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Sample records for absorber rods tpbars

  1. DESCRIPTION OF THE TRITIUM-PRODUCING BURNABLE ABSORBER ROD FOR THE COMMERCIAL LIGHT WATER REACTOR TTQP-1-015 Rev 19

    SciTech Connect

    Burns, Kimberly A.; Love, Edward F.; Thornhill, Cheryl K.

    2012-02-01

    Tritium-producing burnable absorber rods (TPBARs) used in the U.S. Department of Energy’s Tritium Readiness Program are designed to produce tritium when placed in a Westinghouse or Framatome 17x17 fuel assembly and irradiated in a pressurized water reactor (PWR). This document provides an unclassified description of the current design baseline for the TPBARs. This design baseline is currently valid only for Watts Bar reactor production cores. A description of the Lead Use TPBARs will not be covered in the text of the document, but the applicable drawings, specifications and test plan will be included in the appropriate appendices.

  2. TRANSPORT AND REDUCTION POSSIBILITIES DURING TPBAR EXTRACTION

    SciTech Connect

    Korinko, P

    2008-05-19

    In light of the discovery of the activated zinc 65 in the TEF process piping, a discussion of potential sources and mechanisms for the production of this species has been initiated. A suspected source is the presence of Cu as a contaminant in many of the alloy components that comprise the TPBARs and the presence of Zn as a contaminant in the aluminide coating. These two sources are expected to produce metallic transmutation products that could be mobile and be extracted from the metallic components of the TPBARs. Another potential source is the presence of ZnO that is present as part of the crud on the external surfaces of the TPBARs. In addition, it is conceivable to have ZnO within the TPBARs from transmutation products and subsequent oxidation reactions with water. This memo does not attempt to address all of the possible sources, nor does it derive the most likely scenarios as to how Zn or ZnO may be present in the TPBARs it merely posits that it is present as a transmutation product and if present, elementally, it may be mobile under high vacuum conditions at high temperatures as indicated by the pressure temperature curve shown in Fig. 1. Further, this document shows that it is thermodynamically feasible to reduce ZnO to Zn by solid state reactions of the ZnO with other metallic components in the TPBARs. However, for these reactions to occur, the ZnO must be in contact with the more active metal so that the chemical reactions can occur. The proposed reactions are based on equilibrium thermodynamics. For simplicity, they do not take into account the quantities of the various materials, the compositions, the effect of alloying, or other technical issues, they are intended only to provide feasibility for the reduction reactions. A more complete thermodynamic model can be developed, but it will require actual contents and be much more complicated with little value added.

  3. Dysprosium titanate as an absorber material for control rods

    NASA Astrophysics Data System (ADS)

    Risovany, V. D.; Varlashova, E. E.; Suslov, D. N.

    2000-09-01

    Disprosium titanate is an attractive control rod material for the thermal neutron reactors. Its main advantages are: insignificant swelling, no out-gassing under neutron irradiation, rather high neutron efficiency, a high melting point (˜1870°C), non-interaction with the cladding at temperatures above 1000°C, simple fabrication and easily reprocessed non-radioactive waste. It can be used in control rods as pellets and powder. The disprosium titanate control rods have worked off in the MIR reactor for 17 years, in VVER-1000 - for 4 years without any operating problems. After post-irradiation examinations this type of control rod having high lifetime was recommended for the VVER and RBMK. The paper presents the examination results of absorber element dummies containing dysprosium titanate, irradiated in the SM reactor to the neutron fluence of 3.4×10 22 cm -2 ( E>0.1 MeV) and, also, the data on structure, thermal-physical properties of dysprosium titanate, efficiency of dysprosium titanate control rods.

  4. Report on the evaluation of the tritium producing burnable absorber rod lead test assembly. Revision 1

    SciTech Connect

    1997-03-01

    This report describes the design and fabrication requirements for a tritium-producing burnable absorber rod lead test assembly and evaluates the safety issues associated with tritium-producing burnable absorber rod irradiation on the operation of a commercial light water reactor. The report provides an evaluation of the tritium-producing burnable absorber rod design and concludes that irradiation can be performed within U.S. Nuclear Regulatory Commission regulations applicable to a commercial pressurized light water reactor.

  5. Tritium Technology Program TTP-1-3089 TPBAR Homogenized Composition

    SciTech Connect

    Love, Edward F.

    2014-10-12

    Homogenized TPBAR number densities contained herein have been derived for unclassified core physics calculations. The use of this information may not provide accurate, conservative or representative results and must be evaluated for applicability to the specific problem.

  6. Simulation Analysis of Resonant Frequency of Mix Sucker Rod with absorber

    NASA Astrophysics Data System (ADS)

    Xing, Mingming; Zhou, Lili; Kaifeng, Xue

    2017-03-01

    Considering the influence of sucker rod absorber (SRA) on longitudinal vibration of sucker rod string (SRS), a new model of mix sucker rod with absorber (MSRWA) in the form of numerical integration is built. In the detail, based on the dynamical theory of continuous systems, the wave equation of instantaneous motion of MSRWA is deduced. The dynamic response is solved out with the mode superposition method. The affecting factors of natural frequency are analyzed, such as the length, diameter, density and elastic modulus of SRS. Then three dimensional curves of natural frequency are obtained. The results are very important for the design and application of SRS.

  7. WBN-1 Cycle 10 TPBAR Tritium Release, Deduced From Analysis of RCS Data TTP-1-3046-00, Rev 0

    SciTech Connect

    Shaver, Mark W.; Niehus, Mark T.; Love, Edward F.

    2012-02-19

    This document contains the calculation of the TPBAR tritium release from the Mark 9.2 design TPBARs irradiated in WBN cycle 10. The calculation utilizes the generalized cycle analysis methodology given in TTP-1-3045 Rev. 0.

  8. Benchmark Evaluation of the HTR-PROTEUS Absorber Rod Worths (Core 4)

    SciTech Connect

    John D. Bess; Leland M. Montierth

    2014-06-01

    PROTEUS was a zero-power research reactor at the Paul Scherrer Institute (PSI) in Switzerland. The critical assembly was constructed from a large graphite annulus surrounding a central cylindrical cavity. Various experimental programs were investigated in PROTEUS; during the years 1992 through 1996, it was configured as a pebble-bed reactor and designated HTR-PROTEUS. Various critical configurations were assembled with each accompanied by an assortment of reactor physics experiments including differential and integral absorber rod measurements, kinetics, reaction rate distributions, water ingress effects, and small sample reactivity effects [1]. Four benchmark reports were previously prepared and included in the March 2013 edition of the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhEP Handbook) [2] evaluating eleven critical configurations. A summary of that effort was previously provided [3] and an analysis of absorber rod worth measurements for Cores 9 and 10 have been performed prior to this analysis and included in PROTEUS-GCR-EXP-004 [4]. In the current benchmark effort, absorber rod worths measured for Core Configuration 4, which was the only core with a randomly-packed pebble loading, have been evaluated for inclusion as a revision to the HTR-PROTEUS benchmark report PROTEUS-GCR-EXP-002.

  9. Influence of absorbed pump profile on the temperature distribution within a diode side-pumped laser rod

    NASA Astrophysics Data System (ADS)

    Moghtader Dindarlu, M. H.; Tehrani, M. Kavosh; Saghafifar, H.; Maleki, A.; Solookinejad, Gh; Jabbari, M.

    2017-02-01

    In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated. Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile.

  10. Surgical Fixation of Fourth and Fifth Metacarpal Shaft Fractures with Flexible Intramedullary Absorbable Rods: Early Clinical Outcomes and Implications

    PubMed Central

    Xiong, Ge; Xiao, Zi-Run; Guo, Shi-Gong; Zheng, Wei; Dai, Lu-Fei

    2015-01-01

    Background: To avoid the irritation of tendons and soft tissues as well as hardware-related problems, we designed an intramedullary fixation with bioabsorbable rods for the treatment of the metacarpal shaft fractures. Methods: Five patients with nine shaft fractures of the fourth and fifth metacarpi were treated with intramedullary absorbable implants and followed up with an average of 4.2 months postoperatively. Results: At final follow-up, all patients achieved fracture union with no signs of inflammatory or subcutaneous effusion. There was no shortening, angulatory, or rotatory deformity. There was almost full active extension range of motion (ROM) of the metacarpophalangeal joints while the active flexion ROM of these joints was 80.7 ± 9.6°. Compared with the contralateral hand, the grip strength of the injured hand was 94.0 ± 9.6%. X-rays showed that the arch of the second to fifth metacarpal heads was smooth. There were no intramedullary lytic changes and soft tissue swellings. Conclusion: The intramedullary absorbable implants are a safe, simple, and practical treatment for fourth and fifth metacarpal fractures with good early clinical outcomes and no significant complications. PMID:26521780

  11. Development of a Remotely Operated Band Saw for the Tritium Extraction Facility

    SciTech Connect

    Gordon, J

    2001-01-10

    Future tritium production will be accomplished by irradiation of Tritium Producing Burnable Absorber Rods (TPBARs) in a pressurized water reactor (PWR). The highly radioactive TPBARs will be shipped from the PWR to the Savannah River Site for processing. All processing operations will be accomplished remotely including preparation of the TPBARs for extraction by providing a vent path for the tritium. The Tritium Extraction Facility (TEF) will accomplish this breaching operation by using a remotely operated band saw. The development of the system necessary to breach the TPBARs is the focus of this paper.

  12. Controllable synthesis and enhanced microwave absorbing properties of Fe3O4/NiFe2O4/Ni heterostructure porous rods

    NASA Astrophysics Data System (ADS)

    Li, Yana; Wu, Tong; Jin, Keying; Qian, Yao; Qian, Naxin; Jiang, Kedan; Wu, Wenhua; Tong, Guoxiu

    2016-11-01

    We developed a coordinated self-assembly/precipitate transfer/sintering method that allows the controllable synthesis of Fe3O4/NiFe2O4/Ni heterostructure porous rods (HPRs). A series of characterizations confirms that changing [Ni2+] can effectively control the crystal size, internal strain, composition, textural characteristics, and properties of HPRs. Molar percentages of Ni and NiFe2O4 in HPRs increase with [Ni2+] in various Boltzmann function modes. Saturation magnetization Ms and coercivity Hc show U-shaped change trends because of crystal size, composition, and interface magnetic coupling. High magnetic loss is maintained after decorating NiFe2O4 and Ni on the surface of Fe3O4 PRs. Controlling the NiFe2O4 interface layers and Ni content can improve impedance matching and dielectric losses, thereby leading to lighter weight, stronger absorption, and broader absorption band of Fe3O4/NiFe2O4/Ni HPRs than Fe3O4 PRs. An optimum EM wave absorbing property was exhibited by Fe3O4/NiFe2O4/Ni HPRs formed at [Ni2+] = 0.05 M. The maximum reflection loss (RL) reaches -58.4 dB at 13.68 GHz, which corresponds to a 2.1 mm matching thickness. The absorbing bandwidth (RL ≤ -20 dB) reaches 14.4 GHz with the sample thickness at 1.6-2.4 and 2.8-10.0 mm. These excellent properties verify that Fe3O4/NiFe2O4/Ni HPRs are promising candidates for new and effective absorptive materials.

  13. CONTROL ROD

    DOEpatents

    Zinn, W.H.; Ross, H.V.

    1958-11-18

    A control rod is described for a nuclear reactor. In certaln reactor designs it becomes desirable to use a control rod having great width but relatively llttle thickness. This patent is addressed to such a need. The neutron absorbing material is inserted in a triangular tube, leaving volds between the circular insert and the corners of the triangular tube. The material is positioned within the tube by the use of dummy spacers to achleve the desired absorption pattern, then the ends of the tubes are sealed with suitable plugs. The tubes may be welded or soldered together to form two flat surfaces of any desired width, and covered with sheetmetal to protect the tubes from damage. This design provides a control member that will not distort under the action of outside forces or be ruptured by gases generated within the jacketed control member.

  14. Advanced gray rod control assembly

    DOEpatents

    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.

  15. Automatic safety rod for reactors

    DOEpatents

    Germer, John H.

    1988-01-01

    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-core 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.

  16. Internal absorber solar collector

    DOEpatents

    Sletten, Carlyle J.; Herskovitz, Sheldon B.; Holt, F. S.; Sletten, E. J.

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

  17. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    DOEpatents

    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.

  18. Automatic safety rod for reactors. [LMFBR

    DOEpatents

    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. CONTROL ROD

    DOEpatents

    Walker, D.E.; Matras, S.

