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Sample records for cobalt self-powered neutron

  1. Self powered neutron detectors

    International Nuclear Information System (INIS)

    Gopalan, C.S.; Ramachandra Rao, M.N.; Ingale, A.D.

    1976-01-01

    Two types of self powered neutron detectors used for in-core flux measurements are described. The characteristics of the various detectors, with emitters Rh, V, Co, Py are presented. Details about the fabrication of these detectors are given. (A.K.)

  2. Self powered neutron detectors

    International Nuclear Information System (INIS)

    Passe, J.; Petitcolas, H.; Verdant, R.

    1975-01-01

    The self-powered neutron detectors (SPND) enable to measure continuously high fluxes of thermal neutrons. They are particularly suitable for power reactor cores because of their robustness. Description of two kinds of SPND's characterized by the electrical current production way is given here: the first SPND's which present a V, Ag or Rh emitter are sensitive enough but they offer a few minute delay time: the second SPND's which are depending on the gamma activation have a short delay time. The emitter is made of Co or Pt. In any case, the signal is linear with reaction rates. Finally, the applications are briefly repeated here: irradiation facility monitor in research reactors, and flux map and space instability control in power reactors [fr

  3. Self-powered neutron detector

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1976-01-01

    A self-powered neutron detector is detailed wherein a thin conductive layer of low neutron cross section, high density material is disposed about an emitter core of material which spontaneously emits radiation on neutron capture. The high density material is absorptive of beta radiation emitted by decay of the emitter core activation product, but is substantially transmissive to the high average energy prompt electrons emitted by the emitter core material. (author)

  4. Measurement with self-powered cobalt and cadmium detectors

    International Nuclear Information System (INIS)

    Azzoni, A.

    The principle of function is described and the characteristics are given of self-powered cobalt and cadmium neutron detectors. Requirements are summed up for the material used for these detectors, and the specific properties of used detectors are given. The calibration of developed self-powered detectors was carried out using the L 54 CESNEF reactor channels with a maximum output of 40 kW and a neutron flux of 10 10 to 10 12 n.cm -2 s -1 . The absolute measurement of neutron flux and gamma radiation doses in the channel were carried out at an output of 10 kW. The objective of calibration measurements with cadmium and cobalt detectors was to ascertain the promptness of detector response, to determine their sensitivity to neutrons and to gamma radiation, the effects of radiation on the material of the detectors and the contribution thereof on the resulting signal. Inside the CART irradiation channel of the ESSOR reactor three such detectors were used for the measurement of neutron flux and its fluctuations effected by coolant density fluctuations. The behaviour of the detectors was studied in a high neutron flux (10 14 n.cm -2 s -1 ) and at long-term irradiation. It was found that cobalt detectors may be used to advantage for measuring the neutron flux if prompt response is required. The high sensitivity to gamma radiation does, however, limit their uses. Cadmium detectors are sensitive to the neutron flux (currents of several mA with a neutron flux of approximately 10 14 n.cm -2 s -1 ) while response to gamma radiation is considerably limited. These detectors are advantageous for short-term use, such as neutron flux mapping and measuring fluctuations. (B.S.)

  5. Measurement of neutron sensitivity of self powered neutron detectors

    International Nuclear Information System (INIS)

    Mahant, A.K.; Yeshuraja, V.; Ghodke, Shobha

    2005-01-01

    Self powered neutron detectors (SPNDs ) will form the part of Reactor Instrumentation in the upcoming 500 MWe power reactors. ECIL has developed Vanadium and Cobalt SPNDs for NPCIL to be used in regulation and protection channels. Experimental determination of neutron sensitivity of the vanadium and cobalt Self Powered Neutron Detectors (SPNDs) was carried out in A-l location of Apsara reactor at BARC. The measurements involved determination of total detector signal, its various components and the thermal neutron flux at the detector location. The paper describes the experimental techniques used to measure various parameters required to evaluate the neutron sensitivity of the SPNDs and also the parameters required to ascertain the integrity of SPNDs. Neutron flux measurement was done by gold foil irradiation technique. The predominant signal component from the vanadium SPND is Ib the current due to activation of the vanadium emitter, it forms about 85% of the total signal. The other components I n,γ due to the capture gamma rays of 52 V and I externalγ produced by the external reactor gamma rays contribute about 10% and 5% respectively to the total signal. Whereas in the cobalt SPND the main signal component is due to the capture gamma rays of 60 Co and accounts for about the 95% of the total signal. Remaining 5% signal is due to external reactor gamma rays. (author)

  6. Self-powered neutron detector

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1974-01-01

    The invention relates a self-powered neutron detector comprising an emitting body, an insulating material surrounding said body, and a conducting outer cover, a power conductor connected to the emitting body and passing through the insulating material permitting to insert an ammeter between said emitting body and said cover. The invention is characterized in that said emitting body is surrounded by a thin conducting layer of small cross section for neutrons made of high density material said material being capable of absorbing the beta-radiations due to the degradation of the emitting body activating product, while transmitting the fast electrons of high average energy emitted by said emitting body. This can be applied to safety control devices required to provide a quick answer [fr

  7. Self-powered in-core detectors of cobalt type

    International Nuclear Information System (INIS)

    Jonsson, Georg

    1975-01-01

    Testing and development of self-powered neutron detectors with a cobalt emitter is described. Long term irradiation at 400 deg C is expected to indicate insulation quality, change in calibration and 60 Co build-up. Dynamic tests to investigate possible transient effects due to temperature changes are being performed on a number of detectors up to about 600 deg C. A long term irradiation at low temperature has been terminated after 4.5 years. On completion, neutron dose was estimated to be 5.6 x 10 21 nvt and the 60 Co background was 9.3 % of the full flux signal. A recently introduced long term test is expected to provide data on instability effects due to 61 Co. For a BWR in-core detector installation, the main advantage of cobalt detectors, apart from the small size, appears to be long life. Development work is being done on detectors with vanadium-cobalt emitters, electronic separation of fast and delayed signals and reduction of gamma sensitivity. (O.T.)

  8. Improved cable compensation technique for self powered neutron detectors

    International Nuclear Information System (INIS)

    Nieuwenhove, R. van

    1996-01-01

    Measurements with cobalt self powered neutron detectors on the BR2 reactor have revealed that the currents induced by external gamma radiation can be of the same order as the neutron induced signal and that the gamma induced current on the emitter and the compensator wires are not symmetric. In this case, the standard detection electronic setup leads to erroneous results. It is shown that a slightly modified electronic setup, in which this asymmetry is compensated for, can nevertheless allow to obtain correct neutron flux measurements. Measures to reduce the influence of external gamma radiation in general will also be discussed. (orig.)

  9. Self-powered neutron flux detector assembly

    International Nuclear Information System (INIS)

    Allan, C.J.; McIntyre, I.L.

    1980-01-01

    A self-powered neutron flux detector has both the central emitter electrode and its surrounding collector electrode made of inconel 600. The lead cables may also be made of inconel. Other nickel alloys, or iron, nickel, titamium, chromium, zirconium or their alloys may also be used for the electrodes

  10. Self-powered neutron flux detector

    International Nuclear Information System (INIS)

    Kroon, J.

    1979-01-01

    A self-powered neutron flux detector having an emitter electrode, at least a major portion of which is, 95 Mo encased in a tubular collector electrode and separated therefrom by dielectric material. The 95 Mo emitter electrode has experimentally shown a 98% prompt response, is primarily sensitive to neutron flux, has adequate sensitivity and has low burn up. Preferably the emitter electrode is molybdenum which has been enriched 75% to 99% by weight with 95 Mo

  11. Construction of a self-powered neutron detector prototype

    International Nuclear Information System (INIS)

    Pombo, J.B.S.M.; Correa, R.F.

    1986-01-01

    Description and testing of a self-powered neutron detector and related current measurement electronics, in construction at Centro de Desenvolviemnto da Tecnologia Nuclear (CDTN), are presented. The cylindrical detector has a 9-wires cobalt emitter, Inconel 600 tubing collector and sinterized alumina electrical insulation. The bifilar signal cable is plugged to the detector through a SHV connector. Preliminary testing has giving information about dielectrical properties of the set and impurities of the materials (by means of activation analysis). The main tests, done in a 100 KW Triga Reactor, allowed the verification of the detector response to the neutron flux, the stability and reproducibility of this response, and also the evaluation of sensitivity to gamma radiation. The detector performance is considered good. (Author) [pt

  12. Design and fabrication of a self-powered neutron detector

    International Nuclear Information System (INIS)

    Garcia Garcia, Florencio.

    1979-01-01

    Self powered neutron detectors are becoming more and more popular in reactor instrumentation. A fast response detector of this type was made at the Reactor Division, La Reina Nuclear Center in Santiago. Cobalt wire was the emitter, teflon the insulator and a stainless steel tubing was the collector. The overall dimensions of the detector are 6 mms diameter and 700 mms length. The irradiation tests, carried out at the Center's 5 Mw research reactor showed a very reasonably linear relation between current supplied by the detector and thermal neutron flux, over a range extending from 10 10 to 10 13 n/cm 2 x seg. These tests also showed a good agreement between calculated and measured current. The models used for the calculation of current are fully explained and they include some improvements over those that have been published recently. An important conclusion for the case of the cobalt detectors is that the wire's diameter must be at least 1 mm. in order to have a neutron induced current bigger than the parasitic components generated by indirect processes. Calculations for other emitters such as vanadium, silver and rhodum are also included. (EC)

  13. Health physics aspects in disposal of self powered neutron detectors

    International Nuclear Information System (INIS)

    Deokar, D.V.; Tibrewala, S.K.; Singh, K.K.; Purohit, R.G.; Tripathi, R.M.

    2014-01-01

    Self Powered Neutron Detectors (SPNDs) are being used in reactor core for neutron flux measurement at Nuclear Power Plants. After their useful life, SPNDs are replaced and are disposed off in Tile holes. The Cobalt SPNDs having activity in the range of 35 to 160 TBq were encompassed in carbon steel canister. The canister having dose 25 to 50 Sv/h at 1 meter were transported in shielded flask for disposal in specially designed Tile hole at Solid Waste Management Facility (SWMF) at Tarapur. To keep personal exposures As Low As Reasonably Achievable (ALARA) the disposal operation was carried out remotely from a shielded cabin placed at a distance of 50 meter from the disposal site. During the disposal radiation measurements were carried out remotely by installing radiations monitors at a distance of 10 m, 25 m, and 50 m from the Tile hole. Estimations of radiation levels were carried out before jobs were taken up. Disposal of 70 numbers of Cobalt SPNDs was carried out by implementing ALARA. The decrease in collective dose is achieved due to improved operational practices, mock-up trials, effective monitoring program and safety compliance at various stages of operation

  14. Self-Powered Neutron and Gamma Detectors for In-Core Measurements

    International Nuclear Information System (INIS)

    Strindehag, O.

    1971-11-01

    The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

  15. Self-Powered Neutron and Gamma Detectors for In-Core Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O

    1971-11-15

    The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

  16. Transient response of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Boeck, H.; Gebureck, P.; Stegemann, D.

    The behaviour of self-powered neutron detectors with Co, Er, Hf and Pt emitters was investigated during reactor square wave and pulse operation. The detector's response was compared with the current of an excore ionization chamber. Characteristical deviations from linearity were observed with all detectors at fast reactor periods. The exact cause of these deviations is not yet fully understood but several possibilities for the nonlinear behaviour of self-powered neutron detectors are outlined. (author)

  17. Neutron sensitivity of prompt-response self-powered neutron detectors and the interval rule

    International Nuclear Information System (INIS)

    Molina Avila, J.; Carmolopes, M.

    1989-01-01

    This paper is devoted to the calculation of thermal s th and epithermal s epi sensitivities of cobalt prompt-response Self-Powered Neutron Detectors (SPNDs). The thermal sensitivity was obtained for a Maxwellian neutron field, and the effect of scattering on the self-shielding correction was taken into consideration in the second-collision approximation. The dependence of s th on the emitter radius R was studied in a wide region of R (0.025 to 0.2 cm). The differential and global epithermal sensitivities were calculated using a simple expression for the first-collision neutron absorption probability. Finally, a criterion to evaluate the accuracy of the parameters of the model was established in the form of some Interval Rule which is very sensitive to the radial dependence of the flux perturbation correction and other parameters of the model in both the thermal and epithermal regions

  18. In-reactor testing of self-powered neutron detectors and miniature fission chambers

    International Nuclear Information System (INIS)

    Duchene, J.; LeMeur, R.; Verdant, R.

    1975-01-01

    The CEA has tested a variety of ''slow'' self-powered neutron detectors with rhodium, silver and vanadium emitters. Currently there are 120 vanadium detectors in the EL4 heavy water reactor. In addition, ''fast'' detectors with cobalt emitters have been tested at Saclay and 50 of these are in reactor. Other studies are concerned with 6 mm diameter miniature fission chambers. Two fast response chambers with argon-nitrogen filling gas became slow during irradiation, but operated to 600 deg C. An argon filled chamber of 4.7 mm diameter, for traversing in core system in pressurized water reactor, has shown satisfactory test results. (author)

  19. Self-powered neutron detector of high sensitivity

    International Nuclear Information System (INIS)

    Brixy, H.; Spillekothen, H.G.; Benninghofen, G.; Serafin, N.

    1983-01-01

    A self-powered neutron detector is proposed, consisting of three concentrically arranged electrically conducting tubes; where the central one forms the emitter and the inner and outer ones form the collector and where the tubes are electrically insulated from each other by insulating material. The emitter consists of a material with a high absorption cross-section for thermal neutrons, particularly of gadolinium, and is provided with an auxiliary emitter layer on the inside or the outside. With suitable dimensions and material, the auxiliary emitter layer increases the yield of electrons. (orig./HP) [de

  20. Self-powered neutron and gamma-ray flux detector

    International Nuclear Information System (INIS)

    Allan, C.J.; Shields, R.B.; Lynch, G.F.; Cuttler, J.M.

    1980-01-01

    A new type of self-powered neutron detector was developed which is sensitive to both the neutron and gamma-ray fluxes. The emitter comprises two parts. The central emitter core is made of materials that generate high-energy electrons on exposure to neutrons. The outer layer acts as a gamma-ray/electron converter, and since it has a higher atomic number and higher back-scattering coefficient than the collector, increases the net outflow or emmission of electrons. The collector, which is around the emitter outer layer, is insulated from the outer layer electrically with dielectric insulation formed from compressed metal-oxide powder. The fraction of electrons given off by the emitter that is reflected back by the collector is less than the fraction of electrons emitted by the collector that is reflected back by the emitter. The thickness of the outer layer needed to achieve this result is very small. A detector of this design responds to external reactor gamma-rays as well as to neutron capture gamma-rays from the collector. The emitter core is either nickel, iron or titanium, or alloys based on these metals. The outer layer is made of platinum, tantalum, osmium, molybdenum or cerium. The detector is particularly useful for monitoring neutron and gamma ray flux intensities in nuclear reactor cores in which the neutron and gamma ray flux intensities are closely proportional, are unltimately related to the fission rate, and are used as measurements of nuclear reactor power. (DN)

  1. Kalman filtering of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Kantrowitz, M.L.

    1992-01-01

    Pressurized water reactors employ a wide variety of in-core detectors to determine the neutronic behavior within the core. Among the detectors used are rhodium and vanadium self-powered detectors (SPDs), which are very accurate, but respond slowly to changes in neutron flux. This paper describes a new dynamic compensation algorithm, based on Kalman filtering, which converts delayed-responding rhodium and vanadium SPDs into prompt-responding detectors by reconstructing the dynamic flux signal sensed by the detectors from the prompt and delayed components. This conversion offers the possibility of utilizing current fixed in-core detector systems based on these delayed-responding detectors for core control and/or core protection functions without the need for fixed in-core detectors which are prompt-responding. As a result, the capabilities of current fixed in-core detector systems could be expanded significantly without a major hardware investment

  2. Kalman filtering for rhodium self-powered neutron detectors

    International Nuclear Information System (INIS)

    Kantrowitz, M.L.

    1988-01-01

    Rhodium self-powered neutron detectors are utilized in many pressurized water reactors to determine the neutronic behavior within the core. In order to compensate for the inherent time delay associated with the response of these detectors, a dynamic compensation algorithm is currently used in Combustion Engineering plants to reconstruct the dynamic flux signal which is being sensed by the rhodium detectors. This paper describes a new dynamic compensation algorithm, based on Kalman filtering, which improves on the noise gain and response time characteristics of the algorithm currently used, and offers the possibility of utilizing the proven rhodium detector based fixed in-core detector system as an integral part of advanced core control and/or protection systems

  3. Sensitivity Calculation of Vanadium Self-Powered Neutron Detector

    International Nuclear Information System (INIS)

    Cha, Kyoon Ho

    2011-01-01

    Self-powered neutron detector (SPND) is being widely used to monitor the reactor core of the nuclear power plants. The SPND contains a neutron-sensitive metallic emitter surrounded by a ceramic insulator. Currently, the rhodium SPND has been used in many nuclear power plants. The lifetime of rhodium is too short (about 3∼5 years) to operate the nuclear power plant economically. The vanadium (V) SPND is also primarily sensitive to neutrons like rhodium, but is a somewhat slower reaction time as that of a rhodium SPND. The benefit of vanadium over rhodium is its low depletion rate, which is a factor of 7 times less than that of rhodium. For this reason, a vanadium SPND has been being developed to replace the rhodium SPND which is used in OPR1000. Some Monte Carlo simulations were accomplished to calculate the initial sensitivity of vanadium emitter material and alumina (Al 2 O 3 ) insulator with a cylindrical geometry. An MCNP-X code was used to simulate some factors (neutron self shielding factor and electron escape probability from the emitter) necessary to calculate the sensitivity of vanadium detector. The simulation results were compared with some theoretical and experimental values. The method presented here can be used to analyze the optimum design of the vanadium SPND

  4. Development of an inconel self powered neutron detector for in-core reactor monitoring

    Science.gov (United States)

    Alex, M.; Ghodgaonkar, M. D.

    2007-04-01

    The paper describes the development and testing of an Inconel600 (2 mm diameter×21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the 60Co irradiation facility in 14 MR/h gamma field showed values of -4.4×10 -18 A/R/h/cm (-9.3×10 -24 A/ γ/cm 2-s/cm), -5.2×10 -18 A/R/h/cm (-1.133×10 -23 A/ γ/cm 2-s/cm) and 34×10 -18 A/R/h/cm (7.14×10 -23 A/ γ/cm 2-s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6×10 -23 A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69×10 -22 and 2.64×10 -22 A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within ±5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress.

  5. Development of an inconel self powered neutron detector for in-core reactor monitoring

    International Nuclear Information System (INIS)

    Alex, M.; Ghodgaonkar, M.D.

    2007-01-01

    The paper describes the development and testing of an Inconel600 (2 mm diameterx21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the 60 Co irradiation facility in 14 MR/h gamma field showed values of -4.4x10 -18 A/R/h/cm (-9.3x10 -24 A/γ/cm 2 -s/cm), -5.2x10 -18 A/R/h/cm (-1.133x10 -23 A/γ/cm 2 -s/cm) and 34x10 -18 A/R/h/cm (7.14x10 -23 A/γ/cm 2 -s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6x10 -23 A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69x10 -22 and 2.64x10 -22 A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within ±5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress

  6. Development of an inconel self powered neutron detector for in-core reactor monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Alex, M. [Electronics Division, BARC, Mumbai (India)]. E-mail: maryalex@barc.gov.in; Ghodgaonkar, M.D. [Electronics Division, BARC, Mumbai (India)

    2007-04-21

    The paper describes the development and testing of an Inconel600 (2 mm diameterx21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the {sup 60}Co irradiation facility in 14 MR/h gamma field showed values of -4.4x10{sup -18} A/R/h/cm (-9.3x10{sup -24} A/{gamma}/cm{sup 2}-s/cm), -5.2x10{sup -18} A/R/h/cm (-1.133x10{sup -23} A/{gamma}/cm{sup 2}-s/cm) and 34x10{sup -18} A/R/h/cm (7.14x10{sup -23} A/{gamma}/cm{sup 2}-s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6x10{sup -23} A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69x10{sup -22} and 2.64x10{sup -22} A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within {+-}5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress.

  7. The determination of self-powered neutron detector sensitivity on thermal and epithermal neutron flux densities

    International Nuclear Information System (INIS)

    Erben, O.

    1980-01-01

    The coefficients of thermal and epithermal neutron flux density depression and self-shielding for the SPN detectors with vanadium, rhodium, silver and cobalt emitters are presented, (for cobalt SPN detectors the functions describing the absorbtion of neutrons along the emitter cross-section are also shown). Using these coefficients and previously published beta particle escape efficiencies, sensitivities are determined for the principal types of detectors produced by Les Cables de Lyon and SODERN companies. The experiments and their results verifying the validity of the theoretical work are described. (author)

  8. Self-powered neutron and γ-ray flux detector

    International Nuclear Information System (INIS)

    Allan, C.J.

    1983-01-01

    According to the invention there is provided a self-powered neutron and γ-ray flux detector, comprising: a) an emitter core wire; b) an emitter outer layer around the core wire and of different metal thereto; c) a metal collector around the emitter core wire and the emitter outer layer; and d) dielectric insulation electrically insulating the emitter core wire and the emitter outer layer from the metal collector. The improvement comprises: a) the overall diameter of the emitter core wire and the emitter outer layer is at least of the order of 0.4 mm in diameter; b) the emitter outer layer covers only of the order of l0 percent of the order of 90 percent of the emitter core wire surface area and comprises at least one band around the emitter core wire and is of a thickness in the range of the order 0.02 mm to of the order of 0.07 mm; and c) the metal of the emitter core wire, the metal of the emitter outer layer, the metal of the metal collector, the overall diameter of the emitter core wire and the emitter outer layer and the surface area of the emitter core wire that is covered by the emitter outer layer are selected so that the detector has a prompt fraction in the range of the order of 90 percent to of the order of 96 percent and has a dynamic response which substantially matches the dynamic response of the power in the fuel of the nuclear reactor in which the detector is to be used

  9. In-core neutron flux measurements at PARR using self powered neutron detector

    International Nuclear Information System (INIS)

    Hussain, A.; Ansari, S.A.

    1989-10-01

    This report describes experimental reactor physics measure ments at PARR using the in-core neutron detectors. Rhodium self powered neutron detectors (SPND) were used in the PARR core and several measurements were made aimed at detector calibration, response time determination and neutron flux measurements. The detectors were calibrated at low power using gold foils and full power by the thermal channel. Based on this calibration it was observed that the detector response remains almost linear throughout the power range. The self powered detectors were used for on-line determination of absolute neutron flux in the core as well as the spatial distribution of neutron flux or reactor power. The experimental, axial and horizontal flux mapping results at certain locations in the core are presented. The total response time of rhodium detector was experimentally determined to be about 5 minutes, which agree well with the theoretical results. Because of longer response time of SPND of the detectors it is not possible to use them in the reactor protection system. (author). 10 figs

  10. Characterization of hybrid self-powered neutron detector under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamichi, M. E-mail: masaru@oarai.jaeri.go.jp; Nagao, Y.; Yamamura, C.; Nakazawa, M.; Kawamura, H

    2000-11-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%R000.

  11. Characterization of hybrid self-powered neutron detector under neutron irradiation

    CERN Document Server

    Nakamichi, M; Yamamura, C; Nakazawa, M; Kawamura, H

    2000-01-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%Rh.

  12. Radiological safety aspects associated with the handling, storage and disposal of self power neutron detectors in TAPS - 3 and 4

    International Nuclear Information System (INIS)

    Parida, B.K.; Mudgal, B.; Ghadigoankar, V.R.; Niraj; Ashok; Pati, C.K.; Patil, P.M.; Pawar, S.K.; Varadhan, R.S.

    2006-01-01

    At Tarapur Atomic Power Station 3 and 4, 540 MWe Pressurised Heavy Water Reactors, core being large in size requires a continuous in core monitoring for local flux disturbances. Nearly 200 Self Powered Neutron Detectors (SPNDs) of the Straight Individually Replaceable (SIR) type are distributed in the reactor core. For purpose of reactor regulation and protection, cobalt SPNDs that have a prompt response for changes in power is used for in-core flux mapping, vanadium SPNDs that provide accurate measure of neutron flux, even though having slow response is used In core SPNDs are placed in Vertical Flux Units (VFU) and Horizontal Flux Units (HFUs). These SPNDs were to be replaced at regular intervals to meet the design intent. Cobalt SPNDs have dose rates of the order of 1000 Gy/h and the Mineral Insulated (MI) cables of Vanadium SPNDs have dose rates of the order of 100 Gy/h. So far 3 Cobalt SPNDs were removed from HFUs and are being stored in lead shielding inside spent fuel storage facility. These high active components were handled with meticulous planning with lowest exposures to the maintainers. Radiological safety aspects of handling and storage of SPNDs are discussed in this report. (author)

  13. Real time neutron flux monitoring using Rh self powered neutron detector

    International Nuclear Information System (INIS)

    Juna, Byung Jin; Lee, Byung Chul; Park, Sang Jun; Jung, Hoan Sung

    2012-01-01

    Rhodium (Rh) self powered neutron detectors (SPNDs) are widely used for on line monitoring of local neutron flux. Its signal is slower than the actual variation of neutron flux owing to a delayed β decay of the Rh activation product, but real time monitoring is possible by solving equations between the neutron reaction rate in the detector and its signal. While the measuring system is highly reliable, the accuracy depends on the method solving the equations and accuracy of the parameters in the equations. The uncertain parameters are the contribution of gamma rays to the signal, and the branching ratios of Rh 104 and Rh 104m after the neutron absorption of Rh 103. Real time neutron flux monitoring using Rh SPNDs has been quite successful for neutron transmutation doping (NTD) at HANARO. We revisited the initial data used for the verification of a real time monitoring system, to refine algorithm for a better solution and to check the parameters for correctness. As a result, we suggest an effective way to determine the prompt parameter

  14. Real time neutron flux monitoring using Rh self powered neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Juna, Byung Jin; Lee, Byung Chul; Park, Sang Jun; Jung, Hoan Sung [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    Rhodium (Rh) self powered neutron detectors (SPNDs) are widely used for on line monitoring of local neutron flux. Its signal is slower than the actual variation of neutron flux owing to a delayed {beta} decay of the Rh activation product, but real time monitoring is possible by solving equations between the neutron reaction rate in the detector and its signal. While the measuring system is highly reliable, the accuracy depends on the method solving the equations and accuracy of the parameters in the equations. The uncertain parameters are the contribution of gamma rays to the signal, and the branching ratios of Rh 104 and Rh 104m after the neutron absorption of Rh 103. Real time neutron flux monitoring using Rh SPNDs has been quite successful for neutron transmutation doping (NTD) at HANARO. We revisited the initial data used for the verification of a real time monitoring system, to refine algorithm for a better solution and to check the parameters for correctness. As a result, we suggest an effective way to determine the prompt parameter.

  15. Self-powered in-core neutron detector assembly with uniform perturbation characteristics

    International Nuclear Information System (INIS)

    Todt, W.H.; Playfoot, K.C.

    1979-01-01

    Disclosed is a self-powered in-core neutron detector assembly in which a plurality of longitudinally extending self-powered detectors have neutron responsive active portions spaced along a longitudinal path. A low neutron absorptive extension extends from the active portions of the spaced active portions of the detectors in symmetrical longitudinal relationship with the spaced active detector portions of each succeeding detector. The detector extension terminates with the detector assembly to provide a uniform perturbation characteristic over the entire assembly length

  16. Initial absolute calibration factors for some neutron sensitive self-powered detectors

    International Nuclear Information System (INIS)

    Kroon, J.

    1975-01-01

    Self-powered flux detectors have found extensive use as monitoring devices in PWR (Pressurized Water Reactor) cores and CANDU (Canada Deuterium Uranium) type power reactors. The detectors measure fuel power distributions and indicate trip parameters for reactor control and safety requirements. Both applications demand accurate absolute initial calibration factors. Experimental results obtained in calibrating some neutron sensitive self-powered detectors is presented. (author)

  17. Characteristics of self-powered neutron detectors used in power reactors

    International Nuclear Information System (INIS)

    Todt, William H. Sr.

    1998-01-01

    Self-powered neutron detectors have been used effectively as in-core flux monitors for over twenty-five years in nuclear power reactors worldwide. This paper describes the basic properties of these radiation sensors including their nuclear, electrical and mechanical characteristics. Recommendations are given for the proper choice of the self-powered detector emitter to provide the proper response time and radiation sensitivity desired for use in an effective in-core radiation monitoring system. Examples are shown of specific self-powered detector designs, which are being effectively, used in in-core instrumentation systems for pressurized water, heavy water and graphite moderated light water reactors. Also examples are shown of the mechanical configurations of in-core assemblies of self-powered detectors combined with in-core thermocouples presently used in pressurized water and heavy water reactors worldwide. (author)

  18. Investigation of the response of improved self-powered neutron detectors

    International Nuclear Information System (INIS)

    Erk, S.

    1982-01-01

    The self-powered neutron detectors have been successfully employed for the most important parameters both for neutron flux and flux fluence determination. Their preference for such measurements due to their simplicity, convenience in use, rigidity, voluminal smallness and low price. However, self-powered neutron detectors depend on the type used, can only follow the neutron flux changes with a certain delay when they are compared to fission chambers which are thought to be the best detectors. In this thesis, a system has been proposed and considered carefully in order to speed up the response time, in another word, to correct the detector response to a level very near to fission chamber performance, a circuitry has been realized in the frame of principles so forth and applied to the experiments carried out in the TR-1 Reactor. Their positive results are presented. (author)

  19. Self-powered in-core neutron detector assembly with uniform perturbation characteristics

    International Nuclear Information System (INIS)

    1981-01-01

    An in-core neutron detector assembly consisting of a number of longitudinally extending self-powered detectors is described. The uniform mechanical structures and materials are placed symmetrically at each active detector portion thus ensuring that local perturbation factors are uniform. (U.K.)

  20. Use of FET in automatic scanning of measurements using thermocouples and self-powered neutron detectors

    International Nuclear Information System (INIS)

    Plaige, Yves.

    1977-01-01

    Advantages lying in using FET switches in the relays of multiplexing systems are shown with two examples of application. Their performance as regard fast reliable operation are used in temperature measurement scanning inside nuclear reactors. As for current measurements using self-powered neutron detectors, the weak leakage currents of said switches ( [fr

  1. Burnup Estimation of Rhodium Self-Powered Neutron Detector Emitter in VVER Reactor Core Using Monte Carlo Simulations

    OpenAIRE

    Khrutchinsky, А. А.; Kuten, S. A.; Babichev, L. F.

    2011-01-01

    Estimation of burn-up in a rhodium-103 emitter of self-powered neutron detector in VVER-1000 reactor core has been performed using Monte Carlo simulations within approximation of a constant neutron flux.

  2. Comparison of dynamic compensation methods for delayed self-powered neutron detector

    International Nuclear Information System (INIS)

    In, Wang Kee; Kim, Joon Sung; Auh, Geun Sun; Yoon, Tae Young

    1993-01-01

    Dynamic compensation methods for rhodium self-powered neutron detector have been developed by Banda and Hoppe to compensate for the time delay associated with detector signals. The time delay is due to the decay of the neutron-activated rhodium and results in delayed detector response. Two digital dynamic compensation methods, were compared for step change of neutron flux in this paper. The inverse kinetics method gave slightly better response time and noise gain. However, the inverse kinetics method also showed overshooting of neutron flux for the step change. (Author)

  3. Dynamical model of computation of the rhodium self-powered neutron detector current

    International Nuclear Information System (INIS)

    Erben, O.; Slovacek, M.; Zerola, L.

    1992-01-01

    A model is presented for the calculation of the rhodium self-powered neutron detector current in dependence on the neutron flux density during reactor core transients. The total signal consists of a beta emission, prompt, and gamma component and a background signal. The model has been verified by means of experimental data obtained during measurements on the LVR-15 research reactor and at the Dukovany nuclear power plant. (author) 9 figs., 21 refs

  4. Analysis of the sensitivity concept of self-powered neutron detector (SPND)

    International Nuclear Information System (INIS)

    Moreira, O.; Lescano, H.

    2012-01-01

    Self powered neutron detectors (SPND) are widely used to monitor the neutron flux, either in nuclear as in irradiation facilities and medical treatments. However, the physical meaning of the parameter that is used to relate the detector signal (an electrical current) with the neutron flux, i.e., the sensitivity of the detector, has not been sufficiently analyzed. Since the definition of sensitivity, ε=i/φ is calculated for particular reactor conditions, i.e., for thermal neutrons at room temperature, it does not take into account the deviation originated from other conditions of temperature (above ambient), as found for example in nuclear power plants. In this work we calculated the microscopic cross section weighted with the neutron flux, defined in the usual way. This weighted microscopic cross section reveals the no proportionality between the absorption rate and the neutron flux, exhibiting the problem that the SPND current signal has to properly represent the neutron flux (author)

  5. Development of self-powered neutron detectors for neutron flux monitoring in HCLL and HCPB ITER-TBM

    International Nuclear Information System (INIS)

    Angelone, M.; Klix, A.; Pillon, M.; Batistoni, P.; Fischer, U.; Santagata, A.

    2014-01-01

    Highlights: •Self powered neutron detector (SPND) is attractive neutron monitor for TBM in ITER. •In hard neutron spectra (e.g. TBM) there is the need to optimize their response. •Three state-of-the-art SPNDs were tested using fast and 14 MeV neutrons. •The response of SPNDs is much lower than in thermal neutron flux. •FISPACT calculations performed to find out candidate materials in hard spectra. -- Abstract: Self powered neutron detectors (SPND) have a number of interesting properties (e.g. small dimensions, capability to operate in harsh environments, absence of external bias), so they are attractive neutron monitors for TBM in ITER. However, commercially available SPNDs are optimized for operation in a thermal nuclear reactor where the neutron spectrum is much softer than that expected in a TBM. This fact can limit the use of SPND in a TBM since the effective cross sections for the production of beta emitters are much lower in a fast neutron spectrum. This work represents the first attempt to study SPNDs as neutron flux monitors for TBM. Three state-of-the-art SPND available on the market were bought and tested using fast neutrons at TAPIRO fast neutron source of ENEA Casaccia and with 14 MeV neutrons at the Frascati neutron generator (FNG). The results clearly indicate that in fast neutron spectra, the response of SPNDs is much lower than in thermal neutron flux. Activation calculations were performed using the FISPACT code to find out possible material candidates for SPND suitable for operation in TBM neutron spectra

  6. Development of self-powered neutron detectors for neutron flux monitoring in HCLL and HCPB ITER-TBM

    Energy Technology Data Exchange (ETDEWEB)

    Angelone, M., E-mail: maurizio.angelone@enea.it [Associazione ENEA-EURATOM sulla FusioneENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Klix, A. [Association KIT-EURATOM, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pillon, M.; Batistoni, P. [Associazione ENEA-EURATOM sulla FusioneENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Fischer, U. [Association KIT-EURATOM, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Santagata, A. [ENEA C.R. Casaccia, via Anguillarese Km. 1,300, 00100 Roma (Italy)

    2014-10-15

    Highlights: •Self powered neutron detector (SPND) is attractive neutron monitor for TBM in ITER. •In hard neutron spectra (e.g. TBM) there is the need to optimize their response. •Three state-of-the-art SPNDs were tested using fast and 14 MeV neutrons. •The response of SPNDs is much lower than in thermal neutron flux. •FISPACT calculations performed to find out candidate materials in hard spectra. -- Abstract: Self powered neutron detectors (SPND) have a number of interesting properties (e.g. small dimensions, capability to operate in harsh environments, absence of external bias), so they are attractive neutron monitors for TBM in ITER. However, commercially available SPNDs are optimized for operation in a thermal nuclear reactor where the neutron spectrum is much softer than that expected in a TBM. This fact can limit the use of SPND in a TBM since the effective cross sections for the production of beta emitters are much lower in a fast neutron spectrum. This work represents the first attempt to study SPNDs as neutron flux monitors for TBM. Three state-of-the-art SPND available on the market were bought and tested using fast neutrons at TAPIRO fast neutron source of ENEA Casaccia and with 14 MeV neutrons at the Frascati neutron generator (FNG). The results clearly indicate that in fast neutron spectra, the response of SPNDs is much lower than in thermal neutron flux. Activation calculations were performed using the FISPACT code to find out possible material candidates for SPND suitable for operation in TBM neutron spectra.

  7. Characteristics of self-powered neutron detectors used in power reactors

    International Nuclear Information System (INIS)

    Todt, W.H.

    1997-01-01

    Self-Powered Neutron Detectors have been used effectively as in-core flux monitors for over twenty-five years in nuclear power reactors world-wide. The basic properties of these radiation sensors are described including their nuclear, electrical and mechanical characteristics. Recommendations are given for the proper choice of the self-powered detector emitter to provide the proper response time and radiation sensitivity desired for use in an effective in-core radiation monitoring system. Examples are shown of specific self-powered detector designs which are being effectively used in in-core instrumentation systems for pressurised water, heavy water and graphite moderated light water reactors. Examples are also shown of the mechanical configurations of in-core assemblies of self-powered detectors combined with in-core thermocouples presently used in pressurised water and heavy water reactors worldwide. This paper is a summary of a new IEC standard to be issued in 1996 describing the characteristics and test methods of self-powered detectors used in nuclear power reactors. (author)

  8. Development of measuring system with self-powered neutron detectors for the LR-0 reactor

    International Nuclear Information System (INIS)

    Erben, O.; Horinek, K.; Szasz, Z.

    1989-01-01

    A measuring channel with self-powered detectors was developed for measuring neutron fluxs density in the reactor core. The measuring channel consists of a measuring probe with standard self-powered detectors of Soviet make, a signal pathway, a current/voltage converter and a measuring and recording unit. Neutron flux density in the LR-0 reactor core reaches a maximum of 10 13 m -2 s -1 . Experiments using the channel were carried out both in steady-state operation and after emergency shutdown of the reactor, this from power levels of 2,096 W and 1,830 W. The results of the experiments are tabulated and briefly analyzed. (Z.M.). 4 figs., 3 tabs., 5 refs

  9. Design, construction and testing of a self-powered neutron detector

    International Nuclear Information System (INIS)

    Correa, R.F.

    1987-01-01

    The design, construction and testing of a self-powered neutron detector (SPN) and associated electronics are described. Several tests were performed giving information about dielectrical properties of detector and cable, gamma spectra induced in the detector through reactor irradiation, detector response as a function of neutron flux, current stability and reproductibility with the neutron flux. The gamma and neutron sensitivities were also evaluated, by means of thermoluminescent dosimeters and gold foils as references. The test results are presented and show that the detector response is reliable. The gamma and neutron sensitivities are in agreement with those found in the available literature. Nevertheless, a ceramic insulated cable should be employed for permanent use in a reactor. The tests were performed in a 100 KW TRIGA Mark I reactor at the Centro de Desenvolvimento da Tecnologia Nuclear of NUCLEBRAS, in Belo Horizonte, Brazil. (author) [pt

  10. Design constrution and testing of a self-powered neutron detector

    International Nuclear Information System (INIS)

    Correa, R.F.

    1987-01-01

    The design, contruction and testing of a self-powered neutron detector (SPN) and associated electronics are described. Several tests were performed giving information about dielectrical properties od detector and cable, gamma spectra induced in the detector through reactor irradiation, detector response as a function of neutron flux, current stability and reproductibility with the neutron flux. The gamma and neutron sensitivities were also evaluated, by means of thermoluminescent dosimeters and gold foils as references. The test results are presented and show that the detector response is reliable. The gamma and neutron sensitivities are in agreement with those found in the available literature. Neverthe less, a ceramic insulated cable should be employed for permanent use in a reactor. The tests were perfomance in a 100 kW TRIGA Mark I reactor at the Centro de Desenvolvimento da Tecnologia Nuclear of NUCLEBRAS,in Belo Horizonte, Brazil. (Author) [pt

  11. Industrial development of neutron detectors, fission chambers, self powered detectors, ionization chambers

    International Nuclear Information System (INIS)

    Constans, H.; Coville, P.; Guerre, J.

    1975-01-01

    Reactor control requires the determination of neutron flux at all times. The needed characteristics lead to use of several types of detectors: boron lined counters, boron lined ionization chambers, fission ionization chambers and self powered detectors. The principle of the reaction involved the fabrication requirements, the different modes of utilization and the characteristics obtained are examined for each detector. The problem of electric connections in the active area has been solved by developing ''integrated cables'' [fr

  12. Self-Powered Neutron Detector Calibration Using a Large Vertical Irradiation Hole of HANARO

    OpenAIRE

    Kim Myong-Seop; Park Byung-Gun; Kang Gi-Doo

    2018-01-01

    A calibration technology of the self-powered neutron detectors (SPNDs) using a large vertical irradiation hole of HANARO is developed. The 40 Rh-SPNDs are installed on the polycarbonate plastic support, and the gold wires with the same length as the effective length of the rhodium emitter of the SPND are also installed to measure the neutron flux on the SPND. They are irradiated at a low reactor power, and the SPND current is measured using the pico-ammeter. The external gamma-rays which affe...

  13. An investigation of models of rhodium emitter used in self-powered neutron detector

    International Nuclear Information System (INIS)

    Borisenko, V.I.; Piontkovskij, Yu.F.; Goranchuk, V.V.

    2017-01-01

    he paper presents the results of MCNP simulation of the self-powered neutron detector (SPND) signal formation as a result of emitter nuclei activation under the irradiation with neutrons generated in the fuel assemblies. To account for the non-uniformity of emitter burnup along the radius, its model was divided radially into 10 layers of equal thickness. It has been shown that the main contribution of about 88 % of SPND signal is provided by the four peripheral emitter layers. The contribution of different parts of emitter to the SPND signal formation throughout the lifetime of the SPND in the In-Core Monitoring System was found. Simulation results allow us to determine the SPND signal when the spectral characteristics of the neutron flux at the detector location change during the fuel campaign. The study has investigated and proposed a SPND model with the higher neutron sensitivity even though a smaller amount of expensive rhodium is used.

  14. A study on the sensitivity depletion laws for rhodium self-powered neutron detectors

    International Nuclear Information System (INIS)

    Kim, Gil Gon

    1999-02-01

    The rhodium self-powered neutron detectors (SPND) in a reactor core provide the operator with the on-line 3-dimensional nuclear power distribution. The signal produced by rhodium SPND is interpreted into the local neutron flux by using a sensitivity depletion law and the local neutron flux is interpreted into the local power by using a power conversion factor. This work on the sensitivity depletion laws for rhodium self-powered neutron detectors (SPND) is performed to improve the uncertainty of the sensitivity depletion law used in ABB-CE reactors employing a rhodium SPND and to develop a calculational tool for providing the sensitivity depletion laws to interpret the signal of the newly designed rhodium SPND into the local neutron flux. The calculational tools for a time dependent neutron flux distribution in the rhodium emitter during depletion and for a time dependent beta escape probability that a beta generated in the emitter is escaped into the collector were developed. Due to the cost, the exposure to the radiation, and the longer fuel cycle, there is a strong incentive that the loading density of an in-core instrumentation is reduced and the lifetime of the detector is lengthened. These objectives can be achieved by reducing the uncertainty which is amplified as it depletes. The calculational tools above provide the sensitivity depletion law and show the reduction of the uncertainty to about 1 % in interpreting the signal into the local neutron flux compared to the method employed by ABB-CE. The reduction in the uncertainty of 1 % in interpreting the signal into the local neutron flux is equivalent to the reduction in the uncertainty of 1 % or more in interpreting the signal into the local power and to the extension of the lifetime of rhodium SPND to about 10 % as reported by ABB-CE

  15. Robust filtering for dynamic compensation of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Peng, Xingjie; Li, Qing; Zhao, Wenbo; Gong, Helin; Wang, Kan

    2014-01-01

    Highlights: • Three dynamic compensation methods based on robust filtering theory are proposed. • Filter design problems are converted into linear matrix inequality problems. • Rhodium and Vanadium self-powered neutron detectors are used to validate the use of these three dynamic compensation methods. • The numerical simulation results show that all three methods can provide a reasonable balance between response speed and noise suppression. - Abstract: Self-powered neutron detectors (SPNDs), which are widely used in nuclear reactors to obtain core neutron flux distribution, are accurate at steady state but respond slowly to changes in neutron flux. Dynamic compensation methods are required to improve the response speed of the SPNDs and make it possible to apply the SPNDs for core monitoring and surveillance. In this paper, three digital dynamic compensation methods are proposed. All the three methods are based on the convex optimization framework using linear matrix inequalities (LMIs). The simulation results show that all three methods can provide a reasonable balance between response speed and noise suppression

  16. Feasibility study of Self Powered Neutron Detectors in Fast Reactors for detecting local change in neutron flux distribution

    International Nuclear Information System (INIS)

    Jammes, Christian; Filliatre, Philippe; Verma, Vasudha; Hellesen, Carl; Jacobsson Svard, Staffan

    2015-01-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor system. Diverse possibilities of detector systems installation have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local change in neutron flux distribution. We show that the gamma contribution from fission products decay in the fuel and activation of structural materials is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occurring inside the reactor core. (authors)

  17. Feasibility study of Self Powered Neutron Detectors in Fast Reactors for detecting local change in neutron flux distribution

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, Christian; Filliatre, Philippe [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St Paul-Lez-Durance, (France); Verma, Vasudha; Hellesen, Carl; Jacobsson Svard, Staffan [Division of Applied Nuclear Physics, Uppsala University, SE-75120 Uppsala, (Sweden)

    2015-07-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor system. Diverse possibilities of detector systems installation have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local change in neutron flux distribution. We show that the gamma contribution from fission products decay in the fuel and activation of structural materials is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occurring inside the reactor core. (authors)

  18. Use of self powered neutron detectors in the IEA-R1 reactor

    International Nuclear Information System (INIS)

    Galo Rocha, F. del.

    1989-01-01

    A survey of self-powered neutron detectors, SPND, which are used as part of the in-core instrumentation of nuclear reactors is presented. Measurements with Co and Er SPND's were made in the IEA-R1 reactor for determining the neutron flux distribution and the integral reactor power. Due to the size of the available detectors, the neutron flux distribution could not be obtained with accuracy. The results obtained in the reactor power measurements demonstrate that the SPND have the linearity and the quick response necessary for a reactor power channel. This work also presents a proposed design of a SPND using Pt as wire emissor. This proposed design is based in the experience gained in building two prototypes. The greatest difficulties encountered include materials and technology to perform the delicate weldings. (author)

  19. Application of nuclear pumped laser to an optical self-powered neutron detector

    Science.gov (United States)

    Yamanaka, N.; Takahashi, H.; Iguchi, T.; Nakazawa, M.; Kakuta, T.; Yamagishi, H.; Katagiri, M.

    1996-05-01

    A Nuclear Pumped Laser (NPL) using 3He/Ne/Ar gas mixture is investigated for a purpose of applying to an optical self-powered neutron detector. Reactor experiments and simulations on lasing mechanism have been made to estimate the best gas pressure and mixture ratios on the threshold input power density (or thermal neutron flux) in 3He/Ne/Ar mixture. Calculational results show that the best mixture pressure is 3He/Ne/Ar=2280/60/100 Torr and thermal neutron flux threshold 5×1012 n/cm2 sec, while the reactor experiments made in the research reactor ``YAYOI'' of the University of Tokyo and ``JRR-4'' of JAERI also demonstrate that excitational efficiency is maximized in a similar gas mixture predicted by the calculation.

  20. Performance of self-powered neutron detectors in pressurized water reactors

    International Nuclear Information System (INIS)

    Warren, H.D.; Bozarch, D.P.

    1977-01-01

    A typical Babcock and Wilcox pressurized water reactor (PWR) contains 364 rhodium self-powered neutron detectors (SPNDs) and 52 background detectors. The detectors are inserted into the reactor core in 52 dry, multidetector assemblies. Each assembly contains seven SPNDs and one background detector. By mid-1977, eight B and W PWRs, each fitted with SPNDs, were in operation. Many of the SPNDs have operated successfully for more than four years. This paper describes the operational performance of the SPNDs and special tests conducted to improve that performance. Topics included are (1) insulation performance versus neutron dose to the SPND, (2) background signals in the leadwire region of the SPND, and (3) depletion of the SPND emitter versus absorbed neutron dose

  1. Measuring delayed part of the current of a self powered neutron detector and comparison with calculations

    International Nuclear Information System (INIS)

    Kophazi, J.; Czifrus, Sz.; Feher, S.; Por, G.

    2001-01-01

    The paper describes the measurement of the delayed signal of a Rh emitter Self Powered Neutron Detector (SPND) separately from other signal components originating from (n-gamma-e), (background gamma-e) and other effects. In order to separate the delayed signal, the detector was removed from the reactor core and placed to an adequately distant location during the measurement, where the radiation from the core was negligible. The experiment was carried out on the 100kW light water tank-type reactor of Technical University of Budapest and the results of the measurement were compared with the results of Monte Carlo calculations.(author)

  2. Comparison of Thermal Neutron Flux Measured by Uranium 235 Fission Chamber and Rhodium Self-Powered Neutron Detector in MTR

    International Nuclear Information System (INIS)

    Fourmentel, D.; Filliatre, P.; Barbot, L.; Villard, J.-F.; Lyoussi, A.; Geslot, B.; Malo, J.-Y.; Carcreff, H.; Reynard-Carette, C.

    2013-06-01

    Thermal neutron flux is one of the most important nuclear parameter to be measured on-line in Material Testing Reactors (MTRs). In particular two types of sensors with different physical operating principles are commonly used: self-powered neutron detectors (SPND) and fission chambers with uranium 235 coating. This work aims to compare on one hand the thermal neutron flux evaluation given by these two types of sensors and on the other hand to compare these evaluations with activation dosimeter measurements, which are considered as the reference for absolute neutron flux assessment. This study was conducted in an irradiation experiment, called CARMEN-1, performed during 2012 in OSIRIS reactor (CEA Saclay - France). The CARMEN-1 experiment aims to improve the neutron and photon flux and nuclear heating measurements in MTRs. In this paper we focus on the thermal neutron flux measurements performed in CARMEN-1 experiment. The use of fission chambers to measure the absolute thermal neutron flux in MTRs is not very usual. An innovative calibration method for fission chambers operated in Campbell mode has been developed at the CEA Cadarache (France) and tested for the first time in the CARMEN-1 experiment. The results of these measurements are discussed, with the objective to measure with the best accuracy the thermal neutron flux in the future Jules Horowitz Reactor. (authors)

  3. Rhodium self-powered detector for monitoring neutron fluence, energy production, and isotopic composition of fuel

    International Nuclear Information System (INIS)

    Sokolov, A.P.; Pochivalin, G.P.; Shipovskikh, Yu.M.; Garusov, Yu.V.; Chernikov, O.G.; Shevchenko, V.G.

    1993-01-01

    The use of self-powered detectors (SPDs) with a rhodium emitter customarily involves monitoring of neutron fields in the core of a nuclear reactor. Since current in an SPD is generated primarily because of the neutron flux, which is responsible for the dynamics of particular nuclear transformations, including fission reactions of heavy isotopes, the detector signal can be attributed unambiguously to energy release at the location of the detector. Computation modeling performed with the KOMDPS package of programs of the current formation in a rhodium SPD along with the neutron-physical processes that occur in the reactor core makes it possible to take account of the effect of the principal factors characterizing the operating conditions and the design features of the fuel channel and the detector, reveal quantitative relations between the generated signal and individual physical parameters, and determine the metrological parameters of the detector. The formation and transport of changed particles in the sensitive part of the SPC is calculated by the Monte Carlo method. The emitter activation, neutron transport, and dynamics of the isotopic composition in the fuel channel containing the SPD are determined by solving the kinetic equation in the multigroup representation of the neutron spectrum, using the discrete ordinate method. In this work the authors consider the operation of a rhodium SPD in a bundle of 49 fuel channels of the RBMK-1000 reactor with a fuel enrichment of 2.4% from the time it is inserted into a fresh channel

  4. Neutron and gamma sensitivities of self-powered detectors: Monte Carlo modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vermeeren, Ludo [SCK-CEN, Nuclear Research Centre, Boeretang 200, B-2400 Mol, (Belgium)

    2015-07-01

    This paper deals with the development of a detailed Monte Carlo approach for the calculation of the absolute neutron sensitivity of SPNDs, which makes use of the MCNP code. We will explain the calculation approach, including the activation and beta emission steps, the gamma-electron interactions, the charge deposition in the various detector parts and the effect of the space charge field in the insulator. The model can also be applied for the calculation of the gamma sensitivity of self-powered detectors and for the radiation-induced currents in signal cables. The model yields detailed information on the various contributions to the sensor currents, with distinct response times. Results for the neutron sensitivity of various types of SPNDs are in excellent agreement with experimental data obtained at the BR2 research reactor. For typical neutron to gamma flux ratios, the calculated gamma induced SPND currents are significantly lower than the neutron induced currents. The gamma sensitivity depends very strongly upon the immediate detector surroundings and on the gamma spectrum. Our calculation method opens the way to a reliable on-line determination of the absolute in-pile thermal neutron flux. (authors)

  5. Responses of platinum, vanadium and cobalt self-powered flux detectors near simulated booster rods in a ZED-2 mockup of a Bruce reactor core

    International Nuclear Information System (INIS)

    French, P.M.; Shields, R.B.; Kroon, J.C.

    1978-02-01

    The static responses of Pt, V and Co self-powered detectors have been compared with copper-foil neutron activation profiles in reference and perturbed Bruce reactor core mockups assembled in the ZED-2 test reactor at Chalk River Nuclear Laboratories. The results indicate that the normalized response of each self-powered detector is an accurate measure of the thermal-neutron flux at locations greater than one lattice pitch from either a booster rod or the core boundary. They indicate that, in the Bruce booster/detector configuration, the normalized static Pt response overestimates the neutron flux by less than 3.5% upon full booster-rod insertion. (author)

  6. Self-powered detectors sensitivity determination

    International Nuclear Information System (INIS)

    Surkov, V.; Soares, A.J.

    1994-01-01

    The determination of the initial sensitivity of Self Powered Detectors (SPDs) was performed. Measurements of thermal, epithermal and to gamma flux sensitivities were made with Vanadium, Cobalt, Rhodium, Silver and Platinum SPDs and, when possible, the values are compared with the ones from the existing literature. The determination of neutron sensitivity was realized using the IEA-R1 Reactor from IPEN. The thermal and epithermal neutron flux were determined with bare and Cadmium covered activation foils. (GOLD). (author)

  7. Self-Powered Neutron Detector Qualification for Absolute On-Line In-Pile Neutron Flux Measurements in BR2

    Science.gov (United States)

    Vermeeren, L.; Wéber, M.

    2003-06-01

    A set of ten Self-Powered Neutron Detectors with Co, Rh and Ag emitters has been irradiated in several channels of the BR2 research reactor at SCK•CEN aiming at a comparison of their performance as thermal neutron flux detectors under various conditions. To allow for a correct interpretation of their signals, all detector sensitivity contributions (prompt and delayed) were calculated using a dedicated Monte Carlo model. The various contributions were also measured separately; the agreement between calculated and experimental data, including data from activation dosimetry, was excellent. Detailed neutron flux profiles were obtained from the SPND data, after correction for the finite detector lengths and for the slow response of delayed SPNDs.

  8. Self-Powered Neutron Detector Calibration Using a Large Vertical Irradiation Hole of HANARO

    Directory of Open Access Journals (Sweden)

    Kim Myong-Seop

    2018-01-01

    Full Text Available A calibration technology of the self-powered neutron detectors (SPNDs using a large vertical irradiation hole of HANARO is developed. The 40 Rh-SPNDs are installed on the polycarbonate plastic support, and the gold wires with the same length as the effective length of the rhodium emitter of the SPND are also installed to measure the neutron flux on the SPND. They are irradiated at a low reactor power, and the SPND current is measured using the pico-ammeter. The external gamma-rays which affect the SPND current response are analyzed using the Monte Carlo simulation for various irradiation conditions in HANARO. It is confirmed that the effect of the external gamma-rays to the SPND current is dependent on the reactor characteristics, and that it is affected by materials around the detector. The current signals due to the external gamma-rays can be either positive or negative, in that the net flow of the current may be either in the same or the opposite direction as the neutron-induced current by the rhodium emitter. From the above procedure, the effective calibration methodology of multiple SPNDs using the large hole of HANARO is developed. It could be useful for the calibration experiment of the neutron detectors in the research reactors.

