl diglycol carbonate) as detectors for registering tracks of alpha particles emitted by radon. These CR-39 plastic detectors are fixed on the inside bottom of a cup-shaped polystrene enclosure which is closed at the top by a tissue permeable for gases only. CR-39 detectors exposed to radon gas in the indoor air for a period of six months then are removed and chemically etched to make the alpha particle tracks visible under the microscope. The counts of tracks are evaluated to determine the radon concentration in the air in comparison with the number of tracks produced by a known concentration of radon gas. By using the passive dosimeters developed and the chemical etching procedure descriped here, measurements of indoor radon concentrations were carried out in 45 houses in different districts of the city of Istanbul. In this pilot experiment mean radon concentrations between 0.7 and 3.5 pCi/l have been found in these houses. In order to improve the counting of alpha tracks produced on the detectors a prototype electrochemical etching system in addition to chemical etching, is being developed. (author)

  12. The effects of pre-etching time on the characteristic responses of electrochemically etched CR-39 neutron dosimeters

    International Nuclear Information System (INIS)

    Sohrabi, M.; Khoshnoodi, M.

    1986-01-01

    The effects of pre-etching time (PET) or duration of etching of fast-neutron-induced-recoil tracks in CR-39 in 6N KOH at 60 0 C on electrochemical etching neutron characteristic responses; i.e. sensitivity and mean recoil track diameter (MRTD) versus KOH normality up to 18N are investigated in this paper. Six sets of responses for PETs of 0, 1, 2, 3, 4, and 5 hours were obtained by using our new multi-chamber ECE (MCECE) system which reduced total operation time to about 6% of the time usually required when single-chamber ECE systems are used. The sensitivity response for zero PET showed a broad plateau and a high sensitivity low-LET peak around 16N. By increasing PET, another peak was also developed around 5N leading to 'double-humped' responses with two maximums around 5N and 16N, and a minimum around 11N. On the other hand, the MRTD responses for all PETs studied showed the same general trend with maximums around 11N. In this paper, shape of tracks under different conditions are also investigated, new optimum conditions such as KOH concentrations of 5, 11, and 15N at 25 0 C, with or without pre-etching, are recommended for tracks of lower-LET recoils including possibly protons, and alpha particle tracks over a broad energy range, and the efficiency of the MCECE system is also demonstrated. (author)

  13. Relation between the size of fog droplets and their contact angles with CR39 surfaces

    International Nuclear Information System (INIS)

    Grosu, G; Andrzejewski, L; Veilleux, G; Ross, G G

    2004-01-01

    The formation of fog on CR39 surfaces has been studied. Water droplets form fog coalesce with time, especially during the first 20 s at the beginning of the formation of fog. Consequently, their mean diameter increases. Formation of fog being related to the wettability of the surfaces, the latter has been increased by the implantation of Ar ions into CR39 surfaces under an oxygen partial pressure. A very wetting CR39 surface with advancing (ACA) and receding (RCA) contact angles below 5 deg. has been obtained with an implantation dose of 1.28x10 17 Ar + cm -2 . In this condition, no formation of fog was observed. Characterization using x-ray photoelectron spectroscopy has shown that the molecular structure of CR39 is strongly modified by Ar + implantation, which would be responsible for the increase in wettability. Unfortunately, both ACA and RCA increase with time, which is called ageing, and the formation of fog is again observed. The diameter and concentration of water droplets forming fog have been plotted against the contact angle. These plots show that no formation of fog occurs for ACA 15 He + cm -2 and an energy of 2 keV, sufficient to push the ions deeper than the Ar depth profile, delays the ageing effect in such a way that ACA ≅ 40 deg. is reached after ∼2000 h and no formation of fog is observed during these first ∼2000 h

  14. Annealing effects on the charged particles registration characteristic of the CR-39 traces solid detector

    International Nuclear Information System (INIS)

    Correa, M.M.

    1989-10-01

    CR-39 trace solid detectors samples, previously exposed to alpha particles and fission fragments from a Cf-252 source, were submitted to a annealing treatment to study his effects on the characteristics of charged particle traces registration. (L.C.J.A.)

  15. Radon measurements technique in air using a track plastic detector

    International Nuclear Information System (INIS)

    Pereira, J.F.A.; Silva Estrada, J.J. da; Binns, D.A.C.; Urban, M.

    1983-01-01

    A difusion chamber is used to measure the radon concentration in air through alpha particles tracks in Makrofol E, 300μm thick. This system was developed by Karlsruhe Nuclear Research Centre, Germany, and is already used by the Occupational Radiological Protection Department of IRD/CNEN, for premilimar measurements in Pocos de Caldas and Rio de Janeiro. In the chamber, the plastic detector is set at the lower end and a filter is placed at the upper end. In this way, a known volume is defined in the detector system. To amplify the tracks produced by the alpha particles due to radon and short-lived dadon-daughter products, an electrochemical system is employed. Some theoretical questions about the treeing produced by the electrochemical etching, the detector characteristics, as well as the adapted statistics model are also discussed. (Author) [pt

  16. Interaction of low-intensity nuclear radiation dose with the human blood: Using the new technique of CR-39NTDs for an in vitro study

    International Nuclear Information System (INIS)

    Ismail, Asaad H.; Jaafar, Mohamad S.

    2011-01-01

    Complete blood counts were analyzed for 30 samples of human blood with radiation dose rate ranging between 10 and 41 μSv/h using a Radium-226 source with different time of exposure. A new technique involving a nuclear track detector type CR-39(CR-39 NTDs) was used to estimate the alpha particle density incident on the blood samples. The results show that the ranges of alpha particle in blood samples and on the surface of CR-39NTDs vary exponentially with energy of alpha particles. This depends on the restricted energy loss and target density. Changes in the blood components due to irradiation occurred for different durations of irradiation, and the duration of irradiation that influenced the blood samples in this study was 6 min. The change in red blood cell (RBC) was negligible, so it is less affected than other blood components. In addition, most changes in the blood contents began at a low radiation dose (10.38-13.41 μSv/h). For the doses 13.41-21.77 μSv/h, platelet (PLT) counts increased rapidly and adversely with the RBC and white blood cell (WBC) due to chromosomal aberration. Besides, rapid PLT count reduction rapidly at high dose (42.1 μSv h) causes thrombocytopenia; in contrast, WBC increased, which is an indication of cancer caused due to increase in alpha particle dose. Generally, our results are in agreement with the essentials of blood content and the principles of biological radiation interaction.

  17. The precise energy spectra measurement of laser-accelerated MeV/n-class high-Z ions and protons using CR-39 detectors

    Science.gov (United States)

    Kanasaki, M.; Jinno, S.; Sakaki, H.; Kondo, K.; Oda, K.; Yamauchi, T.; Fukuda, Y.

    2016-03-01

    The diagnosis method, using a combination of a permanent magnet and CR-39 track detectors, has been developed to separately measure the energy spectrum of the laser-accelerated MeV/n-class high-Z ions and that of MeV protons. The main role of magnet is separating between high-Z ions and protons, not for the usual energy spectrometer, while ion energy was precisely determined from careful analysis of the etch pit shapes and the etch pit growth behaviors in the CR-39. The method was applied to laser-driven ion acceleration experiments using CO2 clusters embedded in a background H2 gas. Ion energy spectra with uncertainty ΔE  =  0.1 MeV n-1 for protons and carbon/oxygen ions were simultaneously obtained separately. The maximum energies of carbon/oxygen ions and protons were determined as 1.1  ±  0.1 MeV and 1.6  ±  0.1 MeV n-1, respectively. The sharp decrease around 1 MeV n-1 observed in the energy spectrum of carbon/oxygen ions could be due to a trace of the ambipolar hydrodynamic expansion of CO2 clusters. Thanks to the combination of the magnet and the CR-39, the method is robust against electromagnetic pulse (EMP).

  18. Determination of exhalation rate of radon from walls and indoor radon by CR-39 detectors

    International Nuclear Information System (INIS)

    Vasidov, A.; Tillaev, T.S.

    2007-01-01

    Full text: The knowledge of true value exhalation rate of radon gas from building materials represents scientific and practical interest in environmental radiation protection. This point of view in the paper exhalation rate of radon gas from building materials and a surface of walls with different constructions were determined by detectors CR-39. The values of the exhalation rate of radon per unit area of the granite, concrete, fired and unfired bricks, sand, cement, alabaster varied 0.091 - 0.1 Bq·m -2 ·h -1 . The surface of walls of dwellings constructed from different building materials the exhalation rate of radon are within in limits of 0.083-1.12 Bq·m -2 ·h -1 . Were measurements with CR-39 detectors a level of radon within 50-520 Bq/m 3 in air of rooms constructed of the different building materials

  19. A passive rem counter based on CR39 SSNTD coupled with a boron converter

    CERN Document Server

    Agosteo, S; Ferrarini, c, M; Silari, M

    2009-01-01

    A passive neutron rem counter using a CR39 SSNTD coupled with a boron converter has been developed. The rem counter is a polythene sphere with cadmium and lead insets, designed to have a response function proportional to the fluence to ambient dose equivalent conversion coefficients, H*(10)/Φ, for energies ranging from thermal up to 1 GeV. At its centre is a thermal neutron detector made of a CR39 SSNTD coupled with an enriched boron neutron converter. The rem counter was first calibrated at CERN and at the Politecnico di Milano, and then tested in high-energy neutron fields at GSI, Darmstadt, Germany and at the CERF facility at CERN. Its most important features are a very high neutron sensitivity and conversely a complete insensitivity to gamma radiation.

  20. Regular self-microstructuring on CR39 using high UV laser dose

    International Nuclear Information System (INIS)

    Parvin, P.; Refahizadeh, M.; Mortazavi, S.Z.; Silakhori, K.; Mahdiloo, A.; Aghaii, P.

    2014-01-01

    The UV laser induced replicas in the form of self-lining microstructures are created by high dose (with high fluence) ArF laser irradiation on CR39. Microstructures as the self-induced contours, in the form of concentric circles, appear when the laser fluence is well above the ablation threshold. It leads to the regular periodic parallel lines, i.e. circles with large radii having spatial separation 100–200 nm and line width 300–600 nm, where the number of shots increases to achieve higher UV doses. The surface wettability is also investigated after laser texturing to exhibit that a notable hydrophilicity takes place at high doses.

  1. Testing Novel CR-39 Detector Deployment System For Identification of Subsurface Fractures, Soda Springs, ID

    Energy Technology Data Exchange (ETDEWEB)

    McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Carpenter, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brandon, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zavala, Bernie [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    The Environmental Protection Agency (EPA) has teamed with Battelle Energy Alliance, LLC (BEA) at Idaho National Laboratory (INL) to facilitate further testing of geologic-fracture-identification methodology at a field site near the Monsanto Superfund Site located in Soda Springs, Idaho. INL has the necessary testing and technological expertise to perform this work. Battelle Memorial Institute (BMI) has engaged INL to perform this work through a Work for Others (WFO) Agreement. This study continues a multi-year collaborative effort between INL and EPA to test the efficacy of using field deployed Cr-39 radon in soil portals. This research enables identification of active fractures capable of transporting contaminants at sites where fractures are suspected pathways into the subsurface. Current state of the art methods for mapping fracture networks are exceedingly expensive and notoriously inaccurate. The proposed WFO will evaluate the applicability of using cheap, readily available, passive radon detectors to identify conductive geologic structures (i.e. fractures, and fracture networks) in the subsurface that control the transport of contaminants at fracture-dominated sites. The proposed WFO utilizes proven off-the-shelf technology in the form of CR-39 radon detectors, which have been widely deployed to detect radon levels in homes and businesses. In an existing collaborative EPA/INL study outside of this workscope,. CR-39 detectors are being utilized to determine the location of active transport fractures in a fractured granitic upland adjacent to a landfill site at the Fort Devens, MA that EPA-designated as National Priorities List (NPL) site. The innovative concept of using an easily deployed port that allows the CR-39 to measure the Rn-222 in the soil or alluvium above the fractured rock, while restricting atmospheric Rn-222 and soil sourced Ra from contaminating the detector is unique to INL and EPA approach previously developed. By deploying a series of these

  2. Practical consequences for the use of a personal dosimeter for fast neutrons based on CR39 exposed up to one year

    International Nuclear Information System (INIS)

    Boschung, Markus; Fiechtner, Annette; Mayer, Sabine; Wernli, Christian

    2008-01-01

    Full text: At the Paul Scherrer Institut a personal neutron dosimetry system based on chemically etched CR-39 detectors and automatic track counting is in routine use since 1998. In its original design, the dosimeter is sensitive to thermal neutrons and to neutrons in the energy range from 200 keV up to several MeV. The standard exposition period is 3 months. Recently, a novel concept for individual monitoring was implemented at CERN. In this concept, each worker who possibly enters a radiation zone is equipped with a combined dosimeter for the measurement of personal photon and neutron doses. The dosimeter for photon dose measurement has an instant readout capability and dose measurements are done monthly. The dosimeter for neutron measurement is based on CR-39 detectors and is sensitive to fast neutrons only. The CR-39 detector is only evaluated and a neutron dose determined if the monthly personal photon dose exceeds 2 mSv or if the exposition period of the neutron dosimeter exceeds one year. This novel regime of use of the neutron dosimeter has had some important consequences for its practical implementation. A priori, the wearing period of a neutron dosimeter is not known and can range from 1 month up to 12 or even more months. A good knowledge of the long-term behaviour and characteristics of the detector material is needed. But also organisational and administrative issues have to be considered. The paper will outline the adopted procedure covering not only technical but also organisational aspects. The long-term behaviour of background track density and response to 241 Am-Be over one year are described as well as calibrations performed with 241 Am-Be and 252 Cf sources and in the High-Energy Reference Field Facility at CERN (CERF). The concept of individual monitoring at CERN could be transferred to other locations with high energy accelerators such as PSI and DESY. The experience gained with the neutron dosimeter based on CR-39 since introduction of the

  3. Intercomparatives study of the detection characteristics of the CR-39 SSNTD for light ions: Present status of the Besancon-Dresden approaches

    CERN Document Server

    Brun, C; Jouffroy, M; Meyer, P; Groetz, J E; Abel, F; Chambaudet, A; Dörschel, B; Hermsdorf, D; Bretschneider, R; Kadner, K; Kuehne, H

    1999-01-01

    For the last few years, the Besancon and Dresden teams have been working in a parallel way on light ion (protons and alphas) registration characteristics for the CR-39 SSNTD. Even if the two groups use different approaches, the main part of both investigations concerns the study of the track etch rate (V sub T) and the consequences of the obtained results, which have provided us with greater understanding of detection limits. After recalling the methods used to determine the V sub T from both teams, we will show how fundamental data related to the registration properties of the CR-39 detector can be extracted. Indeed, the knowledge of an analytical relation for the V sub T enables the relationship between this velocity and the primary deposited energy to be examined with respect to the same spatial variable (the instantaneous depth of penetration (x) of the incoming particle). According to experimental uncertainties, the Bragg peak of the primary ionization coincides within a very close range with the maximum...

  4. $\\bar{p}$-Induced Fission Studies with Plastic Track Detectors Using 4$\\pi$-Geometry

    CERN Multimedia

    2002-01-01

    % EMU20 \\\\ \\\\ The annihilation of a stopped antiproton on the surface of a target nucleus produces on the average five pions with a mean energy of 230~MeV. The high excitation of the nuclei with low angular momentum transfer can also be achieved by direct pion-nucleus interactions. The fission probabilities of highly excited nuclei can be explained on the basis of high energy limit of statistical theory. Previously the binary fission and higher multiplicity break-up of various nuclei caused by the absorption of pions has been studied by our group. The mechanism of nuclear excitation may still be the same when an antiproton annihilates in a nucleus and produces pions. It would be interesting to see whether the $\\bar{p}$ annihilation produces high enough excitation energies for nuclear phase-transition to take place. If so, then the fragmentation would overwhelm binary and ternary fission process. \\\\ \\\\The use of a highly sensitive plastic detector, CR-39, was made by our group in a number of studies involving ...

  5. Study of variations in structural, optical parameters and bulk etch rate of CR-39 polymer due to electron irradiation

    International Nuclear Information System (INIS)

    Sahoo, G. S.; Joshi, D. S.; Tripathy, S. P.; Bandyopadhyay, T.

    2016-01-01

    In this work, electron induced modifications on the bulk etch rate, structural and optical parameters of CR-39 polymer were studied using gravimetric, FTIR (Fourier Transform Infrared) and UV–vis (Ultraviolet–Visible) techniques, respectively. CR-39 samples were irradiated with 10 MeV electron beam for different durations to have the absorbed doses of 1, 10, 550, 5500, 16 500, and 55 000 kGy. From the FTIR analysis, the peak intensities at different bands were found to be changing with electron dose. A few peaks were observed to shift at high electron doses. From the UV-vis analysis, the optical band gaps for both direct and indirect transitions were found to be decreasing with the increase in electron dose whereas the opacity, number of carbon atoms in conjugation length, and the number of carbon atoms per cluster were found to be increasing. The bulk etch rate was observed to be increasing with the electron dose. The primary objective of this investigation was to study the response of CR-39 to high electron doses and to determine a suitable pre-irradiation condition. The results indicated that, the CR-39 pre-irradiated with electrons can have better sensitivity and thus can be potentially applied for neutron dosimetry.

  6. The former tests realized to a personal neutron dosemeter based on solid nuclear tracks detector; Primeras pruebas realizadas a un dosimetro personal de neutrones basado en detectores solidos de trazas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, M.E.; Tavera, L.; Balcazar, M. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Due to the increase in the use of neutron radiation a personal neutron dosemeter based on solid nuclear tracks detector (DSTN) was designed and constructed. The personal dosemeter design consists of three arrangements. The first one consists of a plastic nuclear tracks detector (LR115 or CR39) in contact with a LiF pellet. The second one is the same that above but it placed among two cadmium pellets and, the third one is formed by the alone detector without converter neither neutron absorber. The three arrangements are placed inside a plastic porta detector hermetically closed to avoid the bottom produced by environmental radon whichever both detectors (LR115 and CR39) are sensitive. In this work the former tests realized to that dosemeter are presented. (Author)

  7. Measurement of D-3He proton yield with CR-39 as a diagnostic for inertial confinement fusion experiments. Final report, 7 January 1983-30 September 1984

    International Nuclear Information System (INIS)

    Blue, T.E.; Wehring, B.W.

    1985-04-01

    The first phase of our research project has as its main goal the development of an image analysis system for Solid State Nuclear Track Detectors (SSNTD) readout. Section I, of this report is an introduction to SSNTDs and image analysis systems for automatic track counting. The development of the image analysis system is described in Section II. The development of our foil holder system is described in Section III. The performance of an image analysis system can only be judged with respect to a particular type of image which is to be analyzed. In order to insure the workability of our image analysis system in analyzing CR-39 SSNTDs, we have made an effort to improve our etching system and our etch procedure. The development of our etching system and our etch procedure is outlined in Section IV. Also included in Section IV are images of protons and alpha particle tracks for our etch procedure. The performance of our image analysis system is reported in Section V for the proton and alpha particle tracks which are reported in Section IV. Also, the performance of the image analysis system is reported for some test images

  8. CR-39 as an alpha spectrometer: analysis of the activity of a fossil from Presidente Prudente region, SP, Brazil

    International Nuclear Information System (INIS)

    Novaes, Felipe P.; Tello Saenz, Carlos A.; Balan, Ana Maria Osorio A.; Dias, Airton N.C.; Soares, Cleber J.; Oliveira, Roger D.; Barra, Beatriz C.

    2007-01-01

    In this work, CR-39 (a commercial polymer) was used as an alpha spectrometer, based on the relationship between the diameter and the trace gray scale with the energy of the incident alpha particle. A rock from Presidente Prudente region (SP, Brazil), containing a fossil, was analysed and a comparison of the activities in the areas with and without the fossil sample have been compared

  9. Accidental fast neutron dosimetry by means of plastic identity cards

    International Nuclear Information System (INIS)

    Lommler, B.; Pitt, E.; Scharmann, A.; Simmer, R.

    1991-01-01

    Identity cards designed to provide high security against falsification are often composed of polymeric compounds and a paper-like inlay containing the identifying information. This system may be considered as a fast neutron detector when certain boundary conditions, especially concerning the polymer are fulfilled. The track recording properties of the plastic envelope of a widely used identity card were investigated. Recoil tracks induced by fast neutrons were revealed by electrochemical etching in 5N NaOH in a thin cover mounted on a trick etch-resistant base. The etching parameters (etchant normality, temperature, time, field strength, frequency) were optimized to achieve maximum neutron sensitivity. The response for neutrons from a CF 252 source is about one per cent of that of the widely used CR-39 track detector material. The possible use of the identity card as an etch track detector in accidental neutron dosimetry is discussed. (author)

  10. Three dimensional photograph of electron tracks through a plastic scintillator

    CERN Document Server

    Filipenko, Mykhaylo; Hufschmidt, Patrick; Anton, Gisela; Campbell, Michael; Gleixner, Thomas; Leuchs, Gerd; Tick, Timo; Vallerga, John; Wagenpfeil, Michael; Michel, Thilo

    2014-01-01

    The reconstruction of particle trajectories makes it possible to distinguish between different types of charged particles. In the era of particle colliders and high luminosities, this was one of the key aspects for the discovery of many new particles, lately the Higgs-boson. In high-energy physics, where trajectories are rather long. large size trackers muste be used to achieve sufficient position resolution. This is not the case in low-energy particle physics experiments, where particle trajectories are very short. With current position-sensitive detection technologies it is difficult to obtain sufficient position resolution for particle identification in large sensitive volumes since all these detectors are based on the read-out of the ionization signal. This limitation is due to the diffusion of the drifting electrons. In this paper we demonstrate a "proof-of-principle" experiment for a new method for the tracking of charged particles. It takes advantage of the scintillation signal which is not affected by...

  11. Single track coincidence measurements of fluorescent and plastic nuclear track detectors in therapeutic carbon beams

    Czech Academy of Sciences Publication Activity Database

    Osinga, J. M.; Ambrožová, Iva; Pachnerová Brabcová, Kateřina; Akselrod, M. S.; Jäkel, O.; Davídková, Marie; Greilich, S.

    2014-01-01

    Roč. 9, APR (2014), P04013 ISSN 1748-0221 R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : instrumentation for heavy-ion therapy * particle tracking detectors * solid-state detectors * heavy-ion detectors * hybrid detectors Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.399, year: 2014

  12. Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

    Science.gov (United States)

    Ali, Dilawar; Butt, M. Z.; Ishtiaq, Mohsin; Waqas Khaliq, M.; Bashir, Farooq

    2016-11-01

    Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm-2. Optical, structural, and chemical properties were investigated by UV-vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm-1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of -CH2- group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm-2.

  13. Energy-dependent etching-related impacts on CR-39 alpha detection efficiency for the Rn-222 and Rn-220 decay chains

    Science.gov (United States)

    Tan, Y.; Yuan, H.; Kearfott, K. J.

    2018-04-01

    CR-39 detectors are widely used to measure environmental levels of Rn-222, Rn-220 and their progeny. Prior research reported the CR-39 detection efficiency for alpha particles from Rn-222, Rn-220 and their progeny under a variety of etching conditions. This paper provides an explanation for interesting observations included in that work, namely that the critical incidence angle decreases with the increasing particle energy and the detection efficiency for 8.78 MeV alpha particles is zero. This paper explains these phenomena from a consideration of the interaction of alpha particles with the CR-39 detectors and the physics of etching dynamics. The proposed theory provides a rationale for an approach to optimizing the etching conditions of CR-39 detector for measuring Rn-222, Rn-220 and their progenies.

  14. Changes in CR-39 proton sensitivity due to prolonged exposure to high vacuums relevant to the National Ignition Facility and OMEGA.

    Science.gov (United States)

    Manuel, M J-E; Rosenberg, M J; Sinenian, N; Rinderknecht, H; Zylstra, A B; Séguin, F H; Frenje, J; Li, C K; Petrasso, R D

    2011-09-01

    When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the ~1-9 MeV energy range. High vacuum conditions, of order 10(-5) Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than ~16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect was observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation. © 2011 American Institute of Physics

  15. Preliminary results of NAPL contamination in a disused industry in the city of Sao Paulo, Brazil, by radon evaluation with CR-39 detectors

    International Nuclear Information System (INIS)

    Mateus, Crislene; Pecequilo, Brigitte Roxana Soreanu

    2015-01-01

    Contaminated sites by NAPL (Non-Aqueous Phase-Liquids) may lead to safety risks to human health and to ecosystems, restrictions to urban development and decrease of real estate value. This work used the radon gas as an indicator for the analysis of subsurface soil gas, once this noble gas presents good solubility in a wide range of NAPL, being partially retained in the NAPL contamination. Therefore, a decrease of the activity of radon in the contaminated soil gas can be expected, due to the high capacity of partitioning of radon in NAPL, which allows that the NAPL retain part of the radon previously available in the soil pores. The survey was carried out at a disused industry, contaminated by low volatile NAPL, located at east of Sao Paulo city, in March/2015. Radon was evaluated by passive detection methodology with CR-39 solid state nuclear track detectors (SSNTD). Radon concentrations for the eight monitoring stations at non-contaminated locations in March/2015 varied from 16.4 ± 1.2 kBq.m -3 to 55 ± 4 kBq.m -3 . For the two monitoring stations assumed as contaminated locations in March/2015, radon concentrations were 1.17 ± 0.08 kBq.m -3 and 4.2 ± 0.3 kBq.m -3 , diminished in a range from 92% to 98% when compared with the results for the non-contaminated areas. (author)

  16. Semi-empirical approach for calibration of CR-39 detectors in diffusion chambers for radon measurements

    International Nuclear Information System (INIS)

    Pereyra A, P.; Lopez H, M. E.; Palacios F, D.; Sajo B, L.; Valdivia, P.

    2016-10-01

    Simulated and measured calibration of PADC detectors is given for cylindrical diffusion chambers employed in environmental radon measurements. The method is based on determining the minimum alpha energy (E min ), average critical angle (<Θ c >), and fraction of 218 Po atoms; the volume of the chamber (f 1 ), are compared to commercially available devices. Radon concentration for exposed detectors is obtained from induced track densities and the well-established calibration coefficient for NRPB monitor. Calibration coefficient of a PADC detector in a cylindrical diffusion chamber of any size is determined under the same chemical etching conditions and track analysis methodology. In this study the results of numerical examples and comparison between experimental calibration coefficients and simulation purpose made code. Results show that the developed method is applicable when uncertainties of 10% are acceptable. (Author)

  17. Semi-empirical approach for calibration of CR-39 detectors in diffusion chambers for radon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pereyra A, P.; Lopez H, M. E. [Pontificia Universidad Catolica del Peru, Av. Universitaria 1801, San Miguel Lima 32 (Peru); Palacios F, D.; Sajo B, L. [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apartado 89000 Caracas (Venezuela, Bolivarian Republic of); Valdivia, P., E-mail: ppereyr@pucp.edu.pe [Universidad Nacional de Ingenieria, Av. Tupac Amaru s/n, Rimac, Lima 25 (Peru)

    2016-10-15

    Simulated and measured calibration of PADC detectors is given for cylindrical diffusion chambers employed in environmental radon measurements. The method is based on determining the minimum alpha energy (E{sub min}), average critical angle (<Θ{sub c}>), and fraction of {sup 218}Po atoms; the volume of the chamber (f{sub 1}), are compared to commercially available devices. Radon concentration for exposed detectors is obtained from induced track densities and the well-established calibration coefficient for NRPB monitor. Calibration coefficient of a PADC detector in a cylindrical diffusion chamber of any size is determined under the same chemical etching conditions and track analysis methodology. In this study the results of numerical examples and comparison between experimental calibration coefficients and simulation purpose made code. Results show that the developed method is applicable when uncertainties of 10% are acceptable. (Author)

  18. Three-dimensional elasto-plastic soil modelling and analysis of sauropod tracks

    Directory of Open Access Journals (Sweden)

    Eugenio Sanz

    2016-06-01

    Full Text Available This paper reports the use of FEA (Finite Element Analysis to model dinosaur tracks. Satisfactory reproductions of sauropod ichnites were simulated using 3D numerical models of the elasto-plastic behaviour of soils. Though the modelling was done of ichnites in situ at the Miraflores I tracksite (Soria, Spain, the methodology could be applied to other tracksites to improve their ichnological interpretation and better understand how the type and state of the trodden sediment at the moment the track is created is a fundamental determinant of the morphology of the ichnite. The results obtained explain why the initial and commonly adopted hypothesis—that soft sediments become progressively more rigid and resistant at depth—is not appropriate at this tracksite. We explain why it is essential to consider a more rigid superficial layer (caused by desiccation overlying a softer layer that is extruded to form a displacement rim. Adult sauropods left trackways behind them. These tracks could be filled up with water due to phreatic level was close to the ground surface. The simulation provides us with a means to explain the differences between similar tracks (of different depths; with or without displacement rims in the various stratigraphic layers of the tracksite and to explain why temporary and variable conditions of humidity lead to these differences in the tracks. The simulations also demonstrate that track depth alone is insufficient to differentiate true tracks from undertracks and that other discrimination criteria need to be taken into account. The scarcity of baby sauropod tracks is explained because they are shallow and easily eroded.

  19. Plastic

    International Nuclear Information System (INIS)

    Jeong Gi Hyeon

    1987-04-01

    This book deals with plastic, which includes introduction for plastic, chemistry of high polymers, polymerization, speciality and structure of a high molecule property of plastic, molding, thermosetting plastic, such as polyethylene, polyether, polyamide and polyvinyl acetyl, thermal plastic like phenolic resins, xylene resins, melamine resin, epoxy resin, alkyd resin and poly urethan resin, new plastic like ionomer and PPS resin, synthetic laminated tape and synthetic wood, mixed materials in plastic, reprocessing of waste plastic, polymer blend, test method for plastic materials and auxiliary materials of plastic.

  20. Study of optical band gap, carbonaceous clusters and structuring in CR-39 and PET polymers irradiated by 100 MeV O 7+ ions

    Science.gov (United States)

    Ramola, R. C.; Chandra, Subhash; Negi, Ambika; Rana, J. M. S.; Annapoorni, S.; Sonkawade, R. G.; Kulriya, P. K.; Srivastava, A.

    2009-01-01

    Commercially purchased CR-39 and PET polymers were irradiated by 100 MeV O 7+ ions of varying fluences, ranging from 1×10 11 to 1×10 13 ions/cm 2. The effects of swift heavy ions (SHI) on the structural, optical and chemical properties of CR-39 and PET polymers were studied using X-ray diffraction (XRD), UV-visible spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The XRD patterns of CR-39 show that the intensity of the peak decreases with increasing ion fluence, which indicates that the semicrystalline structure of polymer changes to amorphous with increasing fluences. The XRD patterns of PET show a slight increase in the intensity of the peaks, indicating an increase in the crystallinity. The UV-visible spectra show the shift in the absorbance edge towards the higher wavelength, indicating the change in band gap. Band gap in PET and CR-39 found to be decrease from 3.87 to 2.91 and 5.3-3.5 eV, respectively. The cluster size also shows a variation in the carbon atoms per cluster that varies from 42 to 96 in CR-39 and from 78 to 139 in PET. The FTIR spectra show an overall reduction in intensity of the typical bands, indicating the degradation of polymers after irradiation.

  1. Modifications in the optical and thermal properties of a CR-39 polymeric detector induced by high doses of γ-radiation

    Science.gov (United States)

    Saad, A. F.; Ibraheim, Mona H.; Nwara, Aya M.; Kandil, S. A.

    2018-04-01

    Effects of γ-radiation on the optical and thermal properties of a poly allyl diglycol carbonate (PADC), a form of CR-39, polymer have been investigated. CR-39 detectors were exposed to γ-rays at very high doses ranging from 5.0 × 105 to 3.0 × 106 Gy. The induced changes were analyzed using ultraviolet-visible spectroscopy (UV-VIS) in absorbance mode, and thermogravimetric analysis (TGA). The UV-visible spectra of the virgin and γ-irradiated CR-39 polymer detectors displayed a significant decreasing trend in their optical energy band gaps for indirect transitions, whereas for the direct ones showed a little change. This drop in the energy band gap with increasing dose is discussed on the basis of the gamma irradiation induced modifications in the CR-39 polymeric detector. The TGA thermograms show that the weight loss rate increased with increase in dose, which may be due to the disordered system via scission followed by crosslinking in the irradiated polymer detector. The TGA thermograms also indicated that the CR-39 detector decomposed in three/four stages for the virgin and irradiated samples. The activation energy for thermal decomposition was determined using a type of Arrhenius equation based on the TGA experimental results. These experimental results so obtained can be well used in radiation dosimetry.

  2. Determination of soil gas radon concentration from some locations of Gedarif town, Sudan, by using CR-39

    Directory of Open Access Journals (Sweden)

    Elzain Abd-Elmoniem Ahmed

    2017-01-01

    Full Text Available This work presents the results of the study of radon concentration in soil gas for 187 measurements of soil samples collected from different locations of Gedarif town in Sudan using the can technique, containing CR-39. From in this work, the soil gas radon concentrations were ranged from 4.20 ± 0.61 kBqm-3 to 15.15 ± 1.62 kBqm-3 with an average of (9.10 ± 1.31 kBqm-3. The annual effective dose was calculated that ranged from 18.71 ± 2.73 mSv to 67.53 ± 7.22 mSv, with an average value of 40.57 ± 5.86 mSv. A good correlation was observed between the radon concentration and soil depth. It was found that soil radon gas concentration increased with depth. The radon concentrations in the soil samples were found to be larger than the allowed limit from the World Health Organization. The results of this work were compared with national and worldwide results.

  3. Behavioural plasticity in wintering Mediterranean ospreys revealed by stable isotopes analyses and GPS tracking.

    Science.gov (United States)

    Monti, Flavio; Robert, Aloïs; Dominici, Jean-Marie; Sforzi, Andrea; Triay Bagur, Rafel; Muñoz Navarro, Antoni; Guillou, Gaël; Bentaleb, Ilham; Duriez, Olivier

    2015-04-01

    To infer wintering ecology in Mediterranean ospreys (Pandion haliaetus) we relied on a dual and complementary approach, using both GPS tracking and multi stable isotope tracer approaches. A control sample of feathers from 80 individuals (mostly chicks) was collected over a large latitudinal gradient (from Lapland to Africa) to assess the variability of carbon, nitrogen and sulphur stable isotope ratios between breeding sites and habitat types across the Western Palearctic. Then, C, N and S isotopic compositions from an experimental set of 18 Mediterranean adults were examined to infer wintering ground locations and habitat types used during the inter-breeding period. Additionally, 12 adult ospreys were fitted with GPS devices and tracked during migration and the wintering season. By combining the two techniques we evidenced a partial migratory population with 41.7% of tagged individuals being resident and 58.3% that actually migrated. Ospreys spent the winter at temperate latitudes and showed a high plasticity in habitat selection. They made use of marine bays, coastal lagoons/marshland and inland freshwater sites. Movements and home range areas were reduced during the season. Wintering grounds were largely spread over the coasts of different countries of the basin, rather than concentrated in one single area. Such behavioural plasticity in the choice of location and habitat type suggests the implementing of broad-scale approaches for the protection of important areas for ospreys in winter. To contribute at assuring a right level of conservation of the osprey populations in the Mediterranean basin, a harmonization of the management protocols of wetland sites among countries is necessary.