    1963-04-30

    This patent shows a method of making a fuel or control rod for a nuclear reactor. Fuel or control material is placed within a tube and plugs of porous metal wool are inserted at both ends. The metal wool is then compacted and the tube compressed around it as by swaging, thereby making the plugs liquid- impervious but gas-pervious. (AEC)

  20. VARIABLE AREA CONTROL ROD FOR NUCLEAR REACTOR

    DOEpatents

    Huston, N.E.

    1960-05-01

    A control rod is described which permits continual variation of its absorbing strength uniformly along the length of the rod. The rod is fail safe and is fully inserted into the core but changes in its absorbing strength do not produce axial flux distortion. The control device comprises a sheet containing a material having a high thermal-neutron absorption cross section. A pair of shafts engage the sheet along the longitudinal axis of the shafts and gears associated with the shafts permit winding and unwinding of the sheet around the shafts.

  1. Shock absorber servicing tool

    NASA Technical Reports Server (NTRS)

    Koepler, Jack L. (Inventor); Hill, Robert L. (Inventor)

    1981-01-01

    A tool to assist in the servicing of a shock absorber wherein the shock absorber is constructed of a pair of aligned gas and liquid filled chambers. Each of the chambers is separated by a movable separator member. Maximum efficiency of the shock absorber is achieved in the locating of a precise volume of gas within the gas chamber and a precise volume of liquid within the liquid chamber. The servicing tool of this invention employs a rod which is to connect with the separator and by observation of the position of the rod with respect to the gauge body, the location of the separator is ascertained even though it is not directly observable.

  2. Apollo couch energy absorbers

    NASA Technical Reports Server (NTRS)

    Wesselski, C. J.; Drexel, R. E.

    1972-01-01

    Load attenuators for the Apollo spacecraft crew couch and its potential applications are described. Energy absorption is achieved through friction and cyclic deformation of material. In one concept, energy absorption is accomplished by rolling a compressed ring of metal between two surfaces. In another concept, energy is absorbed by forcing a plastically deformed washer along a rod. Among the design problems that had to be solved were material selection, fatigue life, ring slippage, lubrication, and friction loading.

  3. Rod examination gauge

    SciTech Connect

    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.

  4. FUEL ROD ASSEMBLY

    DOEpatents

    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. NNSA TRITIUM SUPPLY CHAIN

    SciTech Connect

    Wyrick, Steven; Cordaro, Joseph; Founds, Nanette; Chambellan, Curtis

    2013-08-21

    Savannah River Site plays a critical role in the Tritium Production Supply Chain for the National Nuclear Security Administration (NNSA). The entire process includes: • Production of Tritium Producing Burnable Absorber Rods (TPBARs) at the Westinghouse WesDyne Nuclear Fuels Plant in Columbia, South Carolina • Production of unobligated Low Enriched Uranium (LEU) at the United States Enrichment Corporation (USEC) in Portsmouth, Ohio • Irradiation of TPBARs with the LEU at the Tennessee Valley Authority (TVA) Watts Bar Reactor • Extraction of tritium from the irradiated TPBARs at the Tritium Extraction Facility (TEF) at Savannah River Site • Processing the tritium at the Savannah River Site, which includes removal of nonhydrogen species and separation of the hydrogen isotopes of protium, deuterium and tritium.

  6. ROD INTERNAL PRESSURE QUANTIFICATION AND DISTRIBUTION ANALYSIS USING FRAPCON

    SciTech Connect

    Ivanov, Kostadin; Jessee, Matthew Anderson

    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.

  7. Control rod drive

    SciTech Connect

    Hawke, Basil C.

    1986-01-01

    A control rod drive uses gravitational forces to insert one or more control rods upwardly into a reactor core from beneath the reactor core under emergency conditions. The preferred control rod drive includes a vertically movable weight and a mechanism operatively associating the weight with the control rod so that downward movement of the weight is translated into upward movement of the control rod. The preferred control rod drive further includes an electric motor for driving the control rods under normal conditions, an electrically actuated clutch which automatically disengages the motor during a power failure and a decelerator for bringing the control rod to a controlled stop when it is inserted under emergency conditions into a reactor core.

  8. Commercial Light Water Reactor -Tritium Extraction Facility Process Waste Assessment (Project S-6091)

    SciTech Connect

    Hsu, R.H.; Delley, A.O.; Alexander, G.J.; Clark, E.A.; Holder, J.S.; Lutz, R.N.; Malstrom, R.A.; Nobles, B.R.; Carson, S.D.; Peterson, P.K.

    1997-11-30

    The Savannah River Site (SRS) has been tasked by the Department of Energy (DOE) to design and construct a Tritium Extraction Facility (TEF) to process irradiated tritium producing burnable absorber rods (TPBARs) from a Commercial Light Water Reactor (CLWR). The plan is for the CLWR-TEF to provide tritium to the SRS Replacement Tritium Facility (RTF) in Building 233-H in support of DOE requirements. The CLWR-TEF is being designed to provide 3 kg of new tritium per year, from TPBARS and other sources of tritium (Ref. 1-4).The CLWR TPBAR concept is being developed by Pacific Northwest National Laboratory (PNNL). The TPBAR assemblies will be irradiated in a Commercial Utility light water nuclear reactor and transported to the SRS for tritium extraction and processing at the CLWR-TEF. A Conceptual Design Report for the CLWR-TEF Project was issued in July 1997 (Ref. 4).The scope of this Process Waste Assessment (PWA) will be limited to CLWR-TEF processing of CLWR irradiated TPBARs. Although the CLWR- TEF will also be designed to extract APT tritium-containing materials, they will be excluded at this time to facilitate timely development of this PWA. As with any process, CLWR-TEF waste stream characteristics will depend on process feedstock and contaminant sources. If irradiated APT tritium-containing materials are to be processed in the CLWR-TEF, this PWA should be revised to reflect the introduction of this contaminant source term.

  9. Piston rod seal

    DOEpatents

    Lindskoug, Stefan

    1984-01-01

    In a piston rod seal of the type comprising a gland through which the piston rod is passed the piston is provided with a sleeve surrounding the piston rod and extending axially so as to axially partly overlap the gland when the piston is in its bottom dead center position.

  10. CONTROL ROD DRIVE

    DOEpatents

    Chapellier, R.A.; Rogers, I.

    1961-06-27

    Accurate and controlled drive for the control rod is from an electric motor. A hydraulic arrangement is provided to balance a piston against which a control rod is urged by the application of fluid pressure. The electric motor drive of the control rod for normal operation is made through the aforementioned piston. In the event scramming is required, the fluid pressure urging the control rod against the piston is relieved and an opposite fluid pressure is applied. The lack of mechanical connection between the electric motor and control rod facilitates the scramming operation.

  11. Sucker rod construction

    SciTech Connect

    Anderson, R.A.; Goodman, J.L.; Tickle, J.D.; Liskey, A.K.

    1987-03-31

    A sucker rod construction is described comprising: a connector member being formed to define a rod receptacle having a closed axially inner end and an open axially outer end, the rod receptacle having axially spaced, tapered annular surfaces, a cylindrical fiberglass rod having an end having an outer surface being received within the rod receptacle through the outer end and cooperating therewith to define an annular chamber between the outer surface of the end of the rod and the tapered annular surfaces, and a bonding means positioned in the annular chamber for bonding to the outer surface of the end of the rod to confront the tapered annular surfaces, each annular surface having an angle of taper with respect to the outer surface of the fiberglass rod, and each angle of taper being progressively and uniformly less toward the open end by an amount between one and one-half degrees and two degrees, inclusive, and a collet connected to the connector member adjacent the open axially outer end of the rod receptacle and having an axial bore therethrough retaining the end of the rod in coaxial position within the rod receptacle.

  12. CRUCIFORM CONTROL ROD JOINT

    DOEpatents

    Thorp, A.G. II

    1962-08-01

    An invention is described which relates to nuclear reactor control rod components and more particularly to a joint between cruciform control rod members and cruciform control rod follower members. In one embodiment this invention provides interfitting crossed arms at adjacent ends of a control rod and its follower in abutting relation. This holds the members against relative opposite longitudinal movement while a compression member keys the arms against relative opposite rotation around a common axis. Means are also provided for centering the control rod and its follower on a common axis and for selectively releasing the control rod from its follower for the insertion of a replacement of the control rod and reuse of the follower. (AEC)

  13. Magnetically tunable metamaterial perfect absorber

    NASA Astrophysics Data System (ADS)

    Lei, Ming; Feng, Ningyue; Wang, Qingmin; Hao, Yanan; Huang, Shanguo; Bi, Ke

    2016-06-01

    A magnetically tunable metamaterial perfect absorber (MPA) based on ferromagnetic resonance is experimentally and numerically demonstrated. The ferrite-based MPA is composed of an array of ferrite rods and a metallic ground plane. Frequency dependent absorption of the ferrite-based MPA under a series of applied magnetic fields is discussed. An absorption peak induced by ferromagnetic resonance appears in the range of 8-12 GHz under a certain magnetic field. Both the simulated and experimental results demonstrate that the absorption frequency of the ferrite-based MPA can be tuned by the applied magnetic field. This work provides an effective way to fabricate the magnetically tunable metamaterial perfect absorber.

  14. CONTROL ROD DRIVE

    DOEpatents

    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.

  15. Energy-Absorbing, Lightweight Wheels

    NASA Technical Reports Server (NTRS)

    Waydo, Peter

    2003-01-01

    Improved energy-absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways that result in lighter weights and more effective reduction of stresses generated by ground/wheel contact forces. These wheels could be made of metals and/or composite materials to withstand the expected extreme operating conditions. As shown in the figure, a wheel according to this concept would include an isogrid tire connected to a hub via spring rods. The isogrid tire would be a stiff, lightweight structure typically made of aluminum. The isogrid aspect of the structure would both impart stiffness and act as a traction surface. The hub would be a thin-walled body of revolution having a simple or compound conical or other shape chosen for structural efficiency. The spring rods would absorb energy and partially isolate the hub and the supported vehicle from impact loads. The general spring-rod configuration shown in the figure was chosen because it would distribute contact and impact loads nearly evenly around the periphery of the hub, thereby helping to protect the hub against damage that would otherwise be caused by large loads concentrated onto small portions of the hub.

  16. Rodded shutdown system for a nuclear reactor

    DOEpatents

    Golden, Martin P.; Govi, Aldo R.

    1978-01-01

    A top mounted nuclear reactor diverse rodded shutdown system utilizing gas fed into a pressure bearing bellows region sealed at the upper extremity to an armature. The armature is attached to a neutron absorber assembly by a series of shafts and connecting means. The armature is held in an uppermost position by an electromagnet assembly or by pressurized gas in a second embodiment. Deenergizing the electromagnet assembly, or venting the pressurized gas, causes the armature to fall by the force of gravity, thereby lowering the attached absorber assembly into the reactor core.

  17. FUEL ROD CLUSTERS

    DOEpatents

    Schultz, A.B.

    1959-08-01

    A cluster of nuclear fuel rods and a tubular casing therefor through which a coolant flows in heat-exchange contact with the fuel rods is described. The fuel rcds are held in the casing by virtue of the compressive force exerted between longitudinal ribs of the fuel rcds and internal ribs of the casing or the internal surfaces thereof.

  18. Hybrid nuclear reactor grey rod to obtain required reactivity worth

    DOEpatents

    Miller, John V.; Carlson, William R.; Yarbrough, Michael B.

    1991-01-01

    Hybrid nuclear reactor grey rods are described, wherein geometric combinations of relatively weak neutron absorber materials such as stainless steel, zirconium or INCONEL, and relatively strong neutron absorber materials, such as hafnium, silver-indium cadmium and boron carbide, are used to obtain the reactivity worths required to reach zero boron change load follow. One embodiment includes a grey rod which has combinations of weak and strong neutron absorber pellets in a stainless steel cladding. The respective pellets can be of differing heights. A second embodiment includes a grey rod with a relatively thick stainless steel cladding receiving relatively strong neutron absorber pellets only. A third embodiment includes annular relatively weak netron absorber pellets with a smaller diameter pellet of relatively strong absorber material contained within the aperture of each relatively weak absorber pellet. The fourth embodiment includes pellets made of a homogeneous alloy of hafnium and a relatively weak absorber material, with the percentage of hafnium chosen to obtain the desired reactivity worth.