  9. Self-Powered Neutron Detector Calibration Using a Large Vertical Irradiation Hole of HANARO

    Science.gov (United States)

    Kim, Myong-Seop; Park, Byung-Gun; Kang, Gi-Doo

    2018-01-01

    A calibration technology of the self-powered neutron detectors (SPNDs) using a large vertical irradiation hole of HANARO is developed. The 40 Rh-SPNDs are installed on the polycarbonate plastic support, and the gold wires with the same length as the effective length of the rhodium emitter of the SPND are also installed to measure the neutron flux on the SPND. They are irradiated at a low reactor power, and the SPND current is measured using the pico-ammeter. The external gamma-rays which affect the SPND current response are analyzed using the Monte Carlo simulation for various irradiation conditions in HANARO. It is confirmed that the effect of the external gamma-rays to the SPND current is dependent on the reactor characteristics, and that it is affected by materials around the detector. The current signals due to the external gamma-rays can be either positive or negative, in that the net flow of the current may be either in the same or the opposite direction as the neutron-induced current by the rhodium emitter. From the above procedure, the effective calibration methodology of multiple SPNDs using the large hole of HANARO is developed. It could be useful for the calibration experiment of the neutron detectors in the research reactors.

  10. The use of self-powered neutron detectors (SPN) to measure reactor power

    International Nuclear Information System (INIS)

    Hamidian, M.R.

    1974-01-01

    Due to the complicated design and technical difficulties of the conventional chamber method, neutron flux measurement between fuel rods is not possible. SPN detectors have a very simple design and a small size; therefore, they are suitable for the use inside the space available in the reactor core. The SPN detector consists of an emitter which emits particles by neutron absorption. The particles penetrate in an insulator and reach an outer collector. Among fission products, electrons might be produced by photoeffect or compton effect, internal conversion or pair production which, will also reach the collector. Cobalt and rhodium emitters have found practical application because of their fast response and sensitivity. The (n, γ) reaction in 103 Rh and 60 Co yields several isotopes and isomers which are discussed in the present report

  11. Analysis and solution of current spike occurred in dynamic compensation of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Peng, Xingjie; Li, Qing; Wang, Kan

    2017-01-01

    Highlights: • The current spike problem is observed in the dynamic compensation process of SPNDs. • The current spike is caused by unphysical current change due to range switching. • Modification on the compensation algorithm is introduced to deal with current spike. - Abstract: Dynamic compensation methods are required to improve the response speed of the Self-Powered Neutron Detectors (SPNDs) and make it possible to apply the SPNDs for core monitoring and surveillance. During the experimental test of the compensation method based on linear matrix inequality (LMI), spikes are observed in the compensated SPND current. After analyzing the measurement data, the cause is fixed on the unphysical change of the uncompensated SPND current due to range switching. Then some modifications on the dynamic compensation algorithms are proposed to solve the current spike problem.

  12. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Verma, V., E-mail: vasudha.verma@physics.uu.se [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Barbot, L.; Filliatre, P. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Hellesen, C. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Jammes, C. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Svärd, S. Jacobsson [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2017-07-11

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment. - Highlights: • Studied possibility of using SPNDs as in-core detectors in SFRs. • Study done to detect local power profile changes when reactor is at nominal power. • SPND with a Pt-emitter gives measurable prompt current of the order of 600 nA/m. • Dominant proportion of prompt response is maintained throughout the operation. • Detector signal gives dynamic information on the power fluctuations.

  13. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Science.gov (United States)

    Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson

    2017-07-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.

  14. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments.

    Science.gov (United States)

    Miller, Marcelo E; Sztejnberg, Manuel L; González, Sara J; Thorp, Silvia I; Longhino, Juan M; Estryk, Guillermo

    2011-12-01

    A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comisión Nacional de Energía Atómica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Local mixed-field thermal neutron sensitivities and global thermal and mixed

  15. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Marcelo E.; Sztejnberg, Manuel L.; Gonzalez, Sara J.; Thorp, Silvia I.; Longhino, Juan M.; Estryk, Guillermo [Comision Nacional de Energia Atomica, Av. del Libertador 8250, Ciudad de Buenos Aires 1429 (Argentina); Comision Nacional de Energia Atomica, Av. del Libertador 8250, Ciudad de Buenos Aires 1429, Argentina and CONICET, Av. Rivadavia 1917, Ciudad de Buenos Aires 1033 (Argentina); Comision Nacional de Energia Atomica, Av. del Libertador 8250, Ciudad de Buenos Aires 1429 (Argentina)

    2011-12-15

    Purpose: A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comision Nacional de Energia Atomica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. Methods: The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Results: Local mixed-field thermal neutron sensitivities and

  16. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments

    International Nuclear Information System (INIS)

    Miller, Marcelo E.; Sztejnberg, Manuel L.; Gonzalez, Sara J.; Thorp, Silvia I.; Longhino, Juan M.; Estryk, Guillermo

    2011-01-01

    Purpose: A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comision Nacional de Energia Atomica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. Methods: The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Results: Local mixed-field thermal neutron sensitivities and global

  17. A study on the sensitivity of self-powered neutron detectors (SPNDs) and a new proposal

    International Nuclear Information System (INIS)

    Lee, Wan No; Cho, Gyu Seong

    1997-01-01

    Self-Powered Neutron Detectors (SPNDs) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. In this paper, Monte Carlo simulation is accomplished to calculate the escape probability of beta particle as a function of their birth position for the typical geometry of rhodium-based SPNDs. Also, a simple numerical method calculates the initial generation rate of beta particles and the change of generation rate due to rhodium burn-up. Using the simulation and the numerical method, the burn-up profile of rhodium density and the neutron sensitivity are calculated as a function of burn-up time in the reactor. The sensitivity of the SPNDs decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. In addition, for improvement of some properties of rhodium-based SPNDs which are currently used, this paper presents a new material. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long term usage

  18. A study on the sensitivity of self-powered neutron detectors (SPNDs)

    Science.gov (United States)

    Lee, Wanno; Cho, Gyuseong; Kim, Kwanghyun; Kim, Hee Joon; choi, Yuseon; Park, Moon Chu; Kim, Soongpyung

    2001-08-01

    Self-powered neutron detectors (SPNDs) are widely used in reactors to monitor neutron flux, while they have several advantages such as small size, and relatively simple electronics required in conjunction with those usages, they have some intrinsic problems of the low level of output current-a slow response time and the rapid change of sensitivity-that make it difficult to use for a long term. Monte Carlo simulation was used to calculate the escape probability as a function of the birth position of emitted beta particle for geometry of rhodium-based SPNDs. A simple numerical method calculated the initial generation rate of beta particles and the change of generation rate due to rhodium burnup. Using results of the simulation and the simple numerical method, the burnup profile of rhodium number density and the neutron sensitivity were calculated as a function of burnup time in reactors. This method was verified by the comparison of this and other papers, and data of YGN3.4 (Young Gwang Nuclear plant 3, 4) about the initial sensitivity. In addition, for improvement of some properties of rhodium-based SPNDs, which are currently used, a modified geometry is proposed. The proposed geometry, which is tube-type, is able to increase the initial sensitivity due to increase of the escape probability. The escape probability was calculated by changing the thickness of the insulator and compared solid-type with tube-type about each insulator thickness. The method used here can be applied to the analysis and design of other types of SPNDs.

  19. Development of high sensitivity transimpedance amplifier module for self powered neutron detectors

    International Nuclear Information System (INIS)

    Khan, T.K.; Tamboli, P.K.; Antony, J.; Balasubramanian, R.; Agilandaeswari, K.; Pramanik, M.

    2010-01-01

    This paper describes design and development of a Transimpedance Amplifier for amplification of very low current from in core Self Powered Neutron Detectors (SPND). Measurement of neutron flux is very important for operation, control and protection of Nuclear Power Plant (NPP). SPND is used to measure Reactor incore flux/power. Based on sensitivity of emitter material used in SPND, pitch length and neutron flux (power level); the current output from SPND varies from few pA to few μA. The described amplifier is suitable to use for this current range. The amplifier provides a very high gain using a resistive T network feedback topology. The amplifier is designed in two stages using ultra low bias current FET OPAMPs. Design of Transimpedance amplifier is carefully done to include ultra low input bias current, low offset voltage and noise. The amplifier has in built test facility for calibration and on line test facility for measurement of insulation resistance (IR). The amplifier module has on board isolated DC-DC converter circuit complying MIL/STD/461C/D which generate isolated +/-15V and +12V supply to provide parameter to parameter ground isolation and independence among each module/signal.The output from the amplifier is 0V to 6V for 0 to 150%FP. The design is simulated in computer and amplifier used at TAPS-3 was modified as per new design and has been tested at TAPS-3 site. The amplifier performed satisfactorily. The results showed that the IR measurement technique adopted in the design can tolerate lower IR of SPND in existing design. (author)

  20. Self-powered detectors with thulium emitter

    International Nuclear Information System (INIS)

    Haller, P.; Klar, E.

    1978-01-01

    In addition to fission chambers, prompt-indicating self-powered (SPN) detectors are used for measuring the neutron flux density in the core of power reactors. Although current SPN detectors with a cobalt emitter give satisfactora results, detectors with other emitter materials have been analyzed and tested. The author describes the properties and decay pattern of the nuclide thulium and presents the results of measurements made while testing thulium detectors. (orig.) [de

  1. Long-term performance of the CANDU-type of vanadium self-powered neutron detectors in NRU

    Energy Technology Data Exchange (ETDEWEB)

    Leung, T.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]. E-mail: leungt@aecl.ca

    2007-07-01

    The CANDU-type of in-core vanadium self-powered neutron flux detectors have been installed in NRU to monitor the axial neutron flux distributions adjacent to the loop fuel test sites since 1996. This paper describes how the thermal neutron fluxes were measured at two monitoring sites, and presents a method of correcting the vanadium burn-up effect, which can be up to 2 to 3% per year, depending on the detector locations in the reactor. It also presents the results of measurements from neutron flux detectors that have operated for over eight-years in NRU. There is good agreement between the measured and simulated neutron fluxes, to within {+-} 6.5%, and the long-term performance of the CANDU-type of vanadium neutron flux detectors in NRU is satisfactory. (author)

  2. A study on the sensitivity of self-powered neutron detectors(SPNDs)

    International Nuclear Information System (INIS)

    Lee, Wan No

    1997-02-01

    Self-Powered Neutron Detectors(SPND) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. While they have several advantages such as small size, low cost, and relatively simple electronics required in conjunction with those usage, they have some intrinsic problems of the low level of output current, a slow response time, the rapid change of sensitivity which makes it difficult to use for a long term. In this paper, Monte Carlo simulation is accomplished to calculate the escape probability as a function of the birth position of emitted beta particle for a geometry of rhodium-based SPNDs. A simple numerical method calculates the initial generation rate of beta particles and the change of generation rate due to rhodium burn-up. Using the simulation result, the burn-up profile of rhodium number density and the neutron sensitivity are calculated as a function of burn-up time in reactors. The sensitivity of the SPND decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. In addition, for improvement of some properties of rhodium-based SPNDs which are currently used, this paper presents a new material and modified geometry. From searching nuclear data, Ag 109 is chosen as a replacing material for rhodium. Silver has a low neutron absorption cross-section and a high beta energy and a low density when it is compared with rhodium. The sensitivity and the density change of silver as a function of burn-up are calculated using this method. Also, this paper compares the initial sensitivity of a solid type with its of a tube type. The initial sensitivity is increased with the new material and the tube type. Silver is also found to be used for longer time than rhodium. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long term usage

  3. Large-area self-powered neutron-detectors for neutron-flux measurements in HTRs. Status of developmental work

    International Nuclear Information System (INIS)

    Brixy, H.; Hecker, R.; Serpekian, T.; Benninghofen, G.; Serafin, N.; Spillekothen, H.G.

    1982-06-01

    The development is described of the large-area SPN-detector as an out of core power monitoring system. Gadolinium or cobalt was used as the emitter. Response functions of the gadolinium SPN-detector were found with regard to the reactor power, the effect of the gamma field, its short-term behaviour following reactor shutdown and long-term behaviour during reactor operation. It was shown that a detector of 0.1 mm emitter thickness can withstand an integral thermal neutron flux of 2.10 20 nvt almost without efficiency loss thus indicating that the large-area gadolinium SPN-detector is a suitable means for power monitoring in large HTGR's

  4. Implantable self-powered detector for on-line determination of neutron flux in patients during NCT treatment.

    Science.gov (United States)

    Miller, M E; Mariani, L E; Gonçalves-Carralves, M L Sztejnberg; Skumanic, M; Thorp, S I

    2004-11-01

    A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.

  5. Implantable self-powered detector for on-line determination of neutron flux in patients during NCT treatment

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.E. E-mail: miller@cae.cnea.gov.ar; Mariani, L.E.; Sztejnberg Goncalves-Carralves, M.L.; Skumanic, M.; Thorp, S.I

    2004-11-01

    A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.

  6. Cobalt

    International Nuclear Information System (INIS)

    Stolyarova, I.A.; Bunakova, N.Yu.

    1983-01-01

    The neutron-activation method for determining cobalt in rocks, polymetallic and iron ores and rockforming minerals at 2x10 -6 -5x10 -3 % content is developed. Cobalt determination is based on the formation under the effect of thermal neutrons of nuclear reactor of the 60 Co radioactive isotope by the 59 Co (n, γ) 60 Co reaction with radiation energy of the most intensive line of 1333 keV. Cobalt can be determined by the scheme of the multicomponent analysis from the sample with other elements. Co is determined in the solution after separation of all determinable by the scheme elements. The 60 Co intensity is measured by the mUltichannel gamma-spectrometer with Ge(Li)-detector

  7. Activation of cobalt by neutrons from the Hiroshima bomb

    International Nuclear Information System (INIS)

    Kerr, G.D.; Dyer, F.F.; Emery, J.F.; Pace, J.V. III; Brodzinski, R.L.; Marcum, J.

    1990-02-01

    A study has been completed of cobalt activation in samples from two new locations in Hiroshima. The samples consisted of a piece of steel from a bridge located at a distance of about 1300 m from the hypocenter and pieces of both steel and concrete from a building located at approximately 700 m. The concrete was analyzed to obtain information needed to calculate the cobalt activation in the two steel samples. Close agreement was found between calculated and measured values for cobalt activation of the steel sample from the building at 700 m. It was found, however, that the measured values for the bridge sample at 1300 m were approximately twice the calculated values. Thus, the new results confirm the existence of a systematic error in the transport calculations for neutrons from the Hiroshima bomb. 52 refs., 32 figs., 16 tabs

  8. Absolute on-line in-pile measurement of neutron fluxes using self-powered neutron detectors: Monte Carlo sensitivity calculations

    Energy Technology Data Exchange (ETDEWEB)

    Vermeeren, L. [SCK/CEN, B-2400 Mol (Belgium)

    2001-07-01

    Self-powered neutron detectors (SPND) are well suited to monitor continuously the neutronic operating conditions of driver fuel of research reactors and to follow its burnup evolution. This is of particular importance when advanced or new MTR fuel designs need to be qualified. We have developed a detailed MCNP-4B based Monte Carlo approach for the calculation of neutron sensitivities of SPNDs. Results for the neutron sensitivity of a Rh SPND are in excellent agreement with experimental data recently obtained at the BR2 research reactor. A critical comparison of the Monte Carlo results with results from standard analytical methods reveals an important deficiency of the analytical methods in the description of the electron transport efficiency. Our calculation method allows a reliable on-line determination of the absolute in-pile neutron flux. (author)

  9. Absolute on-line in-pile measurement of neutron fluxes using self-powered neutron detectors: Monte Carlo sensitivity calculations

    International Nuclear Information System (INIS)

    Vermeeren, L.

    2001-01-01

    Self-powered neutron detectors (SPND) are well suited to monitor continuously the neutronic operating conditions of driver fuel of research reactors and to follow its burnup evolution. This is of particular importance when advanced or new MTR fuel designs need to be qualified. We have developed a detailed MCNP-4B based Monte Carlo approach for the calculation of neutron sensitivities of SPNDs. Results for the neutron sensitivity of a Rh SPND are in excellent agreement with experimental data recently obtained at the BR2 research reactor. A critical comparison of the Monte Carlo results with results from standard analytical methods reveals an important deficiency of the analytical methods in the description of the electron transport efficiency. Our calculation method allows a reliable on-line determination of the absolute in-pile neutron flux. (author)

  10. An evaluated neutronic data file for elemental cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, P.; Lawson, R.; Meadows, J.; Sugimoto, M.; Smith, A.; Smith, D.; Howerton, R.

    1988-08-01

    A comprehensive evaluated neutronic data file for elemental cobalt is described. The experimental data base, the calculational methods, the evaluation techniques and judgments, and the physical content are outlined. The file contains: neutron total and scattering cross sections and associated properties, (n,2n) and (n,3n) processes, neutron radiative capture processes, charged-particle-emission processes, and photon-production processes. The file extends from 10/sup /minus/5/ eV to 20 MeV, and is presented in the ENDF/B-VI format. Detailed attention is given to the uncertainties and correlations associated with the prominent neutron-induced processes. The numerical contents of the file have been transmitted to the National Nuclear Data Center, Brookhaven National Laboratory. 143 refs., 16 figs., 5 tabs.

  11. Rhodium self-powered neutron detector's lifetime for korean standard nuclear power plants

    International Nuclear Information System (INIS)

    Yoo, Choon Sung; Kim, Byoung Chul; Park, Jong Ho; Fero, Arnold H.; Anderson, S. L.

    2005-01-01

    A method to estimate the relative sensitivity of a self-powered rhodium detector for an upcoming cycle is developed by combining the rhodium depletion data from a nuclear design with the site measurement data. This method can be used both by nuclear power plant designers and by site staffs of Korean standard nuclear power plants for determining which rhodium detectors should be replaced during overhauls

  12. Environmental effects on the response of self-powered flux detectors in CANDU reactors

    International Nuclear Information System (INIS)

    Lynch, G.F.; Shields, R.B.; Joslin, C.W.

    1976-01-01

    Self-powered flux detectors are playing an increasingly important role in the control and safety systems of CANDU-type reactors. In this paper we report on recent experiments to determine how local reactor conditions affect the output signals from self-powered detectors with vanadium, platinum and cobalt emitters. The results are interpreted in terms of variations in the local neutron, γ-ray and electron fluxes. (author)

  13. Thermal neutron flux measurement using self-powered neutron detector (SPND) at out-core locations of TRIGA PUSPATI Reactor (RTP)

    Science.gov (United States)

    Ali, Nur Syazwani Mohd; Hamzah, Khaidzir; Mohamad Idris, Faridah; Hairie Rabir, Mohamad

    2018-01-01

    The thermal neutron flux measurement has been conducted at the out-core location using self-powered neutron detectors (SPNDs). This work represents the first attempt to study SPNDs as neutron flux sensor for developing the fault detection system (FDS) focusing on neutron flux parameters. The study was conducted to test the reliability of the SPND’s signal by measuring the neutron flux through the interaction between neutrons and emitter materials of the SPNDs. Three SPNDs were used to measure the flux at four different radial locations which located at the fission chamber cylinder, 10cm above graphite reflector, between graphite reflector and tank liner and fuel rack. The measurements were conducted at 750 kW reactor power. The outputs from SPNDs were collected through data acquisition system and were corrected to obtain the actual neutron flux due to delayed responses from SPNDs. The measurements showed that thermal neutron flux between fission chamber location near to the tank liner and fuel rack were between 5.18 × 1011 nv to 8.45 × 109 nv. The average thermal neutron flux showed a good agreement with those from previous studies that has been made using simulation at the same core configuration at the nearest irradiation facilities with detector locations.

  14. Self-powered radiation detector

    International Nuclear Information System (INIS)

    Playfoot, K.C.; Bauer, R.F.; Goldstein, N.P.

    1980-01-01

    This invention relates to a self powered radiation detector requiring no excitation potential to generate a signal indicating a radiation flux. Such detectors comprise two electrically insulated electrodes, at a distance from each other. These electrodes are made of conducting materials having a different response for neutron and/or gamma ray radiation flux levels, as in nuclear power stations. This elongated detector generates an electric signal in terms of an incident flux of radiations cooperating with coaxial conductors insulated from each other and with different radiation reaction characteristics. The conductor with the greatest reaction to the radiations forms the central emitting electrode and the conductor with the least reaction to the radiations forms a tubular coaxial collecting electrode. The rhodium or cobalt tubular emitting electrode contains a ductile central conducting cable placed along the longitudinal axis of the detector. The latter is in high nickel steel with a low reaction to radiation [fr

  15. Boiling detection using signals of self-powered neutron detectors and thermocouples

    International Nuclear Information System (INIS)

    Kozma, R.

    1989-01-01

    A specially-equipped simulated fuel assembly has been placed into the core of the 2 MW research reactor of the IRI, Delft. In this paper the recent results concerning the detection of coolant boiling in the simulated fuel assembly are introduced. Applying the theory of boiling temperature noise, different stages of boiling, i.e. one-phase flow, subcooled boiling, volume boiling, were identified in the measurements using the low-frequency noise components of the thermocouple signals. It has been ascertained that neutron noise spectra remained unchanged when subcooled boiling appeared, and that they changed reasonably only when developed volume boiling took place in the channels. At certain neutron detector positions neutron spectra did not vary at all, although developed volume boiling occurred at a distance of 3-4 cm from these neutron detectors. This phenomenon was applied in studying the field-of-view of neutron detectors

  16. Design and fabrication of self-powered in-core neutron flux monitor assembly

    International Nuclear Information System (INIS)

    Chung, M.K.; Cho, S.W.; Kang, H.D.; Cho, K.K.; Cho, B.S.; Kang, S.S.

    1980-01-01

    This is the final report on the prototypical fabrication of an in-core neutron flux monitor detector assembly for a specific power reactor conducted by KAERI from July 1, 1978 to December 31, 1979. It is well known that power reactors require a large number of in-core neutron flux detector for reactor regulation and the structures of detector assemblies are different from reactor to reactor. Therefore, from the nature of this project, it should be noted here that the target model of the prototypical farbrication of an in-core neutron flux monitor detector assembly is a VFD-2 System for Wolsung CANDU. It is concluded that fabrication of in-core neutron flux monitor detector assembly for CANDU reactor is technically feasible and will bring economical benefit as much as 50 % of the unit price if they are fabricated in Korea by using partially materials which are available from local market. (author)

  17. H{infinity} Filtering for Dynamic Compensation of Self-Powered Neutron Detectors - A Linear Matrix Inequality Based Method -

    Energy Technology Data Exchange (ETDEWEB)

    Park, M.G.; Kim, Y.H.; Cha, K.H.; Kim, M.K. [Korea Electric Power Research Institute, Taejon (Korea)

    1999-07-01

    A method is described to develop and H{infinity} filtering method for the dynamic compensation of self-powered neutron detectors normally used for fixed incore instruments. An H{infinity} norm of the filter transfer matrix is used as the optimization criteria in the worst-case estimation error sense. Filter modeling is performed for both continuous- and discrete-time models. The filter gains are optimized in the sense of noise attenuation level of H{infinity} setting. By introducing Bounded Real Lemma, the conventional algebraic Riccati inequalities are converted into Linear Matrix Inequalities (LMIs). Finally, the filter design problem is solved via the convex optimization framework using LMIs. The simulation results show that remarkable improvements are achieved in view of the filter response time and the filter design efficiency. (author). 15 refs., 4 figs., 3 tabs.

  18. Dynamic compensation of the Silver self-powered neutron detector in the ramp program at the OSIRIS reactor

    International Nuclear Information System (INIS)

    Moulin, D.J.

    1994-01-01

    The Silver self-powered neutron detector (SPND) is a common detector used in the ramp program at the OSIRIS reactor. The Silver SPND signal is a reference during steady states, but its response is too slow for monitoring transient tests. In order to compensate for the inherent time delay a mathematical processing method of the Silver SPND signal was developed. Based on a convolution-type resolution of the kinetics equations, a dynamic compensation algorithm can be used for transient conditions as well as steady state conditions. A computer program reconstructs, in real-time, the dynamic neutron flux sensed by the Silver detector from the current measured between the emitter and the collector of the SPND. Although this method decreases slightly the signal-to-noise ratio, it maintains the SPND's characteristics and reduces the response time from about 10 minutes to less than 4 seconds for a step change in flux. This provides for prompt and accurate measurement of fuel rod power during ramp experiments in the OSIRIS reactor. This development makes the Silver SPND very suitable for many on-line monitoring applications

  19. Cadmium-emitter self-powered thermal neutron detector performance characterization & reactor power tracking capability experiments performed in ZED-2

    Energy Technology Data Exchange (ETDEWEB)

    LaFontaine, M.W., E-mail: physics@execulink.com [LaFontaine Consulting, Kitchener, Ontario (Canada); Zeller, M.B. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Nielsen, K. [Royal Military College of Canada, SLOWPOKE-2 Reactor, Kingston, Ontario (Canada)

    2014-07-01

    Cadmium-emitter self-powered thermal neutron flux detectors (SPDs), are typically used for flux monitoring and control applications in low temperature, test reactors such as the SLOWPOKE-2. A collaborative program between Atomic Energy of Canada, academia (Royal Military College of Canada (RMCC)) and industry (LaFontaine Consulting) was initiated to characterize the incore performance of a typical Cd-emitter SPD; and to obtain a definitive measure of the capability of the detector to track changes in reactor power in real time. Prior to starting the experiment proper, Chalk River Laboratories' ZED-2 was operated at low power (5 watts nominal) to verify the predicted moderator critical height. Test measurements were then performed with the vertical center of the SPD emitter positioned at the vertical mid-plane of the ZED-2 reactor core. Measurements were taken with the SPD located at lattice position L0 (near center), and repeated at lattice position P0 (in D{sub 2}O reflector). An ionization chamber (part of the ZED-2 control instrumentation) monitored reactor power at a position located on the south side of the outside wall of the reactor's calandria. These experiments facilitated measurement of the absolute thermal neutron sensitivity of the subject Cd-emitter SPD, and validated the power tracking capability of said SPD. Procedural details of the experiments, data, calculations and associated graphs, are presented and discussed. (author)

  20. Study on the sensitivity of Self-Powered Neutron Detectors (SPND) and its change due to burn-up

    International Nuclear Information System (INIS)

    Cho, Gyuseong; Lee, Wanno; Yoon, Jeong-Hyoun.

    1996-01-01

    Self-Powered Neutron Detectors (SPND) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. While they have several advantages such as small size, low cost, and relatively simple electronics required in conjunction with its usage, it has some intrinsic problems of the low level of output current, a slow response time, the rapid change of sensitivity which makes it difficult to use for a long term. In this paper, Monte Carlo simulation was accomplished to calculate the escape probability as a function of the birth position for the typical geometry of rhodium-based SPNDs. Using the simulation result, the burn-up profile of rhodium number density and the neutron sensitivity is calculated as a function of burn-up time in the reactor. The sensitivity of the SPND decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long-term usage. (author)

  1. Design and fabrication of a novel self-powered solid-state neutron detector

    Science.gov (United States)

    LiCausi, Nicholas

    There is a strong interest in intercepting special nuclear materials (SNM) at national and international borders and ports for homeland security applications. Detection of SNM such as U and Pu is often accomplished by sensing their natural or induced neutron emission. Such detector systems typically use thermal neutron detectors inside a plastic moderator. In order to achieve high detection efficiency gas filled detectors are often used; these detectors require high voltage bias for operation, which complicates the system when tens or hundreds of detectors are deployed. A better type of detector would be an inexpensive solid-state detector that can be mass-produced like any other computer chip. Research surrounding solid-state detectors has been underway since the late 1990's. A simple solid-state detector employs a planar solar-cell type p-n junction and a thin conversion material that converts incident thermal neutrons into detectable alpha-particles and 7Li ions. Existing work has typically used 6LiF or 10B as this conversion layer. Although a simple planar detector can act as a highly portable, low cost detector, it is limited to relatively low detection efficiency (˜10%). To increase the efficiency, 3D perforated p-i-n silicon devices were proposed. To get high efficiency, these detectors need to be biased, resulting in increased leakage current and hence detector noise. In this research, a new type of detector structure was proposed, designed and fabricated. Among several detector structures evaluated, a honeycomb-like silicon p-n structure was selected, which is filled with natural boron as the neutron converter. A silicon p+-n diode formed on the thin silicon wall of the honeycomb structure detects the energetic alpha-particles emitted from the boron conversion layer. The silicon detection layer is fabricated to be fully depleted with an integral step during the boron filling process. This novel feature results in a simplified fabrication process. Three

  2. Device for neutron flux monitoring in IEA-R1 reactor using rhodium self powered neutron detector; Dispositivo de mapeamento de fluxo de neutron atraves do SPN/Rodio no IEA-R1

    Energy Technology Data Exchange (ETDEWEB)

    Ricci Filho, Walter; Fernando, Alberto de Jesus; Jerez, Rogerio; Tondin, Julio B.M.; Pasqualetto, Hertz [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2000-07-01

    The IEA-R1 reactor has undergone a modernization tio increase its operating power to 5 MW, in order to allow a more efficient production of radioisotopes. The objective of this work is to provide the reactor with flux monitoring device using a rhodium self powered neutron detector. Self powered detectors are rugged miniature devices with are increasingly being used for fixed in core reactor monitoring both for safety purposes and flux mapping. The work presents the results obtained with Rhodium-SPND in several irradiation position inside the reactor core. (author)

  3. Neutron diffraction studies on cobalt substituted BiFeO3

    Science.gov (United States)

    Ray, J.; Biswal, A. K.; Acharya, S.; Babu, P. D.; Siruguri, V.; Vishwakarma, P. N.

    2013-02-01

    A dilute concentration of single phase Cobalt substituted Bismuth ferrite, BiFe1-XCoXO3; (x=0, 0.02) is prepared by sol-gel auto combustion method. Room temperature neutron diffraction patterns show no change in the crystal and magnetic structure upon cobalt doping. The calculation of magnetic moments shows 3.848 μB for Fe+ and 2.85 μB for Co3+. The cobalt is found to be in intermediate spin state.

  4. Speciation analysis of cobalt in foods by high-performance liquid chromatography and neutron activation analysis

    International Nuclear Information System (INIS)

    Muto, Toshio; Koyama, Motoko

    1994-01-01

    A combined method by coupling high-performance liquid chromatography (HPLC, as a separation method) with neutron activation analysis (as a detection method) have been applied to the speciation analysis of cobalt in daily foods (e.g. egg, fish and milk). Cobalt species including free cobalt, vitamin B 12 and protein-bound cobalt were separated with a preparative HPLC and a centrifuge. Subsequently, the determination of cobalt in the separated species was made by neutron activation analysis. The results showed that the content of the total cobalt in the foods was found to lie in the range 0.4-11ng/g(0.4-11ppb) based on wet weight. The compositions of free cobalt, vitamin B 12 and protein-bound cobalt were ranged 16-43%, 55-73%, 2.3-17%, respectively. These experimental evidences suggest that the combination of HPLC and neutron activation analysis is expected to be a useful tool for speciation analysis of trace elements in biological as well as environmental materials. (author)

  5. Numerische und experimentelle Untersuchungen zur Beschreibung der Wirkungsweise und Effektivität von grossflächigen hochsensitiven SPNDs : Self-Powered-Neutron-Detectors

    OpenAIRE

    Al-Dabagh, D.

    1981-01-01

    In the present work the neutron sensitivity of large surface "Self-Powered- Neutron-Detectors«SPNDs) is determined numericaily and experimentally. First a computer model for the parametric caIculation of the (n,$\\gamma$)-reaction rates in the emitter of the SPND was developed under use of the Monte-Carlo-Program KENO 11 ‘To determine the escape-probability of the electrons produced via Comptonor photoelectric effect by the emitter as weil as fron the surrounding isolator, a new Monte-Carlo-Pr...

  6. Development of signal processing electronics for self powered neutron detector signal with built-in on-line insulation monitoring [Paper No.:E3

    International Nuclear Information System (INIS)

    Das, Amitabha; Chaganty, S.P.

    1993-01-01

    Self powered neutron detectors (SPNDs) are employed to monitor in-core neutron flux in nuclear reactors for control, safety and mapping of in-core neutron flux. The d.c. current produced by SPND is converted into a proportional d.c. voltage, which in turn is used for various purposes stated above. This paper describes various features of the SPND amplifier developed in the Electronics Division of Bhabha Atomic Research Centre (BARC). It also outlines the principle of working of on-line monitoring of insulation resistance (IR) of the detector and associated mineral insulated (MI) and soft cables. The amplifier generates an alarm in case of the IR of the detector and the cable assembly falls below an accepted value or the cable is not connected to the amplifier and relieves the operator from periodic and manual checking of each of the individual detectors and ensures the validity of the signal for further processing. (author). 3 figs

  7. Cobalt

    Science.gov (United States)

    Slack, John F.; Kimball, Bryn E.; Shedd, Kim B.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Cobalt is a silvery gray metal that has diverse uses based on certain key properties, including ferromagnetism, hardness and wear-resistance when alloyed with other metals, low thermal and electrical conductivity, high melting point, multiple valences, and production of intense blue colors when combined with silica. Cobalt is used mostly in cathodes in rechargeable batteries and in superalloys for turbine engines in jet aircraft. Annual global cobalt consumption was approximately 75,000 metric tons in 2011; China, Japan, and the United States (in order of consumption amount) were the top three cobalt-consuming countries. In 2011, approximately 109,000 metric tons of recoverable cobalt was produced in ores, concentrates, and intermediate products from cobalt, copper, nickel, platinum-group-element (PGE), and zinc operations. The Democratic Republic of the Congo (Congo [Kinshasa]) was the principal source of mined cobalt globally (55 percent). The United States produced a negligible amount of byproduct cobalt as an intermediate product from a PGE mining and refining operation in southeastern Montana; no U.S. production was from mines in which cobalt was the principal commodity. China was the leading refiner of cobalt, and much of its production came from cobalt ores, concentrates, and partially refined materials imported from Congo (Kinshasa).The mineralogy of cobalt deposits is diverse and includes both primary (hypogene) and secondary (supergene) phases. Principal terrestrial (land-based) deposit types, which represent most of world’s cobalt mine production, include primary magmatic Ni-Cu(-Co-PGE) sulfides, primary and secondary stratiform sediment-hosted Cu-Co sulfides and oxides, and secondary Ni-Co laterites. Seven additional terrestrial deposit types are described in this chapter. The total terrestrial cobalt resource (reserves plus other resources) plus past production, where available, is calculated to be 25.5 million metric tons. Additional resources of

  8. The influence of rhodium burn-up on the sensitivity of rhodium self-powered neutron detectors

    International Nuclear Information System (INIS)

    Erben, O.

    1980-01-01

    Depression and self-shielding coefficients are presented for thermal and epithermal neutron flux densities. Functions are shown describing the distribution of beta particle sources on the emitter cross section for 0 to 50% rhodium burnup. The values are calculated of detector sensitivity to thermal and epithermal neutron flux densities for the said burnup for main types of rhodium SPN detectors made by SODERN. (J.B.)

  9. Improvement of core monitoring code cecor by the virtual segmentation of the self powered neutron detector loaded at Korean Standard Nuclear Plant

    International Nuclear Information System (INIS)

    Choi, T.; Jung, Y.S.

    2006-01-01

    Full text: Full text: Korean Standard Nuclear Plant uses Self Powered Neutron Detectors (SPNDs) to measure the neutron flux in the reactor core. The SPND's height is 40 cm and is located axially at the five different positions and 45 radial places. The design code simulated a reactor core is calculated by segmentation of the core. The segmentation is called as 'node', of which size is normally 20 cm. The axial height of the detector is larger than that of the node, and the larger detector's height maybe product some error on the axially complex shape. The analysis with the detector's signals showed some errors at the non-cosine axial flux shape. In order to reduce the errors for the shape, we tried to divide the detector by introducing the virtual boundary in the detector. Then, each axially 5 detectors had two virtual segmentations respectively and the detector's signal was divided by the inputs. So the more virtual detector's signals were gotten, the more accurate axial shape was produced. The result with virtual segmentations in a detector gave less deviation than the case without virtual segmentation (the current model). After the middle of cycle at the initial core specially, the axial neutron flux shape is changed to the saddle type one. The current model gave some error in Root Mean Square (RMS) between the measured value and the calculated one. The virtual segmentation model gave the better agreement at that time

  10. Self-powered flux detectors

    International Nuclear Information System (INIS)

    Shields, R.B.

    1983-02-01

    This bibliography attempts to cover the published literature on the class of radiation detectors most often referred to as 'self-powered'. For this purpose, self-powered detectors are defined as those that have two or more conducting electrodes separated by solid insulation and that generate a signal current without an external power source. Primary sensitivity is unrestricted, but it is usually to neutrons or gamma-rays. The main application is in the core of a nuclear reactor. All relevant facets of the subject are covered including: theory, experiment, development, design, manufacture, instrumentation and application. In addition to the usual reference information, various other designations are included where available, such as CONF-and abstract serial numbers. Where possible, a summary of the content is given with emphasis on specific results and conclusions. Indexing is by author and subject

  11. Determination of Cobalt in Seawater Using Neutron Activation Analysis after Preconcentration by Adsorption onto γ-MnO2 Nanomaterial

    Directory of Open Access Journals (Sweden)

    Van-Phuc Dinh

    2018-01-01

    Full Text Available The γ-MnO2 nanomaterial has been used to adsorb cobalt in the seawater at Phan Thiet City, Binh Thuan Province, Vietnam. Its concentration is determined by using the neutron activation analysis (NAA method at the Dalat nuclear research reactor. Factors affecting the uptake of cobalt on the γ-MnO2 material such as the pH, adsorption time, and initial cobalt(II concentration are investigated. The irradiated experiment data are calculated using the K0-Dalat program. The results obtained show that the trace dissolved cobalt in Phan Thiet seawater is found equal to 0.25 ± 0.04 μg/L (n=5, P=95% with the adsorption efficiency being higher than 95% (n=4, P=95%.

  12. Determination of selenium in samples of concentrated of nickel plus cobalt using the analysis through activation with epi thermic neutron

    International Nuclear Information System (INIS)

    Capote Rodriguez, G.; Perez Zayas, G.; Hernandez Rivero, A.; Moreno Bermudez, G.; Ribeiro Guevara, S.; Arribere, M.A.; Molina Insfran, J.

    1997-01-01

    In this work, the concentration of selenium and other elements was determined. Seventeen samples of sulfides plus cobalt were used. Among the employed methods for such purpose, the analysis was made through neutronic activation, in its instrumental variants, and by means of the application of radiochemical separation. (author) [es

  13. Response characteristics of self-powered flux detectors in CANDU reactors

    International Nuclear Information System (INIS)

    Allan, C.J.

    1978-05-01

    As part of the development of a new flux-detector assembly for future CANDU reactors, the sensitivities of a variety of vanadium, cobalt and platinum self-powered detectors have been determined in a simulated CANDU core installed in the ZED-2 test reactor at CRNL. While the vanadium and cobalt detectors had solid emitters, the platinum detectors were of two types, having either solid platinum emitters, or emitters consisting of a platinum sheath over an Inconel core. Almost all of the signal from the cobalt and vanadium detectors is due to neutron events in the emitters. For these detectors we have measured the total sensitivities per unit length. For the platinum detectors, reactor γ-rays and neutrons both contribute appreciably to the output signal, and in addition to the total sensitivity, we have determined the individual neutron and γ-ray sensitivities for these detectors. It was found that the detector sensitivities depend primarily on emitter diameter and that the observed variations can be fitted by means of power laws. (author)

  14. Uncertainties in measuring trace amounts of cobalt and europium with low-flux neutron activation analysis

    Directory of Open Access Journals (Sweden)

    Burnham Steven

    2017-01-01

    Full Text Available Neutron activation analysis is widely used for identification of elements and their quantities even in trace amounts in the samples of almost any type. The challenges in detecting trace amounts of particular elements are often associated with the neutron flux produced at the research reactors. Low-flux neutron activation analysis usually presents the biggest challenge when analyzing trace quantities of elements with lower magnitude of radiative capture cross-sections. In this paper, we present the methodology and the quantified uncertainties associated with the detection of trace amounts of cobalt and europium, using as an example concrete aggregates. Recent growing interest is in improving structural concrete (increasing its strength but reducing its activation in nuclear power plant environments. Aside from buildings, structural concrete is also used as a biological shield in nuclear power plant that become radioactive after exposure to neutron flux. Due to radiative capture interactions, artificial radionuclides are generated to high enough concentrations that classify concrete as low-level radioactive waste at the time of the plant's decommissioning. Disposal of this concrete adds to the expense of nuclear power plant financing and its construction. Three radionuclides, 60Co, 152Eu, and 154Eu, account for 99 % of total residual radioactivity of nuclear power plant decommissioned concrete. IAEA document RS-G-1.7, Application of the Concepts of Exclusion, Exemption, and Clearance, specifies clearance levels of radionuclides specific activities: a specific activity lower than 0.1 Bqg-1 for 60Co and 152Eu, and 154Eu allows for a concrete to be recycled after decommissioning of the nuclear power plant. Therefore, low-flux neutron activation analysis is used to test the detection limits of trace elements in samples of cement, coarse, and fine concrete aggregates. These samples are irradiated at the University of Utah's 100 kW TRIGA Reactor at

  15. Cobalt, fast neutrons and physical models: Nuclear data and measurements series

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.; Lawson, R.D.

    1987-07-01

    Energy-averaged neutron total cross sections of cobalt were measured from ≅0.5 to 12.0 MeV. Differential elastic- and inelastic-scattering cross sections were measured from ≅1.5 to 10.0 MeV over the scattering-angle range ≅18 0 to 160 0 , with sufficient detail to define the energy-averaged behavior. Inelastic neutron groups were observed corresponding to ''levels'' at: 1115 +- 29, 1212 +- 24, 1307 +- 24, 1503 +- 33, 1778 +- 40, 2112 +- 40, 2224 +- 35, 2423 +- 39, 2593 +- 41 and 2810 keV. The experimental results were interpreted in terms of the spherical optical-statistical and coupled-channels models. An unusually successful description of observables was achieved over a wide energy range ( 20.0 MeV) with a spherical model having energy-dependent strengths and geometries. The energy dependencies are large below ≅7.0 MeV (i.e., ≅19.0 MeV above the Fermi energy), but become smaller and similar to those reported for ''global'' potentials at higher energies. The imaginary strength is large and decreases with energy. These imaginary-potential characteristics are attributed to neutron shell closure and collective-vibrational processes. The weak-coupling model also offers an explanation of the unusual negative energy slope and relatively small radius of the imaginary potential. The spherical optical model derived from the neutron-scattering results was extrapolated to bound energies using the dispersion relationship and the method of moments. The resulting real-potential strength and radius peak at ≅-10.0 MeV, while concurrently the real diffuseness is at a minimum. The extrapolated potential is ≅8% larger than that implied by reported particle-state energies, and ≅13% smaller than indicated by hole-state energies. 68 refs., 15 figs., 1 tab

  16. Separation and purification of carrier-free cobalt-58 from neutron irradiated nickel foil for electrochemical studies

    International Nuclear Information System (INIS)

    Egamediev, S.; Nurbaeva, D.; Rakhmanov, A.

    2004-01-01

    Full text: Cobalt-58 will be used for tracer studies of the behaviour of cobalt radionuclides in no- carrier-added form during electrochemical deposition on metal backing. The 58 Co can be produced by using 58 Ni(n,p) 58 Co nuclear reaction in nuclear reactor. 58 Co (T 1/2 =71 days) decays by positron emitting (15%) and electron capture (85%) with simultaneous γ -irradiation. In this study, we have developed the simple method for separation and purification of 58 Co in no- carrier-added form from neutron irradiated nickel foil. Previously, we have studied the dissolution of nickel foil in various media to find best conditions for rapid dissolution of nickel target. It was found that nickel foil dissolved completely without heating in 6.3 M hydrobromic acid with addition a few drops of hydrogen peroxide. After dissolution of the target material, the cobalt-58 is separated from nickel, copper, iron and other elements by extraction chromatography. The solution in 6.3 M hydrobromic acid is passed through a column containing suspension of polytetrafluoroethylene powder with 0.5 M trioctylamine in xylene, equilibrated with the same acid. Nickel is not extracted and passed through column. Cobalt is retained and finally eluted with 3 M HBr in the one free column volume. The cobalt fraction is percolated through a column filled with suspension of pure polytetrafluoroethylene powder to purify from the admixture of extractant. The obtained solution is evaporated to dryness and the dry residue is treated by evaporation with aqua regia. After treatment the damp residue is dissolved in electrolyte and the obtained solution is used to study of 58 Co electrochemical deposition procedure. The yield of cobalt-58 was higher than 93% and the radiochemical purity was more than 99%. This method will be used for separation and purification of cobalt-57 to make of sealed sources for X-ray fluorescence analysis

  17. Review of some problems encountered with In-Core Fission chambers and Self-Powered Neutron Detectors in PWR's. Tests - Present use - Outlook on the near future

    International Nuclear Information System (INIS)

    Duchene, Jean; Verdant, Robert.

    1979-01-01

    The working conditions of in-core detectors are investigated as well as some reliability problems which depend on nuclear environment (such as decrease of sensibility, loss of insulation...). Then we review the long-term irradiation tests in experimental reactor that have been carried out by the CEA these last years, with fission chambers (FC) and Self-Powered Detectors (SPD). The travelling probe system with moveable FC used in the 900 MWe PWR is briefly described. Finally an outlook on future possibilities is given; for instance the use of fixed SPD and a moveable FC in the same thimble, allowing recalibration of the fixed detectors [fr

  18. A new self-powered flux detector

    International Nuclear Information System (INIS)

    Allan, C.J.

    1979-11-01

    It has been found that an Inconel-Inconel coaxial cable can be used as a fast-responding, neutron, self-powered flux detector if the core wire is sufficiently large. Test results obtained with such a detector, having a core wire approximately 1.5 mm in diameter, are presented. Other materials suitable for use as an emitter material, in such a relatively large diameter detector, also are included. (auth)

  19. Results and interpretation of noise measurements using in-core self powered neutron detector strings at Unit 2 of the Paks Nuclear Power Plant

    International Nuclear Information System (INIS)

    Gloeckler, O.; Por, G.; Valko, J.

    1986-11-01

    In-core neutron noise and fuel assembly outlet temperature noise measurements were performed at Unit 2 of Paks Nuclear Power Plant. Characteristics of the reactor and the noise measuring equipment are briefly described. The in-core Rhodium emitter selfpowered neutron detector strings positioned axially above the other show high coherence and linear phase at low frequencies indicating a marked transport effect, not regularly measured in PWRs. The coherence between horizontally placed neutron detectors is small and the phase is zero. A transport effect of different nature is obtained between neutron detectors (in-core and ex-core) and fuel assembly outlet thermocouples. The observed characteristics depend on reactor and fuel assembly power in a way supporting interpretation in terms of coolant density and void content changes and power feedback effects. During routine analysis vibration of 1.1 Hz appeared as a strong peak in the power spectra. The control assembly that was responsible for the observed behaviour could be localized with high certainty. (author)

  20. Numerical and experimental investigations to describe the mode of operation and effectivity of large surface high sensitive SPNDs (Self-Powered-Neutron-Detectors)

    International Nuclear Information System (INIS)

    Al-Dabagh, D.

    1981-08-01

    First a computer model for the parametric calculation of the (n,γ)-reaction rates in the emitter of the SPND was developed under use of the Monte-Carlo Program KENO II. To determine the escape-probability of the electrons produced via Compton- or photoelectric effect by the emitter as well as from the surrounding isolator, a new Monte-Carlo-Program was implemented under consideration of the Klein-Nishina-formula and the energy-range relationships for electrons. The approximate calculations performed for the electrons produced in the isolator show that the 'isolator flux' can give an important contribution to the total signal of the SPND. Subsequently with this program system an optimization of the neutron sensitivity was performed by a suitable choice of geometry (emitter thickness, isolator thickness). For a specially built large surface SPND with Gadolinium-emitter the neutron sensitivity was calculated. These results were checked by an In-Pile-Experiment in the FRJ-1 reactor. Very good agreement was found. The detector was also shown to exhibit excellent linearity and showed also the expected enhanced sensitivity. (orig./HP) [de

  1. Self-powered radiation detector

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1979-01-01

    Self-powered gamma radiation detector composed of a conducting emitter surrounded by an insulating medium and a conducting tubular collector, the emitter being a hollow tube containing an electrical insulator [fr

  2. Self-powered radiation detectors

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1982-01-01

    A self-powered nuclear radiation detector has an emitter electrode of an alloy of a first major constituent metal having a desired high radiation response, and a second minor constituent which imparts to the alloy a desired thermal or mechanical characteristic without diminishing the desired high radiation response. A gamma responsive self-powered detector is detailed which has an emitter with lead as the major constituent, with the minor constituent selected from aluminum, copper, nickel, platinum, or zinc. (author)

  3. Self-powered detectors for power reactors: an overview

    International Nuclear Information System (INIS)

    Ma, J.

    2006-01-01

    In this paper, Self-Powered Detectors (SPDs) for applications in nuclear power reactors have been reviewed. Based on their responses to radiation, these detectors can be divided into delayed response Self-Powered Neutron Detector (SPND), prompt response SPND and Self-Powered Gamma Detector (SPGD). The operational principles of these detectors are presented and their distinctive characteristics are examined accordingly. The analytical models and Monte Carlo method to calculate the responses of these detectors to neutron flux and external gamma rays are reviewed. The paper has also considered some related signal processing techniques, such as detector calibrations and detector signal compensations. Furthermore, a couple of failure modes have also been analyzed. Finally, applications of SPD in nuclear power reactors are summarized. (author)

  4. Self-powered detectors for power reactors: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Ma, J. [Univ. of Western Ontario, Dept. of Mechanical and Materials Engineering, London, Ontario (Canada)]. E-mail: jma64@uwo.ca

    2006-07-01

    In this paper, Self-Powered Detectors (SPDs) for applications in nuclear power reactors have been reviewed. Based on their responses to radiation, these detectors can be divided into delayed response Self-Powered Neutron Detector (SPND), prompt response SPND and Self-Powered Gamma Detector (SPGD). The operational principles of these detectors are presented and their distinctive characteristics are examined accordingly. The analytical models and Monte Carlo method to calculate the responses of these detectors to neutron flux and external gamma rays are reviewed. The paper has also considered some related signal processing techniques, such as detector calibrations and detector signal compensations. Furthermore, a couple of failure modes have also been analyzed. Finally, applications of SPD in nuclear power reactors are summarized. (author)

  5. Activation measurements for thermal neutrons. Part A. Cobalt (60Co) activation

    International Nuclear Information System (INIS)

    Kerr, George D.; Shizuma, Kiyoshi; Endo, Satoru; Maruyama, Takashi; Cullings, Harry M.; Komura, Kazuhisa; Okumura, Yutaka; Egbert, Stephen D.

    2005-01-01

    The 60 Co measurements at Hiroshima and Nagasaki were reviewed and compared with the results of the new DS02 calculations for the two cities. Some corrections were made to previously published data from the 1965 measurements of JNIRS, ground ranges of all of the 60 Co measurements were reviewed and new ground ranges were determined when possible by transforming sample coordinates to the new city maps for Hiroshima and Nagasaki, and transmission factors were investigated for a number of samples used in the 60 Co measurements. Transmission factors were not calculated for all samples used in the 60 Co measurements but some general rules were given for estimating transmission factors for these samples. Experimental measurements of the background 60 Co activity from environmental neutrons were also reviewed, and it was found that the 60 Co background from environmental neutrons was not an important factor in the 60 Co measurements of bomb-induced activity at either city. (J.P.N.)

  6. Concentration differences between serum and plasma of the elements cobalt, iron, mercury, rubidium, selenium and zinc determined by neutron activation analysis

    International Nuclear Information System (INIS)

    Kasperek, K.; Kiem, J.; Iyengar, G.V.; Feinendegen, L.E.

    1981-01-01

    The differences in concentrations of cesium, cobalt, iron, mercury, rubidium, selenium and zinc between serum and plasma were examined with the aid of instrumental neutron activation analysis. Eighty serum and plasma samples obtained from 13 donors were compared. Serum was prepared in plastic tubes immediately after clotting, and plasma was separated with heparin as anticoagulant. No significant differences in the concentrations of cesium, cobalt, mercury and selenium were observed. However, the concentrations of iron, rubidium and zinc were significantly higher in serum than in plasma. The average differences were 322, 12 and 20 ng/ml for iron, rubidium and zinc, respectively. The average differences found for cesium, rubidium and zinc were far below that which can be expected from a complete, or considerable release of these elements from platelets which aggregate or disintegrate during the clotting process in preparing serum. (orig.)

  7. Determination of iron, cobalt and zinc in caries teeth by neutron activation analysis

    International Nuclear Information System (INIS)

    Moriwaki, Kazunari; Shimpuku, Yasuhiro; Furuyama, Shunsuke

    1999-01-01

    The concentration of Fe, Zn and Co in caries teeth was determined by neutron activation analysis to compare with those of complete impacted wisdom teeth. In order to investigate the distribution of three elements, molar teeth were separated not by conventional method like precipitation or UV absorption method but by ashing method. Furthermore, the same elements for dental pulp and softened dentin were determined. The following results were obtained: The concentration of three elements (Fe, Zn and Co) in enamel, dentin and cementum of caries teeth was higher than that in control teeth. Enamel contained more Fe and Co than those in dentin or cementum, whereas Zn was found to be evenly distributed in three parts of the teeth. The concentration of the elements was Zn>Fe>Co in softened dentin, Fe>Zn>Co in dental pulp. (author)

  8. Scanning electron microscopy of mouse intestinal mucosa after cobalt 60 and D-T neutron irradiation

    International Nuclear Information System (INIS)

    Hamlet, R.; Carr, K.R.; Toner, P.G.; Nias, A.H.W.

    1976-01-01

    The stem-cell population of the intestinal crypt is an important model system in experimental radiobiology. Standardized techniques have been developed to allow quantitation of the response of crypt cells to radiation injury following doses of 0 to 2 krad of D-T neutrons or 60 Co γ rays. These techniques rely on the identification of regenerating crypt cells three-and-a-half days after irradiation. The results were expressed as the number of regenerating crypts per circumference of small intestine, as determined by conventional histological examination; the more profound the injury, the smaller the the crypt count. The practical relevance of crypt-counting techniques to clinical radiotherapy is limited by their relative insensitivity; the dose levels commonly used in fractionated radiotherapy produced no detectable response. Scanning electron microscopy of the mucosal surface provided a more sensitive measure of radiation injury. The earliest detectable changes occurred at the level of 300 rad of γ radiation, well below the threshold of the crypt-counting technique. At around 1,000 rad, where the first drop in crypt counts occurred, there were well-marked morphological changes which became more severe with increasing dose levels. Some differences have been observed between the morphological effects of γ and neutron irradiation at points of radiobiological equivalence in terms of crypt counts (using RBE value of about 2). The changes observed may reflect more than the disruption of epithelial cell kinetics. Mucosal morphology is the total expression of many different biological parameters of which the regenerative ability of the crypt cells is only one. The surface microanatomy of the gut may be the most sensitive indicator of radiation injury which is conveniently available for study. (author)

  9. Scanning electron microscopy of mouse intestinal mucosa after cobalt 60 and D-T neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hamlet, R [Belvidere Hospital, Glasgow (UK). Institute of Radiotherapeutics and Oncology; Carr, K R; Toner, P G; Nias, A H.W.

