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Sample records for nanosized rods grown

  1. Nanosized rods agglomerates as a new approach for formulation of a dry powder inhaler

    OpenAIRE

    Salem, HF; Abdelrahim, ME; Eid, K Abo; Sharaf, MA

    2011-01-01

    HF Salem1 ME Abdelrahim2 K Abo Eid3 MA Sharaf3,41Department of Pharmaceutics, 2Department of Clinical Pharmacy, Faculty of Pharmacy, The University of Beni Suef, Beni Suef; 3Department of Chemistry, Helwan University, Ain Helwan, Helwan, Egypt; 4Department of Chemistry, The American University in Cairo, New Cairo, Helwan 11835, EgyptBackground: Nanosized dry powder inhalers provide higher stability for poorly water-soluble drugs as compared with liquid formulations. However, the respirable pa...

  2. Nanosized rods agglomerates as a new approach for formulation of a dry powder inhaler.

    Science.gov (United States)

    Salem, Hf; Abdelrahim, Me; Eid, K Abo; Sharaf, Ma

    2011-01-01

    Nanosized dry powder inhalers provide higher stability for poorly water-soluble drugs as compared with liquid formulations. However, the respirable particles must have a diameter of 1-5 μm in order to deposit in the lungs. Controlled agglomeration of the nanoparticles increases their geometric particle size so they can deposit easily in the lungs. In the lungs, they fall apart to reform nanoparticles, thus enhancing the dissolution rate of the drugs. Theophylline is a bronchodilator with poor solubility in water. Nanosized theophylline colloids were formed using an amphiphilic surfactant and destabilized using dilute sodium chloride solutions to form the agglomerates. The theophylline nanoparticles thus obtained had an average particle size of 290 nm and a zeta potential of -39.5 mV, whereas the agglomerates were 2.47 μm in size with a zeta potential of -28.9 mV. The release profile was found to follow first-order kinetics (r(2) > 0.96). The aerodynamic characteristics of the agglomerated nanoparticles were determined using a cascade impactor. The behavior of the agglomerate was significantly better than unprocessed raw theophylline powder. In addition, the nanoparticles and agglomerates resulted in a significant improvement in the dissolution of theophylline. The results obtained lend support to the hypothesis that controlled agglomeration strategies provide an efficient approach for the delivery of poorly water-soluble drugs into the lungs.

  3. Growth and Characterization of PbO Nano rods Grown using Facile Oxidation of Lead Sheet

    International Nuclear Information System (INIS)

    Yousefi, R.; Sheini, F.J.; Saaedi, A.; Cheraghizade, M.

    2015-01-01

    PbO nano rods were synthesized by oxidation of lead sheets under an oxygen ambience with different temperatures at 330, 400, 450 and 550 degree Celsius in a tube furnace. Scanning electron microscope (SEM) results showed that the nano rods started growing on the sheet that was placed at 330 degree Celsius. On the other hand, by increasing of the temperature to 550 degree Celsius more nano rods appeared on the Pb sheet, which were lied on the lead sheet. X-ray diffraction pattern (XRD) indicated that the nano rods had α-PbO structures. However, a few β-PbO phases also appeared for the nano rods. Raman measurements confirmed the XRD results and indicated two Raman active modes that belonged to α-PbO phase for the nano rods. In addition, the Raman spectrum of the nano rods showed a weak peak of the β-PbO structure. The optical properties of the products were characterized using a room temperature photoluminescence (PL) technique. The PL result indicated a band gap for the PbO nano rods in the visible region. (author)

  4. Piezoelectric effect in InAs/InP quantum rod nanowires grown on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Anufriev, Roman; Chauvin, Nicolas, E-mail: nicolas.chauvin@insa-lyon.fr; Bru-Chevallier, Catherine [Université de Lyon, Institut des Nanotechnologies de Lyon (INL)-UMR5270-CNRS, INSA-Lyon, 7 avenue Jean Capelle, 69621 Villeurbanne (France); Khmissi, Hammadi [Université de Monastir, Laboratoire de Micro-Optoélectronique et Nanostructures (LMON), Faculté des Sciences, Avenue de l' environnement, 5019 Monastir (Tunisia); Naji, Khalid; Gendry, Michel [Université de Lyon, Institut des Nanotechnologies de Lyon (INL)-UMR5270-CNRS, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); Patriarche, Gilles [Laboratoire de Photonique et de Nanostructures (LPN), UPR20-CNRS, route de Nozay, 91460 Marcoussis (France)

    2014-05-05

    We report on the evidence of a strain-induced piezoelectric field in wurtzite InAs/InP quantum rod nanowires. This electric field, caused by the lattice mismatch between InAs and InP, results in the quantum confined Stark effect and, as a consequence, affects the optical properties of the nanowire heterostructure. It is shown that the piezoelectric field can be screened by photogenerated carriers or removed by increasing temperature. Moreover, a dependence of the piezoelectric field on the quantum rod diameter is observed in agreement with simulations of wurtzite InAs/InP quantum rod nanowire heterostructures.

  5. Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Quintas, Ignacio; Oujja, Mohamed; Sanz, Mikel; Benitez-Cañete, Antonio [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Chater, Richard J. [Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Cañamares, Maria Vega [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); Marco, José F. [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Castillejo, Marta, E-mail: marta.castllejo@iqfr.csic.es [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)

    2015-02-15

    Highlights: • Micrometric rods obtained by ns pulsed laser deposition of boron carbide at 1064 and 266 nm. • At 1064 nm microrods display crystalline polyhedral shape with sharp edges and flat sides. • Microrods consist of a mixture of boron, boron oxide, boron carbide and aliphatic hydrocarbons. - Abstract: Micrometric size rods have been fabricated via pulsed laser deposition in vacuum from boron carbide targets using nanosecond pulses of 1064 and 266 nm and room temperature Si (1 0 0) substrates. Morphological, structural and chemical characterization of the microrods was made by applying scanning electron microscopy, focussed ion beam microscopy coupled to secondary ion mass spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Ablation at 1064 nm favours the formation of microrods with high aspect ratio, sharp edges and pyramidal tips, typically 10 μm long with a cross section of around 2 μm × 2 μm. Differently, at 266 nm the microrods are of smaller size and present a more globular aspect. The analyses of the microrods provide information about their crystalline nature and composition, based on a mixture which includes boron, boron oxide and boron carbide, and allows discussion of the wavelength dependent growth mechanisms involved.

  6. Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

    Science.gov (United States)

    Lopez-Quintas, Ignacio; Oujja, Mohamed; Sanz, Mikel; Benitez-Cañete, Antonio; Chater, Richard J.; Cañamares, Maria Vega; Marco, José F.; Castillejo, Marta

    2015-02-01

    Micrometric size rods have been fabricated via pulsed laser deposition in vacuum from boron carbide targets using nanosecond pulses of 1064 and 266 nm and room temperature Si (1 0 0) substrates. Morphological, structural and chemical characterization of the microrods was made by applying scanning electron microscopy, focussed ion beam microscopy coupled to secondary ion mass spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Ablation at 1064 nm favours the formation of microrods with high aspect ratio, sharp edges and pyramidal tips, typically 10 μm long with a cross section of around 2 μm × 2 μm. Differently, at 266 nm the microrods are of smaller size and present a more globular aspect. The analyses of the microrods provide information about their crystalline nature and composition, based on a mixture which includes boron, boron oxide and boron carbide, and allows discussion of the wavelength dependent growth mechanisms involved.

  7. Effects of TiO{sub 2} buffer layer on the photoelectrochemical properties of TiO{sub 2} Nano rods grown by modified chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae-hyun; Ha, Jin-wook; Ryu, Hyukhyun [Inje University, Gimhae (Korea, Republic of); Lee, Won-Jae [Dong-Eui University, Busan (Korea, Republic of)

    2015-08-15

    In this study, we grew TiO{sub 2} nano rods on TiO{sub 2}-film buffered FTO substrate using modified chemical bath deposition (M-CBD). The TiO{sub 2} buffer layer was grown by spin coating method with different RPM (revolutions per minute) values and deposition cycles. We investigated the effects of the RPM values and the deposition cycles on the morphological, structural and photoelectrochemical properties of TiO{sub 2} nano rods. In this work, we have also found that the morphological and structural properties of TiO{sub 2} nano rods affected the photoelectrochemical properties of TiO{sub 2} nano rods. And the maximum photocurrent density of 0.34 mA/cm{sup 2} at 0.6V (vs.SCE) was obtained from the buffer layer deposition process condition of 4,000 RPM and two-times buffer layer depositions.

  8. Distribution of Al and in impurities along homogeneous Ge-Si crystals grown by the Czochralski method using Si feeding rod

    Science.gov (United States)

    Kyazimova, V. K.; Alekperov, A. I.; Zakhrabekova, Z. M.; Azhdarov, G. Kh.

    2014-05-01

    A distribution of Al and In impurities in Ge1 - x Si x crystals (0 ≤ x ≤ 0.3) grown by a modified Czochralski method (with continuous feeding of melt using a Si rod) have been studied experimentally and theoretically. Experimental Al and In concentrations along homogeneous crystals have been determined from Hall measurements. The problem of Al and In impurity distribution in homogeneous Ge-Si single crystals grown in the same way is solved within the Pfann approximation. A set of dependences of Al and In concentrations on the crystal length obtained within this approximation demonstrates a good correspondence between the experimental and theoretical data.

  9. Study of Structural and Optical Properties of Zinc Oxide Rods Grown on Glasses by Chemical Spray Pyrolysis

    OpenAIRE

    Sonmez, Erdal; Aydin, Serdar; Yilmaz, Mehmet; Yurtcan, Mustafa Tolga; Karacali, Tevhit; Ertugrul, Mehmet

    2012-01-01

    We have investigated morphological and optical properties of zinc oxide rods. Highly structured ZnO layers comprising with well-shaped hexagonal rods were prepared by spray pyrolysis deposition of zinc chloride aqueous solutions at ~550∘C. The rods were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, photoluminescence, and ultraviolet and visible absorption spectroscopy measurements. The deposition of the 0.1 mol/L solution at ~550∘C resulted in crys...

  10. Single-crystal SrTiO3 fiber grown by laser heated pedestal growth method: influence of ceramic feed rod preparation in fiber quality

    Directory of Open Access Journals (Sweden)

    D. Reyes Ardila

    1998-10-01

    Full Text Available The rapidly spreading use of optical fiber as a transmission medium has created an interest in fiber-compatible optical devices and methods for growing them, such as the Laser Heated Pedestal Growth (LHPG. This paper reports on the influence of the ceramic feed rod treatment on fiber quality and optimization of ceramic pedestal processing that allows improvements to be made on the final quality in a simple manner. Using the LHPG technique, transparent crack-free colorless single crystal fibers of SrTiO3 (0.50 mm in diameter and 30-40 mm in length were grown directly from green-body feed rods, without using external oxygen atmosphere.

  11. Study of Structural and Optical Properties of Zinc Oxide Rods Grown on Glasses by Chemical Spray Pyrolysis

    Directory of Open Access Journals (Sweden)

    Erdal Sonmez

    2012-01-01

    Full Text Available We have investigated morphological and optical properties of zinc oxide rods. Highly structured ZnO layers comprising with well-shaped hexagonal rods were prepared by spray pyrolysis deposition of zinc chloride aqueous solutions at ~550∘C. The rods were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, photoluminescence, and ultraviolet and visible absorption spectroscopy measurements. The deposition of the 0.1 mol/L solution at ~550∘C resulted in crystals with a diameter of 400–1000 nm and length of 500–2000 nm. Sharp near-band edge emission peaks, centered at 3844 and 3680 Å, dominated the PL spectra of ZnO at 300 K and 6.2 K, respectively. In addition to this, absorption coefficient was determined by absorption measurement. X-ray diffraction, scanning electron microscopy and atomic force microscopy, results suggest that ZnO rods, prepared by spray pyrolysis, have high crystalline quality. This is desirable in nanotechnology applications.

  12. Synthesis and application of highly ordered arrays of TiO2 rods grown on electrospun PVDF fibers

    Science.gov (United States)

    Zhang, Zhi-Guang; Liu, Hui; Zhang, Bin; Zhang, Jun; Liu, Rong-Zhan; Ning, Xin; Long, Yun-Ze

    2017-07-01

    This paper reports the controlled synthesis of highly ordered arrays of rutile TiO2 rods with tunable size and properties on electrospun PVDF Fibers by using a low-temperature hydrothermal growth strategy. Well-defined, highly ordered, vertically oriented TiO2 rod arrays covering on the PVDF fibers backbone were obtained. In order to study the morphology-dependent optical and photocatalytic properties of the hierarchical composites, the hydrothermal treatment time was varied, resulting in rime-like (6 h) and rod bundles (4 h and 10 h) morphologies. By contrast, the crystallinity, grain size and optical properties of the sample depended on the hydrothermal treatment time. After being irradiated for 600 min with an 18 W UV lamp, the photocatalytic efficiency of rhodamine B for the sample hydrothermal treated for 4 h, 6 h and 10 h was about 28%, 37% and 85%, respectively. A slight decrease in the photodegradation efficiency can be detected after five times recycled experiments. Moreover, further study indicates that the rime-like branched structure promote photocatalytic efficiency.

  13. Structural and spectroscopic characterization of Ce0.4Zr0.6O2 crystalline rods grown by the Laser Floating Zone method

    Directory of Open Access Journals (Sweden)

    Várez, A.

    2008-06-01

    Full Text Available A structural and spectroscopic characterization of crystalline rods of Ce0.4Zr0.6O2 grown by the laser floating zone (LFZ method is presented. A precursor rod of Ce0.4Zr0.6O2 composition was sintered at 1500 ºC in air atmosphere and then processed by the LFZ technique with a CO2 laser. The processed material was characterized by XRD, SEM and Raman spectroscopy. In the as-grown, dark-color processed rod, the Raman spectrum evolves radially from a t’-like one, corresponding to Ce0.37Zr0.63O2 composition, at the edge of the rod, to a very broad and weak, cubic-like one, at the center. The degree of cerium reduction and oxygen non-stoichiometry were determined through measurements of the electronic Raman spectrum of Ce3+. A strong Ce3+ signal was found at the core of the rod, indicating strong reduction, whereas no Ce3+ signal was detected at the edge. To restore oxygen and Ce4+ content a section of the fiber was reoxidized at 620 ºC for 24 h. A very homogeneous spectrum was found in the reoxidized sample, that was assigned to a t’-phase of composition Ce0.42Zr0.58O2.Presentamos una caracterización estructural y espectroscópica de fibras cristalinas de Ce0.4Zr0.6O2 crecidas mediante fusión zonal asistida por láser (LFZ. Una barra del material precursor, de composición Ce0.4Zr0.6O2, fue sinterizada a 1500 ºC en atmósfera de aire y después procesada por LFZ con un láser de CO2. El material procesado fue caracterizado por difracción de rayos X, microscopía electrónica de barrido y espectroscopía Raman. En la fibra recién procesada, de color gris oscuro, el espectro Raman varía radialmente desde un espectro de tipo t’, correspondiente a una composición Ce0.37Zr0.63O2, en el borde de la fibra, hasta un espectro muy ensanchado y débil, de aspecto cúbico, en el centro. El grado de reducción del cerio y la no estequiometría del oxígeno se determinaron a través de las medidas del Raman electrónico del Ce3+. La señal de Ce3

  14. ZnO Rods with Exposed {100} Facets Grown via a Self-Catalyzed Vapor-Solid Mechanism and Their Photocatalytic and Gas Sensing Properties

    Czech Academy of Sciences Publication Activity Database

    Vallejos, S.; Pizúrová, Naděžda; Gracia, I.; Sotelo-Vazquez, C.; Cechal, J.; Blackman, C.; Parkin, I.; Cane, C.

    2016-01-01

    Roč. 8, č. 48 (2016), s. 33335-33342 ISSN 1944-8244 Institutional support: RVO:68081723 Keywords : ZnO * rods * AACVD * gas sensing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 7.504, year: 2016

  15. Control rods

    International Nuclear Information System (INIS)

    Maruyama, Hiromi.

    1984-01-01

    Purpose: To realize effective utilization, cost reduction and weight reduction in neutron absorbing materials. Constitution: Residual amount of neutron absorbing material is averaged between the top end region and other regions of a control rod upon reaching to the control rod working life, by using a single kind of neutron absorbing material and increasing the amount of the neutron absorber material at the top end region of the control rod as compared with that in the other regions. Further, in a case of a control rod having control rod blades such as in a cross-like control rod, the amount of the neutron absorbing material is decreased in the middle portion than in the both end portions of the control rod blade along the transversal direction of the rod, so that the residual amount of the neutron absorbing material is balanced between the central region and both end regions upon reaching the working life of the control rod. (Yoshihara, H.)

  16. Rodding Surgery

    Science.gov (United States)

    ... usually undertaken as a scheduled elective procedure. An optimal age for a first rodding surgery has not ... which may prevent or postpone the need for replacement. The smallest diameter expanding rods are still too ...

  17. Control rod

    International Nuclear Information System (INIS)

    Igarashi, Takao; Sugawara, Satoshi; Yoshimoto, Yuichiro; Saito, Shozo; Fukumoto, Takashi.

    1987-01-01

    Purpose: To reduce the weight and thereby obtain satisfactory operationability of control rods by combining absorbing nuclear chain type neutron absorbers and conventional type neutron absorbers in the axial direction of blades. Constitution: Neutron absorber rods and long life type neutron absorber rods are disposed in a tie rod and a sheath. The neutron absorber rod comprises a poison tube made of stainless steels and packed with B 4 C powder. The long life type neutron absorber rod is prepared by packing B-10 enriched boron carbide powder into a hafnium metal rod, hafnium pipe, europium and stainless made poison tube. Since the long life type absorber rod uses HF as the absorbing nuclear chain type neutron absorber, it absorbs neutrons to form new neutron absorbers to increase the nuclear life. (Yoshino, Y.)

  18. Control rod

    International Nuclear Information System (INIS)

    Takahashi, Akio.

    1982-01-01

    Purpose: To prevent distortion in control rod elements such as cladding tubes by decreasing the temperature difference between them. Constitution: In the case of housing a plurality of control rod elements in a protection pipe, flow rate control members are disposed in the protection pipe to equalize the flow resistance in each of coolant flow passages formed between the control rod elements and between the control rod elements and the inner surface of the protection pipe, to thereby unify the flow rate of the coolants flowing through these coolant flowing passages. Accordingly, each of the control rod elements can be cooled uniformly to thereby unify the temperature distribution and avoid the distortion in the cladding tubes, which may be resulted from bending due to the difference in thermal expansion and ununiform swelling due to the temperature difference. (Aizawa, K.)

  19. Fuel rods

    International Nuclear Information System (INIS)

    Hattori, Shinji; Kajiwara, Koichi.

    1980-01-01

    Purpose: To ensure the safety for the fuel rod failures by adapting plenum springs to function when small forces such as during transportation of fuel rods is exerted and not to function the resilient force when a relatively great force is exerted. Constitution: Between an upper end plug and a plenum spring in a fuel rod, is disposed an insertion member to the lower portion of which is mounted a pin. This pin is kept upright and causes the plenum spring to function resiliently to the pellets against the loads due to accelerations and mechanical vibrations exerted during transportation of the fuel rods. While on the other hand, if a compression force of a relatively high level is exerted to the plenum spring during reactor operation, the pin of the insertion member is buckled and the insertion member is inserted to the inside of the plenum spring, whereby the pellets are allowed to expand freely and the failures in the fuel elements can be prevented. (Moriyama, K.)

  20. Control rod

    International Nuclear Information System (INIS)

    Fukumoto, Takashi; Hirakawa, Hiromasa; Kawashima, Norio; Goto, Yasuyuki.

    1994-01-01

    Neutron absorbers are contained in a tubular member comprising, integrally a tubular portion and four corners disposed at the outer circumference of the tubular portion at every 90deg, to provide a neutron absorbing tube. A plurality of neutron absorbing tubes are arranged in parallel in the lateral direction, and adjacent corners are joined, into a blade to constitute a control rod. Such a control rod has a great structural strength, simple in the structure and relatively light in weight and can contain a great amount of neutron absorbers. Upon formation of the control rod by arranging the blades in a cross-like shape, at least a portion thereof is constituted with short neutron absorbing tubes shorter than the entire length of the blade, and gaps are formed at positions in adjacent in the axial direction. With such a constitution, there is no worry that a wing end of the blade collides against or be abraded with a fuel channel box or a fuel support. Even if fuel channels are vibrated upon scram of the reactor, such as occurrence of earthquakes, it can be inserted to the reactor easily. (N.H.)

  1. Fuel rods

    International Nuclear Information System (INIS)

    Fukushima, Kimichika.

    1984-01-01

    Purpose: To reduce the size of the reactor core upper mechanisms and the reactor container, as well as decrease the nuclear power plant construction costs in reactors using liquid metals as the coolants. Constitution: Isotope capturing devices comprising a plurality of pipes are disposed to the gas plenum portion of a nuclear fuel rod main body at the most downstream end in the flowing direction of the coolants. Each of the capturing devices is made of nickel, nickel alloys, stainless steel applied with nickel plating on the surface, nickel alloys applied with nickel plating on the surface or the like. Thus, radioactive nuclides incorporated in the coolants are surely captured by the capturing devices disposed at the most downstream end of the nuclear fuel main body as the coolants flow along the nuclear fuel main body. Accordingly, since discharging of radioactive nuclides to the intermediate fuel exchange system can be prevented, the maintenance or reparing work for the system can be facilitated. (Moriyama, K.)

  2. Rod examination gauge

    Energy Technology Data Exchange (ETDEWEB)

    Bacvinskas, W.S.; Bayer, J.E.; Davis, W.W.; Fodor, G.; Kikta, T.J.; Matchett, R.L.; Nilsen, R.J.; Wilczynski, R.

    1991-12-31

    The present invention is directed to a semi-automatic rod examination gauge for performing a large number of exacting measurements on radioactive fuel rods. The rod examination gauge performs various measurements underwater with remote controlled machinery of high reliability. The rod examination gauge includes instruments and a closed circuit television camera for measuring fuel rod length, free hanging bow measurement, diameter measurement, oxide thickness measurement, cladding defect examination, rod ovality measurement, wear mark depth and volume measurement, as well as visual examination. A control system is provided including a programmable logic controller and a computer for providing a programmed sequence of operations for the rod examination and collection of data.

  3. Control rod drives

    International Nuclear Information System (INIS)

    Nakamura, Akira.

    1984-01-01

    Purpose: To enable to monitor the coupling state between a control rod and a control rod drive. Constitution: After the completion of a control rod withdrawal, a coolant pressure is applied to a control rod drive being adjusted so as to raise only the control rod drive and, in a case where the coupling between the control rod drive and the control rod is detached, the former is elevated till it contacts the control rod and then stopped. The actual stopping position is detected by an actual position detection circuit and compared with a predetermined position stored in a predetermined position detection circuit. If both of the positions are not aligned with each other, it is judged by a judging circuit that the control rod and the control rod drives are not combined. (Sekiya, K.)

  4. FUEL ROD ASSEMBLY

    Science.gov (United States)

    Hutter, E.

    1959-09-01

    A cluster of nuclear fuel rods aod a tubular casing through which a coolant flows in heat-change contact with the ruel rods are described. The casting is of trefoil section and carries the fuel rods, each of which has two fin engaging the serrated fins of the other two fuel rods, whereby the fuel rods are held in the casing and are interlocked against relative longitudinal movement.

  5. Control rod displacement

    International Nuclear Information System (INIS)

    Nakazato, S.

    1987-01-01

    This patent describes a nuclear reactor including a core, cylindrical control rods, a single support means supporting the control rods from their upper ends in spaced apart positions and movable for displacing the control rods in their longitudinal direction between a first end position in which the control rods are fully inserted into the core and a second end position in which the control rods are retracted from the core, and guide means contacting discrete regions of the outer surface of each control rod at least when the control rods are in the vicinity of the second end position. The control rods are supported by the support means for longitudinal movement without rotation into and out of the core relative to the guide means to thereby cause the outer surface of the control rods to experience wear as a result of sliding contact with the guide means. The support means are so arranged with respect to the core and the guide means that it is incapable of rotation relative to the guide means. The improvement comprises displacement means being operatively coupled to a respective one of the control rods for periodically rotating the control rod in a single angular direction through an angle selected to change the locations on the outer surfaces of the control rods at which the control rods are contacted by the guide means during subsequent longitudinal movement of the control rods

  6. Control rod blocking monitor

    International Nuclear Information System (INIS)

    Suzuki, Shigeru.

    1993-01-01

    The number of times for setting up a control rod blocking monitor of a BWR type power plant is remarkably reduced to mitigate operator's burden. In the control rod blocking monitor, trip levels, as a judging standard upon outputting control rod blocking inhibition signals, are set up stepwise depending on the power level around control rods put to blocking control. The present invention comprises an allowance judging means capable of setting up trip levels for each of power levels corresponding to a plurality of control rods at once if the power levels are within the set up allowable range. With such a constitution, the set up allowable range is determined previously in the allowance judging means. Accordingly, when a gang blocking is conducted to control rods, if power levels around the control rods are increased at once into the set up allowable range, the trip levels for each of the control rods are set up at once. (I.S.)

  7. Tie rod insertion test

    CERN Multimedia

    B. LEVESY

    2002-01-01

    The superconducting coil is inserted in the outer vaccum tank and supported by a set of tie rods. These tie rods are made of titanium alloy. This test reproduce the final insertion of the tie rods inside the outer vacuum tank.

  8. Distribution of impurities in monocrystalline Ge rods growth in a rectangular working zone by a group method

    CERN Document Server

    Okun, L S; Zatulovskii, L M; Levinzon, L I; Sachkov, G V; Chaikin, P M

    1973-01-01

    Seven rods were grown together, without rotation of former or crucible. The rods of diameter 8mm were grown at 2mm/min. Specific resistance and Hall effect measurements along the length of the rods revealed that there was a periodicity in these properties, having a 900 mu cycle. Specific resistance varied by 10 189184n a cycle. Single probe resistance measurements revealed a concentration of impurities at the surface of the rods. (3 refs).

  9. Fuel rod leak detector

    International Nuclear Information System (INIS)

    Womack, R.E.

    1978-01-01

    A typical embodiment of the invention detects leaking fuel rods by means of a radiation detector that measures the concentration of xenon-133 ( 133 Xe) within each individual rod. A collimated detector that provides signals related to the energy of incident radiation is aligned with one of the ends of a fuel rod. A statistically significant sample of the gamma radiation (γ-rays) that characterize 133 Xe is accumulated through the detector. The data so accumulated indicates the presence of a concentration of 133 Xe appropriate to a sound fuel rod, or a significantly different concentration that reflects a leaking fuel rod

  10. Compacting spent fuel rods

    International Nuclear Information System (INIS)

    Wachter, W.J.

    1988-01-01

    A method and apparatus for compacting spent fuel rods comprises transferring the rods from a nuclear fuel rod assembly into a different nuclear fuel rod container having a smaller cross section than the assembly. The individual rods are moved from a fuel assembly and through a transition funnel by movable grippers at opposite ends of the funnel. One movable gripper reciprocates between gripping and release positions in a gap between the fuel assembly and the transition funnel. All of the fuel rods are withdrawn concurrently and are merged towards one another into a tighter array within the transition funnel and emerge as a bundle. A movable and a stationary bundle gripper are provided between the funnel and the storage container to advance the bundle of fuel rods into the container. (author)

  11. Control rod drives

    International Nuclear Information System (INIS)

    Shimano, Kunio; Nakamura, Akira; Mizuguchi, Koji; Sakai, Kazuhito; Mitsui, Hisayasu.

    1994-01-01

    The present invention concerns upper-built-in type control rod drives of a BWR type reactor. Namely, high temperature linear motor driving type control rod drives are disposed in an upper space of the reactor pressure vessel, which generates electromagnetic power. In usual driving of control rods, driving shafts connected with control rods by a high temperature linear motor driving system comprising a driving shaft having an iron core inserted therein and electromagnetic coils is vertically moved to insert/withdraw the control rods to and from the reactor core. Upon occurrence of reactor scram, electric power source is interrupted, and the control rods are rapidly inserted to the reactor core. According to the present invention, since the control rod drives are disposed in the space above the reactor pressure vessel, pipelines or equipments passing through the bottom of the reactor pressure vessel can be saved. As a result, operation for maintenance and inspection is facilitated. (I.S.)

  12. CONTROL ROD DRIVE

    Science.gov (United States)

    Chapellier, R.A.

    1960-05-24

    BS>A drive mechanism was invented for the control rod of a nuclear reactor. Power is provided by an electric motor and an outside source of fluid pressure is utilized in conjunction with the fluid pressure within the reactor to balance the loadings on the motor. The force exerted on the drive mechanism in the direction of scramming the rod is derived from the reactor fluid pressure so that failure of the outside pressure source will cause prompt scramming of the rod.

  13. Dynamic Rod Worth Measurement

    International Nuclear Information System (INIS)

    Chao, Y.A.; Chapman, D.M.; Hill, D.J.; Grobmyer, L.R.

    2000-01-01

    The dynamic rod worth measurement (DRWM) technique is a method of quickly validating the predicted bank worth of control rods and shutdown rods. The DRWM analytic method is based on three-dimensional, space-time kinetic simulations of the rapid rod movements. Its measurement data is processed with an advanced digital reactivity computer. DRWM has been used as the method of bank worth validation at numerous plant startups with excellent results. The process and methodology of DRWM are described, and the measurement results of using DRWM are presented

  14. Why Rods and Cocci

    Indian Academy of Sciences (India)

    experience greater frictional resistance. This hypothesis is supported by the fact that among the flagellated motile bacteria almost all are rod shaped. Only exceptionally few cocci are motile. This hypothesis, however, is not adequate since a large number of species of bacteria are non-motile. A rod shape can confer another ...

  15. Why Rods and Cocci

    Indian Academy of Sciences (India)

    Bacteria exhibit a wide variety of shapes but the commonly studied species of bacteria are generally either spherical in shape which are called cocci (singular coccus) or have a cylindrical shape and are called rods or bacilli (singular bacillus). In reality rods and cocci are the ends of a continuum. Sonle of the cocci are.

  16. Control rod drives

    International Nuclear Information System (INIS)

    Oonuki, Koji.

    1981-01-01

    Purpose: To increase the driving speed of control rods at rapid insertion with an elongate control rod and an extension pipe while ensuring sufficient buffering performance in a short buffering distance, by providing a plurality of buffers to an extension pipe between a control rod drive source and a control rod in LMFBR type reactor. Constitution: First, second and third buffers are respectively provided to an acceleration piston, an extension pipe and a control rod respectively and the insertion positions for each of the buffers are displaced orderly from above to below. Upon disconnection of energizing current for an electromagnet, the acceleration piston, the extension pipe and the control rod are rapidly inserted in one body. The first, second and third buffers are respectively actuated at each of their falling strokes upon rapid insertion respectively, and the acceleration piston, the extension pipe and the control rod receive the deceleration effect in the order correspondingly. Although the compression force is applied to the control rod only near the stroke end, it does not cause deformation. (Kawakami, Y.)

  17. Control rod shutdown system

    International Nuclear Information System (INIS)

    Miyamoto, Yoshiyuki; Higashigawa, Yuichi.

    1996-01-01

    The present invention provides a control rod terminating system in a BWR type nuclear power plant, which stops an induction electric motor as rapidly as possible to terminate the control rods. Namely, the control rod stopping system controls reactor power by inserting/withdrawing control rods into a reactor by driving them by the induction electric motor. The system is provided with a control device for controlling the control rods and a control device for controlling the braking device. The control device outputs a braking operation signal for actuating the braking device during operation of the control rods to stop the operation of the control rods. Further, the braking device has at least two kinds of breaks, namely, a first and a second brakes. The two kinds of brakes are actuated by receiving the brake operation signals at different timings. The brake device is used also for keeping the control rods after the stopping. Even if a stopping torque of each of the breaks is small, different two kinds of brakes are operated at different timings thereby capable of obtaining a large stopping torque as a total. (I.S.)

  18. Control rod driveline and grapple

    International Nuclear Information System (INIS)

    Germer, J.H.

    1987-01-01

    A control rod driveline and grapple for engaging and releasing a control rod from a control rod drive is described comprising an enlarged control rod handle including an upwardly flaring frustum and a rod extending from the control rod handle; a relatively moving outer member; a tension rod connected to the relatively moving outer member at the upper end and provided with a lower annular flange at the lower end, the tension rod including a female cavity for receiving the upwardly extending rod from the enlarged control rod handle; a discrete and independent grapple segments for surrounding and grappling the control rod handle, each grapple segment including a first indentation for engaging and gripping the flange of the tension rod at an upper and interior annulus

  19. Rod Photoreceptors Detect Rapid Flicker

    Science.gov (United States)

    Conner, J. D.; MacLeod, Donald I. A.

    1977-01-01

    Rod-isolation techniques show that light-adapted human rods detect flicker frequencies as high as 28 hertz, and that the function relating rod critical flicker frequency to stimulus intensity contains two distinct branches. (MLH)

  20. Control rod drives

    International Nuclear Information System (INIS)

    Hayakawa, Hiroyasu.

    1979-01-01

    Purpose: To enable rapid control in a simple circuit by providing a motor control device having an electric capacity capable of simultaneously driving all of the control rods rapidly only in the inserting direction as well as a motor controlling device capable of fine control for the insertion and extraction at usual operation. Constitution: The control rod drives comprise a first motor control device capable of finely controlling the control rods both in inserting and extracting directions, a second motor control device capable of rapidly driving the control rods only in the inserting direction, and a first motor switching circuit and a second motor switching circuit switched by switches. Upon issue of a rapid insertion instruction for the control rods, the second motor switching circuit is closed by the switch and the second motor control circuit and driving motors are connected. Thus, each of the control rod driving motors is driven at a high speed in the inserting direction to rapidly insert all of the control rods. (Yoshino, Y.)

  1. Control rod testing apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Gaunt, R.R.; Ashman, C.M.

    1987-06-02

    A control rod testing apparatus is described comprising: a first guide means having a vertical cylindrical opening for grossly guiding a control rod; a second guide means having a vertical cylindrical opening for grossly guiding a control rod. The first and second guide means are supported at axially spaced locations with the openings coaxial; and a substantially cylindrical subassembly having a vertical cylindrical opening therethrough. The subassembly is trapped coaxial with and between the first and second guide means, and the subassembly radially floats with respect to the first and second guide means.

  2. Control rod testing apparatus

    International Nuclear Information System (INIS)

    Gaunt, R.R.; Ashman, C.M.

    1987-01-01

    A control rod testing apparatus is described comprising: a first guide means having a vertical cylindrical opening for grossly guiding a control rod; a second guide means having a vertical cylindrical opening for grossly guiding a control rod. The first and second guide means are supported at axially spaced locations with the openings coaxial; and a substantially cylindrical subassembly having a vertical cylindrical opening therethrough. The subassembly is trapped coaxial with and between the first and second guide means, and the subassembly radially floats with respect to the first and second guide means

  3. Control rod velocity limiter

    International Nuclear Information System (INIS)

    Cearley, J.E.; Carruth, J.C.; Dixon, R.C.; Spencer, S.S.; Zuloaga, J.A. Jr.

    1986-01-01

    This patent describes a velocity control arrangement for a reciprocable, vertically oriented control rod for use in a nuclear reactor in a fluid medium, the control rod including a drive hub secured to and extending from one end therefrom. The control device comprises: a toroidally shaped control member spaced from and coaxially positioned around the hub and secured thereto by a plurality of spaced radial webs thereby providing an annular passage for fluid intermediate the hub and the toroidal member spaced therefrom in coaxial position. The side of the control member toward the control rod has a smooth generally conical surface. The side of the control member away from the control rod is formed with a concave surface constituting a single annular groove. The device also comprises inner and outer annular vanes radially spaced from one another and spaced from the side of the control member away from the control rod and positioned coaxially around and spaced from the hub and secured thereto by spaced radial webs thereby providing an annular passage for fluid intermediate the hub and the vanes. The vanes are angled toward the control member, the outer edge of the inner vane being closer to the control member and the inner edge of the outer vane being closer to the control member. When the control rod moves in the fluid in the direction toward the drive hub the vanes direct a flow of fluid turbulence which provides greater resistance to movement of the control rod in the direction toward the drive hub than in the other direction

  4. Synthesis, characterization and properties of nano-sized transition metal oxides

    Science.gov (United States)

    Yin, Ming

    2005-12-01

    temperature. Chapter 4. Nanosized Copper (I) oxide particles have been prepared by a thereto decomposition of Cu (I) acetate in the presence of oleic acid at high temperature. Nanoparticles from 3.6 net to 10.7 nm could be synthesized by increasing the stoichiometric ratio of surfactant to copper precursor. Chapter 5. Nano-sized ZnO rods are prepared from a simple acetate precursor. The resulting ZnO nanorods are highly crystalline, uniform and with a narrow size distribution, which facilitates the understanding of the optical properties of nanosized ZnO. (Abstract shortened by UMI.)

  5. Control rod assemblies

    International Nuclear Information System (INIS)

    Yamanaka, Toshikatsu.

    1986-01-01

    Purpose: To obtain simple and practical control rod assemblies by bringing the exit temperature of the guide tube of a control rod main body closer to that of an adjacent fuel assembly and thereby suppressing the wasteful flow of coolants. Constitution: A flow control member comprises an annular flow control plate disposed above the control rod main body and bellows having a plurality of small paertures capable of passing coolants therethrough formed at the circumferencial surface. The bellows are to cause the flow control plate to resiliently abut on the upper surface of the control rod main body. Coolants flowing from below to above in the guide tube remove heat from the neutron absorbers and are discharged externally at an elevated temperature, while coolants at a lower temperature are entered and mixed through the apertures formed in the bellows. By the way, upon insertion of the control rod main body, flow of the coolants to the inside of the bellows is substantially interrupted by the extension contraction of the bellows, by which the flow rate is adjusted depending on the withdrawing stroke to suppress the occurrence of thermal problems. (Kamimura, M.)

  6. Control rod housing alignment

    International Nuclear Information System (INIS)

    Dixon, R.C.; Deaver, G.A.; Punches, J.R.; Singleton, G.E.; Erbes, J.G.; Offer, H.P.

    1990-01-01

    This patent describes a process for measuring the vertical alignment between a hole in a core plate and the top of a corresponding control rod drive housing within a boiling water reactor. It comprises: providing an alignment apparatus. The alignment apparatus including a lower end for fitting to the top of the control rod drive housing; an upper end for fitting to the aperture in the core plate, and a leveling means attached to the alignment apparatus to read out the difference in angularity with respect to gravity, and alignment pin registering means for registering to the alignment pin on the core plate; lowering the alignment device on a depending support through a lattice position in the top guide through the hole in the core plate down into registered contact with the top of the control rod drive housing; registering the upper end to the sides of the hole in the core plate; registering the alignment pin registering means to an alignment pin on the core plate to impart to the alignment device the required angularity; and reading out the angle of the control rod drive housing with respect to the hole in the core plate through the leveling devices whereby the angularity of the top of the control rod drive housing with respect to the hole in the core plate can be determined

  7. Hydraulically centered control rod

    International Nuclear Information System (INIS)

    Horlacher, W.R.; Sampson, W.T.; Schukei, G.E.

    1981-01-01

    A control rod suspended to reciprocate in a guide tube of a nuclear fuel assembly has a hydraulic bearing formed at its lower tip. The bearing includes a plurality of discrete pockets on its outer surface into which a flow of liquid is continuously provided. In one embodiment the flow is induced by the pressure head in a downward facing chamber at the end of the bearing. In another embodiment the flow originates outside the guide tube. In both embodiments the flow into the pockets produces pressure differences across the bearing which counteract forces tending to drive the rod against the guide tube wall. Thus contact of the rod against the guide tube is avoided

  8. Control rod control device

    International Nuclear Information System (INIS)

    Seiji, Takehiko; Obara, Kohei; Yanagihashi, Kazumi

    1998-01-01

    The present invention provides a device suitable for switching of electric motors for driving each of control rods in a nuclear reactor. Namely, in a control rod controlling device, a plurality of previously allotted electric motors connected in parallel as groups, and electric motors of any selected group are driven. In this case, a voltage of not driving predetermined selected electric motors is at first applied. In this state an electric current supplied to the circuit of predetermined electric motors is detected. Whether integration or failure of a power source and the circuit of the predetermined electric motors are normal or not is judged by the detected electric current supplied. After they are judged normal, the electric motors are driven by a regular voltage. With such procedures, whether the selected circuit is normal or not can be accurately confirmed previously. Since the electric motors are not driven just at the selected time, the control rods are not operated erroneously. (I.S.)

  9. Flow in rod bundles

    International Nuclear Information System (INIS)

    Hazi, G.; Mayer, G.

    2005-01-01

    For power upgrading VVER-440 reactors we need to know exactly how the temperature measured by the thermocouples is related to the average outlet temperature of the fuel assemblies. Accordingly, detailed knowledge on mixing process in the rod bundles and in the fuel assembly head have great importance. Here we study the hydrodynamics of rod bundles based on the results of direct numerical and large eddy simulation of flows in subchannels. It is shown that secondary flow and flow pulsation phenomena can be observed using both methodologies. Some consequences of these observations are briefly discussed. (author)

  10. Device for coupling a control rod and control rod drive

    International Nuclear Information System (INIS)

    Nishioka, Kazuya.

    1975-01-01

    Object: To obtain simple and reliable coupling between a control rod and control rod drive by equipping the lower end of the control rod with an extension provided with lateral protuberances and forming the upper end of an index tube with a recess provided with lateral holes. Structure: The tapering central extension of the control rod is inserted into the recess by lowering the control rod, and then it is further inserted by causing frictional movement of the inclined surfaces of lateral protuberances in frictional contact with guide surfaces. When the lateral protuberances are brought into contact with a stepped portion, the control rod is rotated to fit the lateral protuberances into the lateral holes. In this way, the control rod is coupled to the index tube of the control rod drive. (Yoshino, Y.)

  11. Control rod driving mechanisms

    International Nuclear Information System (INIS)

    Maejima, Yoshinori.

    1986-01-01

    Purpose: To conduct reactor scram by an external signal and, also by a signal for the abnormal temperature from a temperature detector in the nuclear reactor. Constitution: Control rod driving mechanisms magnetically coupling the extension pipe with the elevating mechanism above the reactor core and the holding magnet, and retains a control rod to the lower portion of the extension pipe by way of a latch mechanism. The temperature detector is immersed in reactor coolants. If the temperature of the coolants rises abnormally, bimetal contacts of the temperature detector are opened to interrupt the current supply to the holding electromagnet. Then, the extension pipe released from the magnetic coupling is lowered and the control rod free from latch is rapidly dropped and inserted into the reactor core. Since this procedure is carried out for all of the control rods, the reactor scram can be attained. The feature of this invention resides in that the reactor scram can be attained also by the signal of the reactor core itself even if the signal system for the external signals should be failed. (Horiuchi, T.)

  12. Evaluation of Extrusion Technique for Nanosizing Liposomes

    Directory of Open Access Journals (Sweden)

    Sandy Gim Ming Ong

    2016-12-01

    Full Text Available The aim of the present study was to study the efficiency of different techniques used for nanosizing liposomes. Further, the aim was also to evaluate the effect of process parameters of extrusion techniques used for nanosizing liposomes on the size and size distribution of the resultant liposomes. To compare the efficiency of different nanosizing techniques, the following techniques were used to nanosize the liposomes: extrusion, ultrasonication, freeze-thaw sonication (FTS, sonication and homogenization. The extrusion technique was found to be the most efficient, followed by FTS, ultrasonication, sonication and homogenization. The extruder used in the present study was fabricated using readily available and relatively inexpensive apparatus. Process parameters were varied in extrusion technique to study their effect on the size and size distribution of extruded liposomes. The results obtained indicated that increase in the flow rate of the extrusion process decreased the size of extruded liposomes however the size homogeneity was negatively impacted. Furthermore, the liposome size and distribution was found to decline with decreasing membrane pore size. It was found that by extruding through a filter with a pore size of 0.2 µm and above, the liposomes produced were smaller than the pore size, whereas, when they were extruded through a filter with a pore size of less than 0.2 µm the resultant liposomes were slightly bigger than the nominal pore size. Besides that, increment of extrusion temperature above transition temperature of the pro-liposome had no effect on the size and size distribution of the extruded liposomes. In conclusion, the extrusion technique was reproducible and effective among all the methods evaluated. Furthermore, processing parameters used in extrusion technique would affect the size and size distribution of liposomes. Therefore, the process parameters need to be optimized to obtain a desirable size range and homogeneity

  13. Nanosizing techniques for improving bioavailability of drugs.

    Science.gov (United States)

    Al-Kassas, Raida; Bansal, Mahima; Shaw, John

    2017-08-28

    The poor solubility of significant number of Active Pharmaceutical Ingredients (APIs) has become a major challenge in the drug development process. Drugs with poor solubility are difficult to formulate by conventional methods and often show poor bioavailability. In the last decade, attention has been focused on developing nanocrystals for poorly water soluble drugs using nanosizing techniques. Nanosizing is a pharmaceutical process that changes the size of a drug to the sub-micron range in an attempt to increase its surface area and consequently its dissolution rate and bioavailability. The effectiveness of nanocrystal drugs is evidenced by the fact that six FDA approved nanocrystal drugs are already on the market. The bioavailabilities of these preparations have been significantly improved compared to their conventional dosage forms. There are two main approaches for preparation of drug nanocrystals; these are the top-down and bottom-up techniques. Top-down techniques have been successfully used in both lab scale and commercial scale manufacture. Bottom-up approaches have not yet been used at a commercial level, however, these techniques have been found to produce narrow sized distribution nanocrystals using simple methods. Bottom-up techniques have been also used in combination with top-down processes to produce drug nanoparticles. The main aim of this review article is to discuss the various methods for nanosizing drugs to improve their bioavailabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Morphoelastic rods. Part I: A single growing elastic rod

    KAUST Repository

    Moulton, D.E.

    2013-02-01

    A theory for the dynamics and statics of growing elastic rods is presented. First, a single growing rod is considered and the formalism of three-dimensional multiplicative decomposition of morphoelasticity is used to describe the bulk growth of Kirchhoff elastic rods. Possible constitutive laws for growth are discussed and analysed. Second, a rod constrained or glued to a rigid substrate is considered, with the mismatch between the attachment site and the growing rod inducing stress. This stress can eventually lead to instability, bifurcation, and buckling. © 2012 Elsevier Ltd. All rights reserved.

  15. REACTOR CONTROL ROD OPERATING SYSTEM

    Science.gov (United States)

    Miller, G.

    1961-12-12

    A nuclear reactor control rod mechanism is designed which mechanically moves the control rods into and out of the core under normal conditions but rapidly forces the control rods into the core by catapultic action in the event of an emergency. (AEC)

  16. Synthesis and testing of nanosized zeolite Y

    Science.gov (United States)

    Karami, Davood

    This work focuses on the synthesis and testing of nanosized zeolite Y. The synthesis formulations of faujasite-type structure of zeolite Y prepared in nanosized form are described. The synthetic zeolite Y is the most widely employed for the preparation of fluid catalytic cracking (FCC) catalysts. The synthesis of zeolite Y is very complicated process. The mean particle size of zeolite Y is 1800 nm. The major challenge of this work involved reducing this average particle size to less than 500 nm. The preliminary experiments were conducted to obtain the pure zeolite Y using the soluble silicates as a silica source. This was achieved by applying the experimental design approach to study the effects of many parameters. The ageing time turned out to be the most significant variable affecting product purity. Based on the preliminary results, a detailed investigation was carried out to determine the effects of silica-alumina precursor preparations on zeolite Y synthesis. Aluminosilicate precursors were prepared by gelling and precipitation of soluble silicate. The as-prepared precursors were used for the hydrothermal synthesis of zeolite Y. The procedure of the precipitation of soluble silicate yielded pure zeolite Y at the conventional synthesis conditions. The extent of purity of zeolite Y depends on the surface areas of aluminosilicate precursors. A novel approach to zeolite Y synthesis was employed for the preparation of the pure nanosized zeolite Y. This was achieved by applying the method of impregnation of precipitated silica. This novel method of impregnation for zeolite Y preparation allows eliminating the vigorous agitation step required for the preparation of a homogeneous silica solution, thereby simplifying the synthesis of zeolite Y in one single vessel. In case of the synthesis of nanosized zeolite Y, the effect of varying the organic templates on the formation of nanosized particles of zeolite Y was investigated, while all other reaction parameters were

  17. Fuel rod attachment system

    International Nuclear Information System (INIS)

    Christiansen, D.W.

    1982-01-01

    A reusable system for removably attaching a nuclear reactor fuel rod to a support member. A locking cap is secured to the fuel rod and a locking strip is fastened to the support member or vice versa. The locking cap has two opposing fingers and shaped to form a socket having a body portion. The locking strip has an extension shaped to rigidly attach to the socket's body portion. The locking cap's fingers are resiliently deflectable. For attachment, the locking cap is longitudinally pushed onto the locking strip causing the extension to temporarily deflect open the fingers to engage the socket's body portion. For removal, the process is reversed. In an alternative embodiment, the cap is rigid and the strip is transversely resiliently compressible. (author)

  18. Fuel rod fixing system

    International Nuclear Information System (INIS)

    Christiansen, D.W.

    1982-01-01

    This is a reusable system for fixing a nuclear reactor fuel rod to a support. An interlock cap is fixed to the fuel rod and an interlock strip is fixed to the support. The interlock cap has two opposed fingers, which are shaped so that a base is formed with a body part. The interlock strip has an extension, which is shaped so that this is rigidly fixed to the body part of the base. The fingers of the interlock cap are elastic in bending. To fix it, the interlock cap is pushed longitudinally on to the interlock strip, which causes the extension to bend the fingers open in order to engage with the body part of the base. To remove it, the procedure is reversed. (orig.) [de

  19. Control rod withdrawal monitoring device

    International Nuclear Information System (INIS)

    Ebisuya, Mitsuo.

    1984-01-01

    Purpose: To prevent the power ramp even if a plurality of control rods are subjected to withdrawal operation at a time, by reducing the reactivity applied to the reactor. Constitution: The control rod withdrawal monitoring device is adapted to monitor and control the withdrawal of the control rods depending on the reactor power and the monitoring region thereof is divided into a control rod group monitoring region a transition region and a control group monitoring not interfere region. In a case if the distance between a plurality of control rods for which the withdrawal positions are selected is less than a limiting value, the coordinate for the control rods, distance between the control rods and that the control rod distance is shorter are displayed on a display panel, and the withdrawal for the control rods are blocked. Accordingly, even if a plurality of control rods are subjected successively to the withdrawal operation contrary to the control rod withdrawal sequence upon high power operation of the reactor, the power ramp can be prevented. (Kawakami, Y.)

  20. Control rod drives

    International Nuclear Information System (INIS)

    Kimura, Koichi.

    1994-01-01

    In control rod drives, differential pressure sensors are disposed at the inlet and the exit of a driving water pressure control valve disposed in a driving water supply device and, when deviation of fluctuation of the differential pressure from a set value is detected, a pressure control valve for driving water is controlled so as to make the differential pressure constant. The differential pressure sensors detect the differential pressure between the pressure of the control rod drives at the inlet and the exit of the driving water pressure control valve and a pressure in a reactor dome. A judging circuit judges whether the differential pressure between both sides of the driving water pressure control valve is deviated from a set value or not and, if it deviates from the set value, outputs of judging signal to the control device. In the control device, the opening degree of the driving water pressure control valve is controlled, so that the differential pressure between both sides of the driving water pressure control value is constant and does not deviate from the set value. There are provided advantageous effects of preventing abnormal control rod withdrawing phenomenon to improve safety and reliability for the control of the reactor operation. (N.H.)

  1. Rod drive and latching mechanism

    International Nuclear Information System (INIS)

    Veronesi, L.; Sherwood, D.G.

    1982-01-01

    Hydraulic drive and latching mechanisms for driving reactivity control mechanisms in nuclear reactors are described. Preferably, the pressurized reactor coolant is utilized to raise the drive rod into contact with and to pivot the latching mechanism so as to allow the drive rod to pass the latching mechanism. The pressure in the housing may then be equalized which allows the drive rod to move downwardly into contact with the latching mechanism but to hold the shaft in a raised position with respect to the reactor core. Once again, the reactor coolant pressure may be utilized to raise the drive rod and thus pivot the latching mechanism so that the drive rod passes above the latching mechanism. Again, the mechanism pressure can be equalized which allows the drive rod to fall and pass by the latching mechanism so that the drive rod approaches the reactor core. (author)

  2. Nanosized Hydroxyapatite Precipitation on the Ti—30Ta—xHf Alloys.

    Science.gov (United States)

    Lee, Kang; Jang, Jae- In; Han-Cheol, Choe

    2017-04-01

    In this study, we prepared hydroxyapatite (HAp) layer on the alkali treated Ti–30Ta–xHf alloys using electrochemical deposition method. Ti–30Ta–xHf alloys was anodized in 5 M NaOH solution at 0.3 A for 10 min. Alkali treated Ti–30Ta–xHf surface formed by anodization step which acted as templates and anchorage for growth of the HAp during subsequent pulsed electrochemical deposition process at 85 °C. The phase and morphologies of deposited HAp layer were affected by the Hf contents of Ti–30Ta–xHf alloys. The nano-scale rod-like HAp layer was formed on untreated Ti–30Ta–xHf alloys with partially low crystallinity. In the case of alkali treated Ti–30Ta–xHf, nano-sized needle-like layers were transferred to nano-flake surface and denser morphology as Hf content increased.

  3. Nanosized lithium titanates produced by plasma technique

    International Nuclear Information System (INIS)

    Grabis, J; Orlovs, A; Rasmane, Dz

    2007-01-01

    The synthesis of nanosized lithium titanates is studied by evaporation of coarse grained commercially available titanium and lithium carbonate particles in radio-frequency plasma flow with subsequent controlling formation and growth conditions of product particles. In accordance with the XRD analysis the phase composition of the obtained powders is determined by feeding rate of precursors and strongly by ratio of lithium and titanium. The Li 2 TiO 3 and Li 4 Ti 5 O 12 particles containing small amounts of extra phases were obtained at ratio of Li/Ti = 2 and Li/Ti = 0.8 respectively, feeding rate of precursors being in the range of 0.6-0.9 kg/h. Specific surface area of powders is in the range of 20-40 m2/g depending on concentration of vapours in gas flow and cooling rate of the products. Additional calcination of nanosize particles at 800-900 deg. C improves phase composition of lithium titanates

  4. Cone rod dystrophies

    Directory of Open Access Journals (Sweden)

    Hamel Christian P

    2007-02-01

    Full Text Available Abstract Cone rod dystrophies (CRDs (prevalence 1/40,000 are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP, also called the rod cone dystrophies (RCDs resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7. Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far. The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs, CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs, and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs. It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is

  5. Effects of nanosized constriction on thermal transport properties of graphene

    Science.gov (United States)

    2014-01-01

    Thermal transport properties of graphene with nanosized constrictions are investigated using nonequilibrium molecular dynamics simulations. The results show that the nanosized constrictions have a significant influence on the thermal transport properties of graphene. The thermal resistance of the nanosized constrictions is on the order of 107 to 109 K/W at 150 K, which reduces the thermal conductivity by 7.7% to 90.4%. It is also found that the constriction resistance is inversely proportional to the width of the constriction and independent of the heat current. Moreover, we developed an analytical model for the ballistic thermal resistance of the nanosized constrictions in two-dimensional nanosystems. The theoretical prediction agrees well with the simulation results in this paper, which suggests that the thermal transport across the nanosized constrictions in two-dimensional nanosystems is ballistic in nature. PACS 65.80.CK; 61.48.Gh; 63.20.kp; 31.15.xv PMID:25232292

  6. Fuel rod pellet loading head

    International Nuclear Information System (INIS)

    Howell, T.E.