  4. 3D imaging of neutron tracks using confocal microscopy

    Science.gov (United States)

    Gillmore, Gavin; Wertheim, David; Flowers, Alan

    2016-04-01

    Neutron detection and neutron flux assessment are important aspects in monitoring nuclear energy production. Neutron flux measurements can also provide information on potential biological damage from exposure. In addition to the applications for neutron measurement in nuclear energy, neutron detection has been proposed as a method of enhancing neutrino detectors and cosmic ray flux has also been assessed using ground-level neutron detectors. Solid State Nuclear Track Detectors (or SSNTDs) have been used extensively to examine cosmic rays, long-lived radioactive elements, radon concentrations in buildings and the age of geological samples. Passive SSNTDs consisting of a CR-39 plastic are commonly used to measure radon because they respond to incident charged particles such as alpha particles from radon gas in air. They have a large dynamic range and a linear flux response. We have previously applied confocal microscopy to obtain 3D images of alpha particle tracks in SSNTDs from radon track monitoring (1). As a charged particle traverses through the polymer it creates an ionisation trail along its path. The trail or track is normally enhanced by chemical etching to better expose radiation damage, as the damaged area is more sensitive to the etchant than the bulk material. Particle tracks in CR-39 are usually assessed using 2D optical microscopy. In this study 6 detectors were examined using an Olympus OLS4100 LEXT 3D laser scanning confocal microscope (Olympus Corporation, Japan). The detectors had been etched for 2 hours 50 minutes at 85 °C in 6.25M NaOH. Post etch the plastics had been treated with a 10 minute immersion in a 2% acetic acid stop bath, followed by rinsing in deionised water. The detectors examined had been irradiated with a 2mSv neutron dose from an Am(Be) neutron source (producing roughly 20 tracks per mm2). We were able to successfully acquire 3D images of neutron tracks in the detectors studied. The range of track diameter observed was between 4

  5. Semi-automated, three-dimensional measurement of etched tracks in solid-state nuclear track detectors

    International Nuclear Information System (INIS)

    Price, P.B.; Krischer, W.

    1985-01-01

    We describe a new method for measuring the shapes and sizes of etched tracks in plastic or glass detectors, using a commercial digital image processing system. The method exploits the fact that in transmitted light any portion of the microscopic image of the track is in best focus when it is darkest. A minimization algorithm is used to produce a two-dimensional projected image of the three-dimensional etched track. The locus of points of maximum gradients in the image leads to a closed contour of the projected image. From this gradient image the profile, length and width of the conical etched track are automatically determined. The method is also applicable (a) to a track that penetrates a detector and has been etched until the cones from opposite surfaces are connected and (b) to a track with a curved profile due to a strongly slowing particle. The method is illustrated with measurements of tracks of 1 A GeV uranium ions in Tuffak polycarbonate and in CR-73 polycarbonate and of cosmic ray tracks in a CR-39 detector. (orig.)

  6. Fatigue crack monitoring in train track steel structures using plastic optical fiber sensor

    Science.gov (United States)

    Yang, D.; Li, D.; Kuang, K. S. C.

    2017-10-01

    Plastic optical fiber (POF) sensors have shown excellent potential for damage detection and structural health monitoring in a variety of engineering structures. This paper discusses the feasibility of using POF sensors in conjunction with a signal-processing algorithm capable of detecting and monitoring fatigue-induced cracks in train track steel structures in real time. The POF sensor, which was modified from an existing design to increase the signal sensitivity, allows for accurate detection of a fatigue crack developed in a specimen, and was found to compare well to the reference acoustic emission (AE) sensors and crack opening displacement (COD) gauge attached to the specimen. The crack-detection technique, which relies on capturing the intensity variation of the POF sensor, was not susceptible to any signal fluctuations commonly associated with intensity-based optical fiber sensors. The results show that the technique has potential for use in detecting the initiation and propagation of specific segments of a structure vulnerable to cracking due to external cyclic loading, e.g. at welded joints in train tracks under train loads or offshore structures subject to wave loads. The POF sensor system is composed of inexpensive parts (LED light source, photodetectors, and data acquisition units) and can easily be installed to the host structure. To validate the proposed damage-detection technique, the instrumented specimens are subjected to cyclic loading in order to induce stable crack propagation in the specimen. A COD gauge and AE were used for the purpose of calibration and comparison. The results show remarkable resemblance in terms of crack initiation and propagation identification exhibited by all three types of sensors, highlighting the potential of the proposed sensor for crack initiation detection and subsequent monitoring of crack propagation.

  7. Plastics

    OpenAIRE

    Cassou, Emilie

    2018-01-01

    Although the agricultural sector is not the largest user of plastics, their rapid appearance on farms the world over is quietly turning into a substantial pollution concern. Versatile and economical as they are, plastics are found all over farms. From machines to mulches, they are the stuff of bags and tubs, of tubes and tools, of tags and trays, and of pots and twine. Plastic films are us...

  8. Measurement of LET (linear energy transfer) spectra using CR-39 at different depths of water irradiated by 171 MeV protons: A comparison with Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, G.S. [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tripathy, S.P., E-mail: sam.tripathy@gmail.com [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Homi Bhabha National Institute, Mumbai 400094 (India); Molokanov, A.G.; Aleynikov, V.E. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Sharma, S.D. [Homi Bhabha National Institute, Mumbai 400094 (India); Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Bandyopadhyay, T. [Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Homi Bhabha National Institute, Mumbai 400094 (India)

    2016-05-11

    In this work, we have used CR-39 detectors to estimate the LET (linear energy transfer) spectrum of secondary particles due to 171 MeV proton beam at different depths of water including the Bragg peak region. The measured LET spectra were compared with those obtained from FLUKA Monte Carlo simulation. The absorbed dose (D{sub LET}), dose equivalent (H{sub LET}) were estimated using the LET spectra. The values of D{sub LET} and H{sub LET} per incident proton fluence were found to increase with the increase in depth of water and were maximum at Bragg peak. - Highlights: • Measurement of LET spectrometry using CR-39 detectors at different depths of water. • Comparison of measured spectra with FLUKA Monte carlo simulation. • Absorbed dose and dose equivalent was found to increase with depth of water.

  9. A study on measurement of neutrons generated in radiation therapy – Measurement of neurons in CR-39 detection method

    International Nuclear Information System (INIS)

    Park, Cheol-Soo; Cho, Jae-Hwan; Lee, Hae-Kag; Lee, Sun-Yeob; Jang, Hyon-Chol; Dong, Kyung-Rae; Chung, Woon-Kwan; Jin, Lee; Moon, Deog-Hwan; Lee, Kwang-Sung; Yang, Nam-Oh; Cho, Moo-Seong

    2013-01-01

    Highlights: ► To measure the neutrons generated in a linear accelerator. ► Both fast neutrons and thermal neutrons produced an increase in the dose of neutrons generated with increasing irradiation dose. ► The generation of neutrons increased when a wedge filter was used. ► When the SRS cone that required a high dose was used, more neutrons were detected. -- Abstract: The CR-39 [diethylene glycol bis-(allylcarbonate)] neuron detection method was used to measure the dose of neutrons generated in X-ray (photon) therapy conducted in a linear accelerator, and to use high-energy photons as part of the clinical applications to examine the problems associated with the dose for patients caused by the generation of neutrons from high-energy photons used for cancer therapy. According to the experimental results, 0.35 mSv, 0.65 mSv 1.82 mSv of fast neutrons on average were generated from 1 Gy, 2 Gy and 5 Gy of photon irradiation, respectively, whereas 0.26 mSv, 0.56 mSv and 1.23 mSv of thermal neutrons were generated. Both fast neutrons and thermal neutrons produced an increase in the dose of neutrons generated with increasing irradiation dose. With in regard to the dose generated within and around the irradiation area of the photon rays, it was confirmed that more neutrons were generated within the irradiation area. A wedge filer was used to measure the generation of neutrons. According to the measurement results, the generation of neutrons increased when a wedge filter was used. When the SRS cone that required a high dose was used, more neutrons were detected than those in the previous experiment. When fast neutrons were used, 2.85 mSv neutrons on average were generated from 5 Gy of photon irradiation. When thermal neutrons were used, 1.37 mSv neutrons on average were generated from 5 Gy of photon irradiation. Overall, approximately 1.6 times and 1.12 times more fast and thermal neutrons, respectively, were generated than in the case of a general treatment with 5 Gy

  10. Temperature effects on radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    Mendoza A, D.

    1996-01-01

    The objective of present work was to study the temperature effect on radiation damage registration in the structure of a Solid State Nuclear Track Detector of the type CR-39. In order to study the radiation damage as a function of irradiation temperature, sheets of CR-39 detectors were irradiated with electron beams, simulating the interaction of positive ions. CR-39 detectors were maintained at a constant temperature from room temperature up to 373 K during irradiation. Two techniques were used from analyzing changes in the detector structure: Electronic Paramagnetic Resonance (EPR) and Infrared Spectroscopy (IR). It was found by EPR analysis that the amount of free radicals decrease as irradiation temperature increases. The IR spectrums show yield of new functional group identified as an hydroxyl group (OH). A proposed model of interaction of radiation with CR-39 detectors is discussed. (Author)

  11. Cosmic radiation monitoring at low-Earth orbit by means of thermoluminescence and plastic nuclear track detectors

    Czech Academy of Sciences Publication Activity Database

    Ambrožová, Iva; Pachnerová Brabcová, Kateřina; Kubančák, Ján; Šlegl, Jakub; Tolochek, R. V.; Ivanova, O. A.; Shurshakov, V. A.

    2017-01-01

    Roč. 106, č. 12 (2017), s. 262-266 ISSN 1350-4487 R&D Projects: GA ČR GJ15-16622Y Institutional support: RVO:61389005 Keywords : BION-M1 * cosmic radiation * low earth orbit * passive detector * thermoluminescent detector * plastic nuclear track detector Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.442, year: 2016

  12. Neutron activation and track analysis of the newly found bones of the southern mammoths and dinosaurs

    International Nuclear Information System (INIS)

    Vasidov, A.; Osinskaya, N.S.; Saidullaev, B.J.; Akhmadshaev, A.

    2016-01-01

    The bones of southern mammoths and dinosaur had been discovered in the territory of Uzbekistan in 2005-2014. The main aim of the work was a study of profiles of radiogenic and some of elements in bones of mammoths and dinosaur, and the element comparisons with standard bones and its soils by instrumental neutron activation and track analysis. In bones of the mammoths and dinosaur were registered a high contents of uranium and rare earth elements by instrumental neutron activation analysis. The radon concentrations in samples were measured in isolated plastic chambers by solid state nuclear track detectors type of CR-39 within 35 days. The values of radon exhalation rates were determined very more in ancient bones than in standard bones and soils. (author)

  13. Calibration of detectors type CR-39 for methodology implementation for Radon-222 determination in CRCN-NE, Brazil; Calibração de detectores do tipo CR-39 para implementação da metodologia de determinação de radônio-222 no CRCN-NE

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Karolayne E.M. da; Santos, Mariana L. de O.; Amaral, Déric S. do; Vilela, Eldice C.; França, Elvis J. de; Hazin, Clovis A.; Farias, Emerson E.G. de, E-mail: keesthefany@gmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: dericsoares@gmail.com, E-mail: ecvilela@cnen.gov.br, E-mail: ejfrana@cnen.gov.br, E-mail: chazin@cnen.gov.br, E-mail: emersonemiliamo@yahoo.com.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2017-07-01

    Radon-222 is a radioactive gas, a product of the decay of uranium-238, which emits alpha particles and represents more than 50% of the dose of natural radiation received by the population. Therefore, monitoring of this gas is essential. For indoor measurement, solid state detectors can be used, the most common of which is CR-39. For monitoring using CR-39, alpha particles, generated by radon-222 and the daughter radionuclides, strike the surface of the detector and generate traces. To relate the trace density per exposure area in environments with unknown activity concentration, it is necessary to determine the calibration factor. The objective of this study was to calibrate CR-39 type detectors for the implementation of the radon determination methodology in Centro Regional de Ciencias Nucleares do Nordeste - CRCN-NE of Brazilian Nuclear Energy Commission - CNEN. In order to determine the CR-39 calibration factor, 19 exposures of the detectors were performed in the CRCN-NE calibration chamber (RN1-CRCN) at an activity of 5.00 kBq m{sup -3}, with the exposure time varying from 24 to 850 hours. For the detection of the detectors, sodium hydroxide was used in a thermostat bath at 90 ° C for 5 hours. The count of number of traits per unit of field was performed with the aid of optical microscopy with an increase of 100 times, being read 30 fields per dosimeters. As a result, the calibration factor was obtained, and the linear response of the trace density as a function of exposure was observed. The results allow the use of CR-39 in the determination of radon-222 by CRCN-NE.

  14. Diffraction-amalgamated grain boundary tracking for mapping 3D crystallographic orientation and strain fields during plastic deformation

    International Nuclear Information System (INIS)

    Toda, Hiroyuki; Kamiko, Takanobu; Tanabe, Yasuto; Kobayashi, Masakazu; Leclere, D.J.; Uesugi, Kentaro; Takeuchi, Akihisa; Hirayama, Kyosuke

    2016-01-01

    By amalgamating the X-ray diffraction technique with the grain boundary tracking technique, a novel method, diffraction-amalgamated grain boundary tracking (DAGT), has been developed. DAGT is a non-destructive in-situ analysis technique for characterising bulk materials, which can be applied up to near the point of fracture. It provides information about local crystal orientations and detailed grain morphologies in three dimensions, together with high-density strain mapping inside grains. As it obtains the grain morphologies by utilising X-ray imaging instead of X-ray diffraction, which latter is typically vulnerable to plastic deformation, DAGT is a fairly robust technique for analysing plastically deforming materials. Texture evolution and localised deformation behaviours have here been successfully characterised in Al–Cu alloys, during tensile deformation of 27% in applied strain. The characteristic rotation behaviours of grains were identified, and attributed to the effects of interaction with adjacent grains on the basis of the 3D local orientation and plastic strain distributions. It has also been revealed that 3D strain distribution in grains is highly heterogeneous, which is not explained by known mechanisms such as simple incompatibility with adjacent grains or strain percolation through soft grains. It has been clarified that groups consisting of a few adjacent grains may deform coordinately, especially in shear and lateral deformation, and the characteristic deformation pattern is thereby formed on a mesoscopic scale.

  15. Nuclear track detection using thermoset polycarbonates derived from pentaerythritol

    Energy Technology Data Exchange (ETDEWEB)

    Mandrekar, Vinod K. [Department of Chemistry, Goa University, Goa-403 206 (India); Chourasiya, G. [M P and T Section, Radiological Physics and Advisory Division, Bhabha Atomic Research Center, Mumbai-400 085 (India); Kalsi, P.C. [Radiochemistry Division, Bhabha Atomic Research Center, Mumbai-400 085 (India); Tilve, S.G. [Department of Chemistry, Goa University, Goa-403 206 (India); Nadkarni, V.S., E-mail: nitin@unigoa.ac.i [Department of Chemistry, Goa University, Goa-403 206 (India)

    2010-03-01

    The paper describes the synthesis and performance of two polymers as nuclear track detectors, both having alpha sensitivity higher than that of the widely-used polymer CR-39. A homopolymer (PPETAC) from pentaerythritol tetrakis(allyl carbonate) (PETAC) monomer and its various copolymers with allyl diglycol carbonate (ADC) prepared by cast polymerization were successfully used as nuclear track detectors. The copolymer PETAC:ADC 4:6 weight percent shows maximum alpha sensitivity, almost double that of CR-39 under identical experimental conditions. This copolymer can reveal alpha particle tracks from {sup 239}Pu source in about 60 min and {sup 252}Cf fission fragment tracks by chemical etching in less than 30 min, compared to about 120 min and 45 min respectively, required by CR-39. The polymers can be conveniently etched using aqueous sodium hydroxide.

  16. Nuclear track detection using thermoset polycarbonates derived from pentaerythritol

    International Nuclear Information System (INIS)

    Mandrekar, Vinod K.; Chourasiya, G.; Kalsi, P.C.; Tilve, S.G.; Nadkarni, V.S.

    2010-01-01

    The paper describes the synthesis and performance of two polymers as nuclear track detectors, both having alpha sensitivity higher than that of the widely-used polymer CR-39. A homopolymer (PPETAC) from pentaerythritol tetrakis(allyl carbonate) (PETAC) monomer and its various copolymers with allyl diglycol carbonate (ADC) prepared by cast polymerization were successfully used as nuclear track detectors. The copolymer PETAC:ADC 4:6 weight percent shows maximum alpha sensitivity, almost double that of CR-39 under identical experimental conditions. This copolymer can reveal alpha particle tracks from 239 Pu source in about 60 min and 252 Cf fission fragment tracks by chemical etching in less than 30 min, compared to about 120 min and 45 min respectively, required by CR-39. The polymers can be conveniently etched using aqueous sodium hydroxide.

  17. Effect of environmental conditions on radon concentration-track ...

    Indian Academy of Sciences (India)

    Abstract. In this work, the effect of environmental conditions viz., temperature (Т) and relative humidity (RH) on the track density-radon concentrations calibration factor (K) has been studied for CR-39 and LR-115 track detectors. The factor K was determined using a reference radon chamber in the National Institute for ...

  18. Investigation of alpha emitters in fresh and powdered blood of fertile women: an in vitro application of CR-39 NTDs

    International Nuclear Information System (INIS)

    Salih, N.F.; University of Koya, Kurdistan; Jaafar, M.S.

    2014-01-01

    Blood samples were acquired from 60 women aged 20-44 years having decreased fertility, infertile or with uterine tumors in the Iraqi Kurdistan region. The concentrations of α emitters in fresh blood ranged from 0.0029 to 0.0088 ppm, whereas those in powdered blood ranged from 0.0036 ppm in Eiskan to 0.0096 ppm in Halabjay-Kon in Sulaymania. The α emitter concentrations in fresh blood ranged from 0.0029 to 0.0139 ppm, whereas those in powdered blood ranged from 0.0031 ppm in Shorsh to 0.0146 ppm in Sedakan in the Erbil Governorate. However, the concentrations of α emitters in the blood of women with decreased fertility were higher in the North than women from South Iraq. The difference significantly p < 0.001 revealed higher means of track density of fresh and powder blood in Erbil compared to Sulaymania. α are more damaging to the living tissue and exposure of the gonads leads to decreased fertility in women, most of data have been significant therefore, the result shown the radiation effect on women fertility. (author)

  19. Neutron irradiations of proton-sensitive track etch detectors: Results of the joint European/USA/Canadian irradiations organized by EURADOS-CENDOS (1986)

    International Nuclear Information System (INIS)

    Piesch, E.

    1987-09-01

    In 1986, the EURADOS-CENDOS group organized a joint neutron irradiation of proton-sensitive track etch detectors particularly CR-39 and CN-85. The purpose of this experiment was to investigate the energy response and the background track density of plastics under development for use as personnel neutron dosemeters. Dosemeters from 13 laboratories in the European Communities, the USA and Canada were sent to five laboratories and irradiated with monoenergetic neutrons of 144 keV, 250 keV, 570 keV, 1.2 MeV, 5.3 MeV, 14.7 MeV, and with Cf-252 neutrons, in the dose equivalent range between 1.5 mSv and 4.2 mSv. The report consists of short papers from each participant giving a description of the dosemeter used, the processing and evaluation method employed and a discussion of the measurement results. (orig.) [de

  20. Three-dimensional photograph of electron tracks through a plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Filipenko, Mykhaylo; Hufschmidt, Patrick; Anton, Gisela; Gleixner, Thomas; Wagenpfeil, Michael; Michel, Thilo [University of Erlangen-Nuremberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Iskhakov, Timur; Leuchs, Gerd [Max-Planck Institute for the Science of Light, Erlangen (Germany); Campbell, Michael; Tick, Timo [European Organization for Nuclear Research, CERN, Geneve 23 (Switzerland); Vallerga, John [University of California, Experimental Astrophysics Group, Space Science Laboratory, Berkeley, CA (United States)

    2014-11-15

    The reconstruction of particle trajectories makes it possible to distinguish between different types of charged particles. In high-energy physics, where trajectories are rather long (several meters), large size trackers must be used to achieve sufficient position resolution. However, in low-background experiments like the search for neutrinoless double beta decay, tracks are rather short (some mm to several cm, depending on the detector in use) and three-dimensional trajectories could only be resolved in gaseous time-projection chambers so far. For detectors of a large volume of around one cubic meter (large in the scope of neutrinoless double beta search) and therefore large drift distances (several decimeters to 1 m), this technique is limited by diffusion and repulsion of charge carriers. In this work we present a ''proof-of-principle'' experiment for a new method of the three-dimensional tracking of charged particles by scintillation light: we used a setup consisting of a scintillator, mirrors, lenses, and a novel imaging device (the hybrid photon detector) in order to image two projections of electron tracks through the scintillator. We took data at the T-22 beamline at DESY with relativistic electrons with a kinetic energy of 5 GeV and from this data successfully reconstructed their three-dimensional propagation path in the scintillator. With our setup we achieved a position resolution in the range of 170-248 μm. (orig.)

  1. [Dosimetry of fast neutrons in 1W nuclear reactor with plastic nuclear-track detectors].

    Science.gov (United States)

    Yasubuchi, S; Hoshi, M; Itoh, T; Hisanaga, S; Niwa, T; Miki, R; Kondo, S

    1989-09-01

    A nuclear reactor at Kinki University is operated at the maximum of 1W. It produces fission neutrons as much as gamma-rays. To facilitate its use for neutron radiobiology, fast neutrons inside the reactor were measured with nuclear-track detectors TS 16 N and a pair of ion chambers. The angular dependence of TS 16 N response, an anisotropy of fast neutron fluxes in the reactor and misuse of the kerma factor assumed for radiation protection business are the major causes of discrepancy is measured doses by the two methods. Correction factors for the three causes are proposed. After correction, neutron doses estimated with TS 16 N and chambers agree within 5%. The dose-rate at the reactor's center is about 20 tissue-cGy/h. This is the first in situ dosimetry of fast neutrons in a reactor with track detectors attached to biologic samples. Our routine usage has demonstrated that, if used with caution, TS 16 N elements are handy, reliable monitors for fast neutron dosimetry as they are insensitive to contaminated gamma-rays and small enough to be attached to biologic samples.

  2. Theoretical determination of the neutron detection efficiency of plastic track detectors. Pt. 1

    International Nuclear Information System (INIS)

    Pretzsch, G.

    1982-01-01

    A theoretical model to determine the neutron detection efficiency of organic solid state nuclear track detectors without external radiator is described. The model involves the following calculation steps: production of heavy charged particles within the detector volume, characterization of the charged particles by appropriate physical quantities, application of suitable registration criteria, formation of etch pits. The etch pits formed are described by means of a distribution function which is doubly differential in both diameter and depth of the etch pits. The distribution function serves as the input value for the calculation of the detection efficiency. The detection efficiency is defined as the measured effect per neutron fluence. Hence it depends on the evaluation technique considered. The calculation of the distribution function is carried out for cellulose triacetate. The determination of the concrete detection efficiency using the light microscope and light transmission measurements as the evaluation technique will be described in further publications. (orig.)

  3. Tracking Plasticity: Effects of Long-Term Rehearsal in Expert Dancers Encoding Music to Movement

    Science.gov (United States)

    Bar, Rachel J.; DeSouza, Joseph F. X.

    2016-01-01

    Our knowledge of neural plasticity suggests that neural networks show adaptation to environmental and intrinsic change. In particular, studies investigating the neuroplastic changes associated with learning and practicing motor tasks have shown that practicing such tasks results in an increase in neural activation in several specific brain regions. However, studies comparing experts and non-experts suggest that experts employ less neuronal activation than non-experts when performing a familiar motor task. Here, we aimed to determine the long-term changes in neural networks associated with learning a new dance in professional ballet dancers over 34 weeks. Subjects visualized dance movements to music while undergoing fMRI scanning at four time points over 34-weeks. Results demonstrated that initial learning and performance at seven weeks led to increases in activation in cortical regions during visualization compared to the first week. However, at 34 weeks, the cortical networks showed reduced activation compared to week seven. Specifically, motor learning and performance over the 34 weeks showed the typical inverted-U-shaped function of learning. Further, our result demonstrate that learning of a motor sequence of dance movements to music in the real world can be visualized by expert dancers using fMRI and capture highly significant modeled fits of the brain network variance of BOLD signals from early learning to expert level performance. PMID:26824475

  4. Tracking Plasticity: Effects of Long-Term Rehearsal in Expert Dancers Encoding Music to Movement.

    Science.gov (United States)

    Bar, Rachel J; DeSouza, Joseph F X

    2016-01-01

    Our knowledge of neural plasticity suggests that neural networks show adaptation to environmental and intrinsic change. In particular, studies investigating the neuroplastic changes associated with learning and practicing motor tasks have shown that practicing such tasks results in an increase in neural activation in several specific brain regions. However, studies comparing experts and non-experts suggest that experts employ less neuronal activation than non-experts when performing a familiar motor task. Here, we aimed to determine the long-term changes in neural networks associated with learning a new dance in professional ballet dancers over 34 weeks. Subjects visualized dance movements to music while undergoing fMRI scanning at four time points over 34-weeks. Results demonstrated that initial learning and performance at seven weeks led to increases in activation in cortical regions during visualization compared to the first week. However, at 34 weeks, the cortical networks showed reduced activation compared to week seven. Specifically, motor learning and performance over the 34 weeks showed the typical inverted-U-shaped function of learning. Further, our result demonstrate that learning of a motor sequence of dance movements to music in the real world can be visualized by expert dancers using fMRI and capture highly significant modeled fits of the brain network variance of BOLD signals from early learning to expert level performance.

  5. Tracking Plasticity: Effects of Long-Term Rehearsal in Expert Dancers Encoding Music to Movement.

    Directory of Open Access Journals (Sweden)

    Rachel J Bar

    Full Text Available Our knowledge of neural plasticity suggests that neural networks show adaptation to environmental and intrinsic change. In particular, studies investigating the neuroplastic changes associated with learning and practicing motor tasks have shown that practicing such tasks results in an increase in neural activation in several specific brain regions. However, studies comparing experts and non-experts suggest that experts employ less neuronal activation than non-experts when performing a familiar motor task. Here, we aimed to determine the long-term changes in neural networks associated with learning a new dance in professional ballet dancers over 34 weeks. Subjects visualized dance movements to music while undergoing fMRI scanning at four time points over 34-weeks. Results demonstrated that initial learning and performance at seven weeks led to increases in activation in cortical regions during visualization compared to the first week. However, at 34 weeks, the cortical networks showed reduced activation compared to week seven. Specifically, motor learning and performance over the 34 weeks showed the typical inverted-U-shaped function of learning. Further, our result demonstrate that learning of a motor sequence of dance movements to music in the real world can be visualized by expert dancers using fMRI and capture highly significant modeled fits of the brain network variance of BOLD signals from early learning to expert level performance.

  6. Determination of boron in aqueous solutions by solid state nuclear track detectors technique, using a filtered neutron beam

    International Nuclear Information System (INIS)

    Moraes, M.A.P.V. de; Pugliesi, R.; Khouri, M.T.F.C.

    1985-11-01

    The solid state nuclear track detectors technique has been used for determination of boron in aqueous solutions, using a filtered neutron beam. The particles tracks from the 10 B(n,α)Li 7 reaction were registered in the CR-39 film, chemically etched in a (30%) KOH solution 70 0 C during 90 minutes. The obtained results showed the usefulness of this technique for boron determination in the ppm range. The inferior detectable limit was 9 ppm. The combined track registration efficiency factor K has been evaluated in the solutions, for the CR-39 detector and its values is K= (4,60 - + 0,06). 10 -4 cm. (Author) [pt

  7. Solid state nuclear track detectors in the measurement of alpha to fission branching ratios of heavy actinides

    International Nuclear Information System (INIS)

    Pandey, A.K.; Sharma, R.C.; Padalkar, S.K.; Kalsi, P.C.; Iyer, R.H.

    1992-01-01

    A sequential etching procedure for revelation of alpha and fission tracks in CR-39 was developed and optimized. Using this technique alpha and fission tracks can be differentiated unambiguously because of significant differences in their sizes and etching times. This registration and revelation procedure for alpha and fission tracks may be used for the studies of half lives, alpha to fission branching ratios and identification of radionuclides based on their decay schemes. It has the added advantage that both alpha decay and fission events can be studied using one detector and hence uncertainties related to efficiency, registration geometry, registration times, amount of radionuclides etc can be eliminated or minimized. The effects of neutron, gamma and alpha radiations on the alpha and fission fragment tracks registration and revelation properties of CR-39 detectors [CR-39, CR-39 (DOP)] were also studied. The IR spectra were also studied to find out the nature of chemical changes produced by these radiations on CR-39. (author). 32 refs., 7 figs., 4 tabs

  8. Preliminary study on 2-dimensional distributions of 10B reaction rate in a water phantom with boron-doped CR-39 for 7Li(p, n)7Be neutrons by 1.95 MeV protons

    International Nuclear Information System (INIS)

    Hasegawa, Y.; Tanaka, K.; Tsuruta, T.

    2000-01-01

    In an Accelerator-based neutron irradiation field using 7 Li(p, n) 7 Be neutrons by 1.95 MeV protons, the distributions of 10 B reaction rates and thermal neutron fluence in a water phantom were measured using Boron-doped CR-39 and Au activation analysis, respectively. Comparing the results of the measurements, we discussed the validity of the evaluation method of 10 B reaction rate using thermal neutron fluence. (author)

  9. Tracking the origins of plastic debris across the Coral Sea: A case study from the Ouvéa Island, New Caledonia.

    Science.gov (United States)

    Maes, Christophe; Blanke, Bruno

    2015-08-15

    Contamination of the marine environment by human-made plastic litter is a growing and global problem. Our study attempts to explain the presence of two plastic bottles beached on the Ouvéa Island, in the southwest Pacific Ocean, with trademarks from the Solomon Islands and Papua New Guinea (PNG). We simulate the oceanic drift tracks and associated transit times with a Lagrangian interpretation of the surface currents of a high-resolution ocean model. Our results show that it takes less than 2-3months for drifting objects to connect these archipelagos (New Caledonia, Solomon Islands and PNG) and highlight the role of the meridional component of the circulation rather than the dominant zonal jets. This study shows that the origin or traceability of trash represent valuable information that can be used to test and, ultimately, improve our understanding of ocean circulation. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Development of image capture system of fission tracks in plastic detectors; Desenvolvimento de sistema de captura de imagens de tracos nucleares em detectores plasticos

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Elder M. de; Melo, Vicente P. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil). Dept. de Protecao Radiologica Ambiental

    2001-07-01

    Plastic detectors are appropriate for detection and registration of alpha particles and fission products. The interaction of these particles with the detector damage its molecular structure, leading to a latent track (visible only under an electronic microscope) with diameter in the nanometer magnitude order. There are two etching methods: the conventional and the electrochemistry one. In the conventional etching the usual conditions is to attack with NaOH 6M, producing a track of average diameter of 3 {mu} m. In the electrochemistry etching the diameter is {approx} 150 {mu}m. The aim of this work is to show the functionality of the scanner for the acquisition of these images in conditions of electrochemistry etching. We employed the following attack solution: KOH/C{sub 2}H{sub 5}OH 15% p/v, pre-etching of 30 minutes, etching with tension of 1000 V, frequency of 100 Hz, during an hour and another stage of an hour, with frequency of 8 kHz. The images were acquired with optical resolution of 400 dpi and amplification of 300%, what allows printing in paper or counting and observation of the tracks in the screen. Results have shown that the replacement of the conventional system by a scanner computer device can be performed without loss of reliability of confidence in the tracks measurement and observation. (author)

  11. Etching Properties of Poly ethyleneterephthalate (PET) Melinex-E Nuclear Track Detectors (NTDs)

    International Nuclear Information System (INIS)

    Ghanim, E.H.; Hussein, A.; El-samman, H.M.; Tretyakova, S.P.

    2009-01-01

    One of the main parameters that control track formation is the bulk etch rate, VB. The dependence of VB on etchant concentrations and temperatures was extensively carried out. It is found that, VB of the PET Melinex-E (C 10 H 8 O 4 ) depends upon the etchant temperature T through an Arrhenius equation. While, the dependence of VB on the etchant concentration; C followed the relation VB = A C n. The activation energy of etching, Eb, for the studied Melinex-E detector was calculated. An average value of Eb = 0.83 ± 0.03 eV was extracted. The variation of, VB, of PET with etching duration was studied and compared with that of CR-39 plastic at certain etching temperature; T e =60 degree C and at different etchant concentrations. The irradiation facilities were performed with the 252 Cf fission fragments and 129 Xe +8 (θi =π/2). Results of these studies were discussed in the frame work of nuclear track formation and etching theories

  12. Development of a model using the MATLAB System identification toolbox to estimate (222)Rn equilibrium factor from CR-39 based passive measurements.

    Science.gov (United States)

    Abo-Elmagd, M; Sadek, A M

    2014-12-01

    Can and Bare method is a widely used passive method for measuring the equilibrium factor F through the determination of the track density ratio between bare (D) and filtered (Do) detectors. The dimensions of the used diffusion chamber are altering the deposition ratios of Po-isotopes on the chamber walls as well as the ratios of the existing alpha emitters in air. Then the measured filtered track density and therefore the resultant equilibrium factor is changed according to the diffusion chamber dimensions. For this reason, high uncertainty was expected in the measured F using different diffusion chambers. In the present work, F is derived as a function of both track density ratio (D/Do) and the dimensions of the used diffusion chambers (its volume to the total internal surface area; V/A). The accuracy of the derived formula was verified using the black-box modeling technique via the MATLAB System identification toolbox. The results show that the uncertainty of the calculated F by using the derived formula of F (D/Do, V/A) is only 5%. The obtained uncertainty ensures the quality of the derived function to calculate F using diffusion chambers with wide range of dimensions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. New polymers for nuclear track detection

    International Nuclear Information System (INIS)

    Mascarenhas, Adlete A.A.; Tilve, S.G.; Nadkarni, V.S.