    1976-07-01

    The stem-cell population of the intestinal crypt is an important model system in experimental radiobiology. Standardized techniques have been developed to allow quantitation of the response of crypt cells to radiation injury following doses of 0 to 2 krad of D-T neutrons or /sup 60/Co ..gamma.. rays. These techniques rely on the identification of regenerating crypt cells three-and-a-half days after irradiation. The results were expressed as the number of regenerating crypts per circumference of small intestine, as determined by conventional histological examination; the more profound the injury, the smaller the the crypt count. The practical relevance of crypt-counting techniques to clinical radiotherapy is limited by their relative insensitivity; the dose levels commonly used in fractionated radiotherapy produced no detectable response. Scanning electron microscopy of the mucosal surface provided a more sensitive measure of radiation injury. The earliest detectable changes occurred at the level of 300 rad of ..gamma.. radiation, well below the threshold of the crypt-counting technique. At around 1,000 rad, where the first drop in crypt counts occurred, there were well-marked morphological changes which became more severe with increasing dose levels. Some differences have been observed between the morphological effects of ..gamma.. and neutron irradiation at points of radiobiological equivalence in terms ofCrypt counts (using RBE value of about 2). The changes observed may reflect more than the disruption of epithelial cell kinetics. Mucosal morphology is the total expression of many different biological parameters of which the regenerative ability of the crypt cells is only one. The surface microanatomy of the gut may be the most sensitive indicator of radiation injury which is conveniently available for study.

  10. Prototypes of Self-Powered Radiation Detectors Employing Intrinsic High-Energy Current (HEC) (POSTPRINT)

    Science.gov (United States)

    2016-01-01

    neutron sensi- tivities of a Pt self - powered detector ,” IEEE Trans. Nucl. Sci. 25, 292–295 (1978). 6T. A. Dellin, R. E. Huddleston, and C. J...Gamma-sensitive self - powered detectors and their use for in-core flux -mapping,” IEEE Trans. Nucl. Sci. 28, 752–757 (1981). 9E. A. Burke and J. Wall...AFCEC-CX-TY-TP-2016-0006 PROTOTYPES OF SELF - POWERED RADIATION DETECTORS EMPLOYING INTRINSIC HIGH-ENERGY CURRENT (HEC) (POSTPRINT) Piotr

  11. Self-powered enzyme micropumps

    Science.gov (United States)

    Sengupta, Samudra; Patra, Debabrata; Ortiz-Rivera, Isamar; Agrawal, Arjun; Shklyaev, Sergey; Dey, Krishna K.; Córdova-Figueroa, Ubaldo; Mallouk, Thomas E.; Sen, Ayusman

    2014-05-01

    Non-mechanical nano- and microscale pumps that function without the aid of an external power source and provide precise control over the flow rate in response to specific signals are needed for the development of new autonomous nano- and microscale systems. Here we show that surface-immobilized enzymes that are independent of adenosine triphosphate function as self-powered micropumps in the presence of their respective substrates. In the four cases studied (catalase, lipase, urease and glucose oxidase), the flow is driven by a gradient in fluid density generated by the enzymatic reaction. The pumping velocity increases with increasing substrate concentration and reaction rate. These rechargeable pumps can be triggered by the presence of specific analytes, which enables the design of enzyme-based devices that act both as sensor and pump. Finally, we show proof-of-concept enzyme-powered devices that autonomously deliver small molecules and proteins in response to specific chemical stimuli, including the release of insulin in response to glucose.

  12. Self-powered radiation detectors

    International Nuclear Information System (INIS)

    Gillies, Wallace.

    1980-01-01

    This invention aims to create a self fed radiation detector comprising a long central emitter-conductor absorbing the neutrons, wrapped in an insulating material, and a thin collector-conductor placed coaxially around the emitter and the insulation, the emitter being constructed of several stranded cables in a given conducting material so that the detector is flexible enough [fr

  13. Biological fate of cobalt-60 released during the corrosion of neutron-activated stanless steel in seawater

    International Nuclear Information System (INIS)

    Young, J.S.

    1982-03-01

    Passing seawater over radioactive Type 347 stainless steel in a sediment/seawater laboratory system and exposing marine animals to this environment provided information on the bioaccumulation of 60 Co from radioactive structural material. Exposure of marine organisms to radioactive corrosion products and directly to radioactive stainless steel in seawater simulated some of the possible conditions which could arise from the deposition of radioactive stainless steel on the ocean floor. Detectable levels of 60 Co in marine animals were not observed on a short term basis (5 weeks). Longterm (13 months) exposure of marine animals in a sediment/seawater system resulted in 60 Co bioaccumulation. The specific activity of 60 Co in the organisms was as much as one million times less than that initially present in the radioactive stainless steel. This was due to the dilution of 60 Co by stable cobalt in the seawater, sediments and organisms. As expected the 60 Co specific activity of the organisms never increased above that of the radioactive source. This is because 60 Co is chemicaly indistinguishable from stable Co. Increasing 60 Co concentration factors with decreasing 60 Co concentrations in the seawater and sediment media coupled with relatively constant 60 Co specific activities suggest a possible homeostatic control of cobalt concentrations in certain marine organisms. The evidence indicates that the marine animals derived more of the accumulated 60 Co from the sediments and interstitial water than from seawater. Cobalt-60 concentration factors were generally found to be lower than published cobalt concentration factors due to the predominantly insoluble nature of the corrosion products. Baseline information is provided on trace element concentrations in deep-sea organisms. Stable Co and twenty other elements were measured in abyssal invertebrates and a fish

  14. Nanogenerators for Self-Powered Gas Sensing

    Science.gov (United States)

    Wen, Zhen; Shen, Qingqing; Sun, Xuhui

    2017-10-01

    Looking toward world technology trends over the next few decades, self-powered sensing networks are a key field of technological and economic driver for global industries. Since 2006, Zhong Lin Wang's group has proposed a novel concept of nanogenerators (NGs), including piezoelectric nanogenerator and triboelectric nanogenerator, which could convert a mechanical trigger into an electric output. Considering motion ubiquitously exists in the surrounding environment and for any most common materials used every day, NGs could be inherently served as an energy source for our daily increasing requirements or as one of self-powered environmental sensors. In this regard, by coupling the piezoelectric or triboelectric properties with semiconducting gas sensing characterization, a new research field of self-powered gas sensing has been proposed. Recent works have shown promising concept to realize NG-based self-powered gas sensors that are capable of detecting gas environment without the need of external power sources to activate the gas sensors or to actively generate a readout signal. Compared with conventional sensors, these self-powered gas sensors keep the approximate performance. Meanwhile, these sensors drastically reduce power consumption and additionally reduce the required space for integration, which are significantly suitable for the wearable devices. This paper gives a brief summary about the establishment and latest progress in the fundamental principle, updated progress and potential applications of NG-based self-powered gas sensing system. The development trend in this field is envisaged, and the basic configurations are also introduced.

  15. Neutron activation analysis of some trace elements (selenium, chromium, cobalt and nickel) in the blood of vitiligo patients

    International Nuclear Information System (INIS)

    Teherani, D.K.

    1986-01-01

    Samples of full blood of vitiligo patients and those of control persons were analyzed for Se, Cr, Co and Ni contents by neutron activation analysis. The concentrations are reported in ppm/dry weight. The results showed that the Se and Co levels were significantly higher in the blood of vitiligo patients while the increase of Cr and Ni was not significant as compared to the controls. (author)

  16. Sensitivity change of rhodium self -powered detectors with burn-up

    International Nuclear Information System (INIS)

    Girgis, R.; Akimov, I.S.; Hamouda, I.

    1976-01-01

    The scope of the present paper is to obtain the calculation formulae to evaluate the rate of sensitivity change of the neutron self-powered detectors with burn-up. A code written in FORTRAN 4 was developed to be operational on the IBM-1130 computer. It has been established in the case of rhodium detectors that neglecting the β-particle absorption in the calculations leads to the underestimation of the detector sensitivity decrease up to 40%. The derived formulae can be used for other self-powered detectors. (author)

  17. Self-Powered Sun Sensor Microsystems

    NARCIS (Netherlands)

    Wu, H.; Emadi, A.; Graaf, G. de; Leijtens, J.A.P.; Wolffenbuttel, R.F.

    2009-01-01

    An analog sun sensor has been designed based on shade profile proportional to the angle of incidence of incoming light projected onto a 2×2 array of photodiodes. This concept enables an autonomous self-powered optical system with two the main functions (electrical power generation for the amplifier

  18. Structure of a carbon monoxide adduct of cobalt-exchanged zeolite A (Co/sub 5.25/Na/sub 1.5/-A x 1.5CO) by neutron profile refinement

    International Nuclear Information System (INIS)

    Adams, J.M.; Haselden, D.A.

    1984-01-01

    The structure of a carbon monoxide adduct of cobalt-exchanged zeolite A, Co/sub 5.25/Na/sub 1.5/-A x 1.5CO, has been determined by Rietveld neutron profile refinement. All exchangeable cations are located in sites adjacent to the 6-ring; 3.75 of the cobalt cations sit 0.4 A inside the β-cage (Co(2)) and are arranged tetrahedrally about the eight 6-rings sites in the β-cage. The sodium cations (Na(1)) reside just inside the α-cage in sites similar to those found previously for zeolites 3A, 4A, and 5A. The remaining 1.5 cobalt cations (Co(1)) are located in sites similar to those for sodium, but they are also coordinated to the carbon monoxide molecules, which lie on, or close-to, the threefold axis which passes through the 6-ring. Inside the β-cage there is a tetrahedral aluminum complex of AlO 4 type, the oxygen atoms (O*) of which point toward six rings not occupied by cobalt cations, Co(2). Each of the oxygen atoms of this complex is involved in a hydrogen bond (2.83 A) to the 6-ring oxygen O(3). Approximately 2/3 of these bonds are of type O*-H ... O(3) and 1/3 of type O* ...H-O(3)

  19. EPRTM Reactor neutron instrumentation

    International Nuclear Information System (INIS)

    Pfeiffer, Maxime; SALA, Stephanie

    2013-06-01

    The core safety during operation is linked, in particular, to the respect of criteria related to the heat generated in fuel rods and to the heat exchange between the rods and the coolant. This local power information is linked to the power distribution in the core. In order to evaluate the core power distribution, the EPR TM reactor relies on several types of neutron detectors: - ionization chambers located outside the vessel and used for protection and monitoring - a fixed in-core instrumentation based on Cobalt Self Powered Neutron Detectors used for protection and monitoring - a mobile reference in-core instrumentation based on Vanadium aero-balls This document provides a description of this instrumentation and its use in core protection, limitation, monitoring and control functions. In particular, a description of the detectors and the principles of their signal generation is supplied as well as the description of the treatments related to these detectors in the EPR TM reactor I and C systems (including periodical calibration). (authors)

  20. Feasibility Study for Cobalt Bundle Loading to CANDU Reactor Core

    International Nuclear Information System (INIS)

    Park, Donghwan; Kim, Youngae; Kim, Sungmin

    2016-01-01

    CANDU units are generally used to produce cobalt-60 at Bruce and Point Lepreau in Canada and Embalse in Argentina. China has started production of cobalt-60 using its CANDU 6 Qinshan Phase III nuclear power plant in 2009. For cobalt-60 production, the reactor’s full complement of stainless steel adjusters is replaced with neutronically equivalent cobalt-59 adjusters, which are essentially invisible to reactor operation. With its very high neutron flux and optimized fuel burn-up, the CANDU has a very high cobalt-60 production rate in a relatively short time. This makes CANDU an excellent vehicle for bulk cobalt-60 production. Several studies have been performed to produce cobalt-60 using adjuster rod at Wolsong nuclear power plant. This study proposed new concept for producing cobalt-60 and performed the feasibility study. Bundle typed cobalt loading concept is proposed and evaluated the feasibility to fuel management without physics and system design change. The requirement to load cobalt bundle to the core was considered and several channels are nominated. The production of cobalt-60 source is very depend on the flux level and burnup directly. But the neutron absorption characteristic of cobalt bundle is too high, so optimizing design study is needed in the future

  1. Feasibility Study for Cobalt Bundle Loading to CANDU Reactor Core

    Energy Technology Data Exchange (ETDEWEB)

    Park, Donghwan; Kim, Youngae; Kim, Sungmin [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    CANDU units are generally used to produce cobalt-60 at Bruce and Point Lepreau in Canada and Embalse in Argentina. China has started production of cobalt-60 using its CANDU 6 Qinshan Phase III nuclear power plant in 2009. For cobalt-60 production, the reactor’s full complement of stainless steel adjusters is replaced with neutronically equivalent cobalt-59 adjusters, which are essentially invisible to reactor operation. With its very high neutron flux and optimized fuel burn-up, the CANDU has a very high cobalt-60 production rate in a relatively short time. This makes CANDU an excellent vehicle for bulk cobalt-60 production. Several studies have been performed to produce cobalt-60 using adjuster rod at Wolsong nuclear power plant. This study proposed new concept for producing cobalt-60 and performed the feasibility study. Bundle typed cobalt loading concept is proposed and evaluated the feasibility to fuel management without physics and system design change. The requirement to load cobalt bundle to the core was considered and several channels are nominated. The production of cobalt-60 source is very depend on the flux level and burnup directly. But the neutron absorption characteristic of cobalt bundle is too high, so optimizing design study is needed in the future.

  2. Calculating the Responses of Self-Powered Radiation Detectors.

    Science.gov (United States)

    Thornton, D. A.

    Available from UMI in association with The British Library. The aim of this research is to review and develop the theoretical understanding of the responses of Self -Powered Radiation Detectors (SPDs) in Pressurized Water Reactors (PWRs). Two very different models are considered. A simple analytic model of the responses of SPDs to neutrons and gamma radiation is presented. It is a development of the work of several previous authors and has been incorporated into a computer program (called GENSPD), the predictions of which have been compared with experimental and theoretical results reported in the literature. Generally, the comparisons show reasonable consistency; where there is poor agreement explanations have been sought and presented. Two major limitations of analytic models have been identified; neglect of current generation in insulators and over-simplified electron transport treatments. Both of these are developed in the current work. A second model based on the Explicit Representation of Radiation Sources and Transport (ERRST) is presented and evaluated for several SPDs in a PWR at beginning of life. The model incorporates simulation of the production and subsequent transport of neutrons, gamma rays and electrons, both internal and external to the detector. Neutron fluxes and fuel power ratings have been evaluated with core physics calculations. Neutron interaction rates in assembly and detector materials have been evaluated in lattice calculations employing deterministic transport and diffusion methods. The transport of the reactor gamma radiation has been calculated with Monte Carlo, adjusted diffusion and point-kernel methods. The electron flux associated with the reactor gamma field as well as the internal charge deposition effects of the transport of photons and electrons have been calculated with coupled Monte Carlo calculations of photon and electron transport. The predicted response of a SPD is evaluated as the sum of contributions from individual

  3. Contribution to the replacement of cobalt-free hardfacing coating by laser cladding in fast neutron reactors

    International Nuclear Information System (INIS)

    De-Tran, Van

    2014-01-01

    This thesis contributes to the replacement of the coating of Stellite 6 which is used in friction areas for the primary circuit of the fast neutron reactor. It contains three parts: 1) A literature review for selecting the materials and the deposition process 2) A parametric study to get healthy deposits (good adhesion with the substrate, little porosity, no cracks, low dilution) 3) A study wear behavior of deposits obtained, at high temperature (200 C) under an atmosphere inert gas, to determine the wear resistance of materials selected without the influence of an eventual oxidation layer. From the literature review, it appears the following choices implemented in our study: * the method laser cladding with advantages such as: - Good adhesion (metallurgical) - High cooling speed - Low dilution rate - Wide parametric range * two nickel-based alloys: Colmonoy-52 and Tribaloy-700. These alloys have good dry wear behavior and could be deposited by the laser. In the manufacturing part of the healthy deposit, firstly, we characterized the metal powder. Then, a parametric study was performed to look for a good parametric range that makes us getting a healthy deposit of Stellite 6 (reference) of Colmonoy-52 and Tribaloy-700. In this case, relationships among three main process parameters laser cladding (laser beam power, surface scanning speed, rate of powder) with the microstructure and chemical composition of the deposit are studied. In study the wear behavior, a pin-on-disc type of tribological was used and tests were carried out in argon at room temperature and 200 C. We investigated the wear mechanism of the best deposition of Stellite 6, Colmonoy-52 and Tribaloy-700. The wear resistance of these materials were thoroughly compared. (author) [fr

  4. Self-Powered Electrochemical Lactate Biosensing

    Directory of Open Access Journals (Sweden)

    Ankit Baingane

    2017-10-01

    Full Text Available This work presents the development and characterization of a self-powered electrochemical lactate biosensor for real-time monitoring of lactic acid. The bioanode and biocathode were modified with D-lactate dehydrogenase (D-LDH and bilirubin oxidase (BOD, respectively, to facilitate the oxidation and reduction of lactic acid and molecular oxygen. The bioelectrodes were arranged in a parallel configuration to construct the biofuel cell. This biofuel cell’s current–voltage characteristic was analyzed in the presence of various lactic acid concentrations over a range of 1–25 mM. An open circuit voltage of 395.3 mV and a short circuit current density of 418.8 µA/cm² were obtained when operating in 25 mM lactic acid. Additionally, a 10 pF capacitor was integrated via a charge pump circuit to the biofuel cell to realize the self-powered lactate biosensor with a footprint of 1.4 cm × 2 cm. The charge pump enabled the boosting of the biofuel cell voltage in bursts of 1.2–1.8 V via the capacitor. By observing the burst frequency of a 10 pF capacitor, the exact concentration of lactic acid was deduced. As a self-powered lactate sensor, a linear dynamic range of 1–100 mM lactic acid was observed under physiologic conditions (37 °C, pH 7.4 and the sensor exhibited an excellent sensitivity of 125.88 Hz/mM-cm2. This electrochemical lactate biosensor has the potential to be used for the real-time monitoring of lactic acid level in biological fluids.

  5. An Optical Model Study of Neutrons Elastically Scattered by Iron, Nickel, Cobalt, Copper, and Indium in the Energy Region 1.5 to 7.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Holmqvist, B; Wiedling, T

    1967-03-15

    Angular distributions of elastically scattered neutrons have been measured for cobalt and copper at nine energies between 1.5 and 7.0 MeV, for natural iron at 4.6 MeV, for natural nickel and indium at four energies between 3.0 and 4.6 MeV, by using time-of-flight technique. The observed angular distributions were corrected for neutron flux attenuation, multiple elastic scattering, and the finite geometry of the source-sample-detector system by using a Monte Carlo program. Theoretical angular distributions have been fitted to the experimental angular distributions by using an optical model potential with Saxon-Woods form factors. A computer program was used to find parameter values of the potential giving the best fittings to the experimental angular distributions.

  6. Cobalt-60 production in CANDU reactors

    International Nuclear Information System (INIS)

    Ross, Michel; Lemire, Christian

    2002-01-01

    CANDU reactors can produce cobalt-60 very efficiently and with an interesting return on investment. This paper discusses what is needed to convert a CANDU reactor into a cobalt-60 producer: what are the different phases, the safety studies required, the physical modifications needed, and what is the minimum involvement of the utility owning the plant. The past ten years of experience of Hydro-Quebec as a cobalt-60 producer will be reviewed, including the management of the risk of both incident and electricity generation loss, and including the benefits for the utility and its personnel. Originally a simple metal used for centuries as a pigment, cobalt-59 today is transformed into cobalt-60, a radioactive element of unprecedented value. Well known in medicine for cancer treatment, cobalt-60 is also used to sterilize a wide range of disposable medical products used in hospitals and to sanitize pharmaceutical and cosmetic products. Cobalt-60 is proving to be a new and effective solution, in the food sector, for preserving harvests and controlling food-borne diseases, or to advantageously replace certain gases and chemical products which are suspected of being harmful or carcinogenic. There are also other applications, such as: hardening of some plastics, treatment of sewage sludge and elimination of harmful insect populations. With a half-life of 5,3 years, cobalt-60 is a metal not found in nature. It is a radioactive isotope produced by exposing stable nuclei of cobalt-59 to neutrons. One of the best places to find such an important neutron source is a nuclear reactor. High energy gamma rays are then emitted during the process of radioactive decay, where cobalt-60 seeks again its stable state

  7. A Self-Powered Thin-Film Radiation Detector Using Intrinsic High-Energy Current (HEC) (Author’s Final Version)

    Science.gov (United States)

    2016-09-08

    of electromagnetic 85 pulse effects on cables and electrical devices4 and as a self - powered detector for in-core neutron flux measurement in nuclear...AFCEC-CX-TY-TP-2016-0003 A SELF - POWERED THIN-FILM RADIATION DETECTOR USING INTRINSIC HIGH-ENERGY CURRENT (HEC) (AUTHOR’S FINAL VERSION...14 -- 5 Oct 15 A self - powered thin-film radiation detector using intrinsic high-energy current (HEC) (Author’s Final Version) FA8051-15-P-0010

  8. Recent advances in self-powered flux detector development for CANDU reactors

    International Nuclear Information System (INIS)

    Allan, C.J.; Drewell, N.H.; Hall, D.S.

    1983-01-01

    The characteristics of self-powered flux detectors used in CANDU reactors are reviewed. Detectors with emitters of vanadium, platinum, platinum-clad Inconel and Inconel are used. Data on dynamic response, relative neutron and gamma-ray sensitivities, and burnout, obtained both from experiments and from the Monte Carlo code ICARES, are presented. Since the response of a detector depends on the relative magnitudes of the various current-producing mechanisms, the operating principles of self-powered detectors are briefly reviewed. Current research programmes are discussed. These include modifying the design of the platinum-clad Inconel detector in order to match its dynamic response to that of the fuel power and developing a prompt-responding flux-mapping detector. (author)

  9. Cobalt-60 production in CANDU power reactors

    International Nuclear Information System (INIS)

    Malkoske, G.R.; Norton, J.L.; Slack, J.

    2002-01-01

    MDS Nordion has been supplying cobalt-60 sources to industry for industrial and medical purposes since 1946. These cobalt-60 sources are used in many market and product segments, but are primarily used to sterilize single-use medical products including; surgical kits, gloves, gowns, drapes, and cotton swabs. Other applications include sanitization of cosmetics, microbial reduction of pharmaceutical raw materials, and food irradiation. The technology for producing the cobalt-60 isotope was developed by MDS Nordion and Atomic Energy of Canada Limited (AECL) almost 55 years ago using research reactors at the AECL Chalk River Laboratories in Ontario, Canada. The first cobalt-60 source produced for medical applications was manufactured by MDS Nordion and used in cancer therapy. The benefits of cobalt-60 as applied to medical product manufacturing, were quickly realized and the demand for this radioisotope quickly grew. The same technology for producing cobalt-60 in research reactors was then designed and packaged such that it could be conveniently transferred to a utility/power reactor. In the early 1970's, in co-operation with Ontario Power Generation (formerly Ontario Hydro), bulk cobalt-60 production for industrial irradiation applications was initiated in the four Pickering A CANDU reactors. As the demand and acceptance of sterilization of medical products grew, MDS Nordion expanded its bulk supply by installing the proprietary Canadian technology for producing cobalt-60 in additional CANDU reactors. CANDU is unique among the power reactors of the world, being heavy water moderated and fuelled with natural uranium. They are also designed and supplied with stainless steel adjusters, the primary function of which is to shape the neutron flux to optimize reactor power and fuel bum-up, and to provide excess reactivity needed to overcome xenon-135 poisoning following a reduction of power. The reactor is designed to develop full power output with all of the adjuster

  10. Mathematical model of rhodium self-powered detectors and algorithms for correction of their time delay

    International Nuclear Information System (INIS)

    Bur'yan, V.I.; Kozlova, L.V.; Kuzhil', A.S.; Shikalov, V.F.

    2005-01-01

    The development of algorithms for correction of self-powered neutron detector (SPND) inertial is caused by necessity to increase the fast response of the in-core instrumentation systems (ICIS). The increase of ICIS fast response will permit to monitor in real time fast transient processes in the core, and in perspective - to use the signals of rhodium SPND for functions of emergency protection by local parameters. In this paper it is proposed to use mathematical model of neutron flux measurements by means of SPND in integral form for creation of correction algorithms. This approach, in the case, is the most convenient for creation of recurrent algorithms for flux estimation. The results of comparison for estimation of neutron flux and reactivity by readings of ionization chambers and SPND signals, corrected by proposed algorithms, are presented [ru

  11. Comparison of the effects of 50 MeV/sub d → Be/ neutron and cobalt-60 irradiation of the kidneys of Rhesus monkeys

    International Nuclear Information System (INIS)

    Raulston, G.L.; Gray, K.N.; Gleiser, C.A.; Jardine, J.H.; Flow, B.L.; Huchton, J.I.; Bennett, K.R.; Hussey, D.H.

    1978-01-01

    Twenty rhesus monkeys had one kidney irradiated (after undergoing unilateral nephrectomies) with one of four doses: 960 or 1080 rads of 50 MeV/sub d→Be/ neutrons, or 2350 or 2700 rads of 60 Co. Whereas animals treated with the lower dose of neutrons or 60 Co are alive with relatively normal renal function, those treated with the higher dose of neutrons died of radiation nephritis. Animals treated with the higher dose of 60 Co developed radiation nephritis but survived. The physiological and histopathological changes of radiation nephritis secondary to neutron irradiation are not qualitatively different from those reported for radiation nephritis secondary to photon irradiation

  12. Research on self-powered detectors for gamma-ray monitoring

    International Nuclear Information System (INIS)

    Cho, S.W.; Lee, Y.J.

    1984-01-01

    Self-powered neutron detectors are used extensively in power reactors both for flux mapping and for power control and over-power protection, because of their small size, ruggedness and simplicity. But they have a few disadvantages such as high burn-up rate and background signal produced by the gamma-rays from the reactor itself. In order to overcome these disadvantages and to achieve a better understanding of gamma-ray effects of self-power detectors, a new type of self-powered detectors was designed and fabricated by the author,and experiments have carried out in the 10kCi sup(60)Co gamma irradiation facility in Korea Advanced Energy Research Institute. The configuration of the new type detectors is not of coaxial type but of paralled plate in order to obtain directional effects of gamma-ray incidence. Detector materials and dimensions are so chosen that the output current signal is large enough to be detected using some commercial measuring divice even at low dose rate and the contribution of the lead cable to the total signal is negligibly small. The results are 1)sensitivity is depended primarily on the materials of the insulator, 2)output signal has a good linearity to gamma dose rate, 3) response of detectors is prompt, but not perfect, 4) critical thickness for satusation of the output current is thinner than the range of photoelectron in the materials. (Author)

  13. Research on self-powered detectors for gamma-ray monitoring

    International Nuclear Information System (INIS)

    Cho, S.W.

    1983-01-01

    Self-powered neutron detectors are used extensively in power reactors both for flux mapping and for power control and over-power protection, because of their small size, ruggedness and simplicity. But they have a few disadvantages such as high burn-up rate and background signal produced by the gamma-rays from the reactor itself. In order to overcome these disadvantages and to achieve a better understanding of gamma-ray effects of self-powered detectors, a new type of self-powered detectors was designed and fabricated by the author, and experiments have been carried out in the 10kCi sup(60)Co gamma irradiation facility in Korea Advanced Energy Research Institute. The configuration of the new type detectors is not of coaxial type but of paralled plate in order to obtain directional effects of gamma-ray incidence. Detector materials and dimensions are so chosen that the output current signal is large enough to be detected using some commercial measuring divice even at low dose rate and the contribution of the lead cable to the totel signal is negligibly small. The results are 1) sensitivity is depended primarily on the materials of the insulator, 2) output signal has a good linearity to gamma dose rate, 3) response of detectors is prompt, but not perfect, 4) critical thickness for satusation of the output current is thinner than the range of photoelectron in the materials. (Author) πT

  14. The Self-Powered Detector Simulation `MATiSSe' Toolbox applied to SPNDs for severe accident monitoring in PWRs

    Science.gov (United States)

    Barbot, Loïc; Villard, Jean-François; Fourrez, Stéphane; Pichon, Laurent; Makil, Hamid

    2018-01-01

    In the framework of the French National Research Agency program on nuclear safety and radioprotection, the `DIstributed Sensing for COrium Monitoring and Safety' project aims at developing innovative instrumentation for corium monitoring in case of severe accident in a Pressurized Water nuclear Reactor. Among others, a new under-vessel instrumentation based on Self-Powered Neutron Detectors is developed using a numerical simulation toolbox, named `MATiSSe'. The CEA Instrumentation Sensors and Dosimetry Lab developed MATiSSe since 2010 for Self-Powered Neutron Detectors material selection and geometry design, as well as for their respective partial neutron and gamma sensitivity calculations. MATiSSe is based on a comprehensive model of neutron and gamma interactions which take place in Selfpowered neutron detector components using the MCNP6 Monte Carlo code. As member of the project consortium, the THERMOCOAX SAS Company is currently manufacturing some instrumented pole prototypes to be tested in 2017. The full severe accident monitoring equipment, including the standalone low current acquisition system, will be tested during a joined CEA-THERMOCOAX experimental campaign in some realistic irradiation conditions, in the Slovenian TRIGA Mark II research reactor.

  15. Effects of single and split doses of cobalt-60 gamma rays and 14 MeV neutrons on mouse stem cell spermatogonia.

    Science.gov (United States)

    Hacker-Klom, U B; Köhnlein, W; Göhde, W

    2000-12-01

    The long-term effects of ionizing radiation on male gonads may be the result of damage to spermatogonial stem cells. Doses of 10 cGy to 15 Gy (60)Co gamma rays or 10 cGy to 7 Gy 14 MeV neutrons were given to NMRI mice as single or split doses separated by a 24-h interval. The ratios of haploid spermatids/2c cells and the coefficients of variation of DNA histogram peaks as measures of both the cytocidal and the clastogenic actions of radiation were analyzed by DNA flow cytometry after DAPI staining. The coefficient of variation is not only a statistical examination of the data but is also used here as a measure of residual damage to DNA (i.e. a biological dosimeter). Testicular histology was examined in parallel. At 70 days after irradiation, the relative biological effectiveness for neutrons at 50% survival of spermatogonial stem cells was 3.6 for single doses and 2.8 for split doses. The average coefficient of variation of unirradiated controls of elongated spermatids was doubled when stem cells were irradiated with single doses of approximately 14 Gy (60)Co gamma rays or 3 Gy neutrons and observed 70 days later. Split doses of (60)Co gamma rays were more effective than single doses, doubling DNA dispersion at 7 Gy. No fractionation effect was found with neutrons with coefficients of variation.

  16. Studies on Flat Sandwich-type Self-Powered Detectors for Flux Measurements in ITER Test Blanket Modules

    Science.gov (United States)

    Raj, Prasoon; Angelone, Maurizio; Döring, Toralf; Eberhardt, Klaus; Fischer, Ulrich; Klix, Axel; Schwengner, Ronald

    2018-01-01

    Neutron and gamma flux measurements in designated positions in the test blanket modules (TBM) of ITER will be important tasks during ITER's campaigns. As part of the ongoing task on development of nuclear instrumentation for application in European ITER TBMs, experimental investigations on self-powered detectors (SPD) are undertaken. This paper reports the findings of neutron and photon irradiation tests performed with a test SPD in flat sandwich-like geometry. Whereas both neutrons and gammas can be detected with appropriate optimization of geometries, materials and sizes of the components, the present sandwich-like design is more sensitive to gammas than 14 MeV neutrons. Range of SPD current signals achievable under TBM conditions are predicted based on the SPD sensitivities measured in this work.

  17. EFTF cobalt test assembly results

    International Nuclear Information System (INIS)

    Rawlins, J.A.; Wootan, D.W.; Carter, L.L.; Brager, H.R.; Schenter, R.E.

    1988-01-01

    A cobalt test assembly containing yttrium hydride pins for neutron moderation was irradiated in the Fast Flux Test Facility during Cycle 9A for 137.7 equivalent full power days at a power level fo 291 MW. The 36 test pins consisted of a batch of 32 pins containing cobalt metal to produce Co-60, and a set of 4 pins with europium oxide to produce Gd-153, a radioisotope used in detection of the bone disease Osteoporosis. Post-irradiation examination of the cobalt pins determined the Co-60 produced with an accuracy of about 5 %. The measured Co-60 spatially distributed concentrations were within 20 % of the calculated concentrations. The assembly average Co-60 measured activity was 4 % less than the calculated value. The europium oxide pins were gamma scanned for the europium isotopes Eu-152 and Eu-154 to an absolute accuracy of about 10 %. The measured europium radioisotpe anc Gd-153 concentrations were within 20 % of calculated values. In conclusion, the hydride assembly performed well and is an excellent vehicle for many Fast Flux Test Facility isotope production applications. The results also demonstrate that the calculational methods developed by the Westinghouse Hanford Company are very accurate. (author)

  18. Research Update: Nanogenerators for self-powered autonomous wireless sensors

    Science.gov (United States)

    Khan, Usman; Hinchet, Ronan; Ryu, Hanjun; Kim, Sang-Woo

    2017-07-01

    Largely distributed networks of sensors based on the small electronics have great potential for health care, safety, and environmental monitoring. However, in order to have a maintenance free and sustainable operation, such wireless sensors have to be self-powered. Among various energies present in our environment, mechanical energy is widespread and can be harvested for powering the sensors. Piezoelectric and triboelectric nanogenerators (NGs) have been recently introduced for mechanical energy harvesting. Here we introduce the architecture and operational modes of self-powered autonomous wireless sensors. Thereafter, we review the piezoelectric and triboelectric NGs focusing on their working mechanism, structures, strategies, and materials.

  19. Cobalt-60 production in CANDU power reactors

    International Nuclear Information System (INIS)

    Slack, J.; Norton, J.L.; Malkoske, G.R.

    2003-01-01

    MDS Nordion has been supplying cobalt-60 sources to industry for industrial and medical purposes since 1946. These cobalt-60 sources are used in many market and product segments. The major application is in the health care industry where irradiators are used to sterilize single use medical products. These irradiators are designed and built by MDS Nordion and are used by manufacturers of surgical kits, gloves, gowns, drapes and other medical products. The irradiator is a large shielded room with a storage pool for the cobalt-60 sources. The medical products are circulated through the shielded room and exposed to the cobalt-60 sources. This treatment sterilizes the medical products which can then be shipped to hospitals for immediate use. Other applications for this irradiation technology include sanitisation of cosmetics, microbial reduction of pharmaceutical raw materials and food irradiation. The cobalt-60 sources are manufactured by MDS Nordion in their Cobalt Operations Facility in Kanata. More than 75,000 cobalt-60 sources for use in irradiators have been manufactured by MDS Nordion. The cobalt-60 sources are double encapsulated in stainless steel capsules, seal welded and helium leak tested. Each source may contain up to 14,000 curies. These sources are shipped to over 170 industrial irradiators around the world. This paper will focus on the MDS Nordion proprietary technology used to produce the cobalt-60 isotope in CANDU reactors. Almost 55 years ago MDS Nordion and Atomic Energy of Canada developed the process for manufacturing cobalt-60 at the Chalk River Labs, in Ontario, Canada. A cobalt-59 target was introduced into a research reactor where the cobalt-59 atom absorbed one neutron to become cobalt-60. Once the cobalt-60 material was removed from the research reactor it was encapsulated in stainless steel and seal welded using a Tungsten Inert Gas weld. The first cobalt-60 sources manufactured using material from the Chalk River Labs were used in cancer

  20. Cobalt release from inexpensive jewellery

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Jellesen, Morten Stendahl; Menné, Torkil

    2010-01-01

    . Conclusions: This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future......Objectives: The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. Methods: The cobalt spot test was used to assess cobalt release from all items...

  1. A Self-Powered Insole for Human Motion Recognition

    Directory of Open Access Journals (Sweden)

    Yingzhou Han

    2016-09-01

    Full Text Available Biomechanical energy harvesting is a feasible solution for powering wearable sensors by directly driving electronics or acting as wearable self-powered sensors. A wearable insole that not only can harvest energy from foot pressure during walking but also can serve as a self-powered human motion recognition sensor is reported. The insole is designed as a sandwich structure consisting of two wavy silica gel film separated by a flexible piezoelectric foil stave, which has higher performance compared with conventional piezoelectric harvesters with cantilever structure. The energy harvesting insole is capable of driving some common electronics by scavenging energy from human walking. Moreover, it can be used to recognize human motion as the waveforms it generates change when people are in different locomotion modes. It is demonstrated that different types of human motion such as walking and running are clearly classified by the insole without any external power source. This work not only expands the applications of piezoelectric energy harvesters for wearable power supplies and self-powered sensors, but also provides possible approaches for wearable self-powered human motion monitoring that is of great importance in many fields such as rehabilitation and sports science.

  2. Effect of cobalt-60 γ radiation and of thermal neutrons on high resistance P and N silicon. Possibility of obtaining a nuclear compensation for P type silicon

    International Nuclear Information System (INIS)

    Messier, J.

    1965-11-01

    Type P silicon has been compensated by the production of a controlled and uniform amount of donor atoms ( 31 P) using thermal neutrons to bring about a nuclear transformation. It is shown that it is possible in this way to reduce by a factor of about one hundred the overall concentration of residual ionised impurities in the purest crystals obtained by floating zone purification (2 x 10 12 atoms/cm 3 ). The degree compensation obtained is limited by the initial inhomogeneity of acceptor impurities which have to be compensated. Lattice defects which still remain after prolonged annealings reduce the life-time of the material to about 10 μs approximately. Particle detectors having thicknesses of 2 to 5 mm have been built by this process; they give good results, particularly at low temperatures. A study has also been made of the number and of the nature of lattice defects produced by thermal neutrons in high resistivity P and N type crystals. These defects have been compared to those produced by γ rays from 60 Co. A discussion is given of the validity of the Wertheim model concerning pronounced recombination at low temperatures (77 deg. K - 300 deg. K) of primary defect-interstitial pairs. The nature of the defects introducing energy levels into the lower half of the forbidden band has been studied. (author) [fr

  3. Sensitivity of self-powered detector probes to electron and gamma-ray fields

    Energy Technology Data Exchange (ETDEWEB)

    Lone, M A; Wong, P Y [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1996-12-31

    A self-powered detector (SPD) is a simple, passive device that consists of a coaxial probe with a metallic outer sleeve, a mineral oxide insulating layer, and a metallic inner core. SPD`s are used in nuclear reactors to monitor neutron and gamma fields. Responses of SPD`s to electrons and {gamma}-rays of various energies were investigated with Monte Carlo simulations. Transmission filters were studied for the design of threshold SPD probes used for online monitoring of the energy spectrum of high-power industrial electron accelerator beams. Filters were also investigated for the enhancement of {gamma}-ray sensitivity of an SPD placed in a mixed electron and {gamma}-ray field. (author). 30 refs., 1 tab., 8 figs.

  4. Sensitivity of self-powered detector probes to electron and gamma-ray fields

    International Nuclear Information System (INIS)

    Lone, M.A.; Wong, P.Y.

    1995-01-01

    A self-powered detector (SPD) is a simple, passive device that consists of a coaxial probe with a metallic outer sleeve, a mineral oxide insulating layer, and a metallic inner core. SPD's are used in nuclear reactors to monitor neutron and gamma fields. Responses of SPD's to electrons and γ-rays of various energies were investigated with Monte Carlo simulations. Transmission filters were studied for the design of threshold SPD probes used for online monitoring of the energy spectrum of high-power industrial electron accelerator beams. Filters were also investigated for the enhancement of γ-ray sensitivity of an SPD placed in a mixed electron and γ-ray field. (author). 30 refs., 1 tab., 8 figs

  5. Self-powered wireless disposable sensor for welfare application.

    Science.gov (United States)

    Douseki, Takakuni; Tanaka, Ami

    2013-01-01

    A self-powered urinary incontinence sensor consisting of a flexible urine-activated battery and a wireless transmitter has been developed as an application for wireless biosensor networks. The flexible urine-activated battery is embedded in a disposal diaper and makes possible both the sensing of urine leakage and self-powered operation. An intermittent power-supply circuit that uses an electric double-layer capacitor (EDLC) with a small internal resistance suppresses the supply voltage drop due to the large internal resistance of the battery. This circuit supplies the power to a wireless transmitter. A 315-MHz-band wireless transmitter performs low-power operation. To verify the effectiveness of the circuit scheme, we fabricated a prototype sensor system. When 80 cc of urine is poured onto the diaper, the battery outputs a voltage of 1 V; and the sensor can transmit an ID signal over a distance of 5 m.

  6. Paper-based supercapacitors for self-powered nanosystems.

    Science.gov (United States)

    Yuan, Longyan; Xiao, Xu; Ding, Tianpeng; Zhong, Junwen; Zhang, Xianghui; Shen, Yue; Hu, Bin; Huang, Yunhui; Zhou, Jun; Wang, Zhong Lin

    2012-05-14

    Energy storage on paper: paper-based, all-solid-state, and flexible supercapacitors were fabricated, which can be charged by a piezoelectric generator or solar cells and then discharged to power a strain sensor or a blue-light-emitting diode, demonstrating its efficient energy management in self-powered nanosystems. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Beta- and gamma-decay studies of neutron-rich chromium, manganese, cobalt and nickel isotopes including the new isotopes 60Cr and 60gMn

    International Nuclear Information System (INIS)

    Bosch, U.; Schmidt-Ott, W.D.; Runte, E.; Tidemand-Petersson, P.; Koschel, P.; Meissner, F.; Kirchner, R.; Klepper, O.; Roeckl, E.; Rykaczewski, K.; Schardt, D.

    1987-10-01

    A 36 mg/cm 2 thick nat W target was irradiated with 11.5 MeV/u 76 Ge of 15 to 20 particle + nA beam intensity. On-line mass-separated samples of projectile-like neutron-rich products from multi-nucleon transfer-reactions were investigated in the region of mass 58-69 by β- and γ-ray spectroscopy. The new isotope 60 Cr was identified with a half-life of 0.57(6) s and for the 60 Mn ground-state a half-life value of 51(6) s was obtained. Decay schemes were constructed for 58 Cr, 58 Mn (t 1/2 = 3 s), 65,66,67 Co and 69 Ni. One new γ-ray was found in the decay of 59 Cr. The Q β -value of 66 Co was measured yielding 9.7(5) MeV. The comparison of the measured new β-half-life of 60 Cr with the most recent predictions gave again an enhancement of the experimental value. (orig.)

  8. Cobalt sensitization and dermatitis

    DEFF Research Database (Denmark)

    Thyssen, Jacob P

    2012-01-01

    : This clinical review article presents clinical and scientific data on cobalt sensitization and dermatitis. It is concluded that cobalt despite being a strong sensitizer and a prevalent contact allergen to come up on patch testing should be regarded as a very complex metal to test with. Exposure...

  9. Self-powered detector probes for electron and gamma-ray beam monitoring in high-power industrial accelerators

    International Nuclear Information System (INIS)

    Lone, M.A.

    1992-08-01

    A self-powered detector (SPD) is a simple passive device that consists of a coaxial probe with a metallic outer sleeve, a mineral oxide insulating layer, and a metallic inner core. SPDs are used in nuclear reactors for monitoring neutron and gamma ray fields. Responses of various SPDs to electron and gamma ray beams from industrial accelerators were investigated with Monte Carlo simulations. By judicious choice of transmission filters, threshold SPD probes were investigated for on-line monitoring of the beam energy spectrum of the high-power IMPELA industrial electron accelerator. (Author) (14 figs, 16 refs.)

  10. Elicitation threshold of cobalt chloride

    DEFF Research Database (Denmark)

    Fischer, Louise A; Johansen, Jeanne D; Voelund, Aage

    2016-01-01

    : On the basis of five included studies, the ED10 values of aqueous cobalt chloride ranged between 0.0663 and 1.95 µg cobalt/cm(2), corresponding to 30.8-259 ppm. CONCLUSIONS: Our analysis provides an overview of the doses of cobalt that are required to elicit allergic cobalt contactdermatitis in sensitized...

  11. Ion exchange of Cobalt and Cadmium in Zeolite X

    International Nuclear Information System (INIS)

    Nava M, I.

    1994-01-01

    The growing development in the industry has an important contribution to the environmental damage, where the natural effluents are each day more contaminated by toxic elements, such as: mercury, chromium, lead and cadmium. So as to separate such elements it has sorbent must have enough stability, and have a sharp capacity of sorption. In this work it was studied the sorption behavior of cobalt and on the other hand, cadmium in aqueous solutions, which along with sodic form of the Zeolite X, undergoes a phenomenon of ionic interchange. Such interchange was verify to different concentration of cadmium, cobalt and hydronium ion. The content of cobalt and sodium in the interchanged samples was detected through the neutronic activation analysis. The results disclose a higher selectivity for cadmium than cobalt. (Author)

  12. Self-powered Imbibing Microfluidic Pump by Liquid Encapsulation: SIMPLE.

    Science.gov (United States)

    Kokalj, Tadej; Park, Younggeun; Vencelj, Matjaž; Jenko, Monika; Lee, Luke P

    2014-11-21

    Reliable, autonomous, internally self-powered microfluidic pumps are in critical demand for rapid point-of-care (POC) devices, integrated molecular-diagnostic platforms, and drug delivery systems. Here we report on a Self-powered Imbibing Microfluidic Pump by Liquid Encapsulation (SIMPLE), which is disposable, autonomous, easy to use and fabricate, robust, and cost efficient, as a solution for self-powered microfluidic POC devices. The imbibition pump introduces the working liquid which is sucked into a porous material (paper) upon activation. The suction of the working liquid creates a reduced pressure in the analytical channel and induces the sequential sample flow into the microfluidic circuits. It requires no external power or control and can be simply activated by a fingertip press. The flow rate can be programmed by defining the shape of utilized porous material: by using three different paper shapes with circular section angles 20°, 40° and 60°, three different volume flow rates of 0.07 μL s(-1), 0.12 μL s(-1) and 0.17 μL s(-1) are demonstrated at 200 μm × 600 μm channel cross-section. We established the SIMPLE pumping of 17 μL of sample; however, the sample volume can be increased to several hundreds of μL. To demonstrate the design, fabrication, and characterization of SIMPLE, we used a simple, robust and cheap foil-laminating fabrication technique. The SIMPLE can be integrated into hydrophilic or hydrophobic materials-based microfluidic POC devices. Since it is also applicable to large-scale manufacturing processes, we anticipate that a new chapter of a cost effective, disposable, autonomous POC diagnostic chip is addressed with this technical innovation.

  13. Method of fabricating self-powered nuclear radiation detector assemblies

    International Nuclear Information System (INIS)

    Playfoot, K.; Bauer, R.F.; Sekella, Y.M.

    1982-01-01

    In a method of fabricating a self-powered nuclear radiation detector assembly an emitter electrode wire and signal cable center wire are connected and disposed within the collector electrode tubular sheath with compressible insulating means disposed between the wires and the tubular sheath. The above assembly is reduced in diameter while elongating the tubular sheath and the emitter wire and signal cable wire. The emitter wire is reduced to a predetermined desired diameter, and is trimmed to a predetermined length. An end cap is hermetically sealed to the tubular sheath at the extending end of the emitter with insulating means between the emitter end and the end cap. (author)

  14. Self-powered integrated systems-on-chip (energy chip)

    KAUST Repository

    Hussain, Muhammad Mustafa

    2010-04-23

    In today\\'s world, consumer driven technology wants more portable electronic gadgets to be developed, and the next big thing in line is self-powered handheld devices. Therefore to reduce the power consumption as well as to supply sufficient power to run those devices, several critical technical challenges need to be overcome: a. Nanofabrication of macro/micro systems which incorporates the direct benefit of light weight (thus portability), low power consumption, faster response, higher sensitivity and batch production (low cost). b. Integration of advanced nano-materials to meet the performance/cost benefit trend. Nano-materials may offer new functionalities that were previously underutilized in the macro/micro dimension. c. Energy efficiency to reduce power consumption and to supply enough power to meet that low power demand. We present a pragmatic perspective on a self-powered integrated System on Chip (SoC). We envision the integrated device will have two objectives: low power consumption/dissipation and on-chip power generation for implementation into handheld or remote technologies for defense, space, harsh environments and medical applications. This paper provides insight on materials choices, intelligent circuit design, and CMOS compatible integration.

  15. Printed Self-Powered Miniature Air Sampling Sensors

    Directory of Open Access Journals (Sweden)

    Joseph Birmingham

    2017-07-01

    Full Text Available The recent geo-political climate has increased the necessity for autonomous, chip-sized, lightweight, air sampling systems which can quickly detect and characterize chemical, biological, radiological, nuclear, and high explosive (CBRNE hazardous materials and relay the results. To address these issues, we have developed a self-powered 3-D chip architecture that processes air to produce concentrated size- sorted particle (and vapor samples that could be integrated with on-chip nanoelectronic detectors for the discovery of weapons of mass destruction (WMD. The unique air movement approach is composed of a nanoscale energy harvester that provides electricity to a printed ion-drag pump to push air through coated-microstructured arrays. The self-powered microstructured array air sampler was designed using computational fluid dynamics (CFD modeling to collect particles from 1-10 microns at greater than 99.9999 % efficiency with less than 100 Pascal [Pa] pressure drop at a specified air flow rate. Surprisingly, even at minimum air flow rates below specifications, these CFD predictions were matched by experimental results gathered in a Government aerosol chamber. The microstructured array engineered filter equaled the collection capability of a membrane or a high efficiency particle air (HEPA filter at a fraction of the filter pressure drop.

  16. Passive and Self-Powered Autonomous Sensors for Remote Measurements

    Directory of Open Access Journals (Sweden)

    Mauro Serpelloni

    2009-02-01

    Full Text Available Autonomous sensors play a very important role in the environmental, structural, and medical fields. The use of this kind of systems can be expanded for several applications, for example in implantable devices inside the human body where it is impossible to use wires. Furthermore, they enable measurements in harsh or hermetic environments, such as under extreme heat, cold, humidity or corrosive conditions. The use of batteries as a power supply for these devices represents one solution, but the size, and sometimes the cost and unwanted maintenance burdens of replacement are important drawbacks. In this paper passive and self-powered autonomous sensors for harsh or hermetical environments without batteries are discussed. Their general architectures are presented. Sensing strategies, communication techniques and power management are analyzed. Then, general building blocks of an autonomous sensor are presented and the design guidelines that such a system must follow are given. Furthermore, this paper reports different proposed applications of autonomous sensors applied in harsh or hermetic environments: two examples of passive autonomous sensors that use telemetric communication are proposed, the first one for humidity measurements and the second for high temperatures. Other examples of self-powered autonomous sensors that use a power harvesting system from electromagnetic fields are proposed for temperature measurements and for airflow speeds.

  17. Passive and self-powered autonomous sensors for remote measurements.

    Science.gov (United States)

    Sardini, Emilio; Serpelloni, Mauro

    2009-01-01

    Autonomous sensors play a very important role in the environmental, structural, and medical fields. The use of this kind of systems can be expanded for several applications, for example in implantable devices inside the human body where it is impossible to use wires. Furthermore, they enable measurements in harsh or hermetic environments, such as under extreme heat, cold, humidity or corrosive conditions. The use of batteries as a power supply for these devices represents one solution, but the size, and sometimes the cost and unwanted maintenance burdens of replacement are important drawbacks. In this paper passive and self-powered autonomous sensors for harsh or hermetical environments without batteries are discussed. Their general architectures are presented. Sensing strategies, communication techniques and power management are analyzed. Then, general building blocks of an autonomous sensor are presented and the design guidelines that such a system must follow are given. Furthermore, this paper reports different proposed applications of autonomous sensors applied in harsh or hermetic environments: two examples of passive autonomous sensors that use telemetric communication are proposed, the first one for humidity measurements and the second for high temperatures. Other examples of self-powered autonomous sensors that use a power harvesting system from electromagnetic fields are proposed for temperature measurements and for airflow speeds.

  18. Self-powered integrated systems-on-chip (energy chip)

    Science.gov (United States)

    Hussain, M. M.; Fahad, H.; Rojas, J.; Hasan, M.; Talukdar, A.; Oommen, J.; Mink, J.

    2010-04-01

    In today's world, consumer driven technology wants more portable electronic gadgets to be developed, and the next big thing in line is self-powered handheld devices. Therefore to reduce the power consumption as well as to supply sufficient power to run those devices, several critical technical challenges need to be overcome: a. Nanofabrication of macro/micro systems which incorporates the direct benefit of light weight (thus portability), low power consumption, faster response, higher sensitivity and batch production (low cost). b. Integration of advanced nano-materials to meet the performance/cost benefit trend. Nano-materials may offer new functionalities that were previously underutilized in the macro/micro dimension. c. Energy efficiency to reduce power consumption and to supply enough power to meet that low power demand. We present a pragmatic perspective on a self-powered integrated System on Chip (SoC). We envision the integrated device will have two objectives: low power consumption/dissipation and on-chip power generation for implementation into handheld or remote technologies for defense, space, harsh environments and medical applications. This paper provides insight on materials choices, intelligent circuit design, and CMOS compatible integration.

  19. Integrated self-powered microchip biosensor for endogenous biological cyanide.

    Science.gov (United States)

    Deng, Liu; Chen, Chaogui; Zhou, Ming; Guo, Shaojun; Wang, Erkang; Dong, Shaojun

    2010-05-15

    In this work we developed a fully integrated biofuel cell on a microchip, which consisted of glucose dehydrogenase supported (carbon nanotubes/thionine/gold nanoparticles)(8) multilayer as the anode, and the (carbon nanotubes/polylysine/laccase)(15) multilayer as the cathode. The as-obtained biofuel cell produced open circuit potential 620 mV and power density 302 microW cm(-2), showing great potential as a small power resource of portable electronics. Most importantly, for the first time we demonstrated the feasibility of developing a self-powered biosensor based on the inhibitive effect on microchip enzyme biofuel cell. With cyanide employed as the model analyte, this method showed a linear range of 3.0 x 10(-7) to 5.0 x 10(-4) M and a detection limit with 1.0 x 10(-7) M under the optimal conditions. The detection limit was lower than the acceptable cyanide concentration in drinking water (1.9 x 10(-6) M) according to the World Health Organization (WHO). This self-powered sensor was successfully used to detect the cyanide concentration in a real sample, cassava, which is the main carbohydrate resource in South America and Africa. This presented biosensor combined with a resistor and a multimeter demonstrated the general applicability as a fast and simple detection method in the determination of endogenous biological cyanide.

  20. A Wireless Self-Powered Urinary Incontinence Sensor System

    Science.gov (United States)

    Tanaka, Ami; Utsunomiya, Fumiyasu; Douseki, Takakuni

    A self-powered urinary incontinence sensor system consisting of a urine-activated coin battery and a wireless transmitter has been developed as an application for wireless biosensor networks. The urine-activated battery makes possible both the sensing of urine leakage and self-powered operation. An intermittent power-supply circuit that uses an electric double-layer capacitor (EDLC) with a small internal resistance suppresses the supply voltage drop due to the large internal resistance of the battery. This circuit and a 1-V surface acoustic wave (SAW) oscillator reduce the power dissipation of a wireless transmitter. The SAW oscillator quickly responds to the on-off control of the power supply, which is suitable for intermittent operation. To verify the effectiveness of the circuit scheme, the authors fabricated a prototype sensor system. When the volume of urine is 0.2 ml, the battery outputs a voltage of over 1.3 V; and the sensor system can transmit signals over a distance of 5 m.

  1. Large area self-powered gamma ray detector

    International Nuclear Information System (INIS)

    LeVert, F.E.