    1975-01-01

    An assembly for loading nuclear fuel pellets into a fuel rod comprising a loading head for feeding pellets into the open end of the rod is described. The pellets rest in a perforated substantially V-shaped seat through which air may be drawn for removal of chips and dust. The rod is held in place in an adjustable notched locator which permits alignment with the pellets

  7. Integrated control rod monitoring device

    International Nuclear Information System (INIS)

    Saito, Katsuhiro

    1997-01-01

    The present invention provides a device in which an entire control rod driving time measuring device and a control rod position support device in a reactor building and a central control chamber are integrated systematically to save hardwares such as a signal input/output device and signal cables between boards. Namely, (1) functions of the entire control rod driving time measuring device for monitoring control rods which control the reactor power and a control rod position indication device are integrated into one identical system. Then, the entire devices can be made compact by the integration of the functions. (2) The functions of the entire control rod driving time measuring device and the control rod position indication device are integrated in a central operation board and a board in the site. Then, the place for the installation of them can be used in common in any of the cases. (3) The functions of the entire control rod driving time measuring device and the control rod position indication device are integrated to one identical system to save hardware to be used. Then, signal input/output devices and drift branching panel boards in the site and the central operation board can be saved, and cables for connecting both of the boards is no more necessary. (I.S.)

  8. Nuclear reactor with control rods

    International Nuclear Information System (INIS)

    Obermeyer, F.D.; Berringer, R.T.

    1979-01-01

    A liquid-cooled nuclear reactor including fuel assemblies mounted within a reactor vessel having linearly movable control rods passing through control rod guide tubes into respective aligned fuel assemblies is described. Reactor coolant circulates through the assemblies. Guide tubes and other vessel internals structures located above the assemblies and is discharged through an outlet nozzle positioned above the elevation of primary flow openings in the guide tube walls. The guide tube includes internal horizontal supports and a length limited continuous control rod guide which, in conjunction with the flow openings, alleviate detrimental coolant cross flows and frictional restraints imposed upon the control rods

  9. Nuclear fuel rods

    International Nuclear Information System (INIS)

    Wada, Toyoji.

    1979-01-01

    Purpose: To remove failures caused from combination of fuel-cladding interactions, hydrogen absorptions, stress corrosions or the likes by setting the quantity ratio of uranium or uranium and plutonium relative to oxygen to a specific range in fuel pellets and forming a specific size of a through hole at the center of the pellets. Constitution: In a fuel rods of a structure wherein fuel pellets prepared by compacting and sintering uranium dioxide, or oxide mixture consisting of oxides of plutonium and uranium are sealed with a zirconium metal can, the ratio of uranium or uranium and plutonium to oxygen is specified as 1 : 2.01 - 1 : 2.05 in the can and a passing hole of a size in the range of 15 - 30% of the outer diameter of the fuel pellet is formed at the center of the pellet. This increases the oxygen partial pressure in the fuel rod, oxidizes and forms a protection layer on the inner surface of the can to control the hydrogen absorption and stress corrosion. Locallized stress due to fuel cladding interaction (PCMI) can also be moderated. (Horiuchi, T.)

  10. Rod Microglia: A Morphological Definition

    Science.gov (United States)

    Taylor, Samuel E.; Morganti-Kossmann, Cristina

    2014-01-01

    Brain microglial morphology relates to function, with ramified microglia surveying the micro-environment and amoeboid microglia engulfing debris. One subgroup of microglia, rod microglia, have been observed in a number of pathological conditions, however neither a function nor specific morphology has been defined. Historically, rod microglia have been described intermittently as cells with a sausage-shaped soma and long, thin processes, which align adjacent to neurons. More recently, our group has described rod microglia aligning end-to-end with one another to form trains adjacent to neuronal processes. Confusion in the literature regarding rod microglia arises from some reports referring to the sausage-shaped cell body, while ignoring the spatial distribution of processes. Here, we systematically define the morphological characteristics of rod microglia that form after diffuse brain injury in the rat, which differ morphologically from the spurious rod microglia found in uninjured sham. Rod microglia in the diffuse-injured rat brain show a ratio of 1.79±0.03 cell length∶cell width at day 1 post-injury, which increases to 3.35±0.05 at day 7, compared to sham (1.17±0.02). The soma length∶width differs only at day 7 post-injury (2.92±0.07 length∶width), compared to sham (2.49±0.05). Further analysis indicated that rod microglia may not elongate in cell length but rather narrow in cell width, and retract planar (side) processes. These morphological characteristics serve as a tool for distinguishing rod microglia from other morphologies. The function of rod microglia remains enigmatic; based on morphology we propose origins and functions for rod microglia after acute neurological insult, which may provide biomarkers or therapeutic targets. PMID:24830807

  11. Digital control rod blocking monitor

    International Nuclear Information System (INIS)

    Funayama, Yoshio.

    1996-01-01

    The present invention system is used for monitoring of a power region of a reactor, and used for monitoring of simultaneous withdrawal of a plurality of control rods without increasing the size or complicating the system. Namely, the system processes signals from a neutron flux detectors at the periphery of control rods controlled for withdrawal. As a result of the processing, the digital monitoring system generates an alarm when the reactor power at the periphery of the control rods fluctuates exceeding an allowable range. In the system, a control rod information forming means prepares frame data comprising front data, positions of the control rods to be withdrawn, frame numbers and completion data. A serial data transmitting means transmits the frame data successively as repeating frame data rows. A control rod information receiving means takes up the frame data of each of control rods to be withdrawn from the transmitted frame data rows. Since the system of the present invention can monitor the withdrawal of a plurality of control rods simultaneously without increasing the size or complicating the system, cost can be saved and the maintenance can be improved. (I.S.)

  12. Control rod experiments in Racine

    International Nuclear Information System (INIS)

    Stanculescu, A.; Humbert, G.

    1981-09-01

    A survey of the control-rod experiments planned within the joint CEA/CNEN-DeBeNe critical experiment RACINE is given. The applicability to both heterogeneous and homogeneous large power LMFBR-cores is discussed. Finally, the most significant results of the provisional design calculations performed on behalf of the RACINE control-rod programme are presented

  13. Control rod drives

    International Nuclear Information System (INIS)

    Kono, Nobuaki.

    1987-01-01

    Purpose: To remove movable portion and improve the reliability by the direct control to coil. Constitution: Coils are disposed vertically at a predetermined interval to the outside of a control rod drive guide tube and each of the coils is adapted to be directly controlled. The coils are arranged at such an interval that a plunger laps over the vertically adjacent coils. In the case of moving the plunger upwardly, a coil just above the coil that attract the plunger is energized while the coil attracting the plunger so far is denergized. Then, the plunger is pulled up to an aimed position by repeating the procedures. In the case of moving the plunger downwardly, the procedures are conducted in the manner opposite to the above. (Kawakami, Y.)

  14. Fuel rod for a reactor

    International Nuclear Information System (INIS)

    Tsuboi, Yoshiaki.

    1976-01-01

    Object: To accurately and simply measure gas pressure within a cladding tube of a fuel rod. Structure: The fuel rod is closed by an end plug with pellets made of uranium dioxide and a pressure detector element sealed into the cladding tube. When the fuel rod is manufactured, helium gases are introduced under pressure into the cladding tube, and the pressure detector element is contracted proportionally by the aforesaid pressure and therefore the amount of contract may be measured to thereby measure the inside pressure of the cladding tube. The amount of contract of the pressure detector element may be measured exteriorly of the fuel rod by arranging a fluorescent screen or film for X-rays or other radiations on one side of the fuel rod. (Yoshino, Y.)

  15. Control rod position detection device

    International Nuclear Information System (INIS)

    Akita, Haruo; Ogiwara, Sakae.

    1996-01-01

    The device of the present invention is used in a back-up shut down system of an LMFBR type reactor which is easy for maintenance, has high reliability and can recognize the position of control rods accurately. Namely, a permanent magnet is disposed to a control rod extension tube connected to the lower portion of the control rod. The detector guide tube is disposed in the vicinity of the control rod extension tube. A detector having a detection coil is inserted into a detector tube. With such constitution, the control rod can be detected at one position using the following method. (1) the movement of the magnetic field of the permanent magnet is detected by the detection coil. (2) a plurality of grooves are formed on the control rod extension tube, and the movement of the grooves is detected. In addition, the detection coil is inserted into the detector guide tube, and the signals from the detection coil are inputted to a signal processing circuit disposed at the outside of the reactor vessel using an MI cable to enable the maintenance of the detector. Further, if the detector comprises a detection coil and an excitation coil, the position of a dropped control rod can be recognized at a plurality of points. (I.S.)

  16. Spacers for fuel rod clusters

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1978-01-01

    The proposition deals with the fixing of nuclear fuel element rods in a grid which consists of a number of crossed Zy-plates which form cells. The rectangular cells have projections which serve as spacers for the fuel rods. According to the invention there are additional butt straps which can be moved in such a way that insertion and extraction of the fuel rods can be done without obstruction and they can be spring-loaded hold in their final position. (UWI) [de

  17. Control rod drives

    International Nuclear Information System (INIS)

    Sato, Takao; Arita, Setsuo; Mizuno, Katsuhiro.

    1986-01-01

    Purpose: To enable fine positioning by using an induction motor of a simple structure as a driving source and thereby improve the reliability of control rod drives. Constitution: A step actuator is directly coupled with an induction motor, in which the induction motor is connected by way of a pulse driving control circuit to an AC power source, while the step actuator is connected to a DC power source. When a thyristor is turned ON, the motor outputs a positive torque and rotates and starts to rotate in the forward direction. When the other thyristor is turned ON, the motor is applied with braking by a reverse excitation in a manner equivalent to the change for the exciting phase sequence. When the speed is lowered to a predetermined value, braking is actuated by the torque of the step actuator and the motor stops at a zero position or balanced position. In this way, braking is actuated from the decelerating step to the stopping with no abrasion and a highly accurate positioning is possible due to the characteristics of the step actuator. (Horiuchi, T.)

  18. Control rod drive

    International Nuclear Information System (INIS)

    Watando, Kosaku; Tanaka, Yuzo; Mizumura, Yasuhiro; Hosono, Kazuya.

    1975-01-01

    Object: To provide a simple and compact construction of an apparatus for driving a drive shaft inside with a magnetic force from the outside of the primary system water side. Structure: The weight of a plunger provided with an attraction plate is supported by a plunger lift spring means so as to provide a buffer action at the time of momentary movement while also permitting the load on lift coil to be constituted solely by the load on the drive shaft. In addition, by arranging the attraction plate and lift coil so that they face each other with a small gap there-between, it is made possible to reduce the size and permit efficient utilization of the attracting force. Because of the small size, cooling can be simply carried out. Further, since there is no mechanical penetration portion, there is no possibility of leakage of the primary system water. Furthermore, concentration of load on a latch pin is prevented by arranging so that with a structure the load of the control rod to be directly beared through the scrum latch. (Kamimura, M.)

  19. Nuclear reactor control rod

    International Nuclear Information System (INIS)

    Cearley, J.E.; Izzo, K.R.

    1987-01-01

    This patent describes a vertically oriented bottom entry control rod from a nuclear reactor: a frame including an elongated central spine of cruciform cross section connected between an upper support member and a lower support member both of cruciform shape having four laterally extending arms. The arms are in alignment with the arms of the lower support member and each aligned upper and lower support members has a sheath extending between; absorber plates of neutron absorber material, different from the material of the frame, one of the absorber plates is positioned within a sheath beneath each of the arms; attachment means suspends the absorber plates from the arms of the upper support member within a sheath; elongated absorber members positioned within a sheath between each of the suspended absorber plates and an arm of the lower support member; and joint means between the upper ends of the absorber members and the lower ends of the suspended absorber plates for minimizing gaps; the sheath means encloses the suspended absorber plates and the absorber members extending between aligned arms of the upper and lower support members and secured

  20. Synthesis of beta carbon nitride nanosized crystal through mechanochemical reaction

    CERN Document Server

    Yin Long Wei; Liu Yu Xian; Sui Jin Ling; Wang Jing Min

    2003-01-01

    Nanosized beta carbon nitride (beta-C sub 3 N sub 4), of grain size several tens of nanometres, has been synthesized by mechanochemical reaction processing. The low-cost synthetic method developed facilitates the novel and effective synthesis of nanosized crystalline beta-C sub 3 N sub 4 (a = 6.36 A, c = 4.648 A) powders. The graphite powders were first milled to a nanoscale state, then the nanosized graphite powders were milled in an atmosphere of NH sub 3 gas. It was found that nanosized beta-C sub 3 N sub 4 was formed after high-energy ball milling under an NH sub 3 atmosphere. After thermal annealing, the shape of the beta-C sub 3 N sub 4 changes from flake-like to sphere-like. The nanosized beta-C sub 3 N sub 4 formed was characterized by x-ray diffraction, Fourier transformation infrared spectroscopy, and transmission electron microscopy. A solid-gas reaction mechanism was proposed for the formation of nanosized beta-C sub 3 N sub 4 at room temperature induced by mechanochemical activation.

  1. Synthesis and characterization of nanosize sodium titanates

    Energy Technology Data Exchange (ETDEWEB)

    Elvington, M. C.; Tosten, M.; Taylor-Pashow, K. M. L.; Hobbs, D. T., E-mail: david.hobbs@srnl.doe.gov [Savannah River National Laboratory (United States)

    2012-11-15

    This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST). The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST). Key modifications to this process include altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150 nm. The BET surface area and isoelectric point of the nMST measured 285 m{sup 2} g{sup -1} and 3.34 pH units, respectively, which is more than an order of magnitude higher in surface area and a pH unit lower than that measured for the microsize MST. The nMST material serves as an effective ion exchanger under both weakly acidic and strongly alkaline conditions and was converted to a peroxotitanate form by reaction with hydrogen peroxide.

  2. Means for driving control rod

    International Nuclear Information System (INIS)

    Sato, Haruo; Sasaki, Masayoshi.

    1974-01-01

    Object: To enable wire rope to be readily removed from guide pulleys for the inspection or replacement of control rods. Structure: A pair of guide pulleys disposed to oppose each other are provided on their periphery with respective notches which are arranged in a staggered fashion. In this way, the rope is made to be removed from the notches for inspection of the control rod or for other purposes. (Kamimura, M.)

  3. Simulation of leaking fuel rods

    International Nuclear Information System (INIS)

    Hozer, Z.

    2006-01-01

    The behaviour of failed fuel rods includes several complex phenomena. The cladding failure initiates the release of fission product from the fuel and in case of large defect even urania grains can be released into the coolant. In steady state conditions an equilibrium - diffusion type - release is expected. During transients the release is driven by a convective type leaching mechanism. There are very few experimental data on leaking WWER fuel rods. For this reason the activity measurements at the nuclear power plants provide very important information. The evaluation of measured data can help in the estimation of failed fuel rod characteristics and the prediction of transient release dynamics in power plant transients. The paper deals with the simulation of leaking fuel rods under steady state and transient conditions and describes the following new results: 1) A new algorithm has been developed for the simulation of leaking fuel rods under steady state conditions and the specific parameters of the model for the Paks NPP has been determined; 2) The steady state model has been applied to calculation of leaking fuel characteristics using iodine and noble gas activity measurement data; 3) A new computational method has been developed for the simulation of leaking fuel rods under transient conditions and the specific parameters for the Paks NPP has been determined; 4) The transient model has been applied to the simulation of shutdown process at the Paks NPP and for the prediction of the time and magnitude of 123 I activity peak; 5) Using Paks NPP data a conservative value has been determined for the upper limit of the 123 I release from failed fuel rods during transients

  4. Preparation and performance of nanosized tungsten carbides for electrocatalysis

    International Nuclear Information System (INIS)

    Shen Peikang; Yin Shibin; Li Zihui; Chen Chan

    2010-01-01

    The principle of the intermittent microwave heating (IMH) method and the details on the working procedure for prepare nanosized materials were presented along with the comparison to the traditional continuous microwave heating (CMH) method. The nanosized tungsten carbides were synthesized as an example by this novel method. It produced WC with the average particle size of 21.4 nm at the procedure of 15 s-on and 15 s-off for 20 times, however, the particle size increased to 35.7 nm by CMH method for 5 min. The pure WC was obtained by post-treating the sample in NaOH solution, which gave the better performance as support. The nanosized WC was used as support for the Pt nanoparticles (Pt-WC/C(IMH)) for alcohol oxidation and oxygen reduction. It was proved that the Pt-WC/C(IMH) electrocatalysts gave the better performance than that prepared by CMH method (Pt-WC/C(CMH)) or Pt/C electrocatalysts in terms of the activity and CO-tolerance. The intermittent microwave heating method is easier to scale-up for mass production of the nanosized tungsten carbides and other nanosized materials as well.

  5. The Third ATLAS ROD Workshop

    CERN Multimedia

    Poggioli, L.

    A new-style Workshop After two successful ATLAS ROD Workshops dedicated to the ROD hardware and held at the Geneva University in 1998 and in 2000, a new style Workshop took place at LAPP in Annecy on November 14-15, 2002. This time the Workshop was fully dedicated to the ROD-TDAQ integration and software in view of the near future integration activities of the final RODs for the detector assembly and commissioning. More precisely, the aim of this workshop was to get from the sub-detectors the parameters needed for T-DAQ, as well as status and plans from ROD builders. On the other hand, what was decided and assumed had to be stated (like EB decisions and URDs), and also support plans. The Workshop gathered about 70 participants from all ATLAS sub-detectors and the T-DAQ community. The quite dense agenda allowed nevertheless for many lively discussions, and for a dinner in the old town of Annecy. The Sessions The Workshop was organized in five main sessions: Assumptions and recommendations Sub-de...

  6. Reactor control rod supporting structure

    International Nuclear Information System (INIS)

    Akimoto, Tokuzo; Miyata, Hiroshi.

    1984-01-01

    Purpose: To enable stable reactor core control even in extremely great vertical earthquakes, as well as under normal operation conditions in FBR type reactors. Constitution: Since a mechanism for converting the rotational movement of a control rod into vertical movement is placed at the upper portion of the reactor core at high temperature, the mechanism should cause fusion or like other danger after the elapse of a long period of time. In view of the above, the conversion mechanism is disposed to the lower portion of the reactor core at a lower temperature region. Further, the connection between the control rod and the control rod drive can be separated upon great vertical earthquakes. (Seki, T.)

  7. Advanced gray rod control assembly

    Energy Technology Data Exchange (ETDEWEB)

    Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O

    2013-09-17

    An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.

  8. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    1993-05-01

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 2 discusses the following topics: Fuel Rod Extraction System Test Results and Analysis Reports and Clamping Table Test Results and Analysis Reports

  9. Lateral Penetration of a Rod

    Science.gov (United States)

    Alston, James; Bless, Stephan; Subramanian, Ravi

    2002-03-01

    Penetration of yawed rods remains one of the outstanding problems in terminal ballistics. An essential feature of yawed rod penetration is the interaction of the shank of the projectile with the side of the penetration cavity. A two-dimensional finite difference code was used to solve this problem for the case of a projectile with a circular cross section penetrating armor steel. This case is particularly relevant for the problem of a high velocity high density rod penetrating a finite plate. The force exerted by the target on the projectile was determined as a function of embedment depth and lateral velocity. The solution was verified by checking the centerline pressure against the closed form solution for cylindrical cavity expansion

  10. Maximum/minimum asymmetric rod detection

    International Nuclear Information System (INIS)

    Huston, J.T.

    1990-01-01

    This patent describes a system for determining the relative position of each control rod within a control rod group in a nuclear reactor. The control rod group having at least three control rods therein. It comprises: means for producing a signal representative of a position of each control rod within the control rod group in the nuclear reactor; means for establishing a signal representative of the highest position of a control rod in the control rod group in the nuclear reactor; means for establishing a signal representative of the lowest position of a control rod in the control rod group in the nuclear reactor; means for determining a difference between the signal representative of the position of the highest control rod and the signal representative of the position of the lowest control rod; means for establishing a predetermined limit for the difference between the signal representative of the position of the highest control rod and the signal representative of the position of the lowest control rod; and means for comparing the difference between the signals with the predetermined limit. The comparing means producing an output signal when the difference between the signals exceeds the predetermined limit

  11. Preparation of nanosized non-oxide powders using diatomaceous earth

    Directory of Open Access Journals (Sweden)

    Šaponjić A.

    2009-01-01

    Full Text Available In this paper the nanosized non-oxide powders were prepared by carbothermal reduction and subsequent nitridation of diatomaceous earth which is a waste product from coal exploitation. Our scope was to investigate the potential use of diatomaceous earth as a main precursor for low-cost nanosized non-oxide powder preparation as well as to solve an environmental problem. The influence of carbon materials (carbonized sucrose, carbon cryogel and carbon black as a reducing agent on synthesis and properties of low-cost nanosized nonoxide powders was also studied. The powders were characterized by specific surface area, X-ray and SEM investigations. It was found that by using diatomaceous earth it is was possible to produce either a mixture of non-oxide powders (Si3N4/SiC or pure SiC powders depending on temperature.

  12. Control rod housing alignment apparatus

    International Nuclear Information System (INIS)

    Dixon, R.C.; Deaver, G.A.; Punches, J.R.; Singleton, G.E.; Erbes, J.G.; Offer, H.P.

    1991-01-01

    This paper discusses an alignment device for precisely locating the position of the top of a control rod drive housing from an overlying and corresponding hole and alignment pin in a core plate within a boiling water nuclear reactor. It includes a shaft, the shaft having a length sufficient to extend from the vicinity of the top of the control rod drive housing up to and through the hole in the core plate; means for registering the top of the shaft to the hole in the core plate, the registering means including means for registering with an alignment pin in the core plate adjacent the hole

  13. Morphological, Structural, and Electrical Characterization of Sol-Gel-Synthesized ZnO Nano rods

    International Nuclear Information System (INIS)

    Kashif, M.; Hashim, U.; Foo, K.L.; Ali, M.E.; Ali, M.E.; Ali, S.M.U.

    2013-01-01

    ZnO nano rods were grown on thermally oxidized p-type silicon substrate using sol-gel method. The SEM image revealed high-density, well-aligned, and perpendicular ZnO nano rods on the oxidized silicon substrate. The XRD profile confirmed the c-axis orientation of the nano rods. PL measurements showed the synthesized ZnO nano rods have strong ultraviolet (UV) emission. The electrical characterization was performed using interdigitated silver electrodes to investigate the stability in the current flow of the fabricated device under different ultraviolet (UV) exposure times. It was notified that a stable current flow was observed after 60 min of UV exposure. The determination of stable current flow after UV exposure is necessary for UV-based gas sensing and optoelectronic devices.

  14. Mn3O4 nano-sized crystals: Rapid synthesis and extension to ...

    Indian Academy of Sciences (India)

    to preparation of nanosized LiMn2O4 materials. XIAO-LING CUI ... applications such as magnetic storage media, catalysis, electrodes, ion .... of ethanol. After similar processes with the rapid prepa- ration of nano-sized Mn3O4 crystals, a black colloidal solution containing nano-sized Mn3O4 crystals and the preferred lithium ...

  15. Flow resistance in rod assemblies

    International Nuclear Information System (INIS)

    Korsun, A.S.; Sokolova, M.S.

    2000-01-01

    The general form of relation between the resistance force and the velocity vector, resistance tensor structure and possible types of anisotropy in the flow thorough such structures as rod or tube assemblies are under discussion. Some questions of experimental determination of volumetric resistance force tensor are also under consideration. (author)

  16. Control rod removal blocking device

    International Nuclear Information System (INIS)

    Yoshioka, Ritsuo.

    1981-01-01

    Purpose: To prevent excess power increase resulted from erroneous control rod removal during high power operation in BWR type reactor by decreasing the continuous removal enabling distance for the control rods along with increase in the reactor power where the reactor power is greater than a predetermined level. Constitution: When control rod selection signals are supplied from a control unit to a control rod removal blocking device, the blocking device judges whether the reactor core power is greater than a predetermined value A or not, using reactor core power signals outputted from an average power monitor. Where the reactor core power exceeds the predetermined value A and if the reactor core power is relatively low, a large continuous removal enabling distance N 1 is calculated in the blocking device to allow the continuous removal as far as the notch N 1 . The continuous removal enabling distance is shortened as the reactor core power increases and the removal is blocked, for example, at notch N 2 . While on the other hand, if the reactor core power is below the predetermined value A, both of the notchwise removal and the continuous removal are enabled. (Seki, T.)

  17. Control rod behaviour in earthquakes

    International Nuclear Information System (INIS)

    Kawakami, S.; Akiyama, H.; Shibata, H.; Watabe, M.; Ichikawa, T.; Fujita, K.

    1990-01-01

    For some years the Japanese have been working on a major research programme to determine the likely effects of an earthquake on nuclear plant internals. One aspect of this was a study of the behaviour of Pressurized Water Reactor control rods as they are being inserted in the core, which is reported here. (author)

  18. Nuclear fuel rod loading apparatus

    International Nuclear Information System (INIS)

    King, H.B.

    1981-01-01

    A nuclear fuel loading apparatus, incorporating a microprocessor control unit, is described which automatically loads nuclear fuel pellets into dual fuel rods with a minimum of manual involvement and in a manner and sequence to ensure quality control and accuracy. (U.K.)

  19. Inspection system for Zircaloy clad fuel rods

    International Nuclear Information System (INIS)

    Yancey, M.E.; Porter, E.H.; Hansen, H.R.

    1975-10-01

    A description is presented of the design, development, and performance of a remote scanning system for nondestructive examination of fuel rods. Characteristics that are examined include microcracking of fuel rod cladding, fuel-cladding interaction, cladding thickness, fuel rod diameter variation, and fuel rod bowing. Microcracking of both the inner and outer fuel rod surfaces and variations in wall thickness are detected by using a pulsed eddy current technique developed by Argonne National Laboratory (ANL). Fuel rod diameter variation and fuel rod bowing are detected by using two linear variable differential transformers (LVDTs) and a signal conditioning system. The system's mechanical features include variable scanning speeds, a precision indexing system, and a servomechanism to maintain proper probe alignment. Initial results indicate that the system is a very useful mechanism for characterizing irradiated fuel rods

  20. Duke Power Company's control rod wear program

    International Nuclear Information System (INIS)

    Culp, D.C.; Kitlan, M.S. Jr.

    1990-01-01

    Recent examinations performed at several foreign and domestic pressurized water reactors have identified significant control rod cladding wear, leading to the conclusion that previously believed control rod lifetimes are not attainable. To monitor control rod performance and reduce safety concerns associated with wear, Duke Power Company has developed a comprehensive control rod wear program for Ag-In-Cd and boron carbide (B 4 C) rods at the McGuire and Catawba nuclear stations. Duke Power currently uses the Westinghouse 17 x 17 Ag-In-Cd control rod design at McGuire Unit 1 and the Westinghouse 17 x 17 hybrid B 4 C control rod design with a Ag-In-Cd tip at McGuire Unit 2 and Catawba Units 1 and 2. The designs are similar, with the exception of the absorber material and clad thickness. There are 53 control rods per unit

  1. Neocellularization and neovascularization of nanosized bioactive glass-coated decellularized trabecular bone scaffolds

    KAUST Repository

    Gerhardt, Lutz Christian

    2012-09-11

    In this study, the in vivo recellularization and neovascularization of nanosized bioactive glass (n-BG)-coated decellu-larized trabecular bone scaffolds were studied in a rat model and quantified using stereological analyses. Based on the highest amount of vascular endothelial growth factor (VEGF) secreted by human fibroblasts grown on n-BG coatings (0-1.245 mg/cm 2), decellularized trabecular bone samples (porosity: 43-81%) were coated with n-BG particles. Grown on n-BG particles at a coating density of 0.263 mg/cm2, human fibroblasts produced 4.3 times more VEGF than on uncoated controls. After 8 weeks of implantation in Sprague-Dawley rats, both uncoated and n-BG-coated samples were well infiltrated with newly formed tissue (47-48%) and blood vessels (3-4%). No significant differences were found in cellularization and vascularization between uncoated bone scaffolds and n-BG-coated scaffolds. This finding indicates that the decellularized bone itself may exhibit growth-promoting properties induced by the highly interconnected pore microarchitecture and/or proteins left behind on decellularized scaffolds. Even if we did not find proangiogenic effects in n-BG-coated bone scaffolds, a bioactive coating is considered to be beneficial to impart osteoinductive and osteoconductive properties to decellularized bone. n-BG-coated bone grafts have thus high clinical potential for the regeneration of complex tissue defects given their ability for recellularization and neovascularization. © 2012 Wiley Periodicals, Inc.

  2. Solid-state-laser-rod holder

    Science.gov (United States)

    Gettemy, D.J.; Barnes, N.P.; Griggs, J.E.

    1981-08-11

    The disclosure relates to a solid state laser rod holder comprising Invar, copper tubing, and epoxy joints. Materials and coefficients of expansion of the components of the holder combine with the rod to produce a joint which will give before the rod itself will. The rod may be lased at about 70 to 80/sup 0/K and returned from such a temperature to room temperature repeatedly without its or the holder's destruction.

  3. Screen printed nanosized ZnO thick film

    Indian Academy of Sciences (India)

    Unknown

    BINDU KRISHNAN* and V P N NAMPOORI†. Centre for Materials for Electronics Technology, Athani P O, Thrissur 680 771, India. †International School of Photonics, Cochin University of Science and Technology, Cochin 682 022, India. MS received 6 November 2004; revised 5 March 2005. Abstract. Nanosized ZnO was ...

  4. Crystallization of Organic Semiconductor Molecules in Nanosized Cavities

    DEFF Research Database (Denmark)

    Milita, Silvia; Dionigi, Chiara; Borgatti, Francesco

    2008-01-01

    The crystallization of an organic semiconductor, viz., tetrahexil-sexithiophene (H4T6) molecules, confined into nanosized cavities of a self-organized polystyrene beads template, has been investigated by means of in situ grazing incidence X-ray diffraction measurements, during the solvent...

  5. Synthesis of nanosized silver colloids by microwave dielectric heating

    Indian Academy of Sciences (India)

    Silver nanosized crystallites have been synthesized in aqueous and polyols viz., ethylene glycol and glycerol, using a microwave technique. Dispersions of colloidal silver have been prepared by the reduction of silver nitrate both in the presence and absence of stabilizer poly(vinylpyrolidone) (PVP). It was observed that ...

  6. Modification of unsaturated polyester resins using nano-size core ...

    African Journals Online (AJOL)

    Modification of unsaturated polyester resins using nano-size core-shell particles. MO Munyati, PA Lovell. Abstract. No Abstract Available Journal of Science and Technology Special Edition 2004: 24-31. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  7. Magnetic properties of hexaferrite nanosized powders produced via mechanoactivation

    Directory of Open Access Journals (Sweden)

    Naiden E.P.

    2005-01-01

    Full Text Available A study of the relationship between structural parameters and principal magnetic characteristics of nanosized powders of hexagonal ferrimagnetics produced via mechanoactivation has been carried out. The models describing the influence of the size effects on temperatures of magnetic phase transformations, saturation magnetization and magnetic anisotropy of similar materials are discussed.

  8. Mössbauer and magnetization studies of nanosize chromium ferrite ...

    African Journals Online (AJOL)

    Nanosize chromium ferrite (CrF) powder samples were synthesized by citrate precursor route in the size range of 6 to 35 nm. The structural and magnetic behaviour of these samples were studied using X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Mössbauer spectroscopic techniques. Synthesized ...

  9. Nanosize boride particles in heat-treated nickel base superalloys

    International Nuclear Information System (INIS)

    Zhang, H.R.; Ojo, O.A.; Chaturvedi, M.C.

    2008-01-01

    Grain boundary microconstituents in aged nickel-based superalloys were studied by transmission electron microscopy techniques. A nanosized M 5 B 3 boride phase, possibly formed by intergranular solute desegregation-induced precipitation, was positively identified. The presence of these intergranular nanoborides provides reasonable clarification of a previously reported reduction of grain boundary liquation temperature during the weld heat affected zone thermal cycle

  10. Membrane with Stable Nanosized Microstructure and Method for Producing same

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a membrane, comprising in this order a first catalyst layer, an electronically and ionically conducting layer having a nanosized microstructure, and a second catalyst layer, characterized in that the electronically and ionically conducting layer is formed from an el...... an electrolyte material, a grain growth inhibitor and/or grain boundary modifier, and a method for producing same....

  11. Strengthening Effect of Extruded Mg-8Sn-2Zn-2Al Alloy: Influence of Micro and Nano-Size Mg2Sn Precipitates

    Science.gov (United States)

    Cheng, Weili; Bai, Yang; Wang, Lifei; Wang, Hongxia; Bian, Liping; Yu, Hui

    2017-01-01

    In this study, Mg-8Sn-2Zn-2Al (TZA822) alloys with varying Mg2Sn contents prior to extrusion were obtained by different pre-treatments (without and with T4), and the strengthening response related to micro and nano-size Mg2Sn precipitates in the extruded TZA822 alloys was reported. The results showed that the morphology of nano-size Mg2Sn precipitates exhibits a significant change in basal plane from rod-like to spherical, owing to the decrement in the fraction of micro-size particles before extrusion. Meanwhile, the spherical Mg2Sn precipitates provided a much stronger strengthening effect than did the rod-like ones, which was ascribed to uniform dispersion and refinement of spherical precipitates to effectively hinder basal dislocation slip. As a consequence, the extruded TZA822 alloy with T4 showed a higher tensile yield strength (TYS) of 245 MPa, ultimate tensile strength (UTS) of 320 MPa and elongation (EL) of 26.5%, as well as a lower degree of yield asymmetry than their counterpart without T4. Detailed reasons for the strengthening effect were given and analyzed. PMID:28773180

  12. Process and apparatus for controlling control rods

    International Nuclear Information System (INIS)

    Gebelin, B.; Couture, R.

    1987-01-01

    This process and apparatus is characterized by 2 methods, for examination of cluster of nuclear control rods. Foucault current analyzer which examines fraction by fraction all the control rods. This examination is made by rotation of the cluster. Doubtful rods are then analysed by ultrasonic probe [fr

  13. ELECTRIC FIELD MEASUREMENT IN ROD-DISCONTINUED ...

    African Journals Online (AJOL)

    2014-06-30

    Jun 30, 2014 ... the electrogeometrical model using a laboratory experimental rod-plane air gap arrangement with a lightning conductor (Franklin rod or horizontal conductor). The stepped leader could be represented by the rod electrode under a negative lightning impulse voltage having a level leading to breakdown with ...

  14. Spider and burnable poison rod combinations

    International Nuclear Information System (INIS)

    Edwards, G.T.; Schluderberg, D.C.

    1980-01-01

    An improved design of burnable poison rods and associated spiders used in fuel assemblies of pressurized water power reactor cores, is described. The rods are joined to the spider arms in a manner which is proof against the reactor core environment and yet allows the removal of the rods from the spider simply, swiftly and delicately. (U.K.)

  15. Testing device for control rod drives

    International Nuclear Information System (INIS)

    Hayakawa, Toshifumi.

    1992-01-01

    A testing device for control rod drives comprises a logic measuring means for measuring an output signal from a control rod drive logic generation circuit, a control means for judging the operation state of a control rod and a man machine interface means for outputting the result of the judgement. A driving instruction outputted from the control rod operation device is always monitored by the control means, and if the operation instruction is stopped, a testing signal is outputted to the control rod control device to simulate a control rod operation. In this case, the output signal of the control rod drive logic generation circuit is held in a control rod drive memory means and intaken into a logic analysis means for measurement and an abnormality is judged by the control means. The stopping of the control rod drive instruction is monitored and the operation abnormality of the control rod is judged, to mitigate the burden of an operator. Further, the operation of the control rod drive logic generation circuit can be confirmed even during a nuclear plant operation by holding the control rod drive instruction thereby enabling to improve maintenance efficiency. (N.H.)

  16. Solitary waves on nonlinear elastic rods. II

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.

    1987-01-01

    In continuation of an earlier study of propagation of solitary waves on nonlinear elastic rods, numerical investigations of blowup, reflection, and fission at continuous and discontinuous variation of the cross section for the rod and reflection at the end of the rod are presented. The results...

  17. Rod and lamellar growth of eutectic

    Directory of Open Access Journals (Sweden)

    M. Trepczyńska-Łent

    2010-04-01

    Full Text Available The paper presents adaptation problem of lamellar growth of eutectic. The formation of rod eutectic microstructure was investigated systematically. A new rod eutectic configuration was observed in which the rods form with elliptical cylindrical shape. A new interpretation of the eutectic growth theory was proposed.

  18. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    Science.gov (United States)

    Young, J.N.

    1958-04-22

    An electromagnetic apparatus for moving a rod-like member in small steps in either direction is described. The invention has particular application in the reactor field where the reactor control rods must be moved only a small distance and where the use of mechanical couplings is impractical due to the high- pressure seals required. A neutron-absorbing rod is mounted in a housing with gripping uaits that engage the rod, and coils for magnetizing the gripping units to make them grip, shift, and release the rod are located outside the housing.

  19. Snubber assembly for a control rod drive

    International Nuclear Information System (INIS)

    Matthews, J.C.

    1978-01-01

    A snubber cartridge assembly is mounted to the nozzle of a control rod drive mechanism to insure that the snubber assembly will be located within the liquid filled section of a nuclear reactor vessel whenever the control rod drive is assembled thereto. The snubber assembly includes a piston mounted proximate to the control rod connecting end of the control rod drive leadscrew to allow the piston to travel within the liquid filled snubber cartridge and controllably exhaust liquid therefrom during a ''scram'' condition. The snubber cartridge provides three separate areas of increasing resistance to piston travel to insure a speedy but safe ''scram'' of the control rod into the reactor

  20. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    1993-05-01

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 1 discusses the following topics: the background of the project; test program description; summary of tests and test results; problem evaluation; functional requirements confirmation; recommendations; and completed test documentation for tests performed in Phase 3

  1. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    1993-05-01

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 9 discusses the following topics: Integrated System Normal Operations Test Results and Analysis Report; Integrated System Off-Normal Operations Test Results and Analysis Report; and Integrated System Maintenance Operations Test Results and Analysis Report

  2. Fuel rod assembly to manifold attachment

    Science.gov (United States)

    Donck, Harry A.; Veca, Anthony R.; Snyder, Jr., Harold J.

    1980-01-01

    A fuel element is formed with a plurality of fuel rod assemblies detachably connected to an overhead support with each of the fuel rod assemblies having a gas tight seal with the support to allow internal fission gaseous products to flow without leakage from the fuel rod assemblies into a vent manifold passageway system on the support. The upper ends of the fuel rod assemblies are located at vertically extending openings in the support and upper threaded members are threaded to the fuel rod assemblies to connect the latter to the support. The preferred threaded members are cap nuts having a dome wall encircling an upper threaded end on the fuel rod assembly and having an upper sealing surface for sealing contact with the support. Another and lower seal is achieved by abutting a sealing surface on each fuel rod assembly with the support. A deformable portion on the cap nut locks the latter against inadvertent turning off the fuel rod assembly. Orienting means on the fuel rod and support primarily locates the fuel rods azimuthally for reception of a deforming tool for the cap nut. A cross port in the fuel rod end plug discharges into a sealed annulus within the support, which serves as a circumferential chamber, connecting the manifold gas passageways in the support.

  3. Control-rod scram device

    International Nuclear Information System (INIS)

    Matsui, Yoshiro; Saito, Koji.

    1986-01-01

    Purpose: To eliminate the requirement for the nitrogen gas system in a scram device and enable safety and reliable shutdown of a water-cooled reactor power plant. Constitution: A piston and a spring are contained within a hydraulic vessel, and the piston is driven by the energy stored in the spring so as to supply hydraulic water to control mechanisms. During usual reactor operation, a scram valve is closed and a high water pressure of about 130 kg/cm 2 is applied to the water filled in the vessel through a check valve. Upon occurrence of abnormal conditions and generation of scram signals, the scram valve is opened to supply the water filled in the vessel through the scram valve to the control rod drive mechanisms. When the water pressure in the vessel is decreased, since the piston is urged upwardly by the energy stored in the spring, the water filled in the vessel is intermitently supplied to the control rod drive mechanisms. Thus, control rods can be inserted into the nuclear reactor to shutdown the same. (Horiuchi, T.)

  4. Fuel rod and fuel assembly

    International Nuclear Information System (INIS)

    Takekawa, Tetsuya.

    1993-01-01

    Burnable poisons are contained in a portion of a pellet constituting a fuel rod. A distribution density of the burnable poison-containing pellets and a concentration of the burnable poisons in the pellet are varied depending on the axial position of the fuel rod. That is, the distribution density of the burnable poison containing-pellets is increased at the central portion of the fuel rod and it is decreased at both ends thereof, and a concentration of the burnable poisons of the burnable poison containing-pellet disposed at the end portions thereof is decreased to less than a concentration of the burnable poison-containing pellet at the central portion. With such a constitution, a central peaking at an early stage of the combustion cycle is decreased. Accordingly, power at the central portion is increased than that in the end portions at the latter half of the cycle, to flatten the power distribution. Further, a burnable poison concentration of the pellets at the end portions is decreased to promote burning of burnable poisons at the end portions which are less burnable relatively, thereby enabling to prevent worsening of neutron economy. (T.M.)

  5. Wear Resistance of Austempered Ductile Iron with Nanosized Additives

    Science.gov (United States)

    Kaleicheva, J. K.; Mishev, V.

    2018-01-01

    The wear resistance, microstructure and mechanical properties of austempered ductile iron (ADI) with nanosized additives of cubic boron nitride cBN are investigated. Samples of ductile iron are put under austhempering at the following conditions: heating at 900°С, 1 h and isothermal retention at 280оС, 2 h and 380°С, 2 h with the aim to achieve a lower bainitic structure and an upper bainitic structure. The experimental wear testing of austempered ductile irons is performed in friction conditions of a fixed abrasive by a cinematic scheme „pin - disc” using an accelerated testing method and device. The microstructure of the ADI is investigated by metallographic and X-Ray analyses. The Vickers hardness testing and impact strength examination are carried out. The influence of the nanosized additives of cBN on the wear resistance, microstructure, impact strength and hardness of the ADI is investigated.

  6. Cellular detonations in nano-sized aluminum particle gas suspensions

    Science.gov (United States)

    Khmel, TA

    2017-10-01

    Formation of cellular detonation structures in monodisperse nano-sized aluminum particle – oxygen suspensions is studied by methods of numerical simulations of two-dimensional detonation flows. The detonation combustion are described within the semi-empirical model developed earlier which takes into account transition of the regime of aluminum particle combustion from diffusion to kinetic for micro-sized and nano-sized particles. The free-molecular effects are considered in the processes of heat and velocity relaxation of the phases. The specific features of the cellular detonation of nanoparticle suspensions comparing with micron-sized suspensions are irregular cellular structures, much higher pick pressure values, and relatively larger detonation cells. This is due to high value of activation energy of reduced chemical reaction of aluminum particle combustion in kinetic regime.

  7. Structural and magnetic properties of mechanochemically synthesized nanosized yttrium titanate

    Directory of Open Access Journals (Sweden)

    Barudžija Tanja

    2012-01-01

    Full Text Available Nanosized perovskite YTiO3 with the mean crystallite size of 18 nm was synthesized for the first time by mechanochemical treatment. The mechanochemical solid state reaction between commercial Y2O3 powder and mechanochemically synthesized TiO powder in molar ratio 0.5:1 was completed for 3 h in a high-energy planetary ball mill in argon atmosphere. The heating in vacuum at 1150 °C for 12 h transforms nanosized YTiO3 to a well-crystallized single-phase perovskite YTiO3. Both samples were characterized by X-ray diffraction (XRD and thermogravimetric (TGA/DTA analyses, as well as superconducting quantum interference device magnetometer (SQUID measurements.

  8. Vibrational characteristics and wear of fuel rods

    International Nuclear Information System (INIS)

    Schmugar, K.L.

    1977-01-01

    Fuel rod wear, due to vibration, is a continuing concern in the design of liquid-cooled reactors. In my report, the methodology and models that are used to predict fuel rod vibrational response and vibratory wear, in a light water reactor environment, are discussed. This methodology is being followed at present in the design of Westinghouse Nuclear Fuel. Fuel rod vibrations are expressed as the normal bending modes, and sources of rod vibration are examined with special emphasis on flow-induced mechanisms in the stable flow region. In a typical Westinghouse PWR fuel assembly design, each fuel rod is supported at multiple locations along the rod axis by a square-shaped 'grid cell'. For a fuel rod /grid support system, the development of small oscillatory motions, due to fluid flow at the rod/grid interface, results in material wear. A theoretical wear mode is developed using the Archard Theory of Adhesive Wear as the basis. Without question certainty, fretting wear becomes a serious problem if it progresses to the stage where the fuel cladding is penetrated and fuel is exposed to the coolant. Westinghouse fuel is designed to minimize fretting wear by limiting the relative motion between the fuel rod and its supports. The wear producing motion between the fuel rod and its supports occurs when the vibration amplitude exceeds the slippage threshold amplitude

  9. Raman scattering in nanosized nickel oxide NiO

    International Nuclear Information System (INIS)

    Mironova-Ulmane, N; Kuzmin, A; Steins, I; Grabis, J; Sildos, I; Paers, M

    2007-01-01

    Magnetic ordering in nanosized (100 and 1500 nm) nickel oxide NiO powders, prepared by the plasma synthesis method, was studied using Raman scattering spectroscopy in a wide range of temperatures from 10 to 300 K. It was observed that the intensity of two-magnon band decreases rapidly for smaller crystallites size. This effect is attributed to a decrease of antiferromagnetic spin correlations and leads to the antiferromagnetic-to-paramagnetic phase transition

  10. Electrical and Optical Properties of Nanosized Perovskite-type La ...

    African Journals Online (AJOL)

    Electrical and Optical Properties of Nanosized Perovskite-type La 0.5 Ca 0.5 MO 3 (M=Co,Ni) prepared using a Sol-Gel Method. ... calculate the absorption coefficient (α) as a function of photon energy (hυ) and the obtained results indicate that the optical band gap energy (Eg) for LCNO sample is smaller than that of LCCO.

  11. Superconducting film magnetic flux transformer with micro- and nanosized branches

    Directory of Open Access Journals (Sweden)

    Levan Ichkitidze

    2013-06-01

    Full Text Available The object of the study is a superconducting film magnetic flux transformer comprising two square shaped loops with the tapering active strips and a magnetosensitive film element between them. It is shown that splitting of the active strips into parallel micro- and nanosized superconducting branches and slits increases the gain factor of the transformer, i. e., the concentration of an external magnetic field on the magnetosensitive element, by a factor of more than four.

  12. Strong enhancement of superconductivity in a nanosized Pb bridge

    OpenAIRE

    Misko, V. R.; Fomin, V. M.; Devreese, J. T.

    2000-01-01

    In recent experiments with a superconducting nanosized Pb bridge formed between a scanning tunneling microscope tip and a substrate, superconductivity has been detected at magnetic fields, which are few times larger than the third (surface) critical field. We describe the observed phenomenon on the basis of a numerical solution of the Ginzburg-Landau equations in a model structure consisting of six conoids. The spatial distribution of the superconducting phase is shown to be strongly inhomoge...

  13. Wear Behavior of Austempered Ductile Iron with Nanosized Additives

    Directory of Open Access Journals (Sweden)

    J. Kaleicheva

    2014-03-01

    Full Text Available The microstructure and properties of austempered ductile iron (ADI strengthened with nanosized addtives of titanium nitride + titanium carbonitride (TiN + TiCN, titanium nitride TiN and cubic boron nitride cBN are investigated. The TiN, TiCN and cBN, nanosized particles are coated by electroless nickel coating EFTTOM-NICKEL prior to the edition to the melt. The spheroidal graphite iron samples are undergoing an austempering, including heating at 900 оС for an hour, after that isothermal retention at 280 оС, 2 h and 380 оС, 2h. The metallographic analysis by optical metallographic microscope GX41 OLIMPUS and hardness measurements by Vickers Method are performed. The structure of the austempered ductile iron consists of lower bainite and upper bainite.Experimental investigation of the wear by fixed abrasive are also carried out. The influence of the nanosized additives on the microstructure, mechanical and tribological properties of the austempered ductile irons (ADI is studied.

  14. High temperature control rod assembly

    Science.gov (United States)

    Vollman, Russell E.

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  15. Control rod for a reactor

    International Nuclear Information System (INIS)

    Natori, Hisahide.

    1975-01-01

    Object: To change arrangement and density of each layer of neutron absorber in the control rod and to render rotation by each layer possible, whereby the neutron absorber may be rotated to readily flatten power distribution. Structure: Neutron absorbers such as boron and carbide are filled into stainless steel pipes, which are peripherally arranged in a multi-layer fashion. Arrangement and density of the neutron absorber by each layer are changed and rotation by each layer is made possible, whereby surface area of the absorber or the like is changed to flatten power distribution. (Furukawa, Y.)

  16. Laboratory experiments with impacting fuel rods

    International Nuclear Information System (INIS)

    Kiss, S.; Lipcsei, S.

    1994-10-01

    Vibration surveillance and diagnostics of fuel rods and fuel assemblies are important tasks in NPPs. Thus accurate knowledge of vibration phenomena and measurability is very important. Experimental results on models without limiter give good coincidence with theoretical calculations. Spectra measured on impacting rod become smoother with increasing impacting level. Spectra of fuel rods have a wider range in impacting rate and higher level of smoothing than spectra of model rod have. The impacting rate strongly depends on mechanical properties of the rod. By the experiments, one can state that as for Fourier spectra the only thing caused by the impacts is the smoothening. However, there is a chance to give faulty diagnosis by Fourier spectra only. Consequently, investigation of fuel rod vibration requires increased caution. (author) 4 refs.; 12 figs.; 1 tab

  17. Nanosized Selenium: A Novel Platform Technology to Prevent Bacterial Infections

    Science.gov (United States)

    Wang, Qi

    As an important category of bacterial infections, healthcare-associated infections (HAIs) are considered an increasing threat to the safety and health of patients worldwide. HAIs lead to extended hospital stays, contribute to increased medical costs, and are a significant cause of morbidity and mortality. In the United States, infections encountered in the hospital or a health care facility affect more than 1.7 million patients, cost 35.7 billion to 45 billion, and contribute to 88,000 deaths in hospitals annually. The most conventional and widely accepted method to fight against bacterial infections is using antibiotics. However, because of the widespread and sometimes inappropriate use of antibiotics, many strains of bacteria have rapidly developed antibiotic resistance. Those new, stronger bacteria pose serious, worldwide threats to public health and welfare. In 2014, the World Health Organization (WHO) reported antibiotic resistance as a global serious threat that is no longer a prediction for the future but is now reality. It has the potential to affect anyone, of any age, in any country. The most effective strategy to prevent antibiotic resistance is minimizing the use of antibiotics. In recent years, nanomaterials have been investigated as one of the potential substitutes of antibiotics. As a result of their vastly increased ratio of surface area to volume, nanomaterials will likely exert a stronger interaction with bacteria which may affect bacterial growth and propagation. A major concern of most existing antibacterial nanomaterials, like silver nanoparticles, is their potential toxicity. But selenium is a non-metallic material and a required nutrition for the human body, which is recommended by the FDA at a 53 to 60 μg daily intake. Nanosized selenium is considered to be healthier and less toxic compared with many metal-based nanomaterials due to the generation of reactive oxygen species from metals, especially heavy metals. Therefore, the objectives of

  18. Automatic safety rod for reactors. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-03-23

    An automatic safety rod for a nuclear reactor containing neutron absorbing material and designed to be inserted into a reactor core after a loss-of-flow. Actuation is based upon either a sudden decrease in core pressure drop or the pressure drop decreases below a predetermined minimum value. The automatic control rod includes a pressure regulating device whereby a controlled decrease in operating pressure due to reduced coolant flow does not cause the rod to drop into the core.

  19. Temperature actuated automatic safety rod release

    Science.gov (United States)

    Hutter, E.; Pardini, J.A.; Walker, D.E.

    1984-03-13

    A temperature-actuated apparatus is disclosed for releasably supporting a safety rod in a nuclear reactor, comprising a safety rod upper adapter having a retention means, a drive shaft which houses the upper adapter, and a bimetallic means supported within the drive shaft and having at least one ledge which engages a retention means of the safety rod upper adapter. A pre-determined increase in temperature causes the bimetallic means to deform so that the ledge disengages from the retention means, whereby the bimetallic means releases the safety rod into the core of the reactor.

  20. Control rod selecting and driving device

    International Nuclear Information System (INIS)

    Isobe, Hideo.

    1981-01-01

    Purpose: To simultaneously drive a predetermined number of control rods in a predetermined mode by the control of addresses for predetermined number of control rods and read or write of driving codified data to and from the memory by way of a memory controller. Constitution: The system comprises a control rod information selection device for selecting predetermined control rods from a plurality of control rods disposed in a reactor and outputting information for driving them in a predetermined mode, a control rod information output device for codifying the information outputted from the above device and outputting the addresses to the predetermined control rods and driving mode coded data, and a driving device for driving said predetermined control rods in a predetermined mode in accordance with the codified data outputted from the above device, said control rod infromation output device comprising a memory device capable of storing a predetermined number of the codified data and a memory control device for storing the predetermined number of data into the above memory device at a predetermined timing while successively outputting the thus stored predetermined number of data at a predetermined timing. (Seki, T.)

  1. Nuclear fuel rod end plug weld inspection

    International Nuclear Information System (INIS)

    Parker, M. A.; Patrick, S. S.; Rice, G. F.

    1985-01-01

    Apparatus and method for testing TIG (tungsten inert gas) welds of end plugs on a sealed nuclear reactor fuel rod. An X-ray fluorescent spectrograph testing unit detects tungsten inclusion weld defects in the top end plug's seal weld. Separate ultrasonic weld inspection system testing units test the top end plug's seal and girth welds and test the bottom end plug's girth weld for penetration, porosity and wall thinning defects. The nuclear fuel rod is automatically moved into and out from each testing unit and is automatically transported between the testing units by rod handling devices. A controller supervises the operation of the testing units and the rod handling devices

  2. Growth and Morphology of Rod Eutectics

    Energy Technology Data Exchange (ETDEWEB)

    Jing Teng; Shan Liu; R. Trivedi

    2008-03-17

    The formation of rod eutectic microstructure is investigated systematically in a succinonitrile-camphor alloy of eutectic composition by using the directional solidification technique. A new rod eutectic configuration is observed in which the rods form with elliptical cylindrical shape. Two different orientations of the ellipse are observed that differ by a 90{sup o} rotation such that the major and the minor axes are interchanged. Critical experiments in thin samples, where a single layer of rods forms, show that the spacing and orientation of the elliptic rods are governed by the growth rate and the sample thickness. In thicker samples, multi layers of rods form with circular cross-section and the scaling law between the spacing and velocity predicted by the Jackson and Hunt model is validated. A theoretical model is developed for a two-dimensional array of elliptical rods that are arranged in a hexagonal or a square array, and the results are shown to be consistent with the experimental observations. The model of elliptic rods is also shown to reduce to that for the circular rod eutectic when the lengths of the two axes are equal, and to the lamellar eutectic model when one of the axes is much larger than the other one.