  19. Control rod heterogeneity effects in liquid-metal fast breeder reactors: Method developments and experimental validation

    SciTech Connect

    Carta, M.; Granget, G.; Palmiotti, G.; Salvatores, M.; Soule, R.

    1988-11-01

    The control rod worth assessment in a large liquid-metal fast breeder reactor is strongly dependent on the actual arrangement of the absorber pins inside the control rod subassemblies. The so-called heterogeneity effects (i.e., the effects on the rod reactivity of the actual rod internal geometry versus homogenization of the absorber atoms over all the subassembly volume) have been evaluated, using explicit and variational methods to derive appropriate cross sections. An experimental program performed at the MASURCA facility has been used to validate these methods.

  20. High temperature control rod assembly

    DOEpatents

    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.

  1. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  2. Investigating the optical XNOR gate using plasmonic nano-rods

    NASA Astrophysics Data System (ADS)

    Akhlaghi, Majid; Kaboli, Milad

    2016-04-01

    In this paper, a coherent perfect absorption (CPA)-type XNOR gate based on plasmonic nano particle is proposed. It consists of two plasmonic nano rod arrays on top of two parallel arms with quartz substrate. The operation principle is based on the absorbable formation of a conductive path in the dielectric layer of a plasmonic nano-particles waveguide. Since the CPA efficiency depends strongly on the number of plasmonic nano-rod and the nano rod location, an efficient binary optimization method based the Particle Swarm Optimization (PSO) algorithm is used to design an optimized array of the plasmonic nano-rod in order to achieve the maximum absorption coefficient in the 'off' state and the minimum absorption coefficient in the 'on' state. In Binary PSO (BPSO), a group of birds consists a matrix with binary entries, control the presence ('1‧) or the absence ('0‧) of nano rod in the array.

  3. Control rod driveline and grapple

    DOEpatents

    Germer, John H.

    1987-01-01

    A control rod driveline and grapple is disclosed for placement between a control rod drive and a nuclear reactor control rod containing poison for parasitic neutron absorption required for reactor shutdown. The control rod is provided with an enlarged cylindrical handle which terminates in an upwardly extending rod to provide a grapple point for the driveline. The grapple mechanism includes a tension rod which receives the upwardly extending handle and is provided with a lower annular flange. A plurality of preferably six grapple segments surround and grip the control rod handle. Each grapple rod segment grips the flange on the tension rod at an interior upper annular indentation, bears against the enlarged cylindrical handle at an intermediate annulus and captures the upwardly flaring frustum shaped handle at a lower and complementary female segment. The tension rods and grapple segments are surrounded by and encased within a cylinder. The cylinder terminates immediately and outward extending annulus at the lower portion of the grapple segments. Excursion of the tension rod relative to the encasing cylinder causes rod release at the handle by permitting the grapple segments to pivot outwardly and about the annulus on the tension rod so as to open the lower defined frustum shaped annulus and drop the rod. Relative movement between the tension rod and cylinder can occur either due to electromagnetic release of the tension rod within defined limits of travel or differential thermal expansion as between the tension rod and cylinder as where the reactor exceeds design thermal limits.

  4. How to build a molecular shock absorber.

    PubMed

    McGough, A

    1999-12-02

    Newly determined structures of the alpha-helical repeats that make up the key 'rod' domains of spectrin and alpha-actinin - which serve as spacers between their actin-binding domains - have provided important insights into how these proteins function as molecular shock absorbers in cells.

  5. Rod Contributions to Color Perception: Linear with Rod Contrast

    PubMed Central

    Cao, Dingcai; Pokorny, Joel; Smith, Vivianne C.; Zele, Andrew J.

    2008-01-01

    At mesopic light levels, an incremental change in rod activation causes changes in color appearance. In this study, we investigated how rod mediated changes in color perception varied as a function of the magnitude of the rod contrast. Rod-mediated changes in color appearance were assessed by matching them with cone-mediated color changes. A two-channel four-primary colorimeter allowed independent control of the rods and each of the L-, M- and S-cone photoreceptor types. At all light levels, rod contributions to inferred PC, KC and MC pathway mediated vision were linearly related to the rod incremental contrast. This linear relationship could be described by a model based on primate ganglion cell responses with the assumption that rod signals were conveyed via rod-cone gap junctions at mesopic light levels. PMID:18561973

  6. Evidence for rod-shaped DNA-stabilized silver nanocluster emitters.

    PubMed

    Schultz, Danielle; Gardner, Kira; Oemrawsingh, Sumant S R; Markešević, Nemanja; Olsson, Kevin; Debord, Mark; Bouwmeester, Dirk; Gwinn, Elisabeth

    2013-05-28

    Fluorescent DNA-stabilized silver nanoclusters contain both cationic and neutral silver atoms. The absorbance spectra of compositionally pure solutions follow the trend expected for rod-shaped silver clusters, consistent with the polarized emission measured from individual nanoclusters. The data suggest a rod-like assembly of silver atoms, with silver cations mediating attachment to the bases.

  7. Intramedullary rodding in osteogenesis imperfecta.

    PubMed

    Mulpuri, K; Joseph, B

    2000-01-01

    The results of intramedullary rodding of long bones of 16 children with osteogenesis imperfecta, over a 10-year period, were analyzed. Sheffield elongating rods or non-elongating rods were used. The frequency of fractures was dramatically reduced after implantation of either type of rod, and the ambulatory status improved in all instances. The results were significantly better after Sheffield rodding with regard to the frequency of complications requiring reoperations and the longevity of the rods. Migration of the rods, encountered frequently, appears to be related to improper placement of the rods in the bone. It seems likely that if care is taken to ensure precise placement of a rod of appropriate size, several of these complications may be avoided.

  8. REACTOR CONTROL ROD OPERATING SYSTEM

    DOEpatents

    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)

  9. Learning with Rods: One Account.

    ERIC Educational Resources Information Center

    Cherry, Donald Esha

    This paper discusses one English as a Second Language (ESL) teacher's attempts to use cuisenaire rods as a language learning tool. Cuisenaire rods (sometimes called algebricks) vary in size from 1 x 1 x 10 centimeter sticks to 1 x 1 x 1 centimeter cubes, with each of the 10 sizes a different color. Although such rods have been used to teach…

  10. Deep-sea and pelagic rod visual pigments identified in the mysticete whales.

    PubMed

    Bischoff, Nicole; Nickle, Benjamin; Cronin, Thomas W; Velasquez, Stephani; Fasick, Jeffry I

    2012-03-01

    Our current understanding of the spectral sensitivities of the mysticete whale rod-based visual pigments is based on two species, the gray whale (Eschrichtius robustus) and the humpback whale (Megaptera novaeangliae) possessing absorbance maxima determined from difference spectra to be 492 and 497 nm, respectively. These absorbance maxima values are blueshifted relative to those from typical terrestrial mammals (≈500 nm) but are redshifted when compared to those identified in the odontocetes (479-484 nm). Although these mysticete species represent two of the four mysticete families, they do not fully represent the mysticete whales in terms of foraging strategy and underwater photic environments where foraging occurs. In order to better understand the spectral sensitivities of the mysticete whale rod visual pigments, we have examined the rod opsin genes from 11 mysticete species and their associated amino acid substitutions. Based on the amino acids occurring at positions 83, 292, and 299 along with the directly determined dark spectra from expressed odontocete and mysticete rod visual pigments, we have determined that the majority of mysticete whales possess deep-sea and pelagic like rod visual pigments with absorbance maxima between 479 and 484 nm. Finally, we have defined the five amino acid substitution events that determine the resulting absorbance spectra and associated absorbance maxima for the mysticete whale rod visual pigments examined here.

  11. Locked-wrap fuel rod

    DOEpatents

    Kaplan, Samuel; Chertock, Alan J.; Punches, James R.

    1977-01-01

    A method for spacing fast reactor fuel rods using a wire wrapper improved by orienting the wire-wrapped fuel rods in a unique manner which introduces desirable performance characteristics not attainable by previous wire-wrapped designs. Use of this method in a liquid metal fast breeder reactor results in: (a) improved mechanical performance, (b) improved rod-to-rod contact, (c) reduced steel volume, and (d) improved thermal-hydraulic performance. The method produces a "locked wrap" design which tends to lock the rods together at each of the wire cluster locations.

  12. SAFETY SYSTEM FOR CONTROL ROD

    DOEpatents

    Paget, J.A.

    1963-05-14

    A structure for monitoring the structural continuity of a control rod foi a neutron reactor is presented. A electric conductor readily breakable under mechanical stress is fastened along the length of the control rod at a plurality of positions and forms a closed circuit with remote electrical components responsive to an open circuit. A portion of the conductor between the control rod and said components is helically wound to allow free and normally unrestricted movement of the segment of conductor secured to the control rod relative to the remote components. Any break in the circuit is indicative of control rod breakage. (AEC)

  13. Trunnion Rod Microcrack Detection

    DTIC Science & Technology

    2013-08-01

    optimization, which can involve specification of frequency, propagation mode, transmitter, receiver, and post processing . More detail is presented...structures such as plates, rods, pipes and even more arbitrary shaped extrusions like railroad tracks, greatly affect the propagation characteristics of...waves exist only in solids and are not carried in fluids. Some greases do have limited capacity in carrying shear waves. Because the viscosity of some

  14. Safety rod latch inspection

    SciTech Connect

    Leader, D.R.

    1992-02-01

    During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small ``button`` in the latch mechanism had broken off of the ``lock plunger`` and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

  15. Safety rod latch inspection

    SciTech Connect

    Leader, D.R.

    1992-02-01

    During an attempt to raise control rods from the 100 K reactor in December, one rod could not be withdrawn. Subsequent investigation revealed that a small button'' in the latch mechanism had broken off of the lock plunger'' and was wedged in a position that prevented rod withdrawal. Concern that this failure may have resulted from corrosion or some other metallurgical problem resulted in a request that SRL examine six typical latch mechanisms from the 100 L reactor by use of radiography and metallography. During the examination of the L-Area latches, a failed latch mechanism from the 100 K reactor was added to the investigation. Fourteen latches that had a history of problems were removed from K-Area and sent to SRL for inclusion in this study the week after the original seven assemblies were examined, bringing the total of latch assemblies discussed in this report to twenty one. Results of the examination of the K-Area latch that initiated this study is not included in this report.

  16. ELECTROMAGNETIC APPARATUS FOR MOVING A ROD

    DOEpatents

    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.

  17. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  18. Reactor control rod timing system

    DOEpatents

    Wu, Peter T. K.

    1982-01-01

    A fluid driven jet-edge whistle timing system for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

  19. Making Highly Pure Glass Rods

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.

    1986-01-01

    Proposed quasi-containerless method for making glass rods or fibers minimizes contact between processing equipment and product. Method allows greater range of product sizes and shapes than achieved in experiments on containerless processing. Molten zone established in polycrystalline rod. Furnace sections separated, and glass rod solidifies between them. Clamp supports solid glass as it grows in length. Pulling clamp rapidly away from melt draws glass fiber. Fiber diameter controlled by adjustment of pulling rate.

  20. Active Brownian rods

    NASA Astrophysics Data System (ADS)

    Peruani, Fernando

    2016-11-01

    Bacteria, chemically-driven rods, and motility assays are examples of active (i.e. self-propelled) Brownian rods (ABR). The physics of ABR, despite their ubiquity in experimental systems, remains still poorly understood. Here, we review the large-scale properties of collections of ABR moving in a dissipative medium. We address the problem by presenting three different models, of decreasing complexity, which we refer to as model I, II, and III, respectively. Comparing model I, II, and III, we disentangle the role of activity and interactions. In particular, we learn that in two dimensions by ignoring steric or volume exclusion effects, large-scale nematic order seems to be possible, while steric interactions prevent the formation of orientational order at large scales. The macroscopic behavior of ABR results from the interplay between active stresses and local alignment. ABR exhibit, depending on where we locate ourselves in parameter space, a zoology of macroscopic patterns that ranges from polar and nematic bands to dynamic aggregates.

  1. Piston and connecting rod assembly

    NASA Technical Reports Server (NTRS)

    Brogdon, James William (Inventor); Gill, David Keith (Inventor); Chatten, John K. (Inventor)

    2001-01-01

    A piston and connecting rod assembly includes a piston crown, a piston skirt, a connecting rod, and a bearing insert. The piston skirt is a component separate from the piston crown and is connected to the piston crown to provide a piston body. The bearing insert is a component separate from the piston crown and the piston skirt and is fixedly disposed within the piston body. A bearing surface of a connecting rod contacts the bearing insert to thereby movably associate the connecting rod and the piston body.