    1994-01-01

    The purpose of this research was to develop a large area self-powered gamma detector (LASPGD) capable of detecting the movement of sealed radiation sources into and out of industrial radiographic units and to construct a prototype source position monitor (SPM) for these units utilizing the LASPGD. Prototype isotropic and directional LASPGDs, with solid and inert gas dielectrics, were developed and extensively tested using calibrated gamma sources (i.e., Cs-137, and Co-60). The sensitivities of the isotropic detectors, with inert gas dielectrics, were found to be approximately a factor of ten greater than those measured for the solid dielectric LASPGDs. Directionally sensitive self-powered detectors were found to exhibit a forward-to-back hemispherical sensitivity ratio of approximately 2 to 1. Industrial radiographic units containing Ir-192 sources with different activities were used to test the performance of the SPM. The SPM, which utilized a gas dielectric LASPGD, performed as designed. That is, the current generated in the LASPGD was converted to a voltage, amplified and used to control the on/off state of an incandescent lamp. The incandescent lamp, which functions as the source/out warning indicator, flashes at a rate of one flash per second when the source is in use (i.e. out of its shield)

  2. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro.

    1995-01-01

    In a neutron flux monitoring device, there are disposed a neutron flux measuring means for outputting signals in accordance with the intensity of neutron fluxes, a calculation means for calculating a self power density spectrum at a frequency band suitable to an object to be measured based on the output of the neutron flux measuring means, an alarm set value generation means for outputting an alarm set value as a comparative reference, and an alarm judging means for comparing the alarm set value with the outputted value of the calculation means to judge requirement of generating an alarm and generate an alarm in accordance with the result of the judgement. Namely, the time-series of neutron flux signals is put to fourier transformation for a predetermined period of time by the calculation means, and from each of square sums for real number component and imaginary number component for each of the frequencies, a self power density spectrum in the frequency band suitable to the object to be measured is calculated. Then, when the set reference value is exceeded, an alarm is generated. This can reliably prevent generation of erroneous alarm due to neutron flux noises and can accurately generate an alarm at an appropriate time. (N.H.)

  3. Effect of cobalt-60 {gamma} radiation and of thermal neutrons on high resistance P and N silicon. Possibility of obtaining a nuclear compensation for P type silicon; Effects du rayonnement {gamma} du cobalt 60 et de neutrons thermiques sur du silicium P et N de haute resistivite. Possibilite de realiser une compensation nucleaire d'un silicium du type P

    Energy Technology Data Exchange (ETDEWEB)

    Messier, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-11-01

    Type P silicon has been compensated by the production of a controlled and uniform amount of donor atoms ({sup 31}P) using thermal neutrons to bring about a nuclear transformation. It is shown that it is possible in this way to reduce by a factor of about one hundred the overall concentration of residual ionised impurities in the purest crystals obtained by floating zone purification (2 x 10{sup 12} atoms/cm{sup 3}). The degree compensation obtained is limited by the initial inhomogeneity of acceptor impurities which have to be compensated. Lattice defects which still remain after prolonged annealings reduce the life-time of the material to about 10 {mu}s approximately. Particle detectors having thicknesses of 2 to 5 mm have been built by this process; they give good results, particularly at low temperatures. A study has also been made of the number and of the nature of lattice defects produced by thermal neutrons in high resistivity P and N type crystals. These defects have been compared to those produced by {gamma} rays from {sup 60}Co. A discussion is given of the validity of the Wertheim model concerning pronounced recombination at low temperatures (77 deg. K - 300 deg. K) of primary defect-interstitial pairs. The nature of the defects introducing energy levels into the lower half of the forbidden band has been studied. (author) [French] On a compense du silicium de type P en produisant, au moyen de neutrons thermiques, par transmutation nucleaire une quantite controlee et uniforme d'atomes donneurs ({sup 31}P). On montre qu'on peut ainsi reduire de cent fois environ la densite nette d'impuretes ionisees residuelles subsistant dans les cristaux les plus purs obtenus par purification par zone flottante (2.10{sup 12} atomes/cm{sup 3}). Le degre de compensation obtenu est limite par i'inhomogeneite initiale des impuretes acceptrices a compenser. Des defauts de reseau qui subsistent meme apres des recuits prolonges reduisent la duree de vie du materiau a 10 {mu

  4. Comparison study on in-core neutron detector for online neutron flux mapping of research and power reactor

    International Nuclear Information System (INIS)

    Zareen Khan Abdul Jalil Khan; Mohd Idris Taib; Izhar Abu Husin; Nurfarhana Ayuni

    2010-01-01

    This paper presents the comparison study on In-Core neutron detector using for online flux mapping of Research and Power reactor. Technical description of in-core neutron also taken into consideration to identify the different characterization of neutron detector and describe on Self Power neutron detector (SPND) for online neutron flux mapping. Able to provide information on the neutron flux distribution and understand how in-core neutron detector are being used in nuclear power plant including to enable to state the principles of neutron detector. (author)

  5. Passive (self-powered) fiber-optic sensors

    International Nuclear Information System (INIS)

    McElhaney, S.A.; Falter, D.D.; Todd, R.A.; Simpson, M.L.; Mihalczo, J.T.

    1992-01-01

    ORNL is developing new group of fiber-optic sensors for characterizing physical aspects such as ambient temperature. These sensors exploit the inherent property of thermographic materials that the lifetime and/or intensity of the emitted fluorescence decreases with increasing temperature. Unlike current fluorescent temperature sensors that use a light source for excitation, these sensors are totally passive (self-powered) and use either an embedded or external radiation source. A proof-of-principle temperature sensor was developed, based on this concept, using a well-known thermographic material, magnesium fluorogermanate. Experimental results showed that the radiation-induced fluorescence resulted in an intensity change but no significant decay rate change with increasing temperature

  6. Sulfur, cobalt and europium activation from the A-bombs in Japan

    International Nuclear Information System (INIS)

    Gritzner, M.L.; Egbert, S.D.; Woolson, W.A.

    1987-01-01

    Comparisons are made between calculations and measurements of in-situ sulfur, cobalt, and europium activation by neutrons at Hiroshima and Nagasaki to check the validity of the neutron sources and transport air-over-ground used in the new Dosimetry System 1986 (DS86). Europium and cobalt are activated by epithermal/thermal neutrons. The sulfur activation has an effective threshold around 2 MeV. Comparisons of sulfur activation at Hiroshima, which necessitate considering the tilt and heading of the cylindrically shaped Little Boy bomb, confirm the high energy neutron portion of the source relevant to sulfur activation. The europium and cobalt activation calculations tend to be higher than the measurements for ground ranges within 300 m and lower than the measurements beyond 700 m. Thus, the cobalt and europium measurements do not validate the source or the transport, embodied in DS87, for those neutrons relevant to europium and cobalt activation. Presently, it is unresolved as to whether the discrepancy can be explained as a problem in the measurements, in their interpretation, or as a problem in the calculations due to the source neutrons and/or their transport from source to the sample site

  7. Analysis of self-powered gamma ray detector with directional discrimination

    International Nuclear Information System (INIS)

    Levert, F.E.; Beyerlein, R.A.; Cox, S.A.

    1979-01-01

    The results of a combined Monte Carlo simulation and experimental investigation of the directional and energy dependent response of a self-powered gamma detector with a flat plate Pb-C central electrode are presented. The electron yield of the central electrode in a three dimensional mockup of the detector was calculated for photons of several discrete energies, emanating from an infinitely thin planar source, incident on the outer surface of the detector. Separate computations were done with the source facing the lead side and carbon side of the central electrode. Experimental measurements with a detector that closely matched the design used in the simulation were conducted in a graphite column next to a neutron leakage face of a low flux reactor. A localized gamma ray source was created by positioning a 235 U strip between the leakage face of the reactor and the detector. A comparison of results obtained in both cases showed good agreement. Also experimental measurements to determine the effect of the thickness of lead shielding surrounding the outer wall of the detector and space charge in the vacuum insulator between the central electrode and the inner wall on the response of the detector were performed. (Auth.)

  8. An analysis of cobalt irradiation in CANDU 6 reactor core

    International Nuclear Information System (INIS)

    Gugiu, E.D.; Dumitrache, I.

    2003-01-01

    In CANDU reactors, one has the ability to replace the stainless steel adjuster rods with neutronically equivalent Co assemblies with a minimum impact on the power plant safety and efficiency. The 60 Co produced by 59 Co irradiation is used extensively in medicine and industry. The paper mainly describes some of the reactor physics and safety requirements that must be carried into practice for the Co adjuster rods. The computations related to the neutronically equivalence of the stainless steel adjusters with the Co adjuster assemblies, as well as the estimations of the activity and the heating of the irradiated cobalt rods are performed using the Monte Carlo codes MCNP5 and MONTEBURNS2.1. The 60 Co activity and heating evaluations are closely related to the neutronics computations and to the density evolution of cobalt isotopes during assumed in-core irradiation period. Unfortunately, the activities of these isotopes could not be evaluated directly using the burn-up capabilities of the MONTEBURNS code because of the lack of their neutron cross-section from the MCNP5 code library. Additional MCNP5 runs for all the cobalt assemblies have been done in order to compute the flux-spectrum, the 59 Co and the 60 Co radiative capture reaction rates in the adjusters. The 60m Co cross-section was estimated using the flux-spectrum and the ORIGEN2.1 code capabilities THERM and RES. These computational steps allowed the evaluation of the one-group cross-section for the radiative capture reactions of cobalt isotopes. The values obtained replaced the corresponding ones from the ORIGEN library, which have been estimated using the flux-spectrum specific to the fuel. The activity values are used to evaluate the dose at the surface of the device designed to transport the cobalt adjusters. (authors)

  9. cobalt (ii), nickel (ii)

    African Journals Online (AJOL)

    DR. AMINU

    Department of Chemistry Bayero University, P. M. B. 3011, Kano, Nigeria. E-mail: hnuhu2000@yahoo.com. ABSTRACT. The manganese (II), cobalt (II), nickel (II) and .... water and common organic solvents, but are readily soluble in acetone. The molar conductance measurement [Table 3] of the complex compounds in.

  10. Convective flow reversal in self-powered enzyme micropumps.

    Science.gov (United States)

    Ortiz-Rivera, Isamar; Shum, Henry; Agrawal, Arjun; Sen, Ayusman; Balazs, Anna C

    2016-03-08

    Surface-bound enzymes can act as pumps that drive large-scale fluid flows in the presence of their substrates or promoters. Thus, enzymatic catalysis can be harnessed for “on demand” pumping in nano- and microfluidic devices powered by an intrinsic energy source. The mechanisms controlling the pumping have not, however, been completely elucidated. Herein, we combine theory and experiments to demonstrate a previously unreported spatiotemporal variation in pumping behavior in urease-based pumps and uncover the mechanisms behind these dynamics. We developed a theoretical model for the transduction of chemical energy into mechanical fluid flow in these systems, capturing buoyancy effects due to the solution containing nonuniform concentrations of substrate and product. We find that the qualitative features of the flow depend on the ratios of diffusivities δ=D(P)/D(S) and expansion coefficients β=β(P)/β(S) of the reaction substrate (S) and product (P). If δ>1 and δ>β (or if δself-powered fluidic devices.

  11. Energy harvesting for self-powered aerostructure actuation

    Science.gov (United States)

    Bryant, Matthew; Pizzonia, Matthew; Mehallow, Michael; Garcia, Ephrahim

    2014-04-01

    This paper proposes and experimentally investigates applying piezoelectric energy harvesting devices driven by flow induced vibrations to create self-powered actuation of aerostructure surfaces such as tabs, flaps, spoilers, or morphing devices. Recently, we have investigated flow-induced vibrations and limit cycle oscillations due to aeroelastic flutter phenomena in piezoelectric structures as a mechanism to harvest energy from an ambient fluid flow. We will describe how our experimental investigations in a wind tunnel have demonstrated that this harvested energy can be stored and used on-demand to actuate a control surface such as a trailing edge flap in the airflow. This actuated control surface could take the form of a separate and discrete actuated flap, or could constitute rotating or deflecting the oscillating energy harvester itself to produce a non-zero mean angle of attack. Such a rotation of the energy harvester and the associated change in aerodynamic force is shown to influence the operating wind speed range of the device, its limit cycle oscillation (LCO) amplitude, and its harvested power output; hence creating a coupling between the device's performance as an energy harvester and as a control surface. Finally, the induced changes in the lift, pitching moment, and drag acting on a wing model are quantified and compared for a control surface equipped with an oscillating energy harvester and a traditional, static control surface of the same geometry. The results show that when operated in small amplitude LCO the energy harvester adds negligible aerodynamic drag.

  12. Self powered platinum flux detector application for shutdown system

    International Nuclear Information System (INIS)

    Su Guoquan

    2005-01-01

    This article introduce Neutron Flux Detector application in Candu Power Plant, including: design purpose, location in the site, dynamic compensation, differential compensation, detector assembly pressurized with high pure helium etc. And shielding grounding improvement is suggested because of detector signal and setpoint signal noise. (authors)

  13. A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity

    KAUST Repository

    Leung, Siu; Ho, Kang-Ting; Kung, Po-Kai; Hsiao, Vincent K. S.; Alshareef, Husam N.; Wang, Zhong Lin; He, Jr-Hau

    2018-01-01

    Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH3 NH3 PBI3

  14. Absolute measurement of the critical scattering cross section in cobalt

    International Nuclear Information System (INIS)

    Glinka, C.J.; Minkiewicz, V.J.; Passell, L.

    1975-01-01

    Small-angle neutron scattering techniques have been used to study the angular distribution of the critical scattering from cobalt above T/sub c/. These measurements have been put on an absolute scale by calibrating the critical scattering directly against the nuclear incoherent scattering from cobalt. In this way the interaction range r 1 , which appears in the classical and modified Ornstein--Zernike expressions for the asymptotic form of the spin pair correlation function and is related to the strength of the spin correlations, has been determined. We obtain r 1 /a = 0.46 +- 0.03 for the ratio of the interaction range to the nearest-neighbor distance in cobalt. This result is in good agreement with theoretical predictions. Lack of agreement among previous determinations of the ratio r 1 /a made in iron failed to provide a definitive comparison with theory

  15. New avenues in cobalt-60 production at Ontario Hydro

    International Nuclear Information System (INIS)

    Mylvaganam, C.K.; Ronchka, R.A.

    1990-01-01

    Ontario Hydro produces cobalt-60 in the control rods of twelve power reactors. These reactors have a typical flux of 2 x 10 14 neutrons/cm 2 /s, making them efficient producers of cobalt-60. Current annual production is 45 million curies. Since the primary function of these reactors is the production of electricity, their flexibility to meet the needs of commercial cobalt production by the control rod route is limited. Ontario Hydro is therefore developing innovative production techniques, making use of the CANDU reactor's unique ability to be fuelled on-power. These techniques will enable production to better respond to the market's requirements for quantity and specific activity. As it is supplementary to control rod production, annual supply could potentially reach 165 million curies. (author)

  16. Heating analysis of cobalt adjusters in reactor core

    International Nuclear Information System (INIS)

    Mei Qiliang; Li Kang; Fu Yaru

    2011-01-01

    In order to produce 60 Co source for industry and medicine applications in CANDU-6 reactor, the stainless steel adjusters were replaced with the cobalt adjusters. The cobalt rod will generate the heat when it is irradiated by neutron and γ ray. In addition, 59 Co will be activated and become 60 Co, the ray released due to 60 Co decay will be absorbed by adjusters, and then the adjusters will also generate the heat. So the heating rate of adjusters to be changed during normal operation must be studied, which will be provided as the input data for analyzing the temperature field of cobalt adjusters and the relative heat load of moderator. MCNP code was used to simulate whole core geometric configuration in detail, including reactor fuel, control rod, adjuster, coolant and moderator, and to analyze the heating rate of the stainless steel adjusters and the cobalt adjusters. The maximum heating rate of different cobalt adjuster based on above results will be provided for the steady thermal hydraulic and accident analysis, and make sure that the reactor is safe on the thermal hydraulic. (authors)

  17. Analysis of radioactive cobalt

    International Nuclear Information System (INIS)

    1977-01-01

    This is a manual published by Science and Technology Agency, Japan, which prescribes on the analysis method for radioactive cobalt which is a typical indexing nuclide among the radioactive nuclides released from nuclear facilities. Since the released cobalt is mainly discharged to coastal region together with waste water, this manual is written for samples of sea water, sea bottom sediments and marine organisms. Radioactive cobalt includes the nuclides of 57 co, 58 Co, 60 Co, etc., the manual deals with them as a whole as 60 Co of long half life. Though 60 Co analysis has become feasible comparatively simply due to scintillation or semi-conductor spectrometry, trace 60 Co analysis is performed quantitatively by co-precipitation or collection into alumina and scintillation spectrometry. However, specific collecting operation and γ-γ coincidence measurement have been required so far. This manual employs 60 Co collection by means of ion-exchange method and measurement with low background GM counting system, to analyze quantitatively and rapidly low level 60 Co. It is primarily established as the standard analyzing method for the survey by local autonomous bodies. It is divided into 4 chapters including introduction sea water, marine organisms, and sea bottom sediments. List of required reagents is added in appendix. (Wakatsuki, Y.)

  18. Self-powered suspension criterion and energy regeneration implementation scheme of motor-driven active suspension

    Science.gov (United States)

    Yan, Shuai; Sun, Weichao

    2017-09-01

    Active suspension systems have advantages on mitigating the effects of vehicle vibration caused by road roughness, which are one of the most important component parts in influencing the performances of vehicles. However, high amount of energy consumption restricts the application of active suspension systems. From the point of energy saving, this paper presents a self-powered criterion of the active suspension system to judge whether a motor-driven suspension can be self-powered or not, and then a motor parameter condition is developed as a reference to design a self-powered suspension. An energy regeneration implementation scheme is subsequently proposed to make the active suspension which has the potential to be self-powered achieve energy-saving target in the real application. In this implementation scheme, operating electric circuits are designed based on different working status of the actuator and power source and it is realizable to accumulate energy from road vibration and supply energy to the actuator by switching corresponding electric circuits. To apply the self-powered suspension criterion and energy regeneration implementation scheme, an active suspension system is designed with a constrained H∞ controller and calculation results indicate that it has the capability to be self-powered. Simulation results show that the performances of the self-powered active suspension are nearly the same as those of the active suspension with an external energy source and can achieve energy regeneration at the same time.

  19. Towards Flexible Self-powered Micro-scale Integrated Systems

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-04-01

    nanotubes (CNT)-based anode and the second with a more sustainable design and easy to implement. Power production ranges from 392 to 100 mW/m3 depending on design. Additionally we have explored a flexible thermoelectric generator (0.139 μW/cm2) and a lithium-ion battery (~800 μAh/m2) for back-up energy generation and storage. Future work includes the implementation of a self-powered System-on-Package which gathers together energy generation, storage and consumption. Additionally we are working to demonstrate Complementary Metal-Oxide-Semiconductor (CMOS) circuitry on our flexible platform, as well as memory systems.

  20. Blood doping by cobalt. Should we measure cobalt in athletes?

    Directory of Open Access Journals (Sweden)

    Guidi Gian

    2006-07-01

    Full Text Available Abstract Background Blood doping is commonplace in competitive athletes who seek to enhance their aerobic performances through illicit techniques. Presentation of the hypothesis Cobalt, a naturally-occurring element with properties similar to those of iron and nickel, induces a marked and stable polycythemic response through a more efficient transcription of the erythropoietin gene. Testing the hypothesis Although little information is available so far on cobalt metabolism, reference value ranges or supplementation in athletes, there is emerging evidence that cobalt is used as a supplement and increased serum concentrations are occasionally observed in athletes. Therefore, given the athlete's connatural inclination to experiment with innovative, unfair and potentially unhealthy doping techniques, cobalt administration might soon become the most suited complement or surrogate for erythropoiesis-stimulating substances. Nevertheless, cobalt administration is not free from unsafe consequences, which involve toxic effects on heart, liver, kidney, thyroid and cancer promotion. Implications of the hypothesis Cobalt is easily purchasable, inexpensive and not currently comprehended within the World Anti-Doping Agency prohibited list. Moreover, available techniques for measuring whole blood, serum, plasma or urinary cobalt involve analytic approaches which are currently not practical for antidoping laboratories. Thus more research on cobalt metabolism in athletes is compelling, along with implementation of effective strategies to unmask this potentially deleterious doping practice

  1. Notes on neutron flux measurement

    International Nuclear Information System (INIS)

    Alcala Ruiz, F.

    1984-01-01

    The main purpose of this work is to get an useful guide to carry out topical neutron flux measurements. Although the foil activation technique is used in the majority of the cases, other techniques, such as those based on fission chambers and self-powered neutron detectors, are also shown. Special interest is given to the description and application of corrections on the measurement of relative and absolute induced activities by several types of detectors (scintillators, G-M and gas proportional counters). The thermal arid epithermal neutron fluxes, as determined in this work, are conventional or effective (West cots fluxes), which are extensively used by the reactor experimentalists; however, we also give some expressions where they are related to the integrated neutron fluxes, which are used in neutron calculations. (Author) 16 refs

  2. Nickel, cobalt, and their alloys

    CERN Document Server

    2000-01-01

    This book is a comprehensive guide to the compositions, properties, processing, performance, and applications of nickel, cobalt, and their alloys. It includes all of the essential information contained in the ASM Handbook series, as well as new or updated coverage in many areas in the nickel, cobalt, and related industries.

  3. Innovative Self-Powered and Self-Contained Sensor Array for Separation Detection, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a self-contained, self-powered, robust flight test sensor array for the determination of separation. The proposed system uses off the...

  4. Cobalt source calibration

    International Nuclear Information System (INIS)

    Rizvi, H.M.

    1999-01-01

    The data obtained from these tests determine the dose rate of the two cobalt sources in SRTC. Building 774-A houses one of these sources while the other resides in room C-067 of Building 773-A. The data from this experiment shows the following: (1) The dose rate of the No.2 cobalt source in Building 774-A measured 1.073 x 10 5 rad/h (June 17, 1999). The dose rate of the Shepherd Model 109 Gamma cobalt source in Building 773-A measured 9.27 x 10 5 rad/h (June 25, 1999). These rates come from placing the graduated cylinder containing the dosimeter solution in the center of the irradiation chamber. (2) Two calibration tests in the 774-A source placed the graduated cylinder with the dosimeter solution approximately 1.5 inches off center in the axial direction. This movement of the sample reduced the measured dose rate 0.92% from 1.083 x 10 5 rad/h to 1.073 x 10 5 rad/h. and (3) A similar test in the cobalt source in 773-A placed the graduated cylinder approximately 2.0 inches off center in the axial direction. This change in position reduced the measured dose rate by 10.34% from 1.036 x 10 6 to 9.27 x 10 5 . This testing used chemical dosimetry to measure the dose rate of a radioactive source. In this method, one determines the dose by the chemical change that takes place in the dosimeter. For this calibration experiment, the author used a Fricke (ferrous ammonium sulfate) dosimeter. This solution works well for dose rates to 10 7 rad/h. During irradiation of the Fricke dosimeter solution the Fe 2+ ions ionize to Fe 3+ . When this occurs, the solution acquires a slightly darker tint (not visible to the human eye). To determine the magnitude of the change in Fe ions, one places the solution in an UV-VIS Spectrophotometer. The UV-VIS Spectrophotometer measures the absorbency of the solution. Dividing the absorbency by the total time (in minutes) of exposure yields the dose rate

  5. Unithiol - a cobalt antidote

    International Nuclear Information System (INIS)

    Cherkes, A.I.; Braver-Chernobul'skaya, B.S.

    1977-06-01

    The blockade of the sulfhydryl groups of the proteins leads to a disturbance of the normal activity of many enzymes and thus of the functioning of the organs and tissue. The search for antidotes against these substances which inactivate the enzymes led to the synthesis of a large group of thiols in the Ukrainian Scientific Research Sanitary Chemical Institute. The most active is sodium dithiol-2,3-dimercaptonpropansulphonate CH 2 SH-CHSH-CH 2 SO 3 Na x H 2 O, named unithiol. Its antidote activity is discussed in detail, especially concerning cobalt intoxication. (HK) [de

  6. A method for prompt calculation of neutron flux from measured SPND [self-powered neutron detectors] currents

    International Nuclear Information System (INIS)

    Kulacsy, K.; Lux, I.

    1997-01-01

    A new, approximate method is given to calculate the in-core flux from the current of SPNDs, with a delay of only a few seconds. The stability of this stepwise algorithm is proven to be satisfactory, and the results of tests performed both on synthetic and on real data are presented. The reconstructed flux is found to follow both steady state and transient fluxes well. (author)

  7. Radio cobalt in French rivers

    International Nuclear Information System (INIS)

    Lambrechts, A.; Baudin-Jaulent, Y.

    1996-01-01

    The isotopes 58 and 60 of cobalt present in liquid wastes from nuclear plants or from fuel reprocessing plant of Marcoule are fixed in the different compartments of French rivers. The activity levels of radio-cobalt vary according to the sampled compartments nature (bryophyta > immersed plants > sediment > fish). Elsewhere, laboratory experimentations show that the contamination of fish occurs essentially from the water way rather than from food. Cobalt is mainly fixed by kidneys; muscles is no more than 30 % of the total fish activity. (author)

  8. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  9. A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity

    KAUST Repository

    Leung, Siu

    2018-01-10

    Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH3 NH3 PBI3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH3 NH3 PBI3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 1013 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW-1 cm-2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications.

  10. A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector with Very High Detectivity.

    Science.gov (United States)

    Leung, Siu-Fung; Ho, Kang-Ting; Kung, Po-Kai; Hsiao, Vincent K S; Alshareef, Husam N; Wang, Zhong Lin; He, Jr-Hau

    2018-02-01

    Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH 3 NH 3 PBI 3 ) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH 3 NH 3 PBI 3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 10 13 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW -1 cm -2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. A novel self-powered wireless temperature sensor based on thermoelectric generators

    International Nuclear Information System (INIS)

    Shi, Yongming; Wang, Yao; Deng, Yuan; Gao, Hongli; Lin, Zhen; Zhu, Wei; Ye, Huihong

    2014-01-01

    Highlights: • A self-powered temperature sensor, based on thermoelectric generator, is presented. • This novel sensor can operate without any batteries or other power sources. • This sensor combines signal sensing and power supplying together. • The measurement error is 0.5 K during the sensor operating period. • This sensor can detect temperature fluctuation situations such as fire disaster. - Abstract: A novel self-powered wireless temperature sensor has been designed and presented for solving the power supply problem of temperature sensors. This sensor can autonomously measure temperature under positive temperature fluctuation situations. The self-powered characteristic, realized by using four thermoelectric generators, enables the sensor to operate without any batteries or other power sources. In order to obtain these features, attentions are not only focused on the method to combine signal sensing and power generating together, but also on the method to improve measurement accuracy. Experimental results confirm that this novel sensor has excellent measurement accuracy. The measured performance is consistent with the calculated characteristics. For typical application, this self-powered temperature sensor can detect fire before it develops to flashover state. And the maximum detection distance grows with the growth of burning rate. All the results indicate this innovative sensor is a promising self-powered device which can be used to measure temperature value in positive temperature fluctuation situations

  12. Cobalt: for strength and color

    Science.gov (United States)

    Boland, Maeve A.; Kropschot, S.J.

    2011-01-01

    Cobalt is a shiny, gray, brittle metal that is best known for creating an intense blue color in glass and paints. It is frequently used in the manufacture of rechargeable batteries and to create alloys that maintain their strength at high temperatures. It is also one of the essential trace elements (or "micronutrients") that humans and many other living creatures require for good health. Cobalt is an important component in many aerospace, defense, and medical applications and is a key element in many clean energy technologies. The name cobalt comes from the German word kobold, meaning goblin. It was given this name by medieval miners who believed that troublesome goblins replaced the valuable metals in their ore with a substance that emitted poisonous fumes when smelted. The Swedish chemist Georg Brandt isolated metallic cobalt-the first new metal to be discovered since ancient times-in about 1735 and identified some of its valuable properties.

  13. Cobalt release from implants and consumer items and characteristics of cobalt sensitized patients with dermatitis

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Menne, Torkil; Liden, Carola

    2012-01-01

    -containing dental alloys and revised hip implant components.Results. Six of eight dental alloys and 10 of 98 revised hip implant components released cobalt in the cobalt spot test, whereas none of 50 mobile phones gave positive reactions. The clinical relevance of positive cobalt test reactions was difficult......-tested dermatitis patients in an attempt to better understand cobalt allergy.Materials and methods. 19 780 dermatitis patients aged 4-99 years were patch tested with nickel, chromium or cobalt between 1985 and 2010. The cobalt spot test was used to test for cobalt ion release from mobile phones as well as cobalt...

  14. Electroplated zinc-cobalt alloy

    International Nuclear Information System (INIS)

    Carpenter, D.E.O.S.; Farr, J.P.G.

    2005-01-01

    Recent work on the deposition and use of ectrodeposited zinc-cobalt alloys is surveyed. Alloys containing lower of Nuclear quantities of cobalt are potentially more useful. The structures of the deposits is related to their chemical and mechanical properties. The inclusion of oxide and its role in the deposition mechanism may be significant. Chemical and engineering properties relate to the metallurgical structure of the alloys, which derives from the mechanism of deposition. The inclusion of oxides and hydroxides in the electroplate may provide evidence for this mechanism. Electrochemical impedance measurements have been made at significant deposition potentials, in alkaline electrolytes. These reveal a complex electrode behaviour which depends not only on the electrode potential but on the Co content of the electrolyte. For the relevant range of cathodic potential zinc-cobalt alloy electrodeposition occurs through a stratified interface. The formation of an absorbed layer ZnOH/sup +/ is the initial step, this inhibits the deposition of cobalt at low cathodic potentials, so explaining its 'anomalous deposition'. A porous layer of zinc forms on the adsorbed ZnOH/sup +/ at underpotential. As the potential becomes more cathodic, cobalt co- deposits from its electrolytic complex forming a metallic solid solution of Co in Zn. In electrolytes containing a high concentration of cobalt a mixed entity (ZnCo)/sub +/ is assumed to adsorb at the cathode from which a CoZn intermetallic deposits. (author)

  15. Wearable and Implantable Mechanical Energy Harvesters for Self-Powered Biomedical Systems.

    Science.gov (United States)

    Hinchet, Ronan; Kim, Sang-Woo

    2015-08-25

    In this issue of ACS Nano, Tang et al. investigate the ability of a triboelectric nanogenerator (TENG) to self-power a low-level laser cure system for osteogenesis by studying the efficiency of a bone remodeling laser treatment that is powered by a skin-patch-like TENG instead of a battery. We outline this field by highlighting the motivations for self-powered biomedical systems and by discussing recent progress in nanogenerators. We note the overlap between biomedical devices and TENGs and their dawning synergy, and we highlight key prospects for future developments. Biomedical systems should be more autonomous. This advance could improve their body integration and fields of action, leading to new medical diagnostics and treatments. However, future self-powered biomedical systems will need to be more flexible, biocompatible, and biodegradable. These advances hold the promise of enabling new smart autonomous biomedical systems and contributing significantly to the Internet of Things.

  16. COBALT SALTS PRODUCTION BY USING SOLVENT EXTRACTION

    Directory of Open Access Journals (Sweden)

    Liudmila V. Dyakova

    2010-06-01

    Full Text Available The paper deals with the extracting cobalt salts by using mixtures on the basis of tertiary amine from multicomponent solutions from the process of hydrochloride leaching of cobalt concentrate. The optimal composition for the extraction mixture, the relationship between the cobalt distribution coefficients and modifier’s nature and concentration, and the saltingout agent type have been determined. A hydrochloride extraction technology of cobalt concentrate yielding a purified concentrated cobalt solution for the production of pure cobalt salts has been developed and introduced at Severonikel combine.

  17. A CMOS self-powered front-end architecture for subcutaneous event-detector devices

    CERN Document Server

    Colomer-Farrarons, Jordi

    2011-01-01

    A CMOS Self-Powered Front-End Architecture for Subcutaneous Event-Detector Devices presents the conception and prototype realization of a Self-Powered architecture for subcutaneous detector devices. The architecture is designed to work as a true/false (event detector) or threshold level alarm of some substances, ions, etc. that are detected through a three-electrodes amperometric BioSensor approach. The device is conceived as a Low-Power subcutaneous implantable application powered by an inductive link, one emitter antenna at the external side of the skin and the receiver antenna under the ski

  18. Field emission device driven by self-powered contact-electrification: Simulation and experimental analysis

    Science.gov (United States)

    Chen, Xiangyu; Jiang, Tao; Sun, Zhuo; Ou-Yang, Wei

    2015-09-01

    A self-powered field emission device (FED) driven by a single-electrode tribo-electric nanogenerator (TENG) is demonstrated. The mechanical motion works as both a power supply to drive the FED and a control unit to regulate the amount of emitted electrons. By using the Fowler-Nordheim equation and Kirchhoff laws, a theoretical model of this self-powered FED is proposed, and accordingly the real-time output characteristics of the device are systematically investigated. It is found that the motion distance of the TENG controls switch-on of the FED and determines the charge amount for emission, while the motion velocity regulates the amplitude of emission current. The minimum contact area for the TENG to generate field emission is about 9 cm2, which can be improved by optimizing FED structure and the tribo-materials of TENG. The demonstrated concept of this self-powered FED as well as the proposed physical analysis can serve as guidance for further applications of FED in such fields of self-powered electronics and soft electronics.

  19. Field emission device driven by self-powered contact-electrification: Simulation and experimental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiangyu, E-mail: chenxiangyu@binn.cas.cn, E-mail: ouyangwei@phy.ecnu.edu.cn; Jiang, Tao [Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083 (China); Sun, Zhuo; Ou-Yang, Wei, E-mail: chenxiangyu@binn.cas.cn, E-mail: ouyangwei@phy.ecnu.edu.cn [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China)

    2015-09-14

    A self-powered field emission device (FED) driven by a single-electrode tribo-electric nanogenerator (TENG) is demonstrated. The mechanical motion works as both a power supply to drive the FED and a control unit to regulate the amount of emitted electrons. By using the Fowler-Nordheim equation and Kirchhoff laws, a theoretical model of this self-powered FED is proposed, and accordingly the real-time output characteristics of the device are systematically investigated. It is found that the motion distance of the TENG controls switch-on of the FED and determines the charge amount for emission, while the motion velocity regulates the amplitude of emission current. The minimum contact area for the TENG to generate field emission is about 9 cm{sup 2}, which can be improved by optimizing FED structure and the tribo-materials of TENG. The demonstrated concept of this self-powered FED as well as the proposed physical analysis can serve as guidance for further applications of FED in such fields of self-powered electronics and soft electronics.

  20. Analysis of output currents of self-powered detectors polarized by an external potential

    Energy Technology Data Exchange (ETDEWEB)

    Pytel, K; Glowacki, S

    1980-01-01

    During measurement of self-powered detector current the electrical potential is induced between the emitter and collector caused by the input resistivity of measuring device. The detector current dependence on the emitter potential has been analyzed. The experimental results confirm the theoretical model of electronic processes within the insulator and also give the requirements that measuring device should fulfil.

  1. Self-Powered Functional Device Using On-Chip Power Generation

    KAUST Repository

    Hussain, Muhammad Mustafa

    2012-01-26

    An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

  2. Advanced Nanofabrication Process Development for Self-Powered System-on-Chip

    KAUST Repository

    Rojas, Jhonathan Prieto

    2010-01-01

    In summary, by using a novel sustainable energy component and scalable nano-patterning for logic and computing module, this work has successfully collected the essential base knowledge and joined two different elements that synergistically will contribute for the future implementation of a Self-Powered System-on-Chip.

  3. A novel high-performance self-powered ultraviolet photodetector: Concept, analytical modeling and analysis

    Science.gov (United States)

    Ferhati, H.; Djeffal, F.

    2017-12-01

    In this paper, a new MSM-UV-photodetector (PD) based on dual wide band-gap material (DM) engineering aspect is proposed to achieve high-performance self-powered device. Comprehensive analytical models for the proposed sensor photocurrent and the device properties are developed incorporating the impact of DM aspect on the device photoelectrical behavior. The obtained results are validated with the numerical data using commercial TCAD software. Our investigation demonstrates that the adopted design amendment modulates the electric field in the device, which provides the possibility to drive appropriate photo-generated carriers without an external applied voltage. This phenomenon suggests achieving the dual role of effective carriers' separation and an efficient reduce of the dark current. Moreover, a new hybrid approach based on analytical modeling and Particle Swarm Optimization (PSO) is proposed to achieve improved photoelectric behavior at zero bias that can ensure favorable self-powered MSM-based UV-PD. It is found that the proposed design methodology has succeeded in identifying the optimized design that offers a self-powered device with high-responsivity (98 mA/W) and superior ION/IOFF ratio (480 dB). These results make the optimized MSM-UV-DM-PD suitable for providing low cost self-powered devices for high-performance optical communication and monitoring applications.

  4. Self-Powered Functional Device Using On-Chip Power Generation

    KAUST Repository

    Hussain, Muhammad Mustafa

    2012-01-01

    An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

  5. Solar driven electrochromic photoelectrochemical fuel cells for simultaneous energy conversion, storage and self-powered sensing.

    Science.gov (United States)

    Wang, Yanhu; Zhang, Lina; Cui, Kang; Xu, Caixia; Li, Hao; Liu, Hong; Yu, Jinghua

    2018-02-15

    One solar-driven electrochromic photoelectrochemical fuel cell (PFC) with highly efficient energy conversion and storage is easily constructed to achieve quantitative self-powered sensing. Layered bismuth oxyiodide-zinc oxide nanorod arrays (ZnO@BiOI NRA) with a core/shell p-n heterostructure are fabricated as the photoanode with electrochromic Prussian blue (PB) as the cathode. The core/shell p-n heterostructure for the ZnO@BiOI photoanode can effectively boost the photoelectrochemical (PEC) performance through the improvement of photon absorption and charge carrier separation. The optimal assembled PFC yields an open-circuit voltage (V OC ) of 0.48 V with the maximum power output density (P max ) as high as 155 μW cm -2 upon illumination. Benefitting from the interactive color-changing behavior of PB, the cathode not only exhibits cathodic catalytic activity in the PFC but also serves as an electrochromic display for self-powered sensing. The as-constructed PFC possesses multiple readable signal output nanochannels through the maximum power output density (P max ) of the PFC or the color change of PB. Meanwhile, the dual-signal-output makes the as-constructed self-powered sensor highly available in various operations demands with the enhanced reliability. With the advantages of high efficiency of PFCs, unique assay ability, and broad environmental suitability, the constructed self-powered platform shows broad application prospects as an integrated smart analytical device.

  6. Field emission device driven by self-powered contact-electrification: Simulation and experimental analysis

    International Nuclear Information System (INIS)

    Chen, Xiangyu; Jiang, Tao; Sun, Zhuo; Ou-Yang, Wei

    2015-01-01

    A self-powered field emission device (FED) driven by a single-electrode tribo-electric nanogenerator (TENG) is demonstrated. The mechanical motion works as both a power supply to drive the FED and a control unit to regulate the amount of emitted electrons. By using the Fowler-Nordheim equation and Kirchhoff laws, a theoretical model of this self-powered FED is proposed, and accordingly the real-time output characteristics of the device are systematically investigated. It is found that the motion distance of the TENG controls switch-on of the FED and determines the charge amount for emission, while the motion velocity regulates the amplitude of emission current. The minimum contact area for the TENG to generate field emission is about 9 cm 2 , which can be improved by optimizing FED structure and the tribo-materials of TENG. The demonstrated concept of this self-powered FED as well as the proposed physical analysis can serve as guidance for further applications of FED in such fields of self-powered electronics and soft electronics

  7. Recent Progress of Self-Powered Sensing Systems for Wearable Electronics.

    Science.gov (United States)

    Lou, Zheng; Li, La; Wang, Lili; Shen, Guozhen

    2017-12-01

    Wearable/flexible electronic sensing systems are considered to be one of the key technologies in the next generation of smart personal electronics. To realize personal portable devices with mobile electronics application, i.e., wearable electronic sensors that can work sustainably and continuously without an external power supply are highly desired. The recent progress and advantages of wearable self-powered electronic sensing systems for mobile or personal attachable health monitoring applications are presented. An overview of various types of wearable electronic sensors, including flexible tactile sensors, wearable image sensor array, biological and chemical sensor, temperature sensors, and multifunctional integrated sensing systems is provided. Self-powered sensing systems with integrated energy units are then discussed, separated as energy harvesting self-powered sensing systems, energy storage integrated sensing systems, and all-in-on integrated sensing systems. Finally, the future perspectives of self-powered sensing systems for wearable electronics are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Phosphorus introduction mechanism in electrodeposited cobalt films

    International Nuclear Information System (INIS)

    Kravtchenko, Jean-Francois

    1973-01-01

    The cathodic reduction of hypophosphite, phosphite and phosphate ions was studied using chrono-potentiometry and voltammetry. Then cobalt was deposited at constant current from a bath containing one of these three compounds. The current, while giving an electrodeposition of cobalt, also enhances at the same time a chemical deposition of cobalt. It is shown that high coercive forces in cobalt films are much more related to this chemical deposition than to the simple fact that the films contain some phosphorus. (author) [fr

  9. National Low-Level Waste Management Program Radionuclide Report Series: Volume 12, Cobalt-60

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.P.

    1995-06-01

    This report outlines the basic radiological and chemical characteristics of cobalt-60 ({sup 60}Co) and examines how these characteristics affect the behavior of {sup 60}Co in various environmental media, such as soils, groundwater, plants, animals, the atmosphere, and the human body. Discussions also include methods of {sup 60}Co production, waste types, and waste forms that contain {sup 60}Co. All cobalt atoms contain 27 protons (Z = 27) and various numbers of neutrons (typically N = 27 to 37 neutrons) within the atom`s nucleus. There is only one stable isotope of cobalt, namely {sup 59}Co. All other cobalt isotopes, including {sup 60}Co, are radioactive. The radioactive isotopes of cobalt have half-lives ranging from less than a second ({sup 54}Co-0.19 s) to 5.2 years ({sup 60}Co). The radioactive isotopes of cobalt are not a normal constituent of the natural environment and are generated as a result of human activities. The primary source of {sup 60}Co in the environment has been low-level radioactive waste material generated as a result of neutron activation of stable {sup 59}Co that is present in the structural components of nuclear reactor vessels. This isotope is also intentionally produced, usually in reactors but also to some degree in accelerators for industrial and medical uses, such as for radiation sources for cancer treatment and nondestructive testing of metals and welds. {sup 60}Co may enter the environment as a result of the activities associated with nuclear reactor operations and decommissioning and when industrial and medical sources are being used, manufactured, or disposed.

  10. National Low-Level Waste Management Program Radionuclide Report Series: Volume 12, Cobalt-60

    International Nuclear Information System (INIS)

    Adams, J.P.

    1995-06-01

    This report outlines the basic radiological and chemical characteristics of cobalt-60 ( 60 Co) and examines how these characteristics affect the behavior of 60 Co in various environmental media, such as soils, groundwater, plants, animals, the atmosphere, and the human body. Discussions also include methods of 60 Co production, waste types, and waste forms that contain 60 Co. All cobalt atoms contain 27 protons (Z = 27) and various numbers of neutrons (typically N = 27 to 37 neutrons) within the atom's nucleus. There is only one stable isotope of cobalt, namely 59 Co. All other cobalt isotopes, including 60 Co, are radioactive. The radioactive isotopes of cobalt have half-lives ranging from less than a second ( 54 Co-0.19 s) to 5.2 years ( 60 Co). The radioactive isotopes of cobalt are not a normal constituent of the natural environment and are generated as a result of human activities. The primary source of 60 Co in the environment has been low-level radioactive waste material generated as a result of neutron activation of stable 59 Co that is present in the structural components of nuclear reactor vessels. This isotope is also intentionally produced, usually in reactors but also to some degree in accelerators for industrial and medical uses, such as for radiation sources for cancer treatment and nondestructive testing of metals and welds. 60 Co may enter the environment as a result of the activities associated with nuclear reactor operations and decommissioning and when industrial and medical sources are being used, manufactured, or disposed

  11. Molecular mechanics calculations on cobalt phthalocyanine dimers

    NARCIS (Netherlands)

    Heuts, J.P.A.; Schipper, E.T.W.M.; Piet, P.; German, A.L.

    1995-01-01

    In order to obtain insight into the structure of cobalt phthalocyanine dimers, molecular mechanics calculations were performed on dimeric cobalt phthalocyanine species. Molecular mechanics calculations are first presented on monomeric cobalt(II) phthalocyanine. Using the Tripos force field for the

  12. Transport of cobalt-60 industrial radiation sources

    Science.gov (United States)

    Kunstadt, Peter; Gibson, Wayne

    This paper will deal with safety aspects of the handling of Cobalt-60, the most widely used industrial radio-isotope. Cobalt-60 is a man-made radioisotope of Cobalt-59, a naturally occurring non radioactive element, that is made to order for radiation therapy and a wide range of industrial processing applications including sterilization of medical disposables, food irradiation, etc.

  13. Accumulation of cobalt by cephalopods

    International Nuclear Information System (INIS)

    Nakahara, Motokazu

    1981-01-01

    Accumulation of cobalt by cephalopod mollusca was investigated by radiotracer experiments and elemental analysis. In the radiotracer experiments, Octopus vulgaris took up cobalt-60 from seawater fairly well and the concentration of the nuclide in whole body attained about 150 times the level of seawater at 25th day at 20 0 C. Among the tissues and organs measured, branchial heart which is the specific organ of cephalopods showed the highest affinity for the nuclide. The organ accumulated about 50% of the radioactivity in whole body in spite of its little mass as 0.2% of total body weight. On the other hand, more than 90% of the radioactivity taken up from food (soft parts of Gomphina melanaegis labelled with cobalt-60 previously in an aquarium) was accumulated in liver at 3rd day after the single administration and then the radioactivity in the liver seemed to be distributed to other organs and tissues. The characteristic elution profiles of cobalt-60 was observed for each of the organs and tissues in Sephadex gel-filtration experiment. It was confirmed by the gel-filtration that most of cobalt-60 in the branchial heart was combined with the constituents of low molecular weights. The average concentration of stable cobalt in muscle of several species of cephalopods was 5.3 +- 3.0 μg/kg wet and it was almost comparable to the fish muscle. On the basis of soft parts, concentration of the nuclide closed association among bivalve, gastropod and cephalopod except squid that gave lower values than the others. (author)

  14. Cobalt production in RAPS-1

    International Nuclear Information System (INIS)

    Krishnan, P.D.; Purandare, H.D.

    1978-01-01

    At present in RAPS-1 radioisotope Co 60 is produced by irradiating Co 59 in the adjusters which perform the function of regulation of reactivity, power and xenon override. But the manrem expenditure of the crew handling the charge and discharge of the adjusters is going to be prohibitively high. It is therefore proposed to irradiate Co 59 in the fuel channel positions. The physics optimisation study for such irradiation is presented. The burnup penalty and loss of power are estimated to produce the required quantity of Co 60 after optimising the number of cobalt pencils in a bundle and the positions of the cobalt producing channels in the reactor core. (author)

  15. Progress made by Framatome in neutron flux mapping technology

    International Nuclear Information System (INIS)

    Mourlevat, J.L.

    1999-01-01

    A fixed in-core system based on self-powered neutron detectors (SPNDs) could improve the power distribution measurement accuracy and hence improve core operating margin knowledge. For that purpose, Framatome has tested rhodium neutron detectors as fixed in-core sensors. Two such in-core strings were installed during tie summer of 1997 at Golfech Unit 2, for a three-year experiment. (author)

  16. Cobalt(II) and Cobalt(III) Coordination Compounds.

    Science.gov (United States)

    Thomas, Nicholas C.; And Others

    1989-01-01

    Presents a laboratory experiment which illustrates the formation of tris(phenanthroline)cobalt complexes in the 2+ and 3+ oxidation states, the effect of coordination on reactions of the ligand, and the use of a ligand displacement reaction in recovering the transformed ligand. Uses IR, UV-VIS, conductivity, and NMR. (MVL)

  17. Special methods used in neutron dosimetry

    International Nuclear Information System (INIS)

    Mas, P.

    1975-01-01

    The methods used in radiation reactor dosimetry which do not depend on fission reaction nor foil activation are reviewed. These other techniques are especially the following: the different types of self-powered detectors, with fast or slow response, their characteristics of noise and temperature effect, their practical uses: the damage detectors, considering the variations of their physical properties (resistivity, density, ...) and their use for characterizing the neutron spectra; the little loop with circulating fluids (air, nitrogen, helium, water) [fr

  18. The cobalt-60 container scanner

    International Nuclear Information System (INIS)

    Jigang, A.; Liye, Z.; Yisi, L.; Haifeng, W.; Zhifang, W.; Liqiang, W.; Yuanshi, Z.; Xincheng, X.; Furong, L.; Baozeng, G.; Chunfa, S.

    1997-01-01

    The Institute of Nuclear Energy Technology (INET) has successfully designed and constructed a container (cargo) scanner, which uses cobalt-60 of 100-300 Ci as radiation source. The following performances of the Cobalt-60 container scanner have been achieved at INET: a) IQI (Image Quality Indicator) - 2.5% behind 100 mm of steel; b) CI (Contrast Indicator) - 0.7% behind 100 mm of steel; c) SP (Steel Penetration) - 240 mm of steel; d) Maximum Dose per Scanning - 0.02mGy; e) Throughput - twenty 40-foot containers per hour. These performances are equal or similar to those of the accelerator scanners. Besides these nice enough inspection properties, the Cobalt-60 scanner possesses many other special features which are better than accelerator scanners: a) cheap price - it will be only or two tenths of the accelerator scanner's; b) low radiation intensity - the radiation protection problem is much easier to solve and a lot of money can be saved on the radiation shielding building; c) much smaller area for installation and operation; d) simple operation and convenient maintenance; e) high reliability and stability. The Cobalt-60 container (or cargo) scanner is satisfied for boundary customs, seaports, airports and railway stations etc. Because of the nice special features said above, it is more suitable to be applied widely. Its high properties and low price will make it have much better application prospects

  19. Cobalt 60 commercial irradiation facilities

    International Nuclear Information System (INIS)

    West, G.

    1985-01-01

    The advantage of using cobalt 60 for ionizing treatment is that it has excellent penetration. Gamma plants are also very efficient, in as much as there is very little mechanical or electrical equipment in a gamma irradiation facility. The average efficiency of a gamma plant is usually around 95% of all available processing time

  20. Large Scale Triboelectric Nanogenerator and Self-Powered Flexible Sensor for Human Sleep Monitoring

    Directory of Open Access Journals (Sweden)

    Xiaoheng Ding

    2018-05-01

    Full Text Available The triboelectric nanogenerator (TENG and its application as a sensor is a popular research subject. There is demand for self-powered, flexible sensors with high sensitivity and high power-output for the next generation of consumer electronics. In this study, a 300 mm × 300 mm carbon nanotube (CNT-doped porous PDMS film was successfully fabricated wherein the CNT influenced the micropore structure. A self-powered TENG tactile sensor was established according to triboelectric theory. The CNT-doped porous TENG showed a voltage output seven times higher than undoped porous TENG and 16 times higher than TENG with pure PDMS, respectively. The TENG successfully acquired human motion signals, breath signals, and heartbeat signals during a sleep monitoring experiment. The results presented here may provide an effective approach for fabricating large-scale and low-cost flexible TENG sensors.

  1. ePave: A Self-Powered Wireless Sensor for Smart and Autonomous Pavement.

    Science.gov (United States)

    Xiao, Jian; Zou, Xiang; Xu, Wenyao

    2017-09-26

    "Smart Pavement" is an emerging infrastructure for various on-road applications in transportation and road engineering. However, existing road monitoring solutions demand a certain periodic maintenance effort due to battery life limits in the sensor systems. To this end, we present an end-to-end self-powered wireless sensor-ePave-to facilitate smart and autonomous pavements. The ePave system includes a self-power module, an ultra-low-power sensor system, a wireless transmission module and a built-in power management module. First, we performed an empirical study to characterize the piezoelectric module in order to optimize energy-harvesting efficiency. Second, we developed an integrated sensor system with the optimized energy harvester. An adaptive power knob is designated to adjust the power consumption according to energy budgeting. Finally, we intensively evaluated the ePave system in real-world applications to examine the system's performance and explore the trade-off.

  2. In Vivo Self-Powered Wireless Cardiac Monitoring via Implantable Triboelectric Nanogenerator.

    Science.gov (United States)

    Zheng, Qiang; Zhang, Hao; Shi, Bojing; Xue, Xiang; Liu, Zhuo; Jin, Yiming; Ma, Ye; Zou, Yang; Wang, Xinxin; An, Zhao; Tang, Wei; Zhang, Wei; Yang, Fan; Liu, Yang; Lang, Xilong; Xu, Zhiyun; Li, Zhou; Wang, Zhong Lin

    2016-07-26

    Harvesting biomechanical energy in vivo is an important route in obtaining sustainable electric energy for powering implantable medical devices. Here, we demonstrate an innovative implantable triboelectric nanogenerator (iTENG) for in vivo biomechanical energy harvesting. Driven by the heartbeat of adult swine, the output voltage and the corresponding current were improved by factors of 3.5 and 25, respectively, compared with the reported in vivo output performance of biomechanical energy conversion devices. In addition, the in vivo evaluation of the iTENG was demonstrated for over 72 h of implantation, during which the iTENG generated electricity continuously in the active animal. Due to its excellent in vivo performance, a self-powered wireless transmission system was fabricated for real-time wireless cardiac monitoring. Given its outstanding in vivo output and stability, iTENG can be applied not only to power implantable medical devices but also possibly to fabricate a self-powered, wireless healthcare monitoring system.

  3. Compact self-powered synchronous energy extraction circuit design with enhanced performance

    Science.gov (United States)

    Liu, Weiqun; Zhao, Caiyou; Badel, Adrien; Formosa, Fabien; Zhu, Qiao; Hu, Guangdi

    2018-04-01

    Synchronous switching circuit is viewed as an effective solution of enhancing the generator’s performance and providing better adaptability for load variations. A critical issue for these synchronous switching circuits is the self-powered realization. In contrast with other methods, the electronic breaker possesses the advantage of simplicity and reliability. However, beside the energy consumption of the electronic breakers, the parasitic capacitance decreases the available piezoelectric voltage. In this technical note, a new compact design of the self-powered switching circuit using electronic breaker is proposed. The envelope diodes are excluded and only a single envelope capacitor is used. The parasitic capacitance is reduced to half with boosted performance while the components are reduced with cost saved.

  4. Reviving Vibration Energy Harvesting and Self-Powered Sensing by a Triboelectric Nanogenerator

    KAUST Repository

    Chen, Jun

    2017-10-10

    Vibration energy harvesting and sensing is a traditional and growing research field in which various working mechanisms and designs have been developed for an improved performance. Relying on a coupling effect of contact electrification and electrostatic induction, in the past 5 years, triboelectric nanogenerator (TENG) has been applied as a fundamentally new technology to revive the field of vibration energy harvesting and self-powered sensing, especially for low-frequency vibrations such as human motion, automobile, machine, and bridge vibrations. The demonstrated instantaneous energy conversion efficiency of ∼70% and a total efficiency up to 85% distinguished TENG from traditional techniques. In this article, both TENG-enabled vibration energy harvesting and self-powered active sensing are comprehensively reviewed. Moving toward future development, problems pressing for solutions and onward research directions are also posed to deliver a coherent picture.

  5. An Active Capacitor with Self-Power and Internal Feedback Control Signals

    DEFF Research Database (Denmark)

    Wang, Haoran; Wang, Huai

    2017-01-01

    This paper proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. A control strategy that does not require any external feedback...... signal is proposed and a self-power scheme for gate drivers and the controller is applied to achieve the two-terminal active capacitor. The concept, control method, self-power scheme, efficiency, and impedance characteristics of the active capacitor are presented. A case study of the proposed active...... capacitor for a capacitive DC-link application is discussed. The results reveal a significantly lower overall energy storage of passive elements and a reduced cost to fulfill a specific reliability target, compared to a passive capacitor solution. Proof-of-concept experimental results are given to verify...