    2004-01-01

    Polymeric track detectors of higher sensitivity were developed from a novel monomer, called NADAC, prepared from diethanolamine. NADAC was homopolymerised using peroxydicarbonate initiators by the radical catalyzed bulk polymerization using an indigenously designed mold to give a 500-micron thick polymer film, henceforth referred to as PNADAC. Also a copolymer of NADAC and ADC monomer has been prepared in a similar way. The above materials were used for recording autoradiographs of 23 '9Pu alpha particles source and also for 252 Cf fission fragment detection. The etching parameters of the newly developed films have been compared with that of the commercially available CR-39 track detector. (author)

  14. Influence of tracks densities in solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Guedes O, S.; Hadler N.; Lunes, P.; Saenz T, C.

    1996-01-01

    When Solid State Nuclear Track Detectors (SSNTD) is employed to measure nuclear tracks produced mainly by fission fragments and alpha particles, it is considered that the tracks observation work is performed under an efficiency, ε 0 , which is independent of the track density (number of tracks/area unit). There are not published results or experimental data supporting such an assumption. In this work the dependence of ε 0 with track density is studied basing on experimental data. To perform this, pieces of CR-39 cut from a sole 'mother sheet' were coupled to thin uranium films for different exposition times and the resulting ratios between track density and exposition time were compared. Our results indicate that ε 0 is constant for track densities between 10 3 and 10 5 cm -2 . At our etching conditions track overlapping makes impossible the counting for densities around 1.7 x 10 5 cm -2 . For track densities less than 10 3 cm -2 , ε 0 , was not observed to be constant. (authors). 4 refs., 2 figs

  15. Nuclear Track Detectors. Searches for Exotic Particles

    CERN Document Server

    Giacomelli, Giorgio

    2008-01-01

    We used Nuclear Track Detectors (NTD) CR39 and Makrofol for many purposes: i) Exposures at the SPS and at lower energy accelerator heavy ion beams for calibration purposes and for fragmentation studies. ii) Searches for GUT and Intermediate Mass Magnetic Monopoles (IMM), nuclearites, Q-balls and strangelets in the cosmic radiation. The MACRO experiment in the Gran Sasso underground lab, with ~1000 m^2 of CR39 detectors (plus scintillators and streamer tubes), established an upper limit for superheavy GUT poles at the level of 1.4x10^-16 cm^-2 s^-1 sr^-1 for 4x10^-5 CR39 detectors exposed for 4.22 y, gave an upper limit for IMMs of ~1.3x10^-15 cm^-2 s^-1 sr^-1. The experiments yielded interesting upper limits also on the fluxes of the other mentioned exotic particles. iii) Environmental studies, radiation monitoring, neutron dosimetry.

  16. Secondary ion mass spectrometry combined with alpha track detection for isotope abundance ratio analysis of individual uranium-bearing particles.

    Science.gov (United States)

    Esaka, Fumitaka; Magara, Masaaki

    2014-03-01

    Secondary ion mass spectrometry (SIMS) was used in combination with alpha track detection for the efficient analysis of uranium-bearing particles with higher (235)U abundances in environmental samples. A polycarbonate film containing particles was prepared and placed in contact with a CR-39 plastic detector. After exposure for 28 days, the detector was etched in a NaOH solution and each uranium-bearing particle was identified through observation of the alpha tracks recorded in the detector. A portion of the film containing each uranium-bearing particle was cut out and put onto a glassy carbon planchet. The films on the planchet were decomposed through plasma ashing for subsequent uranium abundance ratio analysis with SIMS. The alpha track-SIMS analysis of 10 uranium-bearing particles in a sample taken from a nuclear facility enabled n((235)U)/n((238)U) abundance ratios in the range 0.0072-0.25 to be detected, which were significantly higher than those obtained by SIMS without alpha track detection. The duration of the whole analytical process for analysis of 10 particles was about 32 days. The detection efficiency was calculated to be 27.1±6.5%, based on the analysis of the particles in uranium reference materials. The detection limits, defined as the diameter of the particle which produces alpha tracks more than one for a 28-days exposure, were estimated to be 0.8, 0.9, 1.1, 2.1 and 3.0 μm for the particles having the same uranium abundance ratios with NBL CRM U850, U500, U350, U050 and U010 reference materials, respectively. The use of alpha track detection for subsequent SIMS analysis is an inexpensive and an efficient way to measure uranium-bearing particles with higher (235)U abundances. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. On the consistency among different approaches for nuclear track scanning and data processing

    Science.gov (United States)

    Inozemtsev, K. O.; Kushin, V. V.; Kodaira, S.; Shurshakov, V. A.

    2018-04-01

    The article describes various approaches for space radiation track measurement using CR-39™ detector (Tastrak). The results of comparing different methods for track scanning and data processing are presented. Basic algorithms for determination of track parameters are described. Every approach involves individual set of measured track parameters. For two sets, track scanning is sufficient in the plane of detector surface (2-D measurement), third set requires scanning in the additional projection (3-D measurement). An experimental comparison of considered techniques was made with the use of accelerated heavy ions Ar, Fe and Kr.

  18. Determination of uranium and thorium contents inside different materials using track detectors and mean critical angles

    CERN Document Server

    Misdaq, M A; Ktata, A; Merzouki, A; Youbi, N

    1999-01-01

    The critical angles of the CR-39 (theta sub c) and LR-115 type II (theta sub c ') solid state nuclear track detectors (SSNTD) for detecting alpha-particles emitted by the uranium and thorium series have been evaluated by calculating the corresponding ranges of the emitted alpha-particles in different material samples and in the SSNTD studied. The influence of the emitted alpha-particles initial and residual energies on the critical angles of the SSNTD studied has been investigated. The uranium and thorium contents of different geological samples have been evaluated by exploiting data obtained for the critical angles of the CR-39 and LR-115 type II solid state nuclear track detectors and measuring the corresponding densities of tracks.

  19. Fast neutron detection using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Vilela, E.C.

    1990-01-01

    CR-39 and Makrofol-E solid state nuclear track detectors were studied aiming their application to fast neutron detection. Optimum etching conditions of those two kinds of materials were determined the followings - the Makrofol-E detector is electrochemically etched in a PEW solution (15% KOH, 40% ethilic alcohol and 45% water) for 2 h., with an applied electric field strength of 30 kV/cm (r/m/s/) and frequency of 2 kHz, at room temperature; - the CR-39 detector is chemically pre-etched during 1 h in a 20% (w/v) NaOH solution at 70 sup(0)C, followed by 13 h electrochemical etch using the same solution at room temperature and an electric field strength of 30 kV/cm (r.m.s.) and frequency of 2 kHz.(E.G.)

  20. Characteristics of diallyl phthalate resin as a fission track detector

    CERN Document Server

    Tsuruta, T

    1999-01-01

    Diallyl phthalate (DAP) resin plates were irradiated with fission fragments, and then etched in aqueous solution of KOH. Etched tracks were observed and counted by using an optical microscope. The detection efficiency of fission fragments was about 100% for both perpendicular and random incidence. DAP plates were insensitive to alpha particles and fast neutrons. These characteristics are suitable for detecting selected fission fragments, which coexist with alpha particles or fast neutrons. DAP plates are valuable for quantitative analysis of fissionable materials and neutron dosimetry. DAP and allyl diglycol carbonate (CR-39) were formed into copolymers in various ratios. The copolymers showed intermediate characteristics between DAP and CR-39. The fabrication of the copolymers made it possible to control the discrimination level for detection of heavy charged particles.

  1. Ion track pores in intelligent films

    International Nuclear Information System (INIS)

    Asano, Masaharu; Yoshida, Masaru; Omichi, Hideki; Nagaoka, Noriyasu; Kubota, Hitoshi; Katakai, Ryoichi; Reber, N.; Spohr, R.

    1996-01-01

    To create an intelligent chemical valve which behaves to biological membranes, we combined the following technologies: (1) creation of intelligent gels based on pendant α-amino acids or their oligomers, (2) preparation of nuclear track films by etching chemically after heavy ion irradiation, especially preparation of cylindrical pores passed through the film, and (3) a combination of (1) and (2). The two factors, REL (Restricted Energy Loss) and radiation sensitivity [(V t /V b )-1] play an important role in formation of such cylindrical track films. In the case of CR-39 film, there were found to be REL>1.6x10 4 MeV cm 2 g -1 and (V t /V b )-1>100, respectively. The cylindrical tracks films with intelligent functions, which consist of a combination of (1) and (2), can be fabricated by two techniques, copolymerization and grafting. (author)

  2. Response comparative study of Rn-222 alpha particles track monitors

    International Nuclear Information System (INIS)

    Pereira, Osvaldo Luiz dos Santos

    2010-01-01

    This work was a comparative study between the responses of three monitors, the NRPB, an acrylic monitor (in thin film geometry) and the aluminum monitor (also thin film geometry) in controlled and mixed environment. The experiments consisted on placing the monitors in a plastic tube, with a radio-226 source internal. Only internal CR-39 plastic detectors were analyzed in this work. It was found that the monitors in thin film geometry had activities response of approximately 15% less than the NRPB monitors. All monitors responded the same way when in controlled environment. Related to the type of material, conductive plastic or dielectric (insulator) plastic, the NRPB, in environments without ventilation, responded in the same way. (author)

  3. Fibre tracking

    International Nuclear Information System (INIS)

    Gaillard, J.M.

    1994-03-01

    A large-size scintillating plastic fibre tracking detector was built as part of the upgrade of the UA2 central detector at the SPS proton-antiproton collider. The cylindrical fibre detector of average radius of 40 cm consisted of 60000 plastic fibres with an active length of 2.1 m. One of the main motivations was to improve the electron identification. The fibre ends were bunched to be coupled to read-out systems of image intensifier plus CCD, 32 in total. The quality and the reliability of the UA2 fibre detector performance exceeded expectations throughout its years of operation. A few examples of the use of image intensifiers and of scintillating fibres in biological instrumentation are described. (R.P.) 11 refs., 15 figs., 2 tabs

  4. TRACK--A new method for the evaluation of low-level extinction coefficient in optical films.

    Science.gov (United States)

    Vernhes, R; Martinu, L

    2015-11-02

    We develop a rigorous methodology named TRACK based on the collection of multi-angle spectrophotometric transmission and reflection data in order to assess the extinction coefficient of quasi-transparent optical films. The accuracy of extinction coefficient values obtained by this method is not affected by sample non-idealities (thickness non-uniformity, refractive index inhomogeneities, anisotropy, interfaces, etc.) and therefore a simple two-layer (substrate/film) optical model can be used. The method requires the acquisition of transmission and reflection data at two angles of incidence: 10° and 65° in p polarization. Data acquired at 10° provide information about the film thickness and the refractive index, while data collected at 65° are used for absorption evaluation and extinction coefficient computation. We test this method on three types of samples: (i) a CR-39 plastic substrate coated with a thick protective coating; (ii) the same substrate coated with a thin TiO(2) film; (iii) and a thick Si(3)N(4) film deposited on Gorilla glass that presents thickness non-uniformity and refractive index gradient non-idealities. We also compare absorption and extinction coefficient values obtained at 410 and 550 nm by both TRACK and Laser Induced Deflection techniques in the case of a 1 micron thick TiO(2) coating. Both methods display consistent extinction coefficient values in the 10(-4) and 10(-5) ranges at 410 and 550 nm, respectively, which proves the validity of the methodology and provides an estimate of its accuracy limit.

  5. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    Energy Technology Data Exchange (ETDEWEB)

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford`s mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  6. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    Energy Technology Data Exchange (ETDEWEB)

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford's mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  7. Novel polysulphonates and poly(sulphonate-co-carbonate) polymers for nuclear track detection

    Energy Technology Data Exchange (ETDEWEB)

    Mandrekar, Vinod K.; Tilve, S.G. [Department of Chemistry, Goa University, Taliegao Plateau, Goa 403 206 (India); Nadkarni, V.S. [Department of Chemistry, Goa University, Taliegao Plateau, Goa 403 206 (India)], E-mail: nitin@unigoa.ac.in

    2008-09-15

    Preparation of homopolymer from diethylene glycol bis(allyl sulphonate) (DEAS) and its several copolymers with allyl diglycol carbonate (ADC) and their preliminary evaluation as nuclear track detector is described. The monomer is synthesized by reacting diethylene glycol with allyl sulphonyl chloride in presence of pyridine as a base. Spectral characteristics of the monomer are also given for the first time. The designed polymers were successfully tested for detection of {sup 239}Pu alpha particles and {sup 252}Cf fission fragment tracks after etching with 6 N NaOH at 70 deg. C. Some of the polymers prepared showed even better sensitivity than (SR-86)(20) track detectors for track detection properties. The polymers are also compared with commercial CR-39 track detectors for its track detection properties.

  8. Novel polysulphonates and poly(sulphonate-co-carbonate) polymers for nuclear track detection

    International Nuclear Information System (INIS)

    Mandrekar, Vinod K.; Tilve, S.G.; Nadkarni, V.S.

    2008-01-01

    Preparation of homopolymer from diethylene glycol bis(allyl sulphonate) (DEAS) and its several copolymers with allyl diglycol carbonate (ADC) and their preliminary evaluation as nuclear track detector is described. The monomer is synthesized by reacting diethylene glycol with allyl sulphonyl chloride in presence of pyridine as a base. Spectral characteristics of the monomer are also given for the first time. The designed polymers were successfully tested for detection of 239 Pu alpha particles and 252 Cf fission fragment tracks after etching with 6 N NaOH at 70 deg. C. Some of the polymers prepared showed even better sensitivity than (SR-86)(20) track detectors for track detection properties. The polymers are also compared with commercial CR-39 track detectors for its track detection properties

  9. Design of the passive personal dosimeter for miners using an allyl diglycol carbonate plastic. Phase 1

    International Nuclear Information System (INIS)

    1983-12-01

    The report summarizes the results of the feasibility study on the design and development of a passive personal dosimeter incorporating an allyl diglycol carbonate plastic (CR39) detector, for use by uranium miners. Based upon the feasibility study, a passive personal dosimeter using a capacitor-type electrostatic enhancement device has been designed. Preliminary tests indicate that the prototype could be used in the mine environment to differentiate radon and thoron daughters with a detection efficiency comparable to that of a typical active device. Further study is required, however, into the possible influence in the mine environment of local variations in charged fraction, upon the calibration of this dosimeter

  10. Development of an automated informatic system, for the evaluation of damage in plastics and minerals

    International Nuclear Information System (INIS)

    Hidalgo V, V.; Lopez G, A.D.; Ledezma F, L.E.; Segovia R, A.; Balcazar, M.

    2008-01-01

    A computer system of pattern recognition to evaluate automatically the damages registered by positive ions in minerals and plastics was developed. In the case of minerals the apatite in which was achievement to recognize and to count the damages by spontaneous fission of the uranium contained in her was selected. The selected plastic was the CR39, in which was possible to obtain the distribution of the diameters of the you give you taken place by slight ions in this plastic. In both cases, the recognition of patterns you bases on Ision for Computer, using the methodology described by Gonzalez and Woods [6]. The technique consists in: Acquisition of the Image, Pre-prosecution, Segmentation, Description and Classification; the computer system you development making use of the software Matlab version 7. The Apatita you selects for their importance in the one dated geologic and the determination of the thermal history, both of importance in the oil prospecting. In the case of the CR39 their importance resides in its wide and massive use as dosimetro of neutrons, determination of environmental Radon and detection of nuclear reactions of low section. (Author)

  11. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  12. Temperature effects on interaction of positive ions with plastic detectors

    International Nuclear Information System (INIS)

    Mendoza Anaya, D.

    1992-01-01

    The range of heavy charged particles in matter is dependent mainly on two groups of parameters, one related to the particle characteristics (charge z, mass m, energy E) and the other characterized by the stopping medium (charge z, density ρ). Those two groups are enough to describe the particle energy lost, which is related to the residual range. Research on charge particles registration using solid state nuclear track detectors (SSNTD), probe that environmental parameters affect the stabilization and formation of the tracks. One of those, is the temperature detector which shows an important effect during the irradiation on the characteristics of the tracks produced. In order to study the dependence of track geometry as a function of irradiation temperature, some SSNTD (CR 39 type) were irradiated with α particles and fission fragments. Results of this work show the existence of irradiation temperature effect on the track geometry. It is observed a reduction of length and diameters, as temperature increases. For low irradiation temperatures, there is a reduction of the track geometry, as compared with environmental temperature. (Author)

  13. Tracking Training-Related Plasticity by Combining fMRI and DTI: The Right Hemisphere Ventral Stream Mediates Musical Syntax Processing.

    Science.gov (United States)

    Oechslin, Mathias S; Gschwind, Markus; James, Clara E

    2018-04-01

    As a functional homolog for left-hemispheric syntax processing in language, neuroimaging studies evidenced involvement of right prefrontal regions in musical syntax processing, of which underlying white matter connectivity remains unexplored so far. In the current experiment, we investigated the underlying pathway architecture in subjects with 3 levels of musical expertise. Employing diffusion tensor imaging tractography, departing from seeds from our previous functional magnetic resonance imaging study on music syntax processing in the same participants, we identified a pathway in the right ventral stream that connects the middle temporal lobe with the inferior frontal cortex via the extreme capsule, and corresponds to the left hemisphere ventral stream, classically attributed to syntax processing in language comprehension. Additional morphometric consistency analyses allowed dissociating tract core from more dispersed fiber portions. Musical expertise related to higher tract consistency of the right ventral stream pathway. Specifically, tract consistency in this pathway predicted the sensitivity for musical syntax violations. We conclude that enduring musical practice sculpts ventral stream architecture. Our results suggest that training-related pathway plasticity facilitates the right hemisphere ventral stream information transfer, supporting an improved sound-to-meaning mapping in music.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-15

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

  15. Ionizing radiation measurements on LDEF: A0015 Free flyer biostack experiment

    Science.gov (United States)

    Benton, E. V.; Frank, A. L.; Benton, E. R.; Csige, I.; Frigo, L. A.

    1995-01-01

    This report covers the analysis of passive radiation detectors flown as part of the A0015 Free Flyer Biostack on LDEF (Long Duration Exposure Facility). LET (linear energy transfer) spectra and track density measurements were made with CR-39 and Polycarbonate plastic nuclear track detectors. Measurements of total absorbed dose were carried out using Thermoluminescent Detectors. Thermal and resonance neutron dose equivalents were measured with LiF/CR-39 detectors. High energy neutron and proton dose equivalents were measured with fission foil/CR-39 detectors.

  16. A new technique for radon measurement based on a combination of a track-etch detector and activated charcoal

    Energy Technology Data Exchange (ETDEWEB)

    Sutej, T.; Krizman, M.; Ilic, R. (Institut Jozef Stefan, Ljubljana (Yugoslavia))

    1991-01-01

    A new technique for radon measurement in the natural environment was investigated. It is based on the use of activated charcoal and a track-etch detector. The charcoal acts as a radon collector from the air and the track-etch detector as a recorder of the alpha particles emitted by radon and its decay products. Our preliminary results show that the response of the new dosimeter to radon, using Deodorant activated charcoal (TOK, Yugoslavia) and a CR-39 track-etch detector, is 1.4 tracks cm{sup -2}/Bqm{sup -3}d, which is about eight times higher than that obtained with a standard track-etch dosimeter. (author).

  17. Quantification and differentiation of nuclear tracks in SSNTD by simulation of their diffraction pattern

    International Nuclear Information System (INIS)

    Palacios, D.; Palacios, F.; Vitoria, T.

    2001-01-01

    An alternative method to count and differentiate nuclear tracks in SSNTD is described. The method is based on the simulation and analysis of Fraunhofer diffraction pattern formed when coherent light passes through tracks of an etched detector. Transformation of the optical system was carried out by a digital procedure of Fourier Transform. Spectral analysis of the radial intensity distribution facilitated to quantify and differentiate tracks for its diameters. The formalism outlined is also applicable to elliptic tracks. Different components of the developed software (TRACKS) are shown. Results obtained by simulation and by the theoretical model gave satisfactory concordance. With the purpose of optimizing the proposed method, technical variants of optic microscopy are discussed. A model that considers the correction for track overlapping was developed and applied. Count error is small when track distribution changes in the field of view. The proposed method can differentiate genuine tracks from defects and anomalies of the detector. Analyzing the influence of illumination conditions and focus of the microscope on track counting and discrimination, the preliminary treatment of images obtained by the CCD camera was established. The proposed method allows, with low cost and operation simplicity, guaranteeing high speed in the obtaining of results, to calculate with good approximation track density in CR-39 detectors and to differentiate the energy of incident ions by track diameters with satisfactory accuracy and precision

  18. A new method for determining the uranium and thorium distribution in volcanic rock samples using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Bakhchi, A.; Ktata, A.; Koutit, A.; Lamine, J.; Ait nouh, F.; Oufni, L.

    2000-01-01

    A method based on using solid state nuclear track detectors (SSNTD) CR- 39 and LR-115 type II and calculating the probabilities for the alpha particles emitted by the uranium and thorium series to reach and be registered on these films was utilized for uranium and thorium contents determination in various geological samples. The distribution of uranium and thorium in different volcanic rocks has been investigated using the track fission method. In this work, the uranium and thorium contents have been determined in different volcanic rock samples by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD). The mean critical angles of etching of the solid state nuclear track detectors utilized have been calculated. A petrographical study of the volcanic rock thin layers studied has been conducted. The uranium and thorium distribution inside different rock thin layers has been studied. The mechanism of inclusion of the uranium and thorium nuclei inside the volcanic rock samples studied has been investigated. (author)

  19. Construction loads experienced by plastic composite ties.

    Science.gov (United States)

    2014-07-01

    Damage to plastic composite ties during handling and track installation has been reported by a number of railroads. Results from : a survey conducted to identify specific handling issues were used to develop field and laboratory tests to measure the ...

  20. Slab track

    OpenAIRE

    Golob, Tina

    2014-01-01

    The last 160 years has been mostly used conventional track with ballasted bed, sleepers and steel rail. Ensuring the high speed rail traffic, increasing railway track capacities, providing comfortable and safe ride as well as high reliability and availability railway track, has led to development of innovative systems for railway track. The so-called slab track was first built in 1972 and since then, they have developed many different slab track systems around the world. Slab track was also b...

  1. An automatic analyzer of solid state nuclear track detectors using an optic RAM as image sensor

    International Nuclear Information System (INIS)

    Staderini, E.M.; Castellano, A.

    1986-01-01

    An optic RAM is a conventional digital random access read/write dynamic memory device featuring a quartz windowed package and memory cells regularly ordered on the chip. Such a device is used as an image sensor because each cell retains data stored in it for a time depending on the intensity of the light incident on the cell itself. The authors have developed a system which uses an optic RAM to acquire and digitize images from electrochemically etched CR39 solid state nuclear track detectors (SSNTD) in the track count rate up to 5000 cm -2 . On the digital image so obtained, a microprocessor, with appropriate software, performs image analysis, filtering, tracks counting and evaluation. (orig.)

  2. Plastic Surgery

    Science.gov (United States)

    ... idea for teens? As with everything, there are right and wrong reasons to have surgery. Cosmetic surgery is unlikely to change your life. Most board-certified plastic surgeons spend a lot of time ... the right reasons. Many plastic surgery procedures are just that — ...

  3. Contribution to the study of radio toxicity of aromatic and medicinal plants using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Mortassim, A.; Misdaq, M.A.; Naaman, A

    2009-01-01

    The concentrations of uranium (238 U), thorium (232 Th), radon (222 Rn) and thoron (220 Rn) were measured in twenty aromatic and medicinal plants in f ind a new method based on using solid state nuclear track detectors type Cr-39 and Rs-115. He emerges from this study that the verbena and salvia have higher levels of uranium (radon) higher than that of other plants while the leaves of olive and saturja have concentrations of thorium (thoron) higher than other plants therefore radio toxicity of these plants is higher than that of others and may pose a radiological hazard if the masses are incorporated by consumers high. [fr

  4. Nuclear tracks in solids and gas radon measurements

    International Nuclear Information System (INIS)

    Espinosa, G.

    2007-01-01

    Full text: The Department of Energy (DOE), the Environmental Protection Agency (EPA) in USA, and the European Community, have dedicated significant budget to the Radon study, its health effects and remedial actions for controlling and achieving lower levels, in these cases, nationwide research programs have been organized. With the aim to contribute on the radon levels knowledge in our country, the Applied Dosimetry Project at the Physics Institute of the University of Mexico has developed an indoor and outdoor radon measurement methodology. In this paper a passive radon detector device based on CR-39 polycarbonate for use in radon research and routine measurements is presented. As well the methodology for the track formation, automatic reading system, calibration procedure and measurements in a different location, are shown in this work. The results had been compared with dynamic detection systems, and another methodologies and research groups in order to have a high confidence in the radon levels reported. (Author)

  5. Radon measurements by track detectors in Calabrian workplaces

    International Nuclear Information System (INIS)

    Nastro, V.; Niceforo, G.; Vuono, D.; Luca, P. de; Nastro, A.

    2006-01-01

    Indoor radon studies have been carried out in some workplaces of the South Calabria (Italy) by track detectors CR-39. This study has been undertaken for the purpose of safeguarding the public healthy: since the European population spends, in average, the most greater part of their time in confined environments(residences and offices) the risks of exposure can be elevated. This radon passive measurements are been effectuated according to the recommendations. The exposure time in the workplaces was two different cycle: three months, and six months. The obtained results indicate a radon concentration not only in an average of low level but also in the range of action level (>500 Bq/m 3 ). In this last case will be necessary to reduce the radon pollution by adequate land operation works, and a continuous monitoring is also necessary

  6. An SSNTD study of spontaneous fission fragments from the soil-gas samples of Bakreswar thermal springs

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Debasish; Ghose, Debasis; Sastri, R.C. E-mail: res@juphys.ernet.in

    2001-04-01

    During the course of investigations on the radon and stable gas migration around the hot spring zone at Bakreswar, Birbhum in India, it was noticed that CR-39 plastic detectors used for the detection of radon revealed tracks with much bigger diameters than usual for alpha particle tracks. Exposed CR-39 detectors etched adapting sequential etching technique confirmed the presence of bigger diameter tracks similar in nature to the tracks formed by spontaneous fission fragments. This paper presents the results of these observations along with the histogram plots of the track number versus track diameter that indicate an asymmetric distribution as was seen for mass distribution of spontaneous fission fragments.

  7. Thermonuclear fusion product diagnostics by nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Muehling, E.; Schumacher, U. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.)); Paretzke, H.G. (Gesellschaft fuer Strahlen- und Umweltforschung m.b.H. Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Strahlenschutz)

    1984-01-01

    The nuclear track detector materials CR-39 and PM-355 are capable of proton and alpha particle track recording and thus well suited to charged particle diagnostics in thermonuclear fusion devices. In a study to determine the respective absolute recording efficiencies and energy resolutions for protons and alpha particles in real diagnostics situations, a series of experiments with monoenergetic particles of known energies and angles of incidence were performed. Alpha particles could be quantitatively detected for angles of incidence of up to 70 deg, and their etch pit depth rather than the diameter for defined etching conditions gave satisfying information on the alpha particle energy. Contrary to other investigators, however, we found a monotonically decreasing detection probability for protons already above 3 MeV and no proton track could be developed above incident energies of 7 to 8 MeV. The proton detection depends more strongly on the angle of incidence; only tracks of protons with angles of incidence smaller than 30 deg could be made visible by etching. The proton energy could be derived from track diameter measurements better than from etch pit depths.

  8. Plastic dosimeter

    International Nuclear Information System (INIS)

    Nagai, Shiro; Matsuda, Kohji.

    1988-01-01

    The report outlines major features and applications of plastic dosimeters. Some plastic dosimeters, including the CTA and PVC types, detect the response of the plastic material itself to radiations while others, such as pigment-added plastic dosimeters, contain additives as radiation detecting material. Most of these dosimeters make use of color centers produced in the dosimeter by radiations. The PMMA dosimeter is widely used in the field of radiation sterilization of food, feed and medical apparatus. The blue cellophane dosimeter is easy to handle if calibrated appropriately. The rad-color dosimeter serves to determine whether products have been irradiated appropriately. The CTA dosimeter has better damp proofing properties than the blue cellophane type. The pigment-added plastic dosimeter consists of a resin such as nylon, CTA or PVC that contains a dye. Some other plastic dosimeters are also described briefly. Though having many advantages, these plastic dosimeter have disadvantages as well. Some of their major disadvantages, including fading as well as large dependence on dose, temperature, humidity and anviroment, are discussed. (Nogami, K.)

  9. Deposition of grids on plastic detectors

    CERN Document Server

    Birabeau, J P; Mendola, Onofrio

    1972-01-01

    In order to facilitate the locating of tracks of charged particles in cellulose-nitrate and polycarbonate (Makrofol, Lexan) foils, a method has been developed for the photo-deposition of translucent coordinate grids on these materials. The grids are resistant to the strongly caustic solutions used in developing tracks in plastic foils. (9 refs) .

  10. Production of grids in plastic detectors

    CERN Document Server

    Birabeau, J P; Brun, R; Cordaillat, A; Mendola, Onofrio

    1972-01-01

    In order to facilitate the locating of tracks of charged particles in cellulose nitrate and polycarbonate (makrofol, lexan) foils, a method has been developed for the photo-deposition of translucent coordinate grids on this materials. The grids are resistant to the strongly caustic solutions used in developing tracks in plastic foils. (9 refs) .

  11. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  12. Developmental plasticity

    Science.gov (United States)

    Lea, Amanda J; Tung, Jenny; Archie, Elizabeth A; Alberts, Susan C

    2017-01-01

    Abstract Early life experiences can have profound and persistent effects on traits expressed throughout the life course, with consequences for later life behavior, disease risk, and mortality rates. The shaping of later life traits by early life environments, known as ‘developmental plasticity’, has been well-documented in humans and non-human animals, and has consequently captured the attention of both evolutionary biologists and researchers studying human health. Importantly, the parallel significance of developmental plasticity across multiple fields presents a timely opportunity to build a comprehensive understanding of this phenomenon. We aim to facilitate this goal by highlighting key outstanding questions shared by both evolutionary and health researchers, and by identifying theory and empirical work from both research traditions that is designed to address these questions. Specifically, we focus on: (i) evolutionary explanations for developmental plasticity, (ii) the genetics of developmental plasticity and (iii) the molecular mechanisms that mediate developmental plasticity. In each section, we emphasize the conceptual gains in human health and evolutionary biology that would follow from filling current knowledge gaps using interdisciplinary approaches. We encourage researchers interested in developmental plasticity to evaluate their own work in light of research from diverse fields, with the ultimate goal of establishing a cross-disciplinary understanding of developmental plasticity. PMID:29424834

  13. Remote Sensing of Plastic Debris

    Science.gov (United States)

    Garaba, S. P.; Dierssen, H. M.

    2016-02-01

    Plastic debris is becoming a nuisance in the environment and as a result there has been a dire need to synoptically detect and quantify them in the ocean and on land. We investigate the possible utility of spectral information determined from hand held, airborne and satellite remote sensing tools in the detection and identification polymer source of plastic debris. Sampled debris will be compared to our derived spectral library of typical raw polymer sources found at sea and in household waste. Additional work will be to determine ways to estimate the abundance of plastic debris in target areas. Implications of successful remote detection, tracking and quantification of plastic debris will be towards validating field observations over large areas and at repeated time intervals both on land and at sea.

  14. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  15. Study of a plastic detector as a neutron dosimeter

    International Nuclear Information System (INIS)

    Cuauhtecatl Hernandes, V.

    1982-01-01

    Studies were carried out through nuclear reactions (n, p); (n, heavy ion), and (n,α) of the dosimetric properties of CR 39 commercial brand polymers. A system was devised for calculating the number of neutron induced nuclear reactions and geometric absolute efficiency factors. Feasibility of the utilization of CR 39 in monitoring and in personnel dosimeters is also discussed. (author)

  16. Radon Measurements in Egypt using passive etched track detectors. A Review

    International Nuclear Information System (INIS)

    Gomaa, M.A.; Hussein, A.S.; El-Arabi, A.M.

    2005-01-01

    Radon and its progeny may cause serious radiation harm to human health such as lung cancer and other types. Radon measurements based on alpha particles etched track detectors (LR-115, CR-39) are very attractive for assessment of radon exposure. This is due to their high sensitivity, low cost, easy to handle and retain a permanent record of data. Also these detectors can incorporate the effects of seasonal and diurnal fluctuation of radon activity concentrations due to physical, geological and meteorological factors. The present review is based mainly on the topic of passive etched track detectors for the measurements of radon in Egypt in the recent years. Published papers includes the measurements of radon in dwellings, working places, Cairo Metro stations, ancient Pharaonic places and uranium exploration galleries as well as assessment of radon in drinking water

  17. Magical Engineering Plastic

    International Nuclear Information System (INIS)

    Kim, Gwang Ung

    1988-01-01

    This book introduces engineering plastic about advantage of engineering plastic, plastic material from processing method, plastic shock, plastic until now, background of making of engineering plastic, wonderful engineering plastic science such as a high molecule and molecule, classification of high molecule, difference between metal and high molecule, heat and high molecule materials, and property of surface, engineering plastic of dream like from linseed oil to aramid, small dictionary of engineering plastic.

  18. Mixed plastics recycling technology

    CERN Document Server

    Hegberg, Bruce

    1995-01-01

    Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

  19. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  20. Plastic zonnecellen

    NARCIS (Netherlands)

    Roggen, Marjolein

    1998-01-01

    De zonnecel van de toekomst is in de maak. Onderzoekers van uiteenlopend pluimage werken eendrachtig aan een plastic zonnecel. De basis is technisch gelegd met een optimale, door invallend licht veroorzaakte, vorming van ladingdragers binnen een composiet van polymeren en buckyballs. Nu is het zaak

  1. Nuclear Track Detector Characterization via Alpha-Spectrometry for Radioprotection Use

    Energy Technology Data Exchange (ETDEWEB)

    Morelli, D.; Imme, G.; Catalano, R. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, via S. Sofia, 64- 95123 Catania (Italy); Istituto Nazionale di Fisica Nucleare - Sezione di Catania, via S. Sofia, 64- 95123 Catania (Italy); Aranzulla, M. [Istituto Nazionale Geofisica e Vulcanologia - Sezione di Catania, piazza Roma, 2- 95127 Catania (Italy); Tazzer, A. L. Rosselli; Mangano, G. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, via S. Sofia, 64- 95123 Catania (Italy)

    2011-12-13

    Solid Nuclear Track Detectors (SNTDs), CR-39 type, are usually adopted to monitor radon gas concentrations. In order to characterize the detectors according to track geometrical parameters, detectors were irradiated inside a vacuum chamber by alpha particles at twelve energy values, obtained by different Mylar foils in front of a {sup 241}Am source. The alpha energy values were verified using a Si detector. After the exposure to the alpha particles, the detectors were chemically etched to enlarge the tracks, which were then analyzed by means of a semiautomatic system composed of an optical microscope equipped with a CCD camera connected to a personal computer to store images. A suitable routine analyzed the track parameters: major and minor axis length and mean grey level, allowing us to differentiate tracks according to the incident alpha energy and then to individuate the discrimination factors for radon alpha tracks. The combined use of geometrical and optical parameters allows one to overcome the ambiguity in the alpha energy determination due to the non-monotonicity of each parameter versus energy. After track parameter determination, a calibration procedure was performed by means of a radon chamber. The calibration was verified through an inter-comparing survey.