  2. Sucker rod pump

    SciTech Connect

    Brewer, J.R.

    1992-04-14

    This patent describes a subsurface well pump, it comprises: a working barrel; a plunger which reciprocates along the vertical axis within the working barrel between an upper and lower position; a rod connected to the plunger and extending to a means for providing reciprocating force; a well string extending from the top of the working barrel to the surface; an outlet check valve which permits flow to exit the working barrel into the well string and does not permit flow to exit the well string into the working barrel; and an inlet check valve which permits flow into the working barrel from outside of the subsurface pump, the inlet check valve being above the top position of the plunger, the inlet check valve having a cross sectional flow area about equal to or greater than the horizontal cross sectional area of the working barrel, and the inlet check valve being a hinged flapper valve.

  3. Cuisenaire Rods Go to College.

    ERIC Educational Resources Information Center

    Chinn, Phyllis; And Others

    1992-01-01

    Presents examples of questions and answers arising from a hands-on and exploratory approach to discrete mathematics using cuisenaire rods. Combinatorial questions about trains formed of cuisenaire rods provide the setting for discovering numerical patterns by experimentation and organizing the results using induction and successive differences.…

  4. Topological mixing with ghost rods.

    PubMed

    Gouillart, Emmanuelle; Thiffeault, Jean-Luc; Finn, Matthew D

    2006-03-01

    Topological chaos relies on the periodic motion of obstacles in a two-dimensional flow in order to form nontrivial braids. This motion generates exponential stretching of material lines, and hence efficient mixing. Boyland, Aref, and Stremler [J. Fluid Mech. 403, 277 (2000)] have studied a specific periodic motion of rods that exhibits topological chaos in a viscous fluid. We show that it is possible to extend their work to cases where the motion of the stirring rods is topologically trivial by considering the dynamics of special periodic points that we call "ghost rods", because they play a similar role to stirring rods. The ghost rods framework provides a new technique for quantifying chaos and gives insight into the mechanisms that produce chaos and mixing. Numerical simulations for Stokes flow support our results.

  5. Experiments with a falling rod

    NASA Astrophysics Data System (ADS)

    Oliveira, Vitor

    2016-02-01

    We study the motion of a uniform thin rod released from rest, with the bottom end initially in contact with a horizontal surface. Our focus here is the motion of the bottom end as the rod falls. For small angles of release with respect to the horizontal, the rod falls without the bottom end slipping. For larger angles, the slipping direction depends on the static friction coefficient between the rod and the horizontal surface. Small friction coefficients cause the end to slip initially in one direction and then in the other, while for high coefficients, the end slips in one direction only. For intermediate values, depending on the angle of release, both situations can occur. We find the initial slipping direction to depend on a relation between the angle at which the rod slips, and a critical angle at which the frictional force vanishes. Comparison between experimental data and numerical simulations shows good agreement.

  6. Rushton's paradox: rod dark adaptation after flash photolysis.

    PubMed Central

    Pugh, E N

    1975-01-01

    1. Rod dark adaptations after a photoregenerating flash and quantum-equivalent 30 sec bleach are found to be in exact agreement, while the measured rhodopsin regenerations are grossly different. This finding confirms and clarifies "Rushton's paradox', the failure of the Dowling-Rushton equation (linking log sensitivity linearly with unregenerated rhodopsin) to account for human rod dark adaptation after flash photolysis. 2. The hypothesis that the agreement between rod dark adaptation curves after a photoregenerating flash and after a quantum-equivalent 30 sec bleach is coincidental is rejected on the basic of two classes of experiments. 3. Rod "bleaching' adaptation is demonstrated to be entirely determined by the number of rhodopsin molecules which absorb at least one quantum in a temporal period T, whose range includes the time interval 600 musec less than or equal T less than or equal 30 sec. This generalization obtains over the entire scotopic energy range (congruent to 3 log units) where rod dark adaptations has been studied. 4. Thus, the state of "bleaching' adaptation is determined by some by-product of the normal chain of events in scotopic excitation. About this by-product three important deductions are made: (i) its production is a monotonic function of the initial effective quantum absorptions; (ii) its production occurs before the metarhodopsin I leads to to metarhodopsin II dark reaction; (iii) it cannot be any photoproduct of the rhodopsin cycle. PMID:1151791

  7. Nuclear reactor shutdown control rod assembly

    DOEpatents

    Bilibin, Konstantin

    1988-01-01

    A temperature responsive, self-actuated nuclear reactor shutdown control rod assembly 10. The upper end 18 of a lower drive line 17 fits within the lower end of an upper drive line 12. The lower end (not shown) of the lower drive line 17 is connected to a neutron absorber. During normal temperature conditions the lower drive line 17 is supported by detent means 22,26. When an overtemperature condition occurs thermal actuation means 34 urges ring 26 upwardly sufficiently to allow balls 22 to move radially outwardly thereby allowing lower drive line 17 to move downwardly toward the core of the nuclear reactor resulting in automatic reduction of the reactor powder.

  8. Rod internal pressure quantification and distribution analysis using Frapcon

    SciTech Connect

    Bratton, Ryan N; Jessee, Matthew Anderson; Wieselquist, William A

    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

  9. Topological mixing with ghost rods

    NASA Astrophysics Data System (ADS)

    Gouillart, Emmanuelle; Thiffeault, Jean-Luc; Finn, Matthew D.

    2006-03-01

    Topological chaos relies on the periodic motion of obstacles in a two-dimensional flow in order to form nontrivial braids. This motion generates exponential stretching of material lines, and hence efficient mixing. Boyland, Aref, and Stremler [J. Fluid Mech. 403, 277 (2000)] have studied a specific periodic motion of rods that exhibits topological chaos in a viscous fluid. We show that it is possible to extend their work to cases where the motion of the stirring rods is topologically trivial by considering the dynamics of special periodic points that we call “ghost rods”, because they play a similar role to stirring rods. The ghost rods framework provides a new technique for quantifying chaos and gives insight into the mechanisms that produce chaos and mixing. Numerical simulations for Stokes flow support our results.

  10. Hydrothermal synthesis of hydroxyapatite rods

    NASA Astrophysics Data System (ADS)

    Zhang, Xing; Vecchio, Kenneth S.

    2007-10-01

    Hydroxyapatite (HAP) rods were synthesized from dicalcium phosphate anhydrous (CaHPO 4, DCPA) and calcium carbonate (CaCO 3) by the hydrothermal method from 120 to 180 °C. Both cuttlebone (aragonite polymorph of CaCO 3) and CaCO 3 chemical (calcite polymorph of CaCO 3) were used as CaCO 3 sources. The nucleation and growth of HAP rods mainly occurred on DCPA particles, while some HAP rods also grew from aragonite particles. The nucleation and growth of β-tricalcium phosphate (β-TCP) particles on the surface of calcite particles were observed at the beginning of the reaction of DCPA and calcite, and some HAP rods were also found to grow out of β-TCP particles. After the hydrothermal reaction at 140 °C for 24 h, most products are HAP with a small amount of β-TCP synthesized as a byproduct. The HAP rods synthesized were ˜200 nm in width and several microns in length. The reaction mechanism and growth process of HAP rods are discussed.

  11. Nuclear design of Helical Cruciform Fuel rods

    SciTech Connect

    Shirvan, K.; Kazimi, M. S.

    2012-07-01

    In order to increase the power density of current and new light water reactor designs, the Helical Cruciform Fuel (HCF) rods are proposed. The HCF rods are equivalent to a cylindrical rod, with the fuel in a cruciform shaped, twisted axially. The HCF rods increase the surface area to volume ratio and inter-subchannel mixing behavior due to their cruciform and helical shapes, respectively. In a previous study, the HCF rods have shown the potential to up-rate existing PWRs by 50% and BWRs by 25%. However, HCF rods do display different neutronics modeling and performance. The cruciform cross section of HCF rods creates radially asymmetric heat generation and temperature distribution. The nominal HCF rod's beginning of life reactivity is reduced, compared to a cylindrical rod with the same fuel volume, by 500 pcm, due to increase in absorption in cladding. The rotation of these rods accounts for reactivity changes, which depends on the H/HM ratio of the pin cell. The HCF geometry shows large sensitivities to U{sup 235} or gadolinium enrichments compared to a cylindrical geometry. In addition, the gadolinium-containing HCF rods show a stronger effect on neighboring HCF rods than in case of cylindrical rods, depending on the orientation of the HCF rods. The helical geometry of the rods introduces axial shadowing of about 600 pcm, not seen in typical cylindrical rods. (authors)

  12. Composition for absorbing hydrogen

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Enz, Glenn L.

    1995-01-01

    A hydrogen absorbing composition. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  13. Composition for absorbing hydrogen

    DOEpatents

    Heung, L.K.; Wicks, G.G.; Enz, G.L.

    1995-05-02

    A hydrogen absorbing composition is described. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  14. Piston-rotaxanes as molecular shock absorbers.

    PubMed

    Sevick, E M; Williams, D R M

    2010-04-20

    We describe the thermomechanical response of a new molecular system that behaves as a shock absorber. The system consists of a rodlike rotaxane connected to a piston and tethered to a surface. The response of this system is dominated by the translational entropy of the rotaxane rings and can be calculated exactly. The force laws are contrasted with those for a rigid rod and a polymer. In some cases, the rotaxanes undergo a sudden transition to a tilted state when compressed. These piston-rotaxanes provide a potential motif for the design of a new class of materials with a novel thermomechanical response.

  15. Behavior of Segmented Rods during Penetration

    DTIC Science & Technology

    1990-07-01

    full-scale penetrators which had been swaged 24%. The density of this tungsten alloy was 17.2 Mg/m 3. Gold-alloy penetrators were composed of 92Au-4.9Ag...of behavior. Segmented rods of tungsten alloy always penetrated less than the equivalent unitary rod. Successive rod segments were found to...gold-alloy penetrators because unitary rods of this material surpassed the perform- ance of unitary tungsten -alloy rods, while leaving almost no

  16. NEUTRONIC REACTOR CONTROL ROD DRIVE APPARATUS

    DOEpatents

    Oakes, L.C.; Walker, C.S.

    1959-12-15

    ABS>A suspension mechanism between a vertically movable nuclear reactor control rod and a rod extension, which also provides information for the operator or an automatic control signal, is described. A spring connects the rod extension to a drive shift. The extension of the spring indicates whether (1) the rod is at rest on the reactor, (2) the rod and extension are suspended, or (3) the extension alone is suspended, the spring controlling a 3-position electrical switch.

  17. The evolution of rod photoreceptors.

    PubMed

    Morshedian, Ala; Fain, Gordon L

    2017-04-05

    Photoreceptors in animals are generally of two kinds: the ciliary or c-type and the rhabdomeric or r-type. Although ciliary photoreceptors are found in many phyla, vertebrates seem to be unique in having two distinct kinds which together span the entire range of vision, from single photons to bright light. We ask why the principal photoreceptors of vertebrates are ciliary and not rhabdomeric, and how rods evolved from less sensitive cone-like photoreceptors to produce our duplex retina. We suggest that the principal advantage of vertebrate ciliary receptors is that they use less ATP than rhabdomeric photoreceptors. This difference may have provided sufficient selection pressure for the development of a completely ciliary eye. Although many of the details of rod evolution are still uncertain, present evidence indicates that (i) rods evolved very early before the split between the jawed and jawless vertebrates, (ii) outer-segment discs make no contribution to rod sensitivity but may have evolved to increase the efficiency of protein renewal, and (iii) evolution of the rod was incremental and multifaceted, produced by the formation of several novel protein isoforms and by changes in protein expression, with no one alteration having more than a few-fold effect on transduction activation or inactivation.This article is part of the themed issue 'Vision in dim light'.

  18. Externally tuned vibration absorber

    DOEpatents

    Vincent, Ronald J.

    1987-09-22

    A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

  19. Shock absorber control system

    SciTech Connect

    Nakano, Y.; Ohira, M.; Ushida, M.; Miyagawa, T.; Shimodaira, T.

    1987-01-13

    A shock absorber control system is described for controlling a dampening force of a shock absorber of a vehicle comprising: setting means for setting a desired dampening force changeable within a predetermined range; drive means for driving the shock absorber to change the dampening force of the shock absorber linearly; control means for controlling the drive means in accordance with the desired dampening force when the setting of the desired dampening force has been changed; detecting means for detecting an actual dampening force of the shock absorber; and correcting means for correcting the dampening force of the shock absorber by controlling the drive means in accordance with a difference between the desired dampening force and the detected actual dampening force.