  6. Enzymatic Fuel Cells: Towards Self-Powered Implantable and Wearable Diagnostics

    Directory of Open Access Journals (Sweden)

    Carla Gonzalez-Solino

    2018-01-01

    Full Text Available With the rapid progress in nanotechnology and microengineering, point-of-care and personalised healthcare, based on wearable and implantable diagnostics, is becoming a reality. Enzymatic fuel cells (EFCs hold great potential as a sustainable means to power such devices by using physiological fluids as the fuel. This review summarises the fundamental operation of EFCs and discusses the most recent advances for their use as implantable and wearable self-powered sensors.

  7. Threshold self-powered gamma detector for use as a nuclear reactor power monitor

    International Nuclear Information System (INIS)

    LeVert, F.E.

    1977-01-01

    A study of a threshold self-powered gamma detector for use as a nuclear reactor power monitor was conducted. Measurements were performed to ascertain whether certain detector material arrangements could be used to obtain significant discrimination against low energy gammas. Results indicating agreement between detector response and reactor power output are presented. Evidence of rejection of low energy gammas by the detector is presented. The simplicity of construction and ruggedness of the detector are also discussed

  8. Enzymatic Fuel Cells: Towards Self-Powered Implantable and Wearable Diagnostics

    Science.gov (United States)

    Gonzalez-Solino, Carla; Lorenzo, Mirella Di

    2018-01-01

    With the rapid progress in nanotechnology and microengineering, point-of-care and personalised healthcare, based on wearable and implantable diagnostics, is becoming a reality. Enzymatic fuel cells (EFCs) hold great potential as a sustainable means to power such devices by using physiological fluids as the fuel. This review summarises the fundamental operation of EFCs and discusses the most recent advances for their use as implantable and wearable self-powered sensors. PMID:29382147

  9. Enzymatic Fuel Cells: Towards Self-Powered Implantable and Wearable Diagnostics.

    Science.gov (United States)

    Gonzalez-Solino, Carla; Lorenzo, Mirella Di

    2018-01-29

    With the rapid progress in nanotechnology and microengineering, point-of-care and personalised healthcare, based on wearable and implantable diagnostics, is becoming a reality. Enzymatic fuel cells (EFCs) hold great potential as a sustainable means to power such devices by using physiological fluids as the fuel. This review summarises the fundamental operation of EFCs and discusses the most recent advances for their use as implantable and wearable self-powered sensors.

  10. Enzymatic Fuel Cells: Towards Self-Powered Implantable and Wearable Diagnostics

    OpenAIRE

    Carla Gonzalez-Solino; Mirella Di Lorenzo

    2018-01-01

    With the rapid progress in nanotechnology and microengineering, point-of-care and personalised healthcare, based on wearable and implantable diagnostics, is becoming a reality. Enzymatic fuel cells (EFCs) hold great potential as a sustainable means to power such devices by using physiological fluids as the fuel. This review summarises the fundamental operation of EFCs and discusses the most recent advances for their use as implantable and wearable self-powered sensors.

  11. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  12. Code of practice for in-core instrumentation for neutron fluence rate (flux) measurements in power reactors

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    This standard applies to in-core (on-line) neutron detectors and instrumentation which is designed for safety, information or control purposes. It also applies to components in so far as these components are contained within the primary envelope of the reactor. The detector types usually used are dc ionization chambers and self-powered neutron detectors

  13. Triboelectric Nanogenerator Enabled Body Sensor Network for Self-Powered Human Heart-Rate Monitoring.

    Science.gov (United States)

    Lin, Zhiming; Chen, Jun; Li, Xiaoshi; Zhou, Zhihao; Meng, Keyu; Wei, Wei; Yang, Jin; Wang, Zhong Lin

    2017-09-26

    Heart-rate monitoring plays a critical role in personal healthcare management. A low-cost, noninvasive, and user-friendly heart-rate monitoring system is highly desirable. Here, a self-powered wireless body sensor network (BSN) system is developed for heart-rate monitoring via integration of a downy-structure-based triboelectric nanogenerator (D-TENG), a power management circuit, a heart-rate sensor, a signal processing unit, and Bluetooth module for wireless data transmission. By converting the inertia energy of human walking into electric power, a maximum power of 2.28 mW with total conversion efficiency of 57.9% was delivered at low operation frequency, which is capable of immediately and sustainably driving the highly integrated BSN system. The acquired heart-rate signal by the sensor would be processed in the signal process circuit, sent to an external device via the Bluetooth module, and displayed on a personal cell phone in a real-time manner. Moreover, by combining a TENG-based generator and a TENG-based sensor, an all-TENG-based wireless BSN system was developed, realizing continuous and self-powered heart-rate monitoring. This work presents a potential method for personal heart-rate monitoring, featured as being self-powered, cost-effective, noninvasive, and user-friendly.

  14. Novel design of a self powered and self sensing magneto-rheological damper

    International Nuclear Information System (INIS)

    Ferdaus, Mohammad Meftahul; Rashid, M M; Bhuiyan, M M I; Muthalif, Asan Gani Bin Abdul; Hasan, M R

    2013-01-01

    Magneto-rheological (MR) dampers are semi-active control devices and use MR fluids. Magneto-rheological dampers have successful applications in mechatronics engineering, civil engineering and numerous areas of engineering. At present, traditional MR damper systems, require a isolated power supply and dynamic sensor. This paper presents the achievability and accuracy of a self- powered and self-sensing magneto-rheological damper using harvested energy from the vibration and shock environment in which it is deployed and another important part of this paper is the increased yield stress of the Magneto rheological Fluids. Magneto rheological fluids using replacement of glass beads for Magnetic Particles to surge yield stress is implemented here. Clearly this shows better result on yield stress, viscosity, and settling rate. Also permanent magnet generator (PMG) is designed and attached to a MR damper. For evaluating the self-powered MR damper's vibration mitigating capacity, an Engine Mount System using the MR damper is simulated. The ideal stiffness of the PMG for the Engine Mount System (EMS) is calculated by numerical study. The vibration mitigating performance of the EMS employing the self-powered and self sensing MR damper is theoretically calculated and evaluated in the frequency domain

  15. Novel design of a self powered and self sensing magneto-rheological damper

    Science.gov (United States)

    Meftahul Ferdaus, Mohammad; Rashid, M. M.; Bhuiyan, M. M. I.; Muthalif, Asan Gani Bin Abdul; Hasan, M. R.

    2013-12-01

    Magneto-rheological (MR) dampers are semi-active control devices and use MR fluids. Magneto-rheological dampers have successful applications in mechatronics engineering, civil engineering and numerous areas of engineering. At present, traditional MR damper systems, require a isolated power supply and dynamic sensor. This paper presents the achievability and accuracy of a self- powered and self-sensing magneto-rheological damper using harvested energy from the vibration and shock environment in which it is deployed and another important part of this paper is the increased yield stress of the Magneto rheological Fluids. Magneto rheological fluids using replacement of glass beads for Magnetic Particles to surge yield stress is implemented here. Clearly this shows better result on yield stress, viscosity, and settling rate. Also permanent magnet generator (PMG) is designed and attached to a MR damper. For evaluating the self-powered MR damper's vibration mitigating capacity, an Engine Mount System using the MR damper is simulated. The ideal stiffness of the PMG for the Engine Mount System (EMS) is calculated by numerical study. The vibration mitigating performance of the EMS employing the self-powered & self sensing MR damper is theoretically calculated and evaluated in the frequency domain.

  16. A novel integrated self-powered brake system for more electric aircraft

    Directory of Open Access Journals (Sweden)

    Yaoxing SHANG

    2018-05-01

    Full Text Available Traditional hydraulic brake systems require a complex system of pipelines between an aircraft engine driven pump (EDP and brake actuators, which increases the weight of the aircraft and may even cause serious vibration and leakage problems. In order to improve the reliability and safety of more electric aircraft (MEA, this paper proposes a new integrated self-powered brake system (ISBS for MEA. It uses a hydraulic pump geared to the main wheel to recover a small part of the kinetic energy of a landing aircraft. The recovered energy then serves as the hydraulic power supply for brake actuators. It does not require additional hydraulic source, thus removing the pipelines between an EDP and brake actuators. In addition, its self-powered characteristic makes it possible to brake as usual even in an emergency situation when the airborne power is lost. This paper introduces the working principle of the ISBS and presents a prototype. The mathematical models of a taxiing aircraft and the ISBS are established. A feedback linearization control algorithm is designed to fulfill the anti-skid control. Simulations are carried out to verify the feasibility of the ISBS, and experiments are conducted on a ground inertia brake test bench. The ISBS presents a good performance and provides a new potential solution in the field of brake systems for MEA. Keywords: Hydraulic, Feedback linearization control, More electric aircraft, Novel brake system, Self-powered

  17. Fast neutron sensitivity of polymer dosemeters

    International Nuclear Information System (INIS)

    Harper, M.W.; Pearson, D.W.; Moran, P.R.

    1975-01-01

    The responses of polymer thermocurrent dosemeters to fission spectrum and 14 MeV neutrons were measured. The dosemeters are in the form of disks 1 cm diam by 0.5 mm thick. Relative to Cobalt 60 gamma responses, teflon PTFE dosemeters show a 6 percent response to 14 MeV neutrons and a 5 percent response to fission neutrons on a tissue rad basis. Polymethylpentene dosemeters show a 49 percent response to 14 MeV neutrons and a 40 percent response to fission neutrons on a tissue rad basis when provided with adequate recoil proton buildup. The sensitivity of these dosemeters is limited to neutron doses greater than 10 rads by spurious background currents

  18. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  19. Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?

    Science.gov (United States)

    Thyssen, Jacob Pontoppidan; Jellesen, Morten S; Menné, Torkil; Lidén, Carola; Julander, Anneli; Møller, Per; Johansen, Jeanne Duus

    2010-08-01

    Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure. The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. The cobalt spot test was used to assess cobalt release from all items. Microstructural characterization was made using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). Cobalt release was found in 4 (1.1%) of 354 items. All these had a dark appearance. SEM/EDS was performed on the four dark appearing items which showed tin-cobalt plating on these. This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future. Industries may not be fully aware of the potential cobalt allergy problem.

  20. Design and fabrication of self-powered micro-harvesters rotating and vibrated micro-power systems

    CERN Document Server

    Pan, C T; Lin, Liwei; Chen, Ying-Chung

    2013-01-01

    Presents the latest methods for designing and fabricating self-powered micro-generators and energy harvester systems Design and Fabrication of Self-Powered Micro-Harvesters introduces the latest trends of self-powered generators and energy harvester systems, including the design, analysis and fabrication of micro power systems. Presented in four distinct parts, the authors explore the design and fabrication of: vibration-induced electromagnetic micro-generators; rotary electromagnetic micro-generators; flexible piezo-micro-generator with various widths; and PVDF electrospunpiezo-energy with

  1. Polytypic transformations during the thermal decomposition of cobalt hydroxide and cobalt hydroxynitrate

    International Nuclear Information System (INIS)

    Ramesh, Thimmasandra Narayan

    2010-01-01

    The isothermal decomposition of cobalt hydroxide and cobalt hydroxynitrate at different intervals of temperature leads to the formation of Co 3 O 4 . The phase evolution during the decomposition process was monitored using powder X-ray diffraction. The transformation of cobalt hydroxide to cobalt oxide occurs via three phase mixture while cobalt hydroxynitrate to cobalt oxide occurs through a two phase mixture. The nature of the sample and its preparation method controls the decomposition mechanism. The comparison of topotactical relationship between the precursors to the decomposed product has been reported in relation to polytypism. - Graphical abstract: Isothermal thermal decomposition studies of cobalt hydroxide and cobalt hydroxynitrate at different intervals of temperature show the metastable phase formed prior to Co 3 O 4 phase.

  2. Recovery of Cobalt as Cobalt Oxalate from Cobalt Tailings Using Moderately Thermophilic Bioleaching Technology and Selective Sequential Extraction

    Directory of Open Access Journals (Sweden)

    Guobao Chen

    2016-07-01

    Full Text Available Cobalt is a very important metal which is widely applied in various critical areas, however, it is difficult to recover cobalt from minerals since there is a lack of independent cobalt deposits in nature. This work is to provide a complete process to recover cobalt from cobalt tailings using the moderately thermophilic bioleaching technology and selective sequential extraction. It is found that 96.51% Co and 26.32% Cu were extracted after bioleaching for four days at 10% pulp density. The mean compositions of the leach solutions contain 0.98 g·L−1 of Co, 6.52 g·L−1 of Cu, and 24.57 g·L−1 of Fe (III. The copper ion was then recovered by a solvent extraction process and the ferric ions were selectively removed by applying a goethite deironization process. The technological conditions of the above purification procedures were deliberately discussed. Over 98.6% of copper and 99.9% of ferric ions were eliminated from the leaching liquor. Cobalt was finally produced as cobalt oxalate and its overall recovery during the whole process was greater than 95%. The present bioleaching process of cobalt is worth using for reference to deal with low-grade cobalt ores.

  3. Sorption of cobalt in zeolites and natural clays of the clinoptilolite and kaolinite type

    International Nuclear Information System (INIS)

    Davila R, J.I.; Solache R, M.

    2006-01-01

    In this work the sorption of cobalt of aqueous solutions in two natural zeolites (clinoptilolite) and a clay (kaolinite) of origin in the center-north region of Mexico is evaluated. The effect of the pH and the time of contact in the process of sorption were evaluated. The cobalt retained in the aluminosilicates was determined by neutron activation analysis. The cobalt sorption in the materials in a range of pH from 4 to 7 does not present significant variations. The studies of reaction kinetics show a very fast sorption in the first 5 hours of contact, reaching the equilibrium in approximately 24 hours. The kinetics of sorption of the cobalt ions was represented better by the Ritchie reaction model modified of second order. The experimental data for the zeolites obtained at ambient temperature and varying the concentration were adjusted to the models of Freundlich, Langmuir and Freundlich-Langmuir isotherms and it was observed that the cobalt sorption it behaves according to the Freundlich isotherm model. (Author)

  4. Derivative spectrophotometry of cobalt alloys

    International Nuclear Information System (INIS)

    Spitsyn, P.K.

    1985-01-01

    The method of derivative spectrophotometry is briefly described, and derivative absorption spectra are presented for samarium, cobalt, and commercial Sm-Co alloys. It is shown that the use of derivative spectrophotometry not only improves the accuracy and selectivity of element determinations but also simplifies the analysis of alloys. Results of a statistical evaluation of the metrological characteristics of the analytical procedure described here are presented. 8 references

  5. Cobalt accumulation and circulation by blackgum trees

    International Nuclear Information System (INIS)

    Thomas, W.A.

    1975-01-01

    Blackgum (Nyssa sylvatica Marsh.) trees accumulate far greater concentrations of cobalt in mature foliage than do other species on the same site (363 ppM in ash of blackgum, compared with about 3 ppM by mockernut hickory and about 1 ppM by red maple, tulip tree, and white oak). Cobalt concentrations in dormant woody tissues of blackgum also significantly exceed those in the other four species. Inoculation of six blackgums with 60 Co revealed that cobalt remains mobile in the trees for at least 3 years. Foliar concentrations of stable cobalt increase uniformly until senescence. In late August, foliage accounts for only 9 percent of total tree weight but 57 percent of total tree cobalt. Losses of cobalt from trees occur almost entirely by leaf abscission, and the loss rates of weight and cobalt from decomposing litter are similar. Retention of cobalt in the biologically active soil layers perpetuates zones of cobalt concentration created by this species in woodlands

  6. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  7. Phase-transformation and subgrain-deformation characteristics in a cobalt-based superalloy

    International Nuclear Information System (INIS)

    Benson, M.L.; Reetz, B.; Liaw, P.K.; Reimers, W.; Choo, H.; Brown, D.W.; Saleh, T.A.; Klarstrom, D.L.

    2011-01-01

    Research highlights: → The mechanical behavior of a cobalt-based superalloy was investigated. → Two diffraction techniques were used to study deformation mechanisms of materials. → In-situ neutron diffraction provides the volume-averaged information. → The peak-profile analysis reveals the information on a subgrain level. → The material exhibited a transformation texture for the HCP phase under loading. - Abstract: A complimentary set of experiments, in situ neutron diffraction and ex situ synchrotron X-ray diffraction, were used to study the phase-transformation and subgrain-deformation characteristics of a cobalt-based superalloy. The neutron diffraction indicated a strain-induced phase transformation in the cobalt-based superalloy under uniaxial tension and compression. The synchrotron X-ray diffraction revealed stacking-fault accumulation and twinning under the same loading conditions. The extent of transformation was found to be greater under tension than under compression. Tensile plastic strains below 2% were accommodated by the stacking-fault creation, while those greater than 2% were accommodated by the phase transformation. Twinning was found to be more active under compressive loading than under tensile loading.

  8. Fiber-based all-solid-state flexible supercapacitors for self-powered systems.

    Science.gov (United States)

    Xiao, Xu; Li, Tianqi; Yang, Peihua; Gao, Yuan; Jin, Huanyu; Ni, Weijian; Zhan, Wenhui; Zhang, Xianghui; Cao, Yuanzhi; Zhong, Junwen; Gong, Li; Yen, Wen-Chun; Mai, Wenjie; Chen, Jian; Huo, Kaifu; Chueh, Yu-Lun; Wang, Zhong Lin; Zhou, Jun

    2012-10-23

    All-solid-state flexible supercapacitors based on a carbon/MnO(2) (C/M) core-shell fiber structure were fabricated with high electrochemical performance such as high rate capability with a scan rate up to 20 V s(-1), high volume capacitance of 2.5 F cm(-3), and an energy density of 2.2 × 10(-4) Wh cm(-3). By integrating with a triboelectric generator, supercapacitors could be charged and power commercial electronic devices, such as a liquid crystal display or a light-emitting-diode, demonstrating feasibility as an efficient storage component and self-powered micro/nanosystems.

  9. Self-powered information measuring wireless networks using the distribution of tasks within multicore processors

    Science.gov (United States)

    Zhuravska, Iryna M.; Koretska, Oleksandra O.; Musiyenko, Maksym P.; Surtel, Wojciech; Assembay, Azat; Kovalev, Vladimir; Tleshova, Akmaral

    2017-08-01

    The article contains basic approaches to develop the self-powered information measuring wireless networks (SPIM-WN) using the distribution of tasks within multicore processors critical applying based on the interaction of movable components - as in the direction of data transmission as wireless transfer of energy coming from polymetric sensors. Base mathematic model of scheduling tasks within multiprocessor systems was modernized to schedule and allocate tasks between cores of one-crystal computer (SoC) to increase energy efficiency SPIM-WN objects.

  10. Paper-based origami triboelectric nanogenerators and self-powered pressure sensors

    KAUST Repository

    Yang, Pokang

    2015-01-27

    Discovering renewable and sustainable power sources is indispensable for the development of green electronics and sensor networks. In this paper, we present origami triboelectric nanogenerators (TENGs) using paper as the starting material, with a high degree of flexibility, light weight, low cost, and recyclability. Slinky- and doodlebug-shaped TENGs can be easily fabricated by properly folding printer papers. The as-fabricated TENGs are capable of harvesting ambient mechanical energy from various kinds of human motions, such as stretching, lifting, and twisting. The generated electric outputs have been used to directly light-up commercial LEDs. In addition, the as-fabricated TENGs can also serve as self-powered pressure sensors.

  11. Self-powered remotely controlled machines and tools for safety improvement in mining

    Energy Technology Data Exchange (ETDEWEB)

    Mirzaeva, G. [University of Newcastle, Callaghan, NSW (Australia)

    2005-07-01

    This paper addresses the problem of meeting the safety requirements of mining industry for implementation of control and monitoring equipment without external wiring. Local power generation and accumulation combined with remote control and wireless data transmission are suggested as an appropriate way to make the implementation of such device safe and convenient, which in its turn would facilitate their wider application for automation and safety improvement. A rope shovel dipper trip system is discussed in detail as an example of a self-powered remotely-controlled system. Other possible applications of the concept are also identified, such as Armoured Face Conveyor (AFC) and water jet drilling operation monitoring. 5 refs., 6 figs.

  12. Innovative self-powered submersible microbial electrolysis cell (SMEC) for biohydrogen production from anaerobic reactors

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2012-01-01

    A self-powered submersible microbial electrolysis cell (SMEC), in which a specially designed anode chamber and external electricity supply were not needed, was developed for in situ biohydrogen production from anaerobic reactors. In batch experiments, the hydrogen production rate reached 17.8 m...... improvement of voltage output and reduction of electron losses were essential for efficient hydrogen generation. In addition, alternate exchanging the electricity-assisting and hydrogen-producing function between the two cell units of the SMEC was found to be an effective approach to inhibit methanogens...

  13. Composite space charge density functions for the calculation of gamma sensitivity of self-powered neutron detectors, using Warren's model

    Science.gov (United States)

    Mahant, A. K.; Rao, P. S.; Misra, S. C.

    1994-07-01

    In the calculational model developed by Warren and Shah for the computation of the gamma sensitivity ( Sγ) it has been observed that the computed Sγ value is quite sensitive to the space charge distribution function assumed for the insulator region and the energy of the gamma photons. The Sγ of SPNDs with Pt, Co and V emitters (manufactured by Thermocoax, France) has been measured at 60Co photon energy and a good correlation between the measured and computed values has been obtained using a composite space charge density function (CSCD), the details of which are presented in this paper. The arguments are extended for evaluating the Sγ values of several SPNDs for which Warren and Shah reported the measured values for a prompt fission gamma spectrum obtained in a swimming pool reactor. These results are also discussed.

  14. Cobalt 60 availability for radiation processing

    International Nuclear Information System (INIS)

    Fraser, F.M.

    1986-01-01

    In the last 20 years, the steady and significant growth in the application of radiation processing to industrial sterilization has been seen. The principal application of this technology is the sterilization of disposable medical products, food irradiation, the irradiation of personal care goods and so on. At present, more than 70 million curies of cobalt-60 supplied by Atomic Energy of Canada Ltd. have been used for gamma processing in these applications. This is estimated to be more than 80 % of the total cobalt-60 in service in the world. Commercial food irradiation has an exciting future, and as to the impact of food irradiation on the availability of cobalt-60 over the next ten years, two principal factors must be examined, namely, the anticipated demand for cobalt-60 in all radiation processing applications, and the supply of cobalt-60 to reliably meet the expected demand. As for the cobalt-60 in service today, 90 % is used for the sterilization of disposable medical products, 5 % for food irradiation, and 5 % for other application. The demand for up to 30 million curies of cobalt-60 is expected over the next 10 years. Today, it is estimated that over 150,000 tons of spices, fruit and fish are irradiated. The potential cobalt-60 production could exceed 110 million curies per year. Gamma processing application will demand nearly 50 million curies in 1990. (Kako, I.)

  15. Cobalt allergy in hard metal workers

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, T; Rystedt, I

    1983-03-01

    Hard metal contains about 10% cobalt. 853 hard metal workers were examined and patch tested with substances from their environment. Initial patch tests with 1% cobalt chloride showed 62 positive reactions. By means of secondary serial dilution tests, allergic reactions to cobalt were reproduced in 9 men and 30 women. Weak reactions could not normally be reproduced. A history of hand eczema was found in 36 of the 39 individuals with reproducible positive test reactions to cobalt, while 21 of 23 with a positive initial patch test but negative serial dilution test had never had any skin problems. Hand etching and hand grinding, mainly female activities and traumatic to the hands, were found to involve the greatest risk of cobalt sensitization. 24 individuals had an isolated cobalt allergy. They had probably been sensitized by hard metal work, while the individuals, all women, who had simultaneous nickel allergy had probably been sensitized to nickel before their employment and then became sensitized to cobalt by hard metal work. A traumatic occupation, which causes irritant contact dermatitis and/or a previous contact allergy or atopy is probably a prerequisite for the development of cobalt allergy.

  16. A novel self-powered MR damper: theoretical and experimental analysis

    International Nuclear Information System (INIS)

    Xinchun, Guan; Hui, Li; Jinping, Ou; Yonghu, Huang; Yi, Ru

    2015-01-01

    This paper presents a novel magnetorheological (MR) damper with a self-powered capability, which is proposed to have energy harvesting and MR damping technologies integrated into a single device. Vibration energy harvesting mechanisms were adopted, based on ball-screw mechanisms and a rotary permanent magnet dc generator, to convert the external vibration energy into electrical energy to power the MR damping unit. The configuration and operating principles of the proposed self-powered MR damper were presented. Considering the core loss effect on the magnetic field, a theoretical analysis of the proposed MR damper was carried out and a mechanical model was developed. Finally, a prototype with a capacity of 10 kN was fabricated and experimentally investigated in both the direct-supply mode and the supply-with-rectifier mode. The results indicated that the proposed configuration is feasible and that both modes can realize good self-adaptability of the MR damping force. However, the direct-supply mode has a sag effect in the force–displacement curve and provides a lower energy-dissipating capacity than the direct-supply mode does under the same conditions. (paper)

  17. Air-Flow-Driven Triboelectric Nanogenerators for Self-Powered Real-Time Respiratory Monitoring.

    Science.gov (United States)

    Wang, Meng; Zhang, Jiahao; Tang, Yingjie; Li, Jun; Zhang, Baosen; Liang, Erjun; Mao, Yanchao; Wang, Xudong

    2018-06-04

    Respiration is one of the most important vital signs of humans, and respiratory monitoring plays an important role in physical health management. A low-cost and convenient real-time respiratory monitoring system is extremely desirable. In this work, we demonstrated an air-flow-driven triboelectric nanogenerator (TENG) for self-powered real-time respiratory monitoring by converting mechanical energy of human respiration into electric output signals. The operation of the TENG was based on the air-flow-driven vibration of a flexible nanostructured polytetrafluoroethylene (n-PTFE) thin film in an acrylic tube. This TENG can generate distinct real-time electric signals when exposed to the air flow from different breath behaviors. It was also found that the accumulative charge transferred in breath sensing corresponds well to the total volume of air exchanged during the respiration process. Based on this TENG device, an intelligent wireless respiratory monitoring and alert system was further developed, which used the TENG signal to directly trigger a wireless alarm or dial a cell phone to provide timely alerts in response to breath behavior changes. This research offers a promising solution for developing self-powered real-time respiratory monitoring devices.

  18. Personalized keystroke dynamics for self-powered human--machine interfacing.

    Science.gov (United States)

    Chen, Jun; Zhu, Guang; Yang, Jin; Jing, Qingshen; Bai, Peng; Yang, Weiqing; Qi, Xuewei; Su, Yuanjie; Wang, Zhong Lin

    2015-01-27

    The computer keyboard is one of the most common, reliable, accessible, and effective tools used for human--machine interfacing and information exchange. Although keyboards have been used for hundreds of years for advancing human civilization, studying human behavior by keystroke dynamics using smart keyboards remains a great challenge. Here we report a self-powered, non-mechanical-punching keyboard enabled by contact electrification between human fingers and keys, which converts mechanical stimuli applied to the keyboard into local electronic signals without applying an external power. The intelligent keyboard (IKB) can not only sensitively trigger a wireless alarm system once gentle finger tapping occurs but also trace and record typed content by detecting both the dynamic time intervals between and during the inputting of letters and the force used for each typing action. Such features hold promise for its use as a smart security system that can realize detection, alert, recording, and identification. Moreover, the IKB is able to identify personal characteristics from different individuals, assisted by the behavioral biometric of keystroke dynamics. Furthermore, the IKB can effectively harness typing motions for electricity to charge commercial electronics at arbitrary typing speeds greater than 100 characters per min. Given the above features, the IKB can be potentially applied not only to self-powered electronics but also to artificial intelligence, cyber security, and computer or network access control.

  19. Waterproof and stretchable triboelectric nanogenerator for biomechanical energy harvesting and self-powered sensing

    Science.gov (United States)

    Chen, Xuexian; Miao, Liming; Guo, Hang; Chen, Haotian; Song, Yu; Su, Zongming; Zhang, Haixia

    2018-05-01

    We introduce a waterproof and stretchable triboelectric nanogenerator (TENG) that can be attached on the human body, such as fingers and the wrist, to harvest mechanical energy from body movement. The whole device is composed of stretchable material, making it able to endure diverse mechanical deformations and scavenge energy from them. Under gentle mechanical motions of pressing, stretching and bending, the device with an effective area of 1 × 2 cm2 can generate the peak-to-peak output current of 257.5 nA, 50.2 nA, and 33.5 nA, respectively. Besides, the TENG is tightly encapsulated, enabling it to avoid the influence of the external environment like humidity changes and harvest energy under water. Particularly, owing to the thin and soft properties of the encapsulation film, the device can respond to weak vibrations like the wrist pulse and act as a self-powered pulse sensor, which broadens its application prospects in the field of wearable energy harvesting devices and self-powered sensing systems.

  20. Thermally Driven Transport and Relaxation Switching Self-Powered Electromagnetic Energy Conversion.

    Science.gov (United States)

    Cao, Maosheng; Wang, Xixi; Cao, Wenqiang; Fang, Xiaoyong; Wen, Bo; Yuan, Jie

    2018-06-07

    Electromagnetic energy radiation is becoming a "health-killer" of living bodies, especially around industrial transformer substation and electricity pylon. Harvesting, converting, and storing waste energy for recycling are considered the ideal ways to control electromagnetic radiation. However, heat-generation and temperature-rising with performance degradation remain big problems. Herein, graphene-silica xerogel is dissected hierarchically from functions to "genes," thermally driven relaxation and charge transport, experimentally and theoretically, demonstrating a competitive synergy on energy conversion. A generic approach of "material genes sequencing" is proposed, tactfully transforming the negative effects of heat energy to superiority for switching self-powered and self-circulated electromagnetic devices, beneficial for waste energy harvesting, conversion, and storage. Graphene networks with "well-sequencing genes" (w = P c /P p > 0.2) can serve as nanogenerators, thermally promoting electromagnetic wave absorption by 250%, with broadened bandwidth covering the whole investigated frequency. This finding of nonionic energy conversion opens up an unexpected horizon for converting, storing, and reusing waste electromagnetic energy, providing the most promising way for governing electromagnetic pollution with self-powered and self-circulated electromagnetic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Self-powered and broadband photodetectors based on graphene/ZnO/silicon triple junctions

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Ching-Cheng; Liao, Yu-Ming; Chen, Yang-Fang, E-mail: yfchen@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Zhan, Jun-Yu; Lin, Tai-Yuan [Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China); Hsieh, Ya-Ping [Graduate Institute of Opto-Mechatronics, National Chung Cheng University, Chia-Yi 621, Taiwan (China)

    2016-08-01

    A self-powered photodetector with ultrahigh sensitivity, fast photoresponse, and wide spectral detectivity covering from 1000 nm to 400 nm based on graphene/ZnO/Si triple junctions has been designed, fabricated, and demonstrated. In this device, graphene serves as a transparent electrode as well as an efficient collection layer for photogenerated carriers due to its excellent tunability of Fermi energy. The ZnO layer acts as an antireflection layer to trap the incident light and enhance the light absorption. Furthermore, the insertion of the ZnO layer in between graphene and Si layers can create build-in electric field at both graphene/ZnO and ZnO/Si interfaces, which can greatly enhance the charge separation of photogenerated electron and hole pairs. As a result, the sensitivity and response time can be significantly improved. It is believed that our methodology for achieving a high-performance self-powered photodetector based on an appropriate design of band alignment and optical parameters can be implemented to many other material systems, which can be used to generate unique optoelectronic devices for practical applications.

  2. Nanostructured Bulk Thermoelectric Generator for Efficient Power Harvesting for Self-powered Sensor Networks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanliang [Idaho National Lab. (INL), Idaho Falls, ID (United States); Butt, Darryl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-07-01

    The objective of this Nuclear Energy Enabling Technology research project is to develop high-efficiency and reliable thermoelectric generators for self-powered wireless sensors nodes utilizing thermal energy from nuclear plant or fuel cycle. The power harvesting technology has crosscutting significance to address critical technology gaps in monitoring nuclear plants and fuel cycle. The outcomes of the project will lead to significant advancement in sensors and instrumentation technology, reducing cost, improving monitoring reliability and therefore enhancing safety. The self-powered wireless sensor networks could support the long-term safe and economical operation of all the reactor designs and fuel cycle concepts, as well as spent fuel storage and many other nuclear science and engineering applications. The research is based on recent breakthroughs in high-performance nanostructured bulk (nanobulk) thermoelectric materials that enable high-efficiency direct heat-to-electricity conversion over a wide temperature range. The nanobulk thermoelectric materials that the research team at Boise State University and University of Houston has developed yield up to a 50% increase in the thermoelectric figure of merit, ZT, compared with state-of-the-art bulk counterparts. This report focuses on the selection of optimal thermoelectric materials for this project. The team has performed extensive study on two thermoelectric materials systems, i.e. the half-Heusler materials, and the Bismuth-Telluride materials. The report contains our recent research results on the fabrication, characterization and thermoelectric property measurements of these two materials.

  3. Self-Powered Wearable Electronics Based on Moisture Enabled Electricity Generation.

    Science.gov (United States)

    Shen, Daozhi; Xiao, Ming; Zou, Guisheng; Liu, Lei; Duley, Walter W; Zhou, Y Norman

    2018-03-24

    Most state-of-the-art electronic wearable sensors are powered by batteries that require regular charging and eventual replacement, which would cause environmental issues and complex management problems. Here, a device concept is reported that can break this paradigm in ambient moisture monitoring-a new class of simple sensors themselves can generate moisture-dependent voltage that can be used to determine the ambient humidity level directly. It is demonstrated that a moisture-driven electrical generator, based on the diffusive flow of water in titanium dioxide (TiO 2 ) nanowire networks, can yield an output power density of up to 4 µW cm -2 when exposed to a highly moist environment. This performance is two orders of magnitude better than that reported for carbon-black generators. The output voltage is strongly dependent on humidity of ambient environment. As a big breakthrough, this new type of device is successfully used as self-powered wearable human-breathing monitors and touch pads, which is not achievable by any existing moisture-induced-electricity technology. The availability of high-output self-powered electrical generators will facilitate the design and application of a wide range of new innovative flexible electronic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Beta-delayed gamma and neutron emission near the double shell closure at 78Ni

    International Nuclear Information System (INIS)

    Rykaczewski, Krzysztof Piotr; Mazzocchi, C.; Grzywacz, R.; Batchelder, J. C.; Bingham, C.R.; Fong, D.; Hamilton, J.H.; Hwang, J.K.; Karny, M.; Krolas, W.; Liddick, S. N.; Morton, A. C.; Mantica, P. F.; Mueller, W. F.; Steiner, M.; Stolz, A.; Winger, J.A.

    2005-01-01

    An experiment was performed at the National Superconducting Cyclotron Laboratory at Michigan State University to investigate β decay of very neutron-rich cobalt isotopes. Beta-delayed neutron emission from 71-74 Co has been observed for the first time. Preliminary results are reported

  5. Cobalt sorption onto Savannah River Plant soils

    International Nuclear Information System (INIS)

    Hoeffner, S.L.

    1985-06-01

    A laboratory study of cobalt-60 sorption was conducted using Savannah River Plant soil and groundwater from the low-level waste burial ground. Systematic variation of soil and water composition indicates that cobalt sorption is most strongly a function of pH. Over a pH range of 2 to 9, the distribution coefficient ranged from 2 to more than 10,000 mL/g. Changes in clay content and in K + , Ca 2+ , or Mg 2+ concentrations influence cobalt sorption indirectly through the slight pH changes which result. The ions Na + , Cl - , and NO 3 - have no effect on cobalt sorption. Ferrous ion, added to groundwater to simulate the condition of water at the bottom of the waste trenches, accounts for part of the decrease in cobalt sorption observed with trench waters. 17 refs., 3 figs., 4 tabs

  6. Experimental evaluation of a self-powered smart damping system in reducing vibrations of a full-scale stay cable

    International Nuclear Information System (INIS)

    Kim, In-Ho; Jung, Hyung-Jo; Koo, Jeong-Hoi

    2010-01-01

    This paper investigates the effectiveness of a self-powered smart damping system consisting of a magnetorheological (MR) damper and an electromagnetic induction (EMI) device in reducing cable vibrations. The proposed smart damping system incorporates an EMI device, which is capable of converting vibration energy into useful electrical energy. Thus, the incorporated EMI device can be used as an alternative power source for the MR damper, making it a self-powering system. The primary goal of this experimental study is to evaluate the performance of the proposed smart damping system using a full-scale, 44.7 m long, high-tension cable. To this end, an EMI part and an MR damper were designed and manufactured. Using a cable test setup in a laboratory setting, a series of tests were performed to evaluate the effectiveness of the self-powered smart damping system in reducing free vibration responses of the cable. The performances of the proposed smart damping system are compared with those of an equivalent passive system. Moreover, the damping characteristics of the smart damping system and the passive system are compared. The experimental results show that the self-powered smart damping system outperforms the passive control cases in reducing the vibrations of the cable. The results also show that the EMI can operate the smart damping system as a sole power source, demonstrating the feasibility of the self-powering capability of the system

  7. SELF-POWERED WIRELESS SENSOR NODE POWER MODELING BASED ON IEEE 802.11 COMMUNICATION PROTOCOL

    Energy Technology Data Exchange (ETDEWEB)

    Vivek Agarwal; Raymond A. DeCarlo; Lefteri H. Tsoukalas

    2016-04-01

    Design and technical advancements in sensing, processing, and wireless communication capabilities of small, portable devices known as wireless sensor nodes (WSNs) have drawn extensive research attention and are vastly applied in science and engineering applications. The WSNs are typically powered by a chemical battery source that has a load dependent finite lifetime. Most applications, including the nuclear industry applications, require WSNs to operate for an extended period of time beginning with their deployment. To ensure longevity, it is important to develop self-powered WSNs. The benefit of self-powered WSNs goes far beyond the cost savings of removing the need for cable installation and maintenance. Self-powered WSNs will potentially offer significant expansion in remote monitoring of nuclear facilities, and provide important data on plant equipment and component status during normal operation, as well as in case of abnormal operation, station blackouts or post-accident evaluation. Advancements in power harvesting technologies enable electric energy generation from many sources, including kinetic, thermal, and radiated energy. For the ongoing research at Idaho National Laboratory, a solid-state thermoelectric-based technology, the thermoelectric generator (TEG), is used to convert thermal energy to power a WSN. The design and development of TEGs to power WSNs that would remain active for a long period of time requires comprehensive understanding of WSN operational. This motivates the research in modeling the lifetime, i.e., power consumption, of a WSN by taking into consideration various node and network level activities. A WSN must perform three essential tasks: sense events, perform quick local information processing of sensed events, and wirelessly exchange locally processed data with the base station or with other WSNs in the network. Each task has a power cost per unit tine and an additional cost when switching between tasks. There are number of other

  8. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  9. Nickel acts as an adjuvant during cobalt sensitization

    DEFF Research Database (Denmark)

    Bonefeld, Charlotte Menne; Nielsen, Morten Milek; Vennegaard, Marie T.

    2015-01-01

    Metal allergy is the most frequent form of contact allergy with nickel and cobalt being the main culprits. Typically, exposure comes from metal-alloys where nickel and cobalt co-exist. Importantly, very little is known about how co-exposure to nickel and cobalt affects the immune system. We...... investigated these effects by using a recently developed mouse model. Mice were epicutaneously sensitized with i) nickel alone, ii) nickel in the presence of cobalt, iii) cobalt alone, or iv) cobalt in the presence of nickel, and then followed by challenge with either nickel or cobalt alone. We found...... that sensitization with nickel alone induced more local inflammation than cobalt alone as measured by increased ear-swelling. Furthermore, the presence of nickel during sensitization to cobalt led to a stronger challenge response to cobalt as seen by increased ear-swelling and increased B and T cell responses...

  10. Equipment for thermal neutron flux measurements in reactor R2

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, E; Nilsson, T; Claeson, S

    1960-04-15

    For most of the thermal neutron flux measurements in reactor R2 cobalt wires will be used. The loading and removal of these wires from the reactor core will be performed by means of a long aluminium tube and electromagnets. After irradiation the wires will be scanned in a semi-automatic device.

  11. Self-Powered Wireless Sensor Network for Automated Corrosion Prediction of Steel Reinforcement

    Directory of Open Access Journals (Sweden)

    Dan Su

    2018-01-01

    Full Text Available Corrosion is one of the key issues that affect the service life and hinders wide application of steel reinforcement. Moreover, corrosion is a long-term process and not visible for embedded reinforcement. Thus, this research aims at developing a self-powered smart sensor system with integrated innovative prediction module for forecasting corrosion process of embedded steel reinforcement. Vibration-based energy harvester is used to harvest energy for continuous corrosion data collection. Spatial interpolation module was developed to interpolate corrosion data at unmonitored locations. Dynamic prediction module is used to predict the long-term corrosion based on collected data. Utilizing this new sensor network, the corrosion process can be automated predicted and appropriate mitigation actions will be recommended accordingly.

  12. Self Powered Non-Dispersive Infra-Red CO{sub 2} Gas Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, D R; MacGregor, C, E-mail: des@gassensing.co.uk [Gas Sensing Solutions Ltd, 60 Grayshill Road, Westfield North Courtyard, Glasgow G68 9HQ (United Kingdom)

    2011-08-17

    This paper describes a non-dispersive infra-red CO{sub 2} gas sensor, incorporating a mid-infra-red solid state light source/ detector combination, tuned to match the spectral absorption characteristic of CO{sub 2} gas. Injection moulded optics provide low cost manufacture. Continuous operation power consumption is < 3.5mW and pulsed mode with energy per measurement < 6mJ. Self powered operation using a solar cell is demonstrated together with wireless capability. Performance of two path length variants (20mm and 70mm) is described. The sensor shows invariant temperature output characteristic from -25 to 50 deg. C. Accuracy level is typically {+-}3% of reading.

  13. Power management circuits for self-powered systems based on micro-scale solar energy harvesting

    Science.gov (United States)

    Yoon, Eun-Jung; Yu, Chong-Gun

    2016-03-01

    In this paper, two types of power management circuits for self-powered systems based on micro-scale solar energy harvesting are proposed. First, if a solar cell outputs a very low voltage, less than 0.5 V, as in miniature solar cells or monolithic integrated solar cells, such that it cannot directly power the load, a voltage booster is employed to step up the solar cell's output voltage, and then a power management unit (PMU) delivers the boosted voltage to the load. Second, if the output voltage of a solar cell is enough to drive the load, the PMU directly supplies the load with solar energy. The proposed power management systems are designed and fabricated in a 0.18-μm complementary metal-oxide-semiconductor process, and their performances are compared and analysed through measurements.

  14. On-power verification of the dynamic response of self-powered in-core detectors

    International Nuclear Information System (INIS)

    Serdula, K.; Beaudet, M.

    1996-01-01

    Self-powered in-core detectors are used for on-line safety and regulation purposes in CANDU reactors. Such applications require use of detectors whose response is primarily prompt to changes in flux. In-service verification of the detectors' response is required to ensure significant degradation in performance has not occurred during long-term operation. Changes in the detector characteristics occur due to nuclear interactions and failures. Present verification requires significant station resources and disrupts power production. Use of the 'noise' in the detector signal is being investigated as an alternative to assess the dynamic response of the detectors during long-term operation. Measurements of reference 'signatures' were obtained from replacement shutdown system detectors. Results show 'noise' measurements are a promising alternative to the current verification method. Identification of changes in the detector response function assist in accurate diagnosis and prognosis of changes in detector signals due to process changes. (author)

  15. Biofuel cell based self-powered sensing platform for L-cysteine detection.

    Science.gov (United States)

    Hou, Chuantao; Fan, Shuqin; Lang, Qiaolin; Liu, Aihua

    2015-03-17

    L-cysteine (L-Cys) detection is of great importance because of its crucial roles in physiological and clinical diagnoses. In this study, a glucose/O2 biofuel cell (BFC) was assembled by using flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH)-based bioanode and laccase-based biocathode. Interestingly, the open circuit potential (OCP) of the BFC could be inhibited by Cu(2+) and subsequently activated by L-Cys, by which a BFC-based self-powered sensing platform for the detection of L-Cys was proposed. The FAD-GDH activity can be inhibited by Cu(2+) and, in turn, subsequent reversible activation by L-Cys because of the binding preference of L-Cys toward Cu(2+) by forming the Cu-S bond. The preferential interaction between L-Cys and Cu(2+) facilitated Cu(2+) to remove from the surface of the bioanode, and thus, the OCP of the system could be turned on. Under optimized conditions, the OCP of the BFC was systematically increased upon the addition of the L-Cys. The OCP increment (ΔOCP) was linear with the concentration of L-Cys within 20 nM to 3 μM. The proposed sensor exhibited lower detection limit of 10 nM L-Cys (S/N = 3), which is significantly lower than those values for other methods reported so far. Other amino acids and glutathione did not affect L-Cys detection. Therefore, this developed approach is sensitive, facile, cost-effective, and environmental-friendly, and could be very promising for the reliable clinically detecting of L-Cys. This work would trigger the interest of developing BFCs based self-powered sensors for practical applications.

  16. Advanced Nanofabrication Process Development for Self-Powered System-on-Chip

    KAUST Repository

    Rojas, Jhonathan Prieto

    2010-11-01

    In this work the development of a Self-Powered System-On-Chip is explored by examining two components of process development in different perspectives. On one side, an energy component is approached from a biochemical standpoint where a Microbial Fuel Cell (MFC) is built with standard microfabrication techniques, displaying a novel electrode based on Carbon Nanotubes (CNTs). The fabrication process involves the formation of a micrometric chamber that hosts an enhanced CNT-based anode. Preliminary results are promising, showing a high current density (113.6mA/m2) compared with other similar cells. Nevertheless many improvements can be done to the main design and further characterization of the anode will give a more complete understanding and bring the device closer to a practical implementation. On a second point of view, nano-patterning through silicon nitride spacer width control is developed, aimed at producing alternative sub-100nm device fabrication with the potential of further scaling thanks to nanowire based structures. These nanostructures are formed from a nano-pattern template, by using a bottom-up fabrication scheme. Uniformity and scalability of the process are demonstrated and its potential described. An estimated area of 0.120μm2 for a 6T-SRAM (Static Random Access Memory) bitcell (6 devices) can be achieved. In summary, by using a novel sustainable energy component and scalable nano-patterning for logic and computing module, this work has successfully collected the essential base knowledge and joined two different elements that synergistically will contribute for the future implementation of a Self-Powered System-on-Chip.

  17. Simultaneous Monitoring of Glucose and Lactate by Self-powered Biosensor

    Directory of Open Access Journals (Sweden)

    Ankit Baingane

    2017-07-01

    Full Text Available A dual self-powered biosensing system integrated with energy amplification circuit is described, for simultaneously monitoring glucose and lactate. The self-powered biosensing system is based on the conventional enzymatic biofuel cell equipped with three 4 mm x 4 mm massively dense mesh network of multi-walled carbon nanotubes (MWCNTs bioelectrodes in parallel configuration. The bioelectrodes employed pyroquinoline quinone glucose dehydrogenase (PQQ-GDH as the biocatalyst for the glucose oxidation and D-Lactate dehydrogenase (D-LDH as the biocatalyst for lactate oxidation. A common laccase modified-MWCNTs bioelectrode served as the cathode for the reduction of molecular oxygen. Two charge pump circuits were coupled with 0.1 mF capacitors functioning as transducers. The advantages of employing capacitors were coupled with the efficient energy amplification of the charge pump circuit to amplify the power output from each of the biofuel and charge/discharge the corresponding capacitor. Under operating conditions, the open circuit voltages and short circuit current densities for 180 mg/dL glucose and 25 mM lactate were 339.2 mV and 228.75 µA/cm2 and 370 mV and 66.17 µA/cm2, respectively. The responses for glucose and lactate were linear up to 630 mg/dL and 30 mM with sensitivities of 20.11 Hz/ mM cm-2 and 9.869 Hz/ mM cm-2, respectively. The potential of the described system was demonstrated to provide stable voltage and current output that was capable of driving the charge pump circuit integrated with the capacitor for simultaneously monitoring glucose and lactate. These results were in good agreement with those previously reported.

  18. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  19. Neutron activation analysis in minerals prospecting

    International Nuclear Information System (INIS)

    Gomez, H.; Duque O, J.

    1988-01-01

    One method multielemental analysis in geological samples has been developed by neutron activation analysis without using standards and by eliminating many of the error sources of the absolute method. It uses the ratio of the activities induced by mass unit, between the element in the sample and one cobalt monitor. The detection limits are good for more than thirty elements in many prospecting programs, with a standard deviation less than 7%. The neutron flux used is 2x10 11 nxcm -2 .S -1 and the HPGE detector has a relative efficiency of 20% and an energy resolution of 1.9 KeV in 1332 KeV photopeak

  20. Monte Carlo estimation of the dose and heating of cobalt adjuster rods irradiated in the CANDU 6 reactor core

    International Nuclear Information System (INIS)

    Gugiu, D.; Dumitrache, I.

    2005-01-01

    The present work is a part of a more complex project related to the replacement of the original stainless steel adjuster rods with cobalt assemblies in the CANDU 6 reactor core. The 60 Co produced by 59 Co irradiation could be used extensively in medicine and industry. The paper will mainly describe some of the reactor physics and safety requirements that must be carried into practice for the Co adjuster rods. The computations related to the neutronic equivalence of the stainless steel adjusters with the Co adjuster assemblies, as well as the estimations of the activity and heating of the irradiated cobalt rods, are performed using the Monte Carlo codes MCNP5 and MONTEBURNS 2.1. The activity values are used to evaluate the dose at the surface of the device designed to transport the cobalt adjusters. (authors)

  1. Nickel and cobalt base alloys

    International Nuclear Information System (INIS)

    Houlle, P.

    1994-01-01

    Nickel base alloys have a good resistance to pitting, cavernous or cracks corrosion. Nevertheless, all the nickel base alloys are not equivalent. Some differences exit between all the families (Ni, Ni-Cu, Ni-Cr-Fe, Ni-Cr-Fe-Mo/W-Cu, Ni-Cr-Mo/W, Ni-Mo). Cobalt base alloys in corrosive conditions are generally used for its wear and cracks resistance, with a compromise to its localised corrosion resistance properties. The choice must be done from the perfect knowledge of the corrosive medium and of the alloys characteristics (chemical, metallurgical). A synthesis of the corrosion resistance in three medium (6% FeCl 3 , 4% NaCl + 1% HCl + 0.1% Fe 2 (SO 4 ) 3 , 11.5% H 2 SO 4 + 1.2% HCl + 1% Fe 2 (SO 4 ) 3 + 1% CuCl 2 ) is presented. (A.B.). 11 refs., 1 fig., 12 tabs

  2. Preparation of high purity cobalt

    International Nuclear Information System (INIS)

    Isshiki, M.; Fukuda, Y.; Igaki, K.

    1985-01-01

    A combination of anion exchange separation, electrolytic extraction, floating zone refining and dry hydrogen treatment was used to purify cobalt. The effectiveness of each purification process was confirmed by measurements of the residual resistivity ratio (RRR) and activation analyses. Proton activation analysis revealed that all the main metallic impurities except iron were effectively removed by a combination of these processes. The effective removal of oxygen, nitrogen and carbon by dry hydrogen treatment was confirmed by activation analyses using 3 He ion beams, proton beams and γ rays. It was found that the rate-controlling step in the decarburization process was a surface reaction. The maximum RRR obtained for the purified specimen was 334, which is higher than previously reported values. (Auth.)

  3. Monitoring of the Irradiated Neutron Fluence in the Neutron Transmutation Doping Process of Hanaro

    Science.gov (United States)

    Kim, Myong-Seop; Park, Sang-Jun

    2009-08-01

    Neutron transmutation doping (NTD) for silicon is a process of the creation of phosphorus impurities in intrinsic or extrinsic silicon by neutron irradiation to obtain silicon semiconductors with extremely uniform dopant distribution. HANARO has two vertical holes for the NTD, and the irradiation for 5 and 6 inch silicon ingots has been going on at one hole. In order to achieve the accurate neutron fluence corresponding to the target resistivity, the real time neutron flux is monitored by self-powered neutron detectors. After irradiation, the total irradiation fluence is confirmed by measuring the absolute activity of activation detectors. In this work, a neutron fluence monitoring method using zirconium foils with the mass of 10 ~ 50 mg was applied to the NTD process of HANARO. We determined the proportional constant of the relationship between the resistivity of the irradiated silicon and the neutron fluence determined by using zirconium foils. The determined constant for the initially n-type silicon was 3.126 × 1019 n·Ω/cm. It was confirmed that the difference between this empirical value and the theoretical one was only 0.5%. Conclusively, the practical methodology to perform the neutron transmutation doping of silicon was established.

  4. Neutron irradiation control in the neutron transmutation doping process in HANARO using SPND

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Gi-Doo; Kim, Myong-Seop [Korea Atomic Energy Research Institute, Yuseong, Daejeon, 305-353, (Korea, Republic of)

    2015-07-01

    The neutron irradiation control method by using self-powered neutron detector (SPND) is developed for the neutron transmutation doping (NTD) application in HANARO. An SPND is installed at a fixed position of the upper part of the sleeve in HANARO NTD hole for real-time monitoring of the neutron irradiation. It is confirmed that the SPND is significantly affected by the in-core condition and surroundings of the facility. Furthermore, the SPND signal changes about 15% throughout a whole cycle according to the change of the control rod position. But, it is also confirmed that the variation of the neutron flux on the silicon ingots inside the irradiation can is not so big while moving of the control rod. Accordingly, the relationship between the ratio of the neutron flux to the SPND signal output and the control rod position is established. In this procedure, the neutron flux measurement by using zirconium foil is utilized. The real NTD irradiation experiments are performed using the established relationship. The irradiated neutron fluence can be controlled within ±1.3% of the target one. The mean value of the irradiation/target ratio of the fluence is 0.9992, and the standard deviation is 0.0071. Thus, it is confirmed that the extremely accurate irradiation would be accomplished. This procedure can be useful for the SPND application installed at the fixed position to the field requiring the extremely high accuracy. (authors)

  5. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  6. Design innovations in neutron and gamma detectors

    International Nuclear Information System (INIS)

    Prasad, K.R.

    2003-01-01

    Neutron and gamma radiation needs to be monitored in most nuclear installations since it is highly penetrating. On-line monitoring of these radiations is very important for the safe and controlled operation of nuclear reactors, accelerators etc. Several design innovations have been carried out on gas ionisation detectors such as boron-lined proportional counters and ion chambers, fission detectors, gamma ion chambers as well as self-powered detectors. The use of additional structures within boron-lined detectors has enhanced their neutron sensitivity without a corresponding increase in the unwanted gamma sensitivity. The neutron sensitivity of fission counters can be enhanced by designing them as transmission line devices. Ion chambers with two and six pairs of electrodes have been developed for monitoring pulsed x-ray background at accelerator areas. Ion chambers have been employed at gamma fields up to 80 kR/h by deriving the exposure levels on-line using microcontroller devices programmed on the basis of theoretical and empirical formulas. The use of gas electron multiplier foils is proposed for charge multiplication in ion chambers. Self-powered detectors with new emitter materials like Hi, Ni and Inconel have been developed. (author)

  7. Cobalt-60 control in Ontario Hydro reactors

    International Nuclear Information System (INIS)

    Lacy, C.S.