  3. Prototypical Rod Consolidation Demonstration Project

    International Nuclear Information System (INIS)

    1993-05-01

    The objective of Phase 3 of the Prototypical Rod consolidation Demonstration Project (PRCDP) was to procure, fabricate, assemble, and test the Prototypical Rod consolidation System as described in the NUS Phase 2 Final Design Report. This effort required providing the materials, components, and fabricated parts which makes up all of the system equipment. In addition, it included the assembly, installation, and setup of this equipment at the Cold Test Facility. During the Phase 3 effort the system was tested on a component, subsystem, and system level. This volume 1, discusses the PRCDP Phase 3 Test Program that was conducted by the HALLIBURTON NUS Environmental Corporation under contract AC07-86ID12651 with the United States Department of Energy. This document, Volume 1, Book 5 discusses the following topics: Lower Cutting System Test Results and Analysis Report; NFBC Loading System Test Results and Analysis Report; Robotic Bridge Transporter Test Results and Analysis Report; RM-10A Remotec Manipulator Test Results and Analysis Report; and Manipulator Transporter Test Results and Analysis Report

  4. Attracting electromagnet for control rod

    International Nuclear Information System (INIS)

    Kato, Kazuo; Sasaki, Kotaro.

    1989-01-01

    Non-magnetic material plates with inherent resistivity of greater than 20 μΩ-cm and thickness of less than 3 mm are used for the end plates of attracting electromagnets for closed type control rods. By using such control rod attracting electromagnets, the scram releasing time can be shortened than usual. Since the armature attracting side of the electromagnet has to be sealed by a non-magnetic plate, a bronze plate of about 5 mm thickness has been used so far. Accordingly, non-magnetic plate is inserted to the electromagnet attracting face to increase air source length for improving to shorten the scram releasing time. This method, however, worsens the attracting property on one hand to require a great magnetomotive force. For overcoming these drawbacks, in the present invention, the material for tightly closing end plates in an electromagnet is changed from bronze plate to non-magnetic stainless steel SUS 303 or non-magnetic Monel metal and, in addition, the plate thickness is reduced to less than 5 mm thereby maintaining the attracting property and shortening the scram releasing time. (K.M.)

  5. Dry rod consolidation technology development

    International Nuclear Information System (INIS)

    Rasmussen, T.L.; Schoonen, D.H.; Fisher, M.W.

    1986-01-01

    The Department of Energy's (DOE) Office of Civilian Radioactive Waste Management (OCRWM) is funding a Program to consolidate commercial spent fuel for testing in dry storage casks and to develop technology that will be fed into other OCRWM Programs, e.g., Prototypical Consolidation Demonstration Program. The Program is being conducted at the Idaho National Engineering Laboratory (INEL) by the Operating Contractor, EGandG Idaho, Inc. Hardware and software have been designed and fabricated for installation in a hot cell adjacent to the Test Area North (TAN) Hot Shop Facility. This equipment will be used to perform dry consolidation of commercial spent fuel from the Virginia Power (VP) Cooperative Agreement Spent Fuel Storage Cask (SPSC) Demonstration Program and assemblies that had previously been stored at the Engine Maintenance and Disassembly (EMAD) facility in Nevada. Consolidation will be accomplished by individual, horizontal rod pulling. A computerized semi-automatic control system with operator involvement will be utilized to conduct consolidation operations. Special features have been incorporated in the design to allow crud collection and measurement of rod pulling forces. During consolidation operations, data will be taken to characterize this technology. Still photo, video tape, and other documentation will be generated to make developed information available to interested parties. Cold checkout of the hardware and software will complete in September of 1986. Following installation in the hot cell, consolidation operations will begin in January 1987. Resulting consolidated fuel will be utilized in the VP Cooperative Agreement SFSC Program

  6. Antibacterial properties of artificial eyes containing nano-sized particle silver.

    Science.gov (United States)

    Yang, Jae Wook; Choi, Jae-won; Lee, Sul Gee; Kim, Dong Soo

    2011-03-01

    The long-term use of an artificial eyes can lead to complications. Persistent physical stimulation and foreign body contact cause secondary infections. Secondary infection is an important complication after the placement of a artificial eyes and may be difficult to control without removing the artificial eyes. Because of these complications, patients get difficulties to wear prosthesis. Furthermore artificial eyes can change the normal bacterial flora of the patient's conjunctiva. Such postoperative infections might be overcome by improving the antimicrobial properties of the prosthesis surface. The space in the mold previously occupied by wax was filled with polymethyl methacrylate (PMMA) resin containing silver at a concentration of 300-700 ppm (parts per million) and the prosthesis was then heat cured. Microorganisms were grown on the treated and control surfaces. We cultured for 24 hours, then counted the number of bacteria in resin compositions containing nano-sized silver particles and controls (Stomacher 400(®) POLY-BAG). The surface of the artificial eye containing silver grew significantly fewer Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli on in vitro bacterial cultures. The antimicrobial activity was 4.8-6.2 times stronger than for the controls. The numbers of bacteria decreased by 99.9% using the PMMA resin containing silver. The artificial eyes containing silver that were produced in this study have antibacterial activity, cause little eye discharge, and emit far-infrared rays and anions, all of which promote the ocular health of the person wearing the artificial eye.

  7. Wall pressure fluctuations in rod bundles

    International Nuclear Information System (INIS)

    Moeller, S.V.

    1990-01-01

    Microphones and hot wires were applied for the measurement of wall pressure fluctuations and velocity fluctuations in rod bundles with several aspect ratios. By means of auto and cross spectral density functions their interdependence was investigated. Results show that the pressure fluctuations in rod bundles are mainly associated with the phenomenon of quasi-periodic flow pulsations between subchannels. (author)

  8. Tipping Time of a Quantum Rod

    Science.gov (United States)

    Parrikar, Onkar

    2010-01-01

    The behaviour of a quantum rod, pivoted at its lower end on an impenetrable floor and restricted to moving in the vertical plane under the gravitational potential, is studied analytically under the approximation that the rod is initially localized to a "small-enough" neighbourhood around the point of classical unstable equilibrium. It is shown…

  9. Study of the rod style SFRFQ structure

    CERN Document Server

    Yan Xue Qing; Chen J

    2002-01-01

    There is a problem about upper limit of energy in the RFQ structure, although it is a wonderful low-energy-suited high current accelerating structure. After proposing an improved rod style SFRFQ structure without reversed field, the author studies its energy gain and transverse motion. The rod style SFRFQ structure is roughly compared with diaphragm SFRFQ structure

  10. Method of inspecting control rod drive mechanism

    International Nuclear Information System (INIS)

    Sato, Tomomi; Tatemichi, Shin-ichiro; Hasegawa, Hidenobu.

    1988-01-01

    Purpose: To conduct inspection for control rod drives and fuel handling operations in parallel without taking out the entire fuel, while maintaining the reactor in a subcritical state. Method: Control rod drives are inspected through the release of connection between control rods and control rod drives, detachment and dismantling of control rod drives, etc. In this case, structural materials having neutron absorbing power equal to or greater than the control rods are inserted into the gap after taking out fuels. Since the structural materials have neutron absorbing portion, subcriticality is maintained by the neutron absorbing effect. Accordingly, there is no requirement for taking out all of the fuels, thereby enabling to check the control rod drives and conduct handling for the fuels in parallel. As a result, the number of days required for the inspection can be shortened and it is possible to improve the working efficiency for the decomposition, inspection, etc. of the control rod drives and, thus, improve the operation efficiency of the nuclear power plant thereby attaining the predetermined purpose. (Kawakami, Y.)

  11. Control rod controlling device of nuclear reactor

    International Nuclear Information System (INIS)

    Arita, Setsuo; Okido, Fumiyasu.

    1997-01-01

    The present invention concerns a control rod drive mechanism for use in a BWR, which does not apply undesired effects on monitoring of neutron instrumentation systems. Control rods are operated using an induction electric motor equipped with an electromagnetic brake as a driving source. The induction electric motor and the electromagnetic brake are driven by ON/OFF control. Since a switching element for driving the induction electric motor and the electromagnetic brake can be kept ON or OFF during control rod operation, electromagnetic noises are not generated during the operation of the control rods. Accordingly, the neutron instrumentation systems do not undergoing effects of electromagnetic noises during operation of control rods, and the neutron instrumentation system can accurately be monitored. (N.H.)

  12. Nuclear reactor with scrammable part length rod

    International Nuclear Information System (INIS)

    Bevilacqua, F.

    1979-01-01

    A new part length rod is provided. It may be used to control xenon induced power oscillations but to contribute to shutdown reactivity when a rapid shutdown of the reactor is required. The part length rod consists of a control rod with three regions. The lower control region is a longer weaker active portion separated from an upper stronger shorter poison section by an intermediate section which is a relative non-absorber of neutrons. The combination of the longer weaker control section with the upper high worth poison section permits the part length rod of this to be scrammed into the core when a reactor shutdown is required but also permits the control rod to be used as a tool to control power distribution in both the axial and radial directions during normal operation

  13. Waste utilization for the controlled synthesis of nanosized hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Nayar, Suprabha, E-mail: Suprabha.nayar@gmail.com [National Metallurgical Laboratory, Jamshedpur (India); Guha, Avijit [National Metallurgical Laboratory, Jamshedpur (India)

    2009-05-05

    This work uses biomolecules in waste and medicinally important materials for the synthesis of hydroxyapatite nanoparticles. Orange and potato peel, eggshell, papaya leaf and calendula flower extracts have varied biomolecules, which exert a significant, control on the in situ synthesis of nanosized hydroxyapatite particles. The biomimetic synthesis of inorganic particles using known matrices is already well established, however, there are only a few reports using compound extracts. The synthesized nanocomposite has been characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy studies. Role of varied biomolecules in controlled inorganic synthesis may have tremendous technological impact.

  14. Ecotoxicological studies of micro- and nanosized barium titanate on aquatic photosynthetic microorganisms.

    Science.gov (United States)

    Polonini, Hudson C; Brandão, Humberto M; Raposo, Nádia R B; Mouton, Ludovic; Yéprémian, Claude; Couté, Alain; Brayner, Roberta

    2014-09-01

    The interaction between live organisms and micro- or nanosized materials has become a current focus in toxicology. As nanosized barium titanate has gained momentum lately in the medical field, the aims of the present work are: (i) to assess BT toxicity and its mechanisms on the aquatic environment, using two photosynthetic organisms (Anabaena flos-aquae, a colonial cyanobacteria, and Euglena gracilis, a flagellated euglenoid); (ii) to study and correlate the physicochemical properties of BT with its toxic profile; (iii) to compare the BT behavior (and Ba(2+) released ions) and the toxic profile in synthetic (Bold's Basal, BB, or Mineral Medium, MM) and natural culture media (Seine River Water, SRW); and (iv) to address whether size (micro, BT MP, or nano, BT NP) is an issue in BT particles toxicity. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic efficiency were evaluated. The main conclusions are: (i) BT have statistically significant toxic effects on E. gracilis growth and viability even in small concentrations (1μgmL(-1)), for both media and since the first 24 h; on the contrary of on A. flos-aquae, to whom the effects were noticeable only for the higher concentrations (after 96 h: ≥75 μg mL(-1) for BT NP and =100 μg mL(-1) for BT MP, in BB; and ≥75 μg mL(-1) for both materials in SRW), in spite of the viability being affected in all concentrations; (ii) the BT behaviors in synthetic and natural culture media were slightly different, being the toxic effects more pronounced when grown in SRW - in this case, a worse physiological state of the organisms in SRW can occur and account for the lower resistance, probably linked to a paucity of nutrients or even a synergistic effect with a contaminant from the river; and (iii) the effects seem to be mediated by induced stress without a direct contact in A. flos-aquae and by direct endocytosis in E. gracilis, but in

  15. Luminescence properties of YAG: Nd 3 nano-sized ceramic powders ...

    Indian Academy of Sciences (India)

    Nano-sized ceramic powders with weaker aggregation of Nd3+-doped yttrium aluminum garnet (YAG:Nd3+) were synthesized via co-microemulsion and microwave heating. This method provides a limited small space in a micelle for the formation of nano-sized precursors. It also requires a very short heating time, thus ...

  16. Application of Nanosize Zeolite Molecular Sieves for Medical Oxygen Concentration

    Directory of Open Access Journals (Sweden)

    Mingfei Pan

    2017-07-01

    Full Text Available The development of a portable oxygen concentrator is of prime significance for patients with respiratory problems. This paper presents a portable concentrator prototype design using the pressure/vacuum swing adsorption (PVSA cycle with a deep evacuation step (−0.82 barg instead of desorption with purge flow to simplify the oxygen production process. The output of the oxygen concentrator is a ~90 vol % enriched oxygen stream in a continuous adsorption and desorption cycle (cycle time ~90 s. The size of the adsorption column is 3 cm in diameter and 20 cm in length. A Li+ exchanged 13X nanosize zeolite is used as the adsorbent to selectively adsorb nitrogen from air. A dynamic model of the pressure and vacuum swing adsorption units was developed to study the pressurization and depressurization process inside the microporous area of nanosized zeolites. The describing equations were solved using COMSOL Multiphysics Chemical Engineering module. The output flow rate and oxygen concentration results from the simulation model were compared with the experimental data. Velocity and concentration profiles were obtained to study the adsorption process and optimize the operational parameters.

  17. Control Rod Malfunction at the NRAD Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Thomas L. Maddock

    2010-05-01

    The neutron Radiography Reactor (NRAD) is a training, research, and isotope (TRIGA) reactor located at the INL. The reactor is normally shut down by the insertion of three control rods that drop into the core when power is removed from electromagnets. During a routine shutdown, indicator lights on the console showed that one of the control rods was not inserted. It was initially thought that the indicator lights were in error because of a limit switch that was out of adjustment. Through further testing, it was determined that the control rod did not drop when the scram switch was initially pressed. The control rod anomaly led to a six month shutdown of the reactor and an in depth investigation of the reactor protective system. The investigation looked into: scram switch operation, console modifications, and control rod drive mechanisms. A number of latent issues were discovered and corrected during the investigation. The cause of the control rod malfunction was found to be a buildup of corrosion in the control rod drive mechanism. The investigation resulted in modifications to equipment, changes to both operation and maintenance procedures, and additional training. No reoccurrences of the problem have been observed since corrective actions were implemented.

  18. Nondestructive assay of HTGR fuel rods

    International Nuclear Information System (INIS)

    Menlove, H.O.

    1974-01-01

    Performance characteristics of three different radioactive source NDA systems are compared for the assay of HTGR fuel rods and stacks of rods. These systems include the fast neutron Sb-Be assay system, the 252 Cf ''Shuffler,'' and the thermal neutron PAPAS assay system. Studies have been made to determinethe perturbation on the measurements from particle size, kernel Th/U ratio, thorium content, and hydrogen content. In addition to the total 235 U determination, the pellet-to-pellet or rod-to-rod uniformity of HTGR fuel rod stacks has been measured by counting the delayed gamma rays with a NaI through-hole in the PAPAS system. These measurements showed that rod substitutions can be detected easily in a fuel stack, and that detailed information is available on the loading variations in a uniform stack. Using a 1.0 mg 252 Cf source, assay rates of 2 to 4 rods/s are possible, thus facilitating measurement of 100 percent of a plant's throughput. (U.S.)

  19. Estimation of irradiated control rod worth

    International Nuclear Information System (INIS)

    Varvayanni, M.; Catsaros, N.; Antonopoulos-Domis, M.

    2009-01-01

    When depleted control rods are planned to be used in new core configurations, their worth has to be accurately predicted in order to deduce key design and safety parameters such as the available shutdown margin. In this work a methodology is suggested for the derivation of the distributed absorbing capacity of a depleted rod, useful in the case that the level of detail that is known about the irradiation history of the control rod does not allow an accurate calculation of the absorber's burnup. The suggested methodology is based on measurements of the rod's worth carried out in the former core configuration and on corresponding calculations based on the original (before first irradiation) absorber concentration. The methodology is formulated for the general case of the multi-group theory; it is successfully tested for the one-group approximation, for a depleted control rod of the Greek Research Reactor, containing five neutron absorbers. The computations reproduce satisfactorily the irradiated rod worth measurements, practically eliminating the discrepancy of the total rod worth, compared to the computations based on the nominal absorber densities.

  20. Control rod housing alignment and repair apparatus

    International Nuclear Information System (INIS)

    Dixon, R.C.; Deaver, G.A.; Punches, J.R.; Singleton, G.E.; Erbes, J.G.; Offer, H.P.

    1991-01-01

    This patent describes a welding a repair device for precisely locating and welding the position of the top of a control rod drive housing attached from a stub tube from a corresponding aperture and alignment pin in a core plate within a boiling water nuclear reactor, the welding and repair device. It comprises: a shaft, the shaft extending from the vicinity of the top of the control rod drive housing up to and through the aperture in the core plate; means for registering to the aperture and the alignment pin on the core plate; a fixture attached to the bottom end of the shaft for mating to the top of the control rod drive housing in precise mating relationship; the fixture attached to the bottom end of the shaft whereby the fixture, when mated to the control rod drove housing and the registering means when registered to the alignment pin and aperture on the core plate imparts to the shaft, and angularity between the top of the control rod drive housing and the hole in the core plate; a hollow cylinder, the cylinder mounted for depending and sealed support with respect to the shaft above, about and below the control rod drive housing top; the cylinder depending down below the control rod drive housing to an elevation below the top of the sub tube; a rotating welding apparatus with a welding head for dispensing weldment mounted for rotation with respect to the shaft; the welding head disposed at the juncture between the side of the control rod drive housing and the stub tube; and means for flooding the cylinder with gas whereby the cylinder may be lowered. flooded in a gas environment and effect a weld between the top of the stub tube and the control rod drive housing

  1. Apparatus for handling control rod drives

    International Nuclear Information System (INIS)

    Akimoto, A.; Watanabe, M.; Yoshida, T.; Sugaya, Z.; Saito, T.; Ishii, Y.

    1979-01-01

    An apparatus for handling control rod drives (CRD's) attached by detachable fixing means to housings mounted in a reactor pressure vessel and each coupled to one of control rods inserted in the reactor pressure vessel is described. The apparatus for handling the CRD's comprise cylindrical housing means, uncoupling means mounted in the housing means for uncoupling each of the control rods from the respective CRD, means mounted on the housing means for effecting attaching and detaching of the fixing means, means for supporting the housing means, and means for moving the support means longitudinally of the CRD

  2. Control rod drive hydraulic device

    International Nuclear Information System (INIS)

    Takekawa, Toru.

    1994-01-01

    The device of the present invention can reliably prevent a possible erroneous withdrawal of control rod driving mechanism when the pressure of a coolant line is increased by isolation operation of hydraulic control units upon periodical inspection for a BWR type reactor. That is, a coolant line is connected to the downstream of a hydraulic supply device. The coolant line is connected to a hydraulic control unit. A coolant hydraulic detection device and a pressure setting device are disposed to the coolant line. A closing signal line and a returning signal line are disposed, which connect the hydraulic supply device and a flow rate control valve for the hydraulic setting device. In the device of the present invention, even if pressure of supplied coolants is elevated due to isolation of hydraulic control units, the elevation of the hydraulic pressure can be prevented. Accordingly, reliability upon periodical reactor inspection can be improved. Further, the facility is simplified and the installation to an existent facility is easy. (I.S.)

  3. Taylor impact of glass rods

    International Nuclear Information System (INIS)

    Willmott, G.R.; Radford, D.D.

    2005-01-01

    The deformation and fracture behavior of soda-lime and borosilicate glass rods was examined during classic and symmetric Taylor impact experiments for impact pressures to 4 and 10 GPa, respectively. High-speed photography and piezoresistive gauges were used to measure the failure front velocities in both glasses, and for impact pressures below ∼2 GPa the failure front velocity increases rapidly with increasing pressure. As the pressure was increased above ∼3 GPa, the failure front velocities asymptotically approached maximum values between the longitudinal and shear wave velocities of each material; at ∼4 GPa, the average failure front velocities were 4.7±0.5 and 4.6±0.5 mm μs -1 for the soda-lime and borosilicate specimens, respectively. The observed mechanism of failure in these experiments involved continuous pressure-dependent nucleation and growth of microcracks behind the incident wave. As the impact pressure was increased, there was a decrease in the time to failure. The density of cracks within the failed region was material dependent, with the more open-structured borosilicate glass showing a larger fracture density

  4. Dry rod consolidation technology development

    International Nuclear Information System (INIS)

    Rasmussen, T.L.; Schoonen, D.H.; Feldman, E.M.; Fisher, M.W.

    1987-01-01

    The Department of Energy's (DOE) Office of Civilian Radioactive Waste Management (OCRWM) is funding a program to consolidate commercial spent fuel for testing in dry storage casks and to develop technology that will be fed into other OCRWM programs, e.g., Prototypical Consolidation Demonstration Program (PCDP). The program is being conducted at the Idaho National Engineering Laboratory (INEL) by the INEL Operating Contractor EG and G Idaho, Inc. Hardware and software have been designed and fabricated for installation in a hot cell adjacent to the Test Area North (TAN) Hot Shop Facility. This equipment is used to perform dry consolidation of commercial spent fuel from the Virginia Power (VP) Cooperative Agreement Spent Fuel Storage Cask (SFSC) Demonstration Program and assemblies that had previously been stored at the Engine Maintenance and Disassembly (EMAD) facility in Nevada. Consolidation is accomplished by individual, horizontal rod pulling. A computerized semiautomatic control system with operator involvement is utilized to conduct consolidation operations. During consolidation operations, data is taken to characterize this technology. Still photo, video tape, and other documentation will be generated to make developed information available to interested parties. Cold checkout of the hardware and software was completed in September of 1986. Following installation in the hot cell, consolidation operations begins in May 1987. Resulting consolidated fuel will be utilized in the VP Cooperative Agreement SFSC Program

  5. Control rod for a nuclear reactor

    International Nuclear Information System (INIS)

    Roman, W.G.; Sutton, H.G. Jr.

    1979-01-01

    A control rod assembly for a nuclear reactor is disclosed having a remotely disengageable coupling between the control rod and the control rod drive shaft. The coupling is actuated by first lowering then raising the drive shaft. The described motion causes axial repositioning of a pin in a grooved rotatable cylinder, each being attached to different parts of the drive shaft which are axially movable relative to each other. In one embodiment, the relative axial motion of the parts of the drive shaft is used either to couple or to uncouple the connection by forcing resilient members attached to the drive shaft into or out of shouldered engagement, respectively, with an indentation formed in the control rod

  6. Control rod for a nuclear reactor

    International Nuclear Information System (INIS)

    Roman, W.G.; Sutton, H.G. Jr.

    1976-01-01

    A control rod assembly for a nuclear reactor is disclosed having a remotely disengageable coupling between the control rod and the control rod drive shaft. The coupling is actuated by first lowering then raising the drive shaft. The described motion causes axial repositioning of a pin in a grooved rotatable cylinder, each being attached to different parts of the drive shaft which are axially movable relative to each other. In one embodiment, the relative axial motion of the parts of the drive shaft is used either to couple or to uncouple the connection by forcing resilent members attached to the drive shaft into or out of shouldered engagement, respectively, with an indentation formed in the control rod

  7. Rod bundle burnout data and correlation comparisons

    International Nuclear Information System (INIS)

    Yoder, G.L.; Morris, D.G.; Mullins, C.B.

    1985-01-01

    Rod bundle burnout data from 30 steady-state and 3 transient tests were obtained from experiments performed in the Thermal Hydraulic Test Facility at the Oak Ridge National Laboratory. The tests covered a parameter range relevant to intact core reactor accidents ranging from large break to small break loss-ofcoolant conditions. Instrumentation within the 64-rod test section indicated that burnout occurred over an axial range within the bundle. The distance from the point where the first dry rod was detected to the point where all rods were dry was up to 60 cm in some of the tests. The burnout data should prove useful in developing new correlations for use in reactor thermalhydraulic codes. Evaluation of several existing critical heat flux correlations using the data show that three correlations, the Barnett, Bowring, and Katto correlations, perform similarly and correlate the data better than the Biasi correlation

  8. Genetics Home Reference: cone-rod dystrophy

    Science.gov (United States)

    ... common cause of autosomal recessive cone-rod dystrophy , accounting for 30 to 60 percent of cases. At ... Patient Support and Advocacy Resources (4 links) American Foundation for the Blind Foundation Fighting Blindness Retina International ...

  9. Control rod drive of nuclear reactor

    International Nuclear Information System (INIS)

    Zhuchkov, I.I.; Gorjunov, V.S.; Zaitsev, B.I.

    1980-01-01

    This invention relates to nuclear reactors and, more particularly, to a drive of a control rod of a nuclear reactor and allows power control, excess reactivity compensation, and emergency shut-down of a reactor. (author)

  10. Growth and characterizations of GaN micro-rods on graphene films for flexible light emitting diodes

    Directory of Open Access Journals (Sweden)

    Kunook Chung

    2014-09-01

    Full Text Available We report the growth of GaN micro-rods and coaxial quantum-well heterostructures on graphene films, together with structural and optical characterization, for applications in flexible optical devices. Graphene films were grown on Cu foil by means of chemical vapor deposition, and used as the substrates for the growth of the GaN micro-rods, which were subsequently transferred onto SiO2/Si substrates. Highly Si-doped, n-type GaN micro-rods were grown on the graphene films using metal–organic chemical vapor deposition. The growth and vertical alignment of the GaN micro-rods, which is a critical factor for the fabrication of high-performance light-emitting diodes (LEDs, were characterized using electron microscopy and X-ray diffraction. The GaN micro-rods exhibited promising photoluminescence characteristics for optoelectronic device applications, including room-temperature stimulated emission. To fabricate flexible LEDs, InxGa1–xN/GaN multiple quantum wells and a p-type GaN layer were deposited coaxially on the GaN micro-rods, and transferred onto Ag-coated polymer substrates using lift-off. Ti/Au and Ni/Au metal layers were formed to provide electrical contacts to the n-type and p-type GaN regions, respectively. The micro-rod LEDs exhibited intense emission of visible light, even after transfer onto the flexible polymer substrate, and reliable operation was achieved following numerous cycles of mechanical deformation.

  11. Control rod excess withdrawal prevention device

    International Nuclear Information System (INIS)

    Takayama, Yoshihito.

    1992-01-01

    Excess withdrawal of a control rod of a BWR type reactor is prevented. That is, the device comprises (1) a speed detector for detecting the driving speed of a control rod, (2) a judging circuit for outputting an abnormal signal if the driving speed is greater than a predetermined level and (3) a direction control valve compulsory closing circuit for controlling the driving direction of inserting and withdrawing a control rod based on an abnormal signal. With such a constitution, when the with drawing speed of a control rod is greater than a predetermined level, it is detected by the speed detector and the judging circuit. Then, all of the direction control valve are closed by way of the direction control valve compulsory closing circuit. As a result, the operation of the control rod is stopped compulsorily and the withdrawing speed of the control rod can be lowered to a speed corresponding to that upon gravitational withdrawal. Accordingly, excess withdrawal can be prevented. (I.S)

  12. Control rod for FBR type reactor

    International Nuclear Information System (INIS)

    Nakai, Koichi.

    1993-01-01

    In a control rod for an LMFBR type reactor, a thermal resistor is disposed between a temperature sensitive cylinder and a cam unit support rod. A thermal expansion difference due to the temperature difference is caused between the temperature sensitive cylinder and the cam unit support rod only upon abrupt temperature change of coolants. A control rod shaft extending mechanism of downwardly depressing an absorbent portion by amplifying the thermal expansion difference by an extension link mechanism and the cam unit is provided. The thermal resistor comprises inconel 625 or like other steel of small heat conductivity. If a certain abnormality should cause to the reactor system to elevate the coolant temperature in the reactor elevates abruptly and the reactor shutdown system does not actuate, since the control rod extension shaft extends to urge the absorbent and lower the reactor core reactivity, so that leading to serious accident can be prevented surely. Further, the control rod extension shaft does not extend upon moderate temperature elevation in the usual startup and causes no unnecessary reactivity change. (N.H.)

  13. Crippling Strength of Axially Loaded Rods

    Science.gov (United States)

    Natalis, FR

    1921-01-01

    A new empirical formula was developed that holds good for any length and any material of a rod, and agrees well with the results of extensive strength tests. To facilitate calculations, three tables are included, giving the crippling load for solid and hollow sectioned wooden rods of different thickness and length, as well as for steel tubes manufactured according to the standards of Army Air Services Inspection. Further, a graphical method of calculation of the breaking load is derived in which a single curve is employed for determination of the allowable fiber stress. Finally, the theory is discussed of the elastic curve for a rod subject to compression, according to which no deflection occurs, and the apparent contradiction of this conclusion by test results is attributed to the fact that the rods under test are not perfectly straight, or that the wall thickness and the material are not uniform. Under the assumption of an eccentric rod having a slight initial bend according to a sine curve, a simple formula for the deflection is derived, which shows a surprising agreement with test results. From this a further formula is derived for the determination of the allowable load on an eccentric rod. The resulting relations are made clearer by means of a graphical representation of the relation of the moments of the outer and inner forces to the deflection.

  14. Epigenomic landscapes of retinal rods and cones

    Science.gov (United States)

    Mo, Alisa; Luo, Chongyuan; Davis, Fred P; Mukamel, Eran A; Henry, Gilbert L; Nery, Joseph R; Urich, Mark A; Picard, Serge; Lister, Ryan; Eddy, Sean R; Beer, Michael A; Ecker, Joseph R; Nathans, Jeremy

    2016-01-01

    Rod and cone photoreceptors are highly similar in many respects but they have important functional and molecular differences. Here, we investigate genome-wide patterns of DNA methylation and chromatin accessibility in mouse rods and cones and correlate differences in these features with gene expression, histone marks, transcription factor binding, and DNA sequence motifs. Loss of NR2E3 in rods shifts their epigenomes to a more cone-like state. The data further reveal wide differences in DNA methylation between retinal photoreceptors and brain neurons. Surprisingly, we also find a substantial fraction of DNA hypo-methylated regions in adult rods that are not in active chromatin. Many of these regions exhibit hallmarks of regulatory regions that were active earlier in neuronal development, suggesting that these regions could remain undermethylated due to the highly compact chromatin in mature rods. This work defines the epigenomic landscapes of rods and cones, revealing features relevant to photoreceptor development and function. DOI: http://dx.doi.org/10.7554/eLife.11613.001 PMID:26949250

  15. International symposium on fuel rod simulators: development and application

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, R.W. (comp.)

    1981-05-01

    Separate abstracts are included for each of the papers presented concerning fuel rod simulator operation and performance; simulator design and evaluation; clad heated fuel rod simulators and fuel rod simulators for cladding investigations; fuel rod simulator components and inspection; and simulator analytical modeling. Ten papers have previously been input to the Energy Data Base.

  16. Method for compacting spent nuclear reactor fuel rods

    International Nuclear Information System (INIS)

    Wachter, W.J.

    1988-01-01

    In a nuclear reactor system which requires periodic physical manipulation of spent fuel rods, the method of compacting fuel rods from a fuel rod assembly is described. The method consists of: (1) removing the top end from the fuel rod assembly; (2) passing each of multiple fuel rod pulling elements in sequence through a fuel rod container and thence through respective consolidating passages in a fuel rod directing chamber; (3) engaging one of the pulling elements to the top end of each of the fuel rods; (4) drawing each of the pulling elements axially to draw the respective engaged fuel rods in one axial direction through the respective the passages in the chamber to thereby consolidate the fuel rods into a compacted configuration of a cross-sectional area smaller than the cross-sectional area occupied thereby within the fuel rod assembly; and (5) drawing all of the engaged fuel rods concurrently and substantially parallel to one another in the one axial direction into the fuel rod container while maintaining the compacted configuration whereby the fuel rods are aligned within the container in a fuel rod density of the the fuel rod assembly

  17. Nanosized f.c.c. thallium inclusions in aluminium

    International Nuclear Information System (INIS)

    Johnson, E.; Johansen, A.; Thoft, N.B.; Andersen, H.H.; Sarholt-Kristensen, L.

    1993-01-01

    Ion implantation of pure aluminium with thallium induces the formation of nanosized crystalline inclusions of thallium with a f.c.c. structure. The size of the inclusions depends on the implantation conditions and subsequent annealing treatments and is typically in the range from 1 to 10 nm. The inclusions are aligned topotactically with the aluminium matrix with a cube-cube orientation relationship and they have a truncated octahedral shape bounded by {111} and {001} planes. The lattice parameter of the f.c.c. thallium inclusions is 0.484 ± 0.002 nm, which is slightly but significantly larger than in the high-pressure f.c.c. thallium phase known to be stable above 3.8 GPa. (Author)

  18. Nanosized Minicells Generated by Lactic Acid Bacteria for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Huu Ngoc Nguyen

    2017-01-01

    Full Text Available Nanotechnology has the ability to target specific areas of the body, controlling the drug release and significantly increasing the bioavailability of active compounds. Organic and inorganic nanoparticles have been developed for drug delivery systems. Many delivery systems are through clinical stages for development and market. Minicell, a nanosized cell generated by bacteria, is a potential particle for drug delivery because of its size, safety, and biodegradability. Minicells produced by bacteria could drive therapeutic agents against cancer, microbial infection, and other diseases by targeting. In addition, minicells generated by lactic acid bacteria being probiotics are more interesting than others because of their benefits like safety, immunological improvement, and biodegradation. This review aims to highlight the stages of development of nanoparticle for drug delivery and discuss their advantages and limitations to clarify minicells as a new opportunity for the development of potential nanoparticle for drug delivery.

  19. Nuclear reactor remote disconnect control rod coupling indicator

    International Nuclear Information System (INIS)

    Vuckovich, M.

    1977-01-01

    A coupling indicator for use with nuclear reactor control rod assemblies which have remotely disengageable couplings between the control rod and the control rod drive shaft is described. The coupling indicator indicates whether the control rod and the control rod drive shaft are engaged or disengaged. A resistive network, utilizing magnetic reed switches, senses the position of the control rod drive mechanism lead screw and the control rod position indicating tube, and the relative position of these two elements with respect to each other is compared to determine whether the coupling is engaged or disengaged

  20. Graphic Grown Up

    Science.gov (United States)

    Kim, Ann

    2009-01-01

    It's no secret that children and YAs are clued in to graphic novels (GNs) and that comics-loving adults are positively giddy that this format is getting the recognition it deserves. Still, there is a whole swath of library card-carrying grown-up readers out there with no idea where to start. Splashy movies such as "300" and "Spider-Man" and their…

  1. Calculation of the local electric field for an infinite array of conducting nanosized objects

    International Nuclear Information System (INIS)

    Lim, Mikyoung; Kim, Dohyung; Kim, Sang Youl; Bouree, Jean-Eric

    2007-01-01

    The electric field for an infinite array of conducting nanosized objects in two-dimensional space has been calculated. The mirror symmetry for this physical problem has been introduced. By taking into account this symmetry, we transform the original problem into an infinite two-dimensional array of nanosized objects with the same solution. The electric field equation of the model has been successfully constructed using a single-layer potential of the periodic Green function. The electric field operator has been introduced. This mathematical approach yields a solution for determining the optimum structure of nanosized electronic devices such as carbon nanotube-based field emitters

  2. The enhanced photoactivity of nanosized Bi2WO6 catalyst for the degradation of 4-chlorophenol

    International Nuclear Information System (INIS)

    Fu Hongbo; Yao Wenqing; Zhang Liwu; Zhu Yongfa

    2008-01-01

    Nanosized Bi 2 WO 6 catalyst exhibited the enhanced photoactivity for the degradation of 4-chlorophenol (4-CP) under visible irradiation compared to the sample prepared by high-temperature solid reaction. The photoactivity of the catalyst was sensitive to pH variation of the suspension. Nanosized Bi 2 WO 6 catalyst showed the highest activity at pH 7.2. The photodegradation of 4-CP by nanosized Bi 2 WO 6 catalyst followed a pseudo-first-order reaction. After three recycling runs for the photodegradation of 4-CP, the activity of the catalyst did not show any significant loss, suggesting that the catalyst was stable under visible irradiation

  3. Evaluation of the ability of electrical rods to simulate nuclear rod behavior during a loss-of-coolant accident

    International Nuclear Information System (INIS)

    Tolman, E.L.; Gottula, R.C.

    1979-01-01

    The purpose of this report is twofold: (1) to assess the adequacy of electrical rods to simulate nuclear rod behavior during loss-of-coolant-accident (LOCA) conditions, and (2) to identify ongoing tests specifically designed to directly compare electric and nuclear rod response during a LOCA. The capability and limitations of electric rods to simulate LOCA fuel rod response are reviewed. Two tests, the Halden IFA-511 test and the German PNS 4237 test, are being conducted to directly compare electric rod and nuclear rod response under LOCA conditions. The objectives and usefulness of these tests are reviewed

  4. Determination of safety rod reactivity - time function from digitally measured safety rod trajectory

    International Nuclear Information System (INIS)

    Pesic, M.; Milovanovic, S.; Milovanovic, T.

    1996-01-01

    Using rod position - time function z(t), obtained using new method and reactivity - position function rho(z), the complex dependence of the reactivity - time function rho(t) for HERBE safety rods is determined. Some improvements, comparing to the previously proposed method, are obtained and analyzed. (author)

  5. In-Situ Growth and Characterization of Indium Tin Oxide Nanocrystal Rods

    Directory of Open Access Journals (Sweden)

    Yan Shen

    2017-11-01

    Full Text Available Indium tin oxide (ITO nanocrystal rods were synthesized in-situ by a vapor-liquid-solid (VLS method and electron beam evaporation technique. When the electron-beam gun bombarded indium oxide (In2O3 and tin oxide (SnO2 mixed sources, indium and tin droplets appeared and acted as catalysts. The nanocrystal rods were in-situ grown on the basis of the metal catalyst point. The nanorods have a single crystal structure. Its structure was confirmed by X-ray diffraction (XRD and transmission electron microscopy (TEM. The surface morphology was analyzed by scanning electron microscopy (SEM. During the evaporation, a chemical process was happened and an In2O3 and SnO2 solid solution was formed. The percentage of doped tin oxide was calculated by Vegard’s law to be 3.18%, which was in agreement with the mixture ratio of the experimental data. The single crystal rod had good semiconductor switch property and its threshold voltage of single rod was approximately 2.5 V which can be used as a micro switch device. The transmission rate of crystalline nanorods ITO film was over 90% in visible band and it was up to 95% in the blue green band as a result of the oxygen vacancy recombination luminescence.

  6. RODDRP - A FORTRAN program for use in control rod calibration by the rod drop method

    International Nuclear Information System (INIS)

    Wilson, W.E.

    1972-01-01

    The different methods to measure reactivity which are applicable to control rod calibration are discussed. They include: 1) the positive period method, 2) the rod drop method, 3) the source-jerk method, 4) the rod oscillation method, and 5) the pulsed neutron method. The instrument setup used at WSU for rod drop measurements is presented. To speed up the analysis of power fall-off trace, a FORTRAN IV program called RODDRP was written to simultaneously solve the in-hour equation and relative neutron flux. The procedure for calculating the worth of the rod that produced the power trace is given. The reactivity for each time relative flux point is obtained. Conclusions about the status of the equipment are made

  7. Bent Telescopic Rods in Patients With Osteogenesis Imperfecta.

    Science.gov (United States)

    Lee, R Jay; Paloski, Michael D; Sponseller, Paul D; Leet, Arabella I

    2016-09-01

    Telescopic rods require alignment of 2 rods to enable lengthening. A telescopic rod converts functionally into a solid rod if either rod bends, preventing proper engagement. Our goal was to characterize implant bending as a mode of failure of telescopic rods used in the treatment of osteogenesis imperfecta in children. We conducted a retrospective review of our osteogenesis imperfecta database for patients treated with intramedullary telescopic rods at our institution from 1992 through 2010 and identified 12 patients with bent rods. The 6 boys and 6 girls had an average age at the time of initial surgery of 3.1 years (range, 1.8 to 8.3 y) and a total of 51 telescoping rods. Clinic notes, operative reports, and radiographs were reviewed. The rods were analyzed for amount of lengthening, characteristics of bending, presence of cut out, or disengagement from an anchor point. Bends in the rods were characterized by their location on the implant component. The bent and straight rods were compared. Data were analyzed with the Mann-Whitney test (statistical significance set at P≤0.05). Of the 51 telescoping rods, 17 constructs (33%) bent. The average interval between surgery and rod bending was 4.0 years (range, 0.9 to 8.2 y). Before bending, 11 of 17 telescoping rods had routine follow-up radiographs for review. In 10 of the rods, bending was present when early signs of rod failure were first detected. Rod bending did not seem to be related to rod size. There was no area on the rod itself that seemed more susceptible to bending. Rod bending can be an early sign of impending rod failure. When rod bending is first noted, it may predispose the rod to other subsequent failures such as loss of proximal and distal fixation and cut out. Rod bending should be viewed as an indicator for closer monitoring of the patient and discussions regarding future need for rod exchange. Level III-retrospective review.

  8. Color dissociation artifacts in double Maddox rod cyclodeviation testing.

    Science.gov (United States)

    Simons, K; Arnoldi, K; Brown, M H

    1994-12-01

    The double Maddox rod test, based on a red Maddox rod in front of one eye and a clear Maddox rod in front of the other, is used to measure cyclodeviation, typically in patients with superior oblique muscle pareses. Discrepant results between the double Maddox rod test and other torsion measures, and reports of "paradoxic" cyclodeviation in the normal eye of some patients with superior oblique paresis, suggest the two-color format of the double Maddox rod test may produce artifactual torsion measures. Forty patients with superior oblique paresis were tested twice using the double Maddox rod test, reversing the red and white Maddox rods between eyes for the second test, and 18 were tested further with same-color red or clear Maddox rods in front of both eyes. With the standard double Maddox rod test, 33 (83%) of 40 patients localized their cyclodeviation to the eye viewing through the red Maddox rod, irrespective of laterality of the paresis or fixation preference. In all 33 patients, laterality of the perceived torsion changed between eyes when testing was repeated with red and white Maddox rods interchanged between eyes. With same-color Maddox rods before both eyes, 17 (94%) of 18 patients localized extorsion to the paretic eye. There was 7.6:1 ratio of luminance transmission and a 1.6:1 ratio of grating spatial frequency bandpass in the plano meridian between the clear and red Maddox rods, which appear to be responsible for the double Maddox rod test artifact. The traditional double Maddox rod test may produce artifactual cyclodeviation measurements. An alternative version of the test, based on same-color Maddox rods in front of both eyes, is proposed. The relatively high spatial frequency bandpass characteristics of the plano meridian of the Maddox rod (as high as 20/25 Snellen equivalent resolution through the clear Maddox rod) also suggests double Maddox rod testing should be conducted in a dark room to avoid biases from visual environment cues.

  9. Control rod driving hydraulic pressure device

    International Nuclear Information System (INIS)

    Ishida, Kazuo.

    1990-01-01

    Discharged water after actuating control rod drives in a BWR type reactor is once discharged to a discharging header, then returned to a master control unit and, subsequently, discharged to a reactor by way of a cooling water header. The radioactive level in the discharging header and the master control unit is increased by the reactor water to increase the operator's exposure. In view of the above, a riser is disposed for connecting a hydraulic pressure control unit incorporating a directional control valve and the cooling water head. When a certain control rod is inserted, the pressurized driving water is supplied through a hydraulic pressure control unit to the control rod drives. The discharged water from the control rod drives is entered by way of the hydraulic pressure control unit into the cooling water header and then returned to the reactor by way of other hydraulic pressure control unit and the control rod drives. Thus, the reactor water is no more recycled to the master control unit to reduce the radioactive exposure. (N.H.)

  10. Broadband Vibration Attenuation Using Hybrid Periodic Rods

    Directory of Open Access Journals (Sweden)

    S. Asiri

    2008-12-01

    Full Text Available This paper presents both theoretically and experimentally a new kind of a broadband vibration isolator. It is a table-like system formed by four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a system, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the "Pass Bands" and wave propagation is efficiently attenuated within other frequency bands called the "Stop Bands". The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. This concept can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

  11. Size-dependent superconducting state of individual nanosized Pb islands grown on Si(111) by tunneling spectroscopy.

    Science.gov (United States)

    Liu, Jiepeng; Wu, Xuefeng; Ming, Fangfei; Zhang, Xieqiu; Wang, Kedong; Wang, Bing; Xiao, Xudong

    2011-07-06

    By measuring the temperature-dependent tunneling spectroscopy of a set of flat-top Pb islands from 3.2 to 15 K, the limiting size of a nine-monolayer-thick Pb island with superconductivity above 3.2 K was determined to be ∼ 30 nm(2), in good agreement with the Anderson criterion. Further analysis indicates that the zero-temperature energy gap decreases significantly faster than the transition temperature when the Pb island size approaches this limit. This leads to a decrease of 2Δ(0)/k(B)T(C) from 4.5 to 3.3, thus showing that the Pb island superconductors undergo a change from strong to weak electron-phonon coupling. © 2011 IOP Publishing Ltd

  12. Rod consolidation at the West Valley Demonstration Project

    International Nuclear Information System (INIS)

    Bailey, W.J.

    1986-12-01

    A rod consolidation demonstration with irradiated pressurized water reactor fuel was recently conducted by personnel from Nuclear Assurance Corporation and West Valley Nuclear Services Company at the West Valley Demonstration Project in West Valley, New York. The rod consolidation demonstration involved pulling all of the fuel rods from six fuel Assemblies. In general, the rod pulling proceeded smoothly. The highest compaction ratio attained was 1:8:1. Among the total of 1074 fuel rods were some known degraded rods (they had collapsed cladding, a result of in-reactor fuel densification), but no rods were broken or dropped during the demonstration. One aim was to gather information on the effect of rod consolidation operations on the integrity of the fuel rods during subsequent handling and storage. Another goal was to collect information on the condition and handling of intact, damaged, and failed fuel that has been in storage for an extended period. 9 refs., 8 figs., 1 tab

  13. Mn 3 O 4 nano-sized crystals: Rapid synthesis and extension to ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 3. Mn3O4 nano-sized crystals: Rapid synthesis and extension to preparation of nanosized LiMn2O4 materials. Xiao-Ling Cui Yong-Li Li Shi-You Li Guo-Cun Sun Jin-Xia Ma Lu Zhang Tian-Ming Li Rong-Bo Ma. Regular Articles Volume 126 Issue 3 May ...

  14. Magnetic switch for reactor control rod. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-09-30

    A magnetic reed switch assembly is described for activating an electromagnetic grapple utilized to hold a control rod in position above a reactor core. In normal operation the magnetic field of a permanent magnet is short-circuited by a magnetic shunt, diverting the magnetic field away from the reed switch. The magnetic shunt is made of a material having a Curie-point at the desired release temperature. Above that temperature the material loses its ferromagnetic properties, and the magnetic path is diverted to the reed switch which closes and short-circuits the control circuit for the control rod electro-magnetic grapple which allows the control rod to drop into the reactor core for controlling the reactivity of the core.

  15. Method of diagnosing the control rod operation

    International Nuclear Information System (INIS)

    Nakaniwa, Tomoko; Kudo, Mitsuru.

    1983-01-01

    Purpose: To confirm the soundness of a control rod operation at high accuracy. Method: By utilizing the fact that a control rod position indicating system outputs digitalized decimal signals, position signals are outputted as below: a stop position signal when a magnet is opposed to an odd number limit switch; a drift position signal when it is opposed to an even number limit switch; and a blank position signal when it is not opposed to a limit switch. Since the standard signal pattern is present for the order of signal change due to the displacement of the magnet i.e., stop position→blank position→drift position, absolute position change and the time for passing the limit switch, the standard pattern is stored in an operation diagnosis unit and compared with the data upon actual driving to diagnose the control rod operation collectively. (Sekiya, K.)

  16. Performance analysis of LMFBR control rods

    International Nuclear Information System (INIS)

    Pitner, A.L.; Birney, K.R.

    1975-01-01

    Control rods in the FFTF and LMFBR's will consist of pin bundles of stainless steel-clad boron carbide pellets. In the FFTF reference design, sixty-one pins of 0.474-inch diameter each containing a 36-inch stack of 0.362-inch diameter boron carbide pellets comprise a control rod. Reactivity control is provided by the 10 B (n,α) 7 Li reaction in the boron carbide. This reaction is accompanied by an energy release of 2.8 MeV, and heating from this reaction typically approaches 100 watts/cm 3 for natural boron carbide pellets in an LMFBR flux. Performance analysis of LMFBR control rods must include an assessment of the thermal performance of control pins. In addition, irradiation performance with regard to helium release, pellet swelling, and reactivity worth depletion as a function of service time must be evaluated

  17. Elliptical cross section fuel rod study II

    International Nuclear Information System (INIS)

    Taboada, H.; Marajofsky, A.

    1996-01-01

    In this paper it is continued the behavior analysis and comparison between cylindrical fuel rods of circular and elliptical cross sections. Taking into account the accepted models in the literature, the fission gas swelling and release were studied. An analytical comparison between both kinds of rod reveals a sensible gas release reduction in the elliptical case, a 50% swelling reduction due to intragranular bubble coalescence mechanism and an important swelling increase due to migration bubble mechanism. From the safety operation point of view, for the same linear power, an elliptical cross section rod is favored by lower central temperatures, lower gas release rates, greater gas store in ceramic matrix and lower stored energy rates. (author). 6 refs., 8 figs., 1 tab

  18. Storing device for control rod drive

    International Nuclear Information System (INIS)

    Tomatsu, Tsutomu; Miura, Teruo.

    1989-01-01

    A water supply device for supplying clean water, a recycling pump and a filter disposed between the water supply device and a water vessel by way of recycling pipelines are disposed to a water vessel containing storing water for immerging and storing control rod drives for BWR type reactors upon periodical inspection, etc. Clean water is supplied from the water supply device into the control rod drives immerged in the storing water to remove radioactive cruds, etc. deposited at the surface thereof and water is supplied through the recycling pipelines to the filter to remove solid impurities contained therein and the clean water is returned to the water supply device. Since the clean water is always recycled to the inside of the control rod drives, chemical corrosion and electrical corrosion of nitride parts are prevented and radioactive cruds are processed in separated waste processing systems, the atmospheric radiation doses in the operation chamber is reduced. (S.K.)

  19. Method and apparatus for compacting spent nuclear reactor fuel rods

    International Nuclear Information System (INIS)

    Wachter, W.J.

    1988-01-01

    In a nuclear reactor system requiring periodic physical manipulation of spent fuel rods, the method of compacting fuel rods from a fuel rod assembly is described comprising the steps of: (1) removing the top end from pulling members having electrodes of weld elements in leading ends thereof in sequence through a fuel rod container and thence through respective consolidating passages in a fuel-rod directing chamber; (3) welding the weld elements of the pulling members to the top end of respective fuel rods corresponding to the respective pulling members; (4) drawing each of the pulling members axially to draw the respective engaged fuel rods in one axial direction through the respective passages in the chamber to thereby consolidate the fuel rods into a compacted configuration of a cross-sectional area smaller than the cross-sectional area occupied thereby within the fuel rod assembly; and (5) drawing all of the engaged fuel rods concurrently and substantially parallel to one another to the one axial direction into the fuel rod container while maintaining the compacting configuration in a fuel rod density which is greater than that of the fuel rod density of the fuel rod assembly

  20. HIGH STRENGTH CONTROL RODS FOR NEUTRONIC REACTORS

    Science.gov (United States)

    Lustman, B.; Losco, E.F.; Cohen, I.

    1961-07-11

    Nuclear reactor control rods comprised of highly compressed and sintered finely divided metal alloy panticles and fine metal oxide panticles substantially uniformly distributed theretbrough are described. The metal alloy consists essentially of silver, indium, cadmium, tin, and aluminum, the amount of each being present in centain percentages by weight. The oxide particles are metal oxides of the metal alloy composition, the amount of oxygen being present in certain percentages by weight and all the oxygen present being substantially in the form of metal oxide. This control rod is characterized by its high strength and resistance to creep at elevated temperatures.

  1. Oligo(naphthylene–ethynylene) Molecular Rods

    DEFF Research Database (Denmark)

    Cramer, Jacob Roland; Ning, Yanxiao; Shen, Cai

    2013-01-01

    of palladium-catalyzed Sonogashira reactions between naphthyl halides and acetylenes. The triazene functionality was used as a protected iodine precursor to allow linear extension of the molecular rods during the synthe-ses. The carboxylic acid groups in the target molecules were protected as esters during......Molecular rods designed for surface chirality studies have been synthesized in high yields. The molecules are composed of oligo(naphthylene–ethynylene) skeletons and functionalized at their two termini with carboxylic acids and hydrophobic groups. The molecular skeletons were constructed by means...

  2. Method for producing titanium aluminide weld rod

    Science.gov (United States)

    Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.

    1995-01-01

    A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

  3. Digital, electromagnetic rod position indicator with compensation

    International Nuclear Information System (INIS)

    Feilchenfeld, M.M.; Geis, C.G.

    1985-01-01

    A digital rod position indicator having discrete coils L 0 , L 1 , L 2 ..... spaced along the travel path of an elongate magnetically permeable member stores in digital form compensation signals for automatically adjusting the location relative to the coils at which a digital output signal representative of the position of the end of the elongate member transitions from one code to the next. The appropriate compensation signal is addressed using the digital output signal and a correction factor which takes into account the direction of movement including reversals. Reference is made to the positioning of the control rods in a pressurized water reactor. (author)

  4. Quivers For Special Fuel Rods-Disposal Of Special Fuel Rods In CASTOR V Casks

    International Nuclear Information System (INIS)

    Bannani, Amin; Cebula, Wojciech; Buchmuller, Olga; Huggenberg, Roland; Helmut Kuhl

    2015-01-01

    While GNS casks of the CASTOR family are a suitable means to transfer fuel assemblies (FA) from the NPP to an interim dry storage site, Germanys phase-out of nuclear energy has triggered the demand for an additional solution to dispose of special fuel rods (SFR), normally remaining in the fuel pond until the final shutdown of the NPP. SFR are fuel rods that had to be removed from fuel assemblies mainly due to their special condition, e. g. damages in the cladding of the fuel rods which may have occurred during reactor operations. SFR are usually stored in the spent fuel pond after they are removed from the FA. The quiver for special fuel rods features a robust yet simple design, with a high mechanical stability, a reliable leak-tightness and large safety margins for future requirements on safety analysis. The quiver for special fuel rods can be easily adapted to a large variety of different damaged fuel rods and tailored to the specific need of the customer. The quiver for special fuel rods is adaptable e.g. in length and diameter for use in other types of transport and storage casks and is applicable in other countries as well. The overall concept presented here is a first of its kind solution for the disposal of SFRs via Castor V-casks. This provides an important precondition in achieving the status 'free from nuclear fuel' of the shut down German NPPs

  5. Rod pomnožných proprií, rod v plurálu, rod obecně

    Czech Academy of Sciences Publication Activity Database

    Šimandl, Josef

    2012-01-01

    Roč. 49, 3/4 (2012), s. 124-128 ISSN 1212-5326. [Rod v jazyce a v jazykovědě. Praha, 08.12.2011] Institutional research plan: CEZ:AV0Z90610518 Keywords : gender of nouns * evidence of gender in plural Subject RIV: AI - Linguistics

  6. Infrared absorption spectra of nanosized silica with organic additives

    Directory of Open Access Journals (Sweden)

    Мaria О. Savchenko

    2014-12-01

    Full Text Available The prospects of using of silica nanoparticles modified with urea-formaldehyde polymers which is obtained by sulfuric acid sol-gel technology are shown. The aim is a detailed research on the infrared absorption spectra of nanodispersed silica modified with urea-formaldehyde polymers with identification of the absorption bands of the spectrum. The method of infrared spectroscopy is used to research spectral characteristics of nanosized silica, urea-formaldehyde polymer and nanodispersed silica modified with urea-formaldehyde polymers in different ratio. It is found that interaction of initial ingredients occurs at the stage of phase formation in solutions in colloidal silica products containing urea-formaldehyde polymers. Organic components are localized on the surface of the globules and in the interglobular space. This result of such interaction is the physical and structural transformation of globular surfaces of silica and new chemical compounds formation. This allows to give to final product a variety of properties required for practical use in many industries.