  20. CPCs with segmented absorbers

    SciTech Connect

    Keita, M.; Robertson, H.S. )

    1991-01-01

    One of the most promising means of improving the performance of solar thermal collectors is to reduce the energy lost by the hot absorber. One way to do this, not currently part of the technology, is to recognize that since the absorber is usually not irradiated uniformly, it is therefore possible to construct an absorber of thermally isolated segments, circulate the fluid in sequence from low to high irradiance segments, and reduce loss by improving effective concentration. This procedure works even for ideal concentrators, without violating Winston's theorem. Two equivalent CPC collectors with single and segmented absorber were constructed and compared under actual operating conditions. The results showed that the daily thermal efficiency of the collector with segmented absorber is higher (about 13%) than that of the collector with nonsegmented absorber.

  1. Methods for absorbing neutrons

    DOEpatents

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  2. Topological Optimization of Rod Mixers

    NASA Astrophysics Data System (ADS)

    Finn, Matthew D.; Thiffeault, Jean-Luc

    2006-11-01

    Stirring of fluid with moving rods is necessary in many practical applications to achieve homogeneity. These rods are topological obstacles that force stretching of fluid elements. The resulting stretching and folding is commonly observed as filaments and striations, and is a precursor to mixing. In a space-time diagram, the trajectories of the rods form a braid [1], and the properties of this braid impose a minimal complexity in the flow. We discuss how optimal mixing protocols can be obtained by a judicious choice of braid, and how these protocols can be implemented using simple gearing [2].[12pt] [1] P. L. Boyland, H. Aref, and M. A. Stremler, JFM 403, 277 (2000).[8pt] [2] J.-L. Thiffeault and M. D. Finn, http://arxiv.org/nlin/0603003

  3. Stuck fuel rod capping sleeve

    DOEpatents

    Gorscak, Donald A.; Maringo, John J.; Nilsen, Roy J.

    1988-01-01

    A stuck fuel rod capping sleeve to be used during derodding of spent fuel assemblies if a fuel rod becomes stuck in a partially withdrawn position and, thus, has to be severed. The capping sleeve has an inner sleeve made of a lower work hardening highly ductile material (e.g., Inconel 600) and an outer sleeve made of a moderately ductile material (e.g., 304 stainless steel). The inner sleeve may be made of an epoxy filler. The capping sleeve is placed on a fuel rod which is then severed by using a bolt cutter device. Upon cutting, the capping sleeve deforms in such a manner as to prevent the gross release of radioactive fuel material

  4. Reconstitutable control assembly having removable control rods with detachable split upper end plugs

    SciTech Connect

    Gjertsen, R.K.; Knott, R.P.; Sparrow, J.A.

    1991-02-19

    This patent describes, for use in facilitating replacement of a neutron absorber control rod on a control assembly spider structure, an end plug. It comprises a pair of separate upper and lower plug portions; the upper section of the upper plug portion being configured for rigid attachment; the middle section of the upper plug portion having angularly displaced flat surfaces formed on the exterior.

  5. Down hole shock absorber

    SciTech Connect

    Coston, H.A.

    1990-03-05

    This patent describes a well pump system. It comprises: a sucker rod string; a pump reciprocable in response to the string; a cylinder; a piston disposed for vertical reciprocal motion within the cylinder; means for biasing the cylinder and the piston against compressive motion; means for pneumatically relieving pressure in the cylinder during compressive motion; and means for preventing relative rotational motion and for limiting relative expansive motion between the cylinder and the piston; the cylinder and the piston being coaxially mounted in the sucker rod string proximate and above the pump to buffer forces transmitted through the string.

  6. Advanced neutron absorber materials

    DOEpatents

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  7. Multispectral metamaterial absorber.

    PubMed

    Grant, J; McCrindle, I J H; Li, C; Cumming, D R S

    2014-03-01

    We present the simulation, implementation, and measurement of a multispectral metamaterial absorber (MSMMA) and show that we can realize a simple absorber structure that operates in the mid-IR and terahertz (THz) bands. By embedding an IR metamaterial absorber layer into a standard THz metamaterial absorber stack, a narrowband resonance is induced at a wavelength of 4.3 μm. This resonance is in addition to the THz metamaterial absorption resonance at 109 μm (2.75 THz). We demonstrate the inherent scalability and versatility of our MSMMA by describing a second device whereby the MM-induced IR absorption peak frequency is tuned by varying the IR absorber geometry. Such a MSMMA could be coupled with a suitable sensor and formed into a focal plane array, enabling multispectral imaging.

  8. Control rods in LMFBRs: a physics assessment

    SciTech Connect

    McFarlane, H.F.; Collins, P.J.

    1982-08-01

    This physics assessment is based on roughly 300 control rod worth measurements in ZPPR from 1972 to 1981. All ZPPR assemblies simulated mixed-oxide LMFBRs, representing sizes of 350, 700, and 900 MWe. Control rod worth measurements included single rods, various combinations of rods, and Ta and Eu rods. Additional measurements studied variations in B/sub 4/C enrichment, rod interaction effects, variations in rod geometry, neutron streaming in sodium-filled channels, and axial worth profiles. Analyses were done with design-equivalent methods, using ENDF/B Version IV data. Some computations for the sensitivities to approximations in the methods have been included. Comparisons of these analyses with the experiments have allowed the status of control rod physics in the US to be clearly defined.

  9. Tritium Release Estimate from CLWR-Tritium Extraction Facility Waste Overpack

    SciTech Connect

    Clark, E.A.

    2001-05-23

    Spent targets (Tritium Producing Burnable Absorber Rods, TPBARs) from the Commercial Light Water Reactor-Tritium Extraction Facility (CLWR-TEF) at the Savannah River Site will be sent to waste disposal contained in a so-called ''overpack''. The tritium permeation rate through a welded stainless steel overpack was estimated using a finite difference computer program in a previous report. This report is an evaluation of tritium permeation through three additional overpack designs: (1) a stainless steel overpack sealed using a mechanical closure with a metal gasket, (2) a mild steel overpack with the same mechanical closure, and (3) an aluminum overpack sealed by welding.

  10. Solid-state-laser-rod holder

    DOEpatents

    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.

  11. Magnetically manipulable perfect unidirectional absorber based on nonreciprocal magnetic surface plasmon

    NASA Astrophysics Data System (ADS)

    Yu, Jingjing; Chen, Huajin; Wu, Yongbin; Liu, Shiyang

    2012-11-01

    We demonstrate a design of a perfect unidirectional absorber by constructing a magnetic metamaterial (MM) made of an array of ferrite rods. Near the magnetic surface plasmon (MSP) resonance an incident transverse magnetic (TM) Gaussian beam can be absorbed completely at a particular direction, while at the symmetrically opposite direction an obvious reflected beam is observed. This unidirectionality originates from the time reversal symmetry (TRS)-breaking nature of the MM, which can also be shown numerically by comparing the scattering amplitude of the partial waves in two opposite directions. In addition, the unidirectionality can be reversed by reversing the magnetization of the ferrite rods. The working frequency can be controlled as well by tuning the external magnetic field (EMF). Another merit of this absorber is the robustness against position and size disorders of the ferrite rods.

  12. Integrity of neutron-absorbing components of LWR fuel systems

    SciTech Connect

    Bailey, W.J.; Berting, F.M.

    1991-03-01

    A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs.

  13. Inverted Control Rod Lock-In Device

    DOEpatents

    Brussalis, W. G.; Bost, G. E.

    1962-12-01

    A mechanism which prevents control rods from dropping out of the reactor core in the event the vessel in which the reactor is mounted should capsize is described. The mechanism includes a pivoted toothed armature which engages the threaded control rod lead screw and prevents removal of the rod whenever the armature is not attracted by the provided electromagnetic means. (AEC)

  14. 21 CFR 876.4270 - Colostomy rod.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Colostomy rod. 876.4270 Section 876.4270 Food and... GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod is a device used during the loop colostomy procedure. A loop of colon is surgically brought out...

  15. Hydraulic Actuator for Ganged Control Rods

    NASA Technical Reports Server (NTRS)

    Thompson, D. C.; Robey, R. M.

    1986-01-01

    Hydraulic actuator moves several nuclear-reactor control rods in unison. Electromagnetic pump pushes liquid lithium against ends of control rods, forcing them out of or into nuclear reactor. Color arrows show lithium flow for reactor startup and operation. Flow reversed for shutdown. Conceived for use aboard spacecraft, actuator principle applied to terrestrial hydraulic machinery involving motion of ganged rods.

  16. Lipid-absorbing Polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Wallace, C. J.

    1973-01-01

    The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

  17. Electromagnetic power absorber

    NASA Technical Reports Server (NTRS)

    Iwasaki, R. S. (Inventor)

    1979-01-01

    A structure is presented with a surface portion of dielectric material which passes electromagnetic radiation and with a portion below the surface which includes material that absorbs the radiation, the face of the structure being formed with numerous steep ridges. The steepness of the dielectric material results in a high proportion of the electromagnetic energy passing through the surface for absorption by the absorbing material under the surface. A backing of aluminum or other highly heat-conductive and reflective material lies under the face and has very steep protuberances supporting the absorbing and dielectric materials.

  18. "Smart" Electromechanical Shock Absorber

    NASA Technical Reports Server (NTRS)

    Stokes, Lebarian; Glenn, Dean C.; Carroll, Monty B.

    1989-01-01

    Shock-absorbing apparatus includes electromechanical actuator and digital feedback control circuitry rather than springs and hydraulic damping as in conventional shock absorbers. Device not subject to leakage and requires little or no maintenance. Attenuator parameters adjusted in response to sensory feedback and predictive algorithms to obtain desired damping characteristic. Device programmed to decelerate slowly approaching vehicle or other large object according to prescribed damping characteristic.

  19. Exploiting rod technology. Final report

    SciTech Connect

    1990-06-01

    ROD development was proceeding apace until recent budgetary decisions caused funding support for ROD development to be drastically reduced. The funding which was originally provided by DARPA and the Balanced Technology Initiative (BTI) Office has been cut back to zero from $800K. To determine the aeroballistic coefficients of a candidate dart, ARDEC is currently supporting development out of its own 6.2 funds at about $100K. ARDEC has made slow progress toward achieving this end because of failures in the original dart during testing. It appears that the next dart design to be tested will diverge from the original concept visualized by DARPA and Science and Technology Associates (STA). STA, the design engineer, takes exception to these changes on the basis of inappropriate test conditions and insufficient testing. At this time, the full resolution of this issue will be difficult because of the current management structure, which separates the developer (ARDEC) from the designer (STA).

  20. Fuel rod assembly to manifold attachment

    DOEpatents

    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.

  1. Unidirectional perfect absorber

    PubMed Central

    Jin, L.; Wang, P.; Song, Z.

    2016-01-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices. PMID:27615125

  2. Unidirectional perfect absorber

    NASA Astrophysics Data System (ADS)

    Jin, L.; Wang, P.; Song, Z.

    2016-09-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices.

  3. Shock Absorbing System

    NASA Astrophysics Data System (ADS)

    1982-01-01

    A lightweight, inexpensive shock-absorbing system, developed by Langley Research Center 20 years ago, is now in service as safety device for an automated railway at Duke University Medical Center. The transportation system travels at about 25 miles per hour, carrying patients, visitors, staff and cargo. At the end of each guideway of the system are "frangible," (breakable) tube "buffers." If a slowing car fails to make a complete stop at the terminal, it would bump and shatter the tubes, absorbing energy that might otherwise jolt the passengers or damage the vehicle.

  4. Chemotaxis of Nonbiological Colloidal Rods

    NASA Astrophysics Data System (ADS)

    Hong, Yiying; Blackman, Nicole M. K.; Kopp, Nathaniel D.; Sen, Ayusman; Velegol, Darrell

    2007-10-01

    Chemotaxis is the movement of organisms toward or away from a chemical attractant or toxin by a biased random walk process. Here we describe the first experimental example of chemotaxis outside biological systems. Platinum-gold rods 2.0μm long exhibit directed movement toward higher hydrogen peroxide concentrations through “active diffusion.” Brownian dynamics simulations reveal that no “temporal sensing” algorithm, commonly attributed to bacteria, is necessary; rather, the observed chemotaxis can be explained by random walk physics in a gradient of the active diffusion coefficient.

  5. Reactor control rod timing system. [LMFBR

    DOEpatents

    Wu, P.T.K.