  2. Particle tracking

    CERN Document Server

    Safarík, K; Newby, J; Sørensen, P

    2002-01-01

    In this lecture we will present a short historical overview of different tracking detectors. Then we will describe currently used gaseous and silicon detectors and their performance. In the second part we will discuss how to estimate tracking precision, how to design a tracker and how the track finding works. After a short description of the LHC the main attention is drawn to the ALICE experiment since it is dedicated to study new states in hadronic matter at the LHC. The ALICE tracking procedure is discussed in detail. A comparison to the tracking in ATLAS, CMS and LHCb is given. (5 refs).

  3. Development of an automated informatic system, for the evaluation of damage in plastics and minerals; Desarrollo de un sistema informatico automatizado, para la evaluacion de danos en plasticos y minerales

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo V, V.; Lopez G, A.D.; Ledezma F, L.E.; Segovia R, A.; Balcazar, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2008-07-01

    A computer system of pattern recognition to evaluate automatically the damages registered by positive ions in minerals and plastics was developed. In the case of minerals the apatite in which was achievement to recognize and to count the damages by spontaneous fission of the uranium contained in her was selected. The selected plastic was the CR39, in which was possible to obtain the distribution of the diameters of the you give you taken place by slight ions in this plastic. In both cases, the recognition of patterns you bases on Ision for Computer, using the methodology described by Gonzalez and Woods [6]. The technique consists in: Acquisition of the Image, Pre-prosecution, Segmentation, Description and Classification; the computer system you development making use of the software Matlab version 7. The Apatita you selects for their importance in the one dated geologic and the determination of the thermal history, both of importance in the oil prospecting. In the case of the CR39 their importance resides in its wide and massive use as dosimetro of neutrons, determination of environmental Radon and detection of nuclear reactions of low section. (Author)

  4. Plastic bronchitis

    Directory of Open Access Journals (Sweden)

    Anil Kumar Singhi

    2015-01-01

    Full Text Available Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics. They are ominous with poor prognosis. Sometimes, infection or airway reactivity may provoke cast bronchitis as a two-step insult on a vulnerable vascular bed. In such instances, aggressive management leads to longer survival. This report of cast bronchitis discusses its current understanding.

  5. Timber tracking

    DEFF Research Database (Denmark)

    Düdder, Boris; Ross, Omry

    2017-01-01

    Managing and verifying forest products in a value chain is often reliant on easily manipulated document or digital tracking methods - Chain of Custody Systems. We aim to create a new means of tracking timber by developing a tamper proof digital system based on Blockchain technology. Blockchain...

  6. Measurement of indoor radon levels in Erbil capital by using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Mansour, H.H.; Khdar, S. per; Abdulla, H.Y.; Muhamad, N.Q.; Othman, M.M.; Qader, S.

    2005-01-01

    Radon alpha activity concentration has been measured in 28 homes in the Erbil Capital-Iraqi Kurdistan region during the autumn season by using time-integrated passive radon dosimeters containing CR-39 solid state nuclear track detectors 'SSNTDs'. The radon activity concentrations in these homes range from (10.33-90.34) Bqm -3 with an average of 44+/-23Bqm -3 . The average absorption effective dose equivalent for a person living in homes for which the investigation were done was found to be 1.3+/-0.65mSvy -1 , obtained by using an equilibrium factor of 0.5 and an occupancy factor of 0.8. The average lung cancer cases per year per 10 6 person was found to be 23+/-12

  7. Neutron angular distribution in a plasma focus obtained using nuclear track detectors.

    Science.gov (United States)

    Castillo-Mejía, F; Herrera, J J E; Rangel, J; Golzarri, J I; Espinosa, G

    2002-01-01

    The dense plasma focus (DPF) is a coaxial plasma gun in which a high-density, high-temperature plasma is obtained in a focused column for a few nanoseconds. When the filling gas is deuterium, neutrons can be obtained from fusion reactions. These are partially due to a beam of deuterons which are accelerated against the background hot plasma by large electric fields originating from plasma instabilities. Due to a beam-target effect, the angular distribution of the neutron emission is anisotropic, peaked in the forward direction along the axis of the gun. The purpose of this work is to illustrate the use of CR-39 nuclear track detectors as a diagnostic tool in the determination of the time-integrated neutron angular distribution. For the case studied in this work, neutron emission is found to have a 70% contribution from isotropic radiation and a 30% contribution from anisotropic radiation.

  8. Utilization of plastic detectors in autoradiographic studies of radioactive minerals from the Lagoa Real uranium Province, state of Bahia, Brazil

    International Nuclear Information System (INIS)

    Brandao, P.M.C.

    1984-01-01

    A short account on an autoradiographic technique using plastic detectors, it's methodology, application and results is presented. With this technique the distribution of radioactive minerals in rocks can be studied in detail. As radioactive source for this study, samples mineralized in uraninite and/or pitchblende were used. The utilized detectors were the CR-39 (a polymer plate) and films of celulose nitrate: CA-80-15 and CN-85. The mineralization is associated to mafics (amphibole, pyroxene, biotite, garnet, etc.) and to plagioclase (albite or albite-oligoclase), occurring as small inclusions and also in microfractures, cleavages and grain boundaries, mainly among plagioclase crystals which occur close to or practically touching mafic minerals. (Author) [pt

  9. Overcoming maladaptive plasticity through plastic compensation

    Directory of Open Access Journals (Sweden)

    Matthew R.J. MORRIS, Sean M. ROGERS

    2013-08-01

    Full Text Available Most species evolve within fluctuating environments, and have developed adaptations to meet the challenges posed by environmental heterogeneity. One such adaptation is phenotypic plasticity, or the ability of a single genotype to produce multiple environmentally-induced phenotypes. Yet, not all plasticity is adaptive. Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution, much less is known about maladaptive plasticity. However, maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments. This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity, two of which involve genetic changes (standing genetic variation, genetic compensation and two of which do not (standing epigenetic variation, plastic compensation. Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity. In particular, plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence. We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change [Current Zoology 59 (4: 526–536, 2013].

  10. Development of a CCD based system called DIGITRACK for automatic track counting and evaluation

    International Nuclear Information System (INIS)

    Molnar, J.; Somogyi, G.; Szilagyi, S.; Sepsy, K.

    1984-01-01

    We have developed, to the best of our knowledge, the first automatic track analysis system (DIGITRACK) in which the video signals are processed by a new type of video-receiver called charge-coupled device (CCD). The photosensitive semi-conductor device is a 2.5 cm long line imager of type Fairchild CCD 121HC which converts one row of the picture seen through a low magnification microscope into 1728 binary signals by a thresholding logic. The picture elements are analysed by a microcomputer equipped with two INTEL 8080 microprocessors and interfaced to a PDP-11/40 computer. The microcomputer also controls the motion of the stage of microscope. For pattern recognition and analysis a software procedure is developed which is able to differentiate between overlapping tracks and to determine the number, surface opening and x-y coordinates of the tracks occurring in a given detector area. The distribution of track densities and spot areas on the detector surface can be visualized on a graphic display. The DIGITRACK system has been tested for analysis of alpha-tracks registered in CR-39 and LR-115 detectors. (author)

  11. A novel room temperature-induced chemical etching (RTCE) technique for the enlargement of fission tracks in Lexan polycarbonate SSNTD

    International Nuclear Information System (INIS)

    Chavan, Vivek; Kalsi, P.C.; Manchanda, V.K.

    2011-01-01

    The chemical or electrochemical etching is an essential step to enlarge the ion-induced latent tracks in solid state nuclear track detectors (SSNTDs). In these methods, above ambient temperatures (∼60 o C) and moderately high concentrations of alkali are required for about 1-2 h to enlarge the latent tracks. Microwave induced chemical etching method is reported to reduce the etching time for alpha tracks from 3 to 4 h to 25 min for CR-39 detector. In the present work, a room temperature-induced chemical etching employing ethanolamine as a new etchant has been investigated for the first time to enlarge the fission tracks in Lexan polycarbonate SSNTD. The tracks developed in the Lexan detectors etched at room temperature using ethanolamine are compared with those etched with routinely used chemical etching (CE) technique in 6 N NaOH at 60 o C. The bulk etch and track etch rates are also reported. The detection efficiency of RTCE method is determined and compared with that of CE method. The RTCE technique is found to be simple, fast and convenient.

  12. Neutron response study using PADC

    International Nuclear Information System (INIS)

    El-Badry, B.A; Hegazy, T.M; Morsy, A.A.; Zaki, M.F.

    2007-01-01

    The results of an experimental work aimed at improving the performances of the Cr-39 nuclear track detector for neutron dosimetry applications. So, a set of Cr-39 plastic detectors was exposed to 252 Cf neutron source, which has the emission rate of 0.68 x 10 8 s ( -1), and neutron dose equivalent rate 1m apart from the source is equal to 3.8 mrem/h. The detection of fast neutrons performed with Cr-39 detector foils, subsequent chemical etching and evaluation of the etched tracks by an automatic track counting system was studied. It is found that the track density grows with the increase of neutron dose and etching time. These results. are compared with previous work. It is found that there is a matching and good agreement with their investigations

  13. Antireflection coatings on plastics deposited by plasma ...

    Indian Academy of Sciences (India)

    Wintec

    advantageous material for spectacle lenses. CR39 is also resistant to most solvents and other chemicals, to gamma radiation, to aging and to material fatigue. Polycarbonate (PC), specifically polycarbonate of bisphenol-A, is an example of a thermoplastic material— it softens when heated, hardens when cooled, and PC.

  14. Providing plastic zone extrusion

    Science.gov (United States)

    Manchiraju, Venkata Kiran; Feng, Zhili; David, Stan A.; Yu, Zhenzhen

    2017-04-11

    Plastic zone extrusion may be provided. First, a compressor may generate frictional heat in stock to place the stock in a plastic zone of the stock. Then, a conveyer may receive the stock in its plastic zone from the compressor and transport the stock in its plastic zone from the compressor. Next, a die may receive the stock in its plastic zone from the conveyer and extrude the stock to form a wire.

  15. Predictors of readmission after outpatient plastic surgery.

    Science.gov (United States)

    Mioton, Lauren M; Buck, Donald W; Rambachan, Aksharananda; Ver Halen, Jon; Dumanian, Gregory A; Kim, John Y S

    2014-01-01

    Hospital readmissions have become a topic of focus for quality care measures and cost-reduction efforts. However, no comparative multi-institutional data on plastic surgery outpatient readmission rates currently exist. The authors endeavored to investigate hospital readmission rates and predictors of readmission following outpatient plastic surgery. The 2011 National Surgical Quality Improvement Program database was reviewed for all outpatient procedures. Unplanned readmission rates were calculated for all 10 tracked surgical specialties (i.e., general, thoracic, vascular, cardiac, orthopedics, otolaryngology, plastics, gynecology, urology, and neurosurgery). Multivariate logistic regression models were used to determine predictors of readmission for plastic surgery. A total of 7005 outpatient plastic surgery procedures were isolated. Outpatient plastic surgery had a low associated readmission rate (1.94 percent) compared with other specialties. Seventy-five patients were readmitted with a complication. Multivariate regression analysis revealed obesity (body mass index ≥ 30), wound infection within 30 days of the index surgery, and American Society of Anesthesiologists class 3 or 4 physical status as significant predictors for unplanned readmission. Unplanned readmission after outpatient plastic surgery is infrequent and compares favorably to rates of readmission among other specialties. Obesity, wound infection within 30 days of the index operation, and American Society of Anesthesiologists class 3 or 4 physical status are independent predictors of readmission. As procedures continue to transition into outpatient settings and the drive to improve patient care persists, these findings will serve to optimize outpatient surgery use.

  16. Tracking Information

    NARCIS (Netherlands)

    van Benthem, J.; Bimbó, K.

    2016-01-01

    Depending on a relevant task at hand, information can be represented at different levels, less or more detailed, each supporting its own appropriate logical languages. We discuss a few of these levels and their connections, and investigate when and how information growth at one level can be tracked

  17. Fragmentation of Pb-Projectiles at SPS Energies

    CERN Multimedia

    2002-01-01

    % EMU17 \\\\ \\\\ We have exposed stacks consisting of solid state nuclear track detectors (CR-39 plastic and BP-1 glass) and different target materials at the SPS to beams of Pb projectiles. Our detectors record tracks of relativistic nuclei with charge numbers of Z~$\\geq$~6 for CR-39 and Z~$\\geq$75 for BP-1. After development of the tracks by etching they are detected and measured using completely automated microscope systems. Thus experiments with high statistics are possible. \\\\ \\\\BP-1 detectors were exposed to measure total charge changing cross sections and elemental production cross sections for heavy projectile fragments. These experiments were performed for different targets CH$ _{2} $, C, Al, Cu, Ag and Pb. Comparison of the results for different targets allows to investigate contributions to charge changing reactions by electromagnetic dissociation. Multifragmentation events in which several intermediate mass fragments are emitted from the heavy Pb projectile are studied using stacks containing CR-39 d...

  18. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like......, for example, gutters, window frames, car parts and transportation boxes have long lifetimes and thus appear as waste only many years after they have been introduced on the market. Plastic is constantly being used for new products because of its attractive material properties: relatively cheap, easy to form......, good strength and long durability. Recycling of plastic waste from production is well-established, while recycling of postconsumer plastic waste still is in its infancy. This chapter describes briefly how plastic is produced and how waste plastic is recycled in the industry. Quality requirements...

  19. Track detection methods of radium measurements

    International Nuclear Information System (INIS)

    Somogyi, G.

    1986-06-01

    The principles of tack formation and processing including the description of etching and etch-track evaluation for the preferably used plastic track detectors are discussed. Measuring methods to determine 226 Ra activity based either on the mapping of alpha-decaying elements in the complete U-Ra series by alpha-radiography, or on the measurement of uranium alone by neutron induced fissionography, or on the alpha-decay measurement of 222 Rn, the first daughter element of radium, and finally on the measurement of alpha-tracks originating from radium itself, which is separated from its parent nuclides are described in detail. (V.N.)

  20. Tracking Porters

    DEFF Research Database (Denmark)

    Bruun, Maja Hojer; Krause-Jensen, Jakob; Saltofte, Margit

    2015-01-01

    Anthropology attempts to gain insight into people's experiential life-worlds through long-term fieldwork. The quality of anthropological knowledge production, however, does not depend solely on the duration of the stay in the field, but also on a particular way of seeing social situations. The an...... the students followed the work of a group of porters. Drawing on anthropological concepts and research strategies the students gained crucial insights about the potential effects of using tracking technologies in the hospital....

  1. Plasticity and Geotechnics

    Science.gov (United States)

    Yu, Hai-Sui

    Plasticity and Geotechnics is the first attempt to summarize and present, in one volume, the major developments achieved to date in the field of plasticity theory for geotechnical materials and its applications to geotechnical analysis and design.

  2. Wood-plastic combination

    International Nuclear Information System (INIS)

    Schaudy, R.

    1978-02-01

    A review on wood-plastic combinations is given including the production (wood and plastic component, radiation hardening, curing), the obtained properties, present applications and prospects for the future of these materials. (author)

  3. Weinig plastic in vissenmaag

    NARCIS (Netherlands)

    Foekema, E.M.

    2012-01-01

    Waar de magen van sommige zeevogels vol plastic zitten, lijken vissen in de Noordzee nauwelijks last te hebben van kunststofafval. Onderzoekers die plastic resten zochten in vissenmagen vonden ze in elk geval nauwelijks.

  4. Plastic casting resin poisoning

    Science.gov (United States)

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  5. Exposure of Plastic Track Detectors to Relativistic Pb Beam for the Purpose of Providing Calibration for the DUBLIN-ESTEC Ultra Heavy Cosmic Ray Experiment Which was Exposed for Sixty-Nine Months in Earth Orbit

    CERN Multimedia

    2002-01-01

    % WA100 \\\\ \\\\ Solid state nuclear track detectors which formed part of the Dublin-ESTEC ultra heavy~cosmic~ray experiment aboard LDEF (Long Duration Exposure Facility) and which was deployed in Earth orbit for sixty-nine months, will be exposed to relativistic Pb ions. The experiment was the largest of its kind ever undertaken in space and has successfully accumulated more than fifteen times the world sample of cosmic ray nuclei in the region above Z~=~70. The data include the first significant sample of cosmic ray actinide elements and is of major astrophysical importance. The total number of ultra heavy nuclei (Z~$>$~70) in the Dublin-ESTEC sample is $\\sim$~2800. \\\\ \\\\The exposure will be very simple. A stack of detectors (20.5~cm~x~26~cm x~3~cm in size) will be irradiated with a low density beam of Pb ions (a few hundred per cm$^2$ would be ideal, but a wide range of densities and areas could be tolerated). The response of the detectors to these ions of known charge and velocity will be measured and the da...

  6. Chemical Recycle of Plastics

    OpenAIRE

    Sara Fatima

    2014-01-01

    Various chemical processes currently prevalent in the chemical industry for plastics recycling have been discussed. Possible future scenarios in chemical recycling have also been discussed. Also analyzed are the effects on the environment, the risks, costs and benefits of PVC recycling. Also listed are the various types of plastics and which plastics are safe to use and which not after rcycle

  7. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The Objective for 2006 was to complete all of the CMS Tracker sub-detectors and to start the integration of the sub-detectors into the Tracker Support Tube (TST). The Objective for 2007 is to deliver to CMS a completed, installed, commissioned and calibrated Tracking System (Silicon Strip and Pixels) aligned to < 100µ in April 2008 ready for the first physics collisions at LHC. In November 2006 all of the sub-detectors had been delivered to the Tracker Integration facility (TIF) at CERN and the tests and QA procedures to be carried out on each sub-detector before integration had been established. In December 2006, TIB/TID+ was integrated into TOB+, TIB/TID- was being prepared for integration, and TEC+ was undergoing tests at the final tracker operating temperature (-100 C) in the Lyon cold room. In February 2007, TIB/TID- has been integrated into TOB-, and the installation of the pixel support tube and the services for TI...

  8. Plastic value chains

    DEFF Research Database (Denmark)

    Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

    2014-01-01

    Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example......, plastics from WEEE is chosen as a Nordic case study. The project aims to propose a number of improvements for this value chain together with representatives from Nordic stakeholders. Based on the experiences made, a guide for other plastic value chains shall be developed....

  9. Glassy metallic plastics

    Science.gov (United States)

    Li, Jianfu; Wang, Junqiang; Liu, Xiaofeng; Zhao, Kun; Zhang, Bo; Bai, Haiyang; Pan, Mingxiang; Wang, Weihua

    2010-03-01

    This paper reports a class of bulk metallic glass including Ce-, LaCe-, CaLi-, Yb-, and Sr-based metallic glasses, which are regarded as glassy metallic plastics because they combine some unique properties of both plastics and metallic alloys. These glassy metallic plastics have very low glass transition temperature ( T g ˜25°C to 150°C) and low Young’s modulus (˜20 GPa to 35 GPa). Similar to glassy plastics, these metallic plastics show excellent plastic-like deformability on macro-, micro- and even nano-scale in their supercooled liquid range and can be processed, such as elongated, compressed, bent, and imprinted at low temperatures, in hot water for instance. Under ambient conditions, they display such metallic properties as high thermal and electric conductivities and excellent mechanical properties and other unique properties. The metallic plastics have potential applications and are also a model system for studying issues in glass physics.

  10. Determination of boron distribution in rat's brain, kidney and liver.

    Science.gov (United States)

    Pazirandeh, Ali; Jameie, Behnam; Zargar, Maysam

    2009-07-01

    To determine relative boron distribution in rat's brain, liver and kidney, a mixture of boric acid and borax, was used. After transcardial injection of the solution, the animals were sacrificed and the brain, kidney and liver were removed. The coronal sections of certain areas of the brain were prepared by freezing microtome. The slices were sandwiched within two pieces of CR-39. The samples were bombarded in a thermal neutron field of the TRR pneumatic facility. The alpha tracks are registered on CR-39 after being etched in NaOH. The boron distribution was determined by counting these alpha tracks CR-39 plastics. The distribution showed non-uniformity in brain, liver and kidney.

  11. Study of the influence of the soil and plant natures and pollution on the radon and thoron alpha activities inside various herbal infusions by using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Ait nouh, F.; Bourzik, W.; Lamine, J.

    2000-01-01

    Different medicinal plant, spinach and cereal samples have been analysed by using neutron activation analysis and radiochemical separation. The solid state nuclear track detectors technique was utilized for uranium and thorium contents determination as well as for alpha, beta, and gamma dose rates evaluation in various geological and ceramic samples. In this study, uranium and thorium contents have been determined in different plant samples, soils in which they have been grown and in herbal infusions made by boiling the studied plants in potable water by using CR-39 and LR-115 solid state nuclear track detectors. Radon and thoron alpha activities per unit volume inside the plants, soils and herbal infusions studied have been evaluated. The radon transfers between soils and plants as well as between plants and herbal infusions have been investigated. The influence of pollution due to different material dusts on radon and thoron alpha activities inside the plants and their corresponding infusions has been studied. (author)

  12. Our plastic age

    Science.gov (United States)

    Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste plastic, the effects of plastic debris on wildlife and concerns for human health that arise from the production, usage and disposal of plastics. Finally, we consider some possible solutions to these problems together with the research and policy priorities necessary for their implementation. PMID:19528049

  13. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve...

  14. Our plastic age

    OpenAIRE

    Thompson, Richard C.; Swan, Shanna H.; Moore, Charles J.; vom Saal, Frederick S.

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production. In this Theme Issue of Philosophical Transactions of the Royal Society, we describe current and future trends in usage, together with the many benefits that plastics bring to society. At the same time, we examine the environmental consequences resulting from the accumulation of waste pl...

  15. Plastic surgery pitfalls.

    Science.gov (United States)

    Gorney, M

    1999-01-01

    As a founding member of the physician-owned insurance carrier The Doctors' Company, the author has reviewed many plastic surgery policy claims. In this article, he presents an overview of the plastic surgery procedures that produce the most severe losses. He then offers suggestions on how to proceed with these "medical malpractice favorites." The author discusses potential antitrust traps and legal recourse for plastic surgeons.

  16. Challenges in plastics recycling

    OpenAIRE

    Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann; Damgaard, Anders; Astrup, Thomas Fruergaard

    2015-01-01

    Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study was undertaken to investigate the factors affecting quality in plastics recycling. The preliminary results showed factors primarily influencing quality of plastics recycling to be polymer cross contamin...

  17. Plasticized phenolphthalein polycarbonate

    Science.gov (United States)

    Harrison, E. S.

    1976-01-01

    Phenolphthalein polycarbonate was successfully plasticized with polychlorinated biphenyls (e.g., Aroclor 1231) or tricresyl phosphate and cast from tetrahydrofuran to give clear films without loss of fire resistance. At loadings of 20 to 30 percent plasticizer the Tg was lowered to approximately 100 C which would render phenolphthalein polycarbonate easily moldable. Although these materials had some mechanical integrity as shown by their film forming ability, the room temperature toughness of the plasticized polymer was not significantly improved over unmodified polymer.

  18. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The successful commissioning of ~ 25% of the Silicon Strip Tracker was completed in the Tracker Integration Facility (TIF) at CERN on 18 July 2007 and the Tracker has since been prepared for moving and installation into CMS at P5. The Tracker will be ready to move on schedule in September 2007. The Installation of the Tracker cooling pipes and LV cables between Patch Panel 1 (PP1) on the inside the CMS magnet cryostat, and the cooling plants and power system racks on the balconies has been completed. The optical fibres from PP1 to the readout FEDs in the USC will be installed in parallel with the installation of the EB/HB services, and will be completed in October. It is planned to install the Tracker into CMS at the end of October, after the completion of the installation of the EB/HB services. The Tracker will then be connected to the pre-installed services on YB0 and commissioned with CMS in December. The FPix and BPix continue to make ...

  19. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The successful commissioning of ~ 25% of the Silicon Strip Tracker was completed in the Tracker Integration Facility (TIF) at CERN in July 2007 and the Tracker has since been prepared for moving and installation into CMS at P5. The Tracker was ready to move on schedule in September 2007. The Installation of the Tracker cooling pipes and LV cables between Patch Panel 1 (PP1) on the inside the CMS magnet cryostat, and the cooling plants and power system racks on the balconies has been completed. The optical fibres from PP1 to the readout FEDs in the USC have been installed, together with the Tracker cable channels, in parallel with the installation of the EB/HB services. All of the Tracker Safety, Power, DCS and the VME Readout Systems have been installed at P5 and are being tested and commissioned with CMS. It is planned to install the Tracker into CMS before Christmas. The Tracker will then be connected to the pre-installed services on Y...

  20. Plasticity: modeling & computation

    National Research Council Canada - National Science Library

    Borja, Ronaldo Israel

    2013-01-01

    .... "Plasticity Modeling & Computation" is a textbook written specifically for students who want to learn the theoretical, mathematical, and computational aspects of inelastic deformation in solids...

  1. What Is Neural Plasticity?

    Science.gov (United States)

    von Bernhardi, Rommy; Bernhardi, Laura Eugenín-von; Eugenín, Jaime

    2017-01-01

    "Neural plasticity" refers to the capacity of the nervous system to modify itself, functionally and structurally, in response to experience and injury. As the various chapters in this volume show, plasticity is a key component of neural development and normal functioning of the nervous system, as well as a response to the changing environment, aging, or pathological insult. This chapter discusses how plasticity is necessary not only for neural networks to acquire new functional properties, but also for them to remain robust and stable. The article also reviews the seminal proposals developed over the years that have driven experiments and strongly influenced concepts of neural plasticity.

  2. Additives in plastics.

    Science.gov (United States)

    Deanin, R D

    1975-01-01

    The polymers used in plastics are generally harmless. However, they are rarely used in pure form. In almost all commercial plastics, they are "compounded" with monomeric ingredients to improve their processing and end-use performance. In order of total volume used, these monomeric additives may be classified as follows: reinforcing fibers, fillers, and coupling agents; plasticizers; colorants; stabilizers (halogen stabilizers, antioxidants, ultraviolet absorbers, and biological preservatives); processing aids (lubricants, others, and flow controls); flame retardants, peroxides; and antistats. Some information is already available, and much more is needed, on potential toxicity and safe handling of these additives during processing and manufacture of plastics products. PMID:1175566

  3. Semantic Audio Track Mixer

    OpenAIRE

    Uhle, C.; Herre, J.; Ridderbusch, F.; Popp, H.

    2011-01-01

    An audio mixer for mixing a plurality of audio tracks to a mixture signal comprises a semantic command interpreter (30; 35) for receiving a semantic mixing command and for deriving a plurality of mixing parameters for the plurality of audio tracks from the semantic mixing command; an audio track processor (70; 75) for processing the plurality of audio tracks in accordance with the plurality of mixing parameters; and an audio track combiner (76) for combining the plurality of audio tracks proc...

  4. Proton beam dosimetry: a comparison between a plastic scintillator, ionization chamber and faraday cup

    International Nuclear Information System (INIS)

    Ghergherehchi, Mitra; Afarideh, Hossein; Mohammadzadeh, Ahmad; Boghrati, Behzad; Ghannadi, Mohammad; Aslani, Golam Reza

    2010-01-01

    In this study, a comparison was made between a plastic scintillator (BC400), a Faraday Cup (FC) and an ionization chamber (IC) used for routine proton dosimetry. Thin scintillators can be applied to proton dosimetry and consequently to proton therapy as relative dosimeters because of their water-equivalent nature, high energy-light conversion efficiency, low dimensions and good proportionality to the absorbed dose at low stopping powers. To employ such scintillators as relative dosimeters in proton therapy, the corrective factors must be applied to correct the quenching luminescence at the Bragg peak. A fine linear proportionality between the luminescence light yield Y and the proton flux in a thin (0.5 mm) scintillator for the 20 and 30 MeV proton beams were observed. The experimental peak/plateau ratios of Bragg Curve for 2, 1 and 0.5 mm scintillators with an accuracy of 0.5% were obtained to be 1.87, 1.91 and 2.30, respectively. With combination of the Markus chamber and the CR-39 detector, the peak/plateau ratio was improved to 3.26. The obtained data of the luminescence yield as a function of the specific energy loss is in agreement with the Craun-Birk's theory. Results show that the FC and Markus ionization chamber are in agreement within 4%, while the FC gives a lower dose evaluation. For a defined beam, the data for the fluence measurements are reproducible within a good accuracy. (author)

  5. Proton beam dosimetry: a comparison between a plastic scintillator, ionization chamber and Faraday cup.

    Science.gov (United States)

    Ghergherehchi, Mitra; Afarideh, Hossein; Ghannadi, Mohammad; Mohammadzadeh, Ahmad; Aslani, Golam Reza; Boghrati, Behzad

    2010-01-01

    In this study, a comparison was made between a plastic scintillator (BC400), a Faraday Cup (FC) and an ionization chamber (IC) used for routine proton dosimetry. Thin scintillators can be applied to proton dosimetry and consequently to proton therapy as relative dosimeters because of their water-equivalent nature, high energy-light conversion efficiency, low dimensions and good proportionality to the absorbed dose at low stopping powers. To employ such scintillators as relative dosimeters in proton therapy, the corrective factors must be applied to correct the quenching luminescence at the Bragg peak. A fine linear proportionality between the luminescence light yield Y and the proton flux in a thin (0.5 mm) scintillator for the 20 and 30 MeV proton beams were observed. The experimental peak/plateau ratios of Bragg Curve for 2, 1 and 0.5 mm scintillators with an accuracy of 0.5% were obtained to be 1.87, 1.91 and 2.30, respectively. With combination of the Markus chamber and the CR-39 detector, the peak/plateau ratio was improved to 3.26. The obtained data of the luminescence yield as a function of the specific energy loss is in agreement with the Craun-Birk's theory. Results show that the FC and Markus ionization chamber are in agreement within 4%, while the FC gives a lower dose evaluation. For a defined beam, the data for the fluence measurements are reproducible within a good accuracy.

  6. Plastic Surgery: Tackling Misconceptions

    African Journals Online (AJOL)

    Misconceptions. Dear Sir,. Denadai and Raposo-Amaral have presented an interesting account of undergraduate plastic surgery education and the challenges associated with it.[1] They have outlined a comprehensive program to ensure that medical students get a much deeper understanding of the activities of plastic ...

  7. Plastic soep en Stormvogels

    NARCIS (Netherlands)

    Franeker, van J.A.; Offereins, M.; Domis, M.

    2017-01-01

    Plastic soep is een van de grootste problemen in het oppervlaktewater. Dat verschijnsel is niet nieuw; in 1997 werd al melding gemaakt van grote hoeveelheden plastic afval in het zeewater. Voor een langlopend onderzoek
    naar de trends in de kwaliteit van het zeewater wordt gebruikgemaakt van de

  8. Genetic architecture and phenotypic plasticity of thermally-regulated traits in an eruptive species, Dendroctonus ponderosae

    Science.gov (United States)

    Barbara J. Bentz; Ryan B. Bracewell; Karen E. Mock; Michael E. Pfrender

    2011-01-01

    Phenotypic plasticity in thermally-regulated traits enables close tracking of changing environmental conditions, and can thereby enhance the potential for rapid population increase, a hallmark of outbreak insect species. In a changing climate, exposure to conditions that exceed the capacity of existing phenotypic plasticity may occur. Combining information on genetic...

  9. DESIGNERS’ KNOWLEDGE IN PLASTICS

    DEFF Research Database (Denmark)

    Eriksen, Kaare

    2013-01-01

    The Industrial designers’ knowledge in plastics materials and manufacturing principles of polymer products is very important for the innovative strength of the industry, according to a group of Danish plastics manufacturers, design students and practicing industrial designers. These three groups...... that the designers’ lack of knowledge concerning polymer materials and manufacturing methods can be problematic or annoying, and design students from most Danish design universities express the need for more contact with the industry and more competencies and tools to handle even simple topics when designing plastic...... answered the first Danish national survey, PD13[1], investigating the importance of industrial designers’ knowledge in plastics and the collaboration between designers and the polymer industry. The plastics industry and the industrial designers collaborate well, but both groups frequently experience...

  10. Examining the fragmentation of 158 A GeV lead ions on copper target: Charge-changing cross sections

    International Nuclear Information System (INIS)

    Rana, Mukhtar Ahmed; Manzoor, Shahid

    2008-01-01

    A stack of plastic CR-39 Track Detectors were exposed to 158 A GeV 207 Pb ions at the CERN-SPS beam facility. The exposure of stack was performed at normal incidence with a fluence of about 1500ions/cm 2 . The total number of lead ions in each spill was about 7.8x10 4 with eight spills on each stack. For the stack with the Cu target, the lengths of etched cones on one face of the CR-39 detectors (before and after the target) were measured. Using these measurements and charge identification methodology in CR-39 track detectors, total and partial charge changing cross sections of 158 A GeV Pb 82+ ions on Cu and CR-39 targets are determined in the charge region 63≤Z≤82. The possibilities of presence and absence of odd-even effect in measured partial charge changing cross sections of 158 A GeV Pb ions for Cu and CR-39 targets are described. The charge resolution (σ Z ) achieved in the present experiment is ∼0.18e-0.21e. The analysis of discrepancies between our experimental results and other published results for the identical reaction is also presented

  11. Examining the fragmentation of 158 A GeV lead ions on copper target: Charge-changing cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Mukhtar Ahmed [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)], E-mail: marana@alumni.nus.edu.sg; Manzoor, Shahid [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

    2008-09-15

    A stack of plastic CR-39 Track Detectors were exposed to 158 A GeV {sup 207}Pb ions at the CERN-SPS beam facility. The exposure of stack was performed at normal incidence with a fluence of about 1500ions/cm{sup 2}. The total number of lead ions in each spill was about 7.8x10{sup 4} with eight spills on each stack. For the stack with the Cu target, the lengths of etched cones on one face of the CR-39 detectors (before and after the target) were measured. Using these measurements and charge identification methodology in CR-39 track detectors, total and partial charge changing cross sections of 158 A GeV Pb{sup 82+} ions on Cu and CR-39 targets are determined in the charge region 63{<=}Z{<=}82. The possibilities of presence and absence of odd-even effect in measured partial charge changing cross sections of 158 A GeV Pb ions for Cu and CR-39 targets are described. The charge resolution ({sigma}{sub Z}) achieved in the present experiment is {approx}0.18e-0.21e. The analysis of discrepancies between our experimental results and other published results for the identical reaction is also presented.