  7. Nanosized Building Blocks for Customizing Novel Antibiofilm Approaches.

    Science.gov (United States)

    Paula, A J; Koo, H

    2017-02-01

    Recent advances in nanotechnology provide unparalleled flexibility to control the composition, size, shape, surface chemistry, and functionality of materials. Currently available engineering approaches allow precise synthesis of nanocompounds (e.g., nanoparticles, nanostructures, nanocrystals) with both top-down and bottom-up design principles at the submicron level. In this context, these "nanoelements" (NEs) or "nanosized building blocks" can 1) generate new nanocomposites with antibiofilm properties or 2) be used to coat existing surfaces (e.g., teeth) and exogenously introduced surfaces (e.g., restorative or implant materials) for prevention of bacterial adhesion and biofilm formation. Furthermore, functionalized NEs 3) can be conceived as nanoparticles to carry and selectively release antimicrobial agents after attachment or within oral biofilms, resulting in their disruption. The latter mechanism includes "smart release" of agents when triggered by pathogenic microenvironments (e.g., acidic pH or low oxygen levels) for localized and controlled drug delivery to simultaneously kill bacteria and dismantle the biofilm matrix. Here we discuss inorganic, metallic, polymeric, and carbon-based NEs for their outstanding chemical flexibility, stability, and antibiofilm properties manifested when converted into bioactive materials, assembled on-site or delivered at biofilm-surface interfaces. Details are provided on the emerging concept of the rational design of NEs and recent technological breakthroughs for the development of a new generation of nanocoatings or functional nanoparticles for biofilm control in the oral cavity.

  8. Aloe vera Induced Biomimetic Assemblage of Nucleobase into Nanosized Particles

    Science.gov (United States)

    Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

    2012-01-01

    Aim Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. Methodology The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Results Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. Conclusion In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints. PMID:22403622

  9. Synthesis and Characterization of Nanosized Fe2O3 Pigments

    Directory of Open Access Journals (Sweden)

    M. F. R. Fouda

    2012-01-01

    Full Text Available The work in this paper was devoted to investigating some nanosized iron oxide pigments prepared by microemulsion technique. The role of concentration of iron salt and surfactant (cetyltrimethylammonium bromide on the produced iron oxide was studied. The techniques employed to characterize the samples were thermogravimetric analysis, X-ray diffractometry, transmission electron microscope, infrared spectroscopy, and diffuse reflectance spectroscopy. The results revealed that the particle size of the prepared sample using 0.2 M iron sulfate and 3.2 wt% of surfactant was in the range 7–9 nm. Increasing the concentration of either iron salt or the surfactant increased the particle size of the obtained ferric oxide. The diffuse reflectance measurements showed that the charge transfer/electron pair transition absorption peak, which is closely related to the reddish color of the oxide, was shifted to a longer wavelength (blue shift by decreasing the dimension of the particles. The samples were tested as pigments. They showed different tints of red color and were found to be promising for applications as pigments in the field of paint manufacturing.

  10. Aloe vera induced biomimetic assemblage of nucleobase into nanosized particles.

    Science.gov (United States)

    Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

    2012-01-01

    Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints.

  11. The Synthesis and Modification of Nanosized Clickable Latex Particles

    KAUST Repository

    Almahdali, Sarah

    2013-05-01

    This research aims to add to the current knowledge available for miniemulsion polymerization reactions and to use this knowledge to synthesize multifunctional nanosized latex particles that have the potential to be used in catalysis. The physical properties of the latex can be adjusted to suit various environments due to the multiple functional groups present. For this research, styrene, pentafluorostyrene, azidomethyl styrene, pentafluorostyrene with azidomethyl styrene and pentafluorostyrene with styrene latexes were produced, and analyzed by dynamic light scattering. The latexes were synthesized using a miniemulsion polymerization technique found through this research. Potassium oleate and potassium 1,1,2,2,3,3,4,4-nonafluorobutane-1-sulfonate were used as surfactants during the miniemulsion polymerization reaction to synthesize pentafluorostyrene with azidomethyl styrene latex. Transmission electron microscopy data and dynamic light scattering data have been collected to analyze the structure of this latex, and it has been synthesized using a number of conditions, differing in reaction time, surfactant amount and sonication methods. We have also improved the solubility of the latex through a copper(I) catalyzed 1,3-dipolar azide-alkyne reaction, by clicking (polyethylene glycol)5000 onto the azide functional groups.

  12. Superfocusing the light through the nanosize slit via photonic tornado

    Science.gov (United States)

    Choi, Seong Soo; Jha, Vinaya; Suwal, Om; Park, Myoung Jin; Park, Nam Kyu; Kim, Daisik

    2010-03-01

    The macro size pyramidal horn probe such as klystron horn antenna has been used to provide the excellent focusing capabilities in microwave region. In the similar way, the pyramidal probe with the micron size mirror (pyramidal horn probe) has been fabricated with a nano-size aperture with diameter ranging from ˜1 nm to ˜30 nm. Light transmission through the micro-fabricated pyramidal horn probe has been measured to enhance the light transmission due to resonant effects between the cavity mode and the slit modes in the probe, along with improved directionality of the transmitted beam. The resonant tunneling between two standing waves in the input groove and in the output groove can provide the transmission enhancements. With decreasing slit width, the transmission is found to increasing tremendously.[1] The transmission is measured to be inversely proportional to the area.[2,3] References:[1] R. Gordon, Phys. Rev. B 73, 153405 (2006).[2] R. Harrington, IEEE Trans. Antennas Propagat. Ap-30, 205(1982).[3] Y Leviatan, R. Harrington, J. Maut, IEEE Trans. Antennas Propagat. Ap-30, 1533(1982)

  13. Tribological properties of nanosized calcium carbonate filled polyamide 66 nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Itagaki, Kaito [Department of Mechanical Engineering, Graduate School of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015 Japan (Japan); Nishitani, Yosuke [Department of Mechanical Engineering, Faculty of Engineering, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo, 192-0015 Japan (Japan); Kitano, Takeshi [Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, T.G.M. 275, Zlin, 767 72 Czech Republic (Czech Republic); Eguchi, Kenichiro [Shiraishi Central Laboratories, 4-78 Motohama,Amagasaki,Hyogo,660-0085 Japan (Japan)

    2016-03-09

    For the purpose of developing high performance tribomaterials for mechanical sliding parts such as gears, bearings and so on, nanosized calcium carbonate (nano-CaCO{sub 3}) filled polyamide 66 (PA66) nanocomposites were investigated. The nano-CaCO{sub 3} was a kind of precipitated (colloid typed) CaCO{sub 3}, and its average particle size was 40, 80 and 150 nm. Surface treatment was performed by fatty acid on the nano-CaCO{sub 3} and its volume fraction in the nanocomposite was varied from 1 to 20vol.%. These nanocomposites were melt-mixed by a twin screw extruder and injection-molded. Tribological properties were measured by two types of sliding wear testers such as ring-on-plate type and ball-on-plate type one under dry condition. The counterface, worn surface and wear debris were observed by digital microscope and scanning electron microscope. It was found that the nano-CaCO{sub 3} has a good effect on the tribological properties, although the effect on the frictional coefficient and specific wear rate is differed by the volume fraction and the type of sliding wear modes. This is attributed to the change of wear mechanisms, which is the change of form of the transfer films on the counterface and the size of wear debris. It follows from these results that PA66/nano-CaCO{sub 3} nanocomposites may be possible to be the high performance tribomaterials.

  14. Strong enhancement of superconductivity in a nanosized Pb bridge

    Science.gov (United States)

    Misko, V. R.; Fomin, V. M.; Devreese, J. T.

    2001-07-01

    In recent experiments with a superconducting nanosized Pb bridge formed between a scanning tunneling microscope tip and a substrate, superconductivity has been detected at magnetic fields, that are a few times larger than the third (surface) critical field. We describe the observed phenomenon on the basis of a numerical solution of the Ginzburg-Landau equations in a model structure consisting of six conoids. The spatial distribution of the superconducting phase is shown to be strongly inhomogeneous, with a concentration of the superconducting phase near the narrowest part (the ``neck'') of the bridge. We show that suppression of superconductivity in the bridge by applied magnetic field or by temperature first occurs near the bases and then in the neck region, what leads to a continuous superconducting-to-normal resistive transition. A position of the transition midpoint depends on temperature and, typically, is by one order of magnitude higher than the second critical field Hc2. We find that the vortex states can be realized in the bridge at low temperatures T/Tc<=0.6. The vortex states lead to a fine structure of the superconducting-to-normal resistive transition. We also analyze vortex states in the bridge that are characterized by a varying vorticity as a function of the bridge's height.

  15. Mechanical properties of bioresorbable self-reinforced posterior cervical rods.

    Science.gov (United States)

    Savage, Katherine; Sardar, Zeeshan M; Pohjonen, Timo; Sidhu, Gursukhman S; Eachus, Benjamin D; Vaccaro, Alexander

    2014-04-01

    A biomechanical study. To test the mechanical and physical properties of self-reinforced copolymer bioresorbable posterior cervical rods and compare their mechanical properties to commonly used Irene titanium alloy rods. Bioresorbable instrumentation is becoming increasingly common in surgical spine procedures. Compared with metallic implants, bioresorbable implants are gradually reabsorbed as the bone heals, transferring the load from the instrumentation to bone, eliminating the need for hardware removal. In addition, bioresorbable implants produce less stress shielding due to a more physiological modulus of elasticity. Three types of rods were used: (1) 5.5 mm copolymer rods and (2) 3.5 mm and (3) 5.5 mm titanium alloy rods. Four tests were used on each rod: (1) 3-point bending test, (2) 4-point bending test, (3) shear test, and (4) differential scanning calorimeter test. The outcomes were recorded: Young modulus (E), stiffness, maximum load, deflection at maximum load, load at 1.0% strain of the rod's outer surface, and maximum bending stress. The Young modulus (E) for the copolymer rods (mean range, 6.4-6.8 GPa) was significantly lower than the 3.5 mm titanium rods (106 GPa) and the 5.5 mm titanium rods (95 GPa). The stiffness of the copolymer rods (mean range, 16.6-21.4 N/mm) was also significantly lower than the 3.5 mm titanium alloy rods (43.6 N/mm) and the 5.5 mm titanium alloy rods (239.6 N/mm). The mean maximum shear load of the copolymer rods was 2735 N and they had significantly lower mean maximum loads than the titanium rods. Copolymer rods have adequate shear resistance, but less load resistance and stiffness compared with titanium rods. Their stiffness is closer to that of bone, causing less stress shielding and better gradual dynamic loading. Their use in semirigid posterior stabilization of the cervical spine may be considered.

  16. RodPilotR - The Innovative and Cost-Effective Digital Control Rod Drive Control System for PWRs

    International Nuclear Information System (INIS)

    Baron, Clemens

    2008-01-01

    With RodPilot, AREVA NP offers an innovative and cost-effective system for controlling control rods in Pressurized Water Reactors. RodPilot controls the three operating coils of the control rod drive mechanism (lift, moveable gripper and stationary gripper coil). The rods are inserted into or withdrawn from the core as required by the Reactor Control System. The system combines modern components, state-of-the-art logic and a proven electronic control rod drive control principle to provide enhanced reliability and lower maintenance costs. (author)

  17. Nano-Se Assimilation and Action in Poultry and Other Monogastric Animals: Is Gut Microbiota an Answer?

    Science.gov (United States)

    Surai, Peter F.; Kochish, Ivan I.; Velichko, Oksana A.

    2017-12-01

    Recently, a comprehensive review paper devoted to roles of nano-Se in livestock and fish nutrition has been published in the Nanoscale Research Letters. The authors described in great details an issue related to nano-Se production and its possible applications in animal industry and medicine. However, molecular mechanisms of nano-Se action were not described and the question of how nano-Se is converted into active selenoproteins is not resolved. It seems likely that the gut microbiota can convert nano-Se into selenite, H2Se or Se-phosphate with the following synthesis of selenoproteins. This possibility needs to be further studied in detail, and advantages and disadvantages of nano-Se as a source of Se in animal/poultry/fish nutrition await critical evaluations.

  18. Water Assisted Growth of C60 Rods and Tubes by Liquid–Liquid Interfacial Precipitation Method

    Directory of Open Access Journals (Sweden)

    Cheuk-Wai Tai

    2012-06-01

    Full Text Available C60 nanorods with hexagonal cross sections are grown using a static liquid–liquid interfacial precipitation method in a system of C60/m-dichlorobenzene solution and ethanol. Adding water to the ethanol phase leads instead to C60 tubes where both length and diameter of the C60 tubes can be controlled by the water content in the ethanol. Based on our observations we find that the diameter of the rods/tubes strongly depends on the nucleation step. We propose a liquid-liquid interface growth model of C60 rods and tubes based on the diffusion rate of the good C60 containing solvent into the poor solvent as well as on the size of the crystal seeds formed at the interface between the two solvents. The grown rods and tubes exhibit a hexagonal solvate crystal structure with m-dichlorobenzene solvent molecules incorporated into the crystal structure, independent of the water content. An annealing step at 200 °C at a pressure < 1 kPa transforms the grown structures into a solvent-free face centered cubic structure. Both the hexagonal and the face centered cubic structures are very stable and neither morphology nor structure shows any signs of degradation after three months of storage.

  19. Residual stresses in cold drawn ferritic rods

    International Nuclear Information System (INIS)

    Atienza, J.M.; Martinez-Perez, M.L.; Ruiz-Hervias, J.; Mompean, F.; Garcia-Hernandez, M.; Elices, M.

    2005-01-01

    The residual stress state generated by cold-drawing in a ferritic steel rod has been determined. Stress profiles in the three principal directions were measured by neutron and X-ray diffraction and calculated by 3D finite element simulation. The agreement between the simulations and the experimental data is excellent

  20. Piston rod seal for a Stirling engine

    Science.gov (United States)

    Shapiro, Wilbur

    1984-01-01

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

  1. Automatic operation device for control rods

    International Nuclear Information System (INIS)

    Sekimizu, Koichi

    1984-01-01

    Purpose: To enable automatic operation of control rods based on the reactor operation planning, and particularly, to decrease the operator's load upon start up and shutdown of the reactor. Constitution: Operation plannings, demand for the automatic operation, break point setting value, power and reactor core flow rate change, demand for operation interrupt, demand for restart, demand for forecasting and the like are inputted to an input device, and an overall judging device performs a long-term forecast as far as the break point by a long-term forecasting device based on the operation plannings. The automatic reactor operation or the like is carried out based on the long-term forecasting and the short time forecasting is performed by the change in the reactor core status due to the control rod operation sequence based on the control rod pattern and the operation planning. Then, it is judged if the operation for the intended control rod is possible or not based on the result of the short time forecasting. (Aizawa, K.)

  2. Solitary waves on nonlinear elastic rods. I

    DEFF Research Database (Denmark)

    Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.

    1984-01-01

    Acoustic waves on elastic rods with circular cross section are governed by improved Boussinesq equations when transverse motion and nonlinearity in the elastic medium are taken into account. Solitary wave solutions to these equations have been found. The present paper treats the interaction between...

  3. On contact numbers in random rod packings

    NARCIS (Netherlands)

    Wouterse, A.; Luding, Stefan; Philipse, A.P.

    2009-01-01

    Random packings of non-spherical granular particles are simulated by combining mechanical contraction and molecular dynamics, to determine contact numbers as a function of density. Particle shapes are varied from spheres to thin rods. The observed contact numbers (and packing densities) agree well

  4. ABWR-II Core Design with Spectral Shift Rods for Operation with All Control Rods Withdrawn

    International Nuclear Information System (INIS)

    Moriwaki, Masanao; Aoyama, Motoo; Anegawa, Takafumi; Okada, Hiroyuki; Sakurada, Koichi; Tanabe, Akira

    2004-01-01

    An innovative reactor core concept applying spectral shift rods (SSRs) is proposed to improve the plant economy and the operability of the 1700-MW(electric) Advanced Boiling Water Reactor II (ABWR-II). The SSR is a new type of water rod in which a water level is naturally developed during operation and changed according to the coolant flow rate through the channel. By taking advantage of the large size of the ABWR-II bundle, the enhanced spectral shift operation by eight SSRs allows operation of the ABWR-II with all control rods withdrawn. In addition, the uranium-saving factor of 6 to 7% relative to the reference ABWR-II core with conventional water rods can be expected due to the greater effect of spectral shift. The combination of these advantages means the ABWR-II with SSRs should be an attractive alternative for the next-generation nuclear reactor

  5. Analysis of buffering process of control rod hydraulic absorber

    International Nuclear Information System (INIS)

    Bao Jishi; Qin Benke; Bo Hanliang

    2011-01-01

    Control Rod Hydraulic Drive Mechanism(CRHDM) is a newly invented build-in control rod drive mechanism. Hydraulic absorber is the key part of this mechanism, and is used to cushion the control rod when the rod scrams. Thus, it prevents the control rod from being deformed and damaged. In this paper dynamics program ANSYS CFX is used to calculate all kinds of flow conditions in hydraulic absorber to obtain its hydraulic characteristics. Based on the flow resistance coefficients obtained from the simulation results, fluid mass and momentum equations were developed to get the trend of pressure change in the hydraulic cylinder and the displacement of the piston rod during the buffering process of the control rod. The results obtained in this paper indicate that the hydraulic absorber meets the design requirement. The work in this paper will be helpful for the design and optimization of the control rod hydraulic absorber. (author)

  6. Experimental studies of the effect of rod spacing on burnout in a simulated rod bundle

    International Nuclear Information System (INIS)

    Lee, D.H.; Little, R.B.

    1962-08-01

    Tests on a dumb-bell shaped flow passage simulating the gap between rods in a fuel element indicated that burnout was not significantly affected by inter-rod gap in the range 0.032'' to 0.22''. Test conditions were: 960 p.s.i.a., 2 x 10 6 1b/ft 2 hr mass velocity, and 10% mean exit quality with vertical upflow of water. (author)

  7. Sucker rod string design of the pumping systems

    Directory of Open Access Journals (Sweden)

    Chun Hua Liu

    2015-05-01

    Full Text Available The existing design of sucker rod string mainly focuses on the simplifying assumptions that rod string was exposed to simple tension loading. And its goal was to have equal modified stress at the top of each taper. The improved rod design was to have the same degree of safety at each section, and it used a dynamic force distribution that was proportional along the whole string. However, the available procedures did not provide the desired accuracy of its pertinent analysis, and the operators could not identify the specific phenomena that occur in CBM wells. In this paper, the mathematical models of rod loads and string length were developed based on the cyclic nature of rod string loading; the fatigue endurance method is used to design the single rod string; and the tapered rod string is designed to have an equal equivalent stress at the top of each section. Its application characteristics are demonstrated by the example of CBM wells in Ordos Basin. The interpretations of results show that the previous design gave the single rods a larger diameter and the top rods in the string a greater percent than the proposed method. The calculation should concern about inertial, vibration and friction forces to illustrate the elastic force waves travelling in the rod material with the speed of sound. The single string should be designed using fatigue endurance ratings due to asymmetric pulsating tension of rod loading; and the tapered string should involve a balanced design by setting the fatigue endurance at each section equal. A shorter stroke length gives a greater rod taper percentage and an increased load capacity results to an enhanced rod diameter. The rod diameter increases with the pump size and load capacity for the single string, and the rod taper percentage of the top rod strings increases with plunger diameter for the tapered string. The proposed research improves efficiency of the pumping system, assures good operating conditions, and reduces

  8. Simulation, microstructure and microhardness of the nano-SiC coating formed on Al surface via laser shock processing

    International Nuclear Information System (INIS)

    Cui, C.Y.; Cui, X.G.; Zhao, Q.; Ren, X.D.; Zhou, J.Z.; Liu, Z.; Wang, Y.M.

    2014-01-01

    Highlights: • Nano-SiC coating is successfully fabricated on pure Al surface via LSPC. • Movement states of the nano-SiC particles are analyzed by FEM. • Formation mechanism of the nano-SiC coating is put forward and discussed. • Microhardness of the Al is significantly improved due to the nano-SiC coating. - Abstract: A novel method, laser shock processing coating (LSPC), has been developed to fabricate a particle-reinforced coating based on laser shock processing (LSP). In this study, a nano-SiC coating is successfully prepared on pure Al surface via LSPC. The surface and cross section morphologies as well as the compositions of nano-SiC coating are investigated. Moreover, a finite element method (FEM) is employed to clarify the formation process of nano-SiC coating. On the basis of the above analyzed results, a possible formation mechanism of the nano-SiC coating is tentatively put forward and discussed. Furthermore, the nano-SiC coating shows superior microhardness over the Al substrate

  9. Highly sensitive and selective electrochemical detection of sub-ppb level chromium(VI) using nano-sized gold particle.

    Science.gov (United States)

    Jena, Bikash Kumar; Raj, C Retna

    2008-06-30

    Gold nanoparticle based nanostructured electrode has been developed for the amperometric detection of ultratrace amount of toxic Cr(VI). The nano-sized Au particles have been grown on a conducting substrate modified with sol-gel-derived thiol functionalized silicate network and used for the electroanalysis of Cr(VI). The nanostructured interface show well-defined voltammetric peak for the reduction of Cr(VI) at approximately 0.4 V. The voltammetric behavior of Cr(VI) strongly depends on the coverage of nanoparticle on the electrode surface. Constant potential amperometry has been used for the detection of Cr(VI) at well below the guideline value set by World Health Organization (WHO). This electrode is highly sensitive (30+/-0.2 nA/ppb) and the detection limit (S/N=9) was 0.1 ppb. Cr(III) and coexisting other metal ions and surface active agent present in water do not interfere with the amperometric measurement of Cr(VI). This nanostructured electrode is highly stable and it can be used for continuous measurement of Cr(VI) without using any pretreatment or activation procedures. The accuracy of the measurement has been validated by measuring the concentration of Cr(VI) in the certified reference material (CRM).

  10. Low fluid level in pulse rod shock absorber

    International Nuclear Information System (INIS)

    Aderhold, H.C.

    1974-01-01

    On various occasions during pulse mode operation the shim and regulating control rods would drop when the pulse rod was withdrawn. Subsequent investigation traced the problem to the pulse rod shock absorber which was found to be low in hydraulic fluid. The results of the investigation, the corrective action taken, and a method for measuring the shock absorber fluid level are presented. (author)

  11. Ultrasonics aids the identification of failed fuel rods

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    Over a number of years Brown Boveri Reaktor of West Germany has developed and commercialized an ultrasonic failed fuel rod detection system. Sipping has up to now been the standard technique for failed fuel detection, but sipping can only indicate whether or not an assembly contains defective rods; the BBR system can tell which rod is defective. (author)

  12. 77 FR 1504 - Stainless Steel Wire Rod From India

    Science.gov (United States)

    2012-01-10

    ... COMMISSION Stainless Steel Wire Rod From India Determination On the basis of the record \\1\\ developed in the... antidumping duty order on stainless steel wire rod From India would be likely to lead to continuation or... contained in USITC Publication 4300 (January 2012), entitled Stainless Steel Wire Rod From India...

  13. ROD INTERNAL PRESSURE QUANTIFICATION AND DISTRIBUTION ANALYSIS USING FRAPCON

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Kostadin [Pennsylvania State University, University Park; Jessee, Matthew Anderson [ORNL

    2016-01-01

    The discharge rod internal pressure (RIP) and cladding hoop stress (CHS) distributions are quantified forWatts BarNuclearUnit 1 (WBN1) fuel rods by modeling core cycle design data, intercycle assembly movements, operation data (including modeling significant trips and downpowers), and as-built fuel enrichments and densities of each fuel rod in FRAPCON-3.5. An alternate model for the amount of helium released from zirconium diboride (ZrB2) integral fuel burnable absorber (IFBA) layers is derived and applied to FRAPCON output data to quantify the RIP and CHS for these fuel rods. SCALE/Polaris is used to quantify fuel rod-specific spectral quantities and the amount of gaseous fission products produced in the fuel for use in FRAPCON inputs. Fuel rods with ZrB2 IFBA layers (i.e., IFBA rods) are determined to have RIP predictions that are elevated when compared to fuel rod without IFBA layers (i.e., standard rods) despite the fact that IFBA rods often have reduced fill pressures and annular fuel blankets. Cumulative distribution functions (CDFs) are prepared from the distribution of RIP predictions for all standard and IFBA rods. The provided CDFs allow for the determination of the portion of WBN1 fuel rods that exceed a specified RIP limit. Lastly, improvements to the computational methodology of FRAPCON are proposed.

  14. Local Electronic And Dielectric Properties at Nanosized Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bonnell, Dawn A. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2015-02-23

    Final Report to the Department of Energy for period 6/1/2000 to 11/30/2014 for Grant # DE-FG02-00ER45813-A000 to the University of Pennsylvania Local Electronic And Dielectric Properties at Nanosized Interfaces PI: Dawn Bonnell The behavior of grain boundaries and interfaces has been a focus of fundamental research for decades because variations of structure and composition at interfaces dictate mechanical, electrical, optical and dielectric properties in solids. Similarly, the consequence of atomic and electronic structures of surfaces to chemical and physical interactions are critical due to their implications to catalysis and device fabrication. Increasing fundamental understanding of surfaces and interfaces has materially advanced technologies that directly bear on energy considerations. Currently, exciting developments in materials processing are enabling creative new electrical, optical and chemical device configurations. Controlled synthesis of nanoparticles, semiconducting nanowires and nanorods, optical quantum dots, etc. along with a range of strategies for assembling and patterning nanostructures portend the viability of new devices that have the potential to significantly impact the energy landscape. As devices become smaller the impact of interfaces and surfaces grows geometrically. As with other nanoscale phenomena, small interfaces do not exhibit the same properties as do large interfaces. The size dependence of interface properties had not been explored and understanding at the most fundamental level is necessary to the advancement of nanostructured devices. An equally important factor in the behavior of interfaces in devices is the ability to examine the interfaces under realistic conditions. For example, interfaces and boundaries dictate the behavior of oxide fuel cells which operate at extremely high temperatures in dynamic high pressure chemical environments. These conditions preclude the characterization of local properties during fuel cell

  15. Transient rod failure in a pulsing TRIGA Mark I reactor

    International Nuclear Information System (INIS)

    Draper, E.L. Jr.; Atkinson, G.D. Jr.

    1972-01-01

    Full text: On July 7, 1970 the University of Texas at Austin TRIGA Mark I Pulsing Reactor experienced a failure of the transient control rod. Although no danger to personnel or damage to the reactor other than the pulse rod occurred, the failure was promptly reported to the USAEC regional compliance office. The first indication of an abnormal situation was unusual multiplication behavior during the first start-up of the day. As usual for steady state operation, the operator removed the transient rod and began to withdraw the shim and regulating rods. After partial withdrawal, he noticed that the count rate was not increasing as rapidly as was customary. While remaining at the console,the operator had a technician make a visual inspection of the core. The technician observed the transient drive rod was swinging freely in the pool and the poison section was detached. It was concluded, based on the indications of the.reactor instrumentation and visual inspection, that the transient control rod had broken off and remained in position in the core. The regulating and shim rods were inserted and the transient rod was manually cranked to the down position. The manual manipulation of the transient rod, instead of dropping the rod by gravity, was used so that the connecting rod could be reinserted in the control rod guide tube. The reactor core was then partially unloaded so that a critical mass was not present. The transient rod drive and connecting rod were removed from the pool. The poison section was retrieved from its position in the core by welding a tap to a long rod and tapping into the top of the poison section. Visual inspection of the poison section showed that the weld joining the male threads on the poison section to the main body of the control rod had failed. The threads remained screwed in the control rod drive shaft upon separation and the poison section remained fully inserted in the core. A new control rod was fabricated by Gulf General Atomic and shipped

  16. Rebirth of a control rod at the Phenix power plant

    International Nuclear Information System (INIS)

    De Carvalho, Corinne; Vignau, Bernard; Masson, Marc

    2007-01-01

    This paper outlines the operations involved in cleaning the control rod for the complementary shutdown system in the Phenix Power Plant, the French sodium-cooled fast reactor. The Phenix reactor is controlled by six control rods and a complementary shutdown system. The latter comprises a control rod and a mechanism maintaining the rod in position by means of an electromagnet. The electromagnet is continuously supplied with power and holds the rod control assembly in position by magnetisation on a plane circular surface made from pure iron. The bearing capacity of the mechanism on the rod was initially 80 daN with a rod weight of 26.3 daN. This deteriorated progressively over time. The bearing surface of the rod and the electromagnet became contaminated with a deposit of sodium oxides and metallic particles, thus creating an air gap. This reached a figure of 36 daN in 2005 and was deemed not to be sufficient to prevent the rod from dropping at the wrong time during reactor operation. The Power Plant thus decided to replace the rod mechanism in the reactor in an initial phase, followed by the control rod itself. As the Phenix Power Plant had no spare control rods left, they initiated a 'salvage' plan, over two stages, for the rod removed from the reactor and placed in the fuel storage drum: - Inspection of the bearing surface of the rod by means of a borescope to check whether the rod could be salvaged, - A cleaning operation on the bearing face and checks on the bearing capacity of the rod. The operation is subject to very stringent requirements: the rod must not be taken out of the sodium to ensure that it can be reused in the reactor. The operation must thus take place in the fuel storage drum where there are no facilities for such an operation and where operating conditions are very hostile: high temperatures (the sodium in the fuel storage drum is at a temperature of 150 deg. C, high dose rate (3 mGy/h on the bearing surface) and the bearing surface is submerged

  17. Modeling of microcrack density based damage evolution in ceramic rods

    International Nuclear Information System (INIS)

    Grove, D.J.; Rajendran, A.M.

    2000-01-01

    This paper presents results from simulations of shock wave propagation in ceramic rods with and without confinement. The experiments involved steel and graded-density flyer plates impacting sleeved and unsleeved AD995 ceramic rods. The main objectives of simulating these experiments were: 1) to validate the Rajendran-Grove (RG) ceramic model constants, and 2) to investigate the effects of confinement on damage evolution in ceramic rods, as predicted by the RG model. While the experimental measurements do not indicate the details of damage evolution in the ceramic rod, the numerical modeling has provided some valuable insight into the damage initiation and propagation processes in ceramic rods

  18. Measurement and analysis of CEFR safety and shim rod worth

    International Nuclear Information System (INIS)

    Chen Yiyu; Yang Yong; Gang Zhi; Xu Li; Yang Xiaoyan; Zhou Keyuan; Hu Dingsheng

    2013-01-01

    The reactivity worth of safety rods and shim rods in critical phase and operating phase was calculated respectively using Monte Carlo program in this paper. In addition, the reactivity worth of safety rods and shim rods was measured by the rod drop-off method and period method. The experimental results are in good agreement with the calculated values with less than 5% error. It illustrates the high calculation precision of Monte Carlo program, which provides a practical reference for subsequent application of Monte Carlo program in future demonstration fast reactors. (authors)

  19. Composites reinforcement by rods a SAS study

    CERN Document Server

    Urban, V; Pyckhout-Hintzen, W; Richter, D; Straube, E

    2002-01-01

    The mechanical properties of composites are governed by size, shape and dispersion degree of so-called reinforcing particles. Polymeric fillers based on thermodynamically driven microphase separation of block copolymers offer the opportunity to study a model system of controlled rod-like filler particles. We chose a triblock copolymer (PBPSPB) and carried out SAS measurements with both X-rays and neutrons, in order to characterize separately the hard phase and the cross-linked PB matrix. The properties of the material depend strongly on the way that stress is carried and transferred between the soft matrix and the hard fibers. The failure of the strain-amplification concept and the change of topological contributions to the free energy and scattering factor have to be addressed. In this respect the composite shows a similarity to a two-network system, i.e. interpenetrating rubber and rod-like filler networks. (orig.)

  20. [Rod of Asclepius. Symbol of medicine].

    Science.gov (United States)

    Young, Pablo; Finn, Bárbara C; Bruetman, Julio E; Cesaro Gelos, Jorge; Trimarchi, Hernán

    2013-09-01

    Symbolism is one of the most archaic forms of human thoughts. Symbol derives from the Latin word symbolum, and the latter from the Greek symbolon or symballo, which means "I coincide, I make matches". The Medicine symbol represents a whole series of historical and ethical values. Asclepius Rod with one serpent entwined, has traditionally been the symbol of scientific medicine. In a misconception that has lasted 500 years, the Caduceus of Hermes, entwined by two serpents and with two wings, has been considered the symbol of Medicine. However, the Caduceus is the current symbol of Commerce. Asclepius Rod and the Caduceus of Hermes represent two professions, Medicine and Commerce that, in ethical practice, should not be mixed. Physicians should be aware of their real emblem, its historical origin and meaning.

  1. Experience with a fuel rod enrichment scanner

    International Nuclear Information System (INIS)

    Kubik, R.N.; Pettus, W.G.

    1975-01-01

    This enrichment scanner views all fuel rods produced at B and W's Commercial Nuclear Fuel Plant. The scanner design is derived from the PAPAS System reported by R. A. Forster, H. D. Menlove, and their associates at Los Alamos. The spatial resolution of the system and smoothing of the data are discussed in detail. The cost-effectiveness of multi-detector versus single detector scanners of this general design is also discussed

  2. Synthesis of disk-on-rod antennas

    Science.gov (United States)

    Dubrovka, F. F.; Lenivenko, V. A.

    1993-05-01

    The analysis and synthesis of disk-on-rod antennas (DORAs) with canonical and stepwise disk shapes are considered. A comparison of theoretical and experimental results shows that mathematical models and software developed by solving the appropriate boundary value problems can be used for the design of optimal DORAs. A broadband centimeter-wave DORA is considered as an example of the application of the proposed method for the constructive synthesis of DORAs using multicriterial optimization.

  3. Multiphoton response of retinal rod photoreceptors

    Directory of Open Access Journals (Sweden)

    Vasilios Alexiades

    2007-02-01

    Full Text Available Phototransduction is the process by which light is converted into an electrical response in retinal photoreceptors. Rod photoreceptors contain a stack of (about 1000 disc membranes packed with photopigment rhodopsin molecules, which absorb the photons. We present computational experiments which show the profound effect on the response of the distances (how many discs apart photons happen to be absorbed at. This photon-distribution effect alone can account for much of the observed variability in response.

  4. Rod Driven Frequency Entrainment and Resonance Phenomena

    Directory of Open Access Journals (Sweden)

    Christina Salchow

    2016-08-01

    Full Text Available A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α of each volunteer in the range from 0.40–2.30*α. 306-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90–1.10*α and half of the alpha frequency (0.40–0.55*α. No signs of resonance and frequency entrainment phenomena were revealed around 2.00*α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30–2.30*α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex.

  5. Hydrodynamic behavior of a bare rod bundle

    International Nuclear Information System (INIS)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers

  6. Analysis of Double-encapsulated Fuel Rods

    Energy Technology Data Exchange (ETDEWEB)

    Hales, Jason Dean [Idaho National Laboratory; Medvedev, Pavel G [Idaho National Laboratory; Novascone, Stephen Rhead [Idaho National Laboratory; Perez, Danielle Marie [Idaho National Laboratory; Williamson, Richard L [Idaho National Laboratory

    2014-09-01

    In an LWR fuel rod, the cladding encapsulates the fuel, contains fission products, and transfers heat directly to the water coolant. In some situations, it may be advantageous to separate the cladding from the coolant through use of a secondary cladding or capsule. This may be done to increase confidence that the fuel or fission products will not mix with the coolant, to provide a mechanism for controlling the rod temperature, or to place multiple experimental rodlets within a single housing. With an axisymmetric assumption, it is possible to derive closed-form expressions for the temperature profile in a fuel rod using radially-constant thermal conductivity in the fuel. This is true for both a traditional fuel-cladding rod and a double-encapsulated fuel (fuel, cladding, capsule) configuration. Likewise, it is possible to employ a fuel performance code to analyse both a traditional and a double-encapsulated fuel. In the case of the latter, two sets of gap heat transfer conditions must be imposed. In this work, we review the equations associated with radial heat transfer in a cylindrical system, present analytic and computational results for a postulated power and gas mixture history for IFA-744, and describe the analysis of the AFC-2A, 2B metallic fuel alloy experiments at the Advanced Test Reactor, including the effect of a release of fission products into the cladding-capsule gap. The computational results for these two cases were obtained using BISON, a fuel performance code under development at Idaho National Laboratory.

  7. Effective delivery of recombinant proteins to rod photoreceptors via lipid nanovesicles

    Energy Technology Data Exchange (ETDEWEB)

    Asteriti, Sabrina [Dept. of Translational Research, University of Pisa, Pisa (Italy); Dal Cortivo, Giuditta [Dept. of Life Sciences and Reproduction, University of Verona, Strada Le Grazie 8, Verona (Italy); Pontelli, Valeria [Dept. of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona (Italy); Cangiano, Lorenzo [Dept. of Translational Research, University of Pisa, Pisa (Italy); Buffelli, Mario, E-mail: mario.buffelli@univr.it [Dept. of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona (Italy); Center for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona (Italy); Dell’Orco, Daniele, E-mail: daniele.dellorco@univr.it [Dept. of Life Sciences and Reproduction, University of Verona, Strada Le Grazie 8, Verona (Italy); Center for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona (Italy)

    2015-06-12

    The potential of liposomes to deliver functional proteins in retinal photoreceptors and modulate their physiological response was investigated by two experimental approaches. First, we treated isolated mouse retinas with liposomes encapsulating either recoverin, an important endogenous protein operating in visual phototransduction, or antibodies against recoverin. We then intravitrally injected in vivo liposomes encapsulating either rhodamin B or recoverin and we investigated the distribution in retina sections by confocal microscopy. The content of liposomes was found to be released in higher amount in the photoreceptor layer than in the other regions of the retina and the functional effects of the release were in line with the current model of phototransduction. Our study sets the basis for quantitative investigations aimed at assessing the potential of intraocular protein delivery via biocompatible nanovesicles, with promising implications for the treatment of retinal diseases affecting the photoreceptor layer. - Highlights: • Recombinant proteins encapsulated in nano-sized liposomes injected intravitreally reach retinal photoreceptors. • The phototransduction cascade in rods is modulated by the liposome content. • Mathematical modeling predicts the alteration of the photoresponses following liposome fusion.

  8. Kinetics of folding of the myosin rod.

    Science.gov (United States)

    Bechet, J J; Nozais, M

    1997-02-15

    The kinetics of the unfolding and refolding of the myosin rod have been studied by fluorescence and circular dichroism techniques, at different concentrations of protein and guanidine hydrochloride. The unfolding of the myosin rod was fast and at least biphasic in 2-3 M denaturant, with an initial immediate phase followed by a slower low-amplitude first-order phase. The refolding of the rod in 0.4-2 M guanidine hydrochloride was also at least biphasic; an initial immediate phase preceded a slow second-order phase. At the final denaturant concentration of 0.8 M, the amplitude of the burst phase was weakly dependent on the protein concentration and the rate constant of the refolding slow phase was optimal. These data are incorporated into a folding mechanism with at least three states. The high rates of the first steps of unfolding and refolding may be relevant for the functioning of the native myosin molecule by allowing a transient separation of the two strands of the myosin tail.

  9. Removable control rod drive shaft guide

    International Nuclear Information System (INIS)

    Ales, M.W.; Brown, S.K.; Dixon, L.D.

    1988-01-01

    A removable control rod drive shaft guide is described for a control rod ''guide'' structure card, comprising: a. a substantially annular shaped main body portion having a central axial bore for receiving a control rod drive shaft and an upper exterior groove for receiving removal tooling; b. the main body portion having a reduced outer diameter at its lower section; c. a shoulder portion integral with the main body portion for supporting the main body portion on the guide structure card; d. the shoulder portion having a substantially radial bore and the reduced outer diameter lower section having a slot in alignment with the radial bore; e. a locking arm ''pivotaly'' mounted in the radial bore which protrudes into the slot and is movable between a first normal locking position for engaging the guide structure card and a second release position; f. a spring received within a second axial bore in the main body portion and biased against the locking arm for urging and locking arm into the first normal locking position; and g. a release tab at one end of the locking arm for moving the locking arm into the second release position

  10. Incorporation of squalene into rod outer segments

    International Nuclear Information System (INIS)

    Keller, R.K.; Fliesler, S.J.

    1990-01-01

    We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from [ 3 H]acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms

  11. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    Science.gov (United States)

    Young, J.N.

    1957-08-20

    An electromagnetic device for moving an object in a linear path by increments is described. The device is specifically adapted for moving a neutron absorbing control rod into and out of the core of a reactor and consists essentially of an extension member made of magnetic material connected to one end of the control rod and mechanically flexible to grip the walls of a sleeve member when flexed, a magnetic sleeve member coaxial with and slidable between limit stops along the flexible extension, electromagnetic coils substantially centrally located with respect to the flexible extension to flex the extension member into gripping engagement with the sleeve member when ener gized, moving electromagnets at each end of the sleeve to attract the sleeve when energized, and a second gripping electromagnet positioned along the flexible extension at a distance from the previously mentioned electromagnets for gripping the extension member when energized. In use, the second gripping electromagnet is deenergized, the first gripping electromagnet is energized to fix the extension member in the sleeve, and one of the moving electromagnets is energized to attract the sleeve member toward it, thereby moving the control rod.

  12. Freon 7-rod cluster subchannel mixing experiments

    International Nuclear Information System (INIS)

    Bowring, R.W.; Levy, L.

    1969-12-01

    The subchannel thermal-hydraulic characteristics of a 7-rod cluster were measured using boiling freon-12, modelling water at 1,000 psia. The heated length was 36 inches, the rod diameter 0.625 inches and rod gap 0.060 inches. The following were determined from the experiments: lateral resistance to cross-flow, the diversion length, cross-flow enthalpy, the fraction of heat retained in the highly rated subchannel and the turbulent mixing factor, F m , used in HAMBO. The mixing factor was found to decrease when boiling started but was then independent of vapour quality, within the experimental error. It also decreased more rapidly with mass velocity in the boiling than in the non-boiling regime. The cross-flow enthalpy was found to be a continuous function with cross-flow and not that of the donor subchannel; the enthalpy appeared to be intermediate between that of the two subchannels but the possibility of steam enhancement could not be discounted. (author)

  13. Analytical prediction of turbulent friction factor for a rod bundle

    International Nuclear Information System (INIS)

    Bae, Jun Ho; Park, Joo Hwan

    2011-01-01

    An analytical calculation has been performed to predict the turbulent friction factor in a rod bundle. For each subchannel constituting a rod bundle, the geometry parameters are analytically derived by integrating the law of the wall over each subchannel with the consideration of a local shear stress distribution. The correlation equations for a local shear stress distribution are supplied from a numerical simulation for each subchannel. The explicit effect of a subchannel shape on the geometry parameter and the friction factor is reported. The friction factor of a corner subchannel converges to a constant value, while the friction factor of a central subchannel steadily increases with a rod distance ratio. The analysis for a rod bundle shows that the friction factor of a rod bundle is largely affected by the characteristics of each subchannel constituting a rod bundle. The present analytic calculations well predict the experimental results from the literature with rod bundles in circular, hexagonal, and square channels.

  14. Description and characterization of HBWR Series H-1 test rods

    International Nuclear Information System (INIS)

    Wagoner, S.R.; Barner, J.O.; Welty, R.K.

    1979-06-01

    The as-built characterization results are presented for the HBWR Series H-1 test rods to be irradiated as part of the Fuel Performance Improvement Program (FPIP). The irradiation of these rods is to be conducted in the Halden Boiling Water Reactor (HBWR). Series H-1 consists of twelve rods for irradiation and six spares. Rod design types include (1) a reference dished pellet design, (2) an annular pellet design, (3) an annular pellet design combined with graphite-coated cladding, and (4) a packed-particle (vipac) design. The report, which describes the fabrication and detailed characterization results for the rods, is divided into four major sections: (1) experiment description, (2) process development required to fabricate the test rods, (3) methods and procedures used to fabricate and characterize the rods, and (4) a summary of the characterization results

  15. Characterisation and Treatment of Nano-sized Particles, Colloids and Associated Polycyclic Aromatic Hydrocarbons in Stormwater

    DEFF Research Database (Denmark)

    Nielsen, Katrine

    . The associated pollutants will, if not removed in stormwater treatment facilities, be discharged into receiving surface waters, due to enhanced transportation exerted by the colloids and nano-sized particles. More stormwater than previously is separated from wastewater and drained to stormwater treatment.......Since little is known about the colloids and nano-sized particle-enhanced transportation of pollutants in stormwater, it has been difficult to determine their quantitative role in the total release of pollutants into receiving waters.Therefore the main purpose of this thesis has been to document the presence...... and size distribution of colloids and nano-sized particles in stormwater, as well as quantify the particle-enhanced transportation of polycyclic aromatic hydrocarbons (PAHs) in stormwater. Stormwater from five sites in Europe was collected to characterise the particulate matter, colloids and nano...

  16. Grown on Novel Microcarriers

    Directory of Open Access Journals (Sweden)

    Torsten Falk

    2012-01-01

    Full Text Available Human retinal pigment epithelial (hRPE cells have been tested as a cell-based therapy for Parkinson’s disease but will require additional study before further clinical trials can be planned. We now show that the long-term survival and neurotrophic potential of hRPE cells can be enhanced by the use of FDA-approved plastic-based microcarriers compared to a gelatin-based microcarrier as used in failed clinical trials. The hRPE cells grown on these plastic-based microcarriers display several important characteristics of hRPE found in vivo: (1 characteristic morphological features, (2 accumulation of melanin pigment, and (3 high levels of production of the neurotrophic factors pigment epithelium-derived factor (PEDF and vascular endothelial growth factor-A (VEGF-A. Growth of hRPE cells on plastic-based microcarriers led to sustained levels (>1 ng/ml of PEDF and VEGF-A in conditioned media for two months. We also show that the expression of VEGF-A and PEDF is reciprocally regulated by activation of the GPR143 pathway. GPR143 is activated by L-DOPA (1 μM which decreased VEGF-A secretion as opposed to the previously reported increase in PEDF secretion. The hRPE microcarriers are therefore novel candidate delivery systems for achieving long-term delivery of the neuroprotective factors PEDF and VEGF-A, which could have a value in neurodegenerative conditions such as Parkinson’s disease.

  17. Between a Map and a Data Rod

    Science.gov (United States)

    Teng, William; Rui, Hualan; Strub, Richard; Vollmer, Bruce

    2015-01-01

    A Digital Divide has long stood between how NASA and other satellite-derived data are typically archived (time-step arrays or maps) and how hydrology and other point-time series oriented communities prefer to access those data. In essence, the desired method of data access is orthogonal to the way the data are archived. Our approach to bridging the Divide is part of a larger NASA-supported data rods project to enhance access to and use of NASA and other data by the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System (HIS) and the larger hydrology community. Our main objective was to determine a way to reorganize data that is optimal for these communities. Two related objectives were to optimally reorganize data in a way that (1) is operational and fits in and leverages the existing Goddard Earth Sciences Data and Information Services Center (GES DISC) operational environment and (2) addresses the scaling up of data sets available as time series from those archived at the GES DISC to potentially include those from other Earth Observing System Data and Information System (EOSDIS) data archives. Through several prototype efforts and lessons learned, we arrived at a non-database solution that satisfied our objectivesconstraints. We describe, in this presentation, how we implemented the operational production of pre-generated data rods and, considering the tradeoffs between length of time series (or number of time steps), resources needed, and performance, how we implemented the operational production of on-the-fly (virtual) data rods. For the virtual data rods, we leveraged a number of existing resources, including the NASA Giovanni Cache and NetCDF Operators (NCO) and used data cubes processed in parallel. Our current benchmark performance for virtual generation of data rods is about a years worth of time series for hourly data (9,000 time steps) in 90 seconds. Our approach is a specific implementation of

  18. Neuro-oncologic applications of exosomes, microvesicles, and other nano-sized extracellular particles.

    Science.gov (United States)

    Gonda, David D; Akers, Johnny C; Kim, Ryan; Kalkanis, Steven N; Hochberg, Fred H; Chen, Clark C; Carter, Bob S

    2013-04-01

    The discovery that tumor-derived proteins and nucleic acids can be detected in nano-sized vesicles in the plasma and cerebrospinal fluid of patients afflicted with brain tumors has expanded opportunities for biomarker and therapeutic discovery. Through delivery of their contents to surrounding cells, exosomes, microvesicles, and other nano-sized extracellular vesicles secreted by tumors modulate their environment to promote tumor growth and survival. In this review, we discuss the biological processes mediated by these extracellular vesicles and their applications in terms of brain tumor diagnosis, monitoring, and therapy. We review the normal physiology of these extracellular vesicles, their pertinence to tumor biology, and directions for research in this field.

  19. Nanosizing a Metal-Organic Framework Enzyme Carrier for Accelerating Nerve Agent Hydrolysis.

    Science.gov (United States)

    Li, Peng; Moon, Su-Young; Guelta, Mark A; Lin, Lu; Gómez-Gualdrón, Diego A; Snurr, Randall Q; Harvey, Steven P; Hupp, Joseph T; Farha, Omar K

    2016-10-05

    We report the synthesis and characterization of a water-stable zirconium metal-organic framework (MOF), NU-1003, featuring the largest mesoporous aperture known for a zirconium MOF. This material has been used to immobilize the nerve agent hydrolyzing enzyme, organophosphorus acid anhydrolase (OPAA). The catalytic efficiency of immobilized OPAA in nanosized NU-1003 is significantly increased compared to that of OPAA immobilized in microsized NU-1003 and even exceeds that of the free OPAA enzyme. This paper highlights a method for rapid and highly efficient hydrolysis of nerve agents using nanosized enzyme carriers.

  20. Chemoselective Oxidation of Bio-Glycerol with Nano-Sized Metal Catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Kotni, Ramakrishna; Zhang, Qiuyun

    2015-01-01

    to selectively oxidize glycerol and yield products with good selectivity is the use of nano-sized metal particles as heterogeneous catalysts. In this short review, recent developments in chemoselective oxidation of glycerol to specific products over nano-sized metal catalysts are described. Attention is drawn...... to various reaction parameters such as the type of the support, the size of the metal particles, and the acid/base properties of the reaction medium which were illustrated to largely influence the activity of the nanocatalyst and selectivity to the target product. - See more at: http...

  1. Electrochemical Li-uptake properties of nanosized NiSb2 prepared by solvothermal route

    International Nuclear Information System (INIS)

    Xie, J.; Zhao, X.B.; Cao, G.S.; Zhao, M.J.; Su, S.F.

    2005-01-01

    The nanosized intermetallic compound NiSb 2 was prepared by a solvothermal route and studied as a potential anode material for secondary lithium-ion batteries. The microstructure of the as-prepared NiSb 2 powder was characterized by X-ray diffraction, transmission electron microscopy. The electrochemical performances of the NiSb 2 electrode were investigated by galvanostatic charge and discharge cycling and by cyclic voltammogram. It was found that the nanosized NiSb 2 electrode shows improved cycling behavior, especially in the initial cycles, compared to the micrometer sized NiSb 2 prepared by a levitation-melting/ball-milling route

  2. ''Fabrice'' process for reconstituting experimental rods in a hot cell from pre-irradiated rods in power reactors

    International Nuclear Information System (INIS)

    Houdaille, B.; Vignesoult, N.; Atabek, R.

    1981-11-01

    The Fabrice process for the ''hot cell refabrication'' of small rods from very long irradiated fuel elements was developed by the CEA, particularly to enable parametric studies to be carried out on the behaviour under irradiation of rods from power stations. This technique, although requiring intricate operations in a hot cell with specially adapted equipment and a very experienced personnel, enables (1) a significant saving to be made compared with the pre-irradiation of new rods and (2) affords a virtually unlimited choice of rod sections irradiated in a power reactor for parametric irradiations. Tests have shown that the initial characteristics of the sample rod are not modified and that the behaviour under irradiation of whole non-refabricated rods and Fabrice rods with the same initial characteristics is identical, for a local specific burn-up under 40,000 MWd/t, vis-a-vis the fuel cladding interaction phenomenon [fr

  3. Relation of fuel rod service parameters and design requirements to produced fuel rod and their components

    International Nuclear Information System (INIS)

    Bibilashvili, Yu.K.

    1999-01-01

    Based on the presented material it is possible to state that there is a very close link between the fuel operational parameters and the requirements for its design and production process. The required performance and life-time of a fuel rod can be only assured by the correctly selected design and process solutions. The economical aspect of this problem is significantly depend on the commercial feasibility of a particular selected solution with the provision of an automated and comparative by inexpensive production of a fuel rod and its components. The operational conditions are also important for the life time of the fuel rods. If there are no special measures for the mitigation of the certain operation conditions the leakage of fuel elements can take place before the planned time. (authors)

  4. Shielding device for control rod in nuclear reactor

    International Nuclear Information System (INIS)

    Sakamaki, Kazuo; Tomatsu, Tsutomu.

    1995-01-01

    The device of the present invention shields radiation emitted from control rods to greatly reduce an operator's radiation exposure even if reactor water level is lowered and the upper portion of the control rod is exposed upon inspection of a BWR type reactor. Namely, a shield assembly has a structure comprising a set of four columnar shields in a two-row and two-column arrangement, which can be inserted into a control rod guide tube. Upon conducting inspection, the control rod is lowered into the control rod guide tube, and in this state, the columnar shields of the shield assembly are inserted to the control rod in the control rod guide tube. With such procedures, the upper portion of the control rod protruded from the control rod guide tube is covered with the shield assembly. As a result, radiation leaked from the control rod is shielded. Accordingly, irradiation in the reactor due to leaked radiation can be prevented thereby enabling to reduce an operator's radiation exposure. (I.S.)

  5. Temperature measurement in cans of fuel rods and fuel rod simulators

    International Nuclear Information System (INIS)

    Tschoeke, H.; Moeller, R.

    1977-01-01

    On the sodium-cooled 19-rod cluster model for the SNR 300 the can wall temperature distributions of the non-uniformly cooled rods were measured with thermocouples mounted in outer grooves in the peripheral zone, permitting, in connection with Ni solder, a practically undisturbed measurement. For a more exact determination of the local surface temperature a calibration method, the so-called double-wall method, was developed and applied. The description of this calibration method and the experimental results achieved until now are presented. (orig./RW) [de

  6. Sucker-rod pumping handbook production engineering fundamentals and long-stroke rod pumping

    CERN Document Server

    Takacs, Gabor

    2015-01-01

    Sucker-Rod Pumping Handbook presents the latest information on the most common form of production enhancement in today's oil industry, making up roughly two-thirds of the producing oilwell operations in the world. The book begins with an introduction to the main features of sucker rod pumping and an explanation and comparison of lift methods. It goes on to provide the technical and practical knowledge needed to introduce the new and practicing production engineer and operator to the equipment, technology, and applications required to maintain optimum operating conditions.

  7. Mixing of nanosize particles by magnetically assisted impaction techniques

    Science.gov (United States)

    Scicolone, James V.

    Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other high-value-added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary. Due to high surface area, nano-particles form very large, fractal agglomerates. The structure of these agglomerates can have a large agglomerate composed of sub-agglomerates (SA), which itself consists of primary agglomerates (PA), that contain chain or net like nano-particle structures; typically sub-micron size. Thus the final agglomerate has a hierarchical, fractal structure, and depending upon the forces applied, it could break down to a certain size scale. The agglomerates can be fairly porous and fragile or they could be quite dense, based on primary particle size and its surface energy. Thus depending upon the agglomerate strength at different length scales, one could achieve deagglomeration and subsequent mixing at varying length scale. A better understanding of this can have a major impact on the field of nano-structured materials; thus the long term objective of this project is to gain fundamental understanding of deagglomeration and mixing of nano-agglomerates. Dry mixing is in general not effective in achieving desired mixing at nanoscale, whereas wet mixing suffers from different disadvantages like nanomaterial of interest should be insoluble, has to wet the liquid, and involves additional steps of filtration and drying. This research examines the use of environmentally friendly a novel

  8. Simulation of nuclear fuel rods by using process computer-controlled power for indirect electrically heated rods

    International Nuclear Information System (INIS)

    Malang, S.

    1975-11-01

    An investigation was carried out to determine how the simulation of nuclear fuel rods with indirect electrically heated rods could be improved by use of a computer to control the electrical power during a loss-of-coolant accident (LOCA). To aid in the experiment, a new version of the HETRAP code was developed which simulates a LOCA with heater rod power controlled by a computer that adjusts rod power during a blowdown to minimize the difference in heat flux of the fuel and heater rods. Results show that without computer control of heater rod power, only the part of a blowdown up to the time when the heat transfer mode changes from nucleate boiling to transition or film boiling can be simulated well and then only for short times. With computer control, the surface heat flux and temperature of an electrically heated rod can be made nearly identical to that of a reactor fuel rod with the same cooling conditions during much of the LOCA. A small process control computer can be used to achieve close simulation of a nuclear fuel rod with an indirect electrically heated rod

  9. Electronic circuit for control rod attracting electromagnet

    International Nuclear Information System (INIS)

    Ito, Koji.

    1991-01-01

    The present invention provides a discharging circuit for control rod attracting electromagnet used for a reactor which is highly reliable and has high performance. The resistor of the circuit comprises a non-linear resistor element and a blocking rectification element connected in series. The discharging circuit can be prevented from short-circuit by selecting a resistor having a resistance value about ten times as great as the coil resistance, even in a case where the blocking rectification element and the non-linear resistor element are failed. Accordingly, reduction of attracting force and the increase of scream releasing time can be minimized. (I.S.)

  10. Minimization of PWR reactor control rods wear

    International Nuclear Information System (INIS)

    Ponzoni Filho, Pedro; Moura Angelkorte, Gunther de

    1995-01-01

    The Rod Cluster Control Assemblies (RCCA's) of Pressurized Water Reactors (PWR's) have experienced a continuously wall cladding wear when Reactor Coolant Pumps (RCP's) are running. Fretting wear is a result of vibrational contact between RCCA rodlets and the guide cards which provide lateral support for the rodlets when RCCA's are withdrawn from the core. A procedure is developed to minimize the rodlets wear, by the shuffling and axial reposition of RCCA's every operating cycle. These shuffling and repositions are based on measurement of the rodlet cladding thickness of all RCCA's. (author). 3 refs, 2 figs, 2 tabs

  11. 4-rod RFQ linac for ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Hiroshi; Hamamoto, Nariaki; Inouchi, Yutaka [Nisshin Electric Co. Ltd., Kyoto (Japan)

    1997-03-01

    A 34 MHz 4-rod RFQ linac system has been upgraded in both its rf power efficiency and beam intensity. The linac is able to accelerate in cw operation 0.83 mA of a B{sup +} ion beam from 0.03 to 0.91 MeV with transmission of 61 %. The rf power fed to the RFQ is 29 kW. The unloaded Q-value of the RFQ has been improved approximately 61 % to 5400 by copper-plating stainless steel cooling pipes in the RFQ cavity. (author)

  12. Maintenance of BWR control rod drive mechanisms

    International Nuclear Information System (INIS)

    Greene, R.H.

    1991-01-01

    Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper

  13. Protector predominantly for pump sucker rods

    Energy Technology Data Exchange (ETDEWEB)

    Razhetdinov, U.Z.; Prokopov, O.I.; Sharafutdinov, I.G.; Valishim, Yu.G.

    1982-01-01

    A protector is proposed which includes a cylindrical housing with connecting threaded sections on the ends and rim with spheres attached to the outer surface of the housing. In order to improve reliable operation of the protector by reducing wear of the rocking supports, the rim on the outer surface of the housing is installed at an angle to its axis with the possibility of movement of the sphere in the rim around the sucker rods with interaction of them with the pump-compressor pipes.

  14. Performance predictions and manufacturing concerns of burnable poison rods

    International Nuclear Information System (INIS)

    Copeland, R.A.; Buescher, B.J.

    1977-01-01

    Burnable poison rods for reactors designed by B and W consist of low density pellets, composed of boron carbide dispersed in an alumina matrix (Al 2 O 3 --B 4 C), which are contained in Zircaloy-4 tubes. To predict reliable operation of these rods, the irradiation behavior of the components must be known. Performance models were developed based on experimental irradiation data. During rod fabrication, care must be taken to limit the amount of hydrogen in the rod because of the propensity of Zircaloy to hydride in the presence of high levels of hydrogen. Furthermore, the hygroscopic nature of alumina dictates that care must be taken to avoid moisture (a primary source of hydrogen) in the rods. Manufacturing and quality testing procedures have been developed to provide conformance to the design criteria. Examinations have been performed on irradiated burnable poison rods which verify the adequacy of both performance models and manufacturing procedures

  15. Rapid and accurate control rod calibration measurement and analysis

    International Nuclear Information System (INIS)

    Nelson, George W.; Doane, Harry J.

    1990-01-01

    In order to reduce the time needed to perform control rod calibrations and improve the accuracy of the results, a technique for a measurement, analysis, and tabulation of integral rod worths has been developed. A single series of critical rod positions are determined at constant low power to reduce the waiting time between positive period measurements and still assure true stable reactor period data. Reactivity values from positive period measurements and control rod drop measurements are used as input data for a non-linear fit to the expected control rod integral worth shape. With this method, two control rods can be calibrated in about two hours, and integral and differential calibration tables for operator use are printed almost immediately. Listings of the BASIC computer programs for the non-linear fitting and calibration table preparation are provided. (author)

  16. Luminescence properties of YAG:Nd nano-sized ceramic powders ...

    Indian Academy of Sciences (India)

    equipment and crucible material and fabricating large sizes and high neodymium concentrations are difficult. Recent investigations have indicated that YAG:Nd3+ polycrystalline nano-sized ceramic powders are among the most promis- ing materials for solid-state lasers (Skita et al 1991; Ikesue et al 1995; Lu et al 2000a, b, ...

  17. Luminescence properties of YAG:Nd nano-sized ceramic powders ...

    Indian Academy of Sciences (India)

    Nano-sized ceramic powders with weaker aggregation of Nd3+-doped yttrium aluminum garnet. (YAG:Nd3+) ... Under excitation at 488 nm, YAG:Nd3+ nano- ..... Rabinovitch Y, Bogicevic C, Karolak F, Tétard D and Dammak H. 2008 J. Mater. Process Tech. 199 314. Sekino T and Sogabe Y 1993 Rev. Laser Eng. 21 827.

  18. Characterization of nano-size heterogeneities by small-angle-scattering

    International Nuclear Information System (INIS)

    Ohnuma, Masato

    2012-01-01

    Techniques of Small-Angle Neutron and X-ray Scattering (SANS and SAXS) are overviewed from principle to applications. Importance of characterizing composition of nano-size heterogeneity is explained based on the results obtained by combination of SANS and SAXS. (author)

  19. Adsorption study of Pb 2 ions on nanosized SnO2, synthesized by ...

    Indian Academy of Sciences (India)

    Adsorption of Pb2+ ions on combustion derived nanosized SnO2 is studied. The as synthesized SnO2 and lead ions adsorbed SnO2 are characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), and infrared spectroscopic (IR) techniques. The eluent is characterized by atomic absorption spectroscopy ...

  20. Solvent-free synthesis of nanosized hierarchical sodalite zeolite with a multi-hollow polycrystalline structure

    KAUST Repository

    Zeng, Shangjing

    2016-08-03

    A solvent-free route is developed for preparing nanoscale sodalite zeolite with a multi-hollow structure. Furthermore, the synthesis of nanosized hollow sodalite polycrystalline aggregates with a mesoporous structure and high crystallinity is investigated by adding an organosilane surfactant as a mesopore-generating agent.

  1. Nano-sized aerosol classification, collection and analysis--method development using dental composite materials.

    Science.gov (United States)

    Bogdan, Axel; Buckett, Mary I; Japuntich, Daniel A

    2014-01-01

    This article presents a methodical approach for generating, collecting, and analyzing nano-size (1-100 nm) aerosol from abraded dental composite materials. Existing aerosol sampling instruments were combined with a custom-made sampling chamber to create and sample a fresh, steady-state aerosol size distribution before significant Brownian coagulation. Morphological, size, and compositional information was obtained by Transmission Electron Microscopy (TEM). To create samples sizes suitable for TEM analysis, aerosol concentrations in the test chamber had to be much higher than one would typically expect in a dental office, and therefore, these results do not represent patient or dental personnel exposures. Results show that nano-size aerosol was produced by the dental drill alone, with and without cooling water drip, prior to abrasion of dental composite. During abrasion, aerosol generation seemed independent of the percent filler load of the restorative material and the operator who generated the test aerosol. TEM investigation showed that "chunks" of filler and resin were generated in the nano-size range; however, free nano-size filler particles were not observed. The majority of observed particles consisted of oil droplets, ash, and graphitic structures.

  2. Synthesis and characterization of nano-sized CaCO3 in purified diet

    Science.gov (United States)

    Mulyaningsih, N. N.; Tresnasari, D. R.; Ramahwati, M. R.; Juwono, A. L.; Soejoko, D. S.; Astuti, D. A.

    2017-07-01

    The growth and development of animals depend strongly on the balanced nutrition in the diet. This research aims is to characterize the weight variations of nano-sized calcium carbonate (CaCO3) in purified diet that to be fed to animal model of rat. The nano-sized CaCO3 was prepared by milling the calcium carbonate particles for 20 hours at a rotation speed of 1000 rpm and resulting particle size in a range of 2-50 nm. Nano-sized CaCO3 added to purified diet to the four formulas that were identified as normal diet (N), deficiency calcium (DC), rich in calcium (RC), and poor calcium (PC) with containing in nano-sized CaCO3 much as 0.50 %, 0.00 %, 0.75 % and 0.25 % respectively. The nutritional content of the purified diet was proximate analyzed, it resulted as followed moisture, ash, fat, protein, crude fiber. The quantities of chemical element were analyzed by atomic absorption spectrometry (AAS), it resulted iron, magnesium, potassium and calcium. The results showed that N diet (Ca: 16,914.29 ppm) were suggested for healthy rats and RC diet (Ca: 33,696.13 ppm) for conditioned osteoporosis rats. The crystalline phases of the samples that were examined by X-ray diffraction showed that crystalline phase increased with the increasing concentration of CaCO3.

  3. Nanosized aerosols from consumer sprays: experimental analysis and exposure modeling for four commercial products

    Science.gov (United States)

    Lorenz, Christiane; Hagendorfer, Harald; von Goetz, Natalie; Kaegi, Ralf; Gehrig, Robert; Ulrich, Andrea; Scheringer, Martin; Hungerbühler, Konrad

    2011-08-01

    Consumer spray products are already on the market in the cosmetics and household sector, which suggest by their label that they contain engineered nanoparticles (ENP). Sprays are considered critical for human health, because the lungs represent a major route for the uptake of ENP into the human body. To contribute to the exposure assessment of ENP in consumer spray products, we analyzed ENP in four commercially available sprays: one antiperspirant, two shoe impregnation sprays, and one plant-strengthening agent. The spray dispersions were analyzed by inductively coupled plasma mass spectrometry (ICPMS) and (scanning-) transmission electron microscopy ((S)TEM). Aerosols were generated by using the original vessels, and analyzed by scanning mobility particle sizer (SMPS) and (S)TEM. On the basis of SMPS results, the nanosized aerosol depositing in the respiratory tract was modeled for female and male consumers. The derived exposure levels reflect a single spray application. We identified ENP in the dispersions of two products (shoe impregnation and plant spray). Nanosized aerosols were observed in three products that contained propellant gas. The aerosol number concentration increased linearly with the sprayed amount, with the highest concentration resulting from the antiperspirant. Modeled aerosol exposure levels were in the range of 1010 nanosized aerosol components per person and application event for the antiperspirant and the impregnation sprays, with the largest fraction of nanosized aerosol depositing in the alveolar region. Negligible exposure from the application of the plant spray (pump spray) was observed.

  4. Primary particles and their agglomerate formation as modifying risk factors of nonfibrous nanosized dust.

    Science.gov (United States)

    Schneider, J; Walter, D; Brückel, B; Rödelsperger, K

    2013-01-01

    The incidence of certain cancers correlates with the number of dust particles in the air. Nanosized particles differ from coarser particles by their increasing tendency to form agglomerates. The dissociation of biodurable agglomerates after deposition in the alveolar region resulted in a higher toxic potential. Biodurable dusts in the urban and workplace environment were analyzed to determine an effect-relevant exposure parameter. The characterization of the dusts relating to their number of primary particles (P(p)) and agglomerates and aggregates (A + A) was performed by electron microscopy. Diesel soot, toner material, and seven further dust samples in the workplace environment are composed of high numbers of nanosized primary particles (agglomerates. Primary particles of rock, kaoline, and seven further dusts sampled in the workplace are not nanosized. In a multivariate analysis that predicted lung tumor risk, the mass, volume, and numbers of A + A and P(p) per milligram dust were shown to be relevant parameters. Dose-response relationships revealed an increased tumor risk in rats with higher numbers of P(p) in nanosized dust, which occurs unintentionally in the environment.

  5. Elaboration and Characterization of Nano-Sized AlxMoyOz/Al Thermites

    National Research Council Canada - National Science Library

    Comet, M; Spitzer, D

    2006-01-01

    ...) has been developed at the Institut franco-allemand de recherches de Saint Louis (ISL). This process consists of a new sol-gel method nano-sized mixed AlxMoyOz phases whose structure is correlated to the chemical composition...

  6. Enhanced dissolution of nanosize CuO in the presence of meso- and micro-pores

    International Nuclear Information System (INIS)

    Huang, C.-H.; Wang, H. Paul; Huang, H.-L.; Hsiung, T.-L.; Tang, F.-C.

    2007-01-01

    Dissolution of nanosize CuO in the chemical mechanical planarization (CMP) waste water in the presence of micropores (0.74 nm) of Y and mesopores (4 nm) of MCM-41 has been studied by X-ray absorption near edge structure (XANES) spectroscopy in the present work. Since pore openings of Y and MCM-41 are much less than the size of nano-CuO (about 13 nm) in the CMP waste water, CuO is not able to be incorporated directly into the pore systems. At least two reaction paths might be involved in the incorporation process: (1) dissolution of CuO and (2) incorporation of Cu 2+ into Y and MCM-41. Experimentally, during the incorporation process, Y might possess equivalent electric fields of 20-50 V/cm for dissolution of nanosize CuO. Interestingly we found that dissolution of nanosize CuO in the CMP waste water was enhanced, for instance, about 65% and 87% of nanosize CuO were incorporated (as Cu 2+ ) and incorporated into Y and MCM-41, respectively

  7. Nano-Sized Zero Valent Iron and Covalent Organic Polymer Composites for Azo Dye Remediation

    DEFF Research Database (Denmark)

    Mines, Paul D.; Byun, Jeehye; Hwang, Yuhoon

    2014-01-01

    Having superior reductive properties and large surface areas, nanosized zero valent iron (nZVI) is ideal for the degradation of chemicals such as azo dyes and trichloroethylene (TCE). However, immobilization of nZVI is a key parameter in its effectiveness as a chemical degradation agent. In this ...

  8. Application of the ellipsoid modeling of the average shape of nanosized crystallites in powder diffraction

    DEFF Research Database (Denmark)

    Katerinopoulou, Anna; Balic Zunic, Tonci; Lundegaard, Lars Fahl

    2012-01-01

    Anisotropic broadening correction in X-ray powder diffraction by an ellipsoidal formula is applied on samples with nanosized crystals. Two cases of minerals with largely anisotropic crystallite shapes are presented. The properly applied formalism not only improves the fitting of the theoretical...

  9. Design and Performance of Rigid Nanosize Multimetallic Cartwheel Pincer Compounds as Lewis-Acid Catalysts

    NARCIS (Netherlands)

    Koten, G. van; Dijkstra, H.P.; Meijer, M.D.; Patel, J.; Kreiter, R.; Klink, G.P.M. van; Lutz, M.H.; Spek, A.L.; Canty, A.J.

    2001-01-01

    Novel strategies for the preparation of rigid cartwheel pincer metal complexes have been developed. The aromatic backbone of these materials ensures a high rigidity, which is expected to be important for a high retention when these multimetallic nanosize complexes are applied as homogeneous

  10. Formulation of solid nano-sized particles in a gel-forming system

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to novel formulations comprising a plurality of nano-sized solid particles and a gel-forming system, useful e.g. for imaging of the body of a mammal. Also described are kits comprising such formulations and imaging methods utilizing such formulations or kits....

  11. Study on evaluating the reactivity worth of the control rods of the PWR 900 MWe

    International Nuclear Information System (INIS)

    Phan Quoc Vuong; Tran Vinh Thanh; Tran Viet Phu

    2015-01-01

    Control rods of a nuclear reactor are divided into two groups: shut down and power control. Reactivity worth of the control rods depends nonlinearly on the rods' compositions and positions where the rods are inserted into the core. Therefore, calculation of control rod worth is of high important. In this study, we calculated the reactivity worth of the power control rod bank of the Mitsubishi PWR 900 MWe. The results are integral and differential worth calibration of the control rods. (author)

  12. Design of the pulse rod drive mechanism for pulsed reactor

    International Nuclear Information System (INIS)

    You Keyi

    1988-07-01

    The pulse rod drive mechanism is a critical movable device for a pulsed reactor. It is an executor under pulse operations, and it may be used in a shim rod under steady-state operations. The pneumatic-electromechanical driving method is taken in the designing. The structure, operating, calculation of parameters and designing methods of the pulse rod drive mechanism are briefly described in this paper. The testing results of the prototypical mechanism are also presented

  13. Nuclear reactor internals construction and failed fuel rod detection system

    International Nuclear Information System (INIS)

    Frisch, E.; Andrews, H.N.

    1976-01-01

    A system is provided for determining during operation of a nuclear reactor having fluid pressure operated control rod mechanisms the exact location of a fuel assembly with a defective fuel rod. The construction of the reactor internals is simplified in a manner to facilitate the testing for defective fuel rods and the reduce the cost of producing the upper internals of the reactor. 13 claims, 10 drawing figures

  14. Thermal hydraulic performance of naturally aspirated control rod housing assemblies

    International Nuclear Information System (INIS)

    Geiger, G.T.; Randolph, H.W.; Paik, I.K.; Foti, D.J.

    1992-01-01

    Savannah River Site reactors are comprised of heat generating fuel/target assemblies, control rods which regulate reactor power, and heavy water which acts as the coolant and as a moderator. The fuel/target assemblies are cooled by the downflow of heavy water while the control rods are cooled via upflow. Five control rods are grouped with two safety rods in seven-channel assemblies called septifoils. Under normal operating conditions, the reactor power level, radial shape flux and axial power flux are regulated by the positioning of the control rods. The control rods are solid rods of a lithium-aluminum alloy with an thin aluminum outer sheath. Lithium is a good absorber of neutrons and, thus control rod temperatures rise with reactor power. At conditions of sufficiently high reactor power and degraded coolant flow, the control rods could heat sufficiently to cause a metallurigical failure of the sheath leading to molten material coming in contact with water and the possibility of a steam explosion. An accident has been postulated as part of the analysis involving the safety upgrade of Savannah River Site reactors in which the housing is not seated on the pin. Coolant from the upflow pin would not be directed into the housing but, into the moderator space surrounding the housing. Only naturally aspirated cooling due to buoyancy effects would be available to cool the control rods and the coolant mass flow rate would drop significantly from its nominal value. In this study, the mechanisms and limits of cooling heated rods housed in an unseated septifoil are addressed. Experiments were conducted on a shortened, prototypic housing with electrically heated rods to gain an understanding of the phenomena governing the cooling in such a case and develop data which can be used to evaluate predictive models. These experiments are described, their results discussed, and the predictions of current models is presented

  15. Shock analysis on hydraulic drive control rod during scram

    International Nuclear Information System (INIS)

    Song Wei; Qin Benke; Bo Hanliang

    2013-01-01

    Control rod hydraulic drive mechanism (CRHDM) is a new invention of Institute of Nuclear and New Energy Technology of Tsinghua University. The hydraulic absorber buffers the control rod when it scrams. The control rod fast drop impact experiment was conducted and the key parameters of control rod hydraulic buffering performance were obtained. Based on the test results and according to D'Alembert principle, the maximum inertial impact force on the control rod during the fast drop period was applied as equivalent static load force on the control rod. The deformations and stress distributions on the control rod in this worst case were calculated by using finite element software ABAQUS. Calculation results were compared with the experiment results, and it was verified that nonlinear transient dynamics analysis in this problem can be simplified as static analysis. Damage criterion of the control rod fast drop impact process was also given. And it lays foundation for optimal design of the control rod and hydraulic absorber. (authors)

  16. TileCal ROD Hardware and Software Requirements

    CERN Document Server

    Castelo, J; Cuenca, C; Ferrer, A; Fullana, E; Higón, E; Iglesias, C; Munar, A; Poveda, J; Ruiz-Martínez, A; Salvachúa, B; Solans, C; Valls, J A

    2005-01-01

    In this paper we present the specific hardware and firmware requirements and modifications to operate the Liquid Argon Calorimeter (LiArg) ROD motherboard in the Hadronic Tile Calorimeter (TileCal) environment. Although the use of the board is similar for both calorimeters there are still some differences in the operation of the front-end associated to both detectors which make the use of the same board incompatible. We review the evolution of the design of the ROD from the early prototype stages (ROD based on commercial and Demonstrator boards) to the production phases (ROD final board based on the LiArg design), with emphasis on the different operation modes for the TileCal detector. We start with a short review of the TileCal ROD system functionality and then we detail the different ROD hardware requirements for options, the baseline (ROD Demo board) and the final (ROD final high density board). We also summarize the performance parameters of the ROD motherboard based on the final high density option and s...

  17. Fast, accurate control rod calibration using a programmable desk calculator

    International Nuclear Information System (INIS)

    Naugle, N.W.; Randall, John D.

    1972-01-01

    In an attempt to develop a simple least squares program for the rapid calibration of control rods it was necessary to verify that all rods, with the exception of the transient rod, could be accurately defined by a single analytical expression. Since the vertical flux distribution in the core region follows a cosine function, a cosine squared variation was tested. The solution which involves the inversion of a 3 x 3 matrix is performed using a Hewlett Packard Model 9100B programmable desk calculator. The least squares program was applied to a number of control rod calibrations that had previously been analyzed by hand. The agreement was excellent in all cases

  18. Lumped-parameter fuel rod model for rapid thermal transients

    International Nuclear Information System (INIS)

    Perkins, K.R.; Ramshaw, J.D.

    1975-07-01

    The thermal behavior of fuel rods during simulated accident conditions is extremely sensitive to the heat transfer coefficient which is, in turn, very sensitive to the cladding surface temperature and the fluid conditions. The development of a semianalytical, lumped-parameter fuel rod model which is intended to provide accurate calculations, in a minimum amount of computer time, of the thermal response of fuel rods during a simulated loss-of-coolant accident is described. The results show good agreement with calculations from a comprehensive fuel-rod code (FRAP-T) currently in use at Aerojet Nuclear Company

  19. Process development and fabrication for sphere-pac fuel rods

    International Nuclear Information System (INIS)

    Welty, R.K.; Campbell, M.H.

    1981-06-01

    Uranium fuel rods containing sphere-pac fuel have been fabricated for in-reactor tests and demonstrations. A process for the development, qualification, and fabrication of acceptable sphere-pac fuel rods is described. Special equipment to control fuel contamination with moisture or air and the equipment layout needed for rod fabrication is described and tests for assuring the uniformity of the fuel column are discussed. Fuel retainers required for sphere-pac fuel column stability and instrumentation to measure fuel column smear density are described. Results of sphere-pac fuel rod fabrication campaigns are reviewed and recommended improvements for high throughput production are noted

  20. Fatigue behaviour of window and rods

    International Nuclear Information System (INIS)

    Bergeron, J.; Brochard, J.; Cheron, Ch.; Gabriel, F.

    1999-01-01

    The current CEA project pertains to feasibility studies of an internal source of neutrons used for irradiations of various natures. An external source generates the necessary protons thanks to a particle accelerator that delivers a high energy proton beam: 600 MeV, 40 mA. The target is composed of rod assemblies and the spallation material is lead contained in aluminium cladding cooled by low pressured tepid water. The interface between the accelerator and the target named 'window' must both ensure tightness between the accelerator and the target and maintain a differential pressure while being as thin as possible to avoid a too great dissipation of the incident beam. In this respect, the interface is made of Inconel of low thickness in order to be as transparent as possible of the proton beam whose average power density is about of 10 μA.cm -2 , and is cooled by forced convection water of the target. An analysis of nominal and incidental situations of the facility operating mode has been conducted, especially in order to evaluate the consequences of abrupt and frequent shutdown or tripping of the accelerator on the thermomechanical behaviour of the spallation rods and the window, as well as in terms of thermal fatigue. (author)

  1. Thermal phenomenae in nuclear fuel rods

    International Nuclear Information System (INIS)

    Baigorria, Carlos.

    1983-12-01

    Thermal phenomenae occurring in a nuclear fuel rod under irradiation are studied. The most important parameters of either steady or transient thermal states are determined. The validity of applying the Fourier's approximation equations to these problems is also studied. A computer program TRANS is developed in order to study the transient cases. This program solves a system of coupled, non-linear partial differential equations, of parabolic type, in cylindrical coordinates with various boundary conditions. The benchmarking of the TRANS program is done by comparing its predictions with the analytical solution of some simplified transient cases. Complex transient cases such as those corresponding to characteristic reactor accidents are studied, in particular for typical pressurized heavy water reactor (PHWR) fuel rods, such as those of Atucha I. The Stefan problem emerging in the case of melting of the fuel element is solved. Qualitative differences between the classical Stefan problem, without inner sources, and that one, which includes sources are discussed. The MSA program, for solving the Stefan problem with inner sources is presented; and furthermore, it serves to predict thermal evolution, when the fuel element melts. Finally a model for fuel phase change under irradiation is developed. The model is based on the dimensional invariants of the percolation theory when applied to the connectivity of liquid spires nucleated around each fission fragment track. Suggestions for future research into the subject are also presented. (autor) [es

  2. Heterologous expression of hydrophobins RodA and RodB from Aspergillus fumigatus in host Pichia pastoris

    DEFF Research Database (Denmark)

    Pedersen, Mona Højgaard; Borodina, Irina; Frisvad, Jens Christian

    Introduction: Hydrophobins are small amphipatic proteins present on the spore surface of filamentous fungi. They most likely play an important role in the attachment of spores to a solid phase. The pathogenic fungus Aspergillus fumigatus expresses the hydrophobins RodA and RodB on the surface...... of its conidia and these may be of importance to the pathogenesis of the fungus. Although heterologous expression of hydrophobins has proven to be a challenge by past investigators, we made it the aim of this project to produce pure hydrophobins in sufficient quantities for further characterication...... and transformants were selected by zeocin resistance. The presence of the RodA and RodB genes in the transformants was confirmed by colony PCR. The expression of RodA and RodB genes was induced by growing cells in culture flasks for three days in buffered complex methanol medium as protein production was dependent...

  3. Experimental determination of temperature fields in sodium-cooled rod bundles with hexagonal rod arrangement and grid spacers

    International Nuclear Information System (INIS)

    Moeller, R.; Tschoeke, H.; Kolodziej, M.

    1977-01-01

    Three-dimensional temperature fields in the claddings of sodium cooled rods were determined experimentally under representative nominal operating conditions for a SNR typical 19-rod bundle model provided with spark-eroded spacers. These experiments are required to verify thermohydraulic computer programs which will provide the output data for strength calculations of the high loaded cladding tubes. In this work the essentials are reported of the measured circumferential distributions of wall temperatures of peripheral rods. In addition the sub-channel temperatures measured over the bundle cross section are indicated, they are required to sustain codes for the global thermohydraulic design of core elements. The most important results are: 1) The whole fuel element is located within the thermal entrance length. 2) High azimuthal temperature differences were measured in the claddings of peripheral rods, which are strongly influenced by the distance between the rod and the shroud, especially for the corner rod. 3) With decreasing Pe-number ( [de

  4. Rolls-Royce digital Rod Control System

    International Nuclear Information System (INIS)

    Pouillot, M.

    2010-01-01

    Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory costs: standardization of power modules and integration of control and monitoring on the same PC-card lead to a drastic reduction of spare part types, and simplification of the system. - Easy maintenance: - Replacement of a power module solves nearly all failures due to current control or monitoring for a coil. It is done instantly thanks to hot-plug capability. - On the front plate of power-modules, LEDs provide useful information for diagnostic: current setpoint from cycler, output current bar

  5. Grain Refinement and Mechanical Properties of Cu-Cr-Zr Alloys with Different Nano-Sized TiCp Addition.

    Science.gov (United States)

    Zhang, Dongdong; Bai, Fang; Wang, Yong; Wang, Jinguo; Wang, Wenquan

    2017-08-08

    The TiC p /Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiC p /Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiC p -reinforced Cu-Cr-Zr composites. Results show that nano-sized TiC p can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiC p . The grain size decreased from 82 to 28 μm with the nano-sized TiC p content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (σ UCS ) and yield strength (σ 0.2 ) of 4 wt% TiC p -reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiC p -reinforced Cu-Cr-Zr composites decreased with the increasing TiC p content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.

  6. Biomechanics of lumbar cortical screw-rod fixation versus pedicle screw-rod fixation with and without interbody support.

    Science.gov (United States)

    Perez-Orribo, Luis; Kalb, Samuel; Reyes, Phillip M; Chang, Steve W; Crawford, Neil R

    2013-04-15

    Seven different combinations of posterior screw fixation, with or without interbody support, were compared in vitro using nondestructive flexibility tests. To study the biomechanical behavior of a new cortical screw (CS) fixation construct relative to the traditional pedicle screw (PS) construct. The CS is an alternative to the PS for posterior fixation of the lumbar spine. The CS trajectory is more sagittally and cranially oriented than the PS, being anchored in the pars interarticularis. Like PS fixation, CS fixation uses interconnecting rods fastened with top-locking connectors. Stability after bilateral CS fixation was compared with stability after bilateral PS fixation in the setting of intact disc and with direct lateral interbody fixation (DLIF) or transforaminal lateral interbody fixation (TLIF) support. Standard nondestructive flexibility tests were performed in cadaveric lumbar specimens, allowing non-paired comparisons of specific conditions from 28 specimens (4 groups of 7) within a larger experiment of multiple hardware configurations. Condition tested and group from which results originated were as follows: (1) intact (all groups); (2) with L3-L4 bilateral PS-rods (group 1); (3) with bilateral CS-rods (group 2); (4) with DLIF (group 3); (5) with DLIF + CS-rods (group 4); (6) with DLIF + PS-rods (group 3); (7) with TLIF + CS-rods (group 2), and (8) with TLIF + PS-rods (group 2). To assess spinal stability, the mean range of motion, lax zone, and stiff zone at L3-L4 were compared during flexion-extension, lateral bending, and axial rotation. With intact disc, stability was equivalent after PS-rod and CS-rod fixation, except that PS-rod fixation was stiffer during axial rotation. With DLIF support, there was no significant difference in stability between PS-rod and CS-rod fixation. With TLIF support, PS-rod fixation was stiffer than CS-rod fixation during lateral bending. Bilateral CS-rod fixation provided about the same stability in cadaveric specimens

  7. Measurements of Burnout Conditions for Flow of Boiling Water in Vertical 3-Rod and 7-Rod Clusters

    International Nuclear Information System (INIS)

    Becker, Kurt M.; Hernborg, G.; Flinta, J.E.

    1964-08-01

    The present report deals with measurements of burnout conditions for flow of boiling water in vertical 3-rod and 7-rod clusters. Data were obtained,in respect of heating the rods only, as well as for simultaneous uniform and non-uniform heating of the rods and the shroud. Totally, 520 runs were performed. In the case of equal heat fluxes on all surfaces of the channels, burnout always occurred on the rods, and the data were low by a factor of about 1.3 compared with round duct data. When only the rods were heated, the data showed very low burnout values in comparison with the results for total uniform heating and round ducts. This disagreement was explained by considering the climbing film flow model and the fact that only a fraction of the channel perimeter was heated. For simultaneous and non-uniform heating of the rods and the shroud it was found that the shroud could be overloaded up to 50 per cent without reducing the margin of safety in respect of burnout for the rod cluster. Finally, a correlation for predicting burnout conditions in round ducts, annuli and rod clusters has been presented. This correlation predicts the burnout heat fluxes for the present measurements and previously obtained annuli measurements within ± 5 per cent

  8. Electrical properties of nanosized non-barrier inhomogeneities in Zn-based metal-semiconductor contacts to InP

    DEFF Research Database (Denmark)

    Clausen, Thomas; Leistiko, Otto

    1998-01-01

    We have found that the electrical properties of carriers across the metal-semiconductor interface for alloyed Zn based metallizations to n- and p-InP are dominated by nanosized non-barrier inhomogeneities. The effective area covered by the nanosized regions is a small fraction of the contact area...... resulting in high values of the specific contact resistance to p-InP. For n(-)-InP, thermionic emission across nanosized inhomogeneities dominates the carrier flow when T-ann > 440 degrees C. (C) 1998 Elsevier Science B.V....

  9. Rectifying Behavior of Aligned ZnO Nano rods on Mg0.3Zn0.7O Thin Film Template

    International Nuclear Information System (INIS)

    Salina Muhamad; Suriani Abu Bakar; Mohamad Hafiz Mamat; Rafidah Ahmad; Mohamad Rusop

    2011-01-01

    Rectifying behavior more than 3 orders of aligned zinc oxide (ZnO) nano rods grown on Mg 0.3 Zn 0.7 O thin film template using chemical bath deposition method was observed, giving a barrier height of 0.75 eV, and the ideality factor achieved was almost 6, which was analyzed using thermionic emission theory. Field emission scanning electron microscope (FESEM) images revealed that the grown ZnO was in hexagonal shape, uniformly distributed and in vertically aligned form. The crystallinity of the sample being studied using X-ray diffraction (XRD), where the highest peak was found at (002) phase, confirming that high crystallinity of ZnO was attained. The effect of metal/semiconductor junction between metal and aligned ZnO nano rods was discussed in further details. (author)

  10. Use of Supplemental Short Pre-Contoured Accessory Rods and Cobalt Chrome Alloy Posterior Rods Reduces Primary Rod Strain and Range of Motion Across the Pedicle Subtraction Osteotomy Level

    DEFF Research Database (Denmark)

    Hallager, Dennis Winge; Gehrchen, Poul Martin; Dahl, Benny

    2016-01-01

    STUDY DESIGN: In vitro cadaveric biomechanical study. OBJECTIVE: To assess effects of 4-rod reconstruction, rod material, and anterior column support on motion and surface rod strain in a pedicle subtraction osteotomy model. SUMMARY OF BACKGROUND DATA: Pedicle subtraction osteotomy (PSO) can...... correct significant sagittal deformity of the lumbar spine; however, revision rates are high. To reduce rod strain and the incidence of rod fracture, clinical use of multi-rod construction, cobalt chrome (CoCr) alloy rods, and interbody spacers adjacent to PSO has been proposed. Investigating both motion...

  11. Control device for the withdrawal of control rod

    International Nuclear Information System (INIS)

    Ando, Masaki.

    1985-01-01

    Purpose: To significantly suppress the maximum value of the control-rod worth upon control rod withdrawal. Constitution: At first, a signal for designating the first class is sent from a class-control section to the group-control section. In the group-control section, the peripheral group among the first class is designated by which the withdrawal of the control rods other than the peripheral group is inhibited and the control-rods in the peripheral group are withdrawn one by one. When all of them have been withdrawn, the group-control section designates the central group of the first class. All the control rods of the central group have been withdrawn, then the group-control section designates the peripheral group of the second class. Thereafter, the central group in the second class is designated. The control rods are thus withdrawn in the same manner hereinafter. The maximum value for the control-rod worth can be decreased by such a withdrawing sequence for the control rods. (Horiuchi, T.)

  12. Optimized Control Rods of the BR2 Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kalcheva, Silva; Koonen, E.

    2007-09-15

    At the present time the BR-2 reactor uses control elements with cadmium as neutron absorbing part. The lower section of the control element is a beryllium assembly cooled by light water. Due to the burn up of the lower end of the cadmium section during the reactor operation, the presently used rods for reactivity control of the BR-2 reactor have to be replaced by new ones. Considered are various types Control Rods with full active part of the following materials: cadmium (Cd), hafnium (Hf), europium oxide (Eu2O3) and gadolinium (Gd2O3). Options to decrease the burn up of the control rod material in the hot spot, such as use of stainless steel in the lower active part of the Control Rod are discussed. Comparison with the characteristics of the presently used Control Rods types is performed. The changing of the characteristics of different types Control Rods and the perturbation effects on the reactor neutronics during the BR-2 fuel cycle are investigated. The burn up of the Control Rod absorbing material, total and differential control rods worth, macroscopic and effective microscopic absorption cross sections, fuel and reactivity evolution are evaluated during approximately 30 operating cycles.

  13. Optimized Control Rods of the BR2 Reactor

    International Nuclear Information System (INIS)

    Kalcheva, Silva; Koonen, E.

    2007-01-01

    At the present time the BR-2 reactor uses control elements with cadmium as neutron absorbing part. The lower section of the control element is a beryllium assembly cooled by light water. Due to the burn up of the lower end of the cadmium section during the reactor operation, the presently used rods for reactivity control of the BR-2 reactor have to be replaced by new ones. Considered are various types Control Rods with full active part of the following materials: cadmium (Cd), hafnium (Hf), europium oxide (Eu2O3) and gadolinium (Gd2O3). Options to decrease the burn up of the control rod material in the hot spot, such as use of stainless steel in the lower active part of the Control Rod are discussed. Comparison with the characteristics of the presently used Control Rods types is performed. The changing of the characteristics of different types Control Rods and the perturbation effects on the reactor neutronics during the BR-2 fuel cycle are investigated. The burn up of the Control Rod absorbing material, total and differential control rods worth, macroscopic and effective microscopic absorption cross sections, fuel and reactivity evolution are evaluated during approximately 30 operating cycles.

  14. Control rod studies in small and medium sized fast reactors

    International Nuclear Information System (INIS)

    John, T.M.; Mohanakrishnan, P.; Mahalakshmi, B.; Singh, R.S.

    1988-01-01

    Control rods are the primary safety mechanism in the operation of fast reactors. Neutronic parameters associated with the control rods have to be evaluated precisely for studying the behaviour of the reactor under various operating conditions. Control rods are strong neutron absorbers discretely distributed in the reactor core. Accurate estimation of control rod parameters demand, in principle transport theory solutions in exact geometry. But computer codes for such evaluations usually consume exorbitantly large computer time and memory for even a single parameter evaluation. During the design of reactors, evaluation of these parameters will be required for many configurations of control rods. In this paper, the method used at Indira Gandhi Centre for Atomic Research for estimating the parameters associated with control rods is presented. Diffusion theory solutions were used for computations. A scheme using three dimensional geometry represented by triangular meshes and diffusion theory solutions in few energy groups for control rod parameter evaluation is presented. This scheme was employed in estimating the control rod parameters in a 500 Mw(e) fast reactor. Error due to group collapsing is estimated by comparing with 25 group calculations in three dimensions for typical cases. (author). 5 refs, 4 figs, 3 tabs

  15. Simple measuring rod method for the coaxiality of serial holes

    Science.gov (United States)

    Wang, Lei; Yang, Tongyu; Wang, Zhong; Ji, Yuchen; Liu, Changjie; Fu, Luhua

    2017-11-01

    Aiming at the rapid coaxiality measurement of serial hole part with a small diameter, a coaxiality measuring rod for each layer hole with a single LDS (laser displacement sensor) is proposed. This method does not require the rotation angle information of the rod, and the coaxiality of serial holes can be calculated from the measured values of LDSs after randomly rotating the measuring rod several times. With the mathematical model of the coaxiality measuring rod, each factor affecting the accuracy of coaxiality measurement is analyzed by simulation, and the installation accuracy requirements of the measuring rod and LDSs are presented. In the tolerance of a certain installation error of the measuring rod, the relative center of the hole is calculated by setting the over-determined nonlinear equations of the fitting circles of the multi-layer holes. In experiment, coaxiality measurement accuracy is realized by a 16 μm precision LDS, and the validity of the measurement method is verified. The manufacture and measurement requirements of the coaxiality measuring rod are low, by changing the position of LDSs in the measuring rod, the serial holes with different sizes and numbers can be measured. The rapid coaxiality measurement of parts can be easily implemented in industrial sites.

  16. Numerical investigation of flow past a row of rectangular rods

    Directory of Open Access Journals (Sweden)

    S.Ul. Islam

    2016-09-01

    Full Text Available A numerical study of uniform flow past a row of rectangular rods with aspect ratio defined as R = width/height = 0.5 is performed using the Lattice Boltzmann method. For this study the Reynolds number (Re is fixed at 150, while spacings between the rods (g are taken in the range from 1 to 6. Depending on g, the flow is classified into four patterns: flip-flopping, nearly unsteady-inphase, modulated inphase-antiphase non-synchronized and synchronized. Sudden jumps in physical parameters were observed, attaining either maximum or minimum values, with the change in flow patterns. The mean drag coefficient (Cdmean of middle rod is higher than the second and fourth rod for flip-flopping pattern while in case of nearly unsteady-inphase the middle rod attains minimum drag coefficient. It is also found that the Strouhal number (St of first, second and fifth rod decreases as g increases while that of other two have mixed trend. The results further show that there exist secondary interaction frequencies together with primary vortex shedding frequency due to jet in the gap between rods for 1 ⩽ g ⩽ 3. For the average values of Cdmean and St, an empirical relation is also given as a function of gap spacing. This relation shows that the average values of Cdmean and St approach to those of single rectangular rod with increment in g.

  17. Conceptual design report of the SMART fuel rod

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Ho; Lee, Chan Bock; Bang, Je Gun; Jung, Yeon Ho [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-03-01

    The SMART fuel rod is based on 17 x 17 KOFA(Korea Fuel Assembly) fuel rod of the 950MWe pressurize water reactor. The fuel stack length of the KOFA is 3658mm, otherwise SMART fuel rod stack length is 2000mm. The fuel rod contains UO{sub 2} pellets with the enrichment of 4.95%. All the fuel in core will be replaced every 35 months. The average LHGR of the fuel rod is 120 W/cm, commercial PWR is 178 W/cm, SMART LHGR is lower about 31% than commercial PWR. The core inlet and outlet temperature of coolant are respectively 270 deg C and 310 deg C, commercial PWR are respectively 291.6 deg C and 326.8 deg C, SMART inlet and outlet temperature is lower averaged 19.2 deg C than commercial PWR. The coolant use mixed soluble ammonia in high purity water and boron is not in. The general performance of the fuel rod UO{sub 2} pellet has been already verified through the sufficient burnup (60,000 MWd/MTU-rod avg.) experience as the rods of same design in commercial PWR's. But cladding corrosion is required the further verification. (author). 13 refs., 3 figs., 8 tabs.

  18. Evaluation of fuel rods behavior - under irradiation test

    International Nuclear Information System (INIS)

    Lameiras, F.S.; Terra, J.L.; Pinto, L.C.M.; Dias, M.S.; Pinheiro, R.B.

    1981-04-01

    By the accompanying of the irradiation of instrumented test fuel rods simulating the operational conditions in reactors, plus the results of post - irradiation exams, tests, evaluation and calibration of analitic modelling of such fuel rods is done. (E.G.) [pt

  19. Thermal-recovery of modal instability in rod fiber amplifiers

    DEFF Research Database (Denmark)

    Jørgensen, Mette Marie; Laurila, Marko; Noordegraaf, Danny

    2013-01-01

    We investigate the temporal dynamics of Modal instabilities (MI) in ROD fiber amplifiers using a 100 μm core rod fiber in a single-pass amplifier configuration, and we achieve ~200W of extracted output power before the onset of MI. Above the MI threshold, we investigate the temporal dynamics...

  20. The development and validation of control rod calculation methods

    International Nuclear Information System (INIS)

    Rowlands, J.L.; Sweet, D.W.; Franklin, B.M.

    1979-01-01

    Fission rate distributions have been measured in the zero power critical facility, ZEBRA, for a series of eight different arrays of boron carbide control rods. Diffusion theory calculations have been compared with these measurements. The normalised fission rates differ by up to about 30% in some regions, between the different arrays, and these differences are well predicted by the calculations. A development has been made to a method used to produce homogenised cross sections for lattice regions containing control rods. Calculations show that the method also reproduces the reaction rate within the rod and the fission rate dip at the surface of the rod in satisfactory agreement with the more accurate calculations which represent the fine structure of the rod. A comparison between diffusion theory and transport theory calculations of control rod reactivity worths in the CDFR shows that for the standard design method the finite mesh approximation and the difference between diffusion theory and transport theory (the transport correction) tend to cancel and result in corrections to be applied to the standard mesh diffusion theory calculations of about +- 2% or less. This result applies for mesh centred finite difference diffusion theory codes and for the arrays of natural boron carbide control rods for which the calculations were made. Improvements have also been made to the effective diffusion coefficients used in diffusion theory calculations for control rod followers and these give satisfactory agreement with transport theory calculations. (U.K.)

  1. Optimal control rod programs in power reactors

    International Nuclear Information System (INIS)

    Fadilah, S.M.; Lewins, J.

    1975-01-01

    Control rod programming is investigated with respect to optimising the power peaking factor and hence the utilisation of a nuclear reactor. A simplified diffusion model, initially with a finite number of regions, in cylindrical geometry, is used to enable optimal trajectories to be completely synthesised. The average discharge burnup problem is posed both as an external and as an internal optimisation. The connection between optimum power shape and the maximisation of the average discharge burnup is explored in a wider context. It is shown that optimum trajectories combine an initial singular solution of the Haling type with a terminal bang-bang solution. An extension to a higher number of regions and, on passing to the limit, to a diffusion model, provides an alternative proof of Haling's principle without the restriction to monotonic reactivity decrease with burnup. Numerical results in the two-region model are given to show the general scope of optimisation available. (author)

  2. Welding nuclear reactor fuel rod end plugs

    International Nuclear Information System (INIS)

    Yeo, D.

    1984-01-01

    Apparatus for applying a vacuum to a nuclear fuel rod cladding tube's interior through its open end while girth welding an inserted end plug to its other end. An airtight housing has an orifice with a seal which can hermetically engage the tube's open end. A vacuum hose has one end connected to the housing and the other end connected to a vacuum pump. A mechanized device moves the housing to engage or disengage its seal with the tube's open end. Preferably the mechanized device includes an arm having one end attached to the housing and the other end pivotally attached to a moveable table; an arm rotating device to coaxially align the housing's orifice with the welding-positioned tube; and a table moving device to engage the seal of the coaxially aligned orifice with the tube's open end

  3. Welding nuclear reactor fuel rod end plugs

    International Nuclear Information System (INIS)

    Yeo, D.

    1984-01-01

    Apparatus for applying a vacuum to a nuclear fuel rod cladding tube's interior through its open end while girth welding an inserted end plug to its other end. An airtight housing has an orifice with a seal which can hermetically engage the tube's open end. A vacuum hose has one end connected to the housing and the other end connected to a vacuum pump. A mechanized device which moves the housing to engage or disengage its seal with the tube's open end includes at least one arm having one end attached to the housing and the other end pivotally attached to a movable table; an arm rotating device to coaxially align the housing's orifice with the welding-positioned tube; and a table moving device to engage the seal of the coaxially aligned orifice with the tube's open end. (author)

  4. Control rod homogenization in heterogeneous sodium-cooled fast reactors

    International Nuclear Information System (INIS)

    Andersson, Mikael

    2016-01-01

    The sodium-cooled fast reactor is one of the candidates for a sustainable nuclear reactor system. In particular, the French ASTRID project employs an axially heterogeneous design, proposed in the so-called CFV (low sodium effect) core, to enhance the inherent safety features of the reactor. This thesis focuses on the accurate modeling of the control rods, through the homogenization method. The control rods in a sodium-cooled fast reactor are used for reactivity compensation during the cycle, power shaping, and to shutdown the reactor. In previous control rod homogenization procedures, only a radial description of the geometry was implemented, hence the axially heterogeneous features of the CFV core could not be taken into account. This thesis investigates the different axial variations the control rod experiences in a CFV core, to determine the impact that these axial environments have on the control rod modeling. The methodology used in this work is based on previous homogenization procedures, the so-called equivalence procedure. The procedure was newly implemented in the PARIS code system in order to be able to use 3D geometries, and thereby be take axial effects into account. The thesis is divided into three parts. The first part investigates the impact of different neutron spectra on the homogeneous control-rod cross sections. The second part investigates the cases where the traditional radial control-rod homogenization procedure is no longer applicable in the CFV core, which was found to be 5-10 cm away from any material interface. In the third part, based on the results from the second part, a 3D model of the control rod is used to calculate homogenized control-rod cross sections. In a full core model, a study is made to investigate the impact these axial effects have on control rod-related core parameters, such as the control rod worth, the capture rates in the control rod, and the power in the adjacent fuel assemblies. All results were compared to a Monte

  5. Damage development in rod-on-rod impact test on 1100 pure aluminum

    Science.gov (United States)

    Iannitti, G.; Bonora, N.; Bourne, N.; Ruggiero, A.; Testa, G.

    2017-01-01

    Stress triaxiality plays a major role in the nucleation and growth of ductile damage in metals and alloys. Although, the mechanisms responsible for ductile failure are the same at low and high strain rate, in impact dynamics, in addition to time resolved stress triaxiality and plastic strain accumulation, pressure also contributes to establish the condition for ductile failure to occur. In this work, ductile damage development in 1100 commercially pure aluminum was investigated by means of rod-on-rod (ROR) impact tests. Based on numerical simulations, using a continuum damage mechanics (CDM) model that accounts for the role of pressure on damage parameters and stochastic variability of such parameters, the impact velocity for no damage, incipient and fully developed damage were estimated. ROR tests at selected velocities were performed and damage distribution and extent were investigated by sectioning of soft recovered samples. Comparison between numerical simulations and experimental results is presented and discussed.

  6. Simulation of fuel rod irradiation capsules in water loops by electric heater rods

    International Nuclear Information System (INIS)

    Lopez, J.; Montes, M.; Serrano, J.; Haefner, H.E.

    1984-01-01

    The out of pile simulation of irradiation devices was carried out by J.E.N. in the frame of the KfK-JEN joint experiment for irradiation of fast reactor fuel rods (IVO-FR2-Vg7). A typical single-wall-Nak (22% Na, 78% K) electrical heated capsule was fabricated and hydraulical tests were done. The capsule was instrumented with 10 thermocouples in order to obtain the radial temperature profile into the capsule in function of the electrical rod power (max. 215 w/cm), flow rate (max. 2,4 m 3 /h) and coolant temperature (max. 60degC). The experimental values are compared to the Tecap-Code results. (author)

  7. Stress Analysis of Fuel Rod under Axial Coolant Flow

    International Nuclear Information System (INIS)

    Jin, Hai Lan; Lee, Young Shin; Lee, Hyun Seung; Park, Num Kyu; Jeon, Kyung Rok

    2010-01-01

    A pressurized water reactor(PWR) fuel assembly, is a typical bundle structure, which uses light water as a coolant in most commercial nuclear power plants. Fuel rods that have a very slender and long clad are supported by fuel assembly which consists of several spacer grids. A coolant is a fluid which flows through device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. But at the same time, the coolant flow will bring out the fluid induced vibration(FIV) of fuel rods and even damaged the fuel rod. This study has been conducted to investigate the flow characteristics and nuclear reactor fuel rod stress under effect of coolant. Fluid structure interaction(FSI) analysis on nuclear reactor fuel rod was performed. Fluid analysis of the coolant which flow along the axial direction and structural analysis under effect of flow velocity were carried out under different output flow velocity conditions

  8. Interfacial colloidal rod dynamics: Coefficients, simulations, and analysis

    Science.gov (United States)

    Yang, Yuguang; Bevan, Michael A.

    2017-08-01

    Colloidal rod diffusion near a wall is modeled and simulated based on a constrained Stokesian dynamic model of chains-of-spheres. By modeling colloidal rods as chains-of-spheres, complete diffusion tensors are computed for colloidal rods in bulk media and near interfaces, including hydrodynamic interactions, translation-rotation coupling, and all diffusion modes in the particle and lab frames. Simulated trajectories based on the chain-of-spheres diffusion tensor are quantified in terms of typical experimental quantities such as mean squared positional and angular displacements as well as autocorrelation functions. Theoretical expressions are reported to predict measured average diffusivities as well as the crossover from short-time anisotropic translational diffusion along the rod's major axis to isotropic diffusion. Diffusion modes are quantified in terms of closed form empirical fits to model results to aid their use in interpretation and prediction of experiments involving colloidal rod diffusion in interfacial and confined systems.

  9. A review of control rod calibration methods for irradiated AGRs

    International Nuclear Information System (INIS)

    Telford, A.R.R.

    1975-10-01

    Methods of calibrating control rods with particular reference to irradiated CAGR are surveyed. Some systematic spatial effects are found and an estimate of their magnitude made. It is concluded that control rod oscillation provides a promising method of calibrating rods at power which is as yet untried on CAGR. Also the rod drop using inverse kinetics provides a rod calibration but spatial effects may be large and these would be difficult to correct theoretically. The pulsed neutron technique provides a calibration route with small errors due to spatial effects provided a suitable K-tube can be developed. The xenon transient method is shown to have statial effects which have not needed consideration in earlier reactors but which in CAGR would need very careful evaluation. (author)

  10. Substitute safety rods: Physics design and NTG calibration

    International Nuclear Information System (INIS)

    Baumann, N.P.

    1991-07-01

    Under certain assumed accident conditions, an SRS reactor may loose most of its bulk moderator while maintaining flow to fuel assemblies. If this occurs immediately after operation at power, components normally dependent on convective heat transfer to the moderator will heat up with the possibility of melting that component. One component at risk is the safety rod. Tests have shown that the current cadmium safety rod, which contains aluminum as well as cadmium, can fail at temperatures only slightly in excess of 500 deg C. Computations indicate that such temperatures can be reached with operating powers well below the 50% power limit now imposed by other accident scenarios. Safety rod melting would thus establish a new lower operating limit. A substitute safety rod that could tolerate much higher temperatures would eliminate this limit. This memorandum details the physics characteristics of a suitable replacement rod. 7 refs

  11. TileCal ROD Motherboard Software Library User's Manual

    CERN Document Server

    Salvachúa, B; Castillo, C; Cuenca, C; Ferrer, A; Fullana, E; Higón, E; Iglesias, C; Munar, A; Poveda, J; Ruiz-Martinez, A; Solans, C; Valls, J

    2005-01-01

    This note describes the software library and an associated standalone application program to handle the TileCal ROD VME motherboard. The library uses the CMT packages vme_rcc and rcc_error, from the ATLAS Online Data Flow to handle the standard crate controller, VP-110 from Concurrent Technologies, and the custom bit3_rcc CMT package to handle an alternative crate controller, the BIT-3 from SBSTM Technologies. The ROD library defines several C++ classes which can be used in either standalone applications to control and debug the RODs or with the TDAQ online software integration of the back-end hardware for the TileCal detector. The library also includes special auxiliary classes to handle additional back-end boards related to the ROD operation like the TBM or the ROD injectors.