    1980-03-18

    A fluid driven jet-edge whistle timing system is described for control rods of a nuclear reactor for producing real-time detection of the timing of each control rod in its scram operation. An important parameter in reactor safety, particularly for liquid metal fast breeder reactors (LMFBR), is the time deviation between the time the control rod is released and the time the rod actually reaches the down position. The whistle has a nearly pure tone signal with center frequency (above 100 kHz) far above the frequency band in which the energy of the background noise is concentrated. Each control rod can be fitted with a whistle with a different frequency so that there is no ambiguity in differentiating the signal from each control rod.

  6. Fuel rod retention device for a nuclear reactor

    DOEpatents

    Hylton, Charles L.

    1984-01-01

    A device is described for supporting a nuclear fuel rod in a fuel rod assembly which allows the rod to be removed without disturbing other rods in the assembly. A fuel rod cap connects the rod to a bolt which is supported in the assembly end fitting by means of a locking assembly. The device is designed so that the bolt is held securely during normal reactor operation yet may be easily disengaged and the fuel rod removed when desired.

  7. Uncertainty analysis of spent nuclear fuel isotopics and rod internal pressure

    NASA Astrophysics Data System (ADS)

    Bratton, Ryan N.

    The bias and uncertainty in fuel isotopic calculations for a well-defined radio- chemical assay benchmark are investigated with Sampler, the new sampling-based uncertainty quantification tool in the SCALE code system. Isotopic predictions are compared to measurements of fuel rod MKP109 of assembly D047 from the Calvert Cliffs Unit 1 core at three axial locations, representing a range of discharged fuel burnups. A methodology is developed which quantifies the significance of input parameter uncertainties and modeling decisions on isotopic prediction by compar- ing to isotopic measurement uncertainties. The SCALE Sampler model of the D047 assembly incorporates input parameter uncertainties for key input data such as multigroup cross sections, decay constants, fission product yields, the cladding thickness, and the power history for fuel rod MKP109. The effects of each set of input parameter uncertainty on the uncertainty of isotopic predictions have been quantified. In this work, isotopic prediction biases are identified and an investiga- tion into their sources is proposed; namely, biases have been identified for certain plutonium, europium, and gadolinium isotopes for all three axial locations. More- over, isotopic prediction uncertainty resulting from only nuclear data is found to be greatest for Eu-154, Gd-154, and Gd-160. 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 as- sembly movements and assembly batch fabrication information to build individual FRAPCON inputs for each considered WBN1 fuel rod. An alternate model for the amount of helium released from zirconium diboride (ZrB2) integral fuel burn- able absorber (IFBA) layers is

  8. Solar concentrator/absorber

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G. F.

    1976-01-01

    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  9. Neutron Absorbing Alloys

    SciTech Connect

    Mizia, Ronald E.; Shaber, Eric L.; DuPont, John N.; Robino, Charles V.; Williams, David B.

    2004-05-04

    The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

  10. Shock Absorbing Helmets

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This paper presents a description of helmets used by football players that offer three times the shock-absorbing capacity of earlier types. An interior padding for the helmets, composed of Temper Foam, first used by NASA's Ames Research Center in the design of aircraft seats is described.

  11. Acoustic loading effects on oscillating rod bundles

    SciTech Connect

    Lin, W.H.

    1980-01-01

    An analytical study of the interaction between an infinite acoustic medium and a cluster of circular rods is described. The acoustic field due to oscillating rods and the acoustic loading on the rods are first solved in a closed form. The acoustic loading is then used as a forcing function for rod responses, and the acousto-elastic couplings are solved simultaneously. Numerical examples are presented for several cases to illustrate the effects of various system parameters on the acoustic reaction force coefficients. The effect of the acoustic loading on the coupled eigenfrequencies are discussed.

  12. Equations determine reasonable rod pump submergence depth

    SciTech Connect

    Hu Yongquan; Cai Wizhong

    1997-03-24

    A reasonable rod pump submergence depth can be calculated by combining fluid level changes with piston travel. Submergence depth is affected by the pump fill factor, reservoir fluid viscosity, rod pump type, and pumping parameters such as pump diameter, polished-rod stroke length, and pumping speed. Fluid level velocity can be obtained with an energy balance, and piston travel rate is based on the polished-rod travel. The paper describes the pump fill factor, piston travel velocity, fluid level rise, flow coefficient, reasonable submergence depth, and results from equations.

  13. Temperature actuated automatic safety rod release

    DOEpatents

    Hutter, Ernest; Pardini, John A.; Walker, David E.

    1987-01-01

    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.

  14. Temperature actuated automatic safety rod release

    DOEpatents

    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.

  15. Effects of rod worth and drop speed on the BWR off-center rod drop accident

    SciTech Connect

    Cokinos, D.M.; Carew, J.F.

    1985-01-01

    BWR off-center RDA calculations have been performed for selected rod worths and drop speeds. While in all cases the peak fuel enthalpy was well below the 280 cal/g fuel criterion, a substantial sensitivity to control rod worth and rod drop speed was observed.

  16. Connexin 36 and Rod Bipolar Cell Independent Rod Pathways Drive Retinal Ganglion Cells and Optokinetic Reflexes

    PubMed Central

    Cowan, Cameron S.; Abd-El-Barr, Muhammad; van der Heijden, Meike; Lo, Eric M.; Paul, David; Bramblett, Debra E.; Lem, Janis; Simons, David L.; Wu, Samuel M.

    2016-01-01

    Rod pathways are a parallel set of synaptic connections which enable night vision by relaying and processing rod photoreceptor light responses. We use dim light stimuli to isolate rod pathway contributions to downstream light responses then characterize these contributions in knockout mice lacking rod transducin-α (Trα), or certain pathway components associated with subsets of rod pathways. These comparisons reveal that rod pathway driven light sensitivity in retinal ganglion cells (RGCs) is entirely dependent on Trα, but partially independent of connexin 36 (Cx36) and rod bipolar cells. Pharmacological experiments show that rod pathway-driven and Cx36-independent RGC ON responses are also metabotropic glutamate receptor 6-dependent. To validate the RGC findings in awake, behaving animals we measured optokinetic reflexes (OKRs), which are sensitive to changes in ON pathways. Scotopic OKR contrast sensitivity was lost in Trα−/− mice, but indistinguishable from controls in Cx36−/− and rod bipolar cell knockout mice. Mesopic OKRs were also altered in mutant mice: Trα−/− mice had decreased spatial acuity, rod BC knockouts had decreased sensitivity, and Cx36−/− mice had increased sensitivity. These results provide compelling evidence against the complete Cx36 or rod BC dependence of night vision's ON component. Further, the findings suggest the parallel nature of rod pathways provides considerable redundancy to scotopic light sensitivity but distinct contributions to mesopic responses through complicated interactions with cone pathways. PMID:26718442

  17. Investigation of the Effect of Fixed Absorbers on the Reactivity of PWR Spent Nuclear Fuel for Burnup Credit

    SciTech Connect

    Wagner, John C.; Sanders, Charlotta E.

    2002-08-15

    The effect of fixed absorbers on the reactivity of pressurized water reactor (PWR) spent nuclear fuel (SNF) in support of burnup-credit criticality safety analyses is examined. A fuel assembly burned in conjunction with fixed absorbers may have a higher reactivity for a given burnup than an assembly that has not used fixed absorbers. As a result, guidance on burnup credit, issued by the U.S. Nuclear Regulatory Commission's Spent Fuel Project Office, recommends restricting the use of burnup credit to assemblies that have not used burnable absorbers. This recommendation eliminates a large portion of the currently discharged SNF from loading in burnup credit casks and thus severely limits the practical usefulness of burnup credit. Therefore, data are needed to support the extension of burnup credit to additional SNF. This research investigates the effect of various fixed absorbers, including integral burnable absorbers, burnable poison rods, control rods, and axial power shaping rods, on the reactivity of PWR SNF. Trends in reactivity with relevant parameters (e.g., initial fuel enrichment, burnup and absorber type, exposure, and design) are established, and anticipated reactivity effects are quantified. Where appropriate, recommendations are offered for addressing the reactivity effects of the fixed absorbers in burnup-credit safety analyses.

  18. Metasurface Broadband Solar Absorber

    PubMed Central

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. PMID:26828999

  19. Metasurface Broadband Solar Absorber

    DOE PAGES

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; ...

    2016-02-01

    Here, we demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Moreover, our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributionsmore » to elucidate how the absorption occurs within the metasurface structure.« less

  20. Metasurface Broadband Solar Absorber

    SciTech Connect

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    Here, we demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Moreover, our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

  1. Ionized Absorbers in AGN

    NASA Technical Reports Server (NTRS)

    Mathur, S.

    1999-01-01

    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  2. Longitudinal Impact of Rods: A Continuing Experiment.

    ERIC Educational Resources Information Center

    Britton, W. G. B.; And Others

    1978-01-01

    Describes an undergraduate experiment of research potential. The experiment cconsists of measuring the time of contact of a metal rod bouncing on a steel base as a function of the velocity of impact, length, diameter, and material of the rod. (GA)

  3. Tipping Time of a Quantum Rod

    ERIC Educational Resources Information Center

    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…

  4. An investigation of scramming the outer shutdown rods of the ANS with no reversal of flow in the manifold inlet lines

    SciTech Connect

    Morsk, K. )

    1992-10-01

    This report provides calculations and calculation checks on the outer shutdown system, consisting of eight shutdown rods located on the outside of the core. The function of the system is to scram the reactor, or to break the chain reaction of the fission process. The shutdown rods are clad with a neutron-absorbing material (i.e., hafnium) to achieve scram. During normal operation, the outer shutdown rods (Fig. 1) are in a nonscram, withdrawn position. This means that they are not close enough to the core to absorb a significant number of the neutrons that cause the fission process. In the case of a malfunction or an emergency, the outer control rods are moved to a position near the core. The outer shutdown system is operated with the use of springs and hydraulics. During normal operation, a constant flow of heavy water is circulated through the reflector vessel. A part of this flow provides a pressure high enough to keep the rods in their withdrawn or upper position, a nonscram status. If any signs of abnormal operation occur, the valves in the hydraulic system cut off the flow, and the springs push the rods into the scram position, stopping the chain reaction. Once the flow is restarted, the rods can be withdrawn to the nonscram position. Calculations of the mass of the outer control rod, the scram spring data, and the hydraulic pressure to hold the rods in the withdrawn position have been checked. In the case of a malfunction of the flow/pressure relief valves, a calculation was needed to show that the scram time would not exceed the time allowed. The scram time has been determined based on different values of the rod insertion length and the outside radius of the annulus was calculated. The effective force pushing the rod into the scram position, the rate of acceleration, and the actual scram time was then determined.

  5. Vortex Noise from Rotating Cylindrical Rods

    NASA Technical Reports Server (NTRS)

    Stowell, E Z; Deming, A F

    1935-01-01

    A series of round rods of the some diameter were rotated individually about the mid-point of each rod. Vortices are shed from the rods when in motion, giving rise to the emission of sound. With the rotating system placed in the open air, the distribution of sound in space, the acoustical power output, and the spectral distribution have been studied. The frequency of emission of vortices from any point on the rod is given by the formula von Karman. From the spectrum estimates are made of the distribution of acoustical power along the rod, the amount of air concerned in sound production, the "equivalent size" of the vortices, and the acoustical energy content for each vortex.

  6. Rod-Coil Block Polyimide Copolymers

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Kinder, James D. (Inventor)

    2005-01-01

    This invention is a series of rod-coil block polyimide copolymers that are easy to fabricate into mechanically resilient films with acceptable ionic or protonic conductivity at a variety of temperatures. The copolymers consist of short-rigid polyimide rod segments alternating with polyether coil segments. The rods and coil segments can be linear, branched or mixtures of linear and branched segments. The highly incompatible rods and coil segments phase separate, providing nanoscale channels for ion conduction. The polyimide segments provide dimensional and mechanical stability and can be functionalized in a number of ways to provide specialized functions for a given application. These rod-coil black polyimide copolymers are particularly useful in the preparation of ion conductive membranes for use in the manufacture of fuel cells and lithium based polymer batteries.