  12. Promise and Limitations of Big Data Research in Plastic Surgery.

    Science.gov (United States)

    Zhu, Victor Zhang; Tuggle, Charles Thompson; Au, Alexander Francis

    2016-04-01

    The use of "Big Data" in plastic surgery outcomes research has increased dramatically in the last 5 years. This article addresses some of the benefits and limitations of such research. This is a narrative review of large database studies in plastic surgery. There are several benefits to database research as compared with traditional forms of research, such as randomized controlled studies and cohort studies. These include the ease in patient recruitment, reduction in selection bias, and increased generalizability. As such, the types of outcomes research that are particularly suited for database studies include determination of geographic variations in practice, volume outcome analysis, evaluation of how sociodemographic factors affect access to health care, and trend analyses over time. The limitations of database research include data which are limited only to what was captured in the database, high power which can cause clinically insignificant differences to achieve statistical significance, and fishing which can lead to increased type I errors. The National Surgical Quality Improvement Project is an important general surgery database that may be useful for plastic surgeons because it is validated and has a large number of patients after over a decade of collecting data. The Tracking Operations and Outcomes for Plastic Surgeons Program is a newer database specific to plastic surgery. Databases are a powerful tool for plastic surgery outcomes research. It is critically important to understand their benefits and limitations when designing research projects or interpreting studies whose data have been drawn from them. For plastic surgeons, National Surgical Quality Improvement Project has a greater number of publications, but Tracking Operations and Outcomes for Plastic Surgeons Program is the most applicable database for plastic surgery research.

  13. Solar tracking system

    Science.gov (United States)

    Okandan, Murat; Nielson, Gregory N.

    2016-07-12

    Solar tracking systems, as well as methods of using such solar tracking systems, are disclosed. More particularly, embodiments of the solar tracking systems include lateral supports horizontally positioned between uprights to support photovoltaic modules. The lateral supports may be raised and lowered along the uprights or translated to cause the photovoltaic modules to track the moving sun.

  14. Radon diffusion studies in some building materials using solid state nuclear track detectors

    CERN Document Server

    Singh, S; Singh, B; Singh, J

    1999-01-01

    LR-115 plastic track detector has been used to study radon diffusion through some building materials, viz. cement, soil, marble chips, sand and lime as well as air. Diffusion constant and diffusion length is calculated for all these materials.

  15. Development of PNTDs synthesized from monomers with different molecular length and analysis of molecular damages by heavy ion

    International Nuclear Information System (INIS)

    Kawashima, Hajime; Kodaira, Satoshi; Ihara, Daisuke; Yasuda, Nakahiro; Kusumoto, Tamon; Mori, Yutaka; Yamauchi, Tomoya; Kobayashi, Keiichi; Benton, Eric

    2017-01-01

    Our interests for years lay to investigate the reason why CR-39 polymer has such high sensitivity as plastic nuclear track detector (PNTD) on chemical structural aspects. We developed three PNTDs from three diacrylate compounds as monomers bearing different molecular length as well as different numbers of internal ether bonds. The polymer products obtained were colorless and transparent with 3-D molecular structures as CR-39 and different lattice structures each other. Our purpose of the current study was to investigate structural damages caused in newly prepared PNTDs and CR-39 by irradiation of Nitrogen ion (6 MeV/n, fluence of 5 x 10 11 cm -2 ). The structural damage by irradiation was analyzed by the magnitude of the relative absorbance of specific functional groups such as ester, C=O, ether and C-H bonds by means of FT-IR (ATR) method. The correlation between the relative absorbance and the molecular length of the monomers were discussed. (author)

  16. Informative document waste plastics

    NARCIS (Netherlands)

    Nagelhout D; Sein AA; Duvoort GL

    1989-01-01

    This "Informative document waste plastics" forms part of a series of "informative documents waste materials". These documents are conducted by RIVM on the indstruction of the Directorate General for the Environment, Waste Materials Directorate, in behalf of the program of

  17. Art and Plastic Surgery.

    Science.gov (United States)

    Fernandes, Julio Wilson; Metka, Susanne

    2016-04-01

    The roots of science and art of plastic surgery are very antique. Anatomy, drawing, painting, and sculpting have been very important to the surgery and medicine development over the centuries. Artistic skills besides shape, volume, and lines perception can be a practical aid to the plastic surgeons' daily work. An overview about the interactions between art and plastic surgery is presented, with a few applications to rhinoplasty, cleft lip, and other reconstructive plastic surgeries. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

  18. Mesocycles in conserving plastics

    DEFF Research Database (Denmark)

    Shashoua, Yvonne

    2016-01-01

    driven by the need to balance the requirements for reversibility in conservation practices with the artist’s intent and significance. Developments within each of the three mesocycles from the 1990s to date are discussed in this article. Environmental science and toxicology of waste plastics offer a novel......Analysis suggests that progress in conservation of plastics objects and artworks can be described by a series of overlapping mesocycles. Focus has been placed for periods of 5-10 years each on determining the degradation pathways in the 1990s, developing strategies to inhibit those pathways from...... plastics has been the origin of the data describing lifetimes. By contrast, mesocycles in developing suitable storage and display microclimates for plastics have mirrored preventive conservation practices for natural polymeric materials. The rate of the third mesocycle, interventive conservation, has been...

  19. A Plastic Menagerie

    Science.gov (United States)

    Hadley, Mary Jane

    2010-01-01

    Bobble heads had become quite popular, depicting all sorts of sports figures, animals, and even presidents. In this article, the author describes how her fourth graders made bobble head sculptures out of empty plastic drink bottles. (Contains 1 online resource.)

  20. Plastic soep en Stormvogels

    OpenAIRE

    Franeker, van, J.A.; Offereins, M.; Domis, M.

    2017-01-01

    Plastic soep is een van de grootste problemen in het oppervlaktewater. Dat verschijnsel is niet nieuw; in 1997 werd al melding gemaakt van grote hoeveelheden plastic afval in het zeewater. Voor een langlopend onderzoeknaar de trends in de kwaliteit van het zeewater wordt gebruikgemaakt van de maaginhoud van aangespoelde Noordse Stormvogels. Doel van het onderzoek is een antwoord op de vraag: is door beleid en bewustwording een verbetering zichtbaar?

  1. DEVELOPMENT OF PLASTIC SURGERY.

    Science.gov (United States)

    Pećanac, Marija Đ

    2015-01-01

    Plastic surgery is a medical specialty dealing with corrections of defects, improvements in appearance and restoration of lost function. Ancient times. The first recorded account of reconstructive plastic surgery was found in ancient Indian Sanskrit texts, which described reconstructive surgeries of the nose and ears. In ancient Greece and Rome, many medicine men performed simple plastic cosmetic surgeries to repair damaged parts of the body caused by war mutilation, punishment or humiliation. In the Middle Ages, the development of all medical braches, including plastic surgery was hindered. New age. The interest in surgical reconstruction of mutilated body parts was renewed in the XVIII century by a great number of enthusiastic and charismatic surgeons, who mastered surgical disciplines and became true artists that created new forms. Modern era. In the XX century, plastic surgery developed as a modern branch in medicine including many types of reconstructive surgery, hand, head and neck surgery, microsurgery and replantation, treatment of burns and their sequelae, and esthetic surgery. Contemporary and future plastic surgery will continue to evolve and improve with regenerative medicine and tissue engineering resulting in a lot of benefits to be gained by patients in reconstruction after body trauma, oncology amputation, and for congenital disfigurement and dysfunction.

  2. Sorting Plastic Waste in Hydrocyclone

    Directory of Open Access Journals (Sweden)

    Ernestas Šutinys

    2011-02-01

    Full Text Available The article presents material about sorting plastic waste in hydrocyclone. The tests on sorting plastic waste were carried out. Also, the findings received from the performed experiment on the technology of sorting plastic waste are interpreted applying an experimental model of the equipment used for sorting plastics of different density.Article in Lithuanian

  3. The Need for Plastics Education.

    Science.gov (United States)

    Society of Plastics Engineers, Inc., Stamford, CT.

    In view of a lack of trained personnel in the industry, the Plastics Education Foundation proposes that educators (1) add more plastics programs, (2) establish plastics engineering degrees at appropriate 4-year institutions, (3) add plastics processing technology to current engineering curricula, and (4) interest younger students in courses and/or…

  4. 77 FR 54930 - Carlyle Plastics and Resins, Formerly Known as Fortis Plastics, A Subsidiary of Plastics...

    Science.gov (United States)

    2012-09-06

    ... Employment and Training Administration Carlyle Plastics and Resins, Formerly Known as Fortis Plastics, A Subsidiary of Plastics Acquisitions Inc., Including On-Site Leased Workers From Kelly Services and Shelley... Adjustment Assistance on July 3, 2012, applicable to workers and former workers of workers of Fortis Plastics...

  5. Renewable Energy Tracking Systems

    Science.gov (United States)

    Renewable energy generation ownership can be accounted through tracking systems. Tracking systems are highly automated, contain specific information about each MWh, and are accessible over the internet to market participants.

  6. Forward tracking detectors

    Indian Academy of Sciences (India)

    Abstract. Forward tracking is an essential part of a detector at the international linear collider (ILC). The requirements for forward tracking are explained and the proposed solutions in the detector concepts are shown.

  7. The development of a personal dosemeter for use by aircraft crew

    International Nuclear Information System (INIS)

    Stokes, R.P.; Talbot, L.

    2000-01-01

    This paper describes preliminary work to develop a cosmic-radiation dosemeter for use by military aircraft crew. The dosemeter is based on a combination of CR-39 etched-track detectors and TLD-700 thermoluminescent detectors. It is intended that the CR-39 be used to assess the neutron dose, while the TLD-700 is used to assess the photon and charged particle dose. The sensitivity of CR-39 to the neutron component of cosmic radiation was estimated by irradiating samples of the plastic at the CERN-CEC High Energy Reference Field Facility. This facility produced a radiation field with a neutron spectrum resembling that of the neutron component of cosmic radiation a typical airflight altitudes. The response of the CR-39 was linear over the range of doses studied (0.2-6.0 mSv) and there was no significant fading in the six-month period after irradiation. The TLD-700 component of the dosemeter was calibrated using 137 Cs gamma rays. The response of the TLD-700 was linear over the range of doses studied (0-1.1 mSv) with no significant fade in the six-month period after irradiation. It was concluded that a combination of CR-39 and TLD-700 detectors would provide an effective cosmic-radiation dosemeter for use by military aircraft crew. (author)

  8. Plastic Organic Scintillator Chemistry

    Science.gov (United States)

    Brightwell, C. R.; Temanson, E. S.; Febbraro, M. T.

    2017-09-01

    Due to their high light output, quick decay time, affordability, durability and ability to be molded, plastic organic scintillators are increasingly becoming a more viable method of particle detection. Since the plastic is composed entirely of single molecular chains with repeating units, scintillating properties remain stable despite changes in experimental conditions. Different scintillating plastics can be modified and tailored to suit specific experiments depending on a variety of requirements such as light output, scintillating wavelength, and PMT compatibility. The synthesis chemistry of a recent but well-known scintillating polyester, polyethylene naphthalate (PEN) will be presented to demonstrate how plastic organic scintillators can be modified for different particle detection experiments. PEN has been successfully synthesized at ORNL, and procedures are currently being investigated to modify PEN using different reactants and catalysts. The goal is to achieve a transparent scintillating plastic with an incorporated wavelength shifter in the chain that scintillates with a wavelength around 440 nm. The status of this project will be presented. This research is supported by the U. S. Department of Energy Office of Science.

  9. The influence of the soil and plant natures and pollution on the radon and thoron alpha-activities inside various herbal infusions by using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Nouh, F.A.; Bourzik, W.

    2001-01-01

    Uranium and thorium contents were determined in samples of various plants in the soils in which the plants were grown, and in herbal infusions made by boiling the plants in potable water, using CR-39 and LR-115 solid state nuclear track detectors. In addition, radon and thoron alpha-activities per unit volume inside the plants, soils and herbal infusions were measured. These measurements were completed by an investigation of the radon transfer between soils and plants and that between plants and herbal infusions, and also by the investigation of the influence of pollution due to different material dusts on the radon and thoron alpha activities inside the plants and their infusions. (author)

  10. Eye Tracking for Everyone

    OpenAIRE

    Kellnhofer, Petr; Bhandarkar, Suchendra; Khosla, Aditya; Kannan, Harini D.; Matusik, Wojciech; Torralba, Antonio

    2016-01-01

    From scientific research to commercial applications, eye tracking is an important tool across many domains. Despite its range of applications, eye tracking has yet to become a pervasive technology. We believe that we can put the power of eye tracking in everyone's palm by building eye tracking software that works on commodity hardware such as mobile phones and tablets, without the need for additional sensors or devices. We tackle this problem by introducing GazeCapture, the first large-scale ...

  11. HLT Track Reconstruction Performance

    CERN Document Server

    The ATLAS Collaboration

    2009-01-01

    This note reviews the tracking algorithms used at the L2 and Event Filter stages of the High Level Trigger of ATLAS. The tracking performance (efficiency, resolution) is studied for different topologies (single tracks, high and low pt jets) using simulated data. Detailed information on the execution time of the algorithms is also given.

  12. Performance of ATLAS tracking

    CERN Document Server

    Roe, Shaun; The ATLAS collaboration

    2017-01-01

    Run-2 of the Large Hadron Collider (LHC) has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity envi-ronments. This talk provides an overview of the tracking performance, highlighting tracking improvements due to the Insertable B-Layer (IBL) and the introduction of time-dependent alignment.

  13. Asset tracking in harsh environments

    Energy Technology Data Exchange (ETDEWEB)

    O' Neal, E.S. [Infosight Corp., Chillicothe, OH (United States)

    2009-07-01

    Current economic times require tight control of all assets / inventory and processes a company manages. These items if managed correctly and timely can mean the difference between success and failure of a company. Cost savings in hard economic times are essential to allow a company to utilize its assets to the fullest potential by eliminating duplication and waste. Accurate process management leads to greater customer satisfaction and loyalty. Many industries and processes have believed it to be impossible to track their products or assets using bar-codes due to the unique conditions of their environment; whether it is high temperature, rough handling or chemicals. That has now changed. Companies specializing in identification methods have stepped up to the challenge and have overcome many obstacles of the past. It's no longer a paper or plastic bar-code world. The presentation will be broken down into four parts: 1) The differences between Asset and ID tracking; 2) Why does a company need to bar-code?; 3) The objections many companies use for not bar-coding; and, 4) What's new in bar-coding? Case study handouts and a reference list of various companies including software, labeling and attachment techniques will be available at the end of the presentation. (author)

  14. Asset tracking in harsh environments

    International Nuclear Information System (INIS)

    O'Neal, E.S.

    2009-01-01

    Current economic times require tight control of all assets / inventory and processes a company manages. These items if managed correctly and timely can mean the difference between success and failure of a company. Cost savings in hard economic times are essential to allow a company to utilize its assets to the fullest potential by eliminating duplication and waste. Accurate process management leads to greater customer satisfaction and loyalty. Many industries and processes have believed it to be impossible to track their products or assets using bar-codes due to the unique conditions of their environment; whether it is high temperature, rough handling or chemicals. That has now changed. Companies specializing in identification methods have stepped up to the challenge and have overcome many obstacles of the past. It's no longer a paper or plastic bar-code world. The presentation will be broken down into four parts: 1) The differences between Asset and ID tracking; 2) Why does a company need to bar-code?; 3) The objections many companies use for not bar-coding; and, 4) What's new in bar-coding? Case study handouts and a reference list of various companies including software, labeling and attachment techniques will be available at the end of the presentation. (author)

  15. Elastic plastic fracture mechanics

    International Nuclear Information System (INIS)

    Simpson, L.A.

    1978-07-01

    The application of linear elastic fracture mechanics (LEFM) to crack stability in brittle structures is now well understood and widely applied. However, in many structural materials, crack propagation is accompanied by considerable crack-tip plasticity which invalidates the use of LEFM. Thus, present day research in fracture mechanics is aimed at developing parameters for predicting crack propagation under elastic-plastic conditions. These include critical crack-opening-displacement methods, the J integral and R-curve techniques. This report provides an introduction to these concepts and gives some examples of their applications. (author)

  16. Investigation into Plastic Cards

    Directory of Open Access Journals (Sweden)

    Neringa Stašelytė

    2015-03-01

    Full Text Available The article examines the strength of laminating plastic cards at different lamination temperatures. For investigation purposes, two types of plastic substrate and films have been used. Laminate strength has been tested (CMYK to establish the impact of colours on the strength of laminate. The paper compares inks supplied by two different producers. The colour characteristics of CIE L*a*b* space before and after the lamination process have been found. According to lamination strength and characteristics of the colours, the most suitable inks, temperature and films have been chosen.

  17. Science and technology with nuclear tracks in solids

    CERN Document Server

    Buford-Price, P

    2005-01-01

    Fission track dating has greatly expanded its usefulness to geology over the last 40 years. It is central to thermochronology—the use of shortened fission tracks to decipher the thermal history, movement, and provenance of rocks. When combined with other indicators, such as zircon color and (U–Th)/He, a range of temperatures from C to C can be studied. Combining fission track analysis with cosmogenic nuclide decay rates, one can study landscape development and denudation of passive margins. Technological applications have expanded from biological filters, radon mapping, and dosimetry to the use of ion track microtechnology in microlithography, micromachining by ion track etching, microscopic field emission tips, magnetic nanowires as magnetoresistive sensors, microfluidic devices, physiology of ion channels in single cells, and so on. In nuclear and particle physics, relatively insensitive glass detectors have been almost single-handedly responsible for our knowledge of cluster radioactivity, and plastic ...

  18. Recycling of plastics in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Masaki, K. [Clean Japan Center, Tokyo (Japan). PET Bottle Recycling Project Dept.

    1998-10-01

    The Clean Japan Center is an NGO concerned with recycling. This article presents an overview of methods for recyling products made of various types of plastic. A number of such methods are in use or being studied. Emphasis is given to the state of plastics recycling in Japan. The uses of waste plastics as materials in other industrials is outlined - these include waste plastics as a reducer in blast furnaces, replacing coke and pulverized coal; waste plastics as a source of heat in cement kilns as an alternative to pulverized coal; and waste plastics being incinerated to generate power. 3 figs.

  19. Tracking by Neural Nets

    CERN Document Server

    Jofrehei, Arash

    2015-01-01

    Current track reconstruction methods start with two points and then for each layer loop through all possible hits to find proper hits to add to that track. Another idea would be to use this large number of already reconstructed events and/or simulated data and train a machine on this data to find tracks given hit pixels. Training time could be long but real time tracking is really fast. Simulation might not be as realistic as real data but tracking efficiency is 100 percent for that while by using real data we would probably be limited to current efficiency. The fact that this approach can be a lot faster and even more efficient than current methods by using simulation data can make it a great alternative for current track reconstruction methods used in both triggering and tracking.

  20. Advanced Tracking of Vehicles

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Li, K.-J.; Pakalnis, Stardas

    2005-01-01

    With the continued advances in wireless communications, geo-location technologies, and consumer electronics, it is becoming possible to accurately track the time-varying location of each vehicle in a population of vehicles. This paper reports on ongoing research that has as it objective to develop...... efficient tracking techniques. More specifically, while almost all commercially available tracking solutions simply offer time-based sampling of positions, this paper's techniques aim to offer a guaranteed tracking accuracy for each vehicle at the lowest possible costs, in terms of network traffic...... and server-side updates. This is achieved by designing, prototyping, and testing novel tracking techniques that exploit knowledge of the road network and past movement. These resulting tracking techniques are to support mobile services that rely on the existence of a central server that continuously tracks...

  1. Tracks: Nurses and the Tracking Network

    Centers for Disease Control (CDC) Podcasts

    2012-06-06

    This podcast highlights the utility of the National Environmental Public Health Tracking Network for nurses in a variety of work settings. It features commentary from the American Nurses Association and includes stories from a public health nurse in Massachusetts.  Created: 6/6/2012 by National Center for Environmental Health (NCEH)/Division of Environmental Hazards and Health Effects (DEHHE)/Environmental Health Tracking Branch (EHTB).   Date Released: 6/6/2012.

  2. Predictors of Readmission after Inpatient Plastic Surgery

    Science.gov (United States)

    Jain, Umang; Salgado, Christopher; Mioton, Lauren; Rambachan, Aksharananda

    2014-01-01

    Background Understanding risk factors that increase readmission rates may help enhance patient education and set system-wide expectations. We aimed to provide benchmark data on causes and predictors of readmission following inpatient plastic surgery. Methods The 2011 National Surgical Quality Improvement Program dataset was reviewed for patients with both "Plastics" as their recorded surgical specialty and inpatient status. Readmission was tracked through the "Unplanned Readmission" variable. Patient characteristics and outcomes were compared using chi-squared analysis and Student's t-tests for categorical and continuous variables, respectively. Multivariate regression analysis was used for identifying predictors of readmission. Results A total of 3,671 inpatient plastic surgery patients were included. The unplanned readmission rate was 7.11%. Multivariate regression analysis revealed a history of chronic obstructive pulmonary disease (COPD) (odds ratio [OR], 2.01; confidence interval [CI], 1.12-3.60; P=0.020), previous percutaneous coronary intervention (PCI) (OR, 2.69; CI, 1.21-5.97; P=0.015), hypertension requiring medication (OR, 1.65; CI, 1.22-2.24; Pplastic surgery has an associated 7.11% unplanned readmission rate. History of COPD, previous PCI, hypertension, ASA class 3 or 4, bleeding disorders, and obesity all proved to be significant risk factors for readmission. These findings will help to benchmark inpatient readmission rates and manage patient and hospital system expectations. PMID:24665418

  3. Individual differences in behavioural plasticities.

    Science.gov (United States)

    Stamps, Judy A

    2016-05-01

    Interest in individual differences in animal behavioural plasticities has surged in recent years, but research in this area has been hampered by semantic confusion as different investigators use the same terms (e.g. plasticity, flexibility, responsiveness) to refer to different phenomena. The first goal of this review is to suggest a framework for categorizing the many different types of behavioural plasticities, describe examples of each, and indicate why using reversibility as a criterion for categorizing behavioural plasticities is problematic. This framework is then used to address a number of timely questions about individual differences in behavioural plasticities. One set of questions concerns the experimental designs that can be used to study individual differences in various types of behavioural plasticities. Although within-individual designs are the default option for empirical studies of many types of behavioural plasticities, in some situations (e.g. when experience at an early age affects the behaviour expressed at subsequent ages), 'replicate individual' designs can provide useful insights into individual differences in behavioural plasticities. To date, researchers using within-individual and replicate individual designs have documented individual differences in all of the major categories of behavioural plasticities described herein. Another important question is whether and how different types of behavioural plasticities are related to one another. Currently there is empirical evidence that many behavioural plasticities [e.g. contextual plasticity, learning rates, IIV (intra-individual variability), endogenous plasticities, ontogenetic plasticities) can themselves vary as a function of experiences earlier in life, that is, many types of behavioural plasticity are themselves developmentally plastic. These findings support the assumption that differences among individuals in prior experiences may contribute to individual differences in behavioural

  4. Thermodynamics of perfect plasticity

    Czech Academy of Sciences Publication Activity Database

    Roubíček, Tomáš

    2013-01-01

    Roč. 6, č. 1 (2013), s. 193-214 ISSN 1937-1632 R&D Projects: GA ČR GAP201/10/0357 Institutional support: RVO:61388998 Keywords : Prandtl-Reuss plasticity * small strains * Kelvin-Voigt rheology Subject RIV: BA - General Mathematics http://aimsciences.org/journals/home.jsp?journalID=15

  5. Plastic Surgery: Tackling Misconceptions

    African Journals Online (AJOL)

    will succeed. First impressions tend to last, and if young people's first impression of plastic surgeons is that they spend much of their time doing cosmetic surgery then this is a first impression that might be long ... Res 2014;4 Suppl S3:169‑70. Access this article online. Quick Response Code: Website: www.amhsr.org. DOI:.

  6. New plastic recycling technology

    Science.gov (United States)

    Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy de...

  7. Challenges in plastics recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann

    2015-01-01

    Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study wa...

  8. Reliability of Plastic Slabs

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    1989-01-01

    In the paper it is shown how upper and lower bounds for the reliability of plastic slabs can be determined. For the fundamental case it is shown that optimal bounds of a deterministic and a stochastic analysis are obtained on the basis of the same failure mechanisms and the same stress fields....

  9. An automated neutron dosimetry system based on the chemical etch of CR-39

    International Nuclear Information System (INIS)

    Harvey, J.R.; French, A.P.; Jackson, M.; Weeks, A.R.

    1997-01-01

    The dosimetric characteristics of two types of personal neutron dosemeter have recently been extensively assessed. The effects of exposure to various extreme environments have also been studied. Both types of dosemeter utilise chemically etched elements which are read in an automated reader, the Autoscan 60, which uses an edge illumination system to increase the pit image size. One type of dosemeter contains three elements in a pyramid structure. The other uses one or two elements in a planar structure. The results indicate that both types of dosemeter can be used to assess accurately the personal dose from neutrons in a range of harsh environments. Formal approval for the operational use of the system has been received. (author)

  10. Indoor radon and radon daughters survey at Campinas-Brazil using CR-39: First results

    CERN Document Server

    Guedes, S; Iunes, P J; Navia, L M S; Neman, R S; Paulo, S R; Rodrigues, V C; Souza, W F; Tello, C A S; Zúñiga, A G

    1999-01-01

    The first results of a radon and radon daughters (RD) survey performed at Campinas-SP, Brazil, are presented. We employed a technique that, potentially, makes possible to measure the radon and RD activity in the air and to separate from this result the activity of radon, alone. In this preliminary paper only the former activity is studied.

  11. Investigations of doses on board commercial passenger aircraft using CR-39 and thermoluminescent detectors

    Czech Academy of Sciences Publication Activity Database

    Horwacik, T.; Bilski, P.; Olko, P.; Spurný, František; Turek, Karel

    2004-01-01

    Roč. 110, 1-4 (2004), s. 377-380 ISSN 0144-8420 Grant - others:EC project(XE) FIGM-CT2000-00068 Institutional research plan: CEZ:AV0Z1048901 Keywords : Aircrew * thermoluminescent detectors * environmental measurements Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.617, year: 2003

  12. Green’s function molecular dynamics meets discrete dislocation plasticity

    Science.gov (United States)

    Venugopalan, Syam P.; Müser, Martin H.; Nicola, Lucia

    2017-09-01

    Metals deform plastically at the asperity level when brought in contact with a counter body even when the nominal contact pressure is small. Modeling the plasticity of solids with rough surfaces is challenging due to the multi-scale nature of surface roughness and the length-scale dependence of plasticity. While discrete-dislocation plasticity (DDP) simulations capture size-dependent plasticity by keeping track of the motion of individual dislocations, only simple two-dimensional surface geometries have so far been studied with DDP. The main computational bottleneck in contact problems modeled by DDP is the calculation of the dislocation image fields. We address this issue by combining two-dimensional DDP with Green’s function molecular dynamics. The resulting method allows for an efficient boundary-value-method based treatment of elasticity in the presence of dislocations. We demonstrate that our method captures plasticity quantitatively from single to many dislocations and that it scales more favorably with system size than conventional methods. We also derive the relevant Green’s functions for elastic slabs of finite width allowing arbitrary boundary conditions on top and bottom surface to be simulated.

  13. Plasticity-induced restructuring of a nanocrystalline grain boundary network

    International Nuclear Information System (INIS)

    Panzarino, Jason F.; Pan, Zhiliang; Rupert, Timothy J.

    2016-01-01

    The grain boundary-mediated mechanisms that control plastic deformation of nanocrystalline metals should cause evolution of the grain boundary network, since they directly alter misorientation relationships between crystals. Unfortunately, current experimental techniques are unable to track such evolution, due to limits on both spatial and temporal resolution. In this work, molecular dynamics simulations are used to study grain boundary restructuring in nanocrystalline Al during both monotonic tension and cyclic loading. This task is enabled by the creation of new analysis tools for atomistic datasets that allow for a complete characterization and tracking of microstructural descriptors of the grain boundary network. Quantitative measurements of grain boundary character distribution, triple junction type, grain boundary plane normal, and other interfacial network characteristics are extracted and analyzed. The results presented here show that nanocrystalline plasticity leads to an increase in special boundary fraction and disruption of two-dimensional boundary connectivity, with the most dramatic evolution occurring in the smallest grain sizes.

  14. Predictors of Readmission after Inpatient Plastic Surgery

    Directory of Open Access Journals (Sweden)

    Umang Jain

    2014-03-01

    Full Text Available Background Understanding risk factors that increase readmission rates may help enhance patient education and set system-wide expectations. We aimed to provide benchmark data on causes and predictors of readmission following inpatient plastic surgery. Methods The 2011 National Surgical Quality Improvement Program dataset was reviewed for patients with both "Plastics" as their recorded surgical specialty and inpatient status. Readmission was tracked through the "Unplanned Readmission" variable. Patient characteristics and outcomes were compared using chi-squared analysis and Student's t-tests for categorical and continuous variables, respectively. Multivariate regression analysis was used for identifying predictors of readmission. Results A total of 3,671 inpatient plastic surgery patients were included. The unplanned readmission rate was 7.11%. Multivariate regression analysis revealed a history of chronic obstructive pulmonary disease (COPD (odds ratio [OR], 2.01; confidence interval [CI], 1.12-3.60; P=0.020, previous percutaneous coronary intervention (PCI (OR, 2.69; CI, 1.21-5.97; P=0.015, hypertension requiring medication (OR, 1.65; CI, 1.22-2.24; P<0.001, bleeding disorders (OR, 1.70; CI, 1.01-2.87; P=0.046, American Society of Anesthesiologists (ASA class 3 or 4 (OR, 1.57; CI, 1.15-2.15; P=0.004, and obesity (body mass index ≥30 (OR, 1.43; CI, 1.09-1.88, P=0.011 to be significant predictors of readmission. Conclusions Inpatient plastic surgery has an associated 7.11% unplanned readmission rate. History of COPD, previous PCI, hypertension, ASA class 3 or 4, bleeding disorders, and obesity all proved to be significant risk factors for readmission. These findings will help to benchmark inpatient readmission rates and manage patient and hospital system expectations.

  15. Finding the missing plastic -resolving the global mass (im)balance for plastic pollution in the ocean

    Science.gov (United States)

    Wilcox, C.; van Sebille, E.

    2016-02-01

    Several global studies have attempted to estimate the standing stock of plastic debris in the oceans at the global scale. However, recent work estimating the amount lost from land on an annual basis suggests that the standing stock should be several orders of magnitude larger than the global estimates. We investigate the role of coastal deposition within the first few weeks after plastic enters the ocean and very near its sources, one of the hypothesized sinks for the missing plastic in this mass balance. We utilize a continental scale dataset of plastics collected along Australia's coast and in the offshore regions together with models of plastic release and transport based on Lagrangian tracking to investigate the role of local deposition in the coastal environment. Our models predict that the vast majority of positively buoyant plastic is deposited within a very short distance from its release point, with only a small fraction escaping into the open ocean. These predictions match our coastal and offshore observations, providing clear evidence that this mechanism of immediate coastal deposition is, at least in part, driving the apparent mismatch between coastal emissions and the standing stock in the ocean.

  16. Introduction to Computational Plasticity

    International Nuclear Information System (INIS)

    Hartley, P

    2006-01-01

    The focus of the book on computational plasticity embodies techniques of relevance not only to academic researchers, but also of interest to industrialists engaged in the production of components using bulk or sheet forming processes. Of particular interest is the guidance on how to create modules for use with the commercial system Abaqus for specific types of material behaviour. The book is in two parts, the first of which contains six chapters, starting with microplasticity, but predominantly on continuum plasticity. The first chapter on microplasticty gives a brief description of the grain structure of metals and the existence of slip systems within the grains. This provides an introduction to the concept of incompressibility during plastic deformation, the nature of plastic yield and the importance of the critically resolved shear stress on the slip planes (Schmid's law). Some knowledge of the notation commonly used to describe slip systems is assumed, which will be familiar to students of metallurgy, but anyone with a more general engineering background may need to undertake additional reading to understand the various descriptions. Chapter two introduces one of several yield criteria, that normally attributed to von Mises (though historians of mechanics might argue over who was first to develop the theory of yielding associated with strain energy density), and its two or three-dimensional representation as a yield surface. The expansion of the yield surface during plastic deformation, its translation due to kinematic hardening and the Bauschinger effect in reversed loading are described with a direct link to the material stress-strain curve. The assumption, that the increment of strain is normal to the yield surface, the normality principle, is introduced. Uniaxial loading of an elastic-plastic material is used as an example in which to develop expressions to describe increments in stress and strain. The full presentation of numerous expressions, tensors and

  17. DCS Budget Tracking System

    Data.gov (United States)

    Social Security Administration — DCS Budget Tracking System database contains budget information for the Information Technology budget and the 'Other Objects' budget. This data allows for monitoring...

  18. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1976-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  19. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1977-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  20. Plasticity modeling & computation

    CERN Document Server

    Borja, Ronaldo I

    2013-01-01

    There have been many excellent books written on the subject of plastic deformation in solids, but rarely can one find a textbook on this subject. “Plasticity Modeling & Computation” is a textbook written specifically for students who want to learn the theoretical, mathematical, and computational aspects of inelastic deformation in solids. It adopts a simple narrative style that is not mathematically overbearing, and has been written to emulate a professor giving a lecture on this subject inside a classroom. Each section is written to provide a balance between the relevant equations and the explanations behind them. Where relevant, sections end with one or more exercises designed to reinforce the understanding of the “lecture.” Color figures enhance the presentation and make the book very pleasant to read. For professors planning to use this textbook for their classes, the contents are sufficient for Parts A and B that can be taught in sequence over a period of two semesters or quarters.

  1. Nanotechnology in plastic surgery.

    Science.gov (United States)

    Ibrahim, Ahmed M S; Gerstle, Theodore L; Rabie, Amr N; Song, Yong-Ak; Melik, Rohat; Han, Jongyoon; Lin, Samuel J

    2012-12-01

    Nanotechnology has made inroads over time within surgery and medicine. Translational medical devices and therapies based on nanotechnology are being developed and put into practice. In plastic surgery, it is anticipated that this new technology may be instrumental in the future. Microelectromechanical systems are one form of nanotechnology that offers the ability to develop miniaturized implants for use in the treatment of numerous clinical conditions. The authors summarize their published preliminary findings regarding a microelectromechanical systems-based electrochemical stimulation method through modulation of ions around the nerve that is potentially implantable and clinically efficacious, and expand upon current and potential usages of nanotechnology in plastic surgery. Sciatic nerves (n = 100) of 50 American bullfrogs were placed on a microfabricated planar gold electrode array and stimulated electrically. Using Ca(2+)-selective membranes, ion concentrations were modulated around the nerve environment in situ. In addition, a comprehensive review of the literature was performed to identify all available data pertaining to the use of nanotechnology in medicine. A 40 percent reduction of the electrical threshold value was observed using the Ca(2+) ion-selective membrane. The uses of nanotechnology specifically applicable to plastic surgery are detailed. Nanotechnology may likely lead to advancements in the art and science of plastic surgery. Using microelectromechanical systems nanotechnology, the authors have demonstrated a novel means of modulating the activation of nerve impulses. These findings have potentially significant implications for the design of special nano-enhanced materials that can be used to promote healing, control infection, restore function, and aid nerve regeneration and rehabilitation.