  12. Buckling of a thin rod under cylindrical constraint

    Science.gov (United States)

    Miller, Jay; Su, Tianxiang; Wicks, Nathan; Pabon, Jahir; Bertoldi, Katia; Reis, Pedro

    2013-03-01

    We investigate the buckling and post-buckling behavior of a thin elastic rod, under cylindrical constraint, with distributed loading. Our precision model experiments consist of injecting a custom-fabricated rod into a transparent glass pipe. Under imposed velocity (leading to frictional axial loading), a portion of the initially straight rod first buckles into a sinusoidal mode and eventually undergoes a secondary instability into a helical configuration. The buckling and post-buckling behavior is found to be highly dependent on the system's geometry, namely the injected rod length and the aspect ratio of the rod to pipe diameter, as well as material parameters. We quantify the critical loads for this sequence of instabilities, contrast our results with numerical experiments and rationalize the observed behavior through scaling arguments.

  13. Low temperature solvothermal synthesis of nanosized NiSb as a Li-ion battery anode material

    International Nuclear Information System (INIS)

    Xie, J.; Zhao, X.B.; Yu, H.M.; Qi, H.; Cao, G.S.; Tu, J.P.

    2007-01-01

    Nanosized intermetallic compound NiSb was successfully synthesized by a solvothermal route and studied as a promising anode material for secondary lithium-ion batteries. The as-prepared NiSb powder was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM). The electrochemical performance of the nanosized NiSb electrode was investigated by constant current charge and discharge cycling and electrochemical impedance spectroscopy (EIS). It was found that the nanosized NiSb shows a higher initial capacity compared to microsized one prepared by a levitation-melting/ball-milling route due to larger specific surface area of the nanomaterial. The nanosized NiSb shows a rapid capacity fade due to the pulverization and exfoliation of active material caused by severe electrochemical grinding upon long-term cycling

  14. Device for replacing the rods of a fuel element of a nuclear reactor

    International Nuclear Information System (INIS)

    Nissel, B.; Kybranz, R.; Will, R.

    1977-01-01

    In order to be able to replace several separate rods (fuel rods or absorber rods), in a fuel element, a special grab is introduced, which consists of several individual gripping devices and is operated by spring loading. (TK) [de

  15. Hydrothermally formed three-dimensional hexagon-like P doped Ni(OH)2 rod arrays for high performance all-solid-state asymmetric supercapacitors

    Science.gov (United States)

    Li, Kunzhen; Li, Shikuo; Huang, Fangzhi; Lu, Yan; Wang, Lei; Chen, Hong; Zhang, Hui

    2018-01-01

    Three dimensional hexagon-like phosphrous (P) doped Ni(OH)2 rod arrays grown on Ni foam (NF) are fabricated by a facile and green one-step hydrothermal process. Ni foam is only reacted in a certain concentration of P containing H2O2 aqueous solution. The possible growth mechanism of the P doped Ni(OH)2 rod arrays is discussed. As a battery-type electrode material in situ formed on Ni foam, the binder-free P doped Ni(OH)2 rod arrays electrode displays a ultrahigh specific areal capacitance of 2.11C cm-2 (3.51 F cm-2) at 2 mA cm-2, and excellent cycling stability (95.5% capacitance retention after 7500 cycles). The assembled all-solid-state asymmetric supercapacitor (AAS) based on such P doped Ni(OH)2 rod arrays as the positive electrode and activated carbon as the negative electrode achieves an energy density of 81.3 Wh kg-1 at the power density of 635 W kg-1. The AAS device also exhibits excellent practical performance, which can easily drive an electric fan (3 W rated power) when two AAS devices are assembled in series. Thus, our synthesized P doped Ni(OH)2 rod arrays has a lot of potential applications in future energy storage prospects.

  16. Optimization of fuel rod enrichment distribution to minimize rod power peaking throughout life within BWR fuel assembly

    International Nuclear Information System (INIS)

    Hirano, Yasushi; Hida, Kazuki; Sakurada, Koichi; Yamamoto, Munenari

    1997-01-01

    A practical method was developed for determining the optimum fuel enrichment distribution within a boiling water reactor fuel assembly. The method deals with two different optimization problems, i.e. a combinatorial optimization problem grouping fuel rods into a given number of rod groups with the same enrichment, and a problem determining an optimal enrichment for each fuel rod under the resultant rod-grouping pattern. In solving these problems, the primary goal is to minimize a predefined objective function over a given exposure period. The objective function used here is defined by a linear combination: C 1 X+C 2 X G , where X and X G stand for a control variable to give the constraint respectively for a local power peaking factor and a gadolinium rod power, and C 1 and C 2 are user-definable weighting factor to accommodate the design preference. The algorithm of solving the combinatorial optimization problem starts with finding the optimal enrichment vector without any rod-grouping, and promising candidates of rod-grouping patterns are found by exhaustive enumeration based on the resulting fuel enrichment ordering, and then the latter problem is solved by using the method of approximation programming. The practical application of the present method is shown for a contemporary 8x8 Pu mixed-oxide fuel assembly with 10 gadolinium-poisoned rods. (author)

  17. Great improvement on tetracycline removal using ZnO rod-activated carbon fiber composite prepared with a facile microwave method

    Energy Technology Data Exchange (ETDEWEB)

    Tran Thi, Viet Ha; Lee, Byeong-Kyu, E-mail: bklee@ulsan.ac.kr

    2017-02-15

    Highlights: • ZnO rod-ACF was prepared by a method involving a microwave within only 3 min. • ZnO rods (average diameter of 0.3–0.5 μm, length of 1.0–1.5 μm) were grown on ACF. • 99% of tetracycline was degraded and 90.7% TOC was removed within 1 h under UV light. • ZnO rod-ACF achieved high performances even after three cycles of uses. - Abstract: New composite materials of activated carbon fiber (ACF) coated with zinc oxide (ZnO) were obtained by applying a green, cost-effective and rapid synthetic route using a commercial microwave oven. ZnO rods with a uniform and stable structure and an average diameter of 0.3–0.5 μm and length of 1.0–1.5 μm were achieved after only 3-min microwave treatment. The properties of ZnO were efficiently transferred to ACF, such that the resulting material, termed ZnO rod-ACF, demonstrated a promising potential as an efficient photocatalyst and simultaneously as an adsorbent. Pharmaceutical tetracycline at a concentration of 40 mg/L was used to evaluate the organic pollutant removal capacity of the synthesized materials. At pH 8, ZnO rod-ACF exhibited excellent removal capacity (over 99%) and mineralization (90.7%) of tetracycline in aqueous solution within 1 h under UV irradiation. The stability of ZnO rod-ACF was maintained and the mineralization of tetracycline was also maintained at 81.35% after multiple usage cycles. The photodegradation pathways of tetracycline were proposed based on the identified reaction intermediates.

  18. Deposition of very thin uniform indium sulfide layers over metallic nano-rods by the Spray-Ion Layer Gas Reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Genduso, G. [Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Università di Palermo, Viale delle Scienze, 90100 Palermo (Italy); Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Inguanta, R.; Sunseri, C.; Piazza, S. [Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Università di Palermo, Viale delle Scienze, 90100 Palermo (Italy); Kelch, C.; Sáez-Araoz, R. [Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); Zykov, A. [Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); present address: Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15,12489 Berlin (Germany); Fischer, Ch.-H., E-mail: fischer@helmholtz-berlin.de [Institut for Heterogeneous Material Systems, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany); second affiliation: Free University Berlin, Chemistry Institute, Takustr. 3, D-14195 Berlin (Germany)

    2013-12-02

    Very thin and uniform layers of indium sulfide were deposited on nickel nano-rods using the sequential and cyclical Spray-ILGAR® (Ion Layer Gas Reaction) technique. Substrates were fabricated by electrodeposition of Ni within the pores of polycarbonate membranes and subsequent chemical dissolution of the template. With respect to the depositions on flat substrates, experimental conditions were modified and optimized for the present geometry. Our results show that nano-rods up to a length of 10 μm were covered uniformly along their full length and with an almost constant film growth rate, thus allowing a good control of the coating thickness; the effect of the deposition temperature was also investigated. However, for high numbers of process steps, i.e. thickness, the films became uneven and crusty, especially at higher temperature, mainly owing to the simultaneous side reaction of the metallic Ni forming nickel sulfide at the surface of the rods. However, such a problem occurs only in the case of reactive nano-rod materials, such as less noble metals. It could be strongly reduced by doubling the spray step duration and thereby sealing the metallic surface before the process step of the sulfurization. Thus, quite smooth, about 100 nm thick coatings could be obtained. - Highlights: • Ni nano-rod substrates were grown within polycarbonate membranes. • We can coat nano-rods uniformly by the Ion Layer Gas Reaction method. • As a model we deposited up to about 100 nm In{sub 2}S{sub 3} on Ni nanorods (250 nm × 10 μm). • Element mapping at insulated rods showed homogenous coating over the full length. • Parameter optimization reduced effectively the Ni sulfide formation.

  19. Novel detection system for biomolecules using nano-sized bacterial magnetic particles and magnetic force microscopy.

    Science.gov (United States)

    Amemiya, Yosuke; Tanaka, Tsuyoshi; Yoza, Brandon; Matsunaga, Tadashi

    2005-11-21

    A system for streptavidin detection using biotin conjugated to nano-sized bacterial magnetic particles (BMPs) has been developed. BMPs, isolated from magnetic bacteria, were used as magnetic markers for magnetic force microscopy (MFM) imaging. The magnetic signal was obtained from a single particle using MFM without application of an external magnetic field. The number of biotin conjugated BMPs (biotin-BMPs) bound to streptavidin immobilized on the glass slides increased with streptavidin concentrations up to 100 pg/ml. The minimum streptavidin detection limit using this technique is 1 pg/ml, which is 100 times more sensitive than a conventional fluorescent detection system. This is the first report using single domain nano-sized magnetic particles as magnetic markers for biosensing. This assay system can be used for immunoassay and DNA detection with high sensitivities.

  20. Synthesis of nano-sized zirconium carbide by a sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Dolle, M.; Gosset, D.; Simeone, D. [CEA Saclay, DMN, SRMA, Lab Anal Microstruct Mat, F-91191 Gif Sur Yvette (France); Bogicevic, C.; Karolak, F.; Baldinozzi, G. [Ecole Cent Paris, CNRS, UMR 8580, Lab Struct Proprietes and Modelisat Solides, F-92295 Chatenay Malabry (France)

    2007-07-01

    Nano-sized zirconium carbide was synthesized by a new simple sol-gel method Using zirconium n-prop-oxide, acetic acid as chemical modifier, and saccharose as carbon source. When heat-treated at 900 C under flowing argon, gels transformed into intimately mixed amorphous carbon and nano-sized tetragonal ZrO{sub 2}. Further heat treatments above 1200 degrees C led to the formation of zirconium carbide with some dissolved oxygen in the lattice. Oxygen content Could be reduced by increasing the heat treatment temperature from 1400 to 1600 degrees C, which unfortunately also induced a mean crystallites size increase from 90 to 150 inn. Short heat treatments above 1600 degrees C were carried out to further purify the samples and to limit the particles growth. A compromise between purity and average crystallite's size could then be found. Powders were assessed using X-ray diffraction, thermal analysis and scanning electron microscopy. (authors)

  1. NANO-SIZED PIGMENT APPLICATIONS IN İZNİK TILES

    Directory of Open Access Journals (Sweden)

    Esin GÜNAY

    2012-12-01

    Full Text Available Traditional İznik tiles are known as “unproducable” due to its high quartz content. İznik tiles contain four different layers as “body, engobe (slip, decors and glaze” and each one has some different starting materials. Recent studies have showed that the production techniques and the particle size of pigments are important parameters in development of colours. TUBITAK MRC and İznik Foundation carried out an experimental work to improve and understand the effects of nanotechnology application to İznik tiles. High quartz content was kept as it is and pigments were applied in decorationas nano-sized pigments.İznik tiles were produced and comparison was carried out between traditional and modern İznik tiles in colour and brightness. Characterization techniques were used in order to understand andcompare the results and also the effects of nano-sized pigments to İznik tiles.

  2. Study on the effect of fuel rod vibration characteristics on the grid-to-rod fretting wear

    International Nuclear Information System (INIS)

    Kyu Tae Kim

    1997-01-01

    The fretting wear-induced fuel rod failure may be caused by excessive flow-induced vibration and/or inadequate fuel rod support by spacer grid springs. In order to evaluate the fuel rod support conditions, the GRIDFORCE program has been developed. This program takes into account cladding creep rate, initial spring deflection, initial spring force, and spring force relaxation rate as the key fuel design parameters affecting the in-reactor fuel rod supporting conditions. On the other hand, relationship of fuel rod supporting conditions and flow-induced vibration characteristics has been derived, based on fretting wear damage patterns observed in some PWRs. Comparison of the predicted data of the GRIDFORCE program and the fretting wear damage patterns indicates that the GRIDFORCE program can be utilized as an effective tool in evaluating the fretting wear damage

  3. An alternative pathway for signal flow from rod photoreceptors to ganglion cells in mammalian retina.

    OpenAIRE

    DeVries, S H; Baylor, D A

    1995-01-01

    Rod signals in the mammalian retina are thought to reach ganglion cells over the circuit rod-->rod depolarizing bipolar cell-->AII amacrine cell-->cone bipolar cells-->ganglion cells. A possible alternative pathway involves gap junctions linking the rods and cones, the circuit being rod-->cone-->cone bipolar cells-->ganglion cells. It is not clear whether this second pathway indeed relays rod signals to ganglion cells. We studied signal flow in the isolated rabbit retina with a multielectrode...

  4. Study on the Influence of Nano-SiC on the Structure and Properties of Nodular Cast Iron

    Science.gov (United States)

    Zhu, Ruixiang; SU, Yong; Qin, Xinyu

    2017-10-01

    In this paper, the effect of adding Nano-SiC on the structure and mechanical properties of nodular cast iron during inoculation and spheroidizing process is mainly studied. Three sets of samples were set up: one group is without adding Nano-SiC, and the other two groups are adding Nano-SiC in the spheroidizing process and inoculation step. The three groups of castings were sampled from the core and 1/4 respectively and treated by isothermal quenching. The influences of Nano-SiC and heat treatment process on the microstructure and mechanical properties of nodular cast iron were discussed through the observation of impact work, hardness and metallographic structure of Vivtorinox. The experimental results show that with the addition of Nano-SiC, the spheroidization rate, spheroidization degree and graphitization of the graphite in casting structure are improved. In mechanical properties, the impact toughness of the samples with adding Nano-SiC during inoculation is the best, and the hardness of nodular cast iron can be improved. After heat treatment, the impact toughness of nodular cast iron samples increased obviously, but the hardness decreased generally.

  5. Mechanical properties of dental resin composites by co-filling diatomite and nanosized silica particles

    International Nuclear Information System (INIS)

    Wang Hua; Zhu Meifang; Li Yaogang; Zhang Qinghong; Wang Hongzhi

    2011-01-01

    The aim of this study was to investigate the mechanical property effects of co-filling dental resin composites with porous diatomite and nanosized silica particles (OX-50). The purification of raw diatomite by acid-leaching was conducted in a hot 5 M HCl solution at 80 deg. C for 12 h. Both diatomite and nanosized SiO 2 were silanized with 3-methacryloxypropyltrimethoxysilane. The silanized inorganic particles were mixed into a dimethacrylate resin. Purified diatomite was characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy and an N 2 adsorption-desorption isotherm. Silanized inorganic particles were characterized using Fourier transform infrared spectroscopy and a thermogravimetric analysis. The mechanical properties of the composites were tested by three-point bending, compression and Vicker's microhardness. Scanning electron microscopy was used to show the cross-section morphologies of the composites. Silanization of diatomite and nanosized silica positively reinforced interactions between the resin matrix and the inorganic particles. The mechanical properties of the resin composites gradually increased with the addition of modified diatomite (m-diatomite). The fracture surfaces of the composites exhibited large fracture steps with the addition of m-diatomite. However, when the mass fraction of m-diatomite was greater than 21 wt.% with respect to modified nanosized silica (mOX-50) and constituted 70% of the resin composite by weight, the mechanical properties of the resin composites started to decline. Thus, the porous structure of diatomite appears to be a crucial factor to improve mechanical properties of resin composites.

  6. Synthesis of Nanosize Yttria-Stabilized Zirconia by a Molecular Decomposition Process

    Science.gov (United States)

    Jiang, Yi; Bhide, Sanjeevani V.; Virkar, Anil V.

    2001-02-01

    Nanosize yttria-stabilized zirconia (YSZ) was synthesized by a novel approach based on molecular decomposition. In this approach, yttria-doped BaZrO3 (Y-BaZrO3) or yttria-doped Na2ZrO3 (Y-Na2ZrO3) precursors were first synthesized from BaCO3, ZrO2, and Y2O3 or BaCO3 and commercial YSZ for Y-BaZrO3, and from Na2CO3 and YSZ for Y-Na2ZrO3, by a conventional solid-state reaction method. The precursors were then boiled to leach away the unwanted species, BaO or Na2O, either in a dilute HNO3 solution in water in the case of Y-BaZrO3, or in deionized water in the case of Y-Na2ZrO3. During boiling in HNO3 or water, the residue of Zr-Y-O skeleton formed fine, nanosize YSZ particles. The particle size of the as-synthesized nanosize powders estimated from X-ray diffraction peak broadening was ∼2-3 nm, while that estimated from specific surface area measurements by BET adsorption isotherm was ∼15 nm. Examination under a transmission electron microscope showed that the crystallite size was ∼5 nm. Samples were also examined by Raman spectroscopy to determine the crystallographic polymorph of the YSZ formed. Subsequent heating in air led to particle growth. However, even when the particles were heated to a temperature as high as 1000°C, the particle size was well in the nanosize range.

  7. Synthesis and characterization of nanosized Cu/ZnO catalyst by polyol method.

    Science.gov (United States)

    Altinçekiç, Tuba Gürkaynak; Boz, Ismail; Aktürk, Selçuk

    2008-02-01

    Nanosized catalysts composed of metallic copper supported on zinc oxide have been synthesized by the polyol process. Average crystallite size of copper was between 10 and 45 nm. Cu/ZnO catalyst particles were characterized by various techniques, such as X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and dynamic light scattering analysis (DLS).

  8. Low temperature synthesis of nanosized Mn1–xZnxFe2O4 ferrites ...

    Indian Academy of Sciences (India)

    Nanosized Mn1–ZnFe2O4 ( = 0, 0.1, 0.3, 0.5, 0.6, 0.7, 0.9) mixed ferrite samples of particle size < 12 nm were prepared using the co-precipitation technique by doping the Zn2+ ion impurities. Autoclave was employed to maintain constant temperature of 80°C and a constant pressure. The X-ray analysis and the IR ...

  9. Anti-friction properties of thin layered nanosized protective films “Epilam”: synergy effect

    International Nuclear Information System (INIS)

    Vokhidov, A S

    2017-01-01

    In the general concept of temperature-resistant antifriction coatings, greate attention is paid to the growing use of multifunctional films. Epilams are polymer compositions, studying organic chemistry, namely to compositions (liquids), which, when applied to a solid surface, form on it nanosize multifunctional molecular film of a certain way of oriented molecules of surface-active agents (surfactants, SAA), which significantly changes the surface energy of the base (substrate). (paper)

  10. Anti-friction properties of thin layered nanosized protective films “Epilam”: synergy effect

    Science.gov (United States)

    Vokhidov, A. S.

    2017-05-01

    In the general concept of temperature-resistant antifriction coatings, greate attention is paid to the growing use of multifunctional films. Epilams are polymer compositions, studying organic chemistry, namely to compositions (liquids), which, when applied to a solid surface, form on it nanosize multifunctional molecular film of a certain way of oriented molecules of surface-active agents (surfactants, SAA), which significantly changes the surface energy of the base (substrate).

  11. Dynamic rod worth measurements (''Rod Insertion''). Final report for the period 01 December 1994 - 30 November 1996

    International Nuclear Information System (INIS)

    Bogdan, G.

    1996-12-01

    Reload startup physics tests are performed for pressurized water reactors (PWR power plant) following a refuelling or other significant core alteration for which nuclear design calculations are required. Part of the reload startup physics tests are control rod group worths measurements. for this purpose a new so-called method ''Rod-Insertion'' was developed. It can also be used as an additional measuring instrument on the research reactor for education purposes. The principle of the rod-insertion method is to start from a critical reactor operating at low power and to measure the time-dependent reactivity change while a control rod is inserted into the core. Unlike in the rod-drop method, the measured control rod is inserted with the drive mechanism at normal speed. By analyzing the flux trace using point-kinetics, not only the total rod worth but also the differential and the integral rod worth curves are obtained. A high-quality electrometer is required for monitoring the neutron flux. The analysis is performed by transferring the data to an IBM PC compatible with some additional standard electronic board and the associated software. The new reactivity meter has been validated on the TRIGA Mark II reactors in Ljubljana and Vienna and at the Krsko Nuclear Power Plant during physics startup tests after reload. The results proved the high performance of the reactivity meter in the standard applications according to the existing procedures, as well as in the new rod-insertion technique of measuring the control rod group worths. This method drastically differs from others such as absence of any chemical control of reactivity (like boron exchange method), and minimizing a testing time and waste coolant production

  12. Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Rahimi, Fahimeh; Aro, Eva-Mari; Lee, Choon-Hwan; Allakhverdiev, Suleyman I

    2012-10-07

    There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese-calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.

  13. Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Rahimi, Fahimeh; Aro, Eva-Mari; Lee, Choon-Hwan; Allakhverdiev, Suleyman I.

    2012-01-01

    There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups. PMID:22809849

  14. Binary mixing of micelles using Pluronics for a nano-sized drug delivery system.

    Science.gov (United States)

    Lee, Eun Seong; Oh, Young Taik; Youn, Yu Seok; Nam, Myounghwa; Park, Byungtae; Yun, Jungmin; Kim, Ji Hoon; Song, Ho-Taek; Oh, Kyung Taek

    2011-01-01

    Pluronics with different structural compositions and properties are used for several applications, including drug delivery systems. We developed a binary mixing system with two Pluronics, L121/P123, as a nano-sized drug delivery carrier. The lamellar-forming Pluronic L121 (0.1 wt%) was incorporated with Pluronic P123 to produce nano-sized dispersions (in case of 0.1 and 0.5 wt% P123) with high stability due to Pluronic P123 and high solubilization capacity due to Pluronic L121. The binary systems were spherical and less than 200-nm diameter, with high thermodynamic stability (at least 2 weeks) in aqueous solution. The CMC of the binary system was located in the middle of the CMC of each polymer. In particular, the solubilization capacity of the binary system (0.1/0.1 wt%) was higher than mono-systems of P123. The main advantage of binary systems is overcoming limitations of mono systems to allow tailored mixing of block copolymers with different physicochemical characteristics. These nano-sized systems may have potential as anticancer drug delivery systems with simple preparation method, high stability, and high loading capacity. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. One-pot synthesis of silanol-free nanosized MFI zeolite

    Science.gov (United States)

    Grand, Julien; Talapaneni, Siddulu Naidu; Vicente, Aurélie; Fernandez, Christian; Dib, Eddy; Aleksandrov, Hristiyan A.; Vayssilov, Georgi N.; Retoux, Richard; Boullay, Philippe; Gilson, Jean-Pierre; Valtchev, Valentin; Mintova, Svetlana

    2017-10-01

    The synthesis of nanostructured zeolites enables modification of catalytically relevant properties such as effective surface area and diffusion path length. Nanostructured zeolites may be synthesized either in alkaline media, and so contain significant numbers of hydrophilic silanol groups, or in expensive and harmful fluoride-containing media. Here, we report and characterize, using a combination of experimental and theoretical techniques, the one-pot synthesis of silanol-free nanosized MFI-type zeolites by introducing atomically dispersed tungsten; this prevents silanol group occurrence by forming flexible W-O-Si bridges. These W-O-Si bonds are more stable than Si-O-Si in the all-silica MFI zeolite. Tungsten incorporation in nanosized MFI crystals also modifies other properties such as structural features, hydrophobicity and Lewis acidity. The effect of these is illustrated on the catalytic epoxidation of styrene and separation of CO2 and NO2. Silanol-free nanosized W-MFI zeolites open new perspectives for catalytic and separation applications.

  16. An agar diffusion study comparing the antimicrobial activity of Nanoseal with some other endodontic sealers.

    Science.gov (United States)

    Aal-Saraj, Ali Burak; Ariffin, Zaihan; Masudi, Sam'an Malik

    2012-08-01

    The aim of this study was to evaluate the antimicrobial activity of a new experimental nano-hydroxyapatite epoxy resin-based sealer (Nanoseal) with several other commercially available sealers; AH26, Tubliseal, Sealapex and Roekoseal against Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcus sobrinus and Escherichia coli for up to 7 days. Agar diffusion was used in this study. Fifty Muller-Hinton agar plates were prepared and divided into five experimental groups (n = 10), for each micro-organism. Another 10 agar plates were used as positive and negative controls. Endodontic sealers were tested against each micro-organism. Inhibition zones produced were recorded. The results of this study showed that all test materials exhibited inhibition zones towards the tested micro-organisms for 7 days except for Roekoseal, which showed no inhibition zones. Nanoseal and AH26 exhibited similar zones of inhibition. Significant difference was found between Nanoseal and the other tested sealers (P < 0.001). © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

  17. Nano-Sized Fume Biogas Production from Food Waster Using Semi-Continuous Anaerobic Digester.

    Science.gov (United States)

    Park, Keum-Joo; Seo, Seong-Gyu; Kim, Eun-Sik; Islam, M N; Song, Hyung-Woon; Yoon, Hyung-Sun

    2018-02-01

    In this study, the nano-sized fume biogas production from food waste was investigated using lab scale semi-continuous stirred tank reactor (SCSTR) at 35 °C with 30d HRT and 30L working volume. The mesophilic digestion test was performed with three different feed materials (food waste) and food to microorganism (F/M) ratios (0.13, 0.34, and 0.27) in the same experiment. The results showed that the F/M ratios significantly affected the biogas production rate. The highest production rate was obtained at F/M ratio of 0.13. Nano-sized fume biogas produced in anaerobic digestion consists of 68.7% CH4, 31.2% CO2 and 30~200 nm particle. The average nano-sized fume biogas and methane production of digester were 29.96 L/Kg versus day-1 and 20.58 L/Kg versus day-1, respectively. The CH4 could be calculated as the heat energy 1.85 Kcal/Kg VS day-1. The digestion was operated without addition of chemicals or nutrients into the system.

  18. Impact loading of a BWR control rod during braking

    International Nuclear Information System (INIS)

    Heeschen, U.

    1977-01-01

    In an emergency case the control rods of a boiling water reactor are shot into the RPV from below against the weight of the rods with drive motors. According to the position of the control rods between the fuel elements the rods can reach in that case velocities up to 4 m/s. The moved masses of the control rods and of the pistons (both of them are connected by a coupling) are braked through a cup spring which transfers its forces to the RPV-bottom sphere. The spring has to be designed that in this case tthe complete kinetic energy of he control rods of about 1000Nm can be taken up. The spring power and the inertia of the moved masses cause extremely high loadings during and shortly after the impact onto the spring. The shock-like loading propagates along the whole rod at the speed of sound, and this is also the reason why the weaker cross-sections have to endure considerable short-term stress peaks. (Auth.)

  19. Evaluation of rod insertion issue for NPP Krsko

    International Nuclear Information System (INIS)

    Gunstek, A.; Kurincic, B.

    1998-01-01

    The last couple of years incident with control rods sticking in lower part of the fuel assemblies have been reported of several reactor operators and fuel vendors throughout of the world. Several activities were initiated immediately to determine the root cause of incomplete rod insertion. The purpose of this activities were to collect plants trip history data and testing results, review of available worldwide experience, review of plant operation and fuel management, detailed review of manufacturing and material property and to maintain detailed mechanical model. In this paper, we will present activities in Nuclear Power Plant Krsko which have been performed after NRC initiated the Root Cause Process (NRC Bulletin 96-01). NPP Krsko has not experienced rod insertion anomaly yet but anyway the additional tests were carried out. Rod drop time measurements that were performed normally at beginning of cycle at nominal temperature and pressure (HSB mode) have been extended also to end of cycle. Rod drop time, velocity of dropped rods and magnitudes of the initial recoil bounces vs. burnup were also analyzed. Also RCCA drag test with upper internals in place and drive shafts attached to RCCAs has been performed since then. At last two outages (1997 and 1998) drag test were carried out with digital scale meter to gather additional information. In addition to that, the reload core design has been performed with new constrains on rodded fuel assembly burnup as proposed by the industry.(author)

  20. 118-C-4 Horizontal Rod Cave characterization plan

    International Nuclear Information System (INIS)

    1997-08-01

    This characterization plan provides instructions for obtaining and analyzing samples for waste designation and disposal. The 118-C-4 Horizontal Rod Cave is located in the 100-C Area about 328 ft (100 m) southeast of the 105-C Reactor (Figure 1). The 118-C-4 Horizontal Rod Cave (Figure 2) is a reinforced concrete bunker approximately 70- ft (21.3-m) long, 7-ft (2.1-m) high, and 12-ft (3.6-m) wide, with triangular-shaped concrete ends 3-ft (0.9-m) high. The rod cave was used to store radiologically contaminated control-rod tips. If control rod tips are present, release of control rod activation products will not change expectations with respect to principal contaminants. The north portion of the cave is empty and the south portion contains two aluminum tubes that may contain rod tips (Figure 3). The caves are contaminated with activation and fission products (e.g., 60Co and 137Cs) common to the 100 Areas (see Appendix for data). Dose rates up to 0.7 mR/hr were measured in the south cave and 0.5 mR/hr in the north cave during an inspection of the facility in December 1996

  1. Anisotropy in CdSe quantum rods

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liang-shi [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    The size-dependent optical and electronic properties of semiconductor nanocrystals have drawn much attention in the past decade, and have been very well understood for spherical ones. The advent of the synthetic methods to make rod-like CdSe nanocrystals with wurtzite structure has offered us a new opportunity to study their properties as functions of their shape. This dissertation includes three main parts: synthesis of CdSe nanorods with tightly controlled widths and lengths, their optical and dielectric properties, and their large-scale assembly, all of which are either directly or indirectly caused by the uniaxial crystallographic structure of wurtzite CdSe. The hexagonal wurtzite structure is believed to be the primary reason for the growth of CdSe nanorods. It represents itself in the kinetic stabilization of the rod-like particles over the spherical ones in the presence of phosphonic acids. By varying the composition of the surfactant mixture used for synthesis we have achieved tight control of the widths and lengths of the nanorods. The synthesis of monodisperse CdSe nanorods enables us to systematically study their size-dependent properties. For example, room temperature single particle fluorescence spectroscopy has shown that nanorods emit linearly polarized photoluminescence. Theoretical calculations have shown that it is due to the crossing between the two highest occupied electronic levels with increasing aspect ratio. We also measured the permanent electric dipole moment of the nanorods with transient electric birefringence technique. Experimental results on nanorods with different sizes show that the dipole moment is linear to the particle volume, indicating that it originates from the non-centrosymmetric hexagonal lattice. The elongation of the nanocrystals also results in the anisotropic inter-particle interaction. One of the consequences is the formation of liquid crystalline phases when the nanorods are dispersed in solvent to a high enough

  2. Review of FFTF and CRBRP control rod systems designs

    International Nuclear Information System (INIS)

    Pitterle, T.A.; Lagally, H.O.

    1977-01-01

    The evolution of the primary control rod system design for FFTF and CRBR, beginning with the initial choice of the basic concepts, is described. The significant component and systems tests are reviewed together with the test results which referenced the development of the CRBR primary control rod system design. Modifications to the concepts and detail designs of the FFTF control rod system were required principally to satisfy the requirements of CRBR, and at the same time incorporating design refinements shown desirable by the tests

  3. Gamma-ray spectroscopy on irradiated fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Terremoto, Luis Antonio Albiac [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear], e-mail: laaterre@ipen.br

    2009-07-01

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  4. Axial gas flow in irradiated PWR fuel rods

    International Nuclear Information System (INIS)

    Dagbjartsson, S.J.; Murdock, B.A.; Owen, D.E.; MacDonald, P.E.

    1977-09-01

    Transient and steady state axial gas flow experiments were performed on six irradiated, commercial pressurized water reactor fuel rods at ambient temperature and 533 K. Laminar flow equations, as used in the FRAP-T2 and SSYST fuel behavior codes, were used with the gas flow results to calculate effective fuel rod radial gaps. The results of these analyses were compared with measured gap sizes obtained from metallographic examination of one fuel rod. Using measured gap sizes as input, the SSYST code was used to calculate pressure drops and mass fluxes and the results were compared with the experimental gas flow data

  5. Gamma-ray spectroscopy on irradiated fuel rods

    International Nuclear Information System (INIS)

    Terremoto, Luis Antonio Albiac

    2009-01-01

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  6. System for fuel rod removal from a reactor module

    International Nuclear Information System (INIS)

    Matchett, R.L.; Roof, O.R.; Kikta, T.J.; Wilczynski, R.; Nilsen, R.J.; Bacvinskas, W.S.; Fodor, G.

    1990-01-01

    This patent describes a robotic system for remote underwater withdrawal of the fuel rods from fuel modules of a light water breeder reactor includes a collet/grapple assembly for gripping and removing fuel rods in each module, which is positioned by use of a winch and a radial support means attached to a vertical support tube which is mounted over the fuel module. A programmable logic controller in conjunction with a microcomputer, provides control for the accurate positioning and pulling force of the rod grapple assembly. Closed circuit television cameras are provided which aid in operator interface with the robotic system

  7. Characteristics of zinc sulphide nanostructures grown onsilica modified-polyaniline with polymerization time-dependent

    Science.gov (United States)

    Potestas, M.; Alguno, A.; Vequizo, R.; Sambo, B. R.; Odarve, M. K.

    2015-06-01

    Growth of zinc sulphide (ZnS) nanostructures on silica modified-polyaniline (SM- PAni) with polymerization time-dependent was prepared using chemical bath deposition (CBD) technique. The grown samples were characterized by scanning electron microscopy (SEM) equipped with energy dispersive x-ray spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR). SEM images revealed that polyaniline rod-like nanostructures and ZnS nanospheres were successfully grown. The average diameter of the grown ZnS nanospheres did not significantly change by changing the growth time of the polyaniline. However, ZnS nanospheres grown with longer polymerization time of PAni is less dense and loosely bound as compared to shorter polymerization time of PAni. The less density of ZnS nanostructures with longer polymerization time of PAni may be due to the presence of PAni agglomerates that hinders the growth of ZnS nanospheres. Furthermore, FTIR spectra confirmed that the grown polyaniline is of emeraldine salt oxidation state which is the most conductive state of PAni.

  8. Behavior of water reactor fuel rod

    International Nuclear Information System (INIS)

    Yanagisawa, Kazuaki

    1990-08-01

    This paper reviewed the fuels used widely in forms of (1) Zircaloy-sheathed UO 2 fuel in light water-commercial power reactor, (2) Zircaloy-sheathed PuO 2 -UO 2 fuel in plutonium-thermal reactor and advanced reactor (ATR), (3) aluminide and silicide fuel in Material Testing Reactors. From fundamental view points, physical/chemical properties and irradiation behaviors of both fuels and zircaloy claddings are briefly reviewed in chapters 1 and 2. Change of the fuel rod physical parameters with progress of burn-up are summed up in chapter 3. Some fuel troubles and failures encountered in past usage of worldwide LWR fuels are introduced with counterplans taken. In the last session of this chapter, recent results of R and D works have been carried out by fuel vendors are reviewed. Especially, in-core behaviors of PCI-remedy fuels developed to use for high burn-up extension and for load-follow operation are highlighted. Reactor accidents occurred through past forty years are surveyed and reviewed. Fuel behaviors during the reactivity initiated accident (RIA), the power-coolant mismatch (PCM), and the loss-of-coolant accident (LOCA) are taken into this review by using disclosed literatures. Safety criteria being used in Japanese licensing authorities are introduced relating to the fuel design limit. (author)

  9. Hydraulic Rod Drives for the CAREM Reactor

    International Nuclear Information System (INIS)

    Mazzi, R.O

    2000-01-01

    CAREM belongs to those considered innovative reactors and their main design goal is obtain a significant improvement in safety.Requirements for the design of the first shutdown systems (FSS) is one of the mayor challenges from functional and reliability point of view, among most of the system of a nuclear reactor.Thus, the design of First Shutdown System must be in accordance with both, the system and the specific design criteria of the CAREM concept.In order to choose the best option for the control rod drive device, three different alternatives have been analysed in the frame of the Project.This paper discusses the advantages and disadvantages of each option and presents the main reasons to select the hydraulic type as the most promising one.The principles and main characteristics of the selected system are explained and the main goals to be obtained during development activities, in order to obtain a reliable design to successfully comply with operating requirements for reactor service are also presented

  10. Nuclear reactor shutdown control rod assembly

    International Nuclear Information System (INIS)

    Bilibin, K.

    1988-01-01

    This patent describes a nuclear reactor having a reactor core and a reactor coolant flowing therethrough, a temperature responsive, self-actuated nuclear reactor shutdown control rod assembly, comprising: an upper drive line terminating at its lower end with a substantially cylindrical wall member having inner and outer surfaces; a lower drive line having a lower end adapted to be attached to a neutron absorber; a ring movable disposed about the outer surface of the wall member of the upper drive line; thermal actuation means adapted to be in heat exchange relationship with coolant in an associated reactor core and in contact with the ring, and balls located within the openings in the upper drive line. When reactor coolant approaches a predetermined design temperature the actuation means moves the ring sufficiently so that the balls move radially out from the recess and into the space formed by the second portion of the ring thereby removing the vertical support for the lower drive line such that the lower drive line moves downwardly and inserts an associated neutron absorber into an associated reactor core resulting in automatic reduction of reactor power

  11. Control rod driving hydraulic pressure device

    International Nuclear Information System (INIS)

    Ogawa, Masahide.

    1993-01-01

    The present invention concerns a control rod driving hydraulic device of a BWR type reactor, and provides an improvement for a means for supplying mechanical seal flashing water of a pump. That is, a mechanical seal flashing pipeline is branched at the downstream of a pressure-reducing orifice and connected to a minimum flow pipeline. With such a constitution, the minimum flow pipeline is connected to a minimum flow pipeline of an auxiliary pump at the downstream of the pressure-reducing orifice and returned to a suction pipeline of the pump. Pressure at the downstream of the pressure-reducing orifice is set, in the orifice, to a pressure required for mechanical seal flashing. Accordingly, the mechanical seal flashing pipeline is connected and a part of minimum flow rate is utilized, thereby enabling to cool mechanical seals. As a result, flow rate of the mechanical flashing water which has been flown out can be saved. The exhaustion amount from the pump can be reduced, to decrease the shaft power and reduce the capacity of the motor. (I.S.)

  12. Electromotor control rod drive for nuclear reactors

    International Nuclear Information System (INIS)

    Baker, S.M.

    1975-01-01

    The positioning of a control rod arranged in a pressure vessel takes place with a drive. This protrudes out of the pressure vessel through a support and is formed from a rotating field motor with energy source, e.g. alternating current connection. Its stator surrounds a section of a pressure casing which covers the length of the drive. The rotor is arranged in the pressure casing and interacts with a shaft lying in the rotation axis. Furthermore, segments are hinged on it, each of which forms two arms of a rocker. Each segment can be revolved against a storing force in a plane containing the rotation axis, through the stator field acting on one of the rocker arms. In order that the drive motor is automatically blocked should the electricity supply fail, the other rocker arm can be connected with a fixed cased component of the drive having the effect of a friction break or a form-locking mechanical catch. (DG/LH) [de

  13. Fluorescent colloidal silica rods - synthesis and phase behavior

    Science.gov (United States)

    Kuijk, A.

    2012-01-01

    Although the experimental study of spherical colloids has been extensive, similar studies on rod-like particles are rare because suitable model systems are scarce. To fulfill this need, we present the synthesis of monodisperse rod-like silica colloids with tunable dimensions. Rods were produced with diameters of 200 nm and larger and lengths up to 10 µm, which resulted in aspect ratios ranging from 1 to 25. The growth mechanism of these rods involves emulsion droplets of water in pentanol, inside which silica condensation takes place. Since the silica nucleus is attached to the water/pentanol interface, the supply of reactants to the nucleus is anisotropic, causing it to grow on one side only, which results in rod formation. The rods were made suitable for quantitative real-space studies by confocal laser scanning microscopy. Several methods of fluorescent labeling are presented that resulted in constant fluorescence levels, gradients from one rod-end to the other, and even patterns of two colors. Single particle imaging was achieved by creating core-shell rods that had a fluorescent core and a non-fluorescent shell. Alternatively, the rods could be dispersed in a solvent with a low dielectric constant to induce micron-sized double layers. To enable quantitative measurements, a tracking algorithm was developed that identifies the rods' positions and orientations. The newly developed model system was used to study the phase behavior of rods. By combining real-space confocal laser scanning microscopy and small angle X-ray scattering methods, a phase diagram depending on concentration and aspect ratio was constructed, which shows good qualitative agreement with simulation results in literature. This phase diagram includes nematic and smectic phases for the higher aspect ratios. Also, the effect of external fields (electric fields, shear and templates) on the phase behavior was studied. In an electric field, rods aligned themselves with the applied field due to an

  14. Results of Post Irradiation Examinations of VVER Leaky Rods

    Energy Technology Data Exchange (ETDEWEB)

    Markov, D.; Perepelkin, S.; Polenok, V.; Zhitelev, V.; Mayorshina, G. [Head of Fuel Research Department, JSC ' SSC RIAR' , 433510, Dimitrovgrad-10, Ulyanovsk region (Russian Federation)

    2009-06-15

    The most important requirement imposed on fuel elements is to maintain integrity of fuel rod claddings under operation, storage and transportation, since it is directly related to the operational safety. However, failed rod claddings are sometimes observed under reactor operation. Identification and unloading of fuel assemblies with leaky rods from VVER is available only at the time of planned preventive maintenance. An unscheduled reactor shutdown due to the excess of coolant activity limit as well as a preterm unloading of the fuel assembly cause economic damage to nuclear plant. Therefore, models and calculation codes were developed to forecast coolant contamination and failed fuel rod behavior. Criteria based on calculations were set to determine the admissible number of the failed rods in core and the opportunity to continue the reactor operation or pre-term unloading of the fuel assembly with the failed rods. Nevertheless, to prevent the fuel rod failure (for unfailing operation) it is necessary to reveal disadvantages of the design, fabrication method and fuel operation conditions, and to eliminate defects. The most complete and significant information about spent fuel assemblies may be received following the post irradiation material examinations. In order to reveal failure origins and mechanism of changes in VVER fuel and failed rod cladding condition depending on the operation, the examinations of 12 VVER-1000 fuel assemblies and 3 VVER-440 fuel assemblies, operated under normal conditions up to the fuel burnup 13..47 MWd/kgU were carried out. To evaluate the rod cladding condition, reveal defects and determine their parameters, the ultrasonic control of cladding integrity, surface visual inspection, eddy current defectoscopy, measurement of geometrical parameters were applied. In separate cases we used the metallography, measured the hydrogen percentage and carried out the mechanical tests of o-ring samples. The pellet condition was evaluated in

  15. Properties of fiber reinforced plastic rods for prestressing tendons of concrete. 8. ; Dynamic fatigue behavior of reinforced plastics rods. Prestressed concrete yo FRP kinchozai no tokusei. 8. ; FRP rod no doteki hiro tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Uomoto, T.; Nishimura, T. (The University of Tokyo, Tokyo (Japan). Institute of Industrial Science)

    1994-01-01

    This paper describes the result of experiments on dynamic fatigue and creep characteristics of plastic rods reinforced by aramid, glass and carbon fibers (AFRP rods, GFRP rods, and CFRP rods) used as prestressing tendons of concrete. Although the dynamic fatigue limit for generally used FRP rods is not known, the fatigue strength was found to decrease in the order of AFRP rod > CFRP rod > GFRP rod. However, AFRP rods have shown a sharp decrease in the fatigue strength starting from around one million dynamic loading iterations. The AFRP and GFRP rods have had creep fracture existed in fatigue fracture at a high stress of 100 kg/mm[sup 2] or higher, and fatigue fracture existed due to dynamic fatigue below that stress. Residual tensile strength after fatigue due to two-million iterative loadings was about 83% of the average tensile strength for the AFRP rods, and about 69% for the GFRP rods, whereas that for CFRP rods was about the same as the average strength. 8 refs., 6 figs., 1 tab.

  16. Results from In-pile experiments on LWR fuel rod behavior under LOCA conditions with unirradiated rods

    International Nuclear Information System (INIS)

    Sepold, L.; Karb, E.H.; Pruessmann, M.

    1981-06-01

    This report summarizes the results of the FR2-in-pile tests at KfK (Kernforschungszentrum Karlsruhe) with unirradiated test rods. The in-pile tests with the objective of investigating the influence of a nuclear environment on the mechanisms of fuel rod failure were being performed with irradiated and unirradiated single rods of a PWR design in the DK loop of the FR2 reactor. The main parameter of the test program was the burnup, ranging from 2.500 to 35.000 MWd/t. The program with unirradiated specimens comprised the series A and B with a total of 14 tests. (orig.) [de

  17. Positron Spectroscopy of Hydrothermally Grown Actinide Oxides

    Science.gov (United States)

    2014-03-27

    POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES THESIS Edward C. Schneider...United States Government. AFIT-ENP-14-M-33 POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES THESIS...33 POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES Edward C. Schneider, BS Captain, USAF Approved

  18. Physics analysis of the gang partial rod drive event

    International Nuclear Information System (INIS)

    Boman, C.; Frost, R.L.

    1992-08-01

    During the routine positioning of partial-length control rods in Gang 3 on the afternoon of Monday, July 27, 1992, the partial-length rods continued to drive into the reactor even after the operator released the controlling toggle switch. In response to this occurrence, the Safety Analysis and Engineering Services Group (SAEG) requested that the Applied Physics Group (APG) analyze the gang partial rod drive event. Although similar accident scenarios were considered in analysis for Chapter 15 of the Safety Analysis Report (SAR), APG and SAEG conferred and agreed that this particular type of gang partial-length rod motion event was not included in the SAR. This report details this analysis

  19. Solitary waves in a magneto-electro-elastic circular rod

    International Nuclear Information System (INIS)

    Xue, C X; Pan, E; Zhang, S Y

    2011-01-01

    A simple nonlinear model is proposed in this paper to study the solitary wave in a circular magneto-electro-elastic rod. Based on the constitutive relation for transversely isotropic piezoelectric and piezomagnetic materials, combined with the differential equations of motion, we derive the longitudinal wave motion equation in a long circular rod. The nonlinearity considered is geometrically associated with the nonlinear normal strain in the longitudinal rod direction and the transverse Poisson's effect is included by introducing the effective Poisson's ratio. The nonlinear solitary wave equation is solved by the Jacobi elliptic function expansion method and numerical examples demonstrate not only the existence of such a wave but also some interesting characteristics of the solitary wave in the rod made of different multiphase coupled materials

  20. Computation of reactor control rod drop time under accident conditions

    International Nuclear Information System (INIS)

    Dou Yikang; Yao Weida; Yang Renan; Jiang Nanyan

    1998-01-01

    The computational method of reactor control rod drop time under accident conditions lies mainly in establishing forced vibration equations for the components under action of outside forces on control rod driven line and motion equation for the control rod moving in vertical direction. The above two kinds of equations are connected by considering the impact effects between control rod and its outside components. Finite difference method is adopted to make discretization of the vibration equations and Wilson-θ method is applied to deal with the time history problem. The non-linearity caused by impact is iteratively treated with modified Newton method. Some experimental results are used to validate the validity and reliability of the computational method. Theoretical and experimental testing problems show that the computer program based on the computational method is applicable and reliable. The program can act as an effective tool of design by analysis and safety analysis for the relevant components

  1. Device for detecting defective nuclear reactor fuel rods

    International Nuclear Information System (INIS)

    Steven, J.

    1976-01-01

    A moisture sensor is provided for a nuclear fuel rod for water-cooled nuclear reactors wherein moisture can be present. The fuel rod has an end cap and a charge of nuclear fuel. The moisture sensor is disposed between the end cap and the charge and serves to detect a leak in the fuel rod. The moisture sensor includes a capsule-like housing having an inner space and having openings through which moisture can pass into the inner space in the event of a leak in the fuel rod. Ferromagnetic material is disposed in the inner space of the housing together with a moisture detector responsive to moisture for altering the diposition of the ferromagnetic material in the inner space. 5 claims, 6 drawing figures

  2. Design requirement on KALIMER control rod assembly duct

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, W.; Kang, H. Y.; Nam, C.; Kim, J. O.; Kim, Y. J

    1998-03-01

    This document establishes the design guidelines which are needs for designing the control rod assembly duct of the KALIMER as design requirements. it describes control rod assembly duct of the KALIMER and its requirements that includes functional requirements, performance requirements, interfacing systems, design limits and strength requirements, seismic requirements, structural requirements, environmental requirements, reliability and safety requirements, standard and codes, QA programs, and other requirements. The control rod system consists of three parts, which are drive mechanism, drive-line, and absorber bundle. This report deals with the absorber bundle and its outer duct only because the others are beyond the scope of fuel system design. The guidelines for design requirements intend to be used for an improved design of the control rod assembly duct of the KALIMER. (author). 19 refs.

  3. Absorber rod bundle actuator in a pressurized water nuclear reactor

    International Nuclear Information System (INIS)

    Martin, J.; Peletan, R.

    1984-01-01

    The invention concerns an absorber rod bundle actuator in a pressurized water reactor with spectral shift control. The device comprises two coaxial control bars. The inner bar is integral with the absorber rod bundle; it has an enlarged zone which acts as a proton under pressure difference across an annular seal which can be radially expanded, the pressure difference allowing to the absorber rod bundles actuating on the piston. When a pressure difference is applied, the seal expands radially by a sufficient amount to make sealing contact with the zone of larger diameter in the outer bar. The invention applies more particularly to reactors with spectral shift control using bundles of fertile rods [fr

  4. The ATLAS LARG ROD G-Links Cooling System

    CERN Document Server

    Hubaut, F; Repain, P; Rossel, F; Vincent, D

    2004-01-01

    In this note is described the water cooling system that will be implemented on the ROD boards of the liquid argon calorimeter detectors in order to guarantee a proper behavior of the optical reception of the data.

  5. Post irradiation examination of control rod assembly of FBTR

    International Nuclear Information System (INIS)

    Anandaraj, V.; Raghu, N.; Venkiteswaran, C.N.; Visweswaran, P.; Vijayakumar, Ran; Jayaraj, V.V.; Padmaprabu, P.; Saravanan, T.; Philip, John; Muralidharan, N.G.; Joseph, Jojo; Kasiviswanathan, K.V.

    2010-01-01

    Six control rods with boron carbide pellets are used in FBTR for shutdown and control of reactor power. One control rod after being subjected to a fluence level of 7.2 x 10 22 n/cm 2 was received for post irradiation examination (PIE) to assess its irradiation behavior and to investigate the incident of dropping of control rod. Examinations carried out include precise dimensional measurements to investigate the possibility of interference between the control rod and outer sheath, Neutron radiography and x-radiograph to assess the integrity of the boron carbide pellets and other internals, density measurements to assess the swelling behaviour of boron carbide pellets and metallographic examinations to study the cracking behaviour and microstructural changes in the pellet and the clad. Depletion of B 10 in the pellet was studied using time of flight mass spectrometry. The paper highlights the examinations and results of the PIE carried out. (author)

  6. Vibrations of post-buckled rods: The singular inextensible limit

    KAUST Repository

    Neukirch, Sébastien

    2012-01-01

    The small-amplitude in-plane vibrations of an elastic rod clamped at both extremities are studied. The rod is modeled as an extensible, shearable, planar Kirchhoff elastic rod under large displacements and rotations, and the vibration frequencies are computed both analytically and numerically as a function of the loading. Of particular interest is the variation of mode frequencies as the load is increased through the buckling threshold. While for some modes there are no qualitative changes in the mode frequencies, other frequencies experience rapid variations after the buckling threshold, the thinner the rod, the more abrupt the variations. Eventually, a mismatch for half of the frequencies at buckling arises between the zero thickness limit of the extensible model and the inextensible model. © 2011 Elsevier Ltd. All rights reserved.

  7. Design requirement on KALIMER control rod assembly duct

    International Nuclear Information System (INIS)

    Hwang, W.; Kang, H. Y.; Nam, C.; Kim, J. O.; Kim, Y. J.

    1998-03-01

    This document establishes the design guidelines which are needs for designing the control rod assembly duct of the KALIMER as design requirements. it describes control rod assembly duct of the KALIMER and its requirements that includes functional requirements, performance requirements, interfacing systems, design limits and strength requirements, seismic requirements, structural requirements, environmental requirements, reliability and safety requirements, standard and codes, QA programs, and other requirements. The control rod system consists of three parts, which are drive mechanism, drive-line, and absorber bundle. This report deals with the absorber bundle and its outer duct only because the others are beyond the scope of fuel system design. The guidelines for design requirements intend to be used for an improved design of the control rod assembly duct of the KALIMER. (author). 19 refs

  8. Ultrasonic detection of cracks in uniaxial glass fibre rods

    CSIR Research Space (South Africa)

    Loveday, PW

    2006-01-01

    Full Text Available A non-destructive examination procedure based on a guided wave inspection approach is used for the acoustic examination of glass fibre reinforced composite rods. This paper contains an investigation into the characteristics of guided wave...

  9. Safety coupling for a control rod of a nuclear reactor

    International Nuclear Information System (INIS)

    Mindnich, F.R.; Friedrichs, H.; Schoettle, J.

    1978-01-01

    A coupling is presented between a control rod and the drive shafft arranged below. The construction of this coupling is designed in such a way that the usual sealing maesures against the escape of coolant are reduced. (TK) [de

  10. Failed fuel rod detection method by ultrasonic wave

    International Nuclear Information System (INIS)

    Takamatsu, Masatoshi; Muraoka, Shoichi; Ono, Yukio; Yasojima, Yujiro.

    1990-01-01

    Ultrasonic wave signals sent from an ultrasonic receiving element are supplied to an evaluation circuit by way of a gate. A table for gate opening and closing timings at the detecting position in each of the fuel rods in a fuel assembly is stored in a memory. A fuel rod is placed between an ultrasonic transmitting element and the receiving element to determine the positions of the transmitting element and the receiving element by positional sensors. The opening and closing timings at the positions corresponding to the result of the detection are read out from the table, and the gates are opened and closed by the timing. This can introduce the ultrasonic wave signals transmitted through a control rod always to the evaluation circuit passing through the gate. Accordingly, the state of failure of the fuel rod can be detected accurately. (I.N.)

  11. On the resonant behavior of longitudinally vibrating accreting rods

    CSIR Research Space (South Africa)

    Shatalov, M

    2012-09-01

    Full Text Available The theory of accreting structures is a new and fast developing branch of analytical mechanics basing on the theory of partial differential and integral equations. In the present paper the authors analyze qualitative properties of accreting rods...