    1988-01-01

    This paper discusses the impact of specifying reduced Cobalt-59 in the primary heat transport circuit materials of construction on the radiation fields developed around the primary circuit. An eight-fold reduction in steam generator radiation fields due to Cobalt-60 has been observed for two identical sets of reactors, one with and one without Cobalt-59 control. The comparison is between eight reactors at the Pickering Nuclear Generating Station (PNGS). Units 5 to 8 (PNGS-B) are identical to Units 1 to 4 (PNGS-A) except that PNGS-B has reduced impurity Cobalt-59 in the alloys of construction and a reduced use of stellite. The effects of chemistry control are also discussed

  8. Nano cobalt oxides for photocatalytic hydrogen production

    KAUST Repository

    Mangrulkar, Priti A.; Joshi, Meenal M.; Tijare, Saumitra N.; Polshettiwar, Vivek; Labhsetwar, Nitin K.; Rayalu, Sadhana Suresh

    2012-01-01

    of various operating parameters in hydrogen generation by nano cobalt oxide was then studied in detail. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  9. An elevator for cobalt-60 source

    International Nuclear Information System (INIS)

    Tang Zaimin; Liang Donghu

    1990-07-01

    The elevator used for cobalt-60 source is a key device in the irradiation industry. It plays an important role in the safety and control of irradiation operation as well as the utilization rate of radiation source. From 1983 to 1986, Beijing Institute of Nuclear Engineering undertook designing of various size irradiation projects for different uses. Since then a kind of cobalt-60 source elevator suited for the irradiator of wet-source-storage has been chosen. It is reliable in the operation and complete in the function. An automatic control circuit brings the systems of cobalt-60 source elevator into an interlock system which ensures the irradiation operation safety. Besides introducing the structural features and performance of this elevator, the conditions of safety interlocking in raising or lowering the cobalt-60 source is also discussed. The discussion is from the safety viewpoint of operating an irradiator and irradiation technology

  10. A high-speed data acquisition system to measure low-level current from self-powered flux detectors in CANDU nuclear reactors

    International Nuclear Information System (INIS)

    Lawrence, C.B.; Hall, D.S.

    1982-05-01

    Self-powered flux detectors are used in CANDU nuclear power reactors to determine the spatial neutron flux distribution in the reactor core for use by both the reactor control and safety systems. To establish the dynamic response of different types of flux detectors, the Chalk River Nuclear Laboratories have an ongoing experimental irradiation program in the NRU research reactor for which a data acquistion system has been developed. The system described in this paper is used to measure the currents from the detectors both at a slow, regular logging interval, and at a rapid, adaptive rate following a reactor shutdown. Currents that range from 100 pA to 1 mA full scale can be measured from up to 38 detectors and stored at sampling rates of up to 20 samples per second. The dynamic characteristics of the detectors can be computed from the stored records. The data acquisition system comprises a DEC LSI-11/23 microcomputer, dual cartridge disks, floppy disks, a hard copy and a video display terminal. The RT-11 operating system is used and all application programs are written in FORTRAN

  11. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  12. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  13. Transport properties of cobalt at low temperatures

    DEFF Research Database (Denmark)

    Radharkishna, P.; Nielsen, Mourits

    1965-01-01

    Measurements are made of electrical resistivity, absolute thermoelectric power, and thermal conductivity of polycrystalline cobalt between 1.2 and 6 K; results are discussed on basis of inter-electronic scattering.......Measurements are made of electrical resistivity, absolute thermoelectric power, and thermal conductivity of polycrystalline cobalt between 1.2 and 6 K; results are discussed on basis of inter-electronic scattering....

  14. COBALT COMPOUNDS AS ANTIDOTES FOR HYDROCYANIC ACID.

    Science.gov (United States)

    EVANS, C L

    1964-12-01

    The antidotal potency of a cobalt salt (acetate), of dicobalt edetate, of hydroxocobalamin and of cobinamide against hydrocyanic acid was examined mainly on mice and rabbits. All the compounds were active antidotes for up to twice the LD50; under some conditions for larger doses. The most successful was cobalt acetate for rabbits (5xLD50), which was effective at a molar cyanide/cobalt (CN/Co) ratio of 5, but had as a side-effect intense purgation. Hydroxocobalamin was irregular in action, but on the whole was most effective for mice (4.5xLD50 at a molar ratio of 1), and had no apparent side effects. Dicobalt edetate, at molar ratios of up to 2, was more effective for rabbits (3xLD50) than for mice (2xLD50), but had fewer side effects than cobalt acetate. The effect of thiosulphate was to augment the efficacy of dicobalt edetate and, in mice, that of hydroxocobalamin; but, apparently, in rabbits, to reduce that of hydroxocobalamin. Cobinamide, at a molar ratio of 1, was slightly more effective than hydroxocobalamin on rabbits and also less irregular in its action. Cobalt acetate by mouth was effective against orally administered hydrocyanic acid. The oxygen uptake of the body, reduced by cyanide, is rapidly reinstated when one of the cobalt antidotes has been successfully administered.

  15. A photovoltaic self-powered gas sensor based on a single-walled carbon nanotube/Si heterojunction.

    Science.gov (United States)

    Liu, L; Li, G H; Wang, Y; Wang, Y Y; Li, T; Zhang, T; Qin, S J

    2017-12-07

    We present a novel photovoltaic self-powered gas sensor based on a p-type single-walled carbon nanotube (SWNT) and n-type silicon (n-Si) heterojunction. The energy from visible light suffices to drive the device owing to a built-in electric field (BEF) induced by the differences between the Fermi levels of SWNTs and n-Si.

  16. A smart mobile pouch as a biomechanical energy harvester towards self-powered smart wireless power transfer applications.

    Science.gov (United States)

    Chandrasekhar, Arunkumar; Alluri, Nagamalleswara Rao; Sudhakaran, M S P; Mok, Young Sun; Kim, Sang-Jae

    2017-07-20

    A Smart Mobile Pouch Triboelectric Nanogenerator (SMP-TENG) is introduced as a promising eco-friendly approach for scavenging biomechanical energy for powering next generation intelligent devices and smart phones. This is a cost-effective and robust method for harvesting energy from human motion, by utilizing worn fabrics as a contact material. The SMP-TENG is capable of harvesting energy in two operational modes: lateral sliding and vertical contact and separation. Moreover, the SMP-TENG can also act as a self-powered emergency flashlight and self-powered pedometer during normal human motion. A wireless power transmission setup integrated with SMP-TENG is demonstrated. This upgrades the traditional energy harvesting device into a self-powered wireless power transfer SMP-TENG. The wirelessly transferred power can be used to charge a Li-ion battery and light LEDs. The SMP-TENG opens a wide range of opportunities in the field of self-powered devices and low maintenance energy harvesting systems for portable and wearable electronic gadgets.

  17. Flexible Self-Powered GaN Ultraviolet Photoswitch with Piezo-Phototronic Effect Enhanced On/Off Ratio.

    Science.gov (United States)

    Peng, Mingzeng; Liu, Yudong; Yu, Aifang; Zhang, Yang; Liu, Caihong; Liu, Jingyu; Wu, Wei; Zhang, Ke; Shi, Xieqing; Kou, Jinzong; Zhai, Junyi; Wang, Zhong Lin

    2016-01-26

    Flexible self-powered sensing is urgently needed for wearable, portable, sustainable, maintenance-free and long-term applications. Here, we developed a flexible and self-powered GaN membrane-based ultraviolet (UV) photoswitch with high on/off ratio and excellent sensitivity. Even without any power supply, the driving force of UV photogenerated carriers can be well boosted by the combination of both built-in electric field and piezoelectric polarization field. The asymmetric metal-semiconductor-metal structure has been elaborately utilized to enhance the carrier separation and transport for highly sensitive UV photoresponse. Its UV on/off ratio and detection sensitivity reach to 4.67 × 10(5) and 1.78 × 10(12) cm·Hz(0.5) W(1-), respectively. Due to its excellent mechanical flexibility, the piezoelectric polarization field in GaN membrane can be easily tuned/controlled based on piezo-phototronic effect. Under 1% strain, a stronger and broader depletion region can be obtained to further enhance UV on/off ratio up to 154%. As a result, our research can not only provide a deep understanding of local electric field effects on self-powered optoelectronic detection, but also promote the development of self-powered flexible optoelectronic devices and integrated systems.

  18. Enhanced Performance of a Self-Powered Organic/Inorganic Photodetector by Pyro-Phototronic and Piezo-Phototronic Effects.

    Science.gov (United States)

    Peng, Wenbo; Wang, Xingfu; Yu, Ruomeng; Dai, Yejing; Zou, Haiyang; Wang, Aurelia C; He, Yongning; Wang, Zhong Lin

    2017-06-01

    Self-powered photodetectors (PDs) have long been realized by utilizing photovoltaic effect and their performances can be effectively enhanced by introducing the piezo-phototronic effect. Recently, a novel pyro-phototronic effect is invented as an alternative approach for performance enhancement of self-powered PDs. Here, a self-powered organic/inorganic PD is demonstrated and the influences of externally applied strain on the pyro-phototronic and the photovoltaic effects are thoroughly investigated. Under 325 nm 2.30 mW cm -2 UV illumination and at a -0.45% compressive strain, the PD's photocurrent is dramatically enhanced from ≈14.5 to ≈103 nA by combining the pyro-phototronic and piezo-phototronic effects together, showing a significant improvement of over 600%. Theoretical simulations have been carried out via the finite element method to propose the underlying working mechanism. Moreover, the pyro-phototronic effect can be introduced by applying a -0.45% compressive strain to greatly enhance the PD's response to 442 nm illumination, including photocurrent, rise time, and fall time. This work provides in-depth understandings about the pyro-phototronic and the piezo-phototronic effects on the performances of self-powered PD to light sources with different wavelengths and indicates huge potential of these two effects in optoelectronic devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  20. Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Jellesen, Morten S; Menné, Torkil

    2010-01-01

    Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure.......Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure....

  1. Synthesis of new cobalt aluminophosphate framework by opening a cobalt methylphosphonate layered material

    Czech Academy of Sciences Publication Activity Database

    Zaarour, M.; Pérez, O.; Boullay, P.; Martens, J.; Mihailova, B.; Karaghiosoff, K.; Palatinus, Lukáš; Mintova, S.

    2017-01-01

    Roč. 19, č. 34 (2017), s. 5100-5105 ISSN 1466-8033 Institutional support: RVO:68378271 Keywords : cobalt aluminophosphate * cobalt methylphosphonate * layered materials * crystallic structure * X-ray diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.474, year: 2016

  2. AN ELECTROPLATING METHOD OF FORMING PLATINGS OF NICKEL, COBALT, NICKEL ALLOYS OR COBALT ALLOYS

    DEFF Research Database (Denmark)

    1997-01-01

    An electroplating method of forming platings of nickel, cobalt, nickel alloys or cobalt alloys with reduced stresses in an electrodepositing bath of the type: Watt's bath, chloride bath or a combination thereof, by employing pulse plating with periodic reverse pulse and a sulfonated naphthalene...

  3. Performance Test for Neutron Detector and Associated System using Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seongwoo; Park, Sung Jae; Cho, Man Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Oh, Se Hyun [USERS, Daejeon (Korea, Republic of); Shin, Ho Cheol [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    SPND (Self-Powered Neutron Detector) has been developed to extend its lifespan. ENFMS (Ex-Core Flux Monitoring System) of pressurized water reactor has been also improved. After the development and improvement, their performance must be verified under the neutron irradiation environment. We used a research reactor for the performance verification of neutron detector and associated system because the research reactor can meet the neutron flux level of commercial nuclear reactor. In this paper, we report the performance verification method and result for the SPND and ENFMS using the research reactor. The performance tests for the SPND and ENFMS were conducted using UCI TRIGA reactor. The test environment of commercial reactor’s neutron flux level must be required. However, it is difficult to perform the test in the commercial rector due to the constraint of time and space. The research reactor can be good alternative neutron source for the test of neutron detectors and associated system.

  4. Online In-Core Thermal Neutron Flux Measurement for the Validation of Computational Methods

    International Nuclear Information System (INIS)

    Mohamad Hairie Rabir; Muhammad Rawi Mohamed Zin; Yahya Ismail

    2016-01-01

    In order to verify and validate the computational methods for neutron flux calculation in RTP calculations, a series of thermal neutron flux measurement has been performed. The Self Powered Neutron Detector (SPND) was used to measure thermal neutron flux to verify the calculated neutron flux distribution in the TRIGA reactor. Measurements results obtained online for different power level of the reactor. The experimental results were compared to the calculations performed with Monte Carlo code MCNP using detailed geometrical model of the reactor. The calculated and measured thermal neutron flux in the core are in very good agreement indicating that the material and geometrical properties of the reactor core are modelled well. In conclusion one can state that our computational model describes very well the neutron flux distribution in the reactor core. Since the computational model properly describes the reactor core it can be used for calculations of reactor core parameters and for optimization of RTP utilization. (author)

  5. Control of carbon nanotube growth using cobalt nanoparticles as catalyst

    International Nuclear Information System (INIS)

    Huh, Yoon; Green, Malcolm L.H.; Kim, Young Heon; Lee, Jeong Yong; Lee, Cheol Jin

    2005-01-01

    We have controllably grown carbon nanotubes using uniformly distributed cobalt nanoparticles as catalyst. Cobalt nanoparticles with a uniform size were synthesized by chemical reaction and colloidal solutions including the cobalt nanoparticles were prepared. The cobalt nanoparticles were uniformly distributed on silicon substrates by a spin-coating method. Carbon nanotubes with a uniform diameter were synthesized on the cobalt nanoparticles by thermal chemical vapor deposition of acetylene gas. The density and vertical alignment of carbon nanotubes could be controlled by adjusting the density of cobalt (Co) nanoparticles

  6. Inhibition of charge recombination for enhanced dye-sensitized solar cells and self-powered UV sensors by surface modification

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Liang, E-mail: chuliang@njupt.edu.cn [Advanced Energy Technology Center, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Wuhan National Laboratory for Optoelectronics (WNLO)-School of Physics, Huazhong University of Science and Technology (HUST), Wuhan 430074 (China); Qin, Zhengfei; Liu, Wei [School of Materials Science and Engineering (SMSE), Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Ma, Xin’guo, E-mail: maxg2013@sohu.com [Hubei Collaborative Innovation Center for High-efficiency Utilization of Solar Energy, Hubei University of Technology, Wuhan 430068 (China)

    2016-12-15

    Graphical abstract: Inhibition of charge recombination was utilized to prolong electrode lifetime in dye-sensitized solar cells (DSSCs) and self-powered UV sensors based on TiO{sub 2}-modified SnO{sub 2} photoelectrodes. The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the electron lifetime was significantly prolonged in DSSCs after TiO{sub 2} modification. And in self-powered UV sensors, the sensitivity and response time were enhanced. - Highlights: • The surface modification to inhibit charge recombination was utilized in photovoltaic devices. • Inhibition of charge recombination can prolong electrode lifetime in photovoltaic devices. • Enhanced DSSCs and self-powered UV sensors based on SnO{sub 2} photoelectrodes were obtained by TiO{sub 2} modification. - Abstract: The surface modification to inhibit charge recombination was utilized in dye-sensitized solar cells (DSSCs) and self-powered ultraviolet (UV) sensors based on SnO{sub 2} hierarchical microspheres by TiO{sub 2} modification. For DSSCs with SnO{sub 2} photoelectrodes modified by TiO{sub 2}, the power conversion efficiency (PCE) was improved from 1.40% to 4.15% under standard AM 1.5G illumination (100 mW/cm{sup 2}). The electrochemical impedance spectroscopy and open-circuit voltage decay measurements indicated that the charge recombination was effectively inhibited, resulting in long electron lifetime. For UV sensors with SnO{sub 2} photoelectrodes modified by TiO{sub 2} layer, the self-powered property was more obvious, and the sensitivity and response time were enhanced from 91 to 6229 and 0.15 s to 0.055 s, respectively. The surface modification can engineer the interface energy to inhibit charge recombination, which is a desirable approach to improve the performance of photoelectric nanodevice.

  7. The neutron

    International Nuclear Information System (INIS)

    Kredov, B.M.

    1979-01-01

    The history of the neutron is displayed on the basis of contributions by scientists who produced outstanding results in neutron research (part 1), of summarizing discoveries and theories which led to the discovery of the neutron and the resulting development of nuclear physics (part 2), and of fundamental papers written by Rutherford, Chadwick, Iwanenko, and others (appendix). Of interest to physicists, historians, and students

  8. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  9. Cobalt as a gastric juice volume marker: Comparison of two methods of estimation

    International Nuclear Information System (INIS)

    Gana, T.J.; MacPherson, B.R.; Ng, D.; Koo, J.

    1990-01-01

    We investigated the use of cobalt-EDTA, a novel, nonabsorbable liquid phase marker, in the estimation of secretory volumes during topical misoprostol (synthetic PGE, analog) administration in the canine chambered gastric segment. We compared atomic absorption spectrophotometry (AAS) and instrumental neutron activation analysis (INAA) in the estimation of [Co]. Mucosal bathing solutions containing cobalt-EDTA were instilled into and recovered from the chamber by gravity every 15-min period as follows: (i) basal--60 min; (ii) misoprostol periods--150 min (plus 0.1-, 1-, 10-, 100-, and 1000-micrograms doses of misoprostol for two periods per dose). The recovered solutions were analyzed for [Co] by AAS and INAA. Total cobalt recovery by AAS after chamber washout was 102.97 +/- 0.98%. Mean +/- SE volumes (12.14 +/- 0.33 and 13.24 +/- 0.60 ml/15 min) obtained respectively from AAS and INAA were significantly higher (P less than 0.001) than the recovered mean volumes (10.51 +/- 0.17 ml/15 min). The percentage error in volume collection increased (range: 9.3-52.7%) with the volume of secretion. Values of [Co] obtained by the two techniques were comparable and not significantly different from each other (P greater than 0.05). INAA-estimated mean +/- SE [Co] showed consistently higher coefficients of variation. Spectra obtained for all samples during INAA measurements showed significant Compton background activity from 24Na and 38Cl. Cobalt-EDTA did not grossly or histologically damage the gastric mucosa. We conclude that cobalt is not adsorbed, absorbed, or metabolized, and is a suitable and reliable volume marker in this model

  10. Cobalt-60 Machines and Medical Linear Accelerators: Competing Technologies for External Beam Radiotherapy.

    Science.gov (United States)

    Healy, B J; van der Merwe, D; Christaki, K E; Meghzifene, A

    2017-02-01

    Medical linear accelerators (linacs) and cobalt-60 machines are both mature technologies for external beam radiotherapy. A comparison is made between these two technologies in terms of infrastructure and maintenance, dosimetry, shielding requirements, staffing, costs, security, patient throughput and clinical use. Infrastructure and maintenance are more demanding for linacs due to the complex electric componentry. In dosimetry, a higher beam energy, modulated dose rate and smaller focal spot size mean that it is easier to create an optimised treatment with a linac for conformal dose coverage of the tumour while sparing healthy organs at risk. In shielding, the requirements for a concrete bunker are similar for cobalt-60 machines and linacs but extra shielding and protection from neutrons are required for linacs. Staffing levels can be higher for linacs and more staff training is required for linacs. Life cycle costs are higher for linacs, especially multi-energy linacs. Security is more complex for cobalt-60 machines because of the high activity radioactive source. Patient throughput can be affected by source decay for cobalt-60 machines but poor maintenance and breakdowns can severely affect patient throughput for linacs. In clinical use, more complex treatment techniques are easier to achieve with linacs, and the availability of electron beams on high-energy linacs can be useful for certain treatments. In summary, there is no simple answer to the question of the choice of either cobalt-60 machines or linacs for radiotherapy in low- and middle-income countries. In fact a radiotherapy department with a combination of technologies, including orthovoltage X-ray units, may be an option. Local needs, conditions and resources will have to be factored into any decision on technology taking into account the characteristics of both forms of teletherapy, with the primary goal being the sustainability of the radiotherapy service over the useful lifetime of the equipment

  11. Calcium-assisted reduction of cobalt ferrite nanoparticles for nanostructured iron cobalt with enhanced magnetic performance

    International Nuclear Information System (INIS)

    Qi, B.; Andrew, J. S.; Arnold, D. P.

    2017-01-01

    This paper demonstrates the potential of a calcium-assisted reduction process for synthesizing fine-grain (~100 nm) metal alloys from metal oxide nanoparticles. To demonstrate the process, an iron cobalt alloy (Fe_6_6Co_3_4) is obtained by hydrogen annealing 7-nm cobalt ferrite (CoFe_2O_4) nanoparticles in the presence of calcium granules. The calcium serves as a strong reducing agent, promoting the phase transition from cobalt ferrite to a metallic iron cobalt alloy, while maintaining high crystallinity. Magnetic measurements demonstrate the annealing temperature is the dominant factor of tuning the grain size and magnetic properties. Annealing at 700 °C for 1 h maximizes the magnetic saturation, up to 2.4 T (235 emu/g), which matches that of bulk iron cobalt.

  12. Calcium-assisted reduction of cobalt ferrite nanoparticles for nanostructured iron cobalt with enhanced magnetic performance

    Energy Technology Data Exchange (ETDEWEB)

    Qi, B. [University of Florida, Interdisciplinary Microsystems Group, Department of Electrical and Computer Engineering (United States); Andrew, J. S. [University of Florida, Department of Materials Science and Engineering (United States); Arnold, D. P., E-mail: darnold@ufl.edu [University of Florida, Interdisciplinary Microsystems Group, Department of Electrical and Computer Engineering (United States)

    2017-03-15

    This paper demonstrates the potential of a calcium-assisted reduction process for synthesizing fine-grain (~100 nm) metal alloys from metal oxide nanoparticles. To demonstrate the process, an iron cobalt alloy (Fe{sub 66}Co{sub 34}) is obtained by hydrogen annealing 7-nm cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles in the presence of calcium granules. The calcium serves as a strong reducing agent, promoting the phase transition from cobalt ferrite to a metallic iron cobalt alloy, while maintaining high crystallinity. Magnetic measurements demonstrate the annealing temperature is the dominant factor of tuning the grain size and magnetic properties. Annealing at 700 °C for 1 h maximizes the magnetic saturation, up to 2.4 T (235 emu/g), which matches that of bulk iron cobalt.

  13. Characteristics of Fabricated SiC Neutron Detectors for Neutron Flux Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Soo; Ha, Jang Ho; Park, Se Hwan; Lee, Kyu Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Cheol Ho [Hanyang University, Seoul (Korea, Republic of)

    2011-05-15

    An SPND (Self-powered Neutron Detector) is commonly used for neutron detection in NPP (Nuclear Power Plant) by virtue of un-reactivity for gamma-rays. But it has a drawback, which is that it cannot detect neutrons in real time due to beta emissions (about > 48 s) after reactions between neutrons and {sup 103}Rh in an SPND. And Generation IV reactors such as MSR (Molten-salt reactor), SFR (Sodium-cooled fast reactor), and GFR (Gas-cooled fast reactor) are designed to compact size and integration type. For GEN IV reactor, neutron monitor also must be compact-sized to apply such reactor easily and much more reliable. The wide band-gap semiconductors such as SiC, AlN, and diamond make them an attractive alternative in applications in harsh environments by virtue of the lower operating voltage, faster charge-collection times compared with gas-filled detectors, and compact size.1) In this study, two PIN-type SiC semiconductor neutron detectors, which are for fast neutron detection by elastic and inelastic scattering SiC atoms and for thermal neutron detection by charged particle emissions of 6LiF reaction, were designed and fabricated for NPP-related applications. Preliminary tests such as I-V and alpha response were performed and neutron responses at ENF in HANARO research reactor were also addressed. The application feasibility of the fabricated SiC neutron detector as an in-core neutron monitor was discussed

  14. Simulation and testing of a micro electromagnetic energy harvester for self-powered system

    Directory of Open Access Journals (Sweden)

    Yiming Lei

    2014-01-01

    Full Text Available This paper describes a low cost and efficient electromagnetic vibration energy harvester (EVEH for a self-powered system. The EVEH consists of a resistant (copper spring, a permanent magnet (NdFeB35 and a wire-wound copper coil. The copper spring was fabricated by the laser precision cutting technology. A numerical model was adopted to analyze magnetic field distribution of a rectangle permanent magnet. The finite element (FEM soft ANSYS was used to simulate the mechanical properties of the system. The testing results show that the micro electromagnetic vibration energy harvester can generate the maximal power 205.38 μW at a resonance frequency of 124.2 Hz with an acceleration of 0.5 g (g = 9.8 ms−2 across a load the 265 Ω and a superior normalized power density (NPD of 456.5 μW cm−3 g−2. The magnetic field distribution of the permanent magnet was calculated to optimize geometric parameters of the coil. The proposed EVEH has a high efficiency with the lower cost.

  15. Photovoltaic-Pyroelectric Coupled Effect Induced Electricity for Self-Powered Photodetector System.

    Science.gov (United States)

    Ma, Nan; Zhang, Kewei; Yang, Ya

    2017-12-01

    Ferroelectric materials have demonstrated novel photovoltaic effect to scavenge solar energy. However, most of the ferroelectric materials with wide bandgaps (2.7-4 eV) suffer from low power conversion efficiency of less than 0.5% due to absorbing only 8-20% of solar spectrum. Instead of harvesting solar energy, these ferroelectric materials can be well suited for photodetector applications, especially for sensing near-UV irradiations. Here, a ferroelectric BaTiO 3 film-based photodetector is demonstrated that can be operated without using any external power source and a fast sensing of 405 nm light illumination is enabled. As compared with photovoltaic effect, both the responsivity and the specific detectivity of the photodetector can be dramatically enhanced by larger than 260% due to the light-induced photovoltaic-pyroelectric coupled effect. A self-powered photodetector array system can be utilized to achieve spatially resolved light intensity detection by recording the output voltage signals as a mapping figure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Self-Powered Active Sensor with Concentric Topography of Piezoelectric Fibers.

    Science.gov (United States)

    Fuh, Yiin Kuen; Huang, Zih Ming; Wang, Bo Sheng; Li, Shan Chien

    2017-12-01

    In this study, we demonstrated a flexible and self-powered sensor based on piezoelectric fibers in the diameter range of nano- and micro-scales. Our work is distinctively different from previous electrospinning research; we fabricated this apparatus precisely via near-field electrospinning which has a spectacular performance to harvest mechanical deformation in arbitrary direction and a novel concentrically circular topography. There are many piezoelectric devices based on electrospinning polymeric fibers. However, the fibers were mostly patterned in parallel lines and they could be actuated in limited direction only. To overcome this predicament, we re-arranged the parallel alignment into concentric circle pattern which made it possible to collect the mechanical energy whenever the deformation is along same axis or not. Despite the change of topography, the output voltage and current could still reach to 5 V and 400 nA, respectively, despite the mechanical deformation was from different direction. This new arbitrarily directional piezoelectric generator with concentrically circular topography (PGCT) allowed the piezoelectric device to harvest more mechanical energy than the one-directional alignment fiber-based devices, and this PGCT could perform even better output which promised more versatile and efficient using as a wearable electronics or sensor.

  17. Zinc Oxide-Based Self-Powered Potentiometric Chemical Sensors for Biomolecules and Metal Ions.

    Science.gov (United States)

    Israr-Qadir, Muhammad; Jamil-Rana, Sadaf; Nur, Omer; Willander, Magnus

    2017-07-19

    Advances in the miniaturization and portability of the chemical sensing devices have always been hindered by the external power supply problem, which has focused new interest in the fabrication of self-powered sensing devices for disease diagnosis and the monitoring of analytes. This review describes the fabrication of ZnO nanomaterial-based sensors synthesized on different conducting substrates for extracellular detection, and the use of a sharp borosilicate glass capillary (diameter, d = 700 nm) to grow ZnO nanostructures for intracellular detection purposes in individual human and frog cells. The electrocatalytic activity and fast electron transfer properties of the ZnO materials provide the necessary energy to operate as well as a quick sensing device output response, where the role of the nanomorphology utilized for the fabrication of the sensor is crucial for the production of the operational energy. Simplicity, design, cost, sensitivity, selectivity and a quick and stable response are the most important features of a reliable sensor for routine applications. The review details the extra- and intra-cellular applications of the biosensors for the detection and monitoring of different metallic ions present in biological matrices, along with the biomolecules glucose and cholesterol.

  18. Self-Powered Safety Helmet Based on Hybridized Nanogenerator for Emergency.

    Science.gov (United States)

    Jin, Long; Chen, Jun; Zhang, Binbin; Deng, Weili; Zhang, Lei; Zhang, Haitao; Huang, Xi; Zhu, Minhao; Yang, Weiqing; Wang, Zhong Lin

    2016-08-23

    The rapid development of Internet of Things and the related sensor technology requires sustainable power sources for their continuous operation. Scavenging and utilizing the ambient environmental energy could be a superior solution. Here, we report a self-powered helmet for emergency, which was powered by the energy converted from ambient mechanical vibration via a hybridized nanogenerator that consists of a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG). Integrating with transformers and rectifiers, the hybridized nanogenerator can deliver a power density up to 167.22 W/m(3), which was demonstrated to light up 1000 commercial light-emitting diodes (LEDs) instantaneously. By wearing the developed safety helmet, equipped with rationally designed hybridized nanogenerator, the harvested vibration energy from natural human motion is also capable of powering a wireless pedometer for real-time transmitting data reporting to a personal cell phone. Without adding much extra weight to a commercial one, the developed wearing helmet can be a superior sustainable power source for explorers, engineers, mine-workers under well, as well as and disaster-relief workers, especially in remote areas. This work not only presents a significant step toward energy harvesting from human biomechanical movement, but also greatly expands the applicability of TENGs as power sources for self-sustained electronics.

  19. A high-efficiency self-powered wireless sensor node for monitoring concerning vibratory events

    Science.gov (United States)

    Xu, Dacheng; Li, Suiqiong; Li, Mengyang; Xie, Danpeng; Dong, Chuan; Li, Xinxin

    2017-09-01

    This paper presents a self-powered wireless alarming sensor node (SWASN), which was designed to monitor the occurrence of concerning vibratory events. The major components of the sensor node include a vibration-threshold-triggered energy harvester (VTTEH) that powers the sensor node, a dual threshold voltage control circuit (DTVCC) for power management and a radio frequency (RF) signal transmitting module. The VTTEH generates significant electric energy only when the input vibration reaches certain amplitude. Thus, the VTTEH serves as both the power source and the vibration-event-sensing element for the sensor node. The DTVCC was specifically designed to utilize the limited power supply from the VTTEH to operate the sensor node. Constructed with only voltage detectors and MOSFETs, the DTVCC achieved low power consumption, which was 65% lower compared with the power management circuit designed in our previous work. Meanwhile, a RF transmit circuit was constructed based on the commercially available CC1110-F32 wireless transceiver chip and a compact planar antenna was designed to improve the signal transmission distance. The sensor node was fabricated and was characterized both in the laboratory and in the field. Experimental results showed that the SWASN could automatically send out alarming signals when the simulated concerning event occurred. The waiting time between two consecutive transmission periods is less than 125 s and the transmission distance can reach 1.31 km. The SWASN will have broad applications in field surveillances.

  20. A Self-Powered Hybrid Energy Scavenging System Utilizing RF and Vibration Based Electromagnetic Harvesters

    International Nuclear Information System (INIS)

    Uluşan, H; Gharehbaghi, K; Külah, H; Zorlu, Ö; Muhtaroğlu, A

    2015-01-01

    This study presents a novel hybrid system that combines the power generated simultaneously by a vibration-based Electromagnetic (EM) harvester and a UHF band RF harvester. The novel hybrid scavenger interface uses a power management circuit in 180 nm CMOS technology to step-up and to regulate the combined output. At the first stage of the system, the RF harvester generates positive DC output with a 7-stage threshold compensated rectifier, while the EM harvester generates negative DC output with a self-powered AC/DC negative doubler circuit. At the second stage, the generated voltages are serially added, stepped-up with an on-chip charge pump circuit, and regulated to a typical battery voltage of 3 V. Test results indicate that the hybrid operation enables generation of 9 μW at 3 V output for a wide range of input stimulations, which could not be attained with either harvesting mode by itself. Moreover the hybrid system behaves as a typical battery, and keeps the output voltage stable at 3 V up to 18 μW of output power. The presented system is the first battery-like harvester to our knowledge that generates energy from two independent sources and regulates the output to a stable DC voltage. (paper)

  1. Highly Selective and Sensitive Self-Powered Glucose Sensor Based on Capacitor Circuit.

    Science.gov (United States)

    Slaughter, Gymama; Kulkarni, Tanmay

    2017-05-03

    Enzymatic glucose biosensors are being developed to incorporate nanoscale materials with the biological recognition elements to assist in the rapid and sensitive detection of glucose. Here we present a highly sensitive and selective glucose sensor based on capacitor circuit that is capable of selectively sensing glucose while simultaneously powering a small microelectronic device. Multi-walled carbon nanotubes (MWCNTs) is chemically modified with pyrroloquinoline quinone glucose dehydrogenase (PQQ-GDH) and bilirubin oxidase (BOD) at anode and cathode, respectively, in the biofuel cell arrangement. The input voltage (as low as 0.25 V) from the biofuel cell is converted to a stepped-up power and charged to the capacitor to the voltage of 1.8 V. The frequency of the charge/discharge cycle of the capacitor corresponded to the oxidation of glucose. The biofuel cell structure-based glucose sensor synergizes the advantages of both the glucose biosensor and biofuel cell. In addition, this glucose sensor favored a very high selectivity towards glucose in the presence of competing and non-competing analytes. It exhibited unprecedented sensitivity of 37.66 Hz/mM.cm 2 and a linear range of 1 to 20 mM. This innovative self-powered glucose sensor opens new doors for implementation of biofuel cells and capacitor circuits for medical diagnosis and powering therapeutic devices.

  2. Use of self-powered detectors of near containment gamma monitoring

    International Nuclear Information System (INIS)

    Kemp, J.; LaFontaine, M.; Sharma, H.

    2001-01-01

    A study was conducted during the period April to May 1988, to select a self-powered detector (SPD) with an appropriate emitter for measuring the gamma radiation dose rate in near-containment. The selected SPD would be used in the containment monitoring systems for the Ringhals and Forsmark reactors in Sweden. In-containment gamma radiation (81 keV to ∼3 MeV energy range) could result from the release of gaseous fission-product nuclides of bromine, krypton, iodine and xenon. Associated dose rates can range from 10 to 10 6 Gy/h. Tests were performed on platinum and vanadium emitter SPDs 1 using 60 Co, 192 Ir and X-ray gamma/photon sources. A gamma energy dependent polarity change in the signal from the Pt SPD (signal goes from positive to negative as energy drops below 100 keV), coupled with a non-linear response, eliminated that design from further study in this application. The vanadium SPDs produced a linear, negative signal irrespective of the impingent gamma energy level. The gamma sensitivity of the 18 V SPDs tested in the program, ranged from -1.07 x 10 -14 A/Gy/h to -1.87 x 10 -14 A/Gy/h per metre emitter length. (author)

  3. Energy Harvesting from the Animal/Human Body for Self-Powered Electronics.

    Science.gov (United States)

    Dagdeviren, Canan; Li, Zhou; Wang, Zhong Lin

    2017-06-21

    Living subjects (i.e., humans and animals) have abundant sources of energy in chemical, thermal, and mechanical forms. The use of these energies presents a viable way to overcome the battery capacity limitation that constrains the long-term operation of wearable/implantable devices. The intersection of novel materials and fabrication techniques offers boundless possibilities for the benefit of human health and well-being via various types of energy harvesters. This review summarizes the existing approaches that have been demonstrated to harvest energy from the bodies of living subjects for self-powered electronics. We present material choices, device layouts, and operation principles of these energy harvesters with a focus on in vivo applications. We discuss a broad range of energy harvesters placed in or on various body parts of human and animal models. We conclude with an outlook of future research in which the integration of various energy harvesters with advanced electronics can provide a new platform for the development of novel technologies for disease diagnostics, treatment, and prevention.

  4. Medlay: A Reconfigurable Micro-Power Management to Investigate Self-Powered Systems

    Directory of Open Access Journals (Sweden)

    Jan Kokert

    2018-01-01

    Full Text Available In self-powered microsystems, a power management is essential to extract, transfer and regulate power from energy harvesting sources to loads such as sensors. The challenge is to consider all of the different structures and components available and build the optimal power management on a microscale. The purpose of this paper is to streamline the design process by creating a novel reconfigurable testbed called Medlay. First, we propose a uniform interface for management functions e.g., power conversion, energy storing and power routing. This interface results in a clear layout because power and status pins are strictly separated, and inputs and outputs have fixed positions. Medlay is the ready-to-use and open-hardware platform based on the interface. It consists of a base board and small modules incorporating e.g., dc-dc converters, power switches and supercapacitors. Measurements confirm that Medlay represents a system on one circuit board, as parasitic effects of the interconnections are negligible. The versatility regarding different setups on the testbed is determined to over 250,000 combinations by layout graph grammar. Lastly, we underline the applicability by recreating three state-of-the-art systems with the testbed. In conclusion, Medlay facilitates building and testing power management in a very compact, clear and extensible fashion.

  5. High-performance piezoelectric nanogenerators for self-powered nanosystems: quantitative standards and figures of merit

    Science.gov (United States)

    Wu, Wenzhuo

    2016-03-01

    Harvesting energies from the atmosphere cost-effectively is critical for both addressing worldwide long-term energy needs at the macro-scale, and achieving the sustainable maintenance-free operation of nanodevices at the micro-scale (Wang and Wu 2012 Angew. Chem. Int. Ed. 51 11700-21). Piezoelectric nanogenerator (NG) technology has demonstrated its great application potential in harvesting the ubiquitous and abundant mechanical energy. Despite of the progress made in this rapidly-advancing field, a fundamental understanding and common standard for consistently quantifying and evaluating the performance of the various types of piezoelectric NGs is still lacking. In their recent study Crossley and Kar-Narayan (2015 Nanotechnology 26 344001), systematically investigated dynamical properties of piezoelectric NGs by taking into account the effect of driving mechanism and load frequency on NG performance. They further defined the NGs’ figures of merit as energy harvested normalized by applied strain or stress for NGs under strain-driven or stress-driven conditions, which are commonly seen in the vibrational energy harvesting. This work provides new insight and a feasible approach for consistently evaluating piezoelectric nanomaterials and NG devices, which is important for designing and optimizing nanoscale piezoelectric energy harvesters, as well as promoting their applications in emerging areas e.g. the internet of things, wearable devices, and self-powered nanosystems.

  6. Multifunctional TENG for Blue Energy Scavenging and Self-Powered Wind-Speed Sensor

    KAUST Repository

    Xi, Yi

    2017-02-17

    Triboelectric nanogenerator (TENG) has been considered to be a more effective technology to harvest various types of mechanic vibration energies such as wind energy, water energy in the blue energy, and so on. Considering the vast energy from the blue oceans, harvesting of the water energy has attracted huge attention. There are two major types of “mechanical” water energy, water wave energy in random direction and water flow kinetic energy. However, although the most reported TENG can be used to efficiently harvest one type of water energy, to simultaneously collect two or more types of such energy still remains challenging. In this work, two different freestanding, multifunctional TENGs are successfully developed that can be used to harvest three types of energies including water waves, air flowing, and water flowing. These two new TENGs designed in accordance with the same freestanding model yield the output voltages of 490 and ≈100 V with short circuit currents of 24 and 2.7 µA, respectively, when operated at a rotation frequency of 200 rpm and the movement frequency of 3 Hz. Moreover, the developed multifunctional TENG can also be explored as a self-powered speed sensor of wind by correlating the short-circuit current with the wind speed.

  7. Industrial tests of rhodium self-powered detectors: the Golfech 2 experimentation

    International Nuclear Information System (INIS)

    Mourlevat, J.L.; Janvier, D.; Warren, H.D.

    2000-01-01

    In co-operation with Electricite de France (EDF), FRAMATOME has been testing two in-core strings which are equipped with rhodium self-powered detectors (SPDs) in the Golfech Unit 2 reactor (1300 MW, 4L plant) since August 1997. The rhodium SPDs and the strings which support them were designed and built by the US FRAMATOME subsidiary FRAMATOME-COGEMA-FUEL (FCF). The rhodium signals and some other plant parameters are acquired through the use of a specific device designed by the CEA (Commissariat a l'Energie Atomique) and are processed off-line by FRAMATOME. This demonstration test is planned to last until mid-2000. The following presentation is focused on the results obtained during the first demonstration cycle (from 08/97 to 12/98). The tests that have been conducted consist of checking the rhodium depletion and of comparing the rhodium signals to the movable probes. In order to compensate for the delay in the rhodium signals, a deconvolution algorithm has also been tested. Up to now, the results are very satisfactory and a future large scale industrial application is being discussed with the EDF. The main objective of the next experimentation phase is to test - under industrial conditions - a prototype of an on-line monitoring unit known as the Partial In-Core Monitoring System (PIMS). This system will include 16 rhodium in-core strings and will use an on-line 3-D core model. (authors)

  8. Self-powered photogalvanic phosphorene photodetectors with high polarization sensitivity and suppressed dark current.

    Science.gov (United States)

    Li, Shuaishuai; Wang, Tao; Chen, Xiaoshuang; Lu, Wei; Xie, Yiqun; Hu, Yibin

    2018-04-26

    High polarization sensitivity, suppressed dark current and low energy consumption are all desirable device properties for photodetectors. In this work, we propose phosphorene-based photodetectors that are driven using photogalvanic effects (PGEs). The inversion symmetry of pristine phosphorene is broken using either application of an out-of-plane gate voltage or a heterostructure that is composed of the original phosphorene and blue phosphorene. The potential asymmetry enables PGEs under illumination by polarized light. Quantum transport calculations show that robust photocurrents are indeed generated by PGEs under a zero external bias voltage because of the broken inversion symmetry. These results indicate that the proposed photodetector is self-powered. In addition, the zero bias voltage eliminates the dark currents that are caused by application of an external bias voltage to traditional photodetectors. High polarization sensitivity to both linearly and circularly polarized light can also be realized, with extinction ratios ranging up to 102. The photoresponse of the proposed phosphorene/blue phosphorene heterostructure can be greatly enhanced by gating and is several orders of magnitude higher than that in gated phosphorene.

  9. Flexible and multi-directional piezoelectric energy harvester for self-powered human motion sensor

    Science.gov (United States)

    Kim, Min-Ook; Pyo, Soonjae; Oh, Yongkeun; Kang, Yunsung; Cho, Kyung-Ho; Choi, Jungwook; Kim, Jongbaeg

    2018-03-01

    A flexible piezoelectric strain energy harvester that is responsive to multi-directional input forces produced by various human motions is proposed. The structure of the harvester, which includes a polydimethylsiloxane (PDMS) bump, facilitates the effective conversion of strain energy, produced by input forces applied in random directions, into electrical energy. The structural design of the PDMS bump and frame as well as the slits in the piezoelectric polyvinylidene fluoride (PVDF) film provide mechanical flexibility and enhance the strain induced in the PVDF film under input forces applied at various angles. The amount and direction of the strain induced in PVDF can be changed by the direction of the applied force; thus, the generated output power can be varied. The measured maximum output peak voltage is 1.75, 1.29, and 0.98 V when an input force of 4 N (2 Hz) is applied at angles of 0°, 45°, and 90°, and the corresponding maximum output power is 0.064, 0.026, and 0.02 μW, respectively. Moreover, the harvester stably generates output voltage over 1.4 × 104 cycles. Thus, the proposed harvester successfully identifies and converts strain energy produced by multi-directional input forces by various human motions into electrical energy. We demonstrate the potential utility of the proposed flexible energy harvester as a self-powered human motion sensor for wireless healthcare systems.

  10. Synthesis of Samarium Cobalt Nanoblades

    Energy Technology Data Exchange (ETDEWEB)

    Darren M. Steele

    2010-08-25

    As new portable particle acceleration technologies become feasible the need for small high performance permanent magnets becomes critical. With particle accelerating cavities of a few microns, the photonic crystal fiber (PCF) candidate demands magnets of comparable size. To address this need, samarium cobalt (SmCo) nanoblades were attempted to be synthesized using the polyol process. Since it is preferable to have blades of 1-2 {micro}m in length, key parameters affecting size and morphology including method of stirring, reaction temperature, reaction time and addition of hydroxide were examined. Nanoparticles consisting of 70-200 nm spherical clusters with a 3-5 nm polyvinylpyrrolidone (PVP) coating were synthesized at 285 C and found to be ferromagnetic. Nanoblades of 25nm in length were observed at the surface of the nanoclusters and appeared to suggest agglomeration was occurring even with PVP employed. Morphology and size were characterized using a transmission electron microscope (TEM). Powder X-Ray Diffraction (XRD) analysis was conducted to determine composition but no supportive evidence for any particular SmCo phase has yet been observed.

  11. Cobalt: A vital element in the aircraft engine industry

    Science.gov (United States)

    Stephens, J. R.

    1981-01-01

    Recent trends in the United States consumption of cobalt indicate that superalloys for aircraft engine manufacture require increasing amounts of this strategic element. Superalloys consume a lion's share of total U.S. cobalt usage which was about 16 million pounds in 1980. In excess of 90 percent of the cobalt used in this country was imported, principally from the African countries of Zaire and Zambia. Early studies on the roles of cobalt as an alloying element in high temperature alloys concentrated on the simple Ni-Cr and Nimonic alloy series. The role of cobalt in current complex nickel base superalloys is not well defined and indeed, the need for the high concentration of cobalt in widely used nickel base superalloys is not firmly established. The current cobalt situation is reviewed as it applies to superalloys and the opportunities for research to reduce the consumption of cobalt in the aircraft engine industry are described.

  12. Assessment of cobalt levels in wastewater, soil and vegetable ...

    African Journals Online (AJOL)

    User

    Key words: Cobalt level, Kubanni River, soil, vegetable, wastewater. INTRODUCTION. Cobalt is ... metals released into the environment from a variety of anthropogenic activities ..... Heavy Metal Stress in Plants, 2nd Edition,. Springer,. United.

  13. Synthesis and phosphatase activity of a Cobalt(II) phenanthroline ...

    Indian Academy of Sciences (India)

    MAMONI GARAI

    2017-09-19

    Sep 19, 2017 ... Synthesis and phosphatase activity of a Cobalt(II) phenanthroline complex. MAMONI GARAIa ... tion, cobalt complexes have gained importance because of their application as ... 2.3 Physical measurements. Infrared spectrum ...

  14. Certification of a nickel metal reference material for neutron dosimetry (EC Nuclear Reference Material 521)

    International Nuclear Information System (INIS)

    Pauwels, J.

    1988-01-01

    Nickel metal, of 99.99 % nominal purity and natural isotopic composition, in the form of 0.1 mm thick foil and 0.5 mm diameter wire has been certified for its cobalt mass fraction. The certified value of cobalt (<0.1μg.g-1) is based on 38 results obtained by neutron activation analysis, emission spectrometry with inductively coupled plasma excitation and atomic absorption spectrometry, whereas the isotopic composition of the nickel was verified by thermal ionization mass spectrometry. The material is intended to be used as a reference material in neutron metrology

  15. The physiological effect of cobalt on watermelon cultivation

    International Nuclear Information System (INIS)

    Yao Naihua; Jin Yafang; Sun Yaochen; Huang Yiming

    1993-01-01

    Cobalt has essential physiological action on both animals and plants. For the latter it can raise plant's nitrogen-fixing ability and saccharine content. Spray of cobalt mixed with other nutritive elements can improve the germinatit of seeds and the yield of fruit. For specifying the nutritive function of cobalt upon watermelon, isotope 60 Co was mixed into a complex leaf nutritive aqua and the regularity of transferring and absorbing cobalt in the watermelon's body was investigated

  16. Relaxation resistance of heat resisting alloys with cobalt

    International Nuclear Information System (INIS)

    Borzdyka, A.M.

    1977-01-01

    Relaxation resistance of refractory nickel-chromium alloys containing 5 to 14 % cobalt is under study. The tests involve the use of circular samples at 800 deg to 850 deg C. It is shown that an alloy containing 14% cobalt possesses the best relaxation resistance exceeding that of nickel-chromium alloys without any cobalt by a factor of 1.5 to 2. The relaxation resistance of an alloy with 5% cobalt can be increased by hardening at repeated loading

  17. Manipulating radicals: Using cobalt to steer radical reactions

    OpenAIRE

    Chirilă, A.

    2017-01-01

    This thesis describes research aimed at understanding and exploiting metallo-radical reactivity and explores reactions mediated by square planar, low-spin cobalt(II) complexes. A primary goal was to uncover novel reactivity of discrete cobalt(III)-bound carbene radicals generated upon reaction of the cobalt(II) catalysts with carbene precursors. Another important goal was to replace cobalt(II)-porphyrin catalysts with cheaper and easier to prepare metallo-radical analogues. Therefore the cata...

  18. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

  19. Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission.

    Science.gov (United States)

    Falk, Magnus; Alcalde, Miguel; Bartlett, Philip N; De Lacey, Antonio L; Gorton, Lo; Gutierrez-Sanchez, Cristina; Haddad, Raoudha; Kilburn, Jeremy; Leech, Dónal; Ludwig, Roland; Magner, Edmond; Mate, Diana M; Conghaile, Peter Ó; Ortiz, Roberto; Pita, Marcos; Pöller, Sascha; Ruzgas, Tautgirdas; Salaj-Kosla, Urszula; Schuhmann, Wolfgang; Sebelius, Fredrik; Shao, Minling; Stoica, Leonard; Sygmund, Cristoph; Tilly, Jonas; Toscano, Miguel D; Vivekananthan, Jeevanthi; Wright, Emma; Shleev, Sergey

    2014-01-01

    Here for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and separate sensing bioelectrodes, supplied with electrical energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymatic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor), and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 µA and 0.57 V, respectively to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen containing buffer. In addition, a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers containing different concentrations of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concentrations in buffers were changed, using only an enzymatic fuel cell as a power supply.

  20. BioRadioTransmitter: a self-powered wireless glucose-sensing system.

    Science.gov (United States)

    Hanashi, Takuya; Yamazaki, Tomohiko; Tsugawa, Wakako; Ikebukuro, Kazunori; Sode, Koji

    2011-09-01

    Although an enzyme fuel cell can be utilized as a glucose sensor, the output power generated is too low to power a device such as a currently available transmitter and operating system, and an external power source is required for operating an enzyme-fuel-cell-based biosensing system. We proposed a novel biosensor that we named BioCapacitor, in which a capacitor serves as a transducer. In this study, we constructed a new BioCapacitor-based system with an added radio-transmitter circuit and a miniaturized enzyme fuel cell. A miniaturized direct-electron-transfer-type compartmentless enzyme fuel cell was constructed with flavin adenine dinucleotide-dependent glucose dehydrogenase complex-based anode and a bilirubin-oxidase-based cathode. For construction of a BioRadioTransmitter wireless sensing system, a capacitor, an ultra-low-voltage charge-pump-integrated circuit, and Hartley oscillator circuit were connected to the miniaturized enzyme fuel cell. A radio-receiver circuit, comprising two field-effect transistors and a coil as an antenna, was used to amplify the signal generated from the biofuel cells. Radio wave signals generated by the BioRadioTransmitter were received, amplified, and converted from alternate to direct current by the radio receiver. When the capacitor discharges in the presence of glucose, the BioRadioTransmitter generates a radio wave, which is monitored by a radio receiver connected wirelessly to the sensing device. Magnitude of the radio wave transmission frequency change observed at the radio receiver was correlated to glucose concentration in the fuel cells. We constructed a stand-alone, self-powered, wireless glucose-sensing system called a BioRadioTransmitter by using a radio transmitter in which the radio wave transmission frequency changes with the glucose concentration in the fuel cell. The BioRadioTransmitter is a significant advance toward construction of an implantable continuous glucose monitor. © 2011 Diabetes Technology Society.

  1. (Na, K)NbO3-Based Ceramics for Self-Powered Energy Harvesting Applications.

    Science.gov (United States)

    Kim, Jinhwan; Koh, Jung-Hyuk

    2015-03-01

    Self-powered energy harvesting technologies have been intensively investigated by employ- ing Pb-free piezoelectric materials. One such Pb-free piezoelectric material, the ceramic 0.97(Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3, was prepared by employing the conventional mixed oxide method. 0.97(Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics were prepared and the effect of sintering temperature on the microstructure, piezoelectric and ferroelectric properties were system- atically investigated for energy harvesting applications. The crystal structure of 0.97(Na0.5K0.5)NbO3- 0.03(Bi0.5Na0.5) TiO3 Pb-free piezoelectric ceramics, sintered at temperatures between 1080 °C and 1160 °C, was examined by X-ray diffraction analysis. The dielectric properties of 0.97(Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics were measured from 1 kHz to 1 MHz for the various sintering temperatures. We expect that optimization of sintering parameters can improve the piezoelectric and ferroelectric properties of 0.97 (Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics for energy harvesting.

  2. Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission.

    Directory of Open Access Journals (Sweden)

    Magnus Falk

    Full Text Available Here for the first time, we detail self-contained (wireless and self-powered biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and separate sensing bioelectrodes, supplied with electrical energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymatic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor, and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 µA and 0.57 V, respectively to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen containing buffer. In addition, a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers containing different concentrations of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concentrations in buffers were changed, using only an enzymatic fuel cell as a power supply.

  3. Evaluation of in-core measurements with self-powered detectors

    International Nuclear Information System (INIS)

    Spoden, E.

    1977-01-01

    A calculational method is presented for transformation of n-β currents into relative thermal neutron fluxes taking into account an epithermal correction. The difference between epithermal corrections with cross section ratios is demonstrated based on calculations with NR approximation and multiplied by the ratio of mean epithermal and thermal first collision probabilities as well as on calculations using the model of infinite dilution. The effects of this difference on axial power density distribution, relative power of the fuel assemblies, and the inhomogeneity coefficients are discussed in the light of a characteristic measurement with rhodium emitter in a WWER-type reactor. The effect of errors in the nuclear data on the mean error of relative thermal neutron flux is evaluated. (author)

  4. Perfluorinated cobalt phthalocyanine effectively catalyzes water electrooxidation

    KAUST Repository

    Morlanes, Natalia Sanchez

    2014-12-08

    Efficient electrocatalysis of water oxidation under mild conditions at neutral pH was achieved by a fluorinated cobalt phthalocyanine immobilized on fluorine-doped tin oxide (FTO) surfaces with an onset potential at 1.7 V vs. RHE. Spectroscopic, electrochemical, and inhibition studies indicate that phthalocyanine molecular species are the operational active sites. Neither free cobalt ions nor heterogeneous cobalt oxide particles or films were observed. During long-term controlled-potential electrolysis at 2 V vs. RHE (phosphate buffer, pH 7), electrocatalytic water oxidation was sustained for at least 8 h (TON ≈ 1.0 × 105), producing about 4 μmol O2 h-1 cm-2 with a turnover frequency (TOF) of about 3.6 s-1 and no measurable catalyst degradation.

  5. Characterization of a Cobalt-Tungsten Interconnect

    DEFF Research Database (Denmark)

    Harthøj, Anders; Holt, Tobias; Caspersen, Michael

    2012-01-01

    is to act both as a diffusion barrier for chromium and provide better protection against high temperature oxidation than a pure cobalt coating. This work presents a characterization of a cobalt-tungsten alloy coating electrodeposited on the ferritic steel Crofer 22 H which subsequently was oxidized in air......A ferritic steel interconnect for a solid oxide fuel cell must be coated in order to prevent chromium evaporation from the steel substrate. The Technical University of Denmark and Topsoe Fuel Cell have developed an interconnect coating based on a cobalt-tungsten alloy. The purpose of the coating...... for 300 h at 800 °C. The coating was characterized with Glow Discharge Optical Spectroscopy (GDOES), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The oxidation properties were evaluated by measuring weight change of coated samples of Crofer 22 H and Crofer 22 APU as a function...

  6. Solubility of cobalt in primary circuit solutions

    International Nuclear Information System (INIS)

    Lambert, I.; Joyer, F.

    1992-01-01

    The solubility of cobalt ferrite (CoFe 2 O 4 ) was measured in PWR primary circuit conditions, in the temperature range 250-350 deg C, and the results were compared with the ones obtained on magnetite and nickel ferrite. As in the former cases, it was found that, in the prevailing primary circuit conditions, the solubility of the cobalt ferrite was minimum at temperatures around 300 deg C, for cobalt as well as for iron. The equilibrium iron concentration is significantly lower than in the case of magnetite. The results are discussed in relation with the POTHY code, based only on thermodynamic laws and data, used for the prediction of the primary circuit chemistry

  7. Total quality management of cobalt-60 sources

    International Nuclear Information System (INIS)

    Malkoske, G.R.