  2. New heavy plastic scintillators

    International Nuclear Information System (INIS)

    Britvich, G.I.; Vasil'chenko, V.G.; Lapshin, V.G.; Solov'ev, A.S.

    2000-01-01

    The possibility of manufacturing through the quenching method new transparent heavy scintillators on the basis of polystyrene with the light yield of approximately 32% from anthracene by general concentration of metalloorganic additions of approximately 17% by weight is shown. Doping of plastic scintillators through a set of various metalloorganic additives makes it possible to achieve more efficient and homogeneous by energy absorption of soft γ-quanta therein [ru

  3. Synthesis of SYEP Plasticizer

    Science.gov (United States)

    1975-10-01

    mmm ^ Unclassified —..■■.■„ 5 .»„.^TmN OF THIS MiiCg P«" BSg (20) Abstract K* •** *~ «• K? "involved a 6cale"up oieration vhloh resu1’ ted in...Fluorochem, RPL, and Lawrence Llvermore Laboratory Indicate that SYEP possesses suitable chemical and physical properties for a high energy plasticizer

  4. New perspectives in plastic biodegradation.

    Science.gov (United States)

    Sivan, Alex

    2011-06-01

    During the past 50 years new plastic materials, in various applications, have gradually replaced the traditional metal, wood, leather materials. Ironically, the most preferred property of plastics--durability--exerts also the major environmental threat. Recycling has practically failed to provide a safe solution for disposal of plastic waste (only 5% out of 1 trillion plastic bags, annually produced in the US alone, are being recycled). Since the most utilized plastic is polyethylene (PE; ca. 140 million tons/year), any reduction in the accumulation of PE waste alone would have a major impact on the overall reduction of the plastic waste in the environment. Since PE is considered to be practically inert, efforts were made to isolate unique microorganisms capable of utilizing synthetic polymers. Recent data showed that biodegradation of plastic waste with selected microbial strains became a viable solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Performance of molded plastic scintillators

    International Nuclear Information System (INIS)

    Gen, N.S.; Leman, V.E.; Solomonov, V.M.

    1989-01-01

    The performance of molded plastic scintillators is studied. The plastic scintillators studied were formed by transfer molding and intrusion from a scintillation composition consisting of polystyrene and a standard system of luminescent additives: 2 mass % of paraterphenyl + 0.06 mass % 1,4-di-/2-[5-phenyloxazoyly]/benzene and a plasticizer. The combined effect of mechanical load and temperature was studied. The effect of radiation on molded plastic scintillators was studied using gamma radiation from a 60 Co source. The studies show that the main operating characteristics of molded plastic scintillators are on a par with those of polymerized plastic scintillators. At the same time, molded plastic scintillators are superior in thermal stability at temperatures below the glass transition temperature and with respect to their working temperature range

  6. Microelectronics plastic molded packaging

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.R. [Ktech Corp., Albuquerque, NM (United States); Palmer, D.W.; Peterson, D.W. [Sandia National Lab., Albuquerque, NM (United States)] [and others

    1997-02-01

    The use of commercial off-the-shelf (COTS) microelectronics for nuclear weapon applications will soon be reality rather than hearsay. The use of COTS for new technologies for uniquely military applications is being driven by the so-called Perry Initiative that requires the U.S. Department of Defense (DoD) to accept and utilize commercial standards for procurement of military systems. Based on this philosophy, coupled with several practical considerations, new weapons systems as well as future upgrades will contain plastic encapsulated microelectronics. However, a conservative Department of Energy (DOE) approach requires lifetime predictive models. Thus, the focus of the current project is on accelerated testing to advance current aging models as well as on the development of the methodology to be used during WR qualification of plastic encapsulated microelectronics. An additional focal point involves achieving awareness of commercial capabilities, materials, and processes. One of the major outcomes of the project has been the definition of proper techniques for handling and evaluation of modern surface mount parts which might be used in future systems. This program is also raising the familiarity level of plastic within the weapons complex, allowing subsystem design rules accommodating COTS to evolve. A two year program plan is presented along with test results and commercial interactions during this first year.

  7. Respiratory Muscle Plasticity

    Science.gov (United States)

    Gransee, Heather M.; Mantilla, Carlos B.; Sieck, Gary C.

    2014-01-01

    Muscle plasticity is defined as the ability of a given muscle to alter its structural and functional properties in accordance with the environmental conditions imposed on it. As such, respiratory muscle is in a constant state of remodeling, and the basis of muscle’s plasticity is its ability to change protein expression and resultant protein balance in response to varying environmental conditions. Here, we will describe the changes of respiratory muscle imposed by extrinsic changes in mechanical load, activity, and innervation. Although there is a large body of literature on the structural and functional plasticity of respiratory muscles, we are only beginning to understand the molecular-scale protein changes that contribute to protein balance. We will give an overview of key mechanisms regulating protein synthesis and protein degradation, as well as the complex interactions between them. We suggest future application of a systems biology approach that would develop a mathematical model of protein balance and greatly improve treatments in a variety of clinical settings related to maintaining both muscle mass and optimal contractile function of respiratory muscles. PMID:23798306

  8. Search for Fractionally Charged Nuclei in High-Energy Oxygen-Lead Collisions

    CERN Multimedia

    2002-01-01

    We propose to use stacks of CR-39 plastic track detectors to look for fractionally charged projectile fragments produced in collisions of high-energy oxygen, sulfur, and calcium nuclei with a lead target. The expected charge resolution is @s^z~=~0.06e for fragments with 17e/3~@$<$~Z~@$<$~23e/3. We request that two target + stack assemblies be exposed to 1~x~10|5 oxygen nuclei at maximum available energy.

  9. Homologous recombination in Arabidopsis seeds along the track of energetic carbon ions

    International Nuclear Information System (INIS)

    Wang Ting; Li Fanghua; Liu Qingfang; Bian Po; Wang Jufang; Wu Yuejin; Wu Lijun; Li Wenjian

    2012-01-01

    Heavy ion irradiation has been used as radiotherapy of deep-seated tumors, and is also an inevitable health concern for astronauts in space mission. Unlike photons such as X-rays and γ-rays, a high linear energy transfer (LET) heavy ion has a varying energy distribution along its track. Therefore, it is important to determine the correlation of biological effects with the Bragg curve energy distribution of heavy ions. In this study, a continuous biological tissue equivalent was constructed using a layered cylinder of Arabidopsis seeds, which was irradiated with carbon ions of 87.5 MeV/nucleon. The position of energy loss peak in the seed pool was determined with CR-39 track detectors. The mutagenic effect in vivo along the path of carbon ions was investigated with the seeds in each layer as an assay unit, which corresponded to a given position in physical Bragg curve. Homologous recombination frequency (HRF), expression level of AtRAD54 gene, germination rate of seeds, and survival rate of young seedlings were used as checking endpoints, respectively. Our results showed that Arabidopsis S0 and S1 plants exhibited significant increases in HRF compared to their controls, and the expression level of AtRAD54 gene in S0 plants was significantly up-regulated. The depth-biological effect curves for HRF and the expression of AtRAD54 gene were not consistent with the physical Bragg curve. Differently, the depth-biological effect curves for the developmental endpoints matched generally with the physical Bragg curve. The results suggested a different response pattern of various types of biological events to heavy ion irradiation. It is also interesting that except for HRF in S0 plants, the depth-biological effect curves for each biological endpoint were similar for 5 Gy and 30 Gy of carbon irradiation.

  10. Interfacial interactions between plastic particles in plastics flotation.

    Science.gov (United States)

    Wang, Chong-qing; Wang, Hui; Gu, Guo-hua; Fu, Jian-gang; Lin, Qing-quan; Liu, You-nian

    2015-12-01

    Plastics flotation used for recycling of plastic wastes receives increasing attention for its industrial application. In order to study the mechanism of plastics flotation, the interfacial interactions between plastic particles in flotation system were investigated through calculation of Lifshitz-van der Waals (LW) function, Lewis acid-base (AB) Gibbs function, and the extended Derjaguin-Landau-Verwey-Overbeek potential energy profiles. The results showed that van der Waals force between plastic particles is attraction force in flotation system. The large hydrophobic attraction, caused by the AB Gibbs function, is the dominant interparticle force. Wetting agents present significant effects on the interfacial interactions between plastic particles. It is found that adsorption of wetting agents promotes dispersion of plastic particles and decreases the floatability. Pneumatic flotation may improve the recovery and purity of separated plastics through selective adsorption of wetting agents on plastic surface. The relationships between hydrophobic attraction and surface properties were also examined. It is revealed that there exists a three-order polynomial relationship between the AB Gibbs function and Lewis base component. Our finding provides some insights into mechanism of plastics flotation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. CWI at TREC 2012, KBA track and Session Track

    NARCIS (Netherlands)

    S. Araújo (Samur); C. Boscarino (Corrado); G.G. Gebremeskel (Gebre); J. He (Jiyin); A.P. de Vries (Arjen); E.M. Voorhees; L. P. Buckland (Buckland, Lori P.)

    2013-01-01

    htmlabstractWe participated in two tracks: Knowledge Base Acceleration (KBA) Track and Session Track. In the KBA track, we focused on experi- menting with different approaches as it is the first time the track is launched. We experimented with supervised and unsupervised re- trieval models. Our

  12. Incentives from Curriculum Tracking

    Science.gov (United States)

    Koerselman, Kristian

    2013-01-01

    Curriculum tracking creates incentives in the years before its start, and we should therefore expect test scores to be higher during those years. I find robust evidence for incentive effects of tracking in the UK based on the UK comprehensive school reform. Results from the Swedish comprehensive school reform are inconclusive. Internationally, I…

  13. UWB Tracking Software Development

    Science.gov (United States)

    Gross, Julia; Arndt, Dickey; Ngo, Phong; Phan, Chau; Dusl, John; Ni, Jianjun; Rafford, Melinda

    2006-01-01

    An Ultra-Wideband (UWB) two-cluster Angle of Arrival (AOA) tracking prototype system is currently being developed and tested at NASA Johnson Space Center for space exploration applications. This talk discusses the software development efforts for this UWB two-cluster AOA tracking system. The role the software plays in this system is to take waveform data from two UWB radio receivers as an input, feed this input into an AOA tracking algorithm, and generate the target position as an output. The architecture of the software (Input/Output Interface and Algorithm Core) will be introduced in this talk. The development of this software has three phases. In Phase I, the software is mostly Matlab driven and calls C++ socket functions to provide the communication links to the radios. This is beneficial in the early stage when it is necessary to frequently test changes in the algorithm. Phase II of the development is to have the software mostly C++ driven and call a Matlab function for the AOA tracking algorithm. This is beneficial in order to send the tracking results to other systems and also to improve the tracking update rate of the system. The third phase is part of future work and is to have the software completely C++ driven with a graphics user interface. This software design enables the fine resolution tracking of the UWB two-cluster AOA tracking system.

  14. Attitude and position tracking

    CSIR Research Space (South Africa)

    Candy, LP

    2011-01-01

    Full Text Available Several applications require the tracking of attitude and position of a body based on velocity data. It is tempting to use direction cosine matrices (DCM), for example, to track attitude based on angular velocity data, and to integrate the linear...

  15. Eye-Tracking

    Directory of Open Access Journals (Sweden)

    Gabriela GROSSECK

    2006-01-01

    Full Text Available Eye-tracking: one of the newest and most efficient methods of improving on-line marketing communication is called eye-tracking. Marketers have borrowed this technique, usually used in psychological and medical research, in order to study web users with the help of a video camera incorporated in the monitor.

  16. Large scale tracking algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Love, Joshua Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Melgaard, David Kennett [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pitts, Todd Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zollweg, Joshua David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Dylan Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nandy, Prabal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Whitlow, Gary L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Byrne, Raymond Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  17. Why we are tracking

    DEFF Research Database (Denmark)

    Tække, Jesper

    2015-01-01

    In this short essay, concerning why we are tracking, I will try to frame tracking as an evolutionary developed skill that humans need to survive. From an evolutionary point zero life must reflect upon itself in regard to its surrounding world as a kind of societal self-synchronization in this reg......In this short essay, concerning why we are tracking, I will try to frame tracking as an evolutionary developed skill that humans need to survive. From an evolutionary point zero life must reflect upon itself in regard to its surrounding world as a kind of societal self......-synchronization in this regard (Spencer 1890, Luhmann 2000, Tække 2014, 2011). I was inspired by Jill Walker Rettberg’s book: “Seeing Ourselves through Technology” and her presentation at the seminar: “Tracking Culture” arranged by Anders Albrechtslund in Aarhus January 2015....

  18. A novel track imaging system as a range counter

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. [National Institute of Radiological Sciences (Japan); Matsufuji, N. [National Institute of Radiological Sciences (Japan); Tokyo Institute of Technology (Japan); Kanayama, S. [Chiba University (Japan); Ishida, A. [National Institute of Radiological Sciences (Japan); Tokyo Institute of Technology (Japan); Kohno, T. [Tokyo Institute of Technology (Japan); Koba, Y.; Sekiguchi, M.; Kitagawa, A.; Murakami, T. [National Institute of Radiological Sciences (Japan)

    2016-05-01

    An image-intensified, camera-based track imaging system has been developed to measure the tracks of ions in a scintillator block. To study the performance of the detector unit in the system, two types of scintillators, a dosimetrically tissue-equivalent plastic scintillator EJ-240 and a CsI(Tl) scintillator, were separately irradiated with carbon ion ({sup 12}C) beams of therapeutic energy from HIMAC at NIRS. The images of individual ion tracks in the scintillators were acquired by the newly developed track imaging system. The ranges reconstructed from the images are reported here. The range resolution of the measurements is 1.8 mm for 290 MeV/u carbon ions, which is considered a significant improvement on the energy resolution of the conventional ΔE/E method. The detector is compact and easy to handle, and it can fit inside treatment rooms for in-situ studies, as well as satisfy clinical quality assurance purposes.

  19. Abiotic degradation of plastic films

    Science.gov (United States)

    Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

    2017-01-01

    Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

  20. Plastics in the Marine Environment.

    Science.gov (United States)

    Law, Kara Lavender

    2017-01-03

    Plastics contamination in the marine environment was first reported nearly 50 years ago, less than two decades after the rise of commercial plastics production, when less than 50 million metric tons were produced per year. In 2014, global plastics production surpassed 300 million metric tons per year. Plastic debris has been detected worldwide in all major marine habitats, in sizes from microns to meters. In response, concerns about risks to marine wildlife upon exposure to the varied forms of plastic debris have increased, stimulating new research into the extent and consequences of plastics contamination in the marine environment. Here, I present a framework to evaluate the current understanding of the sources, distribution, fate, and impacts of marine plastics. Despite remaining knowledge gaps in mass budgeting and challenges in investigating ecological impacts, the increasing evidence of the ubiquity of plastics contamination in the marine environment, the continued rapid growth in plastics production, and the evidence-albeit limited-of demonstrated impacts to marine wildlife support immediate implementation of source-reducing measures to decrease the potential risks of plastics in the marine ecosystem.

  1. Persistent Aerial Tracking

    KAUST Repository

    Mueller, Matthias

    2016-04-13

    In this thesis, we propose a new aerial video dataset and benchmark for low altitude UAV target tracking, as well as, a photo-realistic UAV simulator that can be coupled with tracking methods. Our benchmark provides the rst evaluation of many state of-the-art and popular trackers on 123 new and fully annotated HD video sequences captured from a low-altitude aerial perspective. Among the compared trackers, we determine which ones are the most suitable for UAV tracking both in terms of tracking accuracy and run-time. We also present a simulator that can be used to evaluate tracking algorithms in real-time scenarios before they are deployed on a UAV "in the field", as well as, generate synthetic but photo-realistic tracking datasets with free ground truth annotations to easily extend existing real-world datasets. Both the benchmark and simulator will be made publicly available to the vision community to further research in the area of object tracking from UAVs. Additionally, we propose a persistent, robust and autonomous object tracking system for unmanned aerial vehicles (UAVs) called Persistent Aerial Tracking (PAT). A computer vision and control strategy is applied to a diverse set of moving objects (e.g. humans, animals, cars, boats, etc.) integrating multiple UAVs with a stabilized RGB camera. A novel strategy is employed to successfully track objects over a long period, by \\'handing over the camera\\' from one UAV to another. We integrate the complete system into an off-the-shelf UAV, and obtain promising results showing the robustness of our solution in real-world aerial scenarios.

  2. Use of recycled plastics in wood plastic composites - a review.

    Science.gov (United States)

    Kazemi Najafi, Saeed

    2013-09-01

    The use of recycled and waste thermoplastics has been recently considered for producing wood plastic composites (WPCs). They have great potential for WPCs manufacturing according to results of some limited researches. This paper presents a detailed review about some essential properties of waste and recycled plastics, important for WPCs production, and of research published on the effect of recycled plastics on the physical and mechanical properties of WPCs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Direct liquefaction of plastics and coprocessing of coal with plastics

    Energy Technology Data Exchange (ETDEWEB)

    Huffman, G.P.; Feng, Z.; Mahajan, V. [Univ. of Kentucky, Lexington, KY (United States)

    1995-12-31

    The objectives of this work were to optimize reaction conditions for the direct liquefaction of waste plastics and the coprocessing of coal with waste plastics. In previous work, the direct liquefaction of medium and high density polyethylene (PE), polypropylene (PPE), poly(ethylene terephthalate) (PET), and a mixed plastic waste, and the coliquefaction of these plastics with coals of three different ranks was studied. The results established that a solid acid catalyst (HZSM-5 zeolite) was highly active for the liquefaction of the plastics alone, typically giving oil yields of 80-95% and total conversions of 90-100% at temperatures of 430-450 {degrees}C. In the coliquefaction experiments, 50:50 mixtures of plastic and coal were used with a tetralin solvent (tetralin:solid = 3:2). Using approximately 1% of the HZSM-5 catalyst and a nanoscale iron catalyst, oil yields of 50-70% and total conversion of 80-90% were typical. In the current year, further investigations were conducted of the liquefaction of PE, PPE, and a commingled waste plastic obtained from the American Plastics Council (APC), and the coprocessing of PE, PPE and the APC plastic with Black Thunder subbituminous coal. Several different catalysts were used in these studies.

  4. Tree plastic bark

    OpenAIRE

    Casado Arroyo, Carlos

    2016-01-01

    “Tree plastic bark" consiste en la realización de una intervención artística en un entorno natural concreto, generando de esta manera un Site Specific(1). Como hace alusión Rosalind Krauss en sus reflexiones “La escultura en el campo expandido”(2), comenta que su origen esta claramente ligado con el concepto de monumentalidad. La escultura es un monumento, se crea para conmemorar algún hecho o personaje relevante y está realizada para una ubicación concreta. La investigación parte de la id...

  5. Study on cosmic ray iron isotopes in an emulsion-plastic detector

    International Nuclear Information System (INIS)

    Scherzer, R.; Enge, W.; Beaujean, R.; Hertzman, S.; Kristiansson, K.; Soederstroem, K.

    1976-01-01

    Combining cellulose nitrate plastics and nuclear emulsions a detector system for mass measurement in the iron group has been designed. The detector operates in an energy interval of 500-700 MeV/Nuc and has been flown in two balloon flights. In the emulsion range and track width are measured. Cone lengths and range are measured in the plastics. The charge of a particle can be determined both in emulsion and in plastics. The mass is determined by relating cone lengths to residual range. One advantage of this detector system is the high rejection of interacting particles. The present status is reported. (orig.) [de

  6. Plastic pollutants in water environment

    Directory of Open Access Journals (Sweden)

    Mrowiec Bożena

    2017-12-01

    Full Text Available Nowadays, wide applications of plastics result in plastic waste being present in the water environment in a wide variety of sizes. Plastic wastes are in water mainly as microplastics (the size range of 1 nm to < 5 mm. Microplastics have been recognized as an emerging threat, as well as ecotoxicological and ecological risk for water ecosystems. In this review are presented some of the physicochemical properties of plastic materials that determine their toxic effect on the aquatic environment. Wastewater treatment plants (WWTPs are mentioned as one of main sources of microplastics introduced into fresh water, and rivers are the pathways for the transportation of the pollutants to seas and oceans. But, effluents from tertiary wastewater treatment facilities can contain only minimally microplastic loads. The issue of discharge reduction of plastic pollutants into water environment needs activities in the scope of efficient wastewater treatment, waste disposal, recycling of plastic materials, education and public involvement.

  7. Scale adaptive compressive tracking.

    Science.gov (United States)

    Zhao, Pengpeng; Cui, Shaohui; Gao, Min; Fang, Dan

    2016-01-01

    Recently, the compressive tracking (CT) method (Zhang et al. in Proceedings of European conference on computer vision, pp 864-877, 2012) has attracted much attention due to its high efficiency, but it cannot well deal with the scale changing objects due to its constant tracking box. To address this issue, in this paper we propose a scale adaptive CT approach, which adaptively adjusts the scale of tracking box with the size variation of the objects. Our method significantly improves CT in three aspects: Firstly, the scale of tracking box is adaptively adjusted according to the size of the objects. Secondly, in the CT method, all the compressive features are supposed independent and equal contribution to the classifier. Actually, different compressive features have different confidence coefficients. In our proposed method, the confidence coefficients of features are computed and used to achieve different contribution to the classifier. Finally, in the CT method, the learning parameter λ is constant, which will result in large tracking drift on the occasion of object occlusion or large scale appearance variation. In our proposed method, a variable learning parameter λ is adopted, which can be adjusted according to the object appearance variation rate. Extensive experiments on the CVPR2013 tracking benchmark demonstrate the superior performance of the proposed method compared to state-of-the-art tracking algorithms.

  8. The influence of mechanical vibrations of railway and car traffics on the radon exhalation using track detector technique

    International Nuclear Information System (INIS)

    Moharram, B.M.

    2000-01-01

    The influence of train and car traffic vibrations on the radon concentration (CRn) increase near the railway tracks and the heavy traffic roads. It was estimated along the railway road, and perpendicular directions using CR-39 detectors. The special radius of the influence is about 32 m, while the related value for car traffics is found to be about 25 m. The base line of radon concentration in soil gas and radon exhalation are estimated in the whole area, far from the center of traffic roads by a distance (> 100 m) in different different directions and found to be 0.6 Bq/L and 1.25 x 10 4 Bq m -2 respectively.It is easy to detect that the average ratio between the radon concentration at its higher level and its base line, which is regular concentration of radon in the ordinary positions far from the effect of traffics, is about 1.18 for railway traffics. While the related value to vehicle traffic is about 1.23, which is higher than that of railway traffic because the ground is stimulated per minutely

  9. Plastic food packaging and health

    Directory of Open Access Journals (Sweden)

    Raika Durusoy

    2011-02-01

    Full Text Available Plastics have a wide usage in our daily lives. One of their uses is for food packaging and food containers. The aim of this review is to introduce different types of chemicals that can leach from food packaging plastics into foods and cause human exposure and to mention their effects on health. The types of plastics were reviewed under the 13 headings in Turkish Codex Alimentarius and plastics recycling symbols were provided to enable the recognition of the type of plastic when applicable. Chemicals used during the production and that can cause health risks are investigated under the heading of the relevant type of plastic. The most important chemicals from plastic food packaging that can cause toxicity are styrene, 1,3-butadiene, melamine, formaldehyde, acrylamide, di-2-ethylhexyl phthalate, di-2-ethylhexyl adipate, vinyl chloride and bisphenol A. These chemicals have endocrine disrupting, carcinogenic and/or development disrupting effects. These chemicals may leach into foods depending on the chemical properties of the plastic or food, temperature during packaging, processing and storage, exposure to UV and duration of storage. Contact with fatty/oily or acidic foods, heating of the food inside the container, or drinking hot drinks from plastic cups, use of old and scratched plastics and some detergents increase the risk of leaching. The use of plastic containers and packaging for food and beveradges should be avoided whenever possible and when necessary, less harmful types of plastic should be preferred. [TAF Prev Med Bull 2011; 10(1.000: 87-96

  10. Plastic neutron detectors.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Tiffany M.S; King, Michael J.; Doty, F. Patrick

    2008-12-01

    photoresponse with increasing stretch ratio. Other additives examined, including small molecules and cosolvents, did not cause any significant increase in photoresponse. Finally, we discovered an inverse-geometric particle track effect wherein increased track lengths created by tilting the detector off normal incidence resulted in decreased signal collection. This is interpreted as a trap-filling effect, leading to increased carrier mobility along the particle track direction. Estimated collection efficiency along the track direction was near 20 electrons/micron of track length, sufficient for particle counting in 50 micron thick films.

  11. Fast track-hoftealloplastik

    DEFF Research Database (Denmark)

    Hansen, Torben Bæk; Gromov, Kirill; Kristensen, Billy B

    2017-01-01

    Fast-track surgery implies a coordinated perioperative approach aimed at reducing surgical stress and facilitating post-operative recovery. The fast-track programme has reduced post-operative length of stay and has led to shorter convalescence with more rapid functional recovery and decreased...... morbidity and mortality in total hip arthroplasty. It should now be a standard total hip arthroplasty patient pathway, but fine tuning of the multiple factors in the fast-track pathway is still needed in patients with special needs or high comorbidity burden....

  12. Solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Medeiros, J.A.; Carvalho, M.L.C.P. de

    1992-12-01

    Solid state nuclear track detectors (SSNTD) are dielectric materials, crystalline or vitreous, which registers tracks of charged nuclear particles, like alpha particles or fission fragments. Chemical etching of the detectors origin tracks that are visible at the optical microscope: track etching rate is higher along the latent track, where damage due to the charged particle increase the chemical potential, and etching rate giving rise to holes, the etched tracks. Fundamental principles are presented as well as some ideas of main applications. (author)

  13. Clinical disorders of brain plasticity.

    Science.gov (United States)

    Johnston, Michael V

    2004-03-01

    Clinical disorders of brain plasticity are common in the practice of child neurology. Children have an enhanced capacity for brain plasticity compared to adults as demonstrated by their superior ability to learn a second language or their capacity to recover from brain injuries or radical surgery such as hemispherectomy for epilepsy. Basic mechanisms that support plasticity during development include persistence of neurogenesis in some parts of the brain, elimination of neurons through apoptosis or programmed cell death, postnatal proliferation and pruning of synapses, and activity-dependent refinement of neuronal connections. Brain plasticity in children can be divided into four types: adaptive plasticity that enhances skill development or recovery from brain injury; impaired plasticity associated with cognitive impairment; excessive plasticity leading to maladaptive brain circuits; and plasticity that becomes the brain's 'Achilles' Heel' because makes it vulnerable to injury. A broad group of pediatric neurologic disorders can be understood in terms of their impact on fundamental mechanisms for brain plasticity. These include neurofibromatosis, tuberous sclerosis, Fragile X syndrome, other inherited forms of mental retardation, cretinism, Coffin-Lowry syndrome, lead poisoning, Rett syndrome, epilepsy, hypoxic-ischemic encephalopathy and cerebral palsy.

  14. Americium behaviour in plastic vessels

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  15. Americium behaviour in plastic vessels

    International Nuclear Information System (INIS)

    Legarda, F.; Herranz, M.; Idoeta, R.; Abelairas, A.

    2010-01-01

    The adsorption of 241 Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of 241 Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of 241 Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  16. Medical Student Mentorship in Plastic Surgery: The Mentee's Perspective.

    Science.gov (United States)

    Barker, Jenny C; Rendon, Juan; Janis, Jeffrey E

    2016-06-01

    Mentorship is a universal concept that has a significant impact on nearly every surgical career. Although frequently editorialized, true data investigating the value of mentorship are lacking in the plastic surgery literature. This study evaluates mentorship in plastic surgery from the medical student perspective. An electronic survey was sent to recently matched postgraduate year-1 integrated track residents in 2014, with a response rate of 76 percent. Seventy-seven percent of students reported a mentoring relationship. Details of the mentoring relationship were defined. Over 80 percent of students reported a mentor's influence in their decision to pursue plastic surgery, and nearly 40 percent of students expressed interest in practicing the same subspecialty as their mentor. Benefits of the relationship were also described. Mentees value guidance around career preparation and advice and prioritized "a genuine interest in their career and personal development" above all other mentor qualities (p ≤ 1.6 × 10). Mentees prefer frequent, one-on-one interactions over less frequent interaction or group activities. Students did not prefer "assigned" relationships (91 percent), but did prefer "facilitated exposure." Major barriers to mentorship included mentor time constraints and lack of exposure to plastic surgery. Indeed, significant differences in the presence of a mentoring relationship correlated with involvement of the plastic surgery department in the medical school curriculum. This study defines successes and highlights areas for improvement of mentorship of plastic surgery medical students. Successful mentorship may contribute to the future of plastic surgery, and a commitment toward this endeavor is needed at the local, departmental, and national leadership levels.

  17. New polyvinylchloride plasticizers

    Directory of Open Access Journals (Sweden)

    MAZITOVA Aliya Karamovna

    2017-11-01

    Full Text Available One of the main large-capacity polymers of modern chemical industry is polyvinylchloride (PVC. Polyvinylchloride is characterized by many useful engineering properties – chemical firmness in different environments, good electric properties, etc. It explains immensely various use of materials on the basis of PVC in different engineering industries. It is cable, building, light industries, mechanical engineering and automotive industry where PVC is widely applied. One of the reasons why PVC production is dramatically growing is that there is no yet other polymer which could be subjected to such various modifying as it is done with PVC. However under normal temperature this polymer is fragile and isn't elastic that limits the field of its application. Rapid growth of production of polyvinylchloride is explained by its ability to modify properties, due to introduction of special additives when processing. Introduction of plasticizers – mostlly esters of organic and inorganic acids – into PVC allows significant changing properties of polymer. Plasticizers facilitate process of receiving polymeric composition, increase flexibility and elasticity of the final polymeric product due to internal modification of polymeric molecule.

  18. Agency Correspondence Tracking System (ACTS)

    Data.gov (United States)

    US Agency for International Development — Agency Correspondence Tracking System: is an executive correspondence tracking system for the Administrator. It collects and organizes information on reports...

  19. Radon progeny deposition in track-detection diffusion chambers

    CERN Document Server

    Pressyanov, D; Simeonov, G

    1999-01-01

    The sensitivity dependence for cylindrical diffusion chambers that are used for radon track-detection measurements on the deposition fraction of radon progeny atoms has been theoretically studied (sensitivity is the ratio: area track density/integrated sup 2 sup 2 sup 2 Rn activity concentration). Experimentally, the sensitivity values of both the metal- and plastic-made chambers were determined. Results indicate that the experimental sensitivity for metal chambers is in accordance with the theoretical model while a deviation of 15% is observed for plastic chambers. The uncertainty in the sensitivity values that is related to possible variations of the diffusion coefficient for sup 2 sup 1 sup 8 Po atoms was estimated to be less than 10%. (author)

  20. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  1. Energy Tracking Software Platform

    Energy Technology Data Exchange (ETDEWEB)

    Ryan Davis; Nathan Bird; Rebecca Birx; Hal Knowles

    2011-04-04

    Acceleration has created an interactive energy tracking and visualization platform that supports decreasing electric, water, and gas usage. Homeowners have access to tools that allow them to gauge their use and track progress toward a smaller energy footprint. Real estate agents have access to consumption data, allowing for sharing a comparison with potential home buyers. Home builders have the opportunity to compare their neighborhood's energy efficiency with competitors. Home energy raters have a tool for gauging the progress of their clients after efficiency changes. And, social groups are able to help encourage members to reduce their energy bills and help their environment. EnergyIT.com is the business umbrella for all energy tracking solutions and is designed to provide information about our energy tracking software and promote sales. CompareAndConserve.com (Gainesville-Green.com) helps homeowners conserve energy through education and competition. ToolsForTenants.com helps renters factor energy usage into their housing decisions.

  2. LHCb on track

    CERN Document Server

    2006-01-01

    On 7 and 8 June 2006, the last large component of the LHCb experiment was lowered into the cavern. This 10-tonne, 18-metre long metal structure known as 'the bridge' will support the LHCb tracking system.

  3. LHCb VELO Tracking Resolutions

    CERN Multimedia

    Alexander, Michael

    2011-01-01

    The excellent tracking performance of the Vertex Locator (VELO) at LHCb is presented. The resolutions it achieves on single hits, impact parameters, and primary vertex positions are shown, with particular attention paid to measurement of impact parameters.

  4. Track Loading Vehicle - TLV

    Data.gov (United States)

    Federal Laboratory Consortium — The TLV is designed to apply forces close to the strength limits of the rails and other track structure components, such as ties, rail fasteners, and ballast, while...

  5. Matter Tracking Information System -

    Data.gov (United States)

    Department of Transportation — The Matter Tracking Information System (MTIS) principle function is to streamline and integrate the workload and work activity generated or addressed by our 300 plus...

  6. Case Analysis Tracking System

    Data.gov (United States)

    National Archives and Records Administration — CATS tracks Public and Federal Agency Reference Requests for OPF (Official Personnel Folder) , EMF (Employee Medical Folder), and eOPF (electronic Official Personnel...

  7. MARS PATHFINDER RADIO TRACKING

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Pathfinder (MPF) Radio Science (RS) data archive contains both raw radio tracking data collected during the surface lifetime of the MPF Lander and results...

  8. Financial Disclosure Tracking System

    Data.gov (United States)

    US Agency for International Development — USAID's FDTS identifies personal service contractors and local employees who should file disclosure reports. It tracks late filers and identifies those who must take...

  9. Human Capital Tracking Tool -

    Data.gov (United States)

    Department of Transportation — AVS is now required to collect, track, and report on data from the following Flight, Business and Workforce Plan. The Human Resource Management’s Performance Target...

  10. Procurement Tracking System (PTS)

    Data.gov (United States)

    Office of Personnel Management — The Procurement Tracking System (PTS) is used solely by the procurement staff of the Office of the Inspector General (OIG) at the U.S. Office of Personnel Management...

  11. Jet Car Track Site

    Data.gov (United States)

    Federal Laboratory Consortium — Located in Lakehurst, New Jersey, the Jet Car Track Site supports jet cars with J57 engines and has a maximum jet car thrust of 42,000 pounds with a maximum speed of...