  7. Looking South at North End of Rod Loading Line Including ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking South at North End of Rod Loading Line Including Welding Area Within Rod Loading building - Hematite Fuel Fabrication Facility, Rod Loading Building, 3300 State Road P, Festus, Jefferson County, MO

  8. Absorber for terahertz radiation management

    SciTech Connect

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  9. Control rod calibration and reactivity effects at the IPEN/MB-01 reactor

    SciTech Connect

    Pinto, Letícia Negrão; Gonnelli, Eduardo; Santos, Adimir dos

    2014-11-11

    Researches that aim to improve the performance of neutron transport codes and quality of nuclear cross section databases are very important to increase the accuracy of simulations and the quality of the analysis and prediction of phenomena in the nuclear field. In this context, relevant experimental data such as reactivity worth measurements are needed. Control rods may be made of several neutron absorbing materials that are used to adjust the reactivity of the core. For the reactor operation, these experimental data are also extremely important: with them it is possible to estimate the reactivity worth by the movement of the control rod, understand the reactor response at each rod position and to operate the reactor safely. This work presents a temperature correction approach for the control rod calibration problem. It is shown the control rod calibration data of the IPEN/MB-01 reactor, the integral and differential reactivity curves and a theoretical analysis, performed by the MCNP-5 reactor physics code, developed and maintained by Los Alamos National Laboratory, using the ENDF/B-VII.0 nuclear data library.

  10. Eulerian Formulation of Spatially Constrained Elastic Rods

    NASA Astrophysics Data System (ADS)

    Huynen, Alexandre

    Slender elastic rods are ubiquitous in nature and technology. For a vast majority of applications, the rod deflection is restricted by an external constraint and a significant part of the elastic body is in contact with a stiff constraining surface. The research work presented in this doctoral dissertation formulates a computational model for the solution of elastic rods constrained inside or around frictionless tube-like surfaces. The segmentation strategy adopted to cope with this complex class of problems consists in sequencing the global problem into, comparatively simpler, elementary problems either in continuous contact with the constraint or contact-free between their extremities. Within the conventional Lagrangian formulation of elastic rods, this approach is however associated with two major drawbacks. First, the boundary conditions specifying the locations of the rod centerline at both extremities of each elementary problem lead to the establishment of isoperimetric constraints, i.e., integral constraints on the unknown length of the rod. Second, the assessment of the unilateral contact condition requires, in principle, the comparison of two curves parametrized by distinct curvilinear coordinates, viz. the rod centerline and the constraint axis. Both conspire to burden the computations associated with the method. To streamline the solution along the elementary problems and rationalize the assessment of the unilateral contact condition, the rod governing equations are reformulated within the Eulerian framework of the constraint. The methodical exploration of both types of elementary problems leads to specific formulations of the rod governing equations that stress the profound connection between the mechanics of the rod and the geometry of the constraint surface. The proposed Eulerian reformulation, which restates the rod local equilibrium in terms of the curvilinear coordinate associated with the constraint axis, describes the rod deformed configuration

  11. On-line monitoring of control rod integrity in BWRs using a mass spectrometer

    NASA Astrophysics Data System (ADS)

    Larsson, I.; Loner, H.; Ammon, K.; Sihver, L.; Ledergerber, G.

    2013-01-01

    Surveillance of fuel and control rod integrity in the core of a boiling water reactor is essential for maintaining a safe and reliable operation. Control rods of a boiling water reactor are mainly filled with boron carbide as a neutron absorber. Due to the irradiation of boron with neutrons, a continuous production of lithium and helium will occur inside a control rod. Most of the created helium will be retained in the boron carbide lattice; however a small part will escape into the void volume of the control blade. Therefore the integrity of control rods during operation can efficiently be followed by on-line measurements of helium concentration in the reactor off-gas system using a mass spectrometer. Since helium is a fill gas in fuel rods, the same method is a useful early warning system for primary fuel failures. In this paper, we introduce an on-line helium detector system which is installed at the nuclear power plant in Leibstadt. Furthermore the measuring experiences of control rod failure detection at the plant are presented. Different causes of increased helium levels in the off-gas system have been distinguished. There are spontaneous helium releases as well as helium releases caused by changed conditions in the reactor (power reduction, control rod movement, etc.). Helium peaks can also be characterized according to the released amount of helium, the peak shape and the duration of the release, which leads to different interpretations of the release mechanisms. In addition, the measured amount of released helium from a 50 days period (280 l) is also compared to the calculated amount of produced helium from the washed out boron during the same time period (190 l).

  12. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  13. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  14. Remote disassembly of the absorber open-test assembly at the FFTF/IEM cell

    SciTech Connect

    Ramsey, E.B.

    1990-01-01

    The Fast Flux Test Facility (FFTF) interim examination and maintenance (IEM) cell is used for the remote disassembly of irradiated fuel and material experiments. The absorber open-test assembly (AOTA) is a 12-m (40-ft)-long instrumented absorber (control-rod-material) test assembly. Its primary purpose is to characterize the FFTF control-rod-material reaction rate during reactor operation. Instrumentation allowed temperature and pressure measurements at various locations in several absorber pins during reactor operation. After residing several months in the reactor, the assembly was transferred to the IEM cell by the closed-loop ex-vessel machine (CLEM) for separation of the irradiated portion of the experiment from the instrument stalk. After separation, the 3.6-m (12-ft)-long assembly was processed through the sodium removal system and shipped off-site for examination. This success allowed the timely completion of a major task on the FFTF operations schedule.

  15. Evaluation of rodded BWR assembly pin powers with simulate

    SciTech Connect

    Bahadir, T.; Lindahl, S. Oe.

    2012-07-01

    In the development of Studsvik's nodal code SIMULATE5, special attention has been given to the accurate description of pin powers. The code solves the multi-group diffusion or simplified P3 equations with high spatial resolution. A short description is given of the handling of material heterogeneities in the axial and radial directions - the axial re-homogenization and the radial sub-mesh model, respectively. Furthermore, two models which are of special importance in the presence of control rods, and hence on the pellet clad interaction (PCI) phenomenon, are described; the quarter-assembly thermal-hydraulic treatment and the depletion of absorber material. A numerical example for a real core shows that while the impact of the fine grained description is negligible on global parameters such as k{sub eff}, the effect on pin powers may be substantial. For a deeply inserted and highly depleted control rod, the difference in pin powers caused by neglecting the advanced models of SIMULATE5, may be as high as 15 %. (authors)

  16. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  17. Granular materials interacting with thin flexible rods

    NASA Astrophysics Data System (ADS)

    Neto, Alfredo Gay; Campello, Eduardo M. B.

    2017-04-01

    In this work, we develop a computational model for the simulation of problems wherein granular materials interact with thin flexible rods. We treat granular materials as a collection of spherical particles following a discrete element method (DEM) approach, while flexible rods are described by a large deformation finite element (FEM) rod formulation. Grain-to-grain, grain-to-rod, and rod-to-rod contacts are fully permitted and resolved. A simple and efficient strategy is proposed for coupling the motion of the two types (discrete and continuum) of materials within an iterative time-stepping solution scheme. Implementation details are shown and discussed. Validity and applicability of the model are assessed by means of a few numerical examples. We believe that robust, efficiently coupled DEM-FEM schemes can be a useful tool to the simulation of problems wherein granular materials interact with thin flexible rods, such as (but not limited to) bombardment of grains on beam structures, flow of granular materials over surfaces covered by threads of hair in many biological processes, flow of grains through filters and strainers in various industrial segregation processes, and many others.

  18. Morphoelastic rods Part II: Growing birods

    NASA Astrophysics Data System (ADS)

    Lessinnes, Thomas; Moulton, Derek E.; Goriely, Alain

    2017-03-01

    The general problem of determining the shape and response of two attached growing elastic Kirchhoff rods is considered. A description of the kinematics of the individual interacting rods is introduced. Each rod has a given intrinsic shape and constitutive laws, and a map associating points on the two rods is defined. The resulting filamentary structure, a growing birod, can be seen as a new filamentary structure. This kinematic description is used to derive the general equilibrium equations for the shape of the rods under loads, or equivalently, for the new birod. It is shown that, in general, the birod is not simply a Kirchhoff rod but rather, due to the internal constraints, new effects can appear. The two-dimensional restriction is then considered explicitly and the limit for small deformation is shown to be equivalent to the classic Timsohenko bi-metallic strip problem. A number of examples and applications are presented. In particular, the problem of two attached rods with intrinsic helical shape and uniform growth is computed in detail and a host of new interesting solutions and bifurcations are observed.

  19. DEVICE FOR CONTROLLING INSERTION OF ROD

    DOEpatents

    Beaty, B.J.

    1958-10-14

    A device for rapidly inserting a safety rod into a nuclear reactor upon a given signal or in the event of a power failure in order to prevent the possibility of extensive damage caused by a power excursion is described. A piston is slidably mounted within a vertical cylinder with provision for an electromagnetic latch at the top of the cylinder. This assembly, with a safety rod attached to the piston, is mounted over an access port to the core region of the reactor. The piston is normally latched at the top of the cylinder with the safety rod clear of the core area, however, when the latch is released, the piston and rod drop by their own weight to insert the rod. Vents along the side of the cylinder permit the escape of the air entrapped under the piston over the greater part of the distance, however, at the end of the fall the entrapped air is compressed thereby bringing the safety rod gently to rest, thus providing for a rapid automatic insertion of the rod with a minimum of structural shock.

  20. Control Rod Malfunction at the NRAD Reactor

    SciTech Connect

    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.

  1. Control rod housing alignment and repair method

    SciTech Connect

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

    1992-04-07

    This patent describes a method for underwater welding of a control rod drive housing inserted through a stub tube to maintain requisite alignment and elevation of the top of the control rod drive housing to an overlying and corresponding aperture in a core plate as measured by an alignment device which determines the relative elevation and angularity with respect to the aperture. It comprises providing a welding cylinder dependent from the alignment device such that the elevation of the top of the welding cylinder is in a fixed relationship to the alignment device and is gas-proof; pressurizing the welding cylinder with inert welding gas sufficient to maintain the interior of the welding cylinder dry; lowering the welding cylinder through the aperture in the core plate by depending the cylinder with respect to the alignment device, the lowering including lowering through and adjusting the elevation relationship of the welding cylinder to the alignment device such that when the alignment device is in position to measure the elevation and angularity of the new control rod drive housing, the lower distal end of the welding cylinder extends below the upper periphery of the stub where welding is to occur; inserting a new control rod drive housing through the stub tube and positioning the control rod drive housing to a predetermined relationship to the anticipated final position of the control rod drive housing; providing welding implements transversely rotatably mounted interior of the welding cylinder relative to the alignment device such that the welding implements may be accurately positioned for dispensing weldment around the periphery of the top of the stub tube and at the side of the control rod drive housing; measuring the elevation and angularity of the control rod drive housing; and dispensing weldment along the top of the stub tube and at the side of the control rod drive housing.

  2. The Mechanical Effect of Rod Contouring on Rod-Screw System Strength in Spine Fixation

    PubMed Central

    Karakasli, Ahmet; Karaarslan, Ahmet A.; Ozcanhan, Mehmet Hilal; Ertem, Fatih; Erduran, Mehmet

    2016-01-01

    Objective Rod-screw fixation systems are widely used for spinal instrumentation. Although many biomechanical studies on rod-screw systems have been carried out, but the effects of rod contouring on the construct strength is still not very well defined in the literature. This work examines the mechanical impact of straight, 20° kyphotic, and 20° lordotic rod contouring on rod-screw fixation systems, by forming a corpectomy model. Methods The corpectomy groups were prepared using ultra-high molecular weight polyethylene samples. Non-destructive loads were applied during flexion/extension and torsion testing. Spine-loading conditions were simulated by load subjections of 100 N with a velocity of 5 mm min-1, to ensure 8.4-Nm moment. For torsional loading, the corpectomy models were subjected to rotational displacement of 0.5° s-1 to an end point of 5.0°, in a torsion testing machine. Results Under both flexion and extension loading conditions the stiffness values for the lordotic rod-screw system were the highest. Under torsional loading conditions, the lordotic rod-screw system exhibited the highest torsional rigidity. Conclusion We concluded that the lordotic rod-screw system was the most rigid among the systems tested and the risk of rod and screw failure is much higher in the kyphotic rod-screw systems. Further biomechanical studies should be attempted to compare between different rod kyphotic angles to minimize the kyphotic rod failure rate and to offer a more stable and rigid rod-screw construct models for surgical application in the kyphotic vertebrae. PMID:27651858

  3. Taylor impact of glass rods

    SciTech Connect

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

    2005-05-01

    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 {approx}2 GPa the failure front velocity increases rapidly with increasing pressure. As the pressure was increased above {approx}3 GPa, the failure front velocities asymptotically approached maximum values between the longitudinal and shear wave velocities of each material; at {approx}4 GPa, the average failure front velocities were 4.7{+-}0.5 and 4.6{+-}0.5 mm {mu}s{sup -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. Control rod drive hydraulic system

    DOEpatents

    Ose, Richard A.