  12. Measurement of blockage in deformed LWR multi-rod arrays

    International Nuclear Information System (INIS)

    Hindle, E.D.; Jones, C.; Whitty, S.

    1983-01-01

    This paper critically reviews the current methods used for measuring blockage in multi-rod arrays and discusses their application. A new definition which overcomes the deficiencies of the previous methods is proposed. Also examples of the application of automatic computerised techniques to directly measure rod strain, blockage, sub-channel blockage and perimeter changes from photographs of sections through deformed arrays are presented. (author)

  13. Double-clad nuclear-fuel safety rod

    Science.gov (United States)

    McCarthy, W.H.; Atcheson, D.B.

    1981-12-30

    A device for shutting down a nuclear reactor during an undercooling or overpower event, whether or not the reactor's scram system operates properly. This is accomplished by double-clad fuel safety rods positioned at various locations throughout the reactor core, wherein melting of a secondary internal cladding of the rod allows the fuel column therein to shift from the reactor core to place the reactor in a subcritical condition.

  14. Downflow film boiling in a rod bundle at low pressure

    International Nuclear Information System (INIS)

    Hochreiter, L.E.; Rosal, E.R.; Fayfich, R.R.

    1978-01-01

    A series of low pressure downflow film boiling heat transfer experiments were conducted in a 14-foot (4.27 m) long electrically heater rod bundle containing 336 heater rods. The resulting data was compared with the Dougall-Rohsenow dispersed flow film boiling correlation. The data was found to lie below this correlation as the quality was increased. It is believed that buoyancy effects decreased the heat transfer in downflow film boiling. (author)

  15. CHF prediction in rod bundles using round tube data

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Wallen F.; Veloso, Maria A.F.; Pereira, Cláubia; Costa, Antonella L., E-mail: wallenfds@yahoo.com.br, E-mail: mdora@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    The present work concerns the use of 1995 CHF table for uniformly heated round tubes, developed jointly by Canadian and Russian researchers, for the prediction of critical heat fluxes in rod bundles geometries. Comparisons between measured and calculated critical heat fluxes indicate that this table could be applied to rod bundles provided that a suitable correction factor is employed. The tolerance limits associated with the departure from nucleate boiling ratio (DNBR) are evaluated by using statistical analysis. (author)

  16. Modelling of fuel rod hydriding failures in water reactors

    International Nuclear Information System (INIS)

    Afanas'eva, E.Yu.; Evdokimov, I.A.; Khoruzhij, O.V.; Likhanskij, V.V.; Sorokin, A.A.

    2003-01-01

    Mechanistic models which were developed to describe primary hydriding phenomena in claddings of initially intact rods with residual moisture are described. The models include the following key processes: fuel rod thermal behavior, UO 2 fuel oxidation in steam-hydrogen atmosphere under irradiation, hydrogen diffusion in zirconium and in the hydride, growth of the hydride phase. Fuel rod thermomechanical behavior is calculated by using RTOP integral fuel code. An oxidation model represents the effects of temperature dynamics and temperature profile along fuel axis and radius on fuel oxidation as well as on hydrogen accumulation inside the fuel rod. Along with ordinary thermal dissociation of water molecules, the oxidation model also addresses radiolysis of the steam-hydrogen mixture due to fission fragments. The present radiolysis model takes into account the effects of the gas mixture composition, temperature and pressure. A new model of cladding hydriding is proposed in which calculation of the massive hydride growth is performed in 2-D geometry. Hydrogen transport in zirconium cladding is modeled with account for thermodiffusion. The RTOP code comprising the models developed allows us to calculate different scenarios of hydriding rod failures under given operation conditions. Test calculations were carried out and compared to available data. It is shown that there are threshold values of initial steam content inside the intact fuel rod which lead to the possibility of through-cladding hydride growth and formation of the primary defect. The threshold values depend on the oxidation state of the cladding inner surface, linear power profile in the fuel rod, fuel rod geometry, cladding temperature conditions and hydrogen diffusivities in zirconium and zirconium hydride

  17. Components inspection of Monju, a sodium bonded type control rod

    International Nuclear Information System (INIS)

    Harada, Kiyoshi; Matsushita, Yuichi; Lee, Chunchan; Abe, Hideaki; Watahiki, Naohisa

    2002-03-01

    This Report addresses a result of a sodium test conducted on components of a Double Poral Filter Sodium Bonded Type Control Rod that is expected to be a next generation, long life Control Rod. Upper and lower Poral Filter Sodium Bonded Type Control Rod components were mocked up to conduct a sodium test. During the test, sodium chargeability, formation of Gas Plenum at the upper part of the components, sodium drain-ability and NaOH clean-ability were recognized under actual plant condition. The following are results obtained: (1) Sodium Chargeability at Control Rod Insertion to EVST. Sodium was charged into the components when the mocked-up was inserted in sodium of 190degC, with insertion speed of 6 m/min which is an actual insertion speed to EVST. (2) Formation of Upper Gas Plenum by Helium Gas generated in Control Rod Components Gas Plenum formation within deviation of 9% was confirmed by releasing helium gas into the mocked-up which is immersed in sodium of 620degC and 190degC. Length of Gas Plenum is confirmed to be retained in certain length even if helium gas is further released into formed Gas Plenum. (3) Sodium Drain-ability of Control Rod Components when Drawing from EVST. Drain-ability was confirmed to be sufficient and no sodium residue was found in the mocked-up when the mocked-up was drawn out from sodium of 190degC, with drawing speed of 6 m/min which is an actual drawing speed from EVST. (4) Clean-ability of NaOH Solution against Sodium Residue in Control Rod Components. Sodium and NaOH solution reacted calmly, however, clean-ability was not sufficient. When Sodium fully remained in Control Rod Components, it made circulation of NaOH solution not enough. (author)

  18. Normal temperature ventilating homogenity test of control rod drive mechanism

    International Nuclear Information System (INIS)

    Zhu Longxing.

    1987-01-01

    This paper describes the cooling for the control rod drive mechanism. It emphatically introduces some problems which must be considered in the test on ventilating homogenity under normal temperature for the control rod drive mechanism at the top of a reactor such as the selection of cooling shroud assemblies, installed position of ducts, volume of the static pressure container, etc. The test data of blowing-in and induced draft are compared and analysed

  19. Apparatus for injection casting metallic nuclear energy fuel rods

    Science.gov (United States)

    Seidel, Bobby R.; Tracy, Donald B.; Griffiths, Vernon

    1991-01-01

    Molds for making metallic nuclear fuel rods are provided which present reduced risks to the environment by reducing radioactive waste. In one embodiment, the mold is consumable with the fuel rod, and in another embodiment, part of the mold can be re-used. Several molds can be arranged together in a cascaded manner, if desired, or several long cavities can be integrated in a monolithic multiple cavity re-usable mold.

  20. Status and development of RBMK fuel rods and reactor materials

    International Nuclear Information System (INIS)

    Bibilashvili, Yu.K.; Reshetnikov, F.G.; Ioltukhovsky, A.G.

    1998-01-01

    The paper presents current status and development of RBMK fuel rods and reactor materials. With regard to fuel rod cladding the following issues have been discussed: corrosion, tensile properties, welding technology and testing of an alternative cladding alloy with a composition of Zr-Nb-Sn-Fe. Erbium doped fuel has been suggested for safety improvement. Also analysis of fuel reliability is presented in the paper. (author)

  1. Computer program for automatic generation of BWR control rod patterns

    International Nuclear Information System (INIS)

    Taner, M.S.; Levine, S.H.; Hsia, M.Y.

    1990-01-01

    A computer program named OCTOPUS has been developed to automatically determine a control rod pattern that approximates some desired target power distribution as closely as possible without violating any thermal safety or reactor criticality constraints. The program OCTOPUS performs a semi-optimization task based on the method of approximation programming (MAP) to develop control rod patterns. The SIMULATE-E code is used to determine the nucleonic characteristics of the reactor core state

  2. Estimating modal instability threshold for photonic crystal rod fiber amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Laurila, Marko

    2013-01-01

    We present a semi-analytic numerical model to estimate the transverse modal instability (TMI) threshold for photonic crystal rod amplifiers. The model includes thermally induced waveguide perturbations in the fiber cross section modeled with finite element simulations, and the relative intensity...... noise (RIN) of the seed laser, which seeds mode coupling between the fundamental and higher order mode. The TMI threshold is predicted to ~370 W – 440 W depending on RIN for the distributed modal filtering rod fiber....

  3. Activity determination of the Am-241 radioactive lightning rods

    International Nuclear Information System (INIS)

    Dellamano, Jose C.; Minematsu, Denise; Potiens Jr, Ademar J.

    2008-01-01

    Full text: The radioactive lightning rods had been manufactured in Brazil up to 1989, when the Comissao Nacional de Energia Nuclear (CNEN) lifted the license for manufacture, commerce and installation of these devices. Since this date, the radioactive lightning rods have been replaced for conventional protection systems against electric discharges and have been sent to the institutes subordinated to the CNEN, amongst them the Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP). The radioactive lightning rods are constituted in its majority for a central metallic rod where the plates are mounted. Am-241 radioactive sources are fixed in these plates. The treatment of these devices is made in a glove box, where mechanically the sources are separate of the plates and connecting rods, placed in a metallic package and stored for posterior characterization, final packaging, intermediate storage and final disposal. In accordance with manufacturers information had been installed in Brazil, approximately 75,000 units with activities varying between 25 and 92 MBq. Preliminary studies were carried out in some of the 16,000 lightning rods received by the Laboratorio de Rejeitos Radioativos (LRR) of the IPEN-CNEN/SP, and demonstrated that the variation of the values of activity is very bigger. The implantation of a methodology for the radioisotope characterization of the Am-241 removed sources of the radioactive lightning rods is important because the isotope inventory is necessary for the certification of the processes considered for packaging and storage, besides being indispensable data for the final disposal. It is convenient mentioning that one is not about the determination of activity of a radioactive source with geometry and defined characteristics, but the implantation of a measure protocol for groups of sources that will be used in the routine tasks of the LRR. The current work presents the methodology developed for the radioisotope characterization of the Am

  4. Local hydrodynamic characteristics of regular triangular lattice of rods

    International Nuclear Information System (INIS)

    Mantlik, F.; Hejna, J.; Cervenka, J.

    1976-06-01

    Results are presented of an experimental investigation of the friction factor, velocity fields and shear stress distribution around a wetted perimeter in a rod bundle of a triangular lattice with a pitch-to-diameter ratio of 1.17. Measurements were made on 19-rod aerodynamical model at the Reynolds number of 42 300 and 211 000. The results indicated a highly significant effect of secondary flow. (author)

  5. Integrability of a conducting elastic rod in a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sinden, D; Heijden, G H M van der [Centre for Nonlinear Dynamics, University College London, Chadwick Building, Gower Street, London WC1E 6BT (United Kingdom)

    2008-02-01

    We consider the equilibrium equations for a conducting elastic rod placed in a uniform magnetic field, motivated by the problem of electrodynamic space tethers. When expressed in body coordinates the equations are found to sit in a family of non-canonical Hamiltonian systems involving an increasing number of vector fields. These systems, which include the classical Euler and Kirchhoff rods, are shown to be completely integrable in the case of a transversely isotropic rod; they are in fact generated by a Lax pair. For the magnetic rod this gives a physical interpretation to a previously proposed abstract nine-dimensional integrable system. We use the conserved quantities to reduce the equations to a four-dimensional canonical Hamiltonian system, allowing the geometry of the phase space to be investigated through Poincare sections. In the special case where the force in the rod is aligned with the magnetic field the system turns out to be superintegrable, meaning that the phase space breaks down completely into periodic orbits, corresponding to straight twisted rods.

  6. POWER LEVEL EFFECT IN A PWR ROD EJECTION ACCIDENT

    International Nuclear Information System (INIS)

    Diamond, D.J.; Bromley, B.P.; Aronson, A.L.

    2002-01-01

    The purpose of this study is to determine the effect of the initial power level during a rod ejection accident (REA) on the ejected rod worth and the resulting energy deposition in the fuel. The model used is for the hot zero power (HZP) conditions at the end of a typical fuel cycle for the Three Mile Island Unit 1 pressurized water reactor. PARCS , a transient, three-dimensional, two-group neutron nodal diffusion code, coupled with its own thermal-hydraulics model, is used to perform both steady-state and transient simulations. The worth of an ejected control rod is affected by both power level, and the positions of control banks. As the power level is increased, the worth of a single central control rod tends to drop due to thermal-hydraulic feedback and control bank removal, both of which flatten the radial neutron flux and power distributions. Although the peak fuel pellet enthalpy rise during an REA will be greater for a given ejected rod worth at elevated initial power levels, it is more likely the HZP condition will cause a greater net energy deposition because an ejected rod will have the highest worth at HZP. Thus, the HZP condition can be considered the most conservative in a safety evaluation

  7. An Examination Of Fracture Splitting Parameters Of Crackable Connecting Rods

    Directory of Open Access Journals (Sweden)

    Zafer Özdemir

    2000-06-01

    Full Text Available Fracture splitting method is an innovative processing technique in the field of automobile engine connecting rod (con/rod manufacturing. Compared with traditional method, this technique has remarkable advantages. Manufacturing procedures, equipment and tools investment can be decreased and energy consumption reduced remarkably. Furthermore, product quality and bearing capability can also be improved. It provides a high quality, high accuracy and low cost route for producing connecting rods (con/rods. With the many advantages mentioned above, this method has attracted manufacturers attention and has been utilized in many types of con/rod manufacturing. In this article, the method and the advantages it provides, such as materials, notches for fracture splitting, fracture splitting conditions and fracture splitting equipment are discussed in detail. The paper describes an analysis of examination of fracture splitting parameters and optik-SEM fractography of C70S6 crackable connectıng rod. Force and velocity parameters are investigated. That uniform impact force distrubition starting from the starting notch causes brittle and cleavage failure mode is obtained as a result. This induces to decrease the toughness.

  8. Chitin Fiber and Chitosan 3D Composite Rods

    Directory of Open Access Journals (Sweden)

    Zhengke Wang

    2010-01-01

    Full Text Available Chitin fiber (CHF and chitosan (CS 3D composite rods with layer-by-layer structure were constructed by in situ precipitation method. CHF could not be dissolved in acetic acid aqueous solution, but CS could be dissolved due to the different deacetylation degree (D.D between CHF and CS. CHF with undulate surfaces could be observed using SEM to demonstrate that the sufficiently rough surfaces and edges of the fiber could enhance the mechanical combining stress between fiber and matrix. XRD indicated that the crystallinity of CHF/CS composites decreased and CS crystal plane d-spacing of CHF/CS composites became larger than that of pure CS rod. TG analysis showed that mixing a little amount of CHF could enhance thermal stability of CS rod, but when the content of CHF was higher than the optimum amount, its thermal stability decreased. When 0.5% CHF was added into CS matrix, the bending strength and bending modulus of the composite rods arrived at 114.2 MPa and 5.2 GPa, respectively, increased by 23.6% and 26.8% compared with pure CS rods, indicating that CHF/CS composite rods could be a better candidate for bone fracture internal fixation.

  9. Key developments of a rod control system - 15101

    International Nuclear Information System (INIS)

    Pouillot, M.; Jegou, H.; Duthou, A.

    2015-01-01

    The aim of the Rod Control System is to carry out the insertion and withdrawal of control rod clusters to provide the power required by the grid (G-mode control), to control the temperature of the reactor, or to provide negative reactivity margin when the reactor is shut down. The rod control system is not classified important for safety, but its correct operation is essential for the availability of the reactor, as the spurious drop of a single cluster usually results in a reactor trip. Rolls-Royce has been designing, manufacturing and providing rod control systems since 1977, in France, China, Belgium, Korea, and South Africa, as an original manufacturer and for modernization projects. All the corresponding nuclear units share the following features, key points for the system design: -) The power source is a three-phased 260 Vac with neutral, provided by zigzag-coupled alternators; -) The Control Rod Drive Mechanisms (CRDM) are 'three-coil type': Stationary Gripper (SG), Movable Gripper (MG) and Lift Coil (LC); -) Rod clusters are arranged in banks and sub-banks, the bank being composed of one or two sub-banks and a sub-bank is a set of 4 clusters moved simultaneously, the central cluster being an exception; and -) Most of those reactors are operated in G-mode (load following). (authors)

  10. Reactor core and control rod assembly in FBR type reactor

    International Nuclear Information System (INIS)

    Fujimura, Koji; Kawashima, Katsuyuki; Itooka, Satoshi.

    1993-01-01

    Fuel assemblies and control rod assemblies are attached respectively to reactor core support plates each in a cantilever fashion. Intermediate spacer pads are disposed to the lateral side of a wrapper tube just above the fuel rod region. Intermediate space pads are disposed to the lateral side of a control rod guide tube just above a fuel rod region. The thickness of the intermediate spacer pad for the control rod assembly is made smaller than the thickness of the intermediate spacer pad for the fuel assembly. This can prevent contact between intermediate spacer pads of the control guide tube and the fuel assembly even if the temperature of coolants is elevated to thermally expand the intermediate spacer pad, by which the radial displacement amount of the reactor core region along the direction of the height of the control guide tube is reduced substantially to zero. Accordingly, contribution of the control rod assembly to the radial expansion reactivity can be reduced to zero or negative level, by which the effect of the negative radial expansion reactivity of the reactor is increased to improve the safety upon thermal transient stage, for example, loss of coolant flow rate accident. (I.N.)

  11. Calculation method for control rod dropping time in reactor

    International Nuclear Information System (INIS)

    Nogami, Takeki; Kato, Yoshifumi; Ishino, Jun-ichi; Doi, Isamu.

    1996-01-01

    If a control rod starts dropping, the dropping speed is rapidly increased, then settled substantially constant, rapidly decreased when it reaches a dash pot. A second detection signal generated by removing an AC component from a first detection signal is differentiated twice. The time when the maximum value among the twice differentiated values is generated is determined as a time when the control rods starts dropping. The time when minimum value among the twice differentiated values is generated is determined as a time when the control rod reaches the dash pot of the reactor. The measuring time within a range from the time when the control rod starts dropping to the time when the control rod reaches the dash pot of the reactor is determined. As a result, processing for the calculation of the dropping start time and dash pot reaching time of the control rod can be automatized. Further, it is suffice to conduct differentiation twice till the reaching time, which can facilitate the processing thereby enabling to determine a reliable time range. (N.H.)

  12. Rod internal pressure quantification and distribution analysis using Frapcon

    Energy Technology Data Exchange (ETDEWEB)

    Jessee, Matthew Anderson [ORNL; Wieselquist, William A [ORNL; Ivanov, Kostadin [Pennsylvania State University, University Park

    2015-09-01

    This report documents work performed supporting the Department of Energy (DOE) Office of Nuclear Energy (NE) Fuel Cycle Technologies Used Fuel Disposition Campaign (UFDC) under work breakdown structure element 1.02.08.10, ST Analysis. In particular, this report fulfills the M4 milestone M4FT- 15OR0810036, Quantify effects of power uncertainty on fuel assembly characteristics, within work package FT-15OR081003 ST Analysis-ORNL. This research was also supported by the Consortium for Advanced Simulation of Light Water Reactors (http://www.casl.gov), an Energy Innovation Hub (http://www.energy.gov/hubs) for Modeling and Simulation of Nuclear Reactors under U.S. Department of Energy Contract No. DE-AC05-00OR22725. The discharge rod internal pressure (RIP) and cladding hoop stress (CHS) distributions are quantified for Watts Bar Nuclear Unit 1 (WBN1) fuel rods by modeling core cycle design data, operation data (including modeling significant trips and downpowers), and as-built fuel enrichments and densities of each fuel rod in FRAPCON-3.5. A methodology is developed which tracks inter-cycle assembly movements and assembly batch fabrication information to build individual FRAPCON inputs for each evaluated WBN1 fuel rod. An alternate model for the amount of helium released from the zirconium diboride (ZrB2) integral fuel burnable absorber (IFBA) layer is derived and applied to FRAPCON output data to quantify the RIP and CHS for these types of fuel rods. SCALE/Polaris is used to quantify fuel rodspecific spectral quantities and the amount of gaseous fission products produced in the fuel for use in FRAPCON inputs. Fuel rods with ZrB2 IFBA layers (i.e., IFBA rods) are determined to have RIP predictions that are elevated when compared to fuel rod without IFBA layers (i.e., standard rods) despite the fact that IFBA rods often have reduced fill pressures and annular fuel pellets. The primary contributor to elevated RIP predictions at burnups less than and greater than 30 GWd

  13. Instrumentation failure following pedicle subtraction osteotomy: the role of rod material, diameter, and multi-rod constructs.

    Science.gov (United States)

    Luca, Andrea; Ottardi, Claudia; Sasso, Maurizio; Prosdocimo, Liliana; La Barbera, Luigi; Brayda-Bruno, Marco; Galbusera, Fabio; Villa, Tomaso

    2017-03-01

    Pedicle subtraction osteotomy (PSO) has a complication rate noticeably higher than other corrective surgical techniques used for the treatment of spinal sagittal imbalance. In particular, rod breakage and pseudoarthrosis remain burning issues of this technique. Goal of this study was to investigate the biomechanical performance of several hardware constructs. The study was performed using two validated finite element models of the lumbosacral spine (L1-S1) incorporating a PSO on L3 and L4, respectively. Both models were instrumented two levels above and below the osteotomy site. Different combinations of materials (Ti6Al4V and Cr-Co) and device configurations (bilateral single vs. double rod, rod diameters of 5 and 6 mm) were investigated. The loading was represented considering a force of 500 N (imposed along the spinal curvature and connecting the vertebral bodies) and pure moments of 7.5 Nm in flexion-extension, lateral bending and axial rotation. The results were evaluated in terms of range of motion (ROM), load, and stresses acting on the instrumentation. A comparable ROM was found for all the models. The simulations showed a different behavior of the devices: increasing the stiffness an 8-19% increase of the load was calculated on the rod. However, the stress on the instrumentation resulted higher on Cr-Co devices and on smaller rods. The highest stress reduction (up to 50%) was ensured using double rod constructs. The bilateral double parallel rods configuration resulted the best to reduce the stresses on the spinal fixators at the osteotomy site. However, the high loads acting on the rods with respect to the physiologic condition could slow down the bone healing at the osteotomy site.

  14. Calculation of the effectiveness of manual control rods for the reactor of Ignalina NPP Unit 2

    International Nuclear Information System (INIS)

    Bubelis, E.; Pabarcius, R.

    2001-01-01

    On the basis of one of the recent databases of the reactor of Ignalina NPP Unit 2, calculations of the effectiveness of separate manual control rods, groups of manual control rods and axial characteristic of effectiveness of separate manual control rods were performed. The results of the calculations indicated, that all analyzed separate manual control rods have approximately the same effectiveness, which doesn't depend on the location of a control rod in the reactor core layout Manual control rod of the new design has about 10% greater effectiveness than manual control rod of the old design. (author)

  15. Use of Supplemental Short Pre-Contoured Accessory Rods and Cobalt Chrome Alloy Posterior Rods Reduces Primary Rod Strain and Range of Motion Across the Pedicle Subtraction Osteotomy Level: An In Vitro Biomechanical Study.

    Science.gov (United States)

    Hallager, Dennis Winge; Gehrchen, Martin; Dahl, Benny; Harris, Jonathan A; Gudipally, Manasa; Jenkins, Sean; Wu, Ai-Min; Bucklen, Brandon S

    2016-04-01

    In vitro cadaveric biomechanical study. To assess effects of 4-rod reconstruction, rod material, and anterior column support on motion and surface rod strain in a pedicle subtraction osteotomy model. Pedicle subtraction osteotomy (PSO) can correct significant sagittal deformity of the lumbar spine; however, revision rates are high. To reduce rod strain and the incidence of rod fracture, clinical use of multi-rod construction, cobalt chrome (CoCr) alloy rods, and interbody spacers adjacent to PSO has been proposed. Investigating both motion and rod strain is necessary to determine the biomechanical efficacy of these techniques. Five specimens (T12-S1) underwent PSO at L3 with pedicle screw stabilization at L1-S1. Pedicle subtraction was adjusted to achieve a final lordosis of 70°. Flexion-extension (FE), lateral bending, and axial rotation were applied. Linear strain gauges measured surface rod strain during FE on primary and accessory rods at PSO level. Testing evaluated (1) accessory rods (4-Rod) added at PSO level versus primary rods (2-Rod); (2) Ti versus CoCr rods; and (3) lateral interbody spacers (S) inserted adjacent to PSO. One-way and three-way analysis of variance was performed (P ≤ 0.05). All constructs significantly reduced FE and lateral bending motion relative to intact (P < 0.001). The main effect of accessory rods in reducing FE motion was significant (P = 0.021). Accessory and CoCr rods reduced relative surface strain on the primary rod, irrespective of construct (P < 0.001). CoCr 4-Rod + S provided the greatest reduction in strain (76% decrease; P = 0.003). Accessory and CoCr rods provided greatest reduction in motion and rod strain at PSO level. Interbody devices minimally affected motion-induced strain and might act primarily to maintain disc height. Clinicians must assess whether surface strain and motion reduction minimize the incidence of rod fracture. N/A.

  16. Fuel rod failure due to marked diametral expansion and fuel rod collapse occurred in the HBWR power ramp experiment

    International Nuclear Information System (INIS)

    Yanagisawa, Kazuaki

    1985-12-01

    In the power ramp experiment with the BWR type light water loop at the HBWR, the two pre-irradiated fuel rods caused an unexpected pellet-cladding interaction (PCI). One occurred in the fuel rod with small gap of 0.10 mm, which was pre-irradiated up to the burn-up of 14 MWd/kgU. At high power, the diameter of the rod was increased markedly without accompanying significant axial elongation. The other occurred in the rod with a large gap of 0.23 mm, which was pre-irradiated up to the burn-up of 8 MWd/kgU. The diameter of the rod collapsed during a diameter measurement at the maximum power level. The causes of those were investigated in the present study by evaluating in-core data obtained from equipped instruments in the experiment. It was revealed from the investigation that these behaviours were attributed to the local reduction of the coolant flow occurred in the region of a transformer in the ramp rig. The fuel cladding material is seemed to become softened due to temperature increase caused by the local reduction of the coolant flow, and collapsed by the coolant pressure, either locally or wholly depending on the rod diametral gap existed. (author)

  17. Modifications in Glass Ionomer Cements: Nano-Sized Fillers and Bioactive Nanoceramics

    Science.gov (United States)

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Khan, Abdul Samad; Zohaib, Sana; Martí, Juan Manuel Nuñez; Sauro, Salvatore; Matinlinna, Jukka Pekka; Rehman, Ihtesham Ur

    2016-01-01

    Glass ionomer cements (GICs) are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs) can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the set matrix, apatites can make the set cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties. PMID:27428956

  18. Constrained Geometry Organotitanium Catalysts Supported on Nanosized Silica for Ethylene (co)Polymerization.

    Science.gov (United States)

    Li, Kuo-Tseng; Wu, Ling-Huey

    2017-05-05

    Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This study aims to improve the activity of supported CGC catalysts by using nanometer-sized silica. Ti[(C₅Me₄)SiMe₂(N t Bu)]Cl₂, a "constrained-geometry" titanium catalyst, was supported on MAO-treated silicas (nano-sized and micro-sized) by an impregnation method. Ethylene homo-polymerization and co-polymerization with 1-octene were carried out in a temperature range of 80-120 °C using toluene as the solvent. Catalysts prepared and polymers produced were characterized. For both catalysts and for both reactions, the maximum activities occurred at 100 °C, which is significantly higher than that (60 °C) reported before for supported bis-cyclopentadienyl metallocene catalysts containing zirconium, and is lower than that (≥140 °C) used for unsupported Ti[(C₅Me₄)SiMe₂(N t Bu)]Me₂ catalyst. Activities of nano-sized catalyst were 2.6 and 1.6 times those of micro-sized catalyst for homopolymerization and copolymerization, respectively. The former produced polymers with higher crystallinity and melting point than the latter. In addition, copolymer produced with nanosized catalyst contained more 1-octene than that produced with microsized catalyst.

  19. Nano-sized cosmetic formulations or solid nanoparticles in sunscreens: a risk to human health?

    Science.gov (United States)

    Nohynek, Gerhard J; Dufour, Eric K

    2012-07-01

    Personal care products (PCP) often contain micron- or nano-sized formulation components, such as nanoemulsions or microscopic vesicles. A large number of studies suggest that such vesicles do not penetrate human skin beyond the superficial layers of the stratum corneum. Nano-sized PCP formulations may enhance or reduce skin absorption of ingredients, albeit at a limited scale. Modern sunscreens contain insoluble titanium dioxide (TiO₂) or zinc oxide (ZnO) nanoparticles (NP), which are efficient filters of UV light. A large number of studies suggest that insoluble NP do not penetrate into or through human skin. A number of in vivo toxicity tests, including in vivo intravenous studies, showed that TiO₂ and ZnO NP are non-toxic and have an excellent skin tolerance. Cytotoxicity, genotoxicity, photo-genotoxicity, general toxicity and carcinogenicity studies on TiO₂ and ZnO NP found no difference in the safety profile of micro- or nano-sized materials, all of which were found to be non-toxic. Although some published in vitro studies on insoluble nano- or micron-sized particles suggested cell uptake, oxidative cell damage or genotoxicity, these data are consistent with those from micron-sized particles and should be interpreted with caution. Data on insoluble NP, such as surgical implant-derived wear debris particles or intravenously administered magnetic resonance contrast agents suggest that toxicity of small particles is generally related to their chemistry rather than their particle size. Overall, the weight of scientific evidence suggests that insoluble NP used in sunscreens pose no or negligible risk to human health, but offer large health benefits, such as the protection of human skin against UV-induced skin ageing and cancer.

  20. Fed-batch production of the hydrophobins RodA and RodB from Aspergillus fumigatus in host Pichia pastoris

    DEFF Research Database (Denmark)

    Pedersen, Mona Højgaard; Borodina, Irina; Frisvad, Jens Christian

    Objectives: Aspergillus fumigatus expresses the hydrophobins RodA and RodB on the surface of its conidia. RodA is known to be important for the pathogenesis of the fungus, but the role of RodB is unknown. The aim was to produce recombinant RodA and RodB for further characterication. Methods....... The expression of the RodA and RodB genes was first studied in culture flasks in buffered complex methanol medium as protein production was dependent on the methanol-induced AOX1 promoter. Later production was scaled up to a 2 L fed-batch fermentor. Hydrophobins were purified using His-select Nickel Affinity gel...

  1. Silicon-based photocells of enhanced spectral sensitivity with nano-sized graded band gap structures

    International Nuclear Information System (INIS)

    Bakhadyrkhanov, M.K.; Isamov, S.B.; Iliev, K.M. et al.

    2014-01-01

    Photoelectric properties of monocrystalline silicon with multiply charged nanoclusters are studied that generate 'silicon clusters', i.e., nano-sized graded band gap structures. Multiply charged nanoclusters of manganese atoms strongly influence the photoelectric properties of monocrystalline silicon and expand the range of spectral sensitivity up to 8 μm; the photoelectric sensitivity reaches ∼10 9 . Conditions occur for the emergence of photo-emf in such a material in the infrared region when hν< E g . The obtained experimental data expand the functional capabilities for the application of silicon with multiply charged impurity atoms. (authors)

  2. Structure of extremely nanosized and confined In-O species in ordered porous materials

    International Nuclear Information System (INIS)

    Ramallo-Lopez, J.M.; Renteria, M.; Miro, E.E.; Requejo, F.G.; Traverse, A.

    2003-01-01

    Perturbed-angular correlation, x-ray absorption, and small-angle x-ray scattering spectroscopies were suitably combined to elucidate the local structure of highly diluted and dispersed InO x species confined in the porous of the ZSM5 zeolite. This novel approach allow us to determined the structure of extremely nanosized In-O species exchanged inside the 10-atom-ring channel of the zeolite, and to quantify the amount of In 2 O 3 crystallites deposited onto the external zeolite surface

  3. Identification and characterization of the nano-sized vesicles released by muscle cells.

    Science.gov (United States)

    Romancino, Daniele P; Paterniti, Gaetano; Campos, Yvan; De Luca, Angela; Di Felice, Valentina; d'Azzo, Alessandra; Bongiovanni, Antonella

    2013-05-02

    Several cell types secrete small membranous vesicles that contain cell-specific collections of proteins, lipids, and genetic material. The function of these vesicles is to allow cell-to-cell signaling and the horizontal transfer of their cargo molecules. Here, we demonstrate that muscle cells secrete nano-sized vesicles and that their release increases during muscle differentiation. Analysis of these nanovesicles allowed us to characterize them as exosome-like particles and to define the potential role of the multifunctional protein Alix in their biogenesis. Copyright © 2013 Federation of European Biochemical Societies. All rights reserved.

  4. Thermodynamics of disaggregated polymer composites based on nanosized powders of Ni and NiO

    Directory of Open Access Journals (Sweden)

    N. S. Volodina

    2015-03-01

    Full Text Available Technique to obtain disaggregated composites with uniform distribution of the Ni nanoparticles in a polymer matrix was developed on the example of epoxy resin. Disaggregated and aggregated composites based on butyl methacrylate copolymer with 5 wt% methacrylic acid and Ni and NiO nanoparticles were obtained. Enthalpies of mixing the components compositions in a wide range of compositions were defined using isothermal calorimetry. Parameters adhesive interaction at the interface and glassy polymer structure changes were calculated. The influence of the chemical nature of nanosized filler on interfacial energy was found.

  5. Nanoscale Design of Nano-Sized Particles in Shape-Memory Polymer Nanocomposites Driven by Electricity

    Directory of Open Access Journals (Sweden)

    Kai Yu

    2013-09-01

    Full Text Available In the last few years, we have witnessed significant progress in developing high performance shape memory polymer (SMP nanocomposites, in particular, for shape recovery activated by indirect heating in the presence of electricity, magnetism, light, radio frequency, microwave and radiation, etc. In this paper, we critically review recent findings in Joule heating of SMP nanocomposites incorporated with nanosized conductive electromagnetic particles by means of nanoscale control via applying an electro- and/or magnetic field. A few different nanoscale design principles to form one-/two-/three- dimensional conductive networks are discussed.

  6. Synthesis of nano-sized β-tricalcium phosphate via wet precipitation

    Directory of Open Access Journals (Sweden)

    Bahman Mirhadi

    2011-12-01

    Full Text Available Nano-size β-tricalcium phosphate powders with average grain size of 50 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The pH of the system was maintained at 8 and 10.8 by adding of sodium hydroxide. Filtered cake was dried at 80°C and calcined at 700°C. The dried and calcined powders were characterized using X-ray diffractrometry (XRD, Fourier transform infrared spectroscopy (FTIR, inductively coupled plasma atomic emission spectroscopy (ICPAES and scanning electron microscopy (SEM.

  7. Mechanical properties of silicone composites reinforced with micron- and nano-sized magnetic particles

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2013-06-01

    Full Text Available Silicone composites filled with different-sized nickel particles were prepared. By applying a permanent magnet, both the micron- and nano-sized particles were found to distribute along the magnetic field direction, resulting in chain-like microstructures, which improved the key mechanical properties of the resultant samples effectively, compared to the samples with randomly-distributed particles. The composites were also tested under various magnetic field strengths. The samples with aligned particles showed larger improvements in shear storage modulus than those with random particles.

  8. Estimation of rod scale errors in geodetic leveling

    Science.gov (United States)

    Craymer, Michael R.; Vaníček, Petr; Castle, Robert O.

    1995-01-01

    Comparisons among repeated geodetic levelings have often been used for detecting and estimating residual rod scale errors in leveled heights. Individual rod-pair scale errors are estimated by a two-step procedure using a model based on either differences in heights, differences in section height differences, or differences in section tilts. It is shown that the estimated rod-pair scale errors derived from each model are identical only when the data are correctly weighted, and the mathematical correlations are accounted for in the model based on heights. Analyses based on simple regressions of changes in height versus height can easily lead to incorrect conclusions. We also show that the statistically estimated scale errors are not a simple function of height, height difference, or tilt. The models are valid only when terrain slope is constant over adjacent pairs of setups (i.e., smoothly varying terrain). In order to discriminate between rod scale errors and vertical displacements due to crustal motion, the individual rod-pairs should be used in more than one leveling, preferably in areas of contrasting tectonic activity. From an analysis of 37 separately calibrated rod-pairs used in 55 levelings in southern California, we found eight statistically significant coefficients that could be reasonably attributed to rod scale errors, only one of which was larger than the expected random error in the applied calibration-based scale correction. However, significant differences with other independent checks indicate that caution should be exercised before accepting these results as evidence of scale error. Further refinements of the technique are clearly needed if the results are to be routinely applied in practice.

  9. Control Rod Driveline Reactivity Feedback Model for Liquid Metal Reactors

    International Nuclear Information System (INIS)

    Kwon, Young-Min; Jeong, Hae-Yong; Chang, Won-Pyo; Cho, Chung-Ho; Lee, Yong-Bum

    2008-01-01

    The thermal expansion of the control rod drivelines (CRDL) is one important passive mitigator under all unprotected accident conditions in the metal and oxide cores. When the CRDL are washed by hot sodium in the coolant outlet plenum, the CRDL thermally expands and causes the control rods to be inserted further down into the active core region, providing a negative reactivity feedback. Since the control rods are attached to the top of the vessel head and the core attaches to the bottom of the reactor vessel (RV), the expansion of the vessel wall as it heats will either lower the core or raise the control rods supports. This contrary thermal expansion of the reactor vessel wall pulls the control rods out of the core somewhat, providing a positive reactivity feedback. However this is not a safety factor early in a transient because its time constant is relatively large. The total elongated length is calculated by subtracting the vessel expansion from the CRDL expansion to determine the net control rod expansion into the core. The system-wide safety analysis code SSC-K includes the CRDL/RV reactivity feedback model in which control rod and vessel expansions are calculated using single-nod temperatures for the vessel and CRDL masses. The KALIMER design has the upper internal structures (UIS) in which the CRDLs are positioned outside the structure where they are exposed to the mixed sodium temperature exiting the core. A new method to determine the CRDL expansion is suggested. Two dimensional hot pool thermal hydraulic model (HP2D) originally developed for the analysis of the stratification phenomena in the hot pool is utilized for a detailed heat transfer between the CRDL mass and the hot pool coolant. However, the reactor vessel wall temperature is still calculated by a simple lumped model

  10. Mechanical properties of dental composite materials reinforced with micro and nano-size Al2O3 filler particles

    International Nuclear Information System (INIS)

    Foroutan, F.; Javadpour, J.; Khavandi, A.; Atai, M.

    2011-01-01

    Composite specimens were prepared by dispersion of various amounts of nano-sized Al 2 O 3 fillers in a monomer system containing 60 p ercent B is-GMA and 40 p ercent T EGDMA. For comparative purposes, composite samples containing micrometer size Al 2 O 3 fillers were also prepared following the same procedure. The mechanical properties of the light- cured samples were assessed by three-point flexural strength, diametral tensile strength, and microhardness tests. The results indicated a more than hundred percent increase in the flexural strength and nearly an eighty percent increase in the diametral tensile strength values in the samples containing nano-size Al 2 O 3 filler particles. It is interesting to note that, this improvement was observed at a much lower nano-size filler content. Fracture surfaces analyzed by scanning electron microscopy, indicated a brittle type of fracture in both sets of specimens.

  11. Strategy for Fuel Rod Receipt, Characterization, Sample Allocation for the Demonstration Sister Rods

    Energy Technology Data Exchange (ETDEWEB)

    Marschman, Steven C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Warmann, Stephan A. [Portage, Inc., Idaho Falls, ID (United States); Rusch, Chris [NAC International, Inc., Norcross, GA (United States)

    2014-03-01

    , inert gas backfilling, and transfer to an Independent Spent Fuel Storage Installation (ISFSI) for multi-year storage. To document the initial condition of the used fuel prior to emplacement in a storage system, “sister ” fuel rods will be harvested and sent to a national laboratory for characterization and archival purposes. This report supports the demonstration by describing how sister rods will be shipped and received at a national laboratory, and recommending basic nondestructive and destructive analyses to assure the fuel rods are adequately characterized for UFDC work. For this report, a hub-and-spoke model is proposed, with one location serving as the hub for fuel rod receipt and characterization. In this model, fuel and/or clad would be sent to other locations when capabilities at the hub were inadequate or nonexistent. This model has been proposed to reduce DOE-NE’s obligation for waste cleanup and decontamination of equipment.

  12. Presence of nano-sized silica during in vitro digestion of foods containing silica as a food additive.

    Science.gov (United States)

    Peters, Ruud; Kramer, Evelien; Oomen, Agnes G; Rivera, Zahira E Herrera; Oegema, Gerlof; Tromp, Peter C; Fokkink, Remco; Rietveld, Anton; Marvin, Hans J P; Weigel, Stefan; Peijnenburg, Ad A C M; Bouwmeester, Hans

    2012-03-27

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products subjected to in vitro digestion included (i) hot water, (ii) coffee with powdered creamer, (iii) instant soup, and (iv) pancake which either contained silica as the food additive E551, or to which a form of synthetic amorphous silica or 32 nm SiO(2) particles were added. The results showed that, in the mouth stage of the digestion, nano-sized silica particles with a size range of 5-50 and 50-500 nm were present in food products containing E551 or added synthetic amorphous silica. However, during the successive gastric digestion stage, this nano-sized silica was no longer present for the food matrices coffee and instant soup, while low amounts were found for pancakes. Additional experiments showed that the absence of nano-sized silica in the gastric stage can be contributed to an effect of low pH combined with high electrolyte concentrations in the gastric digestion stage. Large silica agglomerates are formed under these conditions as determined by DLS and SEM experiments and explained theoretically by the extended DLVO theory. Importantly, in the subsequent intestinal digestion stage, the nano-sized silica particles reappeared again, even in amounts higher than in the saliva (mouth) digestion stage. These findings suggest that, upon consumption of foods containing E551, the gut epithelium is most likely exposed to nano-sized silica. © 2012 American Chemical Society

  13. Nuclear Fuel Test Rod Fabrication for Data Acquisition Test

    International Nuclear Information System (INIS)

    Joung, Chang-Young; Hong, Jin-Tae; Kim, Ka-Hye; Huh, Sung-Ho

    2014-01-01

    A nuclear fuel test rod must be fabricated with precise welding and assembly technologies, and confirmed for their soundness. Recently, we have developed various kinds of processing systems such as an orbital TIG welding system, a fiber laser welding system, an automated drilling system and a helium leak analyzer, which are able to fabricate the nuclear fuel test rods and rigs, and keep inspection systems to confirm the soundness of the nuclear fuel test rods and rids. The orbital TIG welding system can be used with two kinds of welding methods. One can perform the round welding for end-caps of a nuclear fuel test rod by an orbital head mounted in a low-pressure chamber. The other can do spot welding for a pin-hole of a nuclear fuel test rod in a high-pressure chamber to fill up helium gas of high pressure. The fiber laser welding system can weld cylindrical and 3 axis samples such as parts of a nuclear fuel test rod and instrumentation sensors which is moved by an index chuck and a 3 axis (X, Y, Z) servo stage controlled by the CNC program. To measure the real-time temperature change at the center of the nuclear fuel during the irradiation test, a thermocouple should be instrumented at that position. Therefore, a hole needs to be made at the center of fuel pellet to instrument the thermocouple. An automated drilling system can drill a fine hole into a fuel pellet without changing tools or breaking the work-piece. The helium leak analyzer (ASM-380 model of DEIXEN Co.) can check the leak of the nuclear fuel test rod filled with helium gas. This paper describes not only the assembly and fabrication methods used by the process systems, but also the results of the data acquisition test for the nuclear fuel test rod. A nuclear fuel test rod for the data acquisition test was fabricated using the welding and assembling echnologies acquired from previous tests

  14. Analysis of Explanted Magnetically Controlled Growing Rods From Seven UK Spinal Centers.

    Science.gov (United States)

    Joyce, Thomas J; Smith, Simon L; Rushton, Paul R P; Bowey, Andrew J; Gibson, Michael J

    2018-01-01

    Analysis of explanted MAGnetic Expansion Control (MAGEC) growing rods. To analyze explanted MAGEC rods used in management of early onset scoliosis and identify the mode of failure in such cases. Magnetically controlled growing rods are increasingly used as the option of choice for early onset scoliosis. However, being more complex than conventional growing rods they are perhaps more likely to succumb to multifarious failure modes. In addition, metallosis has been reported around failed MAGEC rods. Explanted MAGEC rods from seven UK spinal centers were obtained for independent analysis. Thirty-four MAGEC rods, from 18 children, explanted for reasons including failure of rod lengthening and maximum rod distraction reached, were cut open to allow internal components to be evaluated and assessed. Externally, all MAGEC rods showed localized marks, which were termed "growth marks" as they indicated growth of the rod in vivo, on the extending bar component. After cutting open, titanium wear debris was found inside all 34 (100%) MAGEC rods. Ninety-one percent (31/34) of MAGEC rods showed measurable wear of the extending bar, towards the magnet end. Substantial damage to the radial bearing was seen inside 74% (25/34) of MAGEC rods while O-ring seal failure was seen in 53% (18/34) of cases. In 44% (15/34) of MAGEC rods the drive pin was fractured but this was felt to be an effect of rod failure, not a cause. The combination of high volumes of titanium wear debris alongside O-ring seal damage likely accounts for the metallosis reported clinically around some MAGEC rods. Based on this explant data, a failure mechanism in MAGEC rods due to the natural off axis loading in the spine was proposed. This is the largest data set reporting a complete analysis of explanted MAGEC rods to date. 4.

  15. Controlling a nuclear reactor with dropped control rods

    International Nuclear Information System (INIS)

    Mc Atee, K.R.; Alsop, B.H.

    1987-01-01

    A control system is described for a nuclear power plant including a reactor with a core having an upper portion and a lower portion and control rods which are inserted into and withdrawn from the core of the reactor vertically to control reactivity in the core. The system comprises: means to measure neutron flux separately in the upper portion and the lower portion of the reactor and to generate from such measurements a signal representative of axial distribution of power between the upper and lower portions of the reactor core; means to detect a dropped control rod in the reactor and to generate a dropped rod signal in response thereto; means to generate an axial power distribution limit signal representative of a critical axial power distribution for a dropped rod condition; means to compare the axial power distribution signal to the axial power distribution limit signal and to generate an axial power distribution out of limits signal when the axial power distribution signal exceeds the axial power distribution limit signal; and means responsive only to the presence of both the dropped rod signal and the axial power distribution out of limits signal to generate a signal for shutting the reactor down

  16. Fuel rod design by statistical methods for MOX fuel

    International Nuclear Information System (INIS)

    Heins, L.; Landskron, H.

    2000-01-01

    Statistical methods in fuel rod design have received more and more attention during the last years. One of different possible ways to use statistical methods in fuel rod design can be described as follows: Monte Carlo calculations are performed using the fuel rod code CARO. For each run with CARO, the set of input data is modified: parameters describing the design of the fuel rod (geometrical data, density etc.) and modeling parameters are randomly selected according to their individual distributions. Power histories are varied systematically in a way that each power history of the relevant core management calculation is represented in the Monte Carlo calculations with equal frequency. The frequency distributions of the results as rod internal pressure and cladding strain which are generated by the Monte Carlo calculation are evaluated and compared with the design criteria. Up to now, this methodology has been applied to licensing calculations for PWRs and BWRs, UO 2 and MOX fuel, in 3 countries. Especially for the insertion of MOX fuel resulting in power histories with relatively high linear heat generation rates at higher burnup, the statistical methodology is an appropriate approach to demonstrate the compliance of licensing requirements. (author)

  17. Device and method of cooling control rod drives

    International Nuclear Information System (INIS)

    Togashi, Hidetoshi; Mase, Noriaki; Matsumura, Yuichi.

    1985-01-01

    Purpose: To prevent the generation of local temperature rise depending on the reactor core position of the control rod drives and control the temperature to an averaged state in BWR type reactors. Method: Control rod drives having a large charging length of the housing in the pressure vessel involve such a factor that the temperature of the control rod drives is increased by the synergistic effect due to the radiation heat from the reactor core and to the unevenness of the cooling water flow rate, which renders an appropriate temperature control difficult for the reactor core position. A cooling water flow rate controlling device having a restriction mechanism is disposed on the cooling water feed path for each of the hydraulic control units of the control rod drives, so that flow rate to the control rod drives is increased at the center of the reactor core and decreased at the periphery thereof. As a result, average temperature state can be set, temperature increase due to cloggings can be prevented and the thermal effect can be eliminated to thereby improve the reliability. (Moriyama, K.)

  18. Failed fuel rod detection system and computerized manipulator during outages

    International Nuclear Information System (INIS)

    Boehm, H.H.; Foerch, H.

    1984-01-01

    During regular outages spent fuel assemblies need to be replaced and relocated within the core. Defective fuel rods in particular fuel assemblies have to be removed from further service and before delivery of such faulty fuel assemblies to a reprocessing plant. The system which Brown Boveri Reaktor GmbH and Krautkraemer have developed in the Federal Republic of Germany is capable of directly locating the defective rods in a proper fuel assembly. Inspection times are comparable to those of standard sipping methods, with the advantages of immediately available results and direct identification of the defective fuel rods. During the repair of fuel assemblies this system allows withdrawal of individual defective rods. With the sipping method all the fuel rods of a defective fuel assembly need to be removed and inspected by eddy current testing. During steam generator inspection and repair personnel are exposed to ample radiation. A remotely controlled, computerized manipulator was used to significantly reduce the radiation dose by automating steps in the procedures; at the same time inspection and repair times were reduced. The main features of the manipulator are a rigid component construction of the leg and two arms, and a resolver control for horizontal and vertical motion that enables rapid and accurate access to a desired tube (author)

  19. The graphic model of the spent fuel rod extracting system

    International Nuclear Information System (INIS)

    Yoon, Jee Sup; Kim, Sung Hyun

    1997-01-01

    The spent fuel rod extracting system is being developed in KAERI to deal with problems associated with utilization of storage pools at nuclear power plants. This system consists of an equipment system for extracting rods from spent fuel assemblies, a machine controller, and a supervisory controller. The performance of extraction system has been investigated through a series of experiments. Even though the system is designed to automatically perform sequential procedures, several problems have been found such as the gripper stucking to fuel rod caused by misaligned positioning and the socket jamming of impact wrench into the nut, etc. Up to this end the graphical model of the rod extracting system has been made so that possible sequences of operations including error detection and recovery actions are verified by using a graphic simulation before real operations. For the implementation, IGRIP is being used as a multifunctional tool for developing the rod extraction system. IGRIP is not only an excellent visualization tool, but it also highlights modeling virtual machine. (author). 6 refs., 1 tab., 6 figs

  20. Substitute safety rods: Physics of operation and irradiation

    International Nuclear Information System (INIS)

    Baumann, N.P.

    1991-01-01

    Under certain assumed accidents, an SRS reactor may lose most of its bulk moderator while maintaining flow to fuel assemblies. If this occurs immediately after operation at power, components normally dependent on convective heat transfer to the moderator will heat up with the possibility of melting that component. One component at risk is the currently used cadmium safety rod. A substitute safety rod consisting solely of sintered B 4 C and stainless steel has been designed which is capable of withstanding much higher temperatures. This memorandum provides the physics basis for the adequacy of the rod for reactor shutdown and provides a set of criteria for acceptance in the NTG tests. This memorandum provides physics data for other aspects of operation. These include: Heat production and helium production, along with related phenomena, resulting from inadvertent irradiation at power. Gamma heat input under drained tank conditions. An equivalent rod design suitable for charge design and safety analyses. Degradation under normal operation. Thermal flux ripple in adjacent fuel due to axial striping of alternate B 4 C and steel pellets. Possible effect on safety analyses. Safety rod withdrawal during reactor startup

  1. Plasmonic-cavity model for radiating nano-rod antennas

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the ......In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition...... and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide...... frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns....

  2. MD simulation analysis of resin filling into nano-sized pore formed on metal surface

    Science.gov (United States)

    Mori, Hodaka; Matubayasi, Nobuyuki

    2018-01-01

    All-atom MD simulation was conducted for the filling of epoxy resin into a nano-sized pore formed on aluminum surface. The resin species examined were polyphenol mixed with polyglycidylether of o-cresol formaldehyde novolac and their oligomers formed through ring-opening reactions. The degree of oligomerization was varied from 0.5 to 2.5 nm in terms of the radius of gyration, and the radius of the cylindrical pore was fixed at 2.5 nm. It was observed that a small resin penetrates into the pore along the wall, while larger resins move rather uniformly in the pore. The maximum density in the pore achieved with pushing was then seen to be larger when the resin is smaller. It was found that when the radius of gyration of resin is larger than half the pore radius, the resin density in the pore does not reach half the bulk density of the resin. This implies that the resin-resin interaction inhibits the filling of the nano-sized pore.

  3. Snow-borne nanosized particles: Abundance, distribution, composition, and significance in ice nucleation processes

    Science.gov (United States)

    Rangel-Alvarado, Rodrigo Benjamin; Nazarenko, Yevgen; Ariya, Parisa A.

    2015-11-01

    Physicochemical processes of nucleation constitute a major uncertainty in understanding aerosol-cloud interactions. To improve the knowledge of the ice nucleation process, we characterized physical, chemical, and biological properties of fresh snow using a suite of state-of-the-art techniques based on mass spectrometry, electron microscopy, chromatography, and optical particle sizing. Samples were collected at two North American Arctic sites, as part of international campaigns (2006 and 2009), and in the city of Montreal, Canada, over the last decade. Particle size distribution analyses, in the range of 3 nm to 10 µm, showed that nanosized particles are the most numerous (38-71%) in fresh snow, with a significant portion (11 to 19%) less than 100 nm in size. Particles with diameters less than 200 nm consistently exhibited relatively high ice-nucleating properties (on average ranged from -19.6 ± 2.4 to -8.1 ± 2.6°C). Chemical analysis of the nanosized fraction suggests that they contain bioorganic materials, such as amino acids, as well as inorganic compounds with similar characteristics to mineral dust. The implication of nanoparticle ubiquity and abundance in diverse snow ecosystems are discussed in the context of their importance in understanding atmospheric nucleation processes.

  4. A new nano-sized iron oxide particle with high sensitivity for cellular magnetic resonance imaging.

    Science.gov (United States)

    Chen, Chih-Lung; Zhang, Haosen; Ye, Qing; Hsieh, Wen-Yuan; Hitchens, T Kevin; Shen, Hsin-Hsin; Liu, Li; Wu, Yi-Jen; Foley, Lesley M; Wang, Shian-Jy; Ho, Chien

    2011-10-01

    In this study, we investigated the labeling efficiency and magnetic resonance imaging (MRI) signal sensitivity of a newly synthesized, nano-sized iron oxide particle (IOP) coated with polyethylene glycol (PEG), designed by Industrial Technology Research Institute (ITRI). Macrophages, bone-marrow-derived dendritic cells, and mesenchymal stem cells (MSCs) were isolated from rats and labeled by incubating with ITRI-IOP, along with three other iron oxide particles in different sizes and coatings as reference. These labeled cells were characterized with transmission electron microscopy (TEM), light and fluorescence microscopy, phantom MRI, and finally in vivo MRI and ex vivo magnetic resonance microscopy (MRM) of transplanted hearts in rats infused with labeled macrophages. The longitudinal (r (1)) and transverse (r (2)) relaxivities of ITRI-IOP are 22.71 and 319.2 s(-1) mM(-1), respectively. TEM and microscopic images indicate the uptake of multiple ITRI-IOP particles per cell for all cell types. ITRI-IOP provides sensitivity comparable or higher than the other three particles shown in phantom MRI. In vivo MRI and ex vivo MRM detect punctate spots of hypointensity in rejecting hearts, most likely caused by the accumulation of macrophages labeled by ITRI-IOP. ITRI-IOP, the nano-sized iron oxide particle, shows high efficiency in cell labeling, including both phagocytic and non-phagocytic cells. Furthermore, it provides excellent sensitivity in T(2)*-weighted MRI, and thus can serve as a promising contrast agent for in vivo cellular MRI.