  12. The 'Goldilocks' effect: preservation bias in vertebrate track assemblages.

    Science.gov (United States)

    Falkingham, P L; Bates, K T; Margetts, L; Manning, P L

    2011-08-07

    Finite-element analysis was used to investigate the extent of bias in the ichnological fossil record attributable to body mass. Virtual tracks were simulated for four dinosaur taxa of different sizes (Struthiomimus, Tyrannosaurus, Brachiosaurus and Edmontosaurus), in a range of substrate conditions. Outlines of autopodia were generated based upon osteology and published soft-tissue reconstructions. Loads were applied vertically to the feet equivalent to the weight of the animal, and distributed accordingly to fore- and hindlimbs where relevant. Ideal, semi-infinite elastic-plastic substrates displayed a 'Goldilocks' quality where only a narrow range of loads could produce tracks, given that small animals failed to indent the substrate, and larger animals would be unable to traverse the area without becoming mired. If a firm subsurface layer is assumed, a more complete assemblage is possible, though there is a strong bias towards larger, heavier animals. The depths of fossil tracks within an assemblage may indicate thicknesses of mechanically distinct substrate layers at the time of track formation, even when the lithified strata appear compositionally homogeneous. This work increases the effectiveness of using vertebrate tracks as palaeoenvironmental indicators in terms of inferring substrate conditions at the time of track formation. Additionally, simulated undertracks are examined, and it is shown that complex deformation beneath the foot may not be indicative of limb kinematics as has been previously interpreted, but instead ridges and undulations at the base of a track may be a function of sediment displacement vectors and pedal morphology.

  13. Function integrated track system

    OpenAIRE

    Hohnecker, Eberhard

    2010-01-01

    The paper discusses a function integrated track system that focuses on the reduction of acoustic emissions from railway lines. It is shown that the combination of an embedded rail system (ERS), a sound absorbing track surface, and an integrated mini sound barrier has significant acoustic advantages compared to a standard ballast superstructure. The acoustic advantages of an embedded rail system are particularly pronounced in the case of railway bridges. Finally, it is shown that a...

  14. Plastics recycling: challenges and opportunities.

    Science.gov (United States)

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-07-27

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  15. Plastics recycling: challenges and opportunities

    Science.gov (United States)

    Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

    2009-01-01

    Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it

  16. Public perception of Plastic Surgery.

    Science.gov (United States)

    de Blacam, Catherine; Kilmartin, Darren; Mc Dermott, Clodagh; Kelly, Jack

    2015-02-01

    Public perception of Plastic Surgery is strongly influenced by the media and may not reflect the broad scope of work within the speciality. The aim of this study was to provide an assessment of the general public's perception of plastic surgical practice and to report the perceived importance of Plastic Surgery relative to other specialities working within a large tertiary referral centre. 899 members of the public who attended our Emergency Department completed a questionnaire where they matched eight surgical specialities with 30 operative procedures and ranked the importance of 30 different hospital specialities using a Likert scale. The majority of respondents correctly identified plastic surgeons as performing each of the cosmetic procedures listed (abdominoplasty 63.7%; breast augmentation 59.1%; facelift 61.35%; liposuction 59.7%). Plastic Surgery was identified as the primary speciality involved in breast reconstruction (49.3%) and burns surgery (43.0%). There was poor understanding of the role of plastic surgeons in hand surgery, with only 4.7% of respondents attributing tendon repair to plastic surgeons. Plastic Surgery ranked lowest of 30 specialities in terms of importance in providing care for patients within the hospital. Plastic Surgery is often misunderstood within the wider community and misconceptions reflect the influence of the media in highlighting certain aspects of the speciality. It behoves our professional organisations to highlight the importance of Plastic and Reconstructive Surgery within major tertiary referral centres. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Nano-Ceramic Coated Plastics

    Science.gov (United States)

    Cho, Junghyun

    2013-01-01

    Plastic products, due to their durability, safety, and low manufacturing cost, are now rapidly replacing cookware items traditionally made of glass and ceramics. Despite this trend, some still prefer relatively expensive and more fragile ceramic/glassware because plastics can deteriorate over time after exposure to foods, which can generate odors, bad appearance, and/or color change. Nano-ceramic coatings can eliminate these drawbacks while still retaining the advantages of the plastic, since the coating only alters the surface of the plastic. The surface coating adds functionality to the plastics such as self-cleaning and disinfectant capabilities that result from a photocatalytic effect of certain ceramic systems. These ceramic coatings can also provide non-stick surfaces and higher temperature capabilities for the base plastics without resorting to ceramic or glass materials. Titanium dioxide (TiO2) and zinc oxide (ZnO) are the candidates for a nano-ceramic coating to deposit on the plastics or plastic films used in cookware and kitchenware. Both are wide-bandgap semiconductors (3.0 to 3.2 eV for TiO2 and 3.2 to 3.3 eV for ZnO), so they exhibit a photocatalytic property under ultraviolet (UV) light. This will lead to decomposition of organic compounds. Decomposed products can be easily washed off by water, so the use of detergents will be minimal. High-crystalline film with large surface area for the reaction is essential to guarantee good photocatalytic performance of these oxides. Low-temperature processing (plastics. One possible way of processing nanoceramic coatings at low temperatures (plastic materials (silicone, Teflon, PET, etc.) that can possess both photocatalytic oxide properties and flexible plastic properties. Processing cost is low and it does not require any expensive equipment investment. Processing can be scalable to current manufacturing infrastructure.

  18. Sustainable reverse logistics for household plastic waste

    NARCIS (Netherlands)

    Bing, X.

    2014-01-01

    Summary of the thesis titled “Sustainable Reverse Logistics for Household Plastic Waste”

    PhD Candidate: Xiaoyun Bing

    Recycled plastic can be used in the manufacturing of plastic products to reduce the use of virgin plastics material. The cost of recycled plastics is usually lower

  19. Sustainable reverse logistics for household plastic waste

    NARCIS (Netherlands)

    Bing, X.

    2014-01-01

    Summary of the thesis titled “Sustainable Reverse Logistics for Household Plastic Waste” PhD Candidate: Xiaoyun Bing Recycled plastic can be used in the manufacturing of plastic products to reduce the use of virgin plastics material. The cost of recycled plastics is usually lower than

  20. Material Tracking Using LANMAS

    International Nuclear Information System (INIS)

    Armstrong, F.

    2010-01-01

    LANMAS is a transaction-based nuclear material accountability software product developed to replace outdated and legacy accountability systems throughout the DOE. The core underlying purpose of LANMAS is to track nuclear materials inventory and report transactions (movement, mixing, splitting, decay, etc.) to the Nuclear Materials Management and Safeguards System (NMMSS). While LANMAS performs those functions well, there are many additional functions provided by the software product. As a material is received onto a site or created at a site, its entire lifecycle can be tracked in LANMAS complete to its termination of safeguards. There are separate functions to track material movements between and within material balance areas (MBAs). The level of detail for movements within a MBA is configurable by each site and can be as high as a site designation or as detailed as building/room/rack/row/position. Functionality exists to track the processing of materials, either as individual items or by modeling a bulk process as an individual item to track inputs and outputs from the process. In cases where sites have specialized needs, the system is designed to be flexible so that site specific functionality can be integrated into the product. This paper will demonstrate how the software can be used to input material into an account and track it to its termination of safeguards.

  1. Nuclear tracks in solids

    International Nuclear Information System (INIS)

    Espinosa G, G.

    1994-01-01

    The main purpose of this book is to dispose within reach of young professionals in the fields of Physics, Biology, Chemistry, Medicine, Geology, Earth Sciences and Ecology between others, the basis of the Solid State Nuclear Track Methodology (SSNTM). The contents of this book is distributed as follows: Chapter 1, occurs the basic aspects on the formation of tracks in solid state materials. Chapter 2 analyzes the formation of the solid state nuclear tracks in order to three fundamental steps in the process: ionizing radiation, chemical revealed of the track and characterization and reading of the tracks. In the chapter 3, was made an analysis of the possible materials like detecting for tracks, describing the experimental process for the parameters optimization and they are also specified the characteristics of the instrumentation developed for the STD. In the chapter 4, the results obtained in applications are shown specify of the STD, where it was made emphasis in the evaluation of radon within the city and the determination of profiles and pollutants of transuranic radioactive materials. In the chapter 5, it was made an analysis of the applications of the STD as well as their future perspectives in the fields of the science and the technology. Finally, in the conclusions summary the excellent aspects of each one of the chapters and the general results are presented. (Author)

  2. Cellular plasticity during vertebrate appendage regeneration.

    Science.gov (United States)

    Monaghan, James R; Maden, Malcolm

    2013-01-01

    Many vertebrates have the amazing ability to regenerate all or portions of appendages including limbs, tails, fins, and digits. Unfortunately, our understanding of the cellular and molecular basis of appendage regeneration is severely lacking. However, recent technological advances that facilitate the tracking of cell lineages in vivo through space and time are allowing us to address the unknowns of regeneration, such as characterizing the cells that contribute to regeneration and identifying the tissues these cells differentiate into during regeneration. Here, we describe the experiments and the surprisingly uniform results that have emerged across diverse vertebrate species when specific cell lineages have been tracked during vertebrate appendage regeneration. These investigations show that vertebrates, from zebrafish to salamanders to mammals, utilize a limited amount of cellular plasticity to regenerate missing appendages. The universal approach to appendage regeneration is not to generate pluripotent cells that then differentiate into the new organ, but instead to generate lineage-restricted cells that are propagated in a progenitor-like state. Lessons learned from these natural cases of complex tissue regeneration might inform regenerative medicine on the best approach for re-growing complex tissues.

  3. Large angle tracking and high discriminating tracking in nuclear emulsion

    International Nuclear Information System (INIS)

    Matsuo, Tomokazu; Shibuya, Hiroshi; Ogawa, Satoru; Fukuda, Tsutomu; Mikado, Shoji

    2015-01-01

    Nuclear emulsion is a high resolution and re-analyzable detector. Conventional “Track Selector” which have angle acceptance |tan θ|<0.6 are widely used to find tracks in emulsion. We made a new track selector “Fine Track Selector” (FTS) which has large angle acceptance and high discriminating ability. The FTS reduces fake tracks using new algorithms, navigation etc. FTS also keeps finding efficiency of tracks around 90% in an angle range of |tan θ| < 3.5. FTS was applied to the τ candidate in OPERA and no additional tracks found. FTS will be useful to our new J-PARC emulsion experiment.

  4. Architecture of European Plastic Surgery

    NARCIS (Netherlands)

    Nicolai, J. -P. A.; Banic, A.; Molea, G.; Mazzola, R.; Poell, J. G.

    2006-01-01

    The architecture of European Plastic Surgery was published in 1996 [Nicolai JPA, Scuderi N. Plastic surgical Europe in an organogram. Eur J Plast Surg 1996; 19: 253-6.] It is the objective of this paper to update information of that article. Continuing medical education (CME), science, training,

  5. Nigerian Journal of Plastic Surgery

    African Journals Online (AJOL)

    The Nigerian Journal of Plastic Surgery has its objectives in publishing original articles about developments in all areas related to plastic and reconstructive surgery as well as to trauma surgery. It also serves as a means of providing a forum for correspondence, information and discussion. It also accepts review articles that ...

  6. Plastic Deformation of Metal Surfaces

    DEFF Research Database (Denmark)

    Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu

    2013-01-01

    Plastic deformation of metal surfaces by sliding and abrasion between moving parts can be detrimental. However, when the plastic deformation is controlled for example by applying different peening techniques hard surfaces can be produced which can increase the fracture resistance and fatigue life...

  7. Plastics to fuel: A review

    Science.gov (United States)

    This paper reviews recent developments in catalytic and non-catalytic degradation of waste plastics into fuels. Thermal degradation decomposes plastic into three fractions: gas, crude oil, and solid residue. Crude oil from non-catalytic pyrolysis is usually composed of higher boiling point hydrocarb...

  8. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  9. Neural plasticity across the lifespan.

    Science.gov (United States)

    Power, Jonathan D; Schlaggar, Bradley L

    2017-01-01

    An essential feature of the brain is its capacity to change. Neuroscientists use the term 'plasticity' to describe the malleability of neuronal connectivity and circuitry. How does plasticity work? A review of current data suggests that plasticity encompasses many distinct phenomena, some of which operate across most or all of the lifespan, and others that operate exclusively in early development. This essay surveys some of the key concepts related to neural plasticity, beginning with how current patterns of neural activity (e.g., as you read this essay) come to impact future patterns of activity (e.g., your memory of this essay), and then extending this framework backward into more development-specific mechanisms of plasticity. WIREs Dev Biol 2017, 6:e216. doi: 10.1002/wdev.216 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

  10. Phenotypic Plasticity and Species Coexistence.

    Science.gov (United States)

    Turcotte, Martin M; Levine, Jonathan M

    2016-10-01

    Ecologists are increasingly interested in predicting how intraspecific variation and changing trait values impact species interactions and community composition. For many traits, much of this variation is caused by phenotypic plasticity, and thus the impact of plasticity on species coexistence deserves robust quantification. Partly due to a lack of sound theoretical expectations, empirical studies make contradictory claims regarding plasticity effects on coexistence. Our critical review of this literature, framed in modern coexistence theory, reveals that plasticity affects species interactions in ways that could impact stabilizing niche differences and competitive asymmetries. However, almost no study integrates these measures to quantify the net effect of plasticity on species coexistence. To address this challenge, we outline novel empirical approaches grounded in modern theory. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Biodegradability of degradable plastic waste.

    Science.gov (United States)

    Agamuthu, P; Faizura, Putri Nadzrul

    2005-04-01

    Plastic waste constitutes the third largest waste volume in Malaysian municipal solid waste (MSW), next to putrescible waste and paper. The plastic component in MSW from Kuala Lumpur averages 24% (by weight), whereas the national mean is about 15%. The 144 waste dumps in the country receive about 95% of the MSW, including plastic waste. The useful life of the landfills is fast diminishing as the plastic waste stays un-degraded for more than 50 years. In this study the compostability of polyethylene and pro-oxidant additive-based environmentally degradable plastics (EDP) was investigated. Linear low-density polyethylene (LLDPE) samples exposed hydrolytically or oxidatively at 60 degrees C showed that the abiotic degradation path was oxidative rather than hydrolytic. There was a weight loss of 8% and the plastic has been oxidized as shown by the additional carbonyl group exhibited in the Fourier transform infra red (FTIR) Spectrum. Oxidation rate seemed to be influenced by the amount of pro-oxidant additive, the chemical structure and morphology of the plastic samples, and the surface area. Composting studies during a 45-day experiment showed that the percentage elongation (reduction) was 20% for McD samples [high-density polyethylene, (HDPE) with 3% additive] and LL samples (LLDPE with 7% additive) and 18% reduction for totally degradable plastic (TDP) samples (HDPE with 3% additive). Lastly, microbial experiments using Pseudomonas aeroginosa on carbon-free media with degradable plastic samples as the sole carbon source, showed confirmatory results. A positive bacterial growth and a weight loss of 2.2% for degraded polyethylene samples were evident to show that the degradable plastic is biodegradable.

  12. Plasticity and beyond microstructures, crystal-plasticity and phase transitions

    CERN Document Server

    Hackl, Klaus

    2014-01-01

    The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

  13. Operational specifications of the L.I.T.E.S. (Laser Illuminated Track Etch Scattering) dosemeter reader

    International Nuclear Information System (INIS)

    Moore, M.E.; Devine, R.T.; Gepford, H.J.; McKeever, R.J.; Hoffman, J.M.

    2004-01-01

    The Personnel Dosimetry Operations Team at the Los Alamos National Laboratory (LANL) has accepted the LITES dosimeter reader into its suite of radiation dose measurement instruments. The LITES instrument transmits coherent light from a HeNe laser through the pertinent track etch foil and a photodiode measures the amount of light scattered by the etched tracks. A small beam stop blocks the main laser light, while a lens refocuses the scattered light into the photodiode. Three stepper motors in the current LITES system are used to position a carousel that holds 36 track etch dosimeters. Preliminary work with the LITES system demonstrated the device had a linear response in counting foils subjected to exposures up to 50 mSv (5.0 rem). The United States Department of Energy requires that annual general employee dose not exceed 50 mSv (5.0 rem). On a regular basis, LANL uses the Autoscan 60 reader system (Thermo Electron Corp.) for counting track etch dosimeters. However, LANL uses a 15 hour etch process for CR39 dosimeters, and this produces more and larger track etch pits than the 6 hour etch used by many institutions. Therefore, LANL only uses the Autoscan 60 for measuring neutron dose equivalent up to exposure levels of about 3 mSv (300 mrem). The LITES system has a measured lower limit of detection (LLD) of about 0.6 mSv (60 mrem), and it has a correlation coefficient of R 2 = 0.99 over an exposure range up to 500 mSv (50.0 rem). A series of blind studies were done using three methods: the Autoscan 60 system, manual counting by optical microscope, and the LITES instrument. A collection of track etch dosimeters of unknown NDE (neutron dose equivalent) were analyzed using the three methods, and the (PC) performance coefficient was calculated when the NDE became known. The Autoscan 60 and optical microscope methods had a combined PC = 0.171, and the LITES instrument had a PC = 0.194, where a PC less than or equal to 0.300 is considered satisfactory.

  14. Clean tracks for ATLAS

    CERN Multimedia

    2006-01-01

    First cosmic ray tracks in the integrated ATLAS barrel SCT and TRT tracking detectors. A snap-shot of a cosmic ray event seen in the different layers of both the SCT and TRT detectors. The ATLAS Inner Detector Integration Team celebrated a major success recently, when clean tracks of cosmic rays were detected in the completed semiconductor tracker (SCT) and transition radiation tracker (TRT) barrels. These tracking tests come just months after the successful insertion of the SCT into the TRT (See Bulletin 09/2006). The cosmic ray test is important for the experiment because, after 15 years of hard work, it is the last test performed on the fully assembled barrel before lowering it into the ATLAS cavern. The two trackers work together to provide millions of channels so that particles' tracks can be identified and measured with great accuracy. According to the team, the preliminary results were very encouraging. After first checks of noise levels in the final detectors, a critical goal was to study their re...

  15. Determination of boron distribution in a tumor induced in a rat brain

    International Nuclear Information System (INIS)

    Pazirandeh, Ali; Zargar, Maysam; Jameii, Behnam

    2006-01-01

    The success of BNCT is partly depends on the uniformity of boron carrier distribution in tumor. Rat model implanted with C6, 9L and F98 glioma cells has been widely utilized for the assessment of new therapeutic modalities. An experiment is undergoing on a rat brain to measure the boron distribution in tumor and rat brain at times after injection of glioma cells. After growth of tumor in rat brain, the BSH will be injected into the rat body. Then the rat is sacrificed and the brain is dissected. The frozen brain slices sandwiched with two pieces of CR-39 are bombarded with thermal neutrons. The alpha tracks registered on CR-39 after etching the plastic in NaOH are viewed on an optical microscopy equipped with a CCD. The boron distribution is assessed by scanning alpha tracks. (author)

  16. International policies to reduce plastic marine pollution from single-use plastics (plastic bags and microbeads): A review.

    Science.gov (United States)

    Xanthos, Dirk; Walker, Tony R

    2017-05-15

    Marine plastic pollution has been a growing concern for decades. Single-use plastics (plastic bags and microbeads) are a significant source of this pollution. Although research outlining environmental, social, and economic impacts of marine plastic pollution is growing, few studies have examined policy and legislative tools to reduce plastic pollution, particularly single-use plastics (plastic bags and microbeads). This paper reviews current international market-based strategies and policies to reduce plastic bags and microbeads. While policies to reduce microbeads began in 2014, interventions for plastic bags began much earlier in 1991. However, few studies have documented or measured the effectiveness of these reduction strategies. Recommendations to further reduce single-use plastic marine pollution include: (i) research to evaluate effectiveness of bans and levies to ensure policies are having positive impacts on marine environments; and (ii) education and outreach to reduce consumption of plastic bags and microbeads at source. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Space Plastic Recycling System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Techshot's proposed Space Plastic Recycler (SPR) is an automated closed loop plastic recycling system that allows the automated conversion of disposable ISS...

  18. Plastics and microplastics in the oceans: From emerging pollutants to emerged threat.

    Science.gov (United States)

    Avio, Carlo Giacomo; Gorbi, Stefania; Regoli, Francesco

    2017-07-01

    Plastic production has increased dramatically worldwide over the last 60 years and it is nowadays recognized as a serious threat to the marine environment. Plastic pollution is ubiquitous, but quantitative estimates on the global abundance and weight of floating plastics are still limited, particularly for the Southern Hemisphere and the more remote regions. Some large-scale convergence zones of plastic debris have been identified, but there is the urgency to standardize common methodologies to measure and quantify plastics in seawater and sediments. Investigations on temporal trends, geographical distribution and global cycle of plastics have management implications when defining the origin, possible drifting tracks and ecological consequences of such pollution. An elevated number of marine species is known to be affected by plastic contamination, and a more integrated ecological risk assessment of these materials has become a research priority. Beside entanglement and ingestion of macro debris by large vertebrates, microplastics are accumulated by planktonic and invertebrate organisms, being transferred along food chains. Negative consequences include loss of nutritional value of diet, physical damages, exposure to pathogens and transport of alien species. In addition, plastics contain chemical additives and efficiently adsorb several environmental contaminants, thus representing a potential source of exposure to such compounds after ingestion. Complex ecotoxicological effects are increasingly reported, but the fate and impact of microplastics in the marine environment are still far to be fully clarified. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Plastic debris in Mediterranean seabirds.

    Science.gov (United States)

    Codina-García, Marina; Militão, Teresa; Moreno, Javier; González-Solís, Jacob

    2013-12-15

    Plastic debris is often ingested by marine predators and can cause health disorders and even death. We present the first assessment of plastic ingestion in Mediterranean seabirds. We quantified and measured plastics accumulated in the stomach of 171 birds from 9 species accidentally caught by longliners in the western Mediterranean from 2003 to 2010. Cory's shearwaters (Calonectris diomedea) showed the highest occurrence (94%) and large numbers of small plastic particles per affected bird (on average N = 15.3 ± 24.4 plastics and mass = 23.4 ± 49.6 mg), followed by Yelkouan shearwaters (Puffinus yelkouan, 70%, N = 7.0 ± 7.9, 42.1 ± 100.0 mg), Balearic shearwaters (Puffinus mauretanicus, 70%, N = 3.6 ± 2.9, 5.5 ± 9.7 mg) and the rest of species (below 33%, N = 2.7, 113.6 ± 128.4 mg). Plastic characteristics did not differ between sexes and were not related to the physical condition of the birds. Our results point out the three endemic and threatened shearwater species as being particularly exposed to plastic accumulation.

  20. Water Vapor Permeation in Plastics

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Paul E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-01-01

    Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.

  1. Deep 6-DOF Tracking.

    Science.gov (United States)

    Garon, Mathieu; Lalonde, Jean-Francois

    2017-11-01

    We present a temporal 6-DOF tracking method which leverages deep learning to achieve state-of-the-art performance on challenging datasets of real world capture. Our method is both more accurate and more robust to occlusions than the existing best performing approaches while maintaining real-time performance. To assess its efficacy, we evaluate our approach on several challenging RGBD sequences of real objects in a variety of conditions. Notably, we systematically evaluate robustness to occlusions through a series of sequences where the object to be tracked is increasingly occluded. Finally, our approach is purely data-driven and does not require any hand-designed features: robust tracking is automatically learned from data.

  2. EYE GAZE TRACKING

    DEFF Research Database (Denmark)

    2017-01-01

    This invention relates to a method of performing eye gaze tracking of at least one eye of a user, by determining the position of the center of the eye, said method comprising the steps of: detecting the position of at least three reflections on said eye, transforming said positions to spanning...... a normalized coordinate system spanning a frame of reference, wherein said transformation is performed based on a bilinear transformation or a non linear transformation e.g. a möbius transformation or a homographic transformation, detecting the position of said center of the eye relative to the position...... of said reflections and transforming this position to said normalized coordinate system, tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system. Thereby calibration of a camera, such as knowledge of the exact position and zoom level of the camera, is avoided...

  3. Negotiating Family Tracking

    DEFF Research Database (Denmark)

    Albrechtslund, Anders; Bøge, Ask Risom; Sonne Damkjær, Maja

    This presentation explores the question: What motivates the use of tracking technologies in families, and how does the use transform the relations between parent and child? The purpose is to investigate why tracking technologies are used in families and how these technologies potentially change...... the relation between parents and children. The use of tracking technologies in families implicate negotiations about the boundaries of trust and intimacy in parent-child relations which can lead to strategies of resistance or modification (Fotel and Thomsen, 2004; Rooney, 2010; Steeves and Jones, 2010......). In the presentation, we report from a qualitative study that focuses on intergenerational relations. The study draws on empirical data from workshops with Danish families as well as individual and group interviews. We aim to gain insights about the sharing habits and negotiations in intimate family relations...

  4. Durability of wood plastic composites manufactured from recycled plastic

    Directory of Open Access Journals (Sweden)

    Irina Turku

    2018-03-01

    Full Text Available The influence of accelerated weathering, xenon-arc light and freeze-thaw cycling on wood plastic composites extruded from a recycled plastic was studied. The results showed that, in general, weathering had a stronger impact on samples made from plastic waste compared to a sample made from virgin material. After weathering, the mechanical properties, tensile and flexural, were reduced by 2–30%, depending on the plastic source. Wettability of the samples was shown to play a significant role in their stability. Chemical analysis with infrared spectroscopy and surface observation with a scan electron microscope confirmed the mechanical test results. Incorporation of carbon black retained the properties during weathering, reducing the wettability of the sample, diminishing the change of mechanical properties, and improving color stability. Keywords: Environmental science, Mechanical engineering, Materials science

  5. Durability of wood plastic composites manufactured from recycled plastic.

    Science.gov (United States)

    Turku, Irina; Kärki, Timo; Puurtinen, Ari

    2018-03-01

    The influence of accelerated weathering, xenon-arc light and freeze-thaw cycling on wood plastic composites extruded from a recycled plastic was studied. The results showed that, in general, weathering had a stronger impact on samples made from plastic waste compared to a sample made from virgin material. After weathering, the mechanical properties, tensile and flexural, were reduced by 2-30%, depending on the plastic source. Wettability of the samples was shown to play a significant role in their stability. Chemical analysis with infrared spectroscopy and surface observation with a scan electron microscope confirmed the mechanical test results. Incorporation of carbon black retained the properties during weathering, reducing the wettability of the sample, diminishing the change of mechanical properties, and improving color stability.

  6. Phenotypic plasticity, costs of phenotypes, and costs of plasticity

    DEFF Research Database (Denmark)

    Callahan, Hilary S; Maughan, Heather; Steiner, Uli

    2008-01-01

    Why are some traits constitutive and others inducible? The term costs often appears in work addressing this issue but may be ambiguously defined. This review distinguishes two conceptually distinct types of costs: phenotypic costs and plasticity costs. Phenotypic costs are assessed from patterns...... of covariation, typically between a focal trait and a separate trait relevant to fitness. Plasticity costs, separable from phenotypic costs, are gauged by comparing the fitness of genotypes with equivalent phenotypes within two environments but differing in plasticity and fitness. Subtleties associated with both...... types of costs are illustrated by a body of work addressing predator-induced plasticity. Such subtleties, and potential interplay between the two types of costs, have also been addressed, often in studies involving genetic model organisms. In some instances, investigators have pinpointed the mechanistic...

  7. Search for disappearing tracks

    CERN Document Server

    INSPIRE-00024550

    2015-01-01

    We present a search for long-lived charged particles that decay within the CMS detector and produce the signature of a disappearing track. Disappearing tracks are identified as those with little or no associated calorimeter energy deposits and with missing hits in the outer layers of the tracker. The search uses proton-proton collision data recorded at $\\sqrt{s} = 8$ TeV that corresponds to an integrated luminosity of 19.5 fb$^{-1}$. The results of the search are interpreted in the context of the anomaly-mediated supersymmetry breaking model and in terms of the phenomenological MSSM.

  8. Tracking Your Development

    CERN Document Server

    Hennum, Kelly M

    2011-01-01

    This book provides you with the means to set development goals and to track your progress on achieving them. It can help you efficiently gather and make sense of information about your progress and avoid common pitfalls that can block your development. Tracking your development can be captures in a few steps: articulating your goal, creating an action plan, gathering information about your behavior, indentifying barriers and support, and revising your action plan. Taking these steps will greatly increase the likelihood of achieving your goals.

  9. Spin tracking in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Luccio, A.U. [Brookhaven National Lab., Upton, NY (United States); Katayama, T. [Univ. of Tokyo (Japan); Wu, H. [Riken Inst., Tokyo (Japan)

    1997-07-01

    In the acceleration of polarized protons in RHIC many spin depolarizing resonances are encountered. Helical Siberian snakes will be used to overcome depolarizing effects. The behavior of polarization can be studied by numerical tracking in a model accelerator. That allows one to check the strength of the resonances, to study the effect of snakes, to find safe lattice tune regions, and finally to study the operation of special devices like spin flippers. In this paper the authors describe numerical spin tracking. Results show that, for the design corrected distorted orbit and the design beam emittance, the polarization of the beam will be preserved in the whole range of proton energies in RHIC.

  10. Object Tracking with RFID

    Science.gov (United States)

    Yamada, Kou; Uchida, Seiichi; Taniguchi, Rin-Ichiro

    This paper reports a new method for visual tracking of humans using active RFID technology. Previous studies were based on the assumption that the radio intensity from an RFID tag will be linearly proportional to the distance between the tag and the antenna or will remain unchanged; however, in reality, the intensity fluctuates significantly and changes drastically with a small change in the environment. The proposed method helps to overcome this problem by using only accurate binary information that reveals whether the target person is close to the antenna. Several experimental results have shown that the information from the RFID tag was useful for reliable tracking of humans.

  11. Military tracked vehicles

    CERN Document Server

    Hansen, Grace

    2016-01-01

    Tracked vehicles are important to militaries around the world, since they're usually supporting and carrying ground troops. Readers will learn what tracks are and why they're necessary for large, frontline battle tanks like the Bradley M2 Abrams. Big full-bleed photographs, new glossary terms, and a close up look at a vehicle will keep readers wanting more! Aligned to Common Core Standards and correlated to state standards. Abdo Kids Jumbo is an imprint of Abdo Kids, a division of ABDO.

  12. PLASMA GASIFICATION OF WASTE PLASTICS

    Directory of Open Access Journals (Sweden)

    Tadeusz Mączka

    2013-01-01

    Full Text Available The article presents the process of obtaining liquid fuels and fuel gas in the process of plasma processing of organic materials, including waste plastics. The concept of plasma pyrolysis of plastics was presented and on its basis a prototype installation was developed. The article describes a general rule of operating the installation and its elements in the process and basic operation parameters determined during its start-up. Initial results of processing plastics and the directions further investigations are also discussed. The effect of the research is to be the design of effective technology of obtaining fuels from gasification/pyrolysis of organic waste and biomass.

  13. Circadian Regulation of Synaptic Plasticity

    Directory of Open Access Journals (Sweden)

    Marcos G. Frank

    2016-07-01

    Full Text Available Circadian rhythms refer to oscillations in biological processes with a period of approximately 24 h. In addition to the sleep/wake cycle, there are circadian rhythms in metabolism, body temperature, hormone output, organ function and gene expression. There is also evidence of circadian rhythms in synaptic plasticity, in some cases driven by a master central clock and in other cases by peripheral clocks. In this article, I review the evidence for circadian influences on synaptic plasticity. I also discuss ways to disentangle the effects of brain state and rhythms on synaptic plasticity.

  14. Construction and performance of the L3 central tracking detector

    Science.gov (United States)

    Beissel, F.; Böhm, A.; Bosseler, K.; Camps, C.; Commichau, V.; Deutschmann, M.; Frohn, H.; Jansen, D.; Göttlicher, P.; Grooten, J.; Hangarter, K.; Herten, U.; Liebmann, H.; Mnich, J.; Möller, M.; Pahlke, R.; Reuter, W.; Rieb, N.; Rinsche, U.; Röhner, S.; Rose, J.; Quadflieg, K.; Schmitz, P.; Schulte, R.; Schulte, S.; Schultze, K.; Spickermann, T.; Starosta, R.; Szczesny, H.; Sassowsky, M.; Tonutti, M.; Virnich, H.; Winands, T.; Sens, J. C.; Bourilkov, D.; Schotanus, D. J.; Akbari, H.; Bao, J.; Chien, C.-Y.; Fisher, P.; Gougas, A.; Newman, D.; Orndorff, J.; Pevsner, A.; Spangler, J.; Spartiotis, C.; Alverson, G.; Glaubman, M.; Leedom, I.; Reucroft, S.; Taylor, L.; Barbier, G.; Béné, P.; Bourquin, M.; Field, J. H.; Forconi, G.; La Marra, D.; Léger, A.; Masciocchi, F.; Perrier, J.; Perrin, E.; Produit, N.; Richeux, J. P.; Weber, M.; Antonov, L.; Botev, S.; Krastev, V.; Orlinov, I.; Hasan, A.; Sultanov, G.; Vikas, P.; Haerdi, E.; Deiters, K.; Donat, A.; Friebel, W.; Heller, R.; Kirsch, S.; Krankenhagen, R.; Lange, W.; Leiste, R.; Lohmann, W.; Lustermann, W.; Röser, U.; Peng, Y.; Tonisch, F.; Trowitzsch, G.; Vogt, H.; Wilhelmi, M.; Anderhub, H.; Baur, W.; Beauvais, F.; Behner, F.; Behrens, J.; Betev, B.; Biland, A.; Djambazov, L.; Dhina, M.; Fehlmann, J.; Hänsli, M.; Herrmann, J.; Hofer, H.; Horisberger, U.; Isiksal, E.; Jung, H.; Kästli, W.; Lanius, K.; Lue, X.; Neyer, C.; Maolinbay, M.; McNally, D.; Okle, M.; Pohl, M.; Rahal-Callot, G.; Ren, D.; Schuijlenburg, H.; Stöhr, B.; Suter, H.; Thürig, H.; Ulbricht, J.; Viertel, G. M.; von Gunten, H. P.; Waldmeier, S.; Weber, J.; Zehnder, L.; Zemp, P.

    1993-07-01

    The L3 central tracking detector has been in operation since the start-up of LEP (Large Electron Positron collider) in 1989. This detector consists of a Time Expansion Chamber (TEC), a layer of Plastic Scintillating Fibers and a Z-chamber. The TEC gives a high spatial resolution and an excellent multi-track reconstruction capability. The fibers are designed to calibrate the drift velocity with high precision. The Z-Chamber provides TEC with accurate information about the z-coordinates of the tracks. A description of the design and the infrastructure of these three detectors, including the readout and data acquisition system, is given. The performance of the detectors during the 1990 and 1991 LEP running periods is presented.