    1999-01-01

    Total Quality Management of Cobalt-60 sources by a supplier requires a life cycle approach to source management. This covers various aspects, including design, manufacturing, installation, field inspection, source surveillance and return of cobalt-60 sources at the end of their useful life. The Total Quality Management approach demonstrates a strong industry commitment to the beneficial use of gamma technology for industrial irradiation applications in both developed nations and in those nations who are developing their infrastructure and techniques for the beneficial use of this technology. MDS Nordion continues to demonstrate its support and commitment to the industry by developing and implementing state-of-the-art standards for the safe use of cobalt-60 sources

  8. Preliminary studies of cobalt complexation in groundwater

    International Nuclear Information System (INIS)

    Warwick, P.; Shaw, P.; Williams, G.M.; Hooker, P.J.

    1988-01-01

    A relatively non-invasive method has been used to separate complexed from free cobalt-60 in groundwater, using the weak cationic adsorption properties of Sephadex gels, and a mobile phase of natural groundwater. Results show the kinetics of Co complex formation in groundwater to be slow, and that the equilibrium position is affected by temperature, cobalt concentration and the ionic/organic strength of the groundwater. The addition of DAEA cellulose to the groundwater to remove humic material, also removed the majority of organic species which absorb UV at 254 nm, but 45% of the original total organic carbon remained, and the amount of complexed cobalt left in solution was only reduced to 76% of its former concentration. This suggests that the completed Co species separated by the method described in this paper are a mixture of inorganic and organic compounds, and studies are therefore continuing to establish their exact nature. (author)

  9. Preliminary studies of cobalt complexation in groundwater

    International Nuclear Information System (INIS)

    Warwick, P.; Shaw, P.; Williams, G.M.; Hooker, P.J.

    1988-01-01

    A relatively non-invasive method has been used to separate complexed from free cobalt-60 in groundwater, using the weak cationic adsorption properties of Sephadex gels, and a mobile phase of natural groundwater. Results show the kinetics of Co complex formation in groundwater to be slow, and that the equilibrium position is affected by temperature, cobalt concentration and the ionic/organic strength of the groundwater. The addition of DEAE cellulose to the groundwater to remove humic material, also removed the majority of organic species with absorb UV at 254 nm, but 45% of the original total organic carbon remained, and the amount of complexed cobalt left in solution was only reduced to 76% of its former concentration. This suggests that the complexed Co species separated by the method described in this paper are a mixture of inorganic and organic compounds, and studies are therefore continuing to establish their exact nature. (orig.)

  10. Palladium-cobalt particles as oxygen-reduction electrocatalysts

    Science.gov (United States)

    Adzic, Radoslav [East Setauket, NY; Huang, Tao [Manorville, NY

    2009-12-15

    The present invention relates to palladium-cobalt particles useful as oxygen-reducing electrocatalysts. The invention also relates to oxygen-reducing cathodes and fuel cells containing these palladium-cobalt particles. The invention additionally relates to methods for the production of electrical energy by using the palladium-cobalt particles of the invention.

  11. 21 CFR 73.1015 - Chromium-cobalt-aluminum oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium-cobalt-aluminum oxide. 73.1015 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1015 Chromium-cobalt-aluminum oxide. (a) Identity. The color additive chromium-cobalt-aluminum oxide is a blue-green pigment obtained by calcining a...

  12. Cobalt-free nickel-base superalloys

    International Nuclear Information System (INIS)

    Koizumi, Yutaka; Yamazaki, Michio; Harada, Hiroshi

    1979-01-01

    Cobalt-free nickel-base cast superalloys have been developed. Cobalt is considered to be a beneficial element to strengthen the alloys but should be eliminated in alloys to be used for direct cycle helium turbine driven by helium gas from HTGR (high temp. gas reactor). The elimination of cobalt is required to avoid the formation of radioactive 60 Co from the debris or scales of the alloys. Cobalt-free alloys are also desirable from another viewpoint, i.e. recently the shortage of the element has become a serious problem in industry. Cobalt-free Mar-M200 type alloys modified by the additions of 0.15 - 0.2 wt% B and 1 - 1.5 wt% Hf were found to have a creep rupture strength superior or comparable to that of the original Mar-M200 alloy bearing cobalt. The ductility in tensile test at 800 0 C, as cast or after prolonged heating at 900 0 C (the tensile test was done without removing the surface layer affected by the heating), was also improved by the additions of 0.15 - 0.2% B and 1 - 1.5% Hf. The morphology of grain boundaries became intricated by the additions of 0.15 - 0.2% B and 1 - 1.5% Hf, to such a degree that one can hardly distinguish grain boundaries by microscopes. The change in the grain boundary morphology was considered, as suggested previously by one of the authors (M.Y.), to be the reason for the improvements in the creep rupture strength and tensile ductility. (author)

  13. Radiation induced ligand loss from cobalt complexes

    International Nuclear Information System (INIS)

    Funston, A. M.; McFadyen, W.D.; Tregloan, P.A.

    2000-01-01

    Full text: Due to the rapid nature of ligand dissociation from cobalt(II) complexes the study of the rate of ligand dissociation necessitates the use of a technique such as pulse radiolysis. This allows the rapid reduction of the corresponding cobalt(III) complex by a reducing radical, such as the aquated electron, to form the cobalt(II) complex. However, to date, no systematic study of either the mechanism of reduction or the influence of the electronic structure on the rate of ligand dissociation has been carried out. In order to understand these processes more fully the mechanism of reduction of a range of related cobalt(III) complexes by the aquated electron and the subsequent rate of ligand dissociation from the resulting cobalt(II) complexes is being investigated. It has been found that a number of processes are observed following the initial rapid reaction of the cobalt(III) complex with the aquated electron. Ultimately ligand loss is observed. Depending upon the complex, the initial processes observed may include the formation of coordinated radicals and electron transfer within the complex. For complexes containing aromatic ligands such as 2,2'-bipyridine, 1,10-phenanthroline and dipyrido[3,2-a:2',3'-c]phenazine the formation of a coordinated radical is observed as the initial reduction step. The kinetics of ligand dissociation of these complexes has been determined. The loss of monodentate ligands is fast and has been indistinguishable from the reduction processes when aromatic ligands are also present in the complex. However, for diamine chelates and diimine chelates spectra of the transient species can be resolved

  14. Neutron Activation analysis of waste water

    International Nuclear Information System (INIS)

    Hernandez H, V.

    1997-01-01

    An instrumental neutron activation analysis for the simultaneous determination of chlorine, bromine, sodium, manganese, cobalt, copper, chromium, zinc, nickel, antimony and iron in waste water is described. They were determined in waste water samples under normal conditions by non-destructive neutron activation simultaneously using a suitable monostandard method. Standardized water samples were used and irradiated in polyethylene ampoules at a neutron flux of 10 13 cm -2 s -1 for periods of 1 minute, 1 and 10 hours. A Ge hyperpure detector was used for your activity determination, with count times of 60, 180, 300 and 600 seconds. The obtained results show than the method can be utilized for the determination of this elements without realize anything previous treatment of the samples. (Author)

  15. Bio-assembled, piezoelectric prawn shell made self-powered wearable sensor for non-invasive physiological signal monitoring

    Science.gov (United States)

    Ghosh, Sujoy Kumar; Mandal, Dipankar

    2017-03-01

    A human interactive self-powered wearable sensor is designed using waste by-product prawn shells. The structural origin of intrinsic piezoelectric characteristics of bio-assembled chitin nanofibers has been investigated. It allows the prawn shell to make a tactile sensor that performs also as a highly durable mechanical energy harvester/nanogenerator. The feasibility and fundamental physics of self-powered consumer electronics even from human perception is highlighted by prawn shells made nanogenerator (PSNG). High fidelity and non-invasive monitoring of vital signs, such as radial artery pulse wave and coughing actions, may lead to the potential use of PSNG for early intervention. It is presumed that PSNG has enormous future aspects in real-time as well as remote health care assessment.

  16. Self-powered gustation electronic skin for mimicking taste buds based on piezoelectric-enzymatic reaction coupling process

    Science.gov (United States)

    Zhao, Tianming; Fu, Yongming; He, Haoxuan; Dong, Chuanyi; Zhang, Linlin; Zeng, Hui; Xing, Lili; Xue, Xinyu

    2018-02-01

    A new self-powered wearable gustation electronic skin for mimicking taste buds has been realized based on enzyme-modified/ZnO nanowire arrays on patterned-electrode flexible substrate. The e-skin can actively taste beverages or fruits without any external electric power. Through the piezoelectric-enzymatic reaction coupling effect, the nanowires can harvest the mechanical energy of body movement and output piezoelectric signal. The piezoelectric output is significantly dependent on the concentration of target analyte. The response for detecting 2 × 10-2 M ascorbic acid (ascorbate acid oxidase@ZnO) is up to 171.747, and the selectivity is high. The response for detecting 50% alcohol (alcohol oxidase@ZnO) is up to 45.867. Our results provide a new research direction for the development of multifunctional e-skin and expand the study scope for self-powered bionic systems.

  17. Valence states of cobalt and crystal structure peculiarities of solid solution YBa2Cu3-xCoxO6+σ

    International Nuclear Information System (INIS)

    Voronin, V.I.; Goshchinskij, B.N.; Mitberg, Eh.B.; Leonidov, I.A.; Kozhevnikov, V.L.

    2000-01-01

    Crystal structure of solid solution YBa 2 Cu 3-x Co x O 6+σ , where x = 0.2, 0.4, 0.6 and 0.8, is studied by the method of powder neutron diffraction. Charge states of the cation are calculated using the interatomic distances obtained. It is shown that cobalt in Cu1 position has valency 3 + and octahedral coordination at x = 0.2 and 0.4. Increase in doping degree involves both transition of a portion of cobalt ions in the positions mentioned to the state with valence 4 + and tetrahedral coordination and partial substitution of copper in Cu2 position [ru

  18. Cation distributions on rapidly solidified cobalt ferrite

    Science.gov (United States)

    De Guire, Mark R.; Kalonji, Gretchen; O'Handley, Robert C.

    1990-01-01

    The cation distributions in two rapidly solidified cobalt ferrites have been determined using Moessbauer spectroscopy at 4.2 K in an 8-T magnetic field. The samples were obtained by gas atomization of a Co0-Fe2O3-P2O5 melt. The degree of cation disorder in both cases was greater than is obtainable by cooling unmelted cobalt ferrite. The more rapidly cooled sample exhibited a smaller departure from the equilibrium cation distribution than did the more slowly cooled sample. This result is explained on the basis of two competing effects of rapid solidification: high cooling rate of the solid, and large undercooling.

  19. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  20. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  1. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  2. Local irradiation effects of one-dimensional ZnO based self-powered asymmetric Schottky barrier UV photodetector

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yaxue [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Qi, Junjie, E-mail: junjieqi@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Biswas, Chandan [Department of Electrical Engineering, University of California Los Angeles, California 90095 (United States); Li, Feng; Zhang, Kui; Li, Xin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Yue, E-mail: yuezhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Key Laboratory of New Energy Materials and Technologies, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-09-15

    A self-powered metal-semiconductor-metal (MSM) UV photodetector was successfully fabricated based on Ag/ZnO/Au structure with asymmetric Schottky barriers. This exhibits excellent performance compared to many previous studies. Very high photo-to-dark current ratio (approximately 10{sup 5}–10{sup 6}) was demonstrated without applying any external bias, and very fast switching time of less than 30 ms was observed during the investigation. Opposite photocurrent direction was generated by irradiating different Schottky diodes in the fabricated photodetector. Furthermore, the device performance was optimized by largely irradiating both the ZnO microwire (MW) junctions. Schottky barrier effect theory and O{sub 2} adsorption–desorption theories were used to investigate the phenomenon. The device has potential applications in self-powered UV detection field and can be used as electrical power source for electronic, optoelectronic and mechanical devices. - Highlights: • A self-powered Schottky barrier UV photodetector based on 1-D ZnO is fabricated. • For the first time we investigate the local irradiation effects of UV detector. • Irradiating both the junctions and ZnO can optimize the performance of the device.

  3. A machine-learning approach for damage detection in aircraft structures using self-powered sensor data

    Science.gov (United States)

    Salehi, Hadi; Das, Saptarshi; Chakrabartty, Shantanu; Biswas, Subir; Burgueño, Rigoberto

    2017-04-01

    This study proposes a novel strategy for damage identification in aircraft structures. The strategy was evaluated based on the simulation of the binary data generated from self-powered wireless sensors employing a pulse switching architecture. The energy-aware pulse switching communication protocol uses single pulses instead of multi-bit packets for information delivery resulting in discrete binary data. A system employing this energy-efficient technology requires dealing with time-delayed binary data due to the management of power budgets for sensing and communication. This paper presents an intelligent machine-learning framework based on combination of the low-rank matrix decomposition and pattern recognition (PR) methods. Further, data fusion is employed as part of the machine-learning framework to take into account the effect of data time delay on its interpretation. Simulated time-delayed binary data from self-powered sensors was used to determine damage indicator variables. Performance and accuracy of the damage detection strategy was examined and tested for the case of an aircraft horizontal stabilizer. Damage states were simulated on a finite element model by reducing stiffness in a region of the stabilizer's skin. The proposed strategy shows satisfactory performance to identify the presence and location of the damage, even with noisy and incomplete data. It is concluded that PR is a promising machine-learning algorithm for damage detection for time-delayed binary data from novel self-powered wireless sensors.

  4. EXAFS Determination of the Structure of Cobalt in Carbon-Supported Cobalt and Cobalt-Molybdenum Sulfide Hydrodesulfurization Catalysts.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Bouwens, S.M.A.M.; Veen, J.A.R. van; Beer, V.H.J. de; Prins, R.

    1991-01-01

    The structure of the cobalt present in carbon-supported Co and Co-Mo sulfide catalysts was studied by means of X-ray absorption spectroscopy at the Co K-edge and by X-ray photoelectron spectroscopy (XPS). Thiophene hydrodesulfurization activities were used to measure the catalytic properties of

  5. Neutron exposure

    International Nuclear Information System (INIS)

    Prillinger, G.; Konynenburg, R.A. van

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. In chapter 6, LWR-PV neutron transport calculations and dosimetry methods and how they are combined to evaluate the neutron exposure of the steel of pressure vessels are discussed. An effort to correlate neutron exposure parameters with damage is made

  6. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Preszler, A.M.; Moon, S.; White, R.S.

    1976-01-01

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J 2 /sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  7. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

    A new, algebraic, method is applied to calculation of neutron albedo from substance to check the claim that use of ultradispersive fuel and moderator of an active core can help to gain in size and mass of the reactor. In a model of isotropic distribution of incident and reflected neutrons it is shown that coherent scattering on separate grains in the case of thermal neutrons increases transport cross section negligibly, however it decreases albedo from a wall of finite thickness because of decrease of substance density. A visible increase of albedo takes place only for neutrons with wave length of the order of the size of a single grain.

  8. Development of SiC Neutron Detector Assembly to Measure the Neutron Flux of the Reactor Core

    Energy Technology Data Exchange (ETDEWEB)

    Park, Se Hwan; Park, June Sic; Shin, Hee Sung; Kim, Ho Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Yong Kyun [Hanyang University, Seoul (Korea, Republic of)

    2012-05-15

    At present, the conventional detector to measure the neutron at harsh environment is a Self Powered Neutron Detector (SPND). Rhodium(Rh)-103 is in the SPND. When neutron is incident on the Rhodium, the neutron capture reaction occurs, and the Rh-103 is converted to Rh-104. The Rh-104 is decayed to Pd-104 by {beta}-decay, and electrons are generated as the decay products. Because of the half life of Rh-104, approximately 5 minutes are required for the SPND output to reach the equilibrium condition. Therefore the on-line monitoring of the nuclear reactor state is limited if the neutron flux in the reactor core is monitored with the SPND. Silicon carbide (SiC) has the possibility to be developed as neutron detector at harsh environment, because the SiC can be operative at high temperature and high neutron flux conditions. Previously, the basic operation properties of the SiC detector were studied. Also, the radiation response of the SiC detector was studied at high neutron and gamma dose rate. The measurement results for an ex-core neutron flux monitor or a neutron flux monitor of the spent fuel were published. The SiC detector was also developed as neutron detector to measure the fissile material with active interrogation method. However, the studies about the development of SiC detector are still limited. In the present work, the radiation damage effect of the SiC detector was studied. The detector structure was determined based on the study, and a neutron detector assembly was made with the SiC detectors. The neutron and gamma-ray response of the detector assembly is presented in this paper. The detector assembly was positioned in the HANARO research reactor core, the performance test was done. The preliminary results are also included in this paper

  9. Passivation and corrosion behaviours of cobalt and cobalt-chromium-molybdenum alloy

    International Nuclear Information System (INIS)

    Metikos-Hukovic, M.; Babic, R.

    2007-01-01

    Passivation and corrosion behaviour of the cobalt and cobalt-base alloy Co30Cr6Mo was studied in a simulated physiological solution containing chloride and bicarbonate ions and with pH of 6.8. The oxido-reduction processes included solid state transformations occurring at the cobalt/electrolyte interface are interpreted using theories of surface electrochemistry. The dissolution of cobalt is significantly suppressed by alloying it with chromium and molybdenum, since the alloy exhibited 'chromium like' passivity. The structural and protective properties of passive oxide films formed spontaneously at the open circuit potential or during the anodic polarization were studied using electrochemical impedance spectroscopy in the wide frequency range

  10. Cobalt reduction of NSSS valve hardfacings for ALARA

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joo Hak; Lee, Sang Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author).

  11. Cobalt reduction of NSSS valve hardfacings for ALARA

    International Nuclear Information System (INIS)

    Kim, Joo Hak; Lee, Sang Sub

    1994-07-01

    This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author)

  12. Detailed evaluation of ET-RR-2 neutronic design: approach to criticality

    International Nuclear Information System (INIS)

    Ashoub, N.; Amin, E.

    2000-01-01

    The ET-RR-2 safety analysis evaluation effort included the assessment of the reactor core nuclear design parameters. The present work complements the previous effort of neutronic calculations using NCNSRC computer code packages. This paper is the first in comprehensive neutronic calculation assessment up to the equilibrium core. It deals with evaluation of neutronic calculation submitted during the early phase of the licensing process; namely the proposal to assemble the first critical core, calculation of power peaking factor and determination of detailed energy group flux distribution in the core particularly in the cobalt irradiation position. The neutronic design criteria are examined qualitatively and quantitatively in the present paper

  13. Water splitting: Taking cobalt in isolation

    Science.gov (United States)

    Wang, Aiqin; Zhang, Tao

    2016-01-01

    The sustainable production of hydrogen is key to the delivery of clean energy in a hydrogen economy; however, lower-cost alternatives to platinum electrocatalysts are needed. Now, isolated, earth-abundant cobalt atoms dispersed over nitrogen-doped graphene are shown to efficiently electrolyse water to generate hydrogen.

  14. Synthesis and Characterization of Cobalt Ferrite Nanoparticles ...

    African Journals Online (AJOL)

    prepared material. It was observed that surface modification such as with silica coating on the cobalt ferrite will have significant effect on the structural and magnetic properties. It is also observed that, silica coated nanoparticles could be used in biomedical applications (Hong et al., 2013). In this work we have chosen sol-gel ...

  15. Nano cobalt oxides for photocatalytic hydrogen production

    KAUST Repository

    Mangrulkar, Priti A.

    2012-07-01

    Nano structured metal oxides including TiO 2, Co 3O 4 and Fe 3O 4 have been synthesized and evaluated for their photocatalytic activity for hydrogen generation. The photocatalytic activity of nano cobalt oxide was then compared with two other nano structured metal oxides namely TiO 2 and Fe 3O 4. The synthesized nano cobalt oxide was characterized thoroughly with respect to EDX and TEM. The yield of hydrogen was observed to be 900, 2000 and 8275 mmol h -1 g -1 of photocatalyst for TiO 2, Co 3O 4 and Fe 3O 4 respectively under visible light. It was observed that the hydrogen yield in case of nano cobalt oxide was more than twice to that of TiO 2 and the hydrogen yield of nano Fe 3O 4 was nearly four times as compared to nano Co 3O 4. The influence of various operating parameters in hydrogen generation by nano cobalt oxide was then studied in detail. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  16. Sputtering on cobalt with noble gas ions

    International Nuclear Information System (INIS)

    Sarholt-Kristensen, L.; Johansen, A.; Johnson, E.

    1983-01-01

    Single crystals of cobalt have been bombarded with 80 keV Ar + ions and with 80 keV and 200 keV Xe + ions in the [0001] direction of the hcp phase and the [111] direction of the fcc phase. The sputtering yield has been measured as function of target temperature (20 0 C-500 0 C), showing a reduction in sputtering yield for 80 keV Ar + ions and 200 keV Xe + ions, when the crystal structure changes from hcp to fcc. In contrast to this, bombardment with 80 keV Xe + ions results in an increase in sputtering yield as the phase transition is passed. Sputtering yields for [111] nickel are in agreement with the sputtering yields for fcc cobalt indicating normal behaviour of the fcc cobalt phase. The higher sputtering yield of [0001] cobalt for certain combinations of ion mass and energy may then be ascribed to disorder induced partly by martensitic phase transformation, partly by radiation damage. (orig.)

  17. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  18. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  19. Measurement of neutron activation cross-sections for elements Co, Ni, Y, Nb, Tm and Au between 12 and 20 MeV

    International Nuclear Information System (INIS)

    Iwasaki, S.; Matsuyama, S.; Ohkubo, T.; Fukuda, H.; Sakuma, M.; Kitamura, M.; Odano, N.

    1995-01-01

    Neutron activation cross-sections for cobalt, nickel, yttrium, niobium, thulium and gold have been measured in the neutron energies from 12 to 20 MeV with the reference cross section of NEA 93 Nb(n,2n) 92m Nb at Tohoku Dynamitron Facility. (author)

  20. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    A safety rod for a nuclear reactor has an inner end portion having a gamma absorption coefficient and neutron capture cross section approximately equal to those of the adjacent shield, a central portion containing materials of high neutron capture cross section and an outer end portion having a gamma absorption coefficient at least equal to that of the adjacent shield

  1. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  2. Neutron holography

    International Nuclear Information System (INIS)

    Beynon, T.D.

    1986-01-01

    the paper concerns neutron holography, which allows an image to be constructed of the surfaces, as well as the interiors, of objects. The technique of neutron holography and its applications are described. Present and future use of the method is briefly outlined. (U.K.)

  3. Neutron source

    International Nuclear Information System (INIS)

    Cason, J.L. Jr.; Shaw, C.B.

    1975-01-01

    A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap

  4. Neutron transport

    International Nuclear Information System (INIS)

    Berthoud, Georges; Ducros, Gerard; Feron, Damien; Guerin, Yannick; Latge, Christian; Limoge, Yves; Santarini, Gerard; Seiler, Jean-Marie; Vernaz, Etienne; Coste-Delclaux, Mireille; M'Backe Diop, Cheikh; Nicolas, Anne; Andrieux, Catherine; Archier, Pascal; Baudron, Anne-Marie; Bernard, David; Biaise, Patrick; Blanc-Tranchant, Patrick; Bonin, Bernard; Bouland, Olivier; Bourganel, Stephane; Calvin, Christophe; Chiron, Maurice; Damian, Frederic; Dumonteil, Eric; Fausser, Clement; Fougeras, Philippe; Gabriel, Franck; Gagnier, Emmanuel; Gallo, Daniele; Hudelot, Jean-Pascal; Hugot, Francois-Xavier; Dat Huynh, Tan; Jouanne, Cedric; Lautard, Jean-Jacques; Laye, Frederic; Lee, Yi-Kang; Lenain, Richard; Leray, Sylvie; Litaize, Olivier; Magnaud, Christine; Malvagi, Fausto; Mijuin, Dominique; Mounier, Claude; Naury, Sylvie; Nicolas, Anne; Noguere, Gilles; Palau, Jean-Marc; Le Pallec, Jean-Charles; Peneliau, Yannick; Petit, Odile; Poinot-Salanon, Christine; Raepsaet, Xavier; Reuss, Paul; Richebois, Edwige; Roque, Benedicte; Royer, Eric; Saint-Jean, Cyrille de; Santamarina, Alain; Serot, Olivier; Soldevila, Michel; Tommasi, Jean; Trama, Jean-Christophe; Tsilanizara, Aime; Behar, Christophe; Provitina, Olivier; Lecomte, Michael; Forestier, Alain; Bender, Alexandra; Parisot, Jean-Francois; Finot, Pierre

    2013-10-01

    This bibliographical note presents a reference book which addresses the study of neutron transport in matter, the study of conditions for a chain reaction and the study of modifications of matter composition due to nuclear reactions. This book presents the main nuclear data, their measurement, assessment and processing, and the spallation. It proposes an overview of methods applied for the study of neutron transport: basic equations and their derived forms, deterministic methods and Monte Carlo method of resolution of the Boltzmann equation, methods of resolution of generalized Bateman equations, methods of time resolution of space kinetics coupled equations. It presents the main calculation codes, discusses the qualification and experimental aspects, and gives an overview of neutron transport applications: neutron transport calculation of reactors, neutron transport coupled with other disciplines, physics of fuel cycle, criticality

  5. Probing fine magnetic particles with neutron scattering

    International Nuclear Information System (INIS)

    Pynn, R.

    1991-01-01

    Because thermal neutrons are scattered both by nuclei and by unpaired electrons, they provide an ideal probe for studying the atomic and magnetic structures of fine-grained magnetic materials, including nanocrystalline solids, thin epitaxial layers, and colloidal suspensions of magnetic particles, known as ferrofluids. Diffraction, surface reflection, and small angle neutron scattering (SANS) are the techniques used. With the exception of surface reflection, these methods are described in this article. The combination of SANS with refractive-index matching and neutron polarisation analysis is particularly powerful because it allows the magnetic and atomic structures to be determined independently. This technique has been used to study both dilute and concentrated ferrofluid suspensions of relatively monodisperse cobalt particles, subjected to a series of applied magnetic fields. The size of the cobalt particle core and the surrounding surfactant layer were determined. The measured interparticle structure factor agrees well with a recent theory that allows correlations in binary mixtures of magnetic particles to be calculated in the case of complete magnetic alignment. When one of the species in such a binary mixture is a nonmagnetic, cyclindrical macromolecule, application of a magnetic field leads to some degree of alignment of the nonmagnetic species. This result has been demonstrated with tobacco mosaic virus suspended in a water-based ferrofluid

  6. Neutron capture cross section standards for BNL-325

    International Nuclear Information System (INIS)

    Holden, N.E.

    1980-01-01

    The most common cross section standards for capture reactions in the thermal neutron energy region are gold, cobalt, and manganese. In preparation for the fourth edition of BNL-325, data on the thermal cross section and resonance integral were evaluated for these three standards. For gold, only measurements below the Bragg scattering cutoff were used and extrapolated to a neutron velocity of 2200 meters/second. A non 1/v correction due to the 4.9 eV resonance was made. The resonance integral is based on Jirlow's integral measurement and Tellier's parameters. The resonance integrals for cobalt and manganese are based solely on integral measurements because the capture widths of the first major resonance either vary by 20% in various measurements (cobalt), or have never been measured (manganese). Recommended thermal cross sections and resonance integrals are respectively gold: 98.65/plus or minus/0.9 barns, 1550/plus or minus/28 barns; cobalt: 37.18/plus or minus/0.06 barns, 74.2/plus or minus/2.0 barns and manganese: 13.3/plus or minus/0.2 barns, and 14.0/plus or minus/0.3 barns. 72 refs

  7. Determination of chromium, cobalt and nickel in tissue samples by radiochemical activation analysis

    International Nuclear Information System (INIS)

    Reisell, A.; Lakomaa, E.L.

    1983-03-01

    A radiochemical neutron activation analysis method for the determination of chromium, cobalt and nickel in tissue samples. A radiochemical neutron activation analysis method for the determination of chromium, cobalt and nickel has been developed. The destruction device used consisted of a combined wet-ashing-distillation and ion-exchange system. Six samples could be treated at the same time. The samples were wet-ashed with H*L2SO*L4-H*L2O*L2 mixture. Volatile elements were distilled as bromide compounds with HBr*H-. The distillation residue in 8M HCl was passed through hydrated antimony pentoxide (HAP) in order to remove disturbing *H2*H4Na-activity and through a Dowex 2 x 8 column so as to retain *H6*H0Co (formed from *H5*H8Ni). Chromium was elutriated from the column and precipitated as Cr(OH)*L3 for the removal of disturbing *H3*H2P-activity. The standards and samples were treated in a similar manner each so that the yield determination is not necessarily needed. The yields by tracer experiments were (43 +- 5) % for Cr, (93 +- 4) % for Co and (88 +- 14) % for Ni. The precision and accuracy of the method were studied by using reference materials of the National Bureau of Standards (NBS) and the International Atomic Energy Agency (IAEA)

  8. ZnO Piezoelectric Nanowires for Use in a Self-Powered Structural Health Monitoring Device for Fiber-Reinforced Composites Uploading Attachment Instructions

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this proposed research is to develop a new self-powered structural health monitoring (SHM) system for fiber-reinforced polymer (FRP) composites by using...

  9. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  10. The cytotoxicity and genotoxicity of soluble and particulate cobalt in human lung fibroblast cells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Leah J.; Holmes, Amie L. [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300 (United States); Maine Center for Environmental Toxicology and Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300 (United States); Department of Applied Medical Science, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300 (United States); Kandpal, Sanjeev Kumar; Mason, Michael D. [Department of Chemical and Biological Engineering, University of Maine, Orono, ME (United States); Zheng, Tongzhang [Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT (United States); Wise, John Pierce, E-mail: John.Wise@usm.maine.edu [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300 (United States); Maine Center for Environmental Toxicology and Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300 (United States); Department of Applied Medical Science, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300 (United States)

    2014-08-01

    Cobalt exposure is increasing as cobalt demand rises worldwide due to its use in enhancing rechargeable battery efficiency, super-alloys, and magnetic products. Cobalt is considered a possible human carcinogen with the lung being a primary target. However, few studies have considered cobalt-induced toxicity in human lung cells. Therefore, in this study, we sought to determine the cytotoxicity and genotoxicity of particulate and soluble cobalt in human lung cells. Cobalt oxide and cobalt chloride were used as representative particulate and soluble cobalt compounds, respectively. Exposure to both particulate and soluble cobalt induced a concentration-dependent increase in cytotoxicity, genotoxicity, and intracellular cobalt ion levels. Based on intracellular cobalt ion levels, we found that soluble cobalt was more cytotoxic than particulate cobalt while particulate and soluble cobalt induced similar levels of genotoxicity. However, soluble cobalt induced cell cycle arrest indicated by the lack of metaphases at much lower intracellular cobalt concentrations compared to cobalt oxide. Accordingly, we investigated the role of particle internalization in cobalt oxide-induced toxicity and found that particle-cell contact was necessary to induce cytotoxicity and genotoxicity after cobalt exposure. These data indicate that cobalt compounds are cytotoxic and genotoxic to human lung fibroblasts, and solubility plays a key role in cobalt-induced lung toxicity. - Highlights: • Particulate and soluble cobalt are cytotoxic and genotoxic to human lung cells. • Soluble cobalt induces more cytotoxicity compared to particulate cobalt. • Soluble and particulate cobalt induce similar levels of genotoxicity. • Particle-cell contact is required for particulate cobalt-induced toxicity.

  11. Changes in the long-term delayed response of platinum self-powered detector with irradiation

    International Nuclear Information System (INIS)

    Parent, G.; Serdula, K.J.; Eng, P.

    1989-01-01

    Two long-term delayed response characteristics have been observed for platinum, Pt, detectors in the Gentilly-2 600 MW(e) CANDU PHWR reactor. The first effect is a dip in the signal two to three hours after a shutdown, due to the (n,beta) interactions of Mn-55 and Ni-64 which exist as impurities in the detector assembly. The second effect is an increase of the delayed fraction of the signal. The low neutron absorption cross-section of Pt-196 combined with the conversion of the Pt-194 and Pt-195 results in build-up of the Pt-196. The long half-lives associated with the beta-emission in the transmutation of Pt-196 to Hg-198 or Hg-199 give rise to the observed long-term delayed response

  12. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  13. Neutronics codes

    International Nuclear Information System (INIS)

    Buckel, G.

    1983-01-01

    The objectives are the development, testing and cultivation of reliable, efficient and user-optimized neutron-physical calculation methods and conformity with users' requirements concerning design of power reactors, planning and analysis of experiments necessary for their protection as well as research on physical key problems. A short outline of available computing programmes for the following objectives is given: - Provision of macroscopic group constants, - Calculation of neutron flux distribution in transport theory and diffusion approximation, - Evaluation of neutron flux-distribution, - Execution of disturbance calculations for the determination reactivity coefficients, and - graphical representation of results. (orig./RW) [de

  14. Piezoelectrically and triboelectrically hybridized self-powered sensor with applications to smart window and human motion detection

    Directory of Open Access Journals (Sweden)

    Yiin-Kuen Fuh

    2017-07-01

    Full Text Available In this paper, we demonstrate a hybrid generator, derived from the concurrent adoption of piezoelectric and triboelectric mechanisms in one press-and-release cycle, called a Hybridized Self-Powered sensor (HSPS. A new integration of print circuit board (PCB technology-based piezoelectric generator (PG concurrently adopted the direct-write, near-field electrospun polyvinylidene fluoride (PVDF nano/micro-fibers as piezoelectric source materials. On the other hand, triboelectric nanogenerators have the advantages of a high output performance with a simple structure which is also concurrently combined with the PG. The working mechanism of the HSPS includes the PCB-based substrate mounted with parallel aligned piezoelectric PVDF fibers in planar configuration which first bended and generated the electric potential via the effect of piezoelectricity. In what follows, the deformation of a cylindrical rolled-up piezoelectric structure is exercised, and finally, the triboelectric contact of Cu and PTFE layers is physically rubbed against each other with a separation to induce the triboelectric potential. This hybridized generator with a double domed shape design simultaneously combines piezoelectric output and triboelectric output and offers a built-in spacer with automatically spring back capability, which produces a peak output voltage of 100 V, a current of 4 μA, and a maximum power output of 450 nW. A self-powered smart window system was experimentally driven through finger-induced strain of HSPS, showing the optical properties with reversibly tunable transmittances. This research is a substantial advancement in the field of piezoelectric PVDF fibers integration toward the practical application of the whole self-powered system.

  15. Piezoelectrically and triboelectrically hybridized self-powered sensor with applications to smart window and human motion detection

    Science.gov (United States)

    Fuh, Yiin-Kuen; Li, Shan-Chien; Chen, Chun-Yu

    2017-07-01

    In this paper, we demonstrate a hybrid generator, derived from the concurrent adoption of piezoelectric and triboelectric mechanisms in one press-and-release cycle, called a Hybridized Self-Powered sensor (HSPS). A new integration of print circuit board (PCB) technology-based piezoelectric generator (PG) concurrently adopted the direct-write, near-field electrospun polyvinylidene fluoride (PVDF) nano/micro-fibers as piezoelectric source materials. On the other hand, triboelectric nanogenerators have the advantages of a high output performance with a simple structure which is also concurrently combined with the PG. The working mechanism of the HSPS includes the PCB-based substrate mounted with parallel aligned piezoelectric PVDF fibers in planar configuration which first bended and generated the electric potential via the effect of piezoelectricity. In what follows, the deformation of a cylindrical rolled-up piezoelectric structure is exercised, and finally, the triboelectric contact of Cu and PTFE layers is physically rubbed against each other with a separation to induce the triboelectric potential. This hybridized generator with a double domed shape design simultaneously combines piezoelectric output and triboelectric output and offers a built-in spacer with automatically spring back capability, which produces a peak output voltage of 100 V, a current of 4 μA, and a maximum power output of 450 nW. A self-powered smart window system was experimentally driven through finger-induced strain of HSPS, showing the optical properties with reversibly tunable transmittances. This research is a substantial advancement in the field of piezoelectric PVDF fibers integration toward the practical application of the whole self-powered system.

  16. Spin density measurement of water-bridged Co-dimer using polarized neutrons

    DEFF Research Database (Denmark)

    Damgaard-Møller, Emil; Overgaard, Jacob; Chilton, Nick

    present an experimentally determined spin density using polarized neutron diffraction in a simple water-bridged cobalt dimer [Co2(H2O)(piv)4(Hpiv)2(py)2] which is known to have a small ferromagnetic coupling between the spin centers. Visualizing the SDD could get us one step further in understanding...

  17. Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor

    Science.gov (United States)

    LeVert, Francis E.; Cox, Samson A.

    1978-01-01

    A self-powered gamma monitor for placement near the core of a nuclear reactor comprises a lead prism surrounded by a coaxial thin nickel sheet, the combination forming a collector. A coaxial polyethylene electron barrier encloses the collector and is separated from the nickel sheet by a vacuum region. The electron barrier is enclosed by a coaxial stainless steel emitter which, in turn, is enclosed within a lead casing. When the detector is placed in a flux of gamma rays, a measure of the current flow in an external circuit between emitter and collector provides a measure of the power level of the reactor.

  18. Threshold self-powered gamma detector for use as a monitor of power in a nuclear reactor

    International Nuclear Information System (INIS)

    LeVert, F.E.; Cox, S.A.

    1978-01-01

    A self-powered gamma monitor for placement near the core of a nuclear reactor comprises a lead prism surrounded by a coaxial thin nickel sheet, the combination forming a collector. A coaxial polyethylene electron barrier encloses the collector and is separated from the nickel sheet by a vacuum region. The electron barrier is enclosed by a coaxial stainless steel emitter which, in turn, is enclosed within a lead casing. When the detector is placed in a flux of gamma rays, a measure of the current flow in an external circuit between emitter and collector provides a measure of the power level of the reactor

  19. Investigation of self-powered gamma flux detectors with Lead(II) oxide serving as both emitter and insulator

    International Nuclear Information System (INIS)

    Shi, H.; Yue, S.; Jonkmans, G.; Sur, B.; Hilborn, J.

    2010-01-01

    The use of Lead(II) oxide as the electron-emitting component and the insulating component of self-powered flux detectors is a concept that had not been previously explored. Detectors constructed from various combinations of electrodes (stainless steel, Al, Pb, and W) and insulating materials (Al 2 O 3 and PbO) were irradiated in a 427 Gy/h gamma field. Although high gamma sensitivities were achieved, PbO did not prove to be a strong emitter of gamma-induced electrons. Nevertheless, PbO did serve as a better insulator than one that is currently in use, namely alumina. (author)

  20. Implantable Self-Powered Low-Level Laser Cure System for Mouse Embryonic Osteoblasts' Proliferation and Differentiation.

    Science.gov (United States)

    Tang, Wei; Tian, Jingjing; Zheng, Qiang; Yan, Lin; Wang, Jiangxue; Li, Zhou; Wang, Zhong Lin

    2015-08-25

    Bone remodeling or orthodontic treatment is usually a long-term process. It is highly desirable to speed up the process for effective medical treatment. In this work, a self-powered low-level laser cure system for osteogenesis is developed using the power generated by the triboelectric nanogenerator. It is found that the system significantly accelerated the mouse embryonic osteoblasts' proliferation and differentiation, which is essential for bone and tooth healing. The system is further demonstrated to be driven by a living creature's motions, such as human walking or a mouse's breathing, suggesting its practical use as a portable or implantable clinical cure for bone remodeling or orthodontic treatment.

  1. Cobalt Fischer-Tropsch catalysts: influence of cobalt dispersion and titanium oxides promotion

    Energy Technology Data Exchange (ETDEWEB)

    Azib, H

    1996-04-10

    The aim of this work is to study the effect of Sol-Gel preparation parameters which occur in silica supported cobalt catalysts synthesis. These catalysts are particularly used for the waxes production in natural gas processing. The solids have been characterized by several techniques: transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), programmed temperature reduction (TPR), infrared spectroscopy (IR), ultraviolet spectroscopy (UV), Magnetism, thermodesorption of H{sub 2} (TPD). The results indicate that the control of the cobalt dispersion and oxide phases nature is possible by modifying Sol-Gel parameters. The catalytic tests in Fischer-Tropsch synthesis were conducted on a pilot unit under pressure (20 atm) and suggested that turnover rates were independent of Co crystallite size, Co phases in the solids (Co deg., cobalt silicate) and titanium oxide promotion. On the other methane, the C{sub 3}{sup +} hydrocarbon selectivity is increased with increasing crystallite size. Inversely, the methane production is favoured by very small crystallites, cobalt silicate increase and titanium addition. However, the latter, used as a cobalt promoter, has a benefic effect on the active phase stability during the synthesis. (author). 149 refs., 102 figs., 71 tabs.

  2. Electrocatalytic performance evaluation of cobalt hydroxide and cobalt oxide thin films for oxygen evolution reaction

    Science.gov (United States)

    Babar, P. T.; Lokhande, A. C.; Pawar, B. S.; Gang, M. G.; Jo, Eunjin; Go, Changsik; Suryawanshi, M. P.; Pawar, S. M.; Kim, Jin Hyeok

    2018-01-01

    The development of an inexpensive, stable, and highly active electrocatalyst for oxygen evolution reaction (OER) is essential for the practical application of water splitting. Herein, we have synthesized an electrodeposited cobalt hydroxide on nickel foam and subsequently annealed in an air atmosphere at 400 °C for 2 h. In-depth characterization of all the films using X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) techniques, which reveals major changes for their structural, morphological, compositional and electrochemical properties, respectively. The cobalt hydroxide nanosheet film shows high catalytic activity with 290 mV overpotential at 10 mA cm-2 and 91 mV dec-1 Tafel slope and robust stability (24 h) for OER in 1 M KOH electrolyte compared to cobalt oxide (340 mV). The better OER activity of cobalt hydroxide in comparison to cobalt oxide originated from high active sites, enhanced surface, and charge transport capability.

  3. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films......Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index...

  4. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

    This report contains the text of 16 lectures given at the Summer School and the report on a panel discussion entitled ''the relative merits and complementarities of x-rays, synchrotron radiation, steady- and pulsed neutron sources''. figs., tabs., refs

  5. Neutron activation analysis in reconnaissance geochemical survey of Northwestern Mindoro

    International Nuclear Information System (INIS)

    Santos, G. Jr.; Fernandez, L.G.

    1987-01-01

    Instrumental neutron activation analysis (NAA) technique was used to analyze stream sediments collected in Northwestern Mindoro. The concentration levels of 18 elements were determined. It was noted that NAA is suitable for the determination of rare earth, gold, arsenic and cobalt among others because of favorable high neutron cross sections. Samples collected in regional reconnaissance geochemical surveys could be analyzed usng NAA technique to complement other non-nuclear techniques, such as atomic absorption and X-ray fluorescence analysis. (Author). 11 figs.; 2 tabs.; 12 refs

  6. Notes on neutron flux measurement; Notas sobre medida de flujos neutronicos

    Energy Technology Data Exchange (ETDEWEB)

    Alcala Ruiz, F

    1984-07-01

    The main purpose of this work is to get an useful guide to carry out topical neutron flux measurements. Although the foil activation technique is used in the majority of the cases, other techniques, such as those based on fission chambers and self-powered neutron detectors, are also shown. Special interest is given to the description and application of corrections on the measurement of relative and absolute induced activities by several types of detectors (scintillators, G-M and gas proportional counters). The thermal arid epithermal neutron fluxes, as determined in this work, are conventional or effective (West cots fluxes), which are extensively used by the reactor experimentalists; however, we also give some expressions where they are related to the integrated neutron fluxes, which are used in neutron calculations. (Author) 16 refs.

  7. Neutron storage

    International Nuclear Information System (INIS)

    Strelkov, A.V.

    2004-01-01

    The report is devoted to neutron storage (NS) and describes the history of experiments on the NS development. Great attention is paid to ultracold neutron (UCN) storage. The experiments on the UCN generation, transport, spectroscopy, storage and detection are described. Experiments on searching the UCN electric-dipole moment and electric charge are continued. Possible using of UCN for studying the nanoparticles is discussed [ru

  8. Neutron radiography

    International Nuclear Information System (INIS)

    Bayon, G.

    1989-01-01

    Neutronography or neutron radiography, a non-destructive test method which is similar in its principle to conventional X-ray photography, presently occupies a marginal position among non-destructive test methods (NDT) (no source of suitable performance or cost). Neutron radiography associated with the ORPHEE reactor permits industrial testing; it can very quickly meet a cost requirement comparable to that of conventional test methods. In 1988, 2500 parts were tested on this unit [fr

  9. A computer controlled tele-cobalt unit

    International Nuclear Information System (INIS)

    Brace, J.A.

    1982-01-01

    A computer controlled cobalt treatment unit was commissioned for treating patients in January 1980. Initially the controlling computer was a minicomputer, but now the control of the therapy unit is by a microcomputer. The treatment files, which specify the movement and configurations necessary to deliver the prescribed dose, are produced on the minicomputer and then transferred to the microcomputer using minitape cartridges. The actual treatment unit is based on a standard cobalt unit with a few additional features e.g. the drive motors can be controlled either by the computer or manually. Since the treatment unit is used for both manual and automatic treatments, the operational procedure under computer control is made to closely follow the manual procedure for a single field treatment. The necessary safety features which protect against human, hardware and software errors as well as the advantages and disadvantages of computer controlled radiotherapy are discussed

  10. Creep-fatigue of low cobalt superalloys

    Science.gov (United States)

    Halford, G. R.

    1982-01-01

    Testing for the low cycle fatigue and creep fatigue resistance of superalloys containing reduced amounts of cobalt is described. The test matrix employed involves a single high temperature appropriate for each alloy. A single total strain range, again appropriate to each alloy, is used in conducting strain controlled, low cycle, creep fatigue tests. The total strain range is based upon the level of straining that results in about 10,000 cycles to failure in a high frequency (0.5 Hz) continuous strain-cycling fatigue test. No creep is expected to occur in such a test. To bracket the influence of creep on the cyclic strain resistance, strain hold time tests with ore minute hold periods are introduced. One test per composition is conducted with the hold period in tension only, one in compression only, and one in both tension and compression. The test temperatures, alloys, and their cobalt compositions that are under study are given.

  11. Process for obtaining cobalt and lanthanum nickelate

    International Nuclear Information System (INIS)

    Tapcov, V.; Samusi, N.; Gulea, A.; Horosun, I.; Stasiuc, V.; Petrenco, P.

    1999-01-01

    The invention relates to the process for obtaining polycrystalline ceramics of cobalt and lanthanum nickelate with the perovskite structure from coordinative hetero metallic compounds. The obtained products can be utilized in the industry in the capacity of catalysts. Summary of the invention consists in obtaining polycrystalline ceramics LaCoO 3 and LaNiO 3 with the perovskite structure by pyrolysis of the parent compounds, namely, the coordinative hetero metallic compounds of the lanthanum cobalt or lanthanum nickel. The pyrolysis of the parent compound runs during one hour at 800 C. The technical result of the invention consists in lowering the temperature of the parent compound pyrolysis containing the precise ratio of metals necessary for ceramics obtaining

  12. Cobalt oxides from crystal chemistry to physics

    CERN Document Server

    Raveau, Bernard

    2012-01-01

    Unparalleled in the breadth and depth of its coverage of all important aspects, this book systematically treats the electronic and magnetic properties of stoichiometric and non-stoichiometric cobaltites in both ordered and disordered phases. Authored by a pioneer and a rising star in the field, the monograph summarizes, organizes and streamlines the otherwise difficult-to-obtain information on this topic. An introductory chapter sets forth the crystal chemistry of cobalt oxides to lay the groundwork for an understanding of the complex phenomena observed in this materials class. Special emphasis is placed on a comprehensive discussion of cobaltite physical properties in different structural families. Providing a thorough introduction to cobalt oxides from a chemical and physical viewpoint as a basis for understanding their intricacies, this is a must-have for both experienced researchers as well as entrants to the field.

  13. Sorption of cobalt in zeolites and natural clays of the clinoptilolite and kaolinite type; Sorcion de cobalto en zeolitas y arcillas naturales del tipo clinoptilolita y caolinita

    Energy Technology Data Exchange (ETDEWEB)

    Davila R, J.I.; Solache R, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2006-07-01

    In this work the sorption of cobalt of aqueous solutions in two natural zeolites (clinoptilolite) and a clay (kaolinite) of origin in the center-north region of Mexico is evaluated. The effect of the pH and the time of contact in the process of sorption were evaluated. The cobalt retained in the aluminosilicates was determined by neutron activation analysis. The cobalt sorption in the materials in a range of pH from 4 to 7 does not present significant variations. The studies of reaction kinetics show a very fast sorption in the first 5 hours of contact, reaching the equilibrium in approximately 24 hours. The kinetics of sorption of the cobalt ions was represented better by the Ritchie reaction model modified of second order. The experimental data for the zeolites obtained at ambient temperature and varying the concentration were adjusted to the models of Freundlich, Langmuir and Freundlich-Langmuir isotherms and it was observed that the cobalt sorption it behaves according to the Freundlich isotherm model. (Author)

  14. Neutron detector

    International Nuclear Information System (INIS)

    Endo, Hiroshi.

    1993-01-01

    The device of the present invention detects neutrons in a reactor container under a high temperature and reduces the noise level in an FBR type reactor. That is, the detection section comprises a high heat resistant vessel containing a scintillator therein for detecting neutrons. Neutron signals sent from the detection section are inputted to a neutron measuring section by way of a signal transmission section. The detection section is disposed at the inside of the reactor container. Further, the signal transmission section is connected optically to the detection section. With such a constitution, since the detection section comprising the high temperature resistant vessel is disposed at the inside of the reactor container, neutron fluxes can be detected and measured at high sensitivity even under a high temperature circumstance. Since the signal transmission section is optically connected to the detection section, influence of radiation rays upon transmission of the neutron detection signals can be reduced. Accordingly, the noise level can be kept low. (I.S.)

  15. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

    The neutron probe is a standard tool for measuring soil water content. This article provides an overview of the underlying theory, describes the methodology for its calibration and use, discusses example applications, and identifies the safety issues. Soil water makes land-based life possible by satisfying plant water requirements, serving as a medium for nutrient movement to plant roots and nutrient cycling, and controlling the fate and transport of contaminants in the soil environment. Therefore, a successful understanding of the dynamics of plant growth, nutrient cycling, and contaminant behavior in the soil requires knowledge of the soil water content as well as its spatial and temporal variability. After more than 50 years, neutron probes remain the most reliable tool available for field monitoring of soil water content. Neutron probes provide integrated measurements over relatively large volumes of soil and, with proper access, allow for repeated sampling of the subsurface at the same locations. The limitations of neutron probes include costly and time-consuming manual operation, lack of data automation, and costly regulatory requirements. As more non-radioactive systems for soil water monitoring are developed to provide automated profiling capabilities, neutron-probe usage will likely decrease. Until then, neutron probes will continue to be a standard for reliable measurements of field water contents in soils around the globe

  16. Photoionization of cobalt impuritiesin zinc oxide

    Czech Academy of Sciences Publication Activity Database

    Ivanov, V.; Godlewski, M.; Dejneka, Alexandr

    2015-01-01

    Roč. 252, č. 9 (2015), s. 1988-1992 ISSN 0370-1972 R&D Projects: GA MŠk(CZ) LM2011029; GA ČR GAP108/12/1941 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : absorption band * cobalt * photoionization * electron spin resonance * pulsed mode * ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.522, year: 2015

  17. Speciation studies of cobalt in sea water

    International Nuclear Information System (INIS)

    Toteja, R.S.D.; Sudersanan, M.; Iyer, R.K.

    1995-01-01

    Recent results on the speciation of cobalt in simulated and actual sea water is reported using ion exchangers. The influence of magnesium ions in affecting the composition of ion exchangers and subsequent interpretation of the results is discussed. The results indicated that Co +2 may predominate in both the simulated and actual sea water and the presence of other constituents in sea water does not affect the nature of complex species present. (author). 2 refs., 3 tabs., 1 fig

  18. Literature study on the physiology of cobalt

    International Nuclear Information System (INIS)

    Erzberger, A.

    1986-12-01

    This literature study analyses the metabolism of cobalt in the human body, focussing on its resorption and the influence of various parameters like its chemical form, antagonisms, etc. on the level of resorption rate. The value currently recommended by ICRP for resorption rates (f 1 factor) of 0,3 or 0,05 for man is examined for its confirmation or non-confirmation in literature. (orig./MG) [de

  19. Enhanced magnetocrystalline anisotropy in deposited cobalt clusters

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, D.A.; Denby, P.M.; Kirkman, I.W. [Daresbury Laboratory, Daresbury, Warrington (United Kingdom); Harrison, A.; Whittaker, A.G. [Department of Chemistry, University of Edinburgh, Edinburgh (United Kingdom)

    2002-01-28

    The magnetic properties of nanomaterials made by embedding cobalt nanocrystals in a copper matrix have been studied using a SQUID magnetometer. The remanent magnetization at temperatures down to 1.8 K and the RT (room temperature) field-dependent magnetization of 1000- and 8000-atom (average-size) cobalt cluster samples have been measured. In all cases it has been possible to relate the morphology of the material to the magnetic properties. However, it is found that the deposited cluster samples contain a majority of sintered clusters even at cobalt concentrations as low as 5% by volume. The remanent magnetization of the 8000-atom samples was found to be bimodal, consisting of one contribution from spherical particles and one from touching (sintered) clusters. Using a Monte Carlo calculation to simulate the sintering it has been possible to calculate a size distribution which fits the RT superparamagnetic behaviour of the 1000-atom samples. The remanent magnetization for this average size of clusters could then be fitted to a simple model assuming that all the nanoparticles are spherical and have a size distribution which fits the superparamagnetic behaviour. This gives a value for the potential energy barrier height (for reversing the spin direction) of 2.0 {mu}eV/atom which is almost four times the accepted value for face-centred-cubic bulk cobalt. The remanent magnetization for the spherical component of the large-cluster sample could not be fitted with a single barrier height and it is conjectured that this is because the barriers change as a function of cluster size. The average value is 1.5 {mu}eV/atom but presumably this value tends toward the bulk value (0.5 {mu}eV/atom) for the largest clusters in this sample. (author)

  20. Cobalt metabolism and toxicology-A brief update

    Energy Technology Data Exchange (ETDEWEB)

    Simonsen, Lars Ole, E-mail: LOSimonsen@dadlnet.dk; Harbak, Henrik; Bennekou, Poul

    2012-08-15

    Cobalt metabolism and toxicology are summarized. The biological functions of cobalt are updated in the light of recent understanding of cobalt interference with the sensing in almost all animal cells of oxygen deficiency (hypoxia). Cobalt (Co{sup 2+}) stabilizes the transcriptional activator hypoxia-inducible factor (HIF) and thus mimics hypoxia and stimulates erythropoietin (Epo) production, but probably also by the same mechanism induces a coordinated up-regulation of a number of adaptive responses to hypoxia, many with potential carcinogenic effects. This means on the other hand that cobalt (Co{sup 2+}) also may have beneficial effects under conditions of tissue hypoxia, and possibly can represent an alternative to hypoxic preconditioning. Cobalt is acutely toxic in larger doses, and in mammalian in vitro test systems cobalt ions and cobalt metal are cytotoxic and induce apoptosis and at higher concentrations necrosis with inflammatory response. Cobalt metal and salts are also genotoxic, mainly caused by oxidative DNA damage by reactive oxygen species, perhaps combined with inhibition of DNA repair. Of note, the evidence for carcinogenicity of cobalt metal and cobalt sulfate is considered sufficient in experimental animals, but is as yet considered inadequate in humans. Interestingly, some of the toxic effects of cobalt (Co{sup 2+}) have recently been proposed to be due to putative inhibition of Ca{sup 2+} entry and Ca{sup 2+}-signaling and competition with Ca{sup 2+} for intracellular Ca{sup 2+}-binding proteins. The tissue partitioning of cobalt (Co{sup 2+}) and its time-dependence after administration of a single dose have been studied in man, but mainly in laboratory animals. Cobalt is accumulated primarily in liver, kidney, pancreas, and heart, with the relative content in skeleton and skeletal muscle increasing with time after cobalt administration. In man the renal excretion is initially rapid but decreasing over the first days, followed by a second, slow

  1. Uptake of radionuclides caesium and cobalt

    International Nuclear Information System (INIS)

    Lukac, P.; Foldesova, M.