  5. Vaccine delivery system for tuberculosis based on nano-sized hepatitis B virus core protein particles.

    Science.gov (United States)

    Dhanasooraj, Dhananjayan; Kumar, R Ajay; Mundayoor, Sathish

    2013-01-01

    Nano-sized hepatitis B virus core virus-like particles (HBc-VLP) are suitable for uptake by antigen-presenting cells. Mycobacterium tuberculosis antigen culture filtrate protein 10 (CFP-10) is an important vaccine candidate against tuberculosis. The purified antigen shows low immune response without adjuvant and tends to have low protective efficacy. The present study is based on the assumption that expression of these proteins on HBc nanoparticles would provide higher protection when compared to the native antigen alone. The cfp-10 gene was expressed as a fusion on the major immunodominant region of HBc-VLP, and the immune response in Balb/c mice was studied and compared to pure proteins, a mixture of antigens, and fusion protein-VLP, all without using any adjuvant. The humoral, cytokine, and splenocyte cell proliferation responses suggested that the HBc-VLP bearing CFP-10 generated an antigen-specific immune response in a Th1-dependent manner. By virtue of its self-adjuvant nature and ability to form nano-sized particles, HBc-VLPs are an excellent vaccine delivery system for use with subunit protein antigens identified in the course of recent vaccine research.

  6. Possible role of nano-sized particles in chronic tonsillitis and tonsillar carcinoma: a pilot study.

    Science.gov (United States)

    Zeleník, Karol; Kukutschová, Jana; Dvořáčková, Jana; Bielniková, Hana; Peikertová, Pavlína; Cábalová, Lenka; Komínek, Pavel

    2013-02-01

    This study aimed to evaluate the palatine tonsils of patients with chronic tonsillitis and spinocellular carcinoma to determine the presence of nano-sized particles. Tonsil samples from adult patients with chronic tonsillitis and spinocellular carcinoma of the palatine tonsil were dried and analyzed using a scanning electron microscope with the X-ray microprobe of an energy-dispersive spectroscope. Demographic data and smoking histories were obtained. The principal metals found in almost all tissues analyzed were iron, chromium, nickel, aluminum, zinc, and copper. No significant difference in elemental composition was found between the group of patients with chronic tonsillitis and the group with spinocellular carcinoma of the palatine tonsil. Likewise, no significant difference was found between the group of smokers and the group of nonsmokers. The presence of various micro- and nano-sized metallic particles in human tonsils was confirmed. These particles may potentially cause an inflammatory response as well as neoplastic changes in human palatine tonsils similar to those occurring in the lungs. Further and more detailed studies addressing this issue, including studies designed to determine the chemical form of the metals detected, studies devoted to quantitative analysis, biokinetics, and to the degradation and elimination of nanoparticles are needed for a more detailed prediction of the relation between the diagnosis and the presence of specific metal nanoparticles in tonsillar tissue.

  7. Structure of Nano-sized CeO2 Materials: Combined Scattering and Spectroscopic Investigations.

    Science.gov (United States)

    Marchbank, Huw R; Clark, Adam H; Hyde, Timothy I; Playford, Helen Y; Tucker, Matthew G; Thompsett, David; Fisher, Janet M; Chapman, Karena W; Beyer, Kevin A; Monte, Manuel; Longo, Alessandro; Sankar, Gopinathan

    2016-11-04

    The structure of several nano-sized ceria, CeO 2 , systems was investigated using neutron and X-ray diffraction and X-ray absorption spectroscopy. Whilst both diffraction and total pair distribution functions (PDFs) revealed that in all of the samples the occupancy of both Ce 4+ and O 2- are very close to the ideal stoichiometry, the analysis using Reverse Monte Carlo technique revealed significant disorder around oxygen atoms in the nano-sized ceria samples in comparison to the highly crystalline NIST standard. In addition, the analysis revealed that the main differences observed in the pair correlations from various X-ray and neutron diffraction techniques were attributable to the particle size of the CeO 2 prepared by the reported three methods. Furthermore, detailed analysis of the Ce L 3 - and K-edge EXAFS data support this finding; in particular the decrease in higher shell coordination numbers with respect to the NIST standard, is attributed to differences in particle size. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Mixing and Characterization of Nanosized Powders: An Assessment of Different Techniques

    International Nuclear Information System (INIS)

    Wei Dongguang; Dave, Rajesh; Pfeffer, Robert

    2002-01-01

    The objective of this paper was to gain an understanding of the mixing and characterization of nanosized powders. Three different nanosized material systems were selected based on their physical and chemical properties. Mixing experiments of the selected nanopowders were performed using a variety of environmentally friendly dry powder processing devices and the rapid expansion of supercritical CO 2 suspensions (RESS process) and compared with solvent-based methods coupled with ultrasonic agitation. A number of imaging techniques, including FESEM, AFM, TEM, EELS and EDS were used to characterize the degree of mixing or homogeneity of the mixtures obtained.The results indicate that only some of the imaging techniques are capable of determining the quality of nanoparticle mixing, depending on the physical and chemical properties of the nanopowders. For example, field emission scanning electron microscope (FESEM) is suitable for characterizing powder mixtures having a distinct difference in particle shape, or with a large difference in atomic number of the metallic element of the two constituents. Only electron energy loss spectroscopy (EELS) was able to fully characterize nanopowder mixtures of SiO 2 and TiO 2 at the nanoscale. Energy dispersive X-ray spectroscopy (EDS) provided information on mixing quality, but only on a scale of about 1 μm. The results also show that solvent-based mixing methods coupled with ultrasonic agitation, and RESS generally perform better than dry powder processing systems, with the exception of the hybridizer, in generating a homogeneous mixture

  9. Heavy metal removal from water/wastewater by nanosized metal oxides: a review.

    Science.gov (United States)

    Hua, Ming; Zhang, Shujuan; Pan, Bingcai; Zhang, Weiming; Lv, Lu; Zhang, Quanxing

    2012-04-15

    Nanosized metal oxides (NMOs), including nanosized ferric oxides, manganese oxides, aluminum oxides, titanium oxides, magnesium oxides and cerium oxides, provide high surface area and specific affinity for heavy metal adsorption from aqueous systems. To date, it has become a hot topic to develop new technologies to synthesize NMOs, to evaluate their removal of heavy metals under varying experimental conditions, to reveal the underlying mechanism responsible for metal removal based on modern analytical techniques (XAS, ATR-FT-IR, NMR, etc.) or mathematical models, and to develop metal oxide-based materials of better applicability for practical use (such as granular oxides or composite materials). The present review mainly focuses on NMOs' preparation, their physicochemical properties, adsorption characteristics and mechanism, as well as their application in heavy metal removal. In addition, porous host supported NMOs are particularly concerned because of their great advantages for practical application as compared to the original NMOs. Also, some magnetic NMOs were included due to their unique separation performance. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Synthesis, Characterization, and Magnetic Properties of Pure and EDTA-Capped NiO Nanosized Particles

    Directory of Open Access Journals (Sweden)

    H. T. Rahal

    2017-01-01

    Full Text Available The effect of ethylenediaminetetraacetic acid (EDTA as a capping agent on the structure, morphology, optical, and magnetic properties of nickel oxide (NiO nanosized particles, synthesized by coprecipitation method, was investigated. Nickel chloride hexahydrate and sodium hydroxide (NaOH were used as precursors. The resultant nanoparticles were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, and scanning electron microscopy (SEM. XRD patterns showed that NiO have a face-centered cubic (FCC structure. The crystallite size, estimated by Scherrer formula, has been found in the range of 28–33 nm. It is noticed that EDTA-capped NiO nanoparticles have a smaller size than pure nanoparticles. Thus, the addition of 0.1 M capping agent EDTA can form a nucleation point for nanoparticles growth. The optical and magnetic properties were investigated by Fourier transform infrared spectroscopy (FTIR and UV-vis absorption spectroscopy (UV as well as electron paramagnetic resonance (EPR and magnetization measurements. FTIR spectra indicated the presence of absorption bands in the range of 402–425 cm−1, which is a common feature of NiO. EPR for NiO nanosized particles was measured at room temperature. An EPR line with g factor ≈1.9–2 is detected for NiO nanoparticles, corresponding to Ni2+ ions. The magnetic hysteresis of NiO nanoparticles showed that EDTA capping recovers the surface magnetization of the nanoparticles.

  11. Fault pseudotachylyte: a coseismic lightning rod

    Science.gov (United States)

    Ferre, E. C.; Conder, J. A.; MathanaSekaran, N.; Geissman, J. W.

    2013-12-01

    of melt during the formation of a pseudotachylite vein. The increase in melt temperature is the most important factor affecting electrical conductivity in the fault plane. When the melt temperature rises from 1300 to 2000K, its electrical conductivity increases about 80 times. This implies that once a continuous pseudotachylite sheet-like vein is formed during an earthquake, the vein has a much higher electrical conductivity than its host-rock. The dramatic increase in electrical conductivity along the pseudotachylite plane might be synchronous with the generation of the coseismic electrical current. Thus, regardless of its origin, any electrical current produced during an earthquake will travel along the pseudotachylite plane which acts as a lightning rod. The magnetization of a solid due to an electrical current results from Biot-Savart law which states that an electrical current generates a magnetic field. The solidification of the pseudotachylite vein does not happen at once but proceeds from the margin inwards as an electrical current may still pass through the conducting pseudotachylite. Therefore, the host-rock of the pseudotachylite vein or its solidified margin can be magnetized by a coseismic current.

  12. Tensile Characterization of FRP Rods for Reinforced Concrete Structures

    Science.gov (United States)

    Micelli, F.; Nanni, A.

    2003-07-01

    The application of FRP rods as an internal or external reinforcement in new or damaged concrete structures is based on the development of design equations that take into account the mechanical properties of FRP material systems.The measurement of mechanical characteristics of FRP requires a special anchoring and protocol, since it is well known that these characteristics depend on the direction and content of fibers. In this study, an effective tensile test method is described for the mechanical characterization of FRP rods. Twelve types of glass and carbon FRP specimens with different sizes and surface characteristics were tested to validate the procedure proposed. In all, 79 tensile tests were performed, and the results obtained are discussed in this paper. Recommendations are given for specimen preparation and test setup in order to facilitate the further investigation and standardization of the FRP rods used in civil engineering.

  13. Refabrication of fuel rods - qualification of the end plug welds

    International Nuclear Information System (INIS)

    Sannen, Leo; Gys, August; Parthoens, Yves

    2005-01-01

    Refabrication of irradiated fuel rods is applied at SCK/CEN, both to make short fuel rodlets for tests in research reactors and to reconstitute full-size rods for their reinsertion in the original fuel assembly as an elegant back end solution for industrial fuel rods after their use in fuel research programs. In both cases the end cap welds have to be qualified thoroughly, to prove their proper performance either under irradiation and/or during long-term storage. The paper describes the qualification process that is applied at the hot laboratory LHMA at SCK/CEN to qualify the welding methodology and the actual welds made according this methodology. The results obtained on a typical refabrication case are included. (Author)

  14. Unfolding/refolding studies of the myosin rod.

    Science.gov (United States)

    Nozais, M; Bechet, J J

    1993-12-15

    The effect of guanidine hydrochloride on the gel-filtration chromatography, viscosity, far ultraviolet circular dichroism and fluorescence emission intensity of the myosin rod was studied under equilibrium conditions. The normalized transition curves for each of these methods were comparable with a midpoint at a guanidine hydrochloride concentration of 1.75-2 M. The curves were not, however, superposable, suggesting that the loss of helix content and the dissociation of the two chains of the myosin rod were not tightly linked. Furthermore, they were unexpectedly independent of the protein concentration over 0.05-20 microM. These phenomena are interpreted taking into account the large size of the molecule. A step-wise process is proposed as a model for the unfolding of the myosin rod.

  15. Nuclear reactor fuel rod behavior modelling and current trends

    International Nuclear Information System (INIS)

    Colak, Ue.

    2001-01-01

    Safety assessment of nuclear reactors is carried out by simulating the events to taking place in nuclear reactors by realistic computer codes. Such codes are developed in a way that each event is represented by differential equations derived based on physical laws. Nuclear fuel is an important barrier against radioactive fission gas release. The release of radioactivity to environment is the main concern and this can be avoided by preserving the integrity of fuel rod. Therefore, safety analyses should cover an assessment of fuel rod behavior with certain extent. In this study, common approaches for fuel behavior modeling are discussed. Methods utilized by widely accepted computer codes are reviewed. Shortcomings of these methods are explained. Current research topics to improve code reliability and problems encountered in fuel rod behavior modeling are presented

  16. Topologically Directed Assemblies of Semiconducting Sphere-Rod Conjugates.

    Science.gov (United States)

    Lin, Zhiwei; Yang, Xing; Xu, Hui; Sakurai, Tsuneaki; Matsuda, Wakana; Seki, Shu; Zhou, Yangbin; Sun, Jian; Wu, Kuan-Yi; Yan, Xiao-Yun; Zhang, Ruimeng; Huang, Mingjun; Mao, Jialin; Wesdemiotis, Chrys; Aida, Takuzo; Zhang, Wei; Cheng, Stephen Z D

    2017-12-27

    Spontaneous organizations of designed elements with explicit shape and symmetry are essential for developing useful structures and materials. We report the topologically directed assemblies of four categories (a total of 24) of sphere-rod conjugates, composed of a sphere-like fullerene (C 60 ) derivative and a rod-like oligofluorene(s) (OF), both of which are promising organic semiconductor materials. Although the packing of either spheres or rods has been well-studied, conjugates having both shapes substantially enrich resultant assembled structures. Mandated by their shapes and topologies, directed assemblies of these conjugates result not only in diverse unconventional semiconducting supramolecular lattices with controlled domain sizes but also in tunable charge transport properties of the resulting structures. These results demonstrate the importance of persistent molecular topology on hierarchically assembled structures and their final properties.

  17. CFD modeling of secondary flows in fuel rod bundles

    International Nuclear Information System (INIS)

    Baglietto, Emilio; Ninokata, Hisashi

    2004-01-01

    An optimized non-linear eddy viscosity model is introduced, for calculations of detailed coolant velocity distribution in a tight lattice fuel bundle. The low Reynolds formulation has been optimized based on DNS data for channel flow. The non-linear stress-strain relationship has been modified in the coefficients to model the flow anisotropy, which causes the formation of turbulence driven secondary flows inside the bundle subchannels. Predictions of the model are first compared to experimental measurements of secondary flows in a triangularly arrayed rod bundle with p/d=1.3. Subsequently wall shear stress and velocity predictions are compared with different experimental data for a rod bundle with p/d=1.17. The model shows to be able to correctly reproduce the scale of the secondary motion, and to accurately reproduce both wall shear stress and velocity distributions inside the rod bundle subchannels. (author)

  18. Disassembling and cleaning apparatus for control rod drives

    International Nuclear Information System (INIS)

    Yoshida, Tomiji; Sasaki, Masayoshi; Numata, Nobumasa; Oowada, Masataka; Arazoe, Masatoshi.

    1981-01-01

    Purpose: To shorten the working period, as well as decrease the number of operators and radiation exposure doses for disassembling and cleaning of the control rod drives. Constitution: The apparatus comprises a cleaning tank, clamp units, inner and outer surface cleaning nozzles, a high pressure pump, a drying tank unit, electronic components and the likes. This enables to render the various works automatic, such as wash out of outer and inner filters and strainers at high radiation dose levels, extraction and cleaning of a piston tube and an index tube, cleaning for the control rod drive main body, and cleaning and drying of small components, whereby the disassembling, cleaning and assembling works for the control rod drives, among all, the disassembling and cleaning works resulting relatively high radiation exposure doses to the operator can be made in a remote control and semi-automatic manner. (Furukawa, Y.)

  19. Characterisation of Plasma Filled Rod Pinch electron beam diode operation

    Science.gov (United States)

    MacDonald, James; Bland, Simon; Chittenden, Jeremy

    2016-10-01

    The plasma filled rod pinch diode (aka PFRP) offers a small radiographic spot size and a high brightness source. It operates in a very similar to plasma opening switches and dense plasma focus devices - with a plasma prefill, supplied via a number of simple coaxial plasma guns, being snowploughed along a thin rod cathode, before detaching at the end. The aim of this study is to model the PFRP and understand the factors that affect its performance, potentially improving future output. Given the dependence on the PFRP on the prefill, we are making detailed measurements of the density (1015-1018 cm-3), velocity, ionisation and temperature of the plasma emitted from a plasma gun/set of plasma guns. This will then be used to provide initial conditions to the Gorgon 3D MHD code, and the dynamics of the entire rod pinch process studied.

  20. A Method for Determining Reactivity-Time Function of Safety Rods

    International Nuclear Information System (INIS)

    Milovanovic, S.; Pesic, M.

    1994-01-01

    For accidental analysis of HERBE fast-thermal core, an accurate reactivity-time function for reactor safety rods is necessary. The HERBE core was designed with four safety rods: two of them are the actual safety rods, and the other two are additional safety rods which include holds during motion. The reactivity-time function is determined in two steps: (1) safety rods reactivity-position function is measured using inverse method; (2) rod drop position-time function is measured using a new method. In previously proposed method, it was determined by measurement of rod drop times and assuming constant acceleration during any particular interval of a rod motion. The complex dependence of the reactivity-time function for the HERBE safety rods during reactor shutdown is determined by combining both previously obtained reactivity worth data and measurements of safety rods trajectory. Integral reactivity-time function of the safety rods, including rods interference reactivity effects, is shown. In this new method an improvement for accurate safety rod position measurement, compared to previously proposed method, is obtained. At the same time, the assumption of the constant acceleration of the safety rods in the motion intervals is validated

  1. New models of droplet deposition and entrainment for prediction of CHF in cylindrical rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibin, E-mail: hb-zhang@xjtu.edu.cn [School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom); Hewitt, G.F. [Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom)

    2016-08-15

    Highlights: • New models of droplet deposition and entrainment in rod bundles is developed. • A new phenomenological model to predict the CHF in rod bundles is described. • The present model is well able to predict CHF in rod bundles. - Abstract: In this paper, we present a new set of model of droplet deposition and entrainment in cylindrical rod bundles based on the previously proposed model for annuli (effectively a “one-rod” bundle) (2016a). These models make it possible to evaluate the differences of the rates of droplet deposition and entrainment for the respective rods and for the outer tube by taking into account the geometrical characteristics of the rod bundles. Using these models, a phenomenological model to predict the CHF (critical heat flux) for upward annular flow in vertical rod bundles is described. The performance of the model is tested against the experimental data of Becker et al. (1964) for CHF in 3-rod and 7-rod bundles. These data include tests in which only the rods were heated and data for simultaneous uniform and non-uniform heating of the rods and the outer tube. It was shown that the predicted CHFs by the present model agree well with the experimental data and with the experimental observation that dryout occurred first on the outer rods in 7-rod bundles. It is expected that the methodology used will be generally applicable in the prediction of CHF in rod bundles.

  2. An evaluation of control rod motion simulator of research reactor

    International Nuclear Information System (INIS)

    Sanda

    2010-01-01

    Motion simulator for rod control research reactor has been carried out using a servo motor. Reactor rod motion control at any point should be in the right position, one of the motors that can move in a precise and correct is the servo motor. To ensure that the servo motor to move in accordance with the desired program, then the servo motor function test should be carried out to ensure having good performance. Tests carried out on meshes stress disorder, the load is stable within a certain period and travel time safety control rod up and down, travel time regulating control rods up and down and travel time compensation control rods up and down. In testing the breakdown voltage V out nets at 24 V, 6.5 A with 12 Q load deviation obtained V0= V1 = 0.1% and 0.65% and for the stability of the load in a certain time deviation V = 0.7125% , next to the breakdown voltage V out nets at 12 V, 4.2 A with a 6 Q load deviation obtained V0= V1 = 0.275% and 1.158% for the stability of the load in a certain time deviation V = 1.463% and the net-voltage noise nets on V out 24 V, 4.5 A with 12 Q load deviation obtained V0 = V1 = 0.196% and 0.496% and for the stability of the load in a certain time deviation V = 0.3625%. While the travel time of a safety control rod up and down, up and down the regulator and compensation rise and fall showed a steady linear graph. The results show that the performance of the servo motor is very stable with the working area below the tolerance limit, it is 5% - 10%.(author)

  3. Core design of super LWR with double tube water rods

    International Nuclear Information System (INIS)

    Wu, Jianhui; Oka, Yoshiaki

    2014-01-01

    Highlights: • Supercritical light water cooled and moderated reactor with double tube water rods is developed. • Double-row fuel rod assembly and out-in fuel loading pattern are applied. • Separation plates in peripheral assemblies increase average outlet temperature. • Neutronic and thermal design criteria are satisfied during the cycle. - Abstract: Double tube water rods are employed in core design of super LWR to simplify the upper core structure and refueling procedure. The light water moderator flows up in the inner tube from the bottom of the core, then, changes the flow direction at the top of the core into the outer tube and flows out at the bottom of the core. It eliminates the moderator guide/distribution tubes into the single tube water rods from the top dome of the reactor pressure vessel of the previous super LWR design. Two rows of fuel rods are filled between the water rods in the fuel assembly. Out-in refueling pattern is adopted to flatten radial power distribution. The peripheral fuel assemblies of the core are divided into four flow zones by separation plates for increasing the average core outlet temperature. Three enrichment zones are used for axial power flattening. The equilibrium core is analyzed based on neutronic/thermal-hydraulic coupled model. The results show that, by applying the separation plates in peripheral fuel assemblies and low gadolinia enrichment, the maximum cladding surface temperature (MCST) is limited to 653 °C with the average outlet temperature of 500 °C. The inherent safety is satisfied by the negative void reactivity effects and sufficient shutdown margin

  4. Gap conductance in Zircaloy-clad LWR fuel rods

    International Nuclear Information System (INIS)

    Ainscough, J.B.

    1982-04-01

    This report describes the procedures currently used to calculate fuel-cladding gap conductance in light water reactor fuel rods containing pelleted UO 2 in Zircaloy cladding, under both steady-state and transient conditions. The relevant theory is discussed together with some of the approximations usually made in performance modelling codes. The state of the physical property data which are needed for heat transfer calculations is examined and some of the relevant in- and out-of-reactor experimental work on fuel rod conductance is reviewed

  5. Experiments to understand the corrosion process of fuel rod claddings

    International Nuclear Information System (INIS)

    Groeschel, F.; Hermann, A.

    1997-01-01

    Fuel rods in light water reactors have to respond to the trends in increased burn-up and extended dwelling time in reactor. Waterside corrosion of the cladding affecting wall thickness, mechanical stability due to hydriding and the heat transfer due to the low thermal conductivity of the oxide scale may become the limiting factors. The corrosion process is complex and involves a large variety of mechanisms. Understanding of the process is important for safe operation and a prerequisite for development of improved materials. A variety of analytical techniques and mechanical tests, including examination of irradiated pathfinder rods, are used to tackle the different aspects. (author) 6 figs., 1 tab., 17 refs

  6. Grid supports design for dual-cooled fuel rods

    Directory of Open Access Journals (Sweden)

    J Kim

    2016-09-01

    In this paper, the minimum spring force to prevent dual-cooled fuel rods from dropping during normal reactor operation is calculated. The spring characteristics of a cantilever type and a hemi-sphere type are predicted. A finite element analysis is carried out by using the commercial code ABAQUS. The analysis results are verified by experiments. Finally, it is checked whether the property of the suggested springs satisfies the minimum required spring force. Based on the obtained results, a kind of spacer grid candidate for dual cooled fuel rods, i.e. a spacer grid with hybrid supports is suggested.

  7. Determination of Ultimate Torque for Multiply Connected Cross Section Rod

    Directory of Open Access Journals (Sweden)

    V. L. Danilov

    2015-01-01

    Full Text Available The aim of this work is to determine load-carrying capability of the multiply cross-section rod. This calculation is based on the model of the ideal plasticity of the material, so that the desired ultimate torque is a torque at which the entire cross section goes into a plastic state.The article discusses the cylindrical multiply cross-section rod. To satisfy the equilibrium equation and the condition of plasticity simultaneously, two stress function Ф and φ are introduced. By mathematical transformations it has been proved that Ф is constant along the path, and a formula to find its values on the contours has been obtained. The paper also presents the rationale of the line of stress discontinuity and obtained relationships, which allow us to derive the equations break lines for simple interaction of neighboring circuits, such as two lines, straight lines and circles, circles and a different sign of the curvature.After substitution into the boundary condition at the end of the stress function Ф and mathematical transformations a formula is obtained to determine the ultimate torque for the multiply cross-section rod.Using the doubly connected cross-section and three-connected cross-section rods as an example the application of the formula of ultimate torque is studied.For doubly connected cross-section rod, the paper offers a formula of the torque versus the radius of the rod, the aperture radius and the distance between their centers. It also clearly demonstrates the torque dependence both on the ratio of the radii and on the displacement of hole. It is shown that the value of the torque is more influenced by the displacement of hole, rather than by the ratio of the radii.For the three-connected cross-section rod the paper shows the integration feature that consists in selection of a coordinate system. As an example, the ultimate torque is found by two methods: analytical one and 3D modeling. The method of 3D modeling is based on the Nadai

  8. Periodicity effects of axial waves in elastic compound rods

    DEFF Research Database (Denmark)

    Nielsen, R. B.; Sorokin, S. V.

    2015-01-01

    Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase-closure Prin......Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase...

  9. Detection of Microcracks in Trunnion Rods Using Ultrasonic Guided Waves

    Science.gov (United States)

    2015-07-01

    detection in rod waveguides, such as rock and soil anchors, are well described in a number of papers (Beard and Lowe 2003; He 2006 et al.; Yang 2011...anchor corrosion in soils (Beard et al.2003; Yang 2011; He et al. 2006). In general, these specific applications need high sensitivity at the rod...dimensional (3D) finite element modeling ( FEM ) as a means to avoid ERDC/ITL TR-15-1 17 pull-off requirements. It is important to note that this LF

  10. Review of design technology of control rod position indicators

    International Nuclear Information System (INIS)

    Yu, Je Yong; Huh, Hyung; Kim, Ji Ho; Kim, Jong In; Chang, Moon Hee

    1999-10-01

    An integral reactor SMART is under development at KAERI. The design characteristics of SMART are radically different from those employer in currently operating loop type water reactors in Korea. The objective of this report is to review the design technology of position indicator, and to study the various sensors which can be used in rod position indicator. Design criteria that rod position indicator should satisfy are also examined. Following position indicators are reviewed in this report. 1. Digital positioning indicator (DRPI), 2. Reed switch type position indicator (RSPT), 3. Choke sensor type position indicator, 4. Ultrasonic sensor type position indicator, 5. Comparison of each position indicator. (author)

  11. Operation of a 473 MHz four-rod cavity RFQ

    International Nuclear Information System (INIS)

    Kazimi, R.; Huson, F.R.; Mackay, W.W.; Meitzler, C.R.

    1992-01-01

    We have constructed a new type of four-rod Radio Frequency Quadrupole to operate at 473 MHz. Four-rod structures have not previously been built for such a high frequency. The RFQ is designed to accelerate 10 mA of H - ions from 30 keV to 0.5 MeV. The rf measurements and beam test of the RFQ have been performed successfully. Here we present operational results of the RFQ system including measurements of the beam current, the required rf power, energy, energy spread, and emittance. (Author) 8 refs., 6 figs., 2 tabs

  12. Critical experiments supporting underwater storage of tightly packed configurations of spent fuel rods

    International Nuclear Information System (INIS)

    Hoovler, G.S.; Baldwin, M.N.

    1981-04-01

    Criticla arrays of 2.5%-enriched UO 2 fuel rods that simulate underwater rod storage of spent power reactor fuel are being constructed. Rod storage is a term used to describe a spent fuel storage concept in which the fuel bundles are disassembled and the rods are packed into specially designed cannisters. Rod storage would substantially increase the amount of fuel that could be stored in available space. These experiments are providing criticality data against which to benchmark nuclear codes used to design tightly packed rod storage racks

  13. Competitiveness of organically grown cereals

    Directory of Open Access Journals (Sweden)

    Jaroslav Jánský

    2007-01-01

    Full Text Available The contribution is aimed at the assessment of recommended crop management practices of chosen cereals for organic farming. To increase competitiveness, these practices are modified depending on soil and climatic conditions, and on a way of production use. Furthermore, impacts of the recommended crop management practices on economics of growing chosen cereals are evaluated and compared with economic results obtained under conventional farming. It is assumed that achieved results will contribute to the increase in proportion of arable crops in the Czech Republic where organic production offer does not meet current demands.When evaluating results of growing individual cereal species in a selective set of organic farms, triticale, spelt and spring barley (in this ranking can be considered as profitable crops. Moreover, triticale and spelt have even higher gross margin under organic farming than under conventional farming (by 62 % in triticale. Oat brings losses, however, it is important for livestock production. Winter wheat seems to be also unprofitable since less grain is produced at lower imputs per hectare and only part of it is produced in quality “bio”, i.e. marketed for higher prices. Rye also brings losses under organic farming, particularly due to lower yields, similarly to the other mentioned cereals. Special cereal species that are still neglected in organic farming systems are of potential use. Durum wheat has vitreous kernels with a high content of quality gluten which is used for pasta production. It can be grown in the maize production area on fertile soils only.

  14. NANOSIZED MAGNESIUM OXIDE AS CATALYST FOR THE RAPID AND GREEN SYNTHESIS OF SUBSTITUTED 2-AMINO-2-CHROMENES

    Science.gov (United States)

    A nanosized magnesium oxide catalyzed three-component condensation reaction of aldehyde, malononitrile and ¿-naphthol proceeded rapidly in water/PEG to afford corresponding 2-amino-2-chromenes in high yields at room temperature. The greener protocol was found to be fairly general...

  15. A new approach to incorporating the effect of nano-sized dispersoids on recrystallization inhibition into Monte Carlo simulation

    NARCIS (Netherlands)

    Eivani, A. R.; Zhou, J.; Duszczyk, J.

    In this research, a new approach to incorporating the effect of nano-sized dispersoids on recrystallization was developed as a combination of physical modeling and Monte Carlo simulation. The energy stored during preceding deformation and the nucleation rate at the onset and during recrystallization

  16. Synthesis and characterization of nano-sized BaxSr1–xSO4 (0 ≤ x ...

    Indian Academy of Sciences (India)

    Administrator

    Synthesis and characterization of nano-sized BaxSr1–xSO4 (0 ≤ x ≤ 1) solid solution by a simple surfactant-free aqueous solution route. YU-FENG LI, JIA-HU OUYANG*, YU ZHOU, XUE-SONG LIANG and JI-YONG ZHONG. Institute for Advanced Ceramics, Department of Materials Science, Harbin Institute of Technology,.

  17. Presence of nano-sized silica during in vitro digestion of foods containing silica as a food additive.

    NARCIS (Netherlands)

    Peters, R.; Kramer, E.; Oomen, A.G.; Rivera, Z.E.; Oegema, G.; Tromp, P.C.; Fokkink, R.; Rietveld, A.; Marvin, H.J.; Weigel, S.; Peijnenburg, A.A.; Bouwmeester, H.

    2012-01-01

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products

  18. Presence of Nano-Sized Silica during In Vitro Digestion of Foods Containing Silica as a Food Additive

    NARCIS (Netherlands)

    Peters, R.J.B.; Kramer, E.H.M.; Oomen, A.G.; Rivera, Z.H.; Oegema, G.; Tromp, P.C.; Fokkink, R.G.; Rietveld, A.; Marvin, H.J.P.; Weigel, S.; Peijnenburg, A.A.C.M.; Bouwmeester, H.

    2012-01-01

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products

  19. Presence of nano-sized silica during in vitro digestion of foods containing silica as a food additive

    NARCIS (Netherlands)

    Peters, R.; Kramer, E.; Oomen, A.G.; Herrera Rivera, Z.E.; Oegema, G.; Tromp, P.C.; Fokkink, R.; Rietveld, A.; Marvin, H.J.P.; Weigel, S.; Peijnenburg, A.A.C.M.; Bouwmeester, H.

    2012-01-01

    The presence, dissolution, agglomeration state, and release of materials in the nano-size range from food containing engineered nanoparticles during human digestion is a key question for the safety assessment of these materials. We used an in vitro model to mimic the human digestion. Food products

  20. Hybrid composites of nano-sized zero valent iron and covalent organic polymers for groundwater contaminant degradation

    DEFF Research Database (Denmark)

    Mines, Paul D.; Byun, J.; Hwang, Yuhoon

    Zero valent iron is commonly used in a variety of treatment technologies (e.g. permeable reactive barriers), though recently a heavier focus has been placed on nano-sized zero valent iron (nZVI). Having superior reductive properties and large surface areas, nZVI is ideal for the degradation of ch...

  1. Nanosized TiO[subscript 2] for Photocatalytic Water Splitting Studied by Oxygen Sensor and Data Logger

    Science.gov (United States)

    Zhang, Ruinan; Liu, Song; Yuan, Hongyan; Xiao, Dan; Choi, Martin M. F.

    2012-01-01

    Photocatalytic water splitting by semiconductor photocatalysts has attracted considerable attention in the past few decades. In this experiment, nanosized titanium dioxide (nano-TiO[subscript 2]) particles are used to photocatalytically split water, which is then monitored by an oxygen sensor. Sacrificial reagents such as organics (EDTA) and metal…

  2. WC-Co COATINGS AND SINTERS MODIFIED WITH NANO-SIZED TiC MICROSTRUCTURE – QUANTITATIVE EVALUATION

    Directory of Open Access Journals (Sweden)

    Hanna Myalska

    2017-03-01

    Full Text Available The different concepts of WC-Co thermally sprayed coatings improvement may be considered and the application of nanoparticles, as the mechanical strengthening addition, is one of them. Nanostructured WC-Co coatings are characterized by higher hardness than the coatings formed from micrometric WC grains; whereas coatings with bimodal distribution of particles reveal greater wear resistance than the coatings obtained exclusively from nano-sized powders. Mixed effect of the matrix reinforcement by nanoparticles and strong fix of the micron-sized WC grains was proposed as a possible reason for enhanced wear resistance of bimodal coatings. In order to obtain a bimodal distribution of particles in the material standard WC-Co (83-17 powder was mixed with nanometric TiC powder (40-100 nm. The amount of TiC in powder mixtures was in the range from 1 to 7 wt.%. The mixtures were deposited on steel substrate using HVAF method and also hot pressed in vacuum. The microstructure of obtained coatings and sinters was quantitatively evaluated. Sinters revealed more homogenous distribution of the nano-sized TiC particles than the coatings. The addition of nano-sized TiC in the case of coatings has led to the decrease of its porosity. The agglomeration of nano-sized TiC particles in the coatings results in the decrease of material’s hardness.

  3. Tribological Behavior of Nano-Sized SiCp/7075 Composite Parts Formed by Semisolid Processing

    Directory of Open Access Journals (Sweden)

    Jufu Jiang

    2018-02-01

    Full Text Available The tribological behavior of the rheoformed and thixoformed nano-sized SiCp/7075 composite parts is investigated. The semisolid stirring temperature has a little influence on the friction coefficient and wear resistance of the rheoformed composite parts. As for the thixoformed composite parts, the average value of the steady-state coefficient of friction increases firstly and then decreases with increasing reheating temperature. Higher wear resistance is achieved at a reheating temperature of 580 °C. The average value of the steady-state friction coefficient of the rheoformed composite parts varies from 0.37 to 0.45 upon applied loads of from 20 to 50 N. Weight loss increases slightly upon an increase of applied load from 20 to 40 N. An applied load of 50 N leads to a significant increase of the weight loss. The wear rate decreases firstly and then increases with increasing applied load. As for the thixoformed composite part, the average value of the steady-state friction coefficient and the weight loss decreased with an increasing applied load. However, the wear rate decreases firstly with increasing applied load and then increases. As for the rheoformed composite part, the average value of the steady-state friction coefficient decreases firstly and then increases a little with increasing sliding velocity. Weight loss and wear rate show a first increase and a followed decrease with increasing sliding velocity. As for the thixoformed composite part, the average value of the steady-state friction coefficient shows a decrease with increasing sliding velocity. Weight loss and wear rate exhibit, at first, an increase, and then a decrease with increasing sliding velocity. The average friction coefficient varies from 0.4 to 0.44 with increasing volume fraction of SiC. Weight loss and wear rate decrease with increasing volume fraction of SiC. An increase in dislocation density around the nano-sized SiC particles and the mismatch of the coefficient of

  4. Preparation, characterization and application of nanosized copper ferrite photocatalysts for dye degradation under UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zaharieva, Katerina, E-mail: zaharieva@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Rives, Vicente, E-mail: vrives@usal.es [GIR-QUESCAT, Dpto. Química Inorgánica, Universidad de Salamanca, 37008 Salamanca (Spain); Tsvetkov, Martin, E-mail: mptsvetkov@gmail.com [Faculty of Chemistry and Pharmacy, St. Kliment Ohridski University of Sofia, 1 J. Bourchier Blvd., 1164 Sofia (Bulgaria); Cherkezova-Zheleva, Zara, E-mail: zzhel@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Kunev, Boris, E-mail: bkunev@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Trujillano, Raquel, E-mail: rakel@usal.es [GIR-QUESCAT, Dpto. Química Inorgánica, Universidad de Salamanca, 37008 Salamanca (Spain); Mitov, Ivan, E-mail: mitov@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 11, 1113 Sofia (Bulgaria); Milanova, Maria, E-mail: nhmm@wmail.chem.uni-sofia.bg [Faculty of Chemistry and Pharmacy, St. Kliment Ohridski University of Sofia, 1 J. Bourchier Blvd., 1164 Sofia (Bulgaria)

    2015-06-15

    Nanosized copper ferrite-type materials (Cu{sub x}Fe{sub 3–x}O{sub 4}, 0 ≤ x ≤ 1) have been prepared by combination of co-precipitation and mechanochemical activation and/or thermal treatment. The crystalline structure and morphology of the obtained ferrite nanopowders have been characterized by different instrumental methods, such as Powder X-ray diffraction (PXRD), Mössbauer and FT-IR spectroscopies, specific surface area and porosity measurements, thermal analyses (Differential Thermal Analysis and Thermogravimetric Analysis) and Temperature-Programmed Reduction. The average crystallite size of copper ferrites ranged between 7.8 and 14.7 nm and show a superparamagnetic and collective magnetic excitations nature. The photocatalytic decolorization of Malachite green oxalate under different UV illumination intervals was examined using these copper ferrites as photocatalysts. The results indicate that the prepared nanostructured copper ferrites showed enhanced photocatalytic activity and amount adsorbed Malachite Green dye. The co-precipitated nanosized copper ferrite powder with a low content of copper metal ions in a magnetite host structure (Cu{sub 0.25}Fe{sub 2.75}O{sub 4}) showed an apparent pseudo-first-order rate constant 15.4 × 10{sup −3} min{sup −1} and an amount adsorbed Malachite Green as model organic dye pollutant per 1 g catalyst of 33.4 ppm/g after the dark period. The results confirm that the copper ferrites can be suitable for photocatalytic treatment of wastewaters containing organic dyes. The new aspect of presented investigations is to study the influence of different degree of incorporation of copper ions into the magnetite host structure and preparation methods on the photocatalytic properties of nanosized copper ferrite materials and obtaining of potential photocatalyst (Cu{sub 0.25}Fe{sub 2.75}O{sub 4}) with higher photocatalytic activity (15.4 × 10{sup −3} min{sup −1}) than that of the standard referent Degussa P25 (12 × 10

  5. Preparation, characterization and application of nanosized copper ferrite photocatalysts for dye degradation under UV irradiation

    International Nuclear Information System (INIS)

    Zaharieva, Katerina; Rives, Vicente; Tsvetkov, Martin; Cherkezova-Zheleva, Zara; Kunev, Boris; Trujillano, Raquel; Mitov, Ivan; Milanova, Maria

    2015-01-01

    Nanosized copper ferrite-type materials (Cu x Fe 3–x O 4 , 0 ≤ x ≤ 1) have been prepared by combination of co-precipitation and mechanochemical activation and/or thermal treatment. The crystalline structure and morphology of the obtained ferrite nanopowders have been characterized by different instrumental methods, such as Powder X-ray diffraction (PXRD), Mössbauer and FT-IR spectroscopies, specific surface area and porosity measurements, thermal analyses (Differential Thermal Analysis and Thermogravimetric Analysis) and Temperature-Programmed Reduction. The average crystallite size of copper ferrites ranged between 7.8 and 14.7 nm and show a superparamagnetic and collective magnetic excitations nature. The photocatalytic decolorization of Malachite green oxalate under different UV illumination intervals was examined using these copper ferrites as photocatalysts. The results indicate that the prepared nanostructured copper ferrites showed enhanced photocatalytic activity and amount adsorbed Malachite Green dye. The co-precipitated nanosized copper ferrite powder with a low content of copper metal ions in a magnetite host structure (Cu 0.25 Fe 2.75 O 4 ) showed an apparent pseudo-first-order rate constant 15.4 × 10 −3 min −1 and an amount adsorbed Malachite Green as model organic dye pollutant per 1 g catalyst of 33.4 ppm/g after the dark period. The results confirm that the copper ferrites can be suitable for photocatalytic treatment of wastewaters containing organic dyes. The new aspect of presented investigations is to study the influence of different degree of incorporation of copper ions into the magnetite host structure and preparation methods on the photocatalytic properties of nanosized copper ferrite materials and obtaining of potential photocatalyst (Cu 0.25 Fe 2.75 O 4 ) with higher photocatalytic activity (15.4 × 10 −3 min −1 ) than that of the standard referent Degussa P25 (12 × 10 −3 min −1 ) for degradation of organic dye

  6. Design, modeling, expression, and chemoselective PEGylation of a new nanosize cysteine analog of erythropoietin

    Directory of Open Access Journals (Sweden)

    Ahangari Cohan R

    2011-06-01

    Full Text Available Reza Ahangari Cohan1, Armin Madadkar-Sobhani2,3, Hossein Khanahmad1, Farzin Roohvand4, Mohammad Reza Aghasadeghi4, Mohammad Hossein Hedayati5, Zahra Barghi5, Mehdi Shafiee Ardestani4, Davoud Nouri Inanlou1, Dariush Norouzian11Research and Development Department, Production and Research Complex, Pasteur Institute of Iran, Tehran, Iran; 2Department of Bioinformatics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; 3Department of Life Sciences, Barcelona Supercomputing Center, Barcelona, Spain; 4Hepatitis and AIDS Department, Pasteur Institute of Iran, Tehran, Iran; 5Quality Control Department, Production and Research Complex, Pasteur Institute of Iran, Tehran, IranBackground: Recombinant human erythropoietin (rhEPO is considered to be one of the most pivotal pharmaceutical drugs in the market because of its clinical application in the treatment of anemia-associated disorders worldwide. However, like other therapeutic proteins, it does not have suitable pharmacokinetic properties for it to be administrated at least two to three times per week. Chemoselective cysteine PEGylation, employing molecular dynamics and graphics in in silico studies, can be considered to overcome such a problem.Methods: A special kind of EPO analog was elicited based on a literature review, homology modeling, molecular dynamic simulation, and factors affecting the PEGylation reaction. Then, cDNA of the selected analog was generated by site-directed mutagenesis and subsequently cloned into the expression vector. The construct was transfected to Chinese hamster ovary/dhfr- cells, and highly expressed clones were selected via methotrexate amplification. Ion-immobilized affinity and size exclusion (SE chromatography techniques were used to purify the expressed analog. Thereafter, chemoselective PEGylation was performed and a nanosize PEGylated EPO was obtained through dialysis. The in vitro biologic assay and in vivo pharmacokinetic parameters were

  7. The improvement of control rod in experimental fast reactor JOYO. The development of a sodium bonded type control rod

    Energy Technology Data Exchange (ETDEWEB)

    Soga, T.; Miyakawa, S.; Mitsugi, T. [Japan Nuclear Cycle Development Inst., Oarai Engineering Center, Irradiation Center, Irradiation and Administration Section, Oarai, Ibaraki (Japan)

    1999-06-01

    Currently, the lifetime of control rods in JOYO is limited by Absorber-Cladding Mechanical Interaction (ACMI) due to swelling of B{sub 4}C(boron carbide) pellets accelerated by relocation of pellet fragments. A sodium bonded type control rod was developed which improves the thermal conductivity by means of charging sodium into the gap between B{sub 4}C and cladding and by utilizing a shroud which wraps the pellet fragments in a thin tube. This new design will be able to enlarge the gap between B{sub 4}C and cladding, without heating B{sub 4}C or fragment relocation, thus extending the life of the control rod. The sodium bonded type will be fabricated as the ninth reload control rods in JOYO. (1) The specification of a sodium bonded type control rod was determined with the wide gap between B{sub 4}C and cladding. In the design simulation, main component temperature were below the maximum limit. And the local heating by helium bubble generated from B{sub 4}C in the sodium gap, was not a serious problem in the analysis which was considered. (2) A structural design for the sodium entrance into the pin was determined. A formula was developed which the limit for sodium charging given physical dimension of the structure and sodium property. Result from sodium out-pile experiments validated the theoretical formula. (3) The analysis of ACMI indicated a lifetime extension of the sodium bonded type by 4.6% in comparison with lifetime of the helium bonded type of 1.6%. This is due to the boron10 burn-up rate being three times higher in the sodium bonded type than in the helium bonded type. To achieve a target burn-up 10% in the future, it will be necessary to modify design based on irradiation data which will be obtained by practical use of the sodium bonded control rods in JOYO. (4) The effects due to Absorber-Cladding Chemical Interaction (ACCI) were reduced by controlling the cladding temperature and chromium coating to the cladding's inner surface. It was confirmed

  8. Status of work on the final repository concept concerning direct disposal of spent fuel rods in fuel rod casks (BSK)

    International Nuclear Information System (INIS)

    Filbert, W.; Wehrmann, J.; Bollingerfehr, W.; Graf, R.; Fopp, S.

    2008-01-01

    The reference concept in Germany on direct final storage of spent fuel rods is the burial of POLLUX containers in the final repository salt dome. The POLLUX container is self-shielded. The final storage concept also includes un-shielded borehole storage of high-level waste and packages of compacted waste. GNS has developed a spent fuel container (BSK-3) for unshielded borehole storage with a mass of 5.2 tons that can carry the fuel rods of three PWR reactors of 9 BWR reactors. The advantages of BSK storage include space saving, faster storage processes, less requirements concerning technical barriers, cost savings for self-shielded casks.

  9. Fuel rod analysis to respond to high burnup and demanding loading requirements. Probabilistic methodology recovers design margins narrowed by degrading fuel thermal conductivity and progressing FGR

    International Nuclear Information System (INIS)

    Eberle, R.; Heins, L.; Sontheimer, F.

    1997-01-01

    The proof that fuel rods will safely withstand all loads arising from inpile service conditions is generally achieved through the assessment of a number of design criteria by using a conservative analysis methodology in conjunction with design limits ''on the safe side''. The classical approach is the application of a fuel rod code to the Worst Case which is defined by the combination of most unfavorable conditions and assumptions with respect to the criterion under consideration. As it is evident that the deterministic construction of such Worst Cases imply an (unknown but) intuitively very high degree of conservatism, it is not surprising that this will develop to cause problems the more demanding fuel insertion conditions have to be anticipated (increased burnup, high efficiency loading schemes, etc.). A certain relief can be gained form cautious revisions of single design limits based on grown performance experience. But this increase of knowledge allows as well to change the established deterministic ''go/no-go'' conception into a better differentiating assessment methodology by which the quantification of the implied conservatism and the remaining design margins is possible: the Probabilistic Design Methodology (PDM). Principles and elements of the PDM are described. An essential prerequisite is a best-estimate fuel rod code which incorporates the latest state of knowledge about potential performance limiting phenomena (e.g. burnup degradation of fuel oxide thermal conductivity) as Siemens/KWU's CARO-E does. An example is given how input distributions for rod data and model parameters transfer into a frequency distribution of maximum rod internal pressure, and indications are given how this is to be interpreted in view of a probabilistically re-formulated design criterion. The PDM provides a realistic conservative assessment of design criteria and will thus recover design margins for increasingly aggravated loading conditions. (author). 9 refs, 9 figs, 2 tabs

  10. Cholesteric colloidal liquid crystals from phytosterol rod-like particles

    NARCIS (Netherlands)

    Rossi, L.; Sacanna, S.; Velikov, K.P.

    2011-01-01

    We report the first observation of chiral colloidal liquid crystals of rod-like particles from a low molecular weight organic compound— phytosterols. Based on the particles shape and crystal structure, we attribute this phenomenon to chiral distribution of surface charge on the surface of

  11. Rigid rod spaced fullerene as building block for nanoclusters

    Indian Academy of Sciences (India)

    By using phenylacetylene based rigid-rod linkers (PhA), we have successfully synthesized two fullerene derivatives, C60-PhA and C60-PhA-C60. The absorption spectral features of C60, as well as that of the phenylacetylene moiety are retained in the monomeric forms of these fullerene derivatives, ruling out the possibility ...

  12. Problem of radioactive lightning rods in the Republic of Croatia

    International Nuclear Information System (INIS)

    Novakovic, M.

    1994-01-01

    It became evident that as in most countries in Europe and other world, the radioactive lightning preventers will be prohibited in Croatia. It has to be done gradually and in phases. About 50% of whole number of radioactive lightning rods is mounted on hotels, and other are on industrial objects. Request for immediate replacement of them can almost fully load the available storage with radioactive waste, and the ex users should spent a significant sums of money to built an alternative lightning protection. One of the options is to use dismounted sources and use them for some other convenient purpose even for renewing the other radioactive lightning rod. In our opinion the best is to prohibit installation of the new lightning rods and existing ones dismount after elapsing the time for replacement of the radioactive attachment. After some years all radioactive lightning rods would be dismounted with smaller financial burden to ex users and community resulting also with less net amounts of radioactive waste

  13. Further delineation of spondylometaphyseal dysplasia with cone-rod dystrophy

    NARCIS (Netherlands)

    Sousa, Sérgio B.; Russell-Eggitt, Isabelle; Hall, Christine; Hall, Bryan D.; Hennekam, Raoul C. M.

    2008-01-01

    There are several entities that combine a skeletal dysplasia with a retinal dystrophy. Recently, another possibly autosomal recessive entity was added to this group characterized by a specific spondylometaphyseal dysplasia and a cone-rod dystrophy, without other significant impairments. The entity

  14. Fabrication of control rods for the High Flux Isotope Reactor

    International Nuclear Information System (INIS)

    Sease, J.D.

    1998-01-01

    The High Flux Isotope Reactor (HFIR) is a research-type nuclear reactor that was designed and built in the early 1960s and has been in continuous operation since its initial criticality in 1965. Under current plans, the HFIR is expected to continue in operation until 2035. This report updates ORNL/TM-9365, Fabrication Procedure for HFIR Control Plates, which was mainly prepared in the early 1970's but was not issued until 1984, and reflects process changes, lessons learned in the latest control rod fabrication campaign, and suggested process improvements to be considered in future campaigns. Most of the personnel involved with the initial development of the processes and in part campaigns have retired or will retire soon. Because their unlikely availability in future campaigns, emphasis has been placed on providing some explanation of why the processes were selected and some discussions about the importance of controlling critical process parameters. Contained in this report is a description of the function of control rods in the reactor, the brief history of the development of control rod fabrication processes, and a description of procedures used in the fabrication of control rods. A listing of the controlled documents and procedures used in the last fabrication campaigns is referenced in Appendix A

  15. CEA data and methods for control rod calculations

    International Nuclear Information System (INIS)

    Salvatores, M.

    1988-01-01

    Methods and data used at CEA for LMFBR control rod calculations are presented. The performances of both the design methods and of the refined methods for the SUPER PHENIX start-up experiments are given. New developments for future core design and operation are also reported, together with the role of integral experiments to validate them. (author). 15 refs, 4 figs, 11 tabs

  16. Efficient Electroluminescence from a New Conjugated Rigid-Rod Polyquinoline

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1998-01-01

    A new conjugated rigid-rod polyquinoline, poly (2,2'-p-phenylene)-6,6'-bis(4-(p-tert-butylphenyl)quinoline)), was synthesized and its thin film was used as the emissive layer in light-emitting diodes...

  17. Hydraulic pressure control unit for control rod drive

    International Nuclear Information System (INIS)

    Watabe, Yukio.

    1990-01-01

    The pressure invention concerns a hydraulic pressure control unit for control rod drives in BWR type reactors. The space above a floating piston possessed by an accumulator and the housing of control rod drives are connected by means of a pipeline. The pipeline has a scram valve which is opened upon occurrence of reactor scram. A pump is disposed between the accumulator and the scram valve for communicating a discharge port to apply a high pressure water to the accumulator. According to the present invention, a control unit is disposed between the scram valve and the housing of the control rod drives in the hydraulic pressure control unit for maintaining the cross sectional area of the flow channel of the pipeline to a usual size when the pressure in a pressure vessel is under a rated operation pressure, while limiting the cross sectional area of the flow channel when the pressure is lower than that in the rated operation. Thus, whole insertion of the control rod substantially at a constant speed is enabled irrespective of the level of the pressure in the pressure vessel. (I.S.)

  18. Hemispheric Correlates of the Rod-And-Frame Test.

    Science.gov (United States)

    Berlin, Donna F.; Languis, Marlin L.

    1981-01-01

    Right-handed sixth graders were administered the WISC Block Design and verbal and nonverbal versions of the Rod-and-Frame Test (RFT), measuring field dependence/independence. Results seemed to reflect a right hemisphere processing for the nonverbal RFT and a possible sex bias against girls in its traditional verbal administration. (Author/SJL)

  19. System and method for consolidating spent fuel rods

    International Nuclear Information System (INIS)

    Baudro, T.O.

    1987-01-01

    A system is described for consolidating spent fuel rods from spent fuel assemblies, comprising: a consolidation container in which the fuel rods may be packed; a frame capable of holding a fuel assembly and the container during consolidation, the frame permitting each of the fuel assembly and the container to be removed; tool means with gripper means for gripping and releasing a rod, the tool means including means for moving the gripper means upwardly and downwardly; a first indexing head having first guide means for guiding the gripper means while the gripper means moves downwardly; a first rail, the first indexing head being slidably mounted on the first rail; a second indexing head having second guide means for guiding the gripper means while the gripper means moves downwardly; a second rail, the second indexing head being slidably mounted on the second rail; and a third rail, the first rail and the second rail being slidably mounted on the third rail; wherein the first indexing head is slidable on the first and third rails to a first position that is above a preselected rod in the fuel assembly; and wherein the second indexing head is slidable on the second and third rails to a second position that is above a preselected location in the container

  20. Hydraulic testing of accelerator-production-of-tritium rod bundles

    International Nuclear Information System (INIS)

    Spatz, T.L.; Siebe, D.A.

    1999-01-01

    Hydraulic tests have been performed on small pitch-to-diameter-ratio rod bundles using light water (1.7 Tr < 13,000). Also presented is the comparison of the overall rung pressure drop to a solution based on hydraulic-resistance handbook calculations