  15. The Utility of Outcome Studies in Plastic Surgery

    Directory of Open Access Journals (Sweden)

    Hani Sinno, MD, MEng

    2014-07-01

    Full Text Available Summary: Outcome studies help provide the evidence-based science rationalizing treatment end results that factor the experience of patients and the impact on society. They improve the recognition of the shortcoming in clinical practice and provide the foundation for the development of gold standard care. With such evidence, health care practitioners can develop evidence-based justification for treatments and offer patients with superior informed consent for their treatment options. Furthermore, health care and insurance agencies can recognize improved cost-benefit options in the purpose of disease prevention and alleviation of its impact on the patient and society. Health care outcomes are ultimately measured by the treatment of disease, the reduction of symptoms, the normalization of laboratory results and physical measures, saving a life, and patient satisfaction. In this review, we outline the tools available to measure outcomes in plastic surgery and subsequently allow the objective measurements of plastic surgical conditions. Six major outcome categories are discussed: (1 functional measures; (2 preference-based measures and utility outcome scores; (3 patient satisfaction; (4 health outcomes and time; (5 other tools: patient-reported outcome measurement information system, BREAST-Q, and Tracking Operations and Outcomes for Plastic Surgeons; and (6 cost-effectiveness analysis. We use breast hypertrophy requiring breast reduction as an example throughout this review as a representative plastic surgical condition with multiple treatments available.

  16. The Utility of Outcome Studies in Plastic Surgery

    Science.gov (United States)

    Sinno, Hani; Dionisopoulos, Tassos; Slavin, Sumner A.; Ibrahim, Ahmed M. S.; Chung, Kevin C.

    2014-01-01

    Summary: Outcome studies help provide the evidence-based science rationalizing treatment end results that factor the experience of patients and the impact on society. They improve the recognition of the shortcoming in clinical practice and provide the foundation for the development of gold standard care. With such evidence, health care practitioners can develop evidence-based justification for treatments and offer patients with superior informed consent for their treatment options. Furthermore, health care and insurance agencies can recognize improved cost-benefit options in the purpose of disease prevention and alleviation of its impact on the patient and society. Health care outcomes are ultimately measured by the treatment of disease, the reduction of symptoms, the normalization of laboratory results and physical measures, saving a life, and patient satisfaction. In this review, we outline the tools available to measure outcomes in plastic surgery and subsequently allow the objective measurements of plastic surgical conditions. Six major outcome categories are discussed: (1) functional measures; (2) preference-based measures and utility outcome scores; (3) patient satisfaction; (4) health outcomes and time; (5) other tools: patient-reported outcome measurement information system, BREAST-Q, and Tracking Operations and Outcomes for Plastic Surgeons; and (6) cost-effectiveness analysis. We use breast hypertrophy requiring breast reduction as an example throughout this review as a representative plastic surgical condition with multiple treatments available. PMID:25426372

  17. Recycling of Reinforced Plastics

    Science.gov (United States)

    Adams, R. D.; Collins, Andrew; Cooper, Duncan; Wingfield-Digby, Mark; Watts-Farmer, Archibald; Laurence, Anna; Patel, Kayur; Stevens, Mark; Watkins, Rhodri

    2014-02-01

    This work has shown is that it is possible to recycle continuous and short fibre reinforced thermosetting resins while keeping almost the whole of the original material, both fibres and matrix, within the recyclate. By splitting, crushing hot or cold, and hot forming, it is possible to create a recyclable material, which we designate a Remat, which can then be used to remanufacture other shapes, examples of plates and tubes being demonstrated. Not only can remanufacturing be done, but it has been shown that over 50 % of the original mechanical properties, such as the E modulus, tensile strength, and interlaminar shear strength, can be retained. Four different forms of composite were investigated, a random mat Glass Fibre Reinforced Plastic (GFRP) bathroom component and boat hull, woven glass and carbon fibre cloth impregnated with an epoxy resin, and unidirectional carbon fibre pre-preg. One of the main factors found to affect composite recyclability was the type of resin matrix used in the composite. Thermoset resins tested were shown to have a temperature range around the Glass Transition Temperature (Tg) where they exhibit ductile behaviour, hence aiding reforming of the material. The high-grade carbon fibre prepreg was found to be less easy to recycle than the woven of random fibre laminates. One method of remanufacturing was by heating the Remat to above its glass transition temperature, bending it to shape, and then cooling it. However, unless precautions are taken, the geometric form may revert. This does not happen with the crushed material.

  18. Helene: A Plastic Model

    Science.gov (United States)

    Umurhan, O. M.; Moore, J. M.; Howard, A. D.; Schenk, P.; White, O. L.

    2014-12-01

    Helene, the Saturnian L4 Trojan satellite co-orbiting Dionne and sitting within the E-ring, possesses an unusual morphology characteristic of broad km-scale basins and depressions and a generally smooth surface patterned with streaks and grooves which are indicative of non-typical mass transport. Elevation angles do not appear to exceed 10o at most. The nature and origin of the surface materials forming these grooved patterns is unknown. Given the low surface gravity (plastic-like flow like a Bingham fluid, we setup and test a number of likely scenarios to explain the observations. The numerical results qualitatively indicate that treating the mass-wasting materials as a Bingham material reproduces many of the qualitative features observed. We also find that in those simulations in which accretion is concomitant with Bingham mass-wasting, the long time-evolution of the surface flow shows intermittency in the total surface activity (defined as total surface integral of the absolute magnitude of the mass-flux). Detailed analyses identify the locations where this activity is most pronounced and we will discuss these and its implications in further detail.

  19. Plasticity and creep of metals

    CERN Document Server

    Rusinko, Andrew

    2011-01-01

    Here is a systematic presentation of the postulates, theorems and principles of mathematical theories of plasticity and creep in metals, and their applications. Special attention is paid to analysis of the advantages and shortcomings of the classical theories.

  20. Radiation damage in plastic detectors

    International Nuclear Information System (INIS)

    Balcazar, M.; Tavera, L.

    2007-01-01

    Full text: The damage induced by ionizing radiation in plastics produce a wide diversity of changes in the either the whole polymer structure or a localized high destruction. The first effect is achieved by using gamma and/or electron irradiation, whereas the second is carry out by employing positive ions irradiation. The damage intensity can be controlled by the dose delivery to the plastic, in the first case and by the rate of energy loss of the incident ion in the second case. Damage deepness in the thickness of the plastic, depends of radiation energy, although, attenuation effects have to be considered for gamma and electron irradiation. This paper presents an overview of those effects, the applications for radiation dosimetry and the production of micro and nano pores, as well as the methodology for control all parameters involved in the damage. Techniques for visualization the localized high destruction in the plastics are also presented. (Author)

  1. Exceptional plasticity of silicon nanobridges

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Tadashi; Sato, Takaaki; Toshiyoshi, Hiroshi; Collard, Dominique; Fujita, Hiroyuki [University of Tokyo, Institute of Industrial Science, 4-6-1 Komaba Meguro, Tokyo 153-8505 (Japan); Cleri, Fabrizio [Institut d' Electronique Microelectronique et Nanotechnologie (CNRS UMR 8520), Universite de Lille I, Avenue Poincare BP60069 59652 Villeneuve d' Ascq (France); Kakushima, Kuniyuki [Tokyo Institute of Technology, 4259, Nagatsuda, Midori, Yokohama, Kanagawa 226-8502 (Japan); Mita, Makoto [Department of Spacecraft Engineering, Japan Aerospace Exploration Agency, 3-1-1, Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Miyata, Masaki; Itamura, Noriaki; Sasaki, Naruo [Department of Materials and Life Sciences, Seikei University, 3-3-1, Kitamachi, Kichijoji, Musashino, Tokyo 180-8633 (Japan); Endo, Junji, E-mail: tadashii@iis.u-tokyo.ac.jp [FK Optical laboratory, 1-13-4 Nakano Niiza Saitama, 352-0005 (Japan)

    2011-09-02

    The plasticity of covalently bonded materials is a subject at the forefront of materials science, bearing on a wide range of technological and fundamental aspects. However, covalent materials fracture in a brittle manner when the deformation exceeds just a few per cent. It is predicted that a macroscopically brittle material like silicon can show nanoscale plasticity. Here we report the exceptional plasticity observed in silicon nanocontacts ('nanobridges') at room temperature using a special experimental setup combining a transmission electron microscope and a microelectromechanical system. When accounting for surface diffusion, we succeeded in elongating the nanocontact into a wire-like structure, with a fivefold increase in volume, up to more than twenty times the original length. Such a large plasticity was caused by the stress-assisted diffusion and the sliding of the intergranular, amorphous-like material among the nanocrystals.

  2. Second sound tracking system

    Science.gov (United States)

    Yang, Jihee; Ihas, Gary G.; Ekdahl, Dan

    2017-10-01

    It is common that a physical system resonates at a particular frequency, whose frequency depends on physical parameters which may change in time. Often, one would like to automatically track this signal as the frequency changes, measuring, for example, its amplitude. In scientific research, one would also like to utilize the standard methods, such as lock-in amplifiers, to improve the signal to noise ratio. We present a complete He ii second sound system that uses positive feedback to generate a sinusoidal signal of constant amplitude via automatic gain control. This signal is used to produce temperature/entropy waves (second sound) in superfluid helium-4 (He ii). A lock-in amplifier limits the oscillation to a desirable frequency and demodulates the received sound signal. Using this tracking system, a second sound signal probed turbulent decay in He ii. We present results showing that the tracking system is more reliable than those of a conventional fixed frequency method; there is less correlation with temperature (frequency) fluctuation when the tracking system is used.

  3. Energy Tracking Diagrams

    Science.gov (United States)

    Scherr, Rachel E.; Harrer, Benedikt W.; Close, Hunter G.; Daane, Abigail R.; DeWater, Lezlie S.; Robertson, Amy D.; Seeley, Lane; Vokos, Stamatis

    2016-01-01

    Energy is a crosscutting concept in science and features prominently in national science education documents. In the "Next Generation Science Standards," the primary conceptual learning goal is for learners to conserve energy as they "track" the transfers and transformations of energy within, into, or out of the system of…

  4. Tracking Politics with POWER

    Science.gov (United States)

    Moreira, Silvio; Batista, David S.; Carvalho, Paula; Couto, Francisco M.; Silva, Mario J.

    2013-01-01

    Purpose: POWER is an ontology of political processes and entities. It is designed for tracking politicians, political organizations and elections, both in mainstream and social media. The aim of this paper is to propose a data model to describe political agents and their relations over time. Design/methodology/approach: The authors propose a data…

  5. Tracking, say, SKYPE Locations

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Tracking, say, SKYPE Locations. Real Time Communication: Peer-to-Peer (P2P). Datagram flows between the two conversing partners; Exposes the IP addresses of all the participants to one another. If A knows B's VoIP ID, she can establish a call with Bob & obtain his current ...

  6. Tracking Self into Place

    Science.gov (United States)

    Piersol, Laura

    2010-01-01

    In an effort to figure out what it means to educate "ecologically," I decided to track down some of the stories that I was living, telling and making as an educator. I ended up lost in the house of environmental education, stuck within the rooms of ecological science and political advocacy. Outside on the lawn sat the story of place…

  7. Eye tracking social preferences

    NARCIS (Netherlands)

    Jiang, Ting; Potters, Jan; Funaki, Yukihiko

    We hypothesize that if people are motivated by a particular social preference, then choosing in accordance with this preference will lead to an identifiable pattern of eye movements. We track eye movements while subjects make choices in simple three-person distribution experiments. We characterize

  8. Forward tracking detectors

    Indian Academy of Sciences (India)

    In order to get a forward tracking that fulfils the needs, it has to be implemented in the design of the detectors from the beginning. Past experience shows that this part was often underestimated and upgrades at a later stage could not deliver the required performance because the needed space was already taken by other ...

  9. Muon tracking system with Silicon Photomultipliers

    Energy Technology Data Exchange (ETDEWEB)

    Arneodo, F.; Benabderrahmane, M.L.; Dahal, S. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Di Giovanni, A., E-mail: adriano.digiovanni@nyu.edu [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Pazos Clemens, L. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Candela, A.; D' Incecco, M.; Sablone, D. [Gran Sasso National Laboratory of INFN, Assergi (Italy); Franchi, G. [AGE Scientific Srl, Capezzano Pianore (Italy)

    2015-11-01

    We report the characterisation and performance of a low cost muon tracking system consisting of plastic scintillator bars and Silicon Photomultipliers equipped with a customised front-end electronics based on a fast preamplifier network. This system can be used as a detector test bench for astroparticle physics and for educational and outreach purposes. We investigated the device behaviour in self-trigger and coincidence mode, without using LED and pulse generators, showing that with a relatively simple set up a complete characterisation work can be carried out. A high definition oscilloscope, which can easily be found in many university physics or engineering departments, has been used for triggering and data acquisition. Its capabilities have been exploited to discriminate real particles from the background.

  10. Office-Based Plastic Surgery

    OpenAIRE

    Ersek, Robert A.

    2007-01-01

    Office-based plastic surgery began in the 1960s and has expanded exponentially since then. The majority of plastic surgeons now have their own office-based facilities, and every elective aesthetic procedure from hair transplantation to abdominoplasty and breast reduction can be done as an outpatient procedure with tremendous increases in efficiency, safety, and time. We started with a single room and have expanded to three operating rooms, two specific preoperative, postoperative private room...

  11. Biocide Usage in Plastic Products

    OpenAIRE

    Kavak, Nergizhan; Çakır, Ayşegül; Koltuk, Fatmagül; Uzun, Utku

    2015-01-01

    People’s demand of improving their life quality caused to the term of hygiene become popular and increased the tendency to use more reliable and healthy products. This tendency makes the continuous developments in the properties of the materials used in manufactured goods compulsory. It is possible to create anti-bacterial plastic products by adding biocidal additives to plastic materials which have a wide-range of application in the areas such as health (medicine), food and many other indust...

  12. Computational materials science: Nanoscale plasticity

    DEFF Research Database (Denmark)

    Jacobsen, Karsten Wedel; Schiøtz, Jakob

    2002-01-01

    How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour.......How does plastic deformation of polycrystalline materials with grain sizes less than 100 nm look at the atomic scale? A large-scale molecular dynamics simulation of nanocrystalline alluminium reveals some surprising behaviour....

  13. Tracking Virtual Trajectories

    Science.gov (United States)

    Stone, Leland S.; Beutter, Brent R.; Lorenceau, Jean D.; Null, Cynthia H. (Technical Monitor)

    1996-01-01

    Current models of smooth pursuit eye movements assume that it is largely driven by retinal image motion. We tested this hypothesis by measuring pursuit of elliptical motion (3.2s, 0.9 Hz, 1.4 deg x 1.6 deg, 4 randomly interleaved phases) of either a small spot ("real" motion) or of a line-figure diamond viewed through apertures such that only the motion of four isolated oblique line segments was visible ("virtual" motion). Each segment moved sinusoidally along a linear trajectory yet subjects perceived a diamond moving along an elliptical path behind the aperture. We found, as expected, that real motion produced accurate tracking (N = 2) with mean gain (over horizontal and vertical) of 0.9, mean phase of -6 deg (lag), mean relative phase (H vs V) of 90 +/- 8 deg (RMS error). Virtual motion behind an X-shaped aperture (N= 4 with one naive) yielded a mean gain of 0.7, mean phase of -11 deg, mean relative phase of 87 +/- 15 deg. We also measured pursuit with the X-shaped aperture using a higher segment luminance which prevents the segments from being grouped into a coherently moving diamond while keeping the motion otherwise identical. In this incoherent case, the same four subjects no longer showed consistent elliptical tracking (RMS error in relative phase rose to 60 deg) suggesting that perceptual coherence is critical. Furthermore, to rule out tracking of the centroid, we also used vertical apertures so that all segment motion was vertical (N = 3). This stimulus still produced elliptical tracking (mean relative phase of 84 +/- 19 deg), albeit with a lower gain (0.6). These data show that humans can track moving objects reasonably accurately even when the trajectory can only be derived by spatial integration of motion signals. Models that merely seek to minimize retinal or local stimulus motion cannot explain these results.

  14. A non-linear elastic constitutive framework for replicating plastic deformation in solids.

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Scott Alan; Schunk, Peter Randall

    2014-02-01

    Ductile metals and other materials typically deform plastically under large applied loads; a behavior most often modeled using plastic deformation constitutive models. However, it is possible to capture some of the key behaviors of plastic deformation using only the framework for nonlinear elastic mechanics. In this paper, we develop a phenomenological, hysteretic, nonlinear elastic constitutive model that captures many of the features expected of a plastic deformation model. This model is based on calculating a secant modulus directly from a materials stress-strain curve. Scalar stress and strain values are obtained in three dimensions by using the von Mises invariants. Hysteresis is incorporated by tracking an additional history variable and assuming an elastic unloading response. This model is demonstrated in both single- and multi-element simulations under varying strain conditions.

  15. Radiation Measured for Chinese Satellite SJ-10 Space Mission

    Science.gov (United States)

    Zhou, Dazhuang; Sun, Yeqing; Zhang, Binquan; Zhang, Shenyi; Sun, Yueqiang; Liang, Jinbao; Zhu, Guangwu; Jing, Tao; Yuan, Bin; Zhang, Huanxin; Zhang, Meng; Wang, Wei; Zhao, Lei

    2018-02-01

    Space biological effects are mainly a result of space radiation particles with high linear energy transfer (LET); therefore, accurate measurement of high LET space radiation is vital. The radiation in low Earth orbits is composed mainly of high-energy galactic cosmic rays (GCRs), solar energetic particles, particles of radiation belts, the South Atlantic Anomaly, and the albedo neutrons and protons scattered from the Earth's atmosphere. CR-39 plastic nuclear track detectors sensitive to high LET are the best passive detectors to measure space radiation. The LET method that employs CR-39 can measure all the radiation LET spectra and quantities. CR-39 detectors can also record the incident directions and coordinates of GCR heavy ions that pass through both CR-39 and biosamples, and the impact parameter, the distance between the particle's incident point and the seed's spore, can then be determined. The radiation characteristics and impact parameter of GCR heavy ions are especially beneficial for in-depth research regarding space radiation biological effects. The payload returnable satellite SJ-10 provided an excellent opportunity to investigate space radiation biological effects with CR-39 detectors. The space bio-effects experiment was successfully conducted on board the SJ-10 satellite. This paper introduces space radiation in low Earth orbits and the LET method in radiation-related research and presents the results of nuclear tracks and biosamples hitting distributions of GCR heavy ions, the radiation LET spectra, and the quantities measured for the SJ-10 space mission. The SJ-10 bio-experiment indicated that radiation may produce significant bio-effects.

  16. Experiments with elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Randrup-Thomsen, S.; Ditlevsen, Ove Dalager

    1999-01-01

    Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

  17. Experiments with elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Randrup-thomsen, Søren; Ditlevsen, Ove Dalager

    1996-01-01

    Plastic displacements of a Gaussian white noise excited three degrees of freedom non-ideal elasto-plastic oscillator are measured in laboratory experiments and the plastic displacements are compared to computer simulated results for the corresponding ideal elasto-plastic oscillator. The comparative...

  18. 49 CFR 192.59 - Plastic pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.59 Section 192.59 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Materials § 192.59 Plastic pipe. (a) New plastic pipe... specification; and (2) It is resistant to chemicals with which contact may be anticipated. (b) Used plastic pipe...

  19. 49 CFR 192.281 - Plastic pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Plastic pipe. 192.281 Section 192.281... Plastic pipe. (a) General. A plastic pipe joint that is joined by solvent cement, adhesive, or heat fusion may not be disturbed until it has properly set. Plastic pipe may not be joined by a threaded joint or...

  20. Better features to track by estimating the tracking convergence region

    NARCIS (Netherlands)

    Zivkovic, Z.; van der Heijden, Ferdinand; Kasturi, R.; Laurendeau, D.; Suen, C.

    2002-01-01

    Reliably tracking key points and textured patches from frame to frame is the basic requirement for many bottom- up computer vision algorithms. The problem of selecting the features that can be tracked well is addressed here. The Lucas- Kcsnade tracking procedure is commonly used. We propose a method

  1. mechanical sun mechanical sun-tracking techn tracking techn power ...

    African Journals Online (AJOL)

    User

    MECHANICAL SUN-TRACKING TECHN. TRACKING TECHN. POWER POINT TRACKING OF. D. B. N.. 1,2,3DEPARTMENT OF ELECTRICAL. Email addresses addresses addresses: 1 damian.nnadi@unn.edu.ng. ABSTRACT. This paper elucidates a single axis. This paper elucidates a single axis solar tracker syst.

  2. Evolution of phenotypic plasticity in colonizing species.

    Science.gov (United States)

    Lande, Russell

    2015-05-01

    I elaborate an hypothesis to explain inconsistent empirical findings comparing phenotypic plasticity in colonizing populations or species with plasticity from their native or ancestral range. Quantitative genetic theory on the evolution of plasticity reveals that colonization of a novel environment can cause a transient increase in plasticity: a rapid initial increase in plasticity accelerates evolution of a new optimal phenotype, followed by slow genetic assimilation of the new phenotype and reduction of plasticity. An association of colonization with increased plasticity depends on the difference in the optimal phenotype between ancestral and colonized environments, the difference in mean, variance and predictability of the environment, the cost of plasticity, and the time elapsed since colonization. The relative importance of these parameters depends on whether a phenotypic character develops by one-shot plasticity to a constant adult phenotype or by labile plasticity involving continuous and reversible development throughout adult life. © 2014 John Wiley & Sons Ltd.

  3. Vehicle track interaction safety standards

    Science.gov (United States)

    2014-04-02

    Vehicle/Track Interaction (VTI) Safety Standards aim to : reduce the risk of derailments and other accidents attributable : to the dynamic interaction between moving vehicles and the : track over which they operate. On March 13, 2013, the Federal : R...

  4. Quality Assurance Training Tracking (QATTS)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This is metadata documentation for the Quality Assurance Training Tracking System (QATTS) which tracks Quality Assurace training given by R7 QA staff to in-house...

  5. Elimination of Plastic Polymers in Natural Environments

    OpenAIRE

    Ramirez-Ekner, Sofia; Bidstrup, Marie Juliane Svea; Brusen, Nicklas Hald; Rugaard-Morgan, Zsa-Zsa Sophie Oona Ophelia

    2017-01-01

    Plastic production and consumption continues to rise and subsequently plastic waste continues to accumulates in natural environments, causing harm to ecosystems.The aim of this paper was to come up with a way to utilize organisms, that have been identified to produce plastic degrading enzymes, as a waste disposal technology. This review includes accounts of plastic production rates, the occurrence of plastic in natural environments and the current waste management systems to create an underst...

  6. Tracking migrating birds

    DEFF Research Database (Denmark)

    Willemoes, Mikkel

    and many experiments are only becoming possible with the current development of tracking technologies. During this thesis work I have been tracking the poorly known movements of several species of long-distance migrants and document highly complex migration patterns. In three manuscripts these movements......, and conclude that the currently believed theoretical framework is insufficient to explain the observed performance. The other study investigates the ability of a displaced experienced migrant to navigate back to the normal migration route. It documents the capability, but also finds interesting patterns...... were related to the yearly progression of an environmental surrogate for food availability along the course of migration. In one species, with multiple, different non-breeding staging sites, environmental conditions explain movements well and also how yearly differences explain differences in timing...

  7. Structural Sparse Tracking

    KAUST Repository

    Zhang, Tianzhu

    2015-06-01

    Sparse representation has been applied to visual tracking by finding the best target candidate with minimal reconstruction error by use of target templates. However, most sparse representation based trackers only consider holistic or local representations and do not make full use of the intrinsic structure among and inside target candidates, thereby making the representation less effective when similar objects appear or under occlusion. In this paper, we propose a novel Structural Sparse Tracking (SST) algorithm, which not only exploits the intrinsic relationship among target candidates and their local patches to learn their sparse representations jointly, but also preserves the spatial layout structure among the local patches inside each target candidate. We show that our SST algorithm accommodates most existing sparse trackers with the respective merits. Both qualitative and quantitative evaluations on challenging benchmark image sequences demonstrate that the proposed SST algorithm performs favorably against several state-of-the-art methods.

  8. The track nanotechnology

    International Nuclear Information System (INIS)

    Waheed, A.; Forsyth, D.; Watts, A.; Saad, A.F.; Mitchell, G.R.; Farmer, M.; Harris, P.J.F.

    2009-01-01

    The discipline now called Solid State Nuclear Track Detection (SSNTD) dates back to 1958 and has its roots in the United Kingdom. Its strength stems chiefly from factors such as its simplicity, small geometry, permanent maintenance of the nuclear record and other diversified applications. A very important field with exciting applications reported recently in conjuction with the nuclear track technique is nanotechnology, which has applications in biology, chemistry, industry, medicare and health, information technology, biotechnology, and metallurgical and chemical technologies. Nanotechnology requires material design followed by the study of the quantum effects for final produced applications in sensors, medical diagnosis, information technology to name a few. We, in this article, present a review of past and present applications of SSNTD suggesting ways to apply the technique in nanotechnology, with special reference to development of nanostructure for applications utilising nanowires, nanofilters and sensors.

  9. Labeling uncertainty in multitarget tracking

    NARCIS (Netherlands)

    Aoki, E.H.; Mandal, Pranab K.; Svensson, Lennart; Boers, Y.; Bagchi, Arunabha

    In multitarget tracking, the problem of track labeling (assigning labels to tracks) is an ongoing research topic. The existing literature, however, lacks an appropriate measure of uncertainty related to the assigned labels that has a sound mathematical basis as well as clear practical meaning to the

  10. Thermal Tracking of Sports Players

    DEFF Research Database (Denmark)

    Gade, Rikke; Moeslund, Thomas B.

    2014-01-01

    We present here a real-time tracking algorithm for thermal video from a sports game. Robust detection of people includes routines for handling occlusions and noise before tracking each detected person with a Kalman filter. This online tracking algorithm is compared with a state-of-the-art offline...

  11. The fission track method

    International Nuclear Information System (INIS)

    Hansen, K.

    1990-01-01

    During the last decade fission track (FT) analysis has evolved as an important tool in exploration for hydrocarbon resources. Most important is this method's ability to yield information about temperatures at different times (history), and thus relate oil generation and time independently of other maturity parameters. The purpose of this paper is to introduce the basics of the method and give an example from the author's studies. (AB) (14 refs.)

  12. SOFIA tracking image simulation

    Science.gov (United States)

    Taylor, Charles R.; Gross, Michael A. K.

    2016-09-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) tracking camera simulator is a component of the Telescope Assembly Simulator (TASim). TASim is a software simulation of the telescope optics, mounting, and control software. Currently in its fifth major version, TASim is relied upon for telescope operator training, mission planning and rehearsal, and mission control and science instrument software development and testing. TASim has recently been extended for hardware-in-the-loop operation in support of telescope and camera hardware development and control and tracking software improvements. All three SOFIA optical tracking cameras are simulated, including the Focal Plane Imager (FPI), which has recently been upgraded to the status of a science instrument that can be used on its own or in parallel with one of the seven infrared science instruments. The simulation includes tracking camera image simulation of starfields based on the UCAC4 catalog at real-time rates of 4-20 frames per second. For its role in training and planning, it is important for the tracker image simulation to provide images with a realistic appearance and response to changes in operating parameters. For its role in tracker software improvements, it is vital to have realistic signal and noise levels and precise star positions. The design of the software simulation for precise subpixel starfield rendering (including radial distortion), realistic point-spread function as a function of focus, tilt, and collimation, and streaking due to telescope motion will be described. The calibration of the simulation for light sensitivity, dark and bias signal, and noise will also be presented

  13. Patient tracking system

    International Nuclear Information System (INIS)

    Chapman, L.J.; Hakimi, R.; Salehi, D.; McCord, T.; Zionczkowski, B.; Churchill, R.

    1987-01-01

    This exhibit describes computer applications in monitoring patient tracking in radiology and the collection of management information (technologist productivity, patient waiting times, repeat rate, room utilization) and quality assurance information. An analysis of the reports that assist in determining staffing levels, training needs, and patient scheduling is presented. The system is designed to require minimal information input and maximal information output to assist radiologists, quality assurance coordinators, and management personnel in departmental operations

  14. Tracking communications change

    International Nuclear Information System (INIS)

    Latimer, Cole

    2010-01-01

    While personal communications on a minesite is critical, the additional equipment and weight miners are forced to contend with hampers work. Often bulky, and fairly heavy, mining communications equipment has not been known for its lightweight manufacture. To overcome this and give miners some relief, NL Technologies has developed a two way messaging and tracking device that is incorporated into their existing cap lamps, the Northern Light Cap Lamp, to service this communications need

  15. Cerebellar motor learning: when is cortical plasticity not enough?

    Directory of Open Access Journals (Sweden)

    John Porrill

    2007-10-01

    Full Text Available Classical Marr-Albus theories of cerebellar learning employ only cortical sites of plasticity. However, tests of these theories using adaptive calibration of the vestibulo-ocular reflex (VOR have indicated plasticity in both cerebellar cortex and the brainstem. To resolve this long-standing conflict, we attempted to identify the computational role of the brainstem site, by using an adaptive filter version of the cerebellar microcircuit to model VOR calibration for changes in the oculomotor plant. With only cortical plasticity, introducing a realistic delay in the retinal-slip error signal of 100 ms prevented learning at frequencies higher than 2.5 Hz, although the VOR itself is accurate up to at least 25 Hz. However, the introduction of an additional brainstem site of plasticity, driven by the correlation between cerebellar and vestibular inputs, overcame the 2.5 Hz limitation and allowed learning of accurate high-frequency gains. This "cortex-first" learning mechanism is consistent with a wide variety of evidence concerning the role of the flocculus in VOR calibration, and complements rather than replaces the previously proposed "brainstem-first" mechanism that operates when ocular tracking mechanisms are effective. These results (i describe a process whereby information originally learnt in one area of the brain (cerebellar cortex can be transferred and expressed in another (brainstem, and (ii indicate for the first time why a brainstem site of plasticity is actually required by Marr-Albus type models when high-frequency gains must be learned in the presence of error delay.

  16. Formation of cortical plasticity in older adults following tDCS and motor training.

    Directory of Open Access Journals (Sweden)

    Alicia M Goodwill

    2013-12-01

    Full Text Available Neurodegeneration accompanies the process of natural ageing, reducing the ability to perform functional daily activities. Transcranial direct current stimulation (tDCS alters neuronal excitability and motor performance; however its beneficial effect on the induction of primary motor cortex (M1 plasticity in older adults is unclear. Moreover, little is known as to whether the tDCS electrode arrangement differentially affects M1 plasticity and motor performance in this population. In a double-blinded, cross-over trial, we compared unilateral, bilateral and sham tDCS combined with visuomotor tracking, on M1 plasticity and motor performance of the non-dominant upper limb, immediately post and 30 minutes following stimulation. We found (a unilateral and bilateral tDCS decreased tracking error by 12-22% at both time points; with sham decreasing tracking error by 10% at 30 minutes only, (b at both time points, motor evoked potentials (MEPs were facilitated (38-54% and short-interval intracortical inhibition (SICI was released (21-36% for unilateral and bilateral conditions relative to sham, (c there were no differences between unilateral and bilateral conditions for any measure. These findings suggest that tDCS modulated elements of M1 plasticity, which improved motor performance irrespective of the electrode arrangement. The results provide preliminary evidence indicating that tDCS is a safe non-invasive tool to preserve or improve neurological function and motor control in older adults.

  17. Blood response to plasticized poly(vinyl chloride): dependence of fibrinogen adsorption on plasticizer selection and surface plasticizer level.

    Science.gov (United States)

    Zhao, X B; Courtney, J M

    2003-10-01

    The high level of plasticizer in plasticized poly(vinyl chloride) (PVC) ensures that plasticizer selection has an important influence on the suitability of PVC to function in blood-contacting applications. In this study, three types of plasticized PVC in sheet form, with di-(2-ethylhexyl)phthalate (DEHP), tri-(2-ethylhexyl)trimellitate (TEHTM) and n-butyryltri-n-hexyl citrate (BTHC) as plasticizer, were selected for assessment and single solute fibrinogen adsorption was utilized as an initial index of interactions with blood components. Fibrinogen adsorption behavior shows a strong dependence on the plasticizer selection, plasticizer level at the surface and the adsorption conditions, such as adsorption time and fibrinogen solution concentration. Results indicate that BTHC plasticized PVC possesses the lowest adsorption capacity in the three types of plasticized PVC, while TEHTM plasticized PVC seems to have the strongest reactivity in certain fibrinogen solution concentrations. The alteration of surface plasticizer level was achieved by a methanol-cleaning treatment with a variety of cleaning times and the fibrinogen adsorption on plasticized PVC decreases with the reduction of surface plasticizer level. The migration behavior of two phthalate esters (DEHP and TEHTM) was evaluated using UV-Spectrophotometer to determine the plasticizer level at the surfaces. In addition, the fibrinogen adsorption mechanism was examined with Freundlich adsorption modeling.

  18. Track based Alignment of the ATLAS Inner Detector Tracking System

    CERN Document Server

    Schieck, J; The ATLAS collaboration

    2011-01-01

    ATLAS is a multipurpose experiment that records the LHC collisions. In order to reconstruct trajectories of charged particle, ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and microstrips) and drift‐tube detectors. In order to achieve its scientific goals, the ATLAS tracking system requires to determine accurately its almost 700,000 degrees of freedom. The demanded precision for the alignment of the silicon sensors is below 10 micrometers. This implies to use a large sample of high momentum and isolated tracks. The high level trigger selects and stores those tracks in a calibration stream. Tracks from cosmic trigger during empty LHC bunches are also used as input for the alignment. The implementation of the track based alignment within the ATLAS software unifies different alignment approaches and allows the alignment of all tracking subsystems together. Primary vertexing and beam spot constraints have been implemented, as well as constraints on th...

  19. Neurogenomic mechanisms of social plasticity.

    Science.gov (United States)

    Cardoso, Sara D; Teles, Magda C; Oliveira, Rui F

    2015-01-01

    Group-living animals must adjust the expression of their social behaviour to changes in their social environment and to transitions between life-history stages, and this social plasticity can be seen as an adaptive trait that can be under positive selection when changes in the environment outpace the rate of genetic evolutionary change. Here, we propose a conceptual framework for understanding the neuromolecular mechanisms of social plasticity. According to this framework, social plasticity is achieved by rewiring or by biochemically switching nodes of a neural network underlying social behaviour in response to perceived social information. Therefore, at the molecular level, it depends on the social regulation of gene expression, so that different genomic and epigenetic states of this brain network correspond to different behavioural states, and the switches between states are orchestrated by signalling pathways that interface the social environment and the genotype. Different types of social plasticity can be recognized based on the observed patterns of inter- versus intra-individual occurrence, time scale and reversibility. It is proposed that these different types of social plasticity rely on different proximate mechanisms at the physiological, neural and genomic level. © 2015. Published by The Company of Biologists Ltd.

  20. Strain rate dependence in plasticized and un-plasticized PVC

    OpenAIRE

    Siviour C.R.; Kendall M.J.

    2012-01-01

    An experimental and analytical investigation has been made into the mechanical behaviour of two poly (vinyl chloride) (PVC) polymers – an un-plasticized PVC and a diisononyl phthalate (DINP)-plasticized PVC. Measurements of the compressive stress-strain behaviour of the PVCs at strain rates ranging from 10−3 to 103s−1 and temperatures from − 60 to 100∘C are presented. Dynamic Mechanical Analysis was also performed in order to understand the material transitions observed in compression testing...