    1995-01-01

    By means of chemical treatment ammonium, potassium, sodium and H-form of zeolite were prepared. The chemical modifications of zeolite were carried out with: 2M solution of NaNO 3 , NH 4 NO 3 , KNO 3 ; 0,1M solution of HCl; NaOH solution of different concentration. The method of model radioactive solution was used to find the sorption ability for cesium and cobalt every modified zeolite. The model solution were 0.05M solution of cobalt labelled by 60 Co or cesium labelled by 137 Cs. The highest sorption ability was observed for zeolite modified by NaOH. The influence of pH on uptake of cesium and cobalt by modified zeolite was searched as well. The experimental data (leaching tests, compressive strength measurement and porosity) were measured for the case the Cs and Cs from model water solution and radioactive waste water were up taken on chemically modified zeolite and were subsequently incorporated into cement casts on blast furnace cement slags basis. The leachability was tested in water, in basis solution and in acid solution. The leachability in water and basic solution was negligible, in acid solution it was less than 4% which is inside of value of applied measure method. The compressive strength, porosity and leaching experiment are hopefully and show good mechanical stability and good retention of observed radionuclides in samples exposed in leaching solutions. (J.K.)

  2. Uptake of radionuclides caesium and cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Lukac, P; Foldesova, M [Slovak Technical Univ., Bratislava (Slovakia)

    1996-12-31

    By means of chemical treatment ammonium, potassium, sodium and H-form of zeolite were prepared. The chemical modifications of zeolite were carried out with: 2M solution of NaNO{sub 3}, NH{sub 4}NO{sub 3}, KNO{sub 3}; 0,1M solution of HCl; NaOH solution of different concentration. The method of model radioactive solution was used to find the sorption ability for cesium and cobalt every modified zeolite. The model solution were 0.05M solution of cobalt labelled by {sup 60}Co or cesium labelled by {sup 137}Cs. The highest sorption ability was observed for zeolite modified by NaOH. The influence of pH on uptake of cesium and cobalt by modified zeolite was searched as well. The experimental data (leaching tests, compressive strength measurement and porosity) were measured for the case the Cs and Cs from model water solution and radioactive waste water were up taken on chemically modified zeolite and were subsequently incorporated into cement casts on blast furnace cement slags basis. The leachability was tested in water, in basis solution and in acid solution. The leachability in water and basic solution was negligible, in acid solution it was less than 4% which is inside of value of applied measure method. The compressive strength, porosity and leaching experiment are hopefully and show good mechanical stability and good retention of observed radionuclides in samples exposed in leaching solutions. (J.K.).

  3. Plasma sprayed samarium--cobalt permanent magnets

    International Nuclear Information System (INIS)

    Willson, M.C.; Janowiecki, R.J.

    1975-01-01

    Samarium--cobalt permanent magnets were fabricated by arc plasma spraying. This process involves the injection of relatively coarse powder particles into a high-temperature gas for melting and spraying onto a substrate. The technique is being investigated as an economical method for fabricating cobalt--rare earth magnets for advanced traveling wave tubes and cross-field amplifiers. Plasma spraying permits deposition of material at high rates over large areas with optional direct bonding to the substrate, and offers the ability to fabricate magnets in a variety of shapes and sizes. Isotropic magnets were produced with high coercivity and good reproducibility in magnetic properties. Post-spray thermal treatments were used to enhance the magnetic properties of sprayed deposits. Samarium--cobalt magnets, sprayed from samarium-rich powder and subjected to post-spray heat treatment, displayed energy products in excess of 9 million gauss-oersteds and coercive forces of approximately 6000 oersteds. Bar magnet arrays were constructed by depositing magnets on ceramic substrates. (auth)

  4. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.C.

    1975-01-01

    A process is described for preparing novel sintered cobalt--rare earth intermetallic products which can be magnetized to form permanent magnets having stable improved magnetic properties. A cobalt--rare earth metal alloy is formed having a composition which at sintering temperature falls outside the composition covered by the single Co 5 R intermetallic phase on the rare earth richer side. The alloy contains a major amount of the Co 5 R intermetallic phase and a second solid CoR phase which is richer in rare earth metal content than the Co 5 R phase. The specific cobalt and rare earth metal content of the alloy is substantially the same as that desired in the sintered product. The alloy, in particulate form, is pressed into compacts and sintered to the desired density. The sintered product is comprised of a major amount of the Co 5 R solid intermetallic phase and up to about 35 percent of the product of the second solid CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase

  5. The cobalt radioactive isotopes in environment

    International Nuclear Information System (INIS)

    2007-01-01

    For the year 1993 the total activity released in cobalt is 69 GBq for the whole of nuclear power plants. The part of activity in cobalt for La Hague in 1993 is 8 GBq of 58 Co and 2 GBq of 60 Co. The radioactive isotopes released by nuclear power plants or the reprocessing plant of La Hague under liquid effluents are shared by half between 58 Co and 60 Co. The exposure to sealed sources is the most important risk for the cobalt. The risk of acute exposure can associate a local irradiation of several decades of grays inducing a radiological burns, deep burn to treat in surgery by resection or graft even amputation. A global irradiation of organism for several grays induces an acute irradiation syndrome, often serious. At long term the stochastic effects are represented by leukemia and radio-induced cancers. The increase of probability of their occurrence is 1% by sievert. We must remind that the natural spontaneous probability is 25%. (N.C.)

  6. Hot corrosion of low cobalt alloys

    Science.gov (United States)

    Stearns, C. A.

    1982-01-01

    The hot corrosion attack susceptibility of various alloys as a function of strategic materials content are investigated. Preliminary results were obtained for two commercial alloys, UDIMET 700 and Mar-M 247, that were modified by varying the cobalt content. For both alloys the cobalt content was reduced in steps to zero. Nickel content was increased accordingly to make up for the reduced cobalt but all other constituents were held constant. Wedge bar test samples were produced by casting. The hot corrosion test consisted of cyclically exposing samples to the high velocity flow of combustion products from an air-fuel burner fueled with jet A-1 and seeded with a sodium chloride aqueous solution. The flow velocity was Mach 0.5 and the sodium level was maintained at 0.5 ppm in terms of fuel plus air. The test cycle consisted of holding the test samples at 900 C for 1 hour followed by 3 minutes in which the sample could cool to room temperature in an ambient temperature air stream.

  7. Neutron-neutron probe for uranium exploration

    International Nuclear Information System (INIS)

    Smith, R.C.

    1979-01-01

    A neutron activation probe for assaying the amount of fissionable isotopes in an ore body is described which comprises a casing which is movable through a borehole in the ore body, a neutron source and a number of delayed neutron detectors arranged colinearly in the casing below the neutron source for detecting delayed neutrons

  8. Use of in-core self-powered detectors in the nuclear reactor control system

    International Nuclear Information System (INIS)

    Mitel'man, M.G.; Andreev, L.G.; Batenin, I.V.

    1975-01-01

    The paper describes the results of experiments conducted at the Obninsk atomic power station on the establishment of an integrated system for the control and automatic regulation of the distribution of energy liberation. The pick-ups used for this system are direct-charge detectors with rhodium emitters. The system, which consists of 12 integral DPZ-7 detectors distributed evenly on 2 mutually perpendicular diamaters and 2 assemblies, each containing 4 1n direct-charge detectors, monitors the distribution of neutron flow density according to core height. Increased signals from the detectors were fed into the summation block, in which the outgoing signal was also adjusted. The half-life of the rhodium was calculated and the non-inertia of the entire system ascertained. The total operating time of the system for the automatic control of reactor power is approximately 1 h. The influence of interference was not determined. During the experiment, the power of the reactor remained constant, i.e. its regulation by the direct-charge detectors inside the core was effective. (author)

  9. ZnO nanoneedle/H2O solid-liquid heterojunction-based self-powered ultraviolet detector

    Science.gov (United States)

    2013-01-01

    ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. High photosensitivity, excellent spectral selectivity, and fast photoresponse at zero bias are observed in this UV detector. The self-powered behavior can be well explained by the formation of a space charge layer near the interface of the solid-liquid heterojunction, which results in a built-in potential and makes the solid-liquid heterojunction work in photovoltaic mode. PMID:24103153

  10. Self-Powered UV-Near Infrared Photodetector Based on Reduced Graphene Oxide/n-Si Vertical Heterojunction.

    Science.gov (United States)

    Li, Guanghui; Liu, Lin; Wu, Guan; Chen, Wei; Qin, Sujie; Wang, Yi; Zhang, Ting

    2016-09-01

    A novel self-powered photodetector based on reduced graphene oxide (rGO)/n-Si p-n vertical heterojunction with high sensitivity and fast response time is presented. The photodetector contains a p-n vertical heterojunction between a drop-casted rGO thin film and n-Si. Contacts between the semiconductor layer (rGO, n-Si) and source-drain Ti/Au electrodes allow efficient transfer of photogenerated charge carriers. The self-powered UV-near infrared photodetector shows high sensitivity toward a spectrum of light from 365 to 1200 nm. Under the 600 nm illumination (0.81 mW cm -2 ), the device has a photoresponsivity of 1.52 A W -1 , with fast response and recover time (2 ms and 3.7 ms), and the ON/OFF ratios exceed 10 4 when the power density reaches ≈2.5 mW cm -2 . The high photoresponse primarily arises from the built-in electric field formed at the interface of n-Si and rGO film. The effect of rGO thickness, rGO reduction level, and layout of rGO/n-Si effective contact area on device performance are also systematically investigated. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Direct detection of cysteine using functionalized BaTiO3 nanoparticles film based self-powered biosensor.

    Science.gov (United States)

    Selvarajan, Sophia; Alluri, Nagamalleswara Rao; Chandrasekhar, Arunkumar; Kim, Sang-Jae

    2017-05-15

    Simple, novel, and direct detection of clinically important biomolecules have continuous demand among scientific community as well as in market. Here, we report the first direct detection and facile fabrication of a cysteine-responsive, film-based, self-powered device. NH 2 functionalized BaTiO 3 nanoparticles (BT-NH 2 NPs) suspended in a three-dimensional matrix of an agarose (Ag) film, were used for cysteine detection. BaTiO 3 nanoparticles (BT NPs) semiconducting as well as piezoelectric properties were harnessed in this study. The changes in surface charge properties of the film with respect to cysteine concentrations were determined using a current-voltage (I-V) technique. The current response increased with cysteine concentration (linear concentration range=10µM-1mM). Based on the properties of the composite (BT/Ag), we created a self-powered cysteine sensor in which the output voltage from a piezoelectric nanogenerator was used to drive the sensor. The potential drop across the sensor was measured as a function of cysteine concentrations. Real-time analysis of sensor performance was carried out on urine samples by non-invasive method. This novel sensor demonstrated good selectivity, linear concentration range and detection limit of 10µM; acceptable for routine analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Pt/ZnO nanoarray nanogenerator as self-powered active gas sensor with linear ethanol sensing at room temperature.

    Science.gov (United States)

    Zhao, Yayu; Lai, Xuan; Deng, Ping; Nie, Yuxin; Zhang, Yan; Xing, Lili; Xue, Xinyu

    2014-03-21

    A self-powered gas sensor that can actively detect ethanol at room temperature has been realized from a Pt/ZnO nanoarray nanogenerator. Pt nanoparticles are uniformly distributed on the whole surface of ZnO nanowires. The piezoelectric output of Pt/ZnO nanoarrays can act not only as a power source, but also as a response signal to ethanol at room temperature. Upon exposure to dry air and 1500 ppm ethanol at room temperature, the piezoelectric output of the device under the same compressive strain is 0.672 and 0.419 V, respectively. Moreover, a linear dependence of the sensitivity on the ethanol concentration is observed. Such a linear ethanol sensing at room temperature can be attributed to the atmosphere-dependent variety of the screen effect on the piezoelectric output of ZnO nanowires, the catalytic properties of Pt nanoparticles, and the Schottky barriers at Pt/ZnO interfaces. The present results can stimulate research in the direction of designing new material systems for self-powered room-temperature gas sensing.

  13. A 3D paper-based enzymatic fuel cell for self-powered, low-cost glucose monitoring.

    Science.gov (United States)

    Fischer, Christopher; Fraiwan, Arwa; Choi, Seokheun

    2016-05-15

    In this work, we demonstrate a novel low-cost, self-powered paper-based biosensor for glucose monitoring. The device operating mechanism is based on a glucose/oxygen enzymatic fuel cell using an electrochemical energy conversion as a transducing element for glucose monitoring. The self-powered glucose biosensor features (i) a 3D origami paper-based structure for easy system integration onto paper, (ii) an air-cathode on paper for low-cost production and easy operation, and (iii) a screen printed chitosan/glucose oxidase anode for stable current generation as an analytical signal for glucose monitoring. The sensor showed a linear range of output current at 1-5mM glucose (R(2)=0.996) with a sensitivity of 0.02 µA mM(-1). The advantages offered by such a device, including a low cost, lack of external power sources/sophisticated external transducers, and the capacity to rapidly generate reliable results, are well suited for the clinical and social settings of the developing world. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Self-Powered, Flexible, and Solution-Processable Perovskite Photodetector Based on Low-Cost Carbon Cloth.

    Science.gov (United States)

    Sun, Haoxuan; Lei, Tianyu; Tian, Wei; Cao, Fengren; Xiong, Jie; Li, Liang

    2017-07-01

    Flexible perovskite photodetectors are usually constructed on indium-tin-oxide-coated polymer substrates, which are expensive, fragile, and not resistant to high temperature. Herein, for the first time, a high-performance flexible perovskite photodetector is fabricated based on low-cost carbon cloth via a facile solution processable strategy. In this device, perovskite microcrystal and Spiro-OMeTAD (hole transporting material) blended film act as active materials for light detection, and carbon cloth serves as both a flexible substrate and a conductive electrode. The as-fabricated photodetector shows a broad spectrum response from ultraviolet to near-infrared light, high responsivity, fast response speed, long-term stability, and self-powered capability. Flexible devices show negligible degradation after several tens of bending cycles and at the extremely bending angle of 180°. This work promises a new technique to construct flexible, high-performance photodetectors with low cost and self-powered capability. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 3D Orthogonal Woven Triboelectric Nanogenerator for Effective Biomechanical Energy Harvesting and as Self-Powered Active Motion Sensors.

    Science.gov (United States)

    Dong, Kai; Deng, Jianan; Zi, Yunlong; Wang, Yi-Cheng; Xu, Cheng; Zou, Haiyang; Ding, Wenbo; Dai, Yejing; Gu, Bohong; Sun, Baozhong; Wang, Zhong Lin

    2017-10-01

    The development of wearable and large-area energy-harvesting textiles has received intensive attention due to their promising applications in next-generation wearable functional electronics. However, the limited power outputs of conventional textiles have largely hindered their development. Here, in combination with the stainless steel/polyester fiber blended yarn, the polydimethylsiloxane-coated energy-harvesting yarn, and nonconductive binding yarn, a high-power-output textile triboelectric nanogenerator (TENG) with 3D orthogonal woven structure is developed for effective biomechanical energy harvesting and active motion signal tracking. Based on the advanced 3D structural design, the maximum peak power density of 3D textile can reach 263.36 mW m -2 under the tapping frequency of 3 Hz, which is several times more than that of conventional 2D textile TENGs. Besides, its collected power is capable of lighting up a warning indicator, sustainably charging a commercial capacitor, and powering a smart watch. The 3D textile TENG can also be used as a self-powered active motion sensor to constantly monitor the movement signals of human body. Furthermore, a smart dancing blanket is designed to simultaneously convert biomechanical energy and perceive body movement. This work provides a new direction for multifunctional self-powered textiles with potential applications in wearable electronics, home security, and personalized healthcare. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Measurement for cobalt target activity and its axial distribution

    International Nuclear Information System (INIS)

    Li Xingyuan; Chen Zigen.

    1985-01-01

    Cobalt target activity and its axial distribution are measured in process of producing radioactive isotopes 60 Co by irradiation in HFETR. Cobalt target activity is obtained with measured data at 3.60 m and 4.60 m, relative axial distribution of cobalt target activity is obtained with one at 30 cm, and axial distribution of cobalt target activity(or specific activity) is obtained with both of data. The difference between this specific activity and measured result for 60 Co teletherapy sources in the end is less than +- 5%

  17. Cobalt metabolism and toxicology—A brief update

    International Nuclear Information System (INIS)

    Simonsen, Lars Ole; Harbak, Henrik; Bennekou, Poul

    2012-01-01

    Cobalt metabolism and toxicology are summarized. The biological functions of cobalt are updated in the light of recent understanding of cobalt interference with the sensing in almost all animal cells of oxygen deficiency (hypoxia). Cobalt (Co 2+ ) stabilizes the transcriptional activator hypoxia-inducible factor (HIF) and thus mimics hypoxia and stimulates erythropoietin (Epo) production, but probably also by the same mechanism induces a coordinated up-regulation of a number of adaptive responses to hypoxia, many with potential carcinogenic effects. This means on the other hand that cobalt (Co 2+ ) also may have beneficial effects under conditions of tissue hypoxia, and possibly can represent an alternative to hypoxic preconditioning. Cobalt is acutely toxic in larger doses, and in mammalian in vitro test systems cobalt ions and cobalt metal are cytotoxic and induce apoptosis and at higher concentrations necrosis with inflammatory response. Cobalt metal and salts are also genotoxic, mainly caused by oxidative DNA damage by reactive oxygen species, perhaps combined with inhibition of DNA repair. Of note, the evidence for carcinogenicity of cobalt metal and cobalt sulfate is considered sufficient in experimental animals, but is as yet considered inadequate in humans. Interestingly, some of the toxic effects of cobalt (Co 2+ ) have recently been proposed to be due to putative inhibition of Ca 2+ entry and Ca 2+ -signaling and competition with Ca 2+ for intracellular Ca 2+ -binding proteins. The tissue partitioning of cobalt (Co 2+ ) and its time-dependence after administration of a single dose have been studied in man, but mainly in laboratory animals. Cobalt is accumulated primarily in liver, kidney, pancreas, and heart, with the relative content in skeleton and skeletal muscle increasing with time after cobalt administration. In man the renal excretion is initially rapid but decreasing over the first days, followed by a second, slow phase lasting several weeks, and

  18. Pharmacokinetics of inorganic cobalt and a vitamin B12 supplement in the Thoroughbred horse: Differentiating cobalt abuse from supplementation.

    Science.gov (United States)

    Hillyer, L L; Ridd, Z; Fenwick, S; Hincks, P; Paine, S W

    2018-05-01

    While cobalt is an essential micronutrient for vitamin B 12 synthesis in the horse, at supraphysiological concentrations, it has been shown to enhance performance in human subjects and rats, and there is evidence that its administration in high doses to horses poses a welfare threat. Animal sport regulators currently control cobalt abuse via international race day thresholds, but this work was initiated to explore means of potentially adding to application of those thresholds since cobalt may be present in physiological concentrations. To devise a scientific basis for differentiation between presence of cobalt from bona fide supplementation and cobalt doping through the use of ratios. Six Thoroughbred horses were given 10 mL vitamin B 12 /cobalt supplement (Hemo-15 ® ; Vetoquinol, Buckingham, Buckinghamshire, UK., 1.5 mg B 12 , 7 mg cobalt gluconate = 983 μg total Co) as an i.v. bolus then an i.v. infusion (15 min) of 100 mg cobalt chloride (45.39 mg Co) 6 weeks later. Pre-and post-administration plasma and urine samples were analysed for cobalt and vitamin B 12 . Urine and plasma samples were analysed for vitamin B 12 using an immunoassay and cobalt concentrations were measured via ICP-MS. Baseline concentrations of cobalt in urine and plasma for each horse were subtracted from their cobalt concentrations post-administration for the PK analysis. Compartmental analysis was used for the determination of plasma PK parameters for cobalt using commercially available software. On administration of a vitamin B 12 /cobalt supplement, the ratio of cobalt to vitamin B 12 in plasma rapidly increased to approximately 3 and then rapidly declined below a ratio of 1 and then back to near baseline over the next week. On administration of 100 mg cobalt chloride, the ratio initially exceeded 10 in plasma and then declined with the lower 95% confidence interval remaining above a ratio of 1 for 7 days. For two horses with extended sampling, the plasma ratio remained above one for

  19. Structural study of layered cobaltate La.sub.x/3./sub.CoO.sub.2./sub. (x ~ 1) at temperatures up to 800 K

    Czech Academy of Sciences Publication Activity Database

    Knížek, Karel; Jirák, Zdeněk; Hejtmánek, Jiří; Brázda, Petr; Buršík, Josef; Soroka, Miroslav; Beran, Přemysl

    2015-01-01

    Roč. 229, Sep (2015), 160-163 ISSN 0022-4596 R&D Projects: GA ČR GA13-03708S; GA MŠk LM2011019 Institutional support: RVO:68378271 ; RVO:61388980 ; RVO:61389005 Keywords : cobaltates * thermoelectrics * neutron diffraction * structure * La x/3 CoO 2 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.265, year: 2015

  20. A novel method to synthesize cobalt oxide (Co3O4) nanowires from cobalt (Co) nanobowls

    DEFF Research Database (Denmark)

    Srivastava, Akhilesh Kumar; Madhavi, S.; Ramanujan, R.V.

    2010-01-01

    A novel method suitable for the synthesis of the cobalt oxide (Co3O4) nanowires at targeted regions is presented in this report. Cobalt (Co) nanobowls synthesized by colloidal crystal directed assembly were transformed into Co3O4 nanowires by a simple heat treatment process. Co nanobowls exhibited...... a two phase (h.c.p. + f.c.c.) microstructure while single phase microstructure was observed for Co3O4 nanowires. Ferromagnetic Co nanobowls showed a dependence of coercivity on bowl size while Co3O4 exhibited weak ferromagnetic behavior....

  1. Measurements and analysis of neutron and gamma noise in BWR's

    International Nuclear Information System (INIS)

    Dam, H. van; Kleiss, E.B.J.

    1985-01-01

    Neutron and gamma sensitive collectrons (self-powered detectors) have been designed for incore noise measurements in BWRs. A so-called twin-type has been developed for measurements of two-phase flow characteristics and detailed axial velocity distributions. Construction aspects of the twin detectors are discussed. An analysis is presented of the response of both detector types to incore parametric fluctuations. This analysis is based on detector response functions which provide an insight into the 'field of view' of the two types. The results are supported by experimental verifications; it is shown that incore gamma detectors provide useful additional information about two-phase flow in a BWR. (author)

  2. Study of complex formation of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel

    International Nuclear Information System (INIS)

    Ismailova, M.M.; Egorova, L.A.; Khamidov, B.O.

    1993-01-01

    Present article is devoted to study of complex formation of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel. The condition of cobalt in various rate of oxidation in acrylamide aqueous solutions was studied. The concentration conditions of stability of system Co(II)-Co(III) were defined. The composition of coordination compounds of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel was determined.

  3. Measurement of thermal, epithermal and fast neutron flux in the IEA-R1 reactor by the foil activation method

    International Nuclear Information System (INIS)

    Koskinas, M.F.

    1979-01-01

    Experimental and theoretical details of the foil activation method applied to neutrons flux measurements at the IEA-R1 reactor are presented. The thermal - and epithermal - neutron flux were determined form activation measurements of gold, cobalt and manganese foils; and for the fast neutron flux determination, aluminum, iron and nickel foils were used. The measurements of the activity induced in the metal foils were performed using a Ge-Li gamma spectrometry system. In each energy range of the reactor neutron spectrum, the agreement among the experimental flux values obtained using the three kind of materials, indicates the consistency of the theoretical approach and of the nuclear parameters selected. (Author) [pt

  4. neutron radiography

    International Nuclear Information System (INIS)

    Barton, J.P.

    1993-01-01

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

  5. NEUTRONIC REACTOR

    Science.gov (United States)

    Wigner, E.P.; Weinberg, A.W.; Young, G.J.

    1958-04-15

    A nuclear reactor which uses uranium in the form of elongated tubes as fuel elements and liquid as a coolant is described. Elongated tubular uranium bodies are vertically disposed in an efficient neutron slowing agent, such as graphite, for example, to form a lattice structure which is disposed between upper and lower coolant tanks. Fluid coolant tubes extend through the uranium bodies and communicate with the upper and lower tanks and serve to convey the coolant through the uranium body. The reactor is also provided with means for circulating the cooling fluid through the coolant tanks and coolant tubes, suitable neutron and gnmma ray shields, and control means.

  6. Neutron dosimeter

    International Nuclear Information System (INIS)

    Bartko, J.; Schoch, K.F. Jr.; Congedo, T.V.; Anderson, S.L. Jr.

    1989-01-01

    This patent describes a nuclear reactor. It comprises a reactor core; a thermal shield surrounding the reactor core; a pressure vessel surrounding the thermal shield; a neutron dosimeter positioned outside of the thermal shield, the neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and means, outside the pressure vessel and electrically connected to the layer of second material, for measuring electrical conductivity of the layer of second material

  7. Dosing of anaerobic granular sludge bioreactors with cobalt: Impact of cobalt retention on methanogenic activity

    KAUST Repository

    Fermoso, Fernando G.

    2010-12-01

    The effect of dosing a metal limited anaerobic sludge blanket (UASB) reactor with a metal pulse on the methanogenic activity of granular sludge has thus far not been successfully modeled. The prediction of this effect is crucial in order to optimize the strategy for metal dosage and to prevent unnecessary losses of resources. This paper describes the relation between the initial immobilization of cobalt in anaerobic granular sludge cobalt dosage into the reactor and the evolution of methanogenic activity during the subsequent weeks. An operationally defined parameter (A0· B0) was found to combine the amount of cobalt immobilized instantaneously upon the pulse (B0) and the amount of cobalt immobilized within the subsequent 24. h (A0). In contrast with the individual parameters A0 and B0, the parameter A0· B0 correlated significantly with the methanogenic activity of the sludge during the subsequent 16 or 35. days. This correlation between metal retention and activity evolution is a useful tool to implement trace metal dosing strategies for biofilm-based biotechnological processes. © 2010.

  8. Cobalt(I) and Cobalt(III) Cyclopentadienyl Complexes with New Silicon-branched Fluorous Tags

    Czech Academy of Sciences Publication Activity Database

    Strašák, Tomáš; Čermák, Jan; Červenková Šťastná, Lucie; Sýkora, Jan; Fajgar, Radek

    2014-01-01

    Roč. 159, MAR 2014 (2014), s. 15-20 ISSN 0022-1139 R&D Projects: GA ČR(CZ) GAP106/12/1372 Institutional support: RVO:67985858 Keywords : fluorous tag * cobalt complex * cyclopentadienyl complex Subject RIV: CC - Organic Chemistry Impact factor: 1.948, year: 2014

  9. Combined analysis of neutron and photon flux measurements for the Jules Horowitz reactor core mapping

    Energy Technology Data Exchange (ETDEWEB)

    Fourmentel, D.; Villard, J. F.; Lyoussi, A. [DEN Reactor Studies Dept., French Nuclear Energy and Alternative Energies Commission, CEA Cadarache, 13108 Saint Paul-Lez-Durance (France); Reynard-Carette, C. [Laboratoire Chimie Provence LCP UMR 6264, Univ. of Provence, Centre St. Jerome, 13397 Marseille Cedex 20 (France); Bignan, G.; Chauvin, J. P.; Gonnier, C.; Guimbal, P.; Malo, J. Y. [DEN Reactor Studies Dept., French Nuclear Energy and Alternative Energies Commission, CEA Cadarache, 13108 Saint Paul-Lez-Durance (France); Carette, M.; Janulyte, A.; Merroun, O.; Brun, J.; Zerega, Y.; Andre, J. [Laboratoire Chimie Provence LCP UMR 6264, Univ. of Provence, Centre St. Jerome, 13397 Marseille Cedex 20 (France)

    2011-07-01

    We study the combined analysis of nuclear measurements to improve the knowledge of the irradiation conditions in the experimental locations of the future Jules Horowitz Reactor (JHR). The goal of the present work is to measure more accurately neutron flux, photon flux and nuclear heating in the reactor. In a Material Testing Reactor (MTR), nuclear heating is a crucial parameter to design the experimental devices to be irradiated in harsh nuclear conditions. This parameter drives the temperature of the devices and of the samples. The numerical codes can predict this parameter but in-situ measurements are necessary to reach the expected accuracy. For this reason, one objective of the IN-CORE program [1] is to study the combined measurements of neutron and photon flux and their cross advanced interpretation. It should be reminded that both neutron and photon sensors are not totally selective as their signals are due to neutron and photon interactions. We intend to measure the neutron flux by three different kinds of sensors (Uranium Fission chamber, Plutonium Fission chamber and Self Powered Neutron Detector), the photon flux by two different sensors (Ionization chamber and Self Powered Gamma Detector) and the nuclear heating by two different ones (Differential calorimeter and Gamma Thermometer). For the same parameter, we expect that the use of different kinds of sensors will allow a better estimation of the aimed parameter by mixing different spectrum responses and different neutron and gamma contributions. An experimental test called CARMEN-1 is scheduled in OSIRIS reactor (CEA Saclay - France) at the end of 2011, with the goal to map irradiation locations in the reactor reflector to get a first validation of the analysis model. This article focuses on the sensor selection for CARMEN-1 experiment and to the way to link neutron and photon flux measurements in view to reduce their uncertainties but also to better assess the neutron and photon contributions to nuclear

  10. Combined analysis of neutron and photon flux measurements for the Jules Horowitz reactor core mapping

    International Nuclear Information System (INIS)

    Fourmentel, D.; Villard, J. F.; Lyoussi, A.; Reynard-Carette, C.; Bignan, G.; Chauvin, J. P.; Gonnier, C.; Guimbal, P.; Malo, J. Y.; Carette, M.; Janulyte, A.; Merroun, O.; Brun, J.; Zerega, Y.; Andre, J.

    2011-01-01

    We study the combined analysis of nuclear measurements to improve the knowledge of the irradiation conditions in the experimental locations of the future Jules Horowitz Reactor (JHR). The goal of the present work is to measure more accurately neutron flux, photon flux and nuclear heating in the reactor. In a Material Testing Reactor (MTR), nuclear heating is a crucial parameter to design the experimental devices to be irradiated in harsh nuclear conditions. This parameter drives the temperature of the devices and of the samples. The numerical codes can predict this parameter but in-situ measurements are necessary to reach the expected accuracy. For this reason, one objective of the IN-CORE program [1] is to study the combined measurements of neutron and photon flux and their cross advanced interpretation. It should be reminded that both neutron and photon sensors are not totally selective as their signals are due to neutron and photon interactions. We intend to measure the neutron flux by three different kinds of sensors (Uranium Fission chamber, Plutonium Fission chamber and Self Powered Neutron Detector), the photon flux by two different sensors (Ionization chamber and Self Powered Gamma Detector) and the nuclear heating by two different ones (Differential calorimeter and Gamma Thermometer). For the same parameter, we expect that the use of different kinds of sensors will allow a better estimation of the aimed parameter by mixing different spectrum responses and different neutron and gamma contributions. An experimental test called CARMEN-1 is scheduled in OSIRIS reactor (CEA Saclay - France) at the end of 2011, with the goal to map irradiation locations in the reactor reflector to get a first validation of the analysis model. This article focuses on the sensor selection for CARMEN-1 experiment and to the way to link neutron and photon flux measurements in view to reduce their uncertainties but also to better assess the neutron and photon contributions to nuclear

  11. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  12. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  13. 21 CFR 189.120 - Cobaltous salts and its derivatives.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Cobaltous salts and its derivatives. 189.120 Section 189.120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... malt beverages as a foam stabilizer and to prevent “gushing.” (b) Food containing any added cobaltous...

  14. Study to use graded cobalt adjuster in 540 MWe PHWR

    International Nuclear Information System (INIS)

    Raj, Manish; Fernando, M.P.S.; Pradhan, A.S.; Kumar, A.N.

    2007-01-01

    Full text: There are 17 adjusters in 540 MWe PHWR, which are essentially provided for xenon override function. They also provide flux flattening being in the central region of the reactor core. The present design of adjusters consists of stainless steel tube. The adjuster rods are grouped into 8 banks for movement. Since adjusters are normally fully inserted during reactor operation, they are best suited for production of cobalt 60. The nickel-plated cobalt in the form of either slugs or pellet are used for the design of cobalt pencils. The number of pencils can be varied to optimize the reactivity load and cobalt 60 production requirement. The worth and activity of cobalt adjusters have been worked out considering different pin configuration for the adjuster assembly. To start with we have assumed all adjusters throughout its length are of the same configuration. The flux depression factors within the cobalt pencils have been considered in the estimations of the specific and total cobalt 60 activities. The option of using graded cobalt adjusters, where different pin configuration along the length is considered for better flux flattening

  15. Removal of Cobalt Ions by Precipitate Foam Flotation

    Energy Technology Data Exchange (ETDEWEB)

    Jung, In Ha; Lee, Jung Won [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-09-30

    Simulated waste liquid containing 50 ppm cobalt ion was tested by precipitate flotation using a sodium lauryl sulfate as a collector. The effects of initial cobalt ion concentration, pH, surfactant concentration, flotation time, gas flow rate and foreign ions on removal efficiency of cobalt ion were studied. Pretreatment of the waste liquid with 35% H{sub 2}O{sub 2} prior to precipitate flotation made shift of optimal flotation pH from the strong alkalinity to weak alkaline range and made a favorable flotation of cobalt ion in wide range of pH. For the result of this experiment, 99.8% removal efficiency was obtained on the conditions of initial cobalt ion concentration 50 ppm, pH 9.5, gas flow rate 70 ml/min, flotation time 30 min. The simulate ion was formed to be the most harmful ion against removal of cobalt by precipitate flotation of the species which were tested. The presence of 0.1 M of SO{sub 4}{sup 2-} ion decreased removal efficiency of cobalt to 90% while the cobalt were almost entirely removed in the absence of sulfate ion. (author). 11 refs., 8 figs.

  16. Adsorption Study of Cobalt on Treated Granular Activated Carbon

    OpenAIRE

    Y. V. Hete; S. B. Gholase; R. U. Khope

    2012-01-01

    This study is carried out for the removal of cobalt from aqueous solution using granular activated carbon in combination with p-nitro benzoic acid at temperature 25±1 °C. The adsorption isotherm of cobalt on granular activated carbon has been determined and the data fitted reasonably well to the Langmuir and Freundlich isotherm for activated carbon.

  17. Adsorption Study of Cobalt on Treated Granular Activated Carbon

    Directory of Open Access Journals (Sweden)

    Y. V. Hete

    2012-01-01

    Full Text Available This study is carried out for the removal of cobalt from aqueous solution using granular activated carbon in combination with p-nitro benzoic acid at temperature 25±1 °C. The adsorption isotherm of cobalt on granular activated carbon has been determined and the data fitted reasonably well to the Langmuir and Freundlich isotherm for activated carbon.

  18. Microwave Mapping Demonstration Using the Thermochromic Cobalt Chloride Equilibrium

    Science.gov (United States)

    Nguyen, Vu D.; Birdwhistell, Kurt R.

    2014-01-01

    An update to the thermochromic cobalt(II) chloride equilibrium demonstration is described. Filter paper that has been saturated with aqueous cobalt(II) chloride is heated for seconds in a microwave oven, producing a color change. The resulting pink and blue map is used to colorfully demonstrate Le Châtelier's principle and to illuminate the…

  19. The role of cobalt on the creep of Waspaloy

    Science.gov (United States)

    Jarrett, R. N.; Chin, L.; Tien, J. K.

    1984-01-01

    Cobalt was systematically replaced with nickel in Waspaloy (which normally contains 13% Co) to determine the effects of cobalt on the creep behavior of this alloy. Effects of cobalt were found to be minimal on tensile strengths and microstructure. The creep resistance and the stress rupture resistance determined in the range from 704 to 760 C (1300 to 1400 C) were found to decrease as cobalt was removed from the standard alloy at all stresses and temperatures. Roughly a ten-fold drop in rupture life and a corresponding increase in minimum creep rate were found under all test conditions. Both the apparent creep activation energy and the matrix contribution to creep resistance were found to increase with cobalt. These creep effects are attributed to cobalt lowering the stacking fault energy of the alloy matrix. The creep resistance loss due to the removal of cobalt is shown to be restored by slightly increasing the gamma' volume fraction. Results are compared to a previous study on Udimet 700, a higher strength, higher gamma' volume fraction alloy with similar phase chemistry, in which cobalt did not affect creep resistance. An explanation for this difference in behavior based on interparticle spacing and cross-slip is presented.

  20. Potential for cobalt recovery from lateritic ores in Europe

    Science.gov (United States)

    Herrington, R.

    2012-04-01

    Cobalt is one of the 'critical metals' identified under the EU Raw Materials Initiative. Annually the global mine production of cobalt is around 55,000 tonnes,with Europe's industries consuming around 30% of that figure. Currently Europe produces around 27 tonnes of cobalt from mines in Finland although new capacity is planned. Co-bearing nickel laterite ores being mined in Greece, Macedonia and Kosovo where the cobalt is currently not being recovered (ores have typical analyses of 0.055% Co and >1% Ni,). These ores are currently treated directly in pyrometallurgical plants to recover the contained nickel and this process means there is no separate cobalt product produced. Hydrometallurgical treatment of mineralogically suitable laterite ores can recover the cobalt; for example Cuba recovers 3,500 tonnes of cobalt from its laterite mining operations, which are of a similar scale to the current European operations. Implementation of hydrometallurgical techniques is in its infancy in Europe with one deposit in Turkey planning to use atmospheric heap leaching to recover nickel and copper from oxide-dominated ores. More widespread implementation of these methods to mineralogically suitable ore types could unlock the highly significant undeveloped resources (with metal contents >0.04% Co and >1% Ni), which have been defined throughout the Balkans eastwards into Turkey. At a conservative estimate, this region has the potential to supply up to 30% of the EU cobalt requirements.

  1. Highly selective cobalt-catalyzed hydrovinylation of styrene

    NARCIS (Netherlands)

    Grutters, M.M.P.; Müller, C.; Vogt, D.

    2006-01-01

    The hydrovinylation reaction is a codimerization of a 1,3-diene or vinyl arene and ethene with great potential for fine chemicals and pharmaceuticals. For the first time, enantioselective cobalt-catalyzed hydrovinylations of styrene were achieved with a cobalt-based system bearing a chiral

  2. A monocrystal of 59Co as a nuclear orientation thermometer in neutron experiments with oriented targets

    International Nuclear Information System (INIS)

    Fasoli, U.; Galeazzi, G.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.

    1980-01-01

    An apparatus for measuring temperatures in the millikelvin region is described based on the 'deformation effect' on fast neutron transmission through an aligned 59 Co monocrystal, employing a 252 Cf pill as the neutron source. A statistical accuracy of a few percent in a few minutes is obtainable with a heat input of some tens of pW. The apparatus is suitable in neutron experiments with oriented targets when the gamma-ray background hinders the use of gamma-ray anisotropy thermometers. In these and similar cases, in which the temperature must be held constant for long periods, the large heat capacity of the cobalt sample is not a drawback. (orig.)

  3. Cobalt ferrite nanoparticles under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Saccone, F. D.; Ferrari, S.; Grinblat, F.; Bilovol, V. [Instituto de Tecnologías y Ciencias de la Ingeniería, “Ing. H. Fernández Long,” Av. Paseo Colón 850 (1063), Buenos Aires (Argentina); Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Fisica Aplicada, Institut Universitari de Ciència dels Materials, Universitat de Valencia, c/ Doctor Moliner 50, E-46100 Burjassot, Valencia (Spain); Agouram, S. [Departamento de Física Aplicada y Electromagnetismo, Universitat de València, 46100 Burjassot, Valencia (Spain)

    2015-08-21

    We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20–27 GPa to 7.5–12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B{sub 0} = 204 GPa) is considerably larger than the value previously reported for bulk CoFe{sub 2}O{sub 4} (B{sub 0} = 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B{sub 0} = 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible.

  4. Cobalt60 plaques in recurrent retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Fass, D.; McCormick, B.; Abramson, D.; Ellsworth, R. (Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, NY, NY (USA))

    1991-08-01

    Cobalt60 plaque irradiation is one treatment option for patients with recurrent retinoblastoma following conventional external beam irradiation (ERT). Tumorocidal doses can be delivered without excessive risk of normal tissue injury. In patients not considered candidates for xenon arc or cryotherapy, 60Co is an alternative to enucleation. Between 1968 and 1987, 85 patients were treated with 60Co plaques, 72 of whom had failed prior ERT. Age at diagnosis ranged from 1 week to 4 years. There are 37 males and 35 females. Seventy-one patients had bilateral disease and one had unilateral. Three patients had both eyes plaqued. Prior ERT ranged from 30 to 70 Gy (mean 4200 Gy). Time from initial therapy to failure ranged from 13 to 60 months. Cobalt plaques of 10 mm, 15 mm, or 10 {times} 15 mm were used depending on tumor size and location. Dose prescribed to the apex of the tumor ranged from 30 to 50 Gy (median 40 Gy) given over 3 to 8 days. Twelve patients had two plaque applications; three patients had three plaque applications. All patients were followed with routine ophthalmoscopic examinations. Follow-up ranged from 2 to 22 years (mean 8.7). Seven patients died of metastatic disease; 10 patients developed non-ocular second tumors. Thirty patients required enucleation. Twenty-two patients had clear tumor progression, two patients had radiation complications, and six patients had a combination of tumor growth and complications. Cobalt60 can salvage eyes in retinoblastoma patients failing ERT. Currently, the authors are using I125 in an attempt to spare normal ocular tissue and reduce subsequent complications.

  5. Cobalt60 plaques in recurrent retinoblastoma

    International Nuclear Information System (INIS)

    Fass, D.; McCormick, B.; Abramson, D.; Ellsworth, R.

    1991-01-01

    Cobalt60 plaque irradiation is one treatment option for patients with recurrent retinoblastoma following conventional external beam irradiation (ERT). Tumorocidal doses can be delivered without excessive risk of normal tissue injury. In patients not considered candidates for xenon arc or cryotherapy, 60Co is an alternative to enucleation. Between 1968 and 1987, 85 patients were treated with 60Co plaques, 72 of whom had failed prior ERT. Age at diagnosis ranged from 1 week to 4 years. There are 37 males and 35 females. Seventy-one patients had bilateral disease and one had unilateral. Three patients had both eyes plaqued. Prior ERT ranged from 30 to 70 Gy (mean 4200 Gy). Time from initial therapy to failure ranged from 13 to 60 months. Cobalt plaques of 10 mm, 15 mm, or 10 x 15 mm were used depending on tumor size and location. Dose prescribed to the apex of the tumor ranged from 30 to 50 Gy (median 40 Gy) given over 3 to 8 days. Twelve patients had two plaque applications; three patients had three plaque applications. All patients were followed with routine ophthalmoscopic examinations. Follow-up ranged from 2 to 22 years (mean 8.7). Seven patients died of metastatic disease; 10 patients developed non-ocular second tumors. Thirty patients required enucleation. Twenty-two patients had clear tumor progression, two patients had radiation complications, and six patients had a combination of tumor growth and complications. Cobalt60 can salvage eyes in retinoblastoma patients failing ERT. Currently, the authors are using I125 in an attempt to spare normal ocular tissue and reduce subsequent complications

  6. ZnO nanotube-based dye-sensitized solar cell and its application in self-powered devices

    Energy Technology Data Exchange (ETDEWEB)

    Han Jingbin; Fan Fengru; Xu Chen; Lin Shisheng; Wang Zhonglin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States); Wei Min; Duan Xue, E-mail: zhong.wang@mse.gatech.edu, E-mail: weimin@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2010-10-08

    High-density vertically aligned ZnO nanotube arrays were fabricated on FTO substrates by a simple and facile chemical etching process from electrodeposited ZnO nanorods. The nanotube formation was rationalized in terms of selective dissolution of the (001) polar face. The morphology of the nanotubes can be readily controlled by electrodeposition parameters for the nanorod precursor. By employing the 5.1 {mu}m-length nanotubes as the photoanode for a dye-sensitized solar cell (DSSC), a full-sun conversion efficiency of 1.18% was achieved. Furthermore, we show that the DSSC unit can serve as a robust power source to drive a humidity sensor, with a potential for self-powered devices.

  7. Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

    Directory of Open Access Journals (Sweden)

    Md Rezaul Hasan

    2015-10-01

    Full Text Available A self-powered ultraviolet (UV photodetector (PD based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO coated plastic polyethylene terephthalate (PET substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

  8. Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Md Rezaul [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030 (United States); Xie, Ting; Liu, Guannan [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742 (United States); Barron, Sara C. [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Nguyen, Nhan V. [Semiconductor and Dimensional Metrology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Motayed, Abhishek [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Rao, Mulpuri V. [Department of Electrical and Computer Engineering, George Mason University, 4400 University Drive, Fairfax, Virginia 22030 (United States); Debnath, Ratan, E-mail: ratan.debnath@nist.gov [Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2015-10-01

    A self-powered ultraviolet (UV) photodetector (PD) based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO) coated plastic polyethylene terephthalate (PET) substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

  9. A self-powered nano-photodetector based on PFH/ZnO nanorods organic/inorganic heterojunction

    Science.gov (United States)

    Li, Xiaoyun; Liu, Wei; Li, Peigang; Song, Jia; An, Yuehua; Shen, Jingqin; Wang, Shunli; Guo, Daoyou

    2018-03-01

    PFH/ZnO nanorods heterojunctions were fabricated by spin-coating p-type Poly (9,9-dihexylfluorene) (PFH) on n-type vertically aligned ZnO nanorod arrays grown by a facile hydrothermal method on indium tin oxide (ITO) transparent conductive glass. A typical p-n junction behavior was observed in the fabricated heterojunction. The current of heterojunction increases and decreases dramatically by switching the illumination on and off at zero bias, showing potential self-powered photodetector applications. The heterojunction were capable of generating negative current when illuminated under an appropriate wavelength. The photoresponse properties of the heterojunction can be tuned by the applied bias. In vacuum, the rectifying behavior disappeared, and show only simple semiconductor behavior. Band structure of the heterojunction was schematic drawn and explain the mechanism of the properties of PFH/ZnO nanorods heterojunctions.

  10. Self-Powered Implantable Skin-Like Glucometer for Real-Time Detection of Blood Glucose Level In Vivo

    Science.gov (United States)

    Zhang, Wanglinhan; Zhang, Linlin; Gao, Huiling; Yang, Wenyan; Wang, Shuai; Xing, Lili; Xue, Xinyu

    2018-06-01

    Implantable bioelectronics for analyzing physiological biomarkers has recently been recognized as a promising technique in medical treatment or diagnostics. In this study, we developed a self-powered implantable skin-like glucometer for real-time detection of blood glucose level in vivo. Based on the piezo-enzymatic-reaction coupling effect of GOx@ZnO nanowire, the device under an applied deformation can actively output piezoelectric signal containing the glucose-detecting information. No external electricity power source or battery is needed for this device, and the outputting piezoelectric voltage acts as both the biosensing signal and electricity power. A practical application of the skin-like glucometer implanted in mouse body for detecting blood glucose level has been simply demonstrated. These results provide a new technique path for diabetes prophylaxis and treatment.

  11. Adaptable piezoelectric hemispherical composite strips using a scalable groove technique for a self-powered muscle monitoring system.

    Science.gov (United States)

    Alluri, Nagamalleswara Rao; Vivekananthan, Venkateswaran; Chandrasekhar, Arunkumar; Kim, Sang-Jae

    2018-01-18

    Contrary to traditional planar flexible piezoelectric nanogenerators (PNGs), highly adaptable hemispherical shape-flexible piezoelectric composite strip (HS-FPCS) based PNGs are required to harness/measure non-linear surface motions. Therefore, a feasible, cost-effective and less-time consuming groove technique was developed to fabricate adaptable HS-FPCSs with multiple lengths. A single HS-CSPNG generates 130 V/0.8 μA and can also work as a self-powered muscle monitoring system (SP-MMS) to measure maximum human body part movements, i.e., spinal cord, throat, jaw, elbow, knee, foot stress, palm hand/finger force and inhale/exhale breath conditions at a time or at variable time intervals.

  12. Self-powered 'AND' logic circuit of dynamic type with positive safety and application of said 'AND' circuit

    International Nuclear Information System (INIS)

    Lefebvre, Claude; Therond, J.P.

    1974-01-01

    The present invention relates to a self-powered 'AND' logic circuit of dynamic type with positive safety, which delivers on duty operation an output signal equal to the logic product of the input logic signals. The invention relates also to the use of said 'AND' logic circuits in developing n/m logics also of dynamic types with positive safety, delivering on duty operation a zero valued signal when, at least n of the m input signals have the value zero. This type of logics can be inserted in nuclear reactor protection systems; when the value of the reactor operating physical characteristics go out of the safety margins, or true trouble affects 'AND' circuits the value of the output signal is zero, that triggers off the safety absorber drap, for instance [fr

  13. A self-powered biosensing device with an integrated hybrid biofuel cell for intermittent monitoring of analytes.

    Science.gov (United States)

    Majdecka, Dominika; Draminska, Sylwia; Janusek, Dariusz; Krysinski, Paweł; Bilewicz, Renata

    2018-04-15

    In this work, we propose an integrated self-powered sensing system, driven by a hybrid biofuel cell (HBFC) with carbon paper discs coated with multiwalled carbon nanotubes. The sensing system has a biocathode made from laccase or bilirubin oxidase, and the anode is made from a zinc plate. The system includes a dedicated custom-built electronic control unit for the detection of oxygen and catechol analytes, which are central to medical and environmental applications. Both the HBFC and sensors, operate in a mediatorless direct electron transfer mode. The measured characteristics of the HBFC with externally applied resistance included the power-time dependencies under flow cell conditions, the sensors performance (evaluated by cyclic voltammetry), and chronoamperometry. The HBFC is integrated with analytical devices and operating in a pulse mode form long-run monitoring experiments. The HBFC generated sufficient power for wireless data transmission to a local computer. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. High sensitivity, fast speed and self-powered ultraviolet photodetectors based on ZnO micro/nanowire networks

    Directory of Open Access Journals (Sweden)

    Zhiming Bai

    2014-02-01

    Full Text Available Ultraviolet (UV photodetectors (PDs based on ZnO micro/nanowire (MNW networks with Pt contacts have been fabricated on glass substrates. The PDs exhibited a high photosensitivity (5×103 for 365 nm UV light with a fast recovery time (0.2 s at a reverse bias voltage of 2 V. The light induced modulation of Schottky barrier and MNW–MNW junction barrier was employed to account for the results. It was also observed that the PD had a high on–off ratio of 800 without external bias. The photovoltaic effect was proposed to explain the self-powered phenomenon.

  15. A self-powered nano-photodetector based on PFH/ZnO nanorods organic/inorganic heterojunction

    Directory of Open Access Journals (Sweden)

    Xiaoyun Li

    2018-03-01

    Full Text Available PFH/ZnO nanorods heterojunctions were fabricated by spin-coating p-type Poly (9,9-dihexylfluorene (PFH on n-type vertically aligned ZnO nanorod arrays grown by a facile hydrothermal method on indium tin oxide (ITO transparent conductive glass. A typical p-n junction behavior was observed in the fabricated heterojunction. The current of heterojunction increases and decreases dramatically by switching the illumination on and off at zero bias, showing potential self-powered photodetector applications. The heterojunction were capable of generating negative current when illuminated under an appropriate wavelength. The photoresponse properties of the heterojunction can be tuned by the applied bias. In vacuum, the rectifying behavior disappeared, and show only simple semiconductor behavior. Band structure of the heterojunction was schematic drawn and explain the mechanism of the properties of PFH/ZnO nanorods heterojunctions.

  16. Application of the self-powered detector concept in the design of a threshold gamma-ray detector

    International Nuclear Information System (INIS)

    LeVert, F.E.

    1979-01-01

    The self-powered detector concept has been utilized to develop an energy threshold gamma-ray detector. Gamma-ray energy discrimination is achieved by using a thick annular lead shield around the outer wall (emitter) of the detector in conjunction with a self-shielding central electrode (collector). Measurements conducted in the graphite pit of the Argonne Thermal Source Reactor have confirmed its ability to detect high-energy prompt fission gamma rays while discriminating against a significant flux of low-energy gamma rays from the decay of fission products. Also, auto-power spectral densities obtained with the detector were used to estimate the kinetic parameter, β/l, of the reactor

  17. Implementation of a robust hybrid rotary-translational vibration energy harvester for autonomous self-powered acceleration measurement

    Science.gov (United States)

    Payne, Owen R.; Vandewater, Luke A.; Ung, Chandarin; Moss, Scott D.

    2015-04-01

    In this paper, a self-powered wireless sensor node utilising ambient vibrations for power is described. The device consists of a vibration energy harvester, power management system, microcontroller, accelerometer, RF transmitter/receiver and external LED indicators. The vibration energy harvester is adapted from a previously reported hybrid rotary-translational device and uses a pair of copper coil transducers to convert the mechanical energy of a magnetic sphere into usable electricity. The device requires less than 0.8 mW of power to operate continuously in its present setup (with LED indicators off) while measuring acceleration at a sample rate of 200 Hz, with the power source providing 39.7 mW of power from 500 mg excitations at 5.5 Hz. When usable input energy is removed, the device will continue to transmit data for more than 5 minutes.

  18. ZnO nanotube-based dye-sensitized solar cell and its application in self-powered devices

    KAUST Repository

    Han, Jingbin

    2010-09-10

    Abstract High-density vertically aligned ZnO nanotube arrays were fabricated on FTO substrates by a simple and facile chemical etching process from electrodeposited ZnO nanorods. The nanotube formation was rationalized in terms of selective dissolution of the (001) polar face. The morphology of the nanotubes can be readily controlled by electrodeposition parameters for the nanorod precursor. By employing the 5.1 μm-length nanotubes as the photoanode for a dye-sensitized solar cell (DSSC), a full-sun conversion efficiency of 1.18% was achieved. Furthermore, we show that the DSSC unit can serve as a robust power source to drive a humidity sensor, with a potential for self-powered devices. © 2010 IOP Publishing Ltd.

  19. Nanogenerator-based dual-functional and self-powered thin patch loudspeaker or microphone for flexible electronics

    Science.gov (United States)

    Li, Wei; Torres, David; Díaz, Ramón; Wang, Zhengjun; Wu, Changsheng; Wang, Chuan; Lin Wang, Zhong; Sepúlveda, Nelson

    2017-05-01

    Ferroelectret nanogenerators were recently introduced as a promising alternative technology for harvesting kinetic energy. Here we report the device's intrinsic properties that allow for the bidirectional conversion of energy between electrical and mechanical domains; thus extending its potential use in wearable electronics beyond the power generation realm. This electromechanical coupling, combined with their flexibility and thin film-like form, bestows dual-functional transducing capabilities to the device that are used in this work to demonstrate its use as a thin, wearable and self-powered loudspeaker or microphone patch. To determine the device's performance and applicability, sound pressure level is characterized in both space and frequency domains for three different configurations. The confirmed device's high performance is further validated through its integration in three different systems: a music-playing flag, a sound recording film and a flexible microphone for security applications.

  20. Hot Corrosion of Cobalt-Base Alloys

    Science.gov (United States)

    1975-06-01

    Alloys 20. ABSTRACT (Continue on revet -se tside lf necessary and identify by block number) ~ lThe sodium sulfate-induced hot corrosion of cobalt and...Figures 12 and 13. The Na2 SO 4 was observed to form puddles on the oxide-covered specimen surface. An oxide slag was usually suspended in the... slag (black arrows) were suspended (30 sees at 1000°C in air). b) After washing the Na2SO 4 from the specimen, the exposed oxide surface was highly