    1992-01-01

    A hydraulic system for a control rod drive (CRD) includes a variable output-pressure CR pump operable in a charging mode for providing pressurized fluid at a charging pressure, and in a normal mode for providing the pressurized fluid at a purge pressure, less than the charging pressure. Charging and purge lines are disposed in parallel flow between the CRD pump and the CRD. A hydraulic control unit is disposed in flow communication in the charging line and includes a scram accumulator. An isolation valve is provided in the charging line between the CRD pump and the scram accumulator. A controller is operatively connected to the CRD pump and the isolation valve and is effective for opening the isolation valve and operating the CRD pump in a charging mode for charging the scram accumulator, and closing the isolation valve and operating the CRD pump in a normal mode for providing to the CRD through the purge line the pressurized fluid at a purge pressure lower than the charging pressure.

  5. Liquid Cryogen Absorber for MICE

    SciTech Connect

    Baynham, D.E.; Bish, P.; Bradshaw, T.W.; Cummings, M.A.; Green,M.A.; Ishimoto, S.; Ivaniouchenkov, I.; Lau, W.; Yang, S.Q.; Zisman, M.S.

    2005-08-20

    The Muon Ionization Cooling Experiment (MICE) will test ionization cooling of muons. In order to have effective ionization cooling, one must use an absorber that is made from a low-z material. The most effective low z materials for ionization cooling are hydrogen, helium, lithium hydride, lithium and beryllium, in that order. In order to measure the effect of material on cooling, several absorber materials must be used. This report describes a liquid-hydrogen absorber that is within a pair of superconducting focusing solenoids. The absorber must also be suitable for use with liquid helium. The following absorber components are discussed in this report; the absorber body, its heat exchanger, the hydrogen system, and the hydrogen safety. Absorber cooling and the thin windows are not discussed here.

  6. The CASMO-4 r-z pin cell calculation for lattices containing gray gadolinia rods

    SciTech Connect

    Knott, D.; Edenius, M. )

    1992-01-01

    In lattice physics codes, pin cell calculations are performed to produce a flux spectrum that is then used to condense and, if desired, homogenize the cross sections of each pin cell to a smaller group structure in preparation for the two-dimensional transport calculation on the entire lattice. If the pellets within a fuel pin are uniform within an axial region of the assembly represented by the lattice, the pin cell calculation may be performed using a one-dimensional cylindrical geometry. This geometry applies to most pin types, including fuel pins containing burnable absorbers, such as gadolinia. These gadolinia pin types, where the pellets are uniform axially, are called black gadolinia rods. In certain ABB designs, gadolinia pellets and UO{sub 2} pellets are alternately stacked within some portion of a fuel rod. Such rods, called gray gadolinia rods, enhance the depletion rate of the gadolinia. For these designs, the fuel rods are no longer uniform in the axial direction, and a one-dimensional cylindrical pin cell calculation is no longer applicable. To this end, CASMO-4 includes the capability to perform the pin cell calculation using a two-dimensional r-z geometry. The r-z pin cell calculation in CASMO-4 allows one more degree of freedom when considering burnable absorber design for reactivity control. The use of the collision probability flux solution lends consistency to the overall model, and the variable mesh capability allows the user to place detail where it is most needed. The r-z geometry may also find other applications in the future.

  7. Laser-assisted growth of molybdenum rods

    NASA Astrophysics Data System (ADS)

    Björklund, K. L.; Heszler, P.; Boman, M.

    2002-01-01

    In this paper, we report for the first time the laser-assisted growth of molybdenum rods via the H 2 reduction of MoF 6 with a focused Ar + laser beam as the heat source. By varying the gas composition, total pressure, and laser power rods with different morphologies were deposited on a tungsten wire. At low H 2/MoF 6 molar ratios crystal-like rods were obtained and at higher molar ratios the rods became dendrite-like. The activation energy for the process was determined to be 77±7 kJ mol -1 in the temperature range 705-840 K. The reaction order showed to be nearly 3 with respect to the hydrogen partial pressure and zero order with respect to the molybdenum hexafluoride partial pressure. Compositional and morphological characterisation were performed with scanning electron microscopy, energy dispersed X-ray spectroscopy and Auger electron spectroscopy.

  8. Control rod for a nuclear reactor

    DOEpatents

    Roman, Walter G.; Sutton, Jr., Harry G.

    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.

  9. Ferroelectrics based absorbing layers

    NASA Astrophysics Data System (ADS)

    Hao, Jianping; Sadaune, Véronique; Burgnies, Ludovic; Lippens, Didier

    2014-07-01

    We show that ferroelectrics-based periodic structure made of BaSrTiO3 (BST) cubes, arrayed onto a metal plate with a thin dielectric spacer film exhibit a dramatic enhancement of absorbance with value close to unity. The enhancement is found around the Mie magnetic resonance of the Ferroelectrics cubes with the backside metal layer stopping any transmitted waves. It also involves quasi-perfect impedance matching resulting in reflection suppression via simultaneous magnetic and electrical activities. In addition, it was shown numerically the existence of a periodicity optimum, which is explained from surface waves analysis along with trade-off between the resonance damping and the intrinsic loss of ferroelectrics cubes. An experimental verification in a hollow waveguide configuration with a good comparison with full-wave numerical modelling is at last reported by measuring the scattering parameters of single and dual BST cubes schemes pointing out coupling effects for densely packed structures.

  10. Dual broadband metamaterial absorber.

    PubMed

    Kim, Young Ju; Yoo, Young Joon; Kim, Ki Won; Rhee, Joo Yull; Kim, Yong Hwan; Lee, YoungPak

    2015-02-23

    We propose polarization-independent and dual-broadband metamaterial absorbers at microwave frequencies. This is a periodic meta-atom array consisting of metal-dielectric-multilayer truncated cones. We demonstrate not only one broadband absorption from the fundamental magnetic resonances but additional broadband absorption in high-frequency range using the third-harmonic resonance, by both simulation and experiment. In simulation, the absorption was over 90% in 3.93-6.05 GHz, and 11.64-14.55 GHz. The corresponding experimental absorption bands over 90% were 3.88-6.08 GHz, 9.95-10.46 GHz and 11.86-13.84 GHz, respectively. The origin of absorption bands was elucidated. Furthermore, it is independent of polarization angle owing to the multilayered circular structures. The design is scalable to smaller size for the infrared and the visible ranges.

  11. THz-metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Tuong Pham, Van; Park, J. W.; Vu, Dinh Lam; Zheng, H. Y.; Rhee, J. Y.; Kim, K. W.; Lee, Y. P.

    2013-03-01

    An ultrabroad-band metamaterial absorber was investigated in mid-IR regime based on a similar model in previous work. The high absorption of metamaterial was obtained in a band of 8-11.7 THz with energy loss distributed in SiO2, which is appropriate potentially for solar-cell applications. A perfect absorption peak was provided by using a sandwich structure with periodical anti-dot pattern in the IR region, getting closed to visible-band metamaterials. The dimensional parameters were examined for the corresponding fabrication. Invited talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology, 30 October-2 November, 2012, Ha Long, Vietnam.

  12. Double-clad nuclear fuel safety rod

    DOEpatents

    McCarthy, William H.; Atcheson, Donald B.; Vaidyanathan, Swaminathan

    1984-01-01

    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.

  13. Microelectrophoresis of Silica Rods Using Confocal Microscopy

    PubMed Central

    2017-01-01

    The electrophoretic mobility and the zeta potential (ζ) of fluorescently labeled colloidal silica rods, with an aspect ratio of 3.8 and 6.1, were determined with microelectrophoresis measurements using confocal microscopy. In the case where the colloidal particles all move at the same speed parallel to the direction of the electric field, we record a xyz-stack over the whole depth of the capillary. This method is faster and more robust compared to taking xyt-series at different depths inside the capillary to obtain the parabolic flow profile, as was done in previous work from our group. In some cases, rodlike particles do not move all at the same speed in the electric field, but exhibit a velocity that depends on the angle between the long axis of the rod and the electric field. We measured the orientation-dependent velocity of individual silica rods during electrophoresis as a function of κa, where κ–1 is the double layer thickness and a is the radius of the rod associated with the diameter. Thus, we determined the anisotropic electrophoretic mobility of the silica rods with different sized double layers. The size of the double layer was tuned by suspending silica rods in different solvents at different electrolyte concentrations. We compared these results with theoretical predictions. We show that even at already relatively high κa when the Smoluchowski limiting law is assumed to be valid (κa > 10), an orientation dependent velocity was measured. Furthermore, we observed that at decreasing values of κa the anisotropy in the electrophoretic mobility of the rods increases. However, in low polar solvents with κa < 1, this trend was reversed: the anisotropy in the electrophoretic mobility of the rods decreased. We argue that this decrease is due to end effects, which was already predicted theoretically. When end effects are not taken into account, this will lead to strong underestimation of the experimentally determined zeta potential. PMID:28045541

  14. Calculator program speeds rod pump design

    SciTech Connect

    Engineer, R.; Davis, C.L.

    1984-02-01

    Matching sucker rod pump characteristics to a specific application is greatly simplified with this program, intended for use with an HP-41CV hand-held computer. The user inputs application data and the program calculates all necessary design criteria, including Mill's acceleration factor, peak and minimum polish rod loads and horsepower required. Sample calculations are provided, together with a thorough discussion of special design considerations involved in huff-and-puff applications.

  15. Epigenomic landscapes of retinal rods and cones

    PubMed Central

    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

  16. Rigid rod anchored to infinite membrane.

    PubMed

    Guo, Kunkun; Qiu, Feng; Zhang, Hongdong; Yang, Yuliang

    2005-08-15

    We investigate the shape deformation of an infinite membrane anchored by a rigid rod. The density profile of the rod is calculated by the self-consistent-field theory and the shape of the membrane is predicted by the Helfrich membrane elasticity theory [W. Helfrich, Z. Naturforsch. 28c, 693 (1973)]. It is found that the membrane bends away from the rigid rod when the interaction between the rod and the membrane is repulsive or weakly attractive (adsorption). However, the pulled height of the membrane at first increases and then decreases with the increase of the adsorption strength. Compared to a Gaussian chain with the same length, the rigid rod covers much larger area of the membrane, whereas exerts less local entropic pressure on the membrane. An evident gap is found between the membrane and the rigid rod because the membrane's curvature has to be continuous. These behaviors are compared with that of the flexible-polymer-anchored membranes studied by previous Monte Carlo simulations and theoretical analysis. It is straightforward to extend this method to more complicated and real biological systems, such as infinite membrane/multiple chains, protein inclusion, or systems with phase separation.

  17. Close packing of rods on spherical surfaces

    NASA Astrophysics Data System (ADS)

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-01

    We study the optimal packing of short, hard spherocylinders confined to lie tangential to a spherical surface, using simulated annealing and molecular dynamics simulations. For clusters of up to twelve particles, we map out the changes in the geometry of the closest-packed configuration as a function of the aspect ratio L/D, where L is the cylinder length and D the diameter of the rods. We find a rich variety of cluster structures. For larger clusters, we find that the best-packed configurations up to around 100 particles are highly dependent on the exact number of particles and aspect ratio. For even larger clusters, we find largely disordered clusters for very short rods (L/D = 0.25), while slightly longer rods (L/D = 0.5 or 1) prefer a global baseball-like geometry of smectic-like domains, similar to the behavior of large-scale nematic shells. Intriguingly, we observe that when compared to their optimal flat-plane packing, short rods adapt to the spherical geometry more efficiently than both spheres and longer rods. Our results provide predictions for experimentally realizable systems of colloidal rods trapped at the interface of emulsion droplets.

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

    SciTech Connect

    McCulloch, R.W.

    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.

  19. Electrochemically regenerable carbon dioxide absorber

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

    1979-01-01

    Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

  20. Broadband patterned magnetic microwave absorber

    SciTech Connect

    Li, Wei; Wu, Tianlong; Wang, Wei; Guan, Jianguo; Zhai, Pengcheng

    2014-07-28

    It is a tough task to greatly improve the working bandwidth for the traditional flat microwave absorbers because of the restriction of available material parameters. In this work, a simple patterning method is proposed to drastically broaden the absorption bandwidth of a conventional magnetic absorber. As a demonstration, an ultra-broadband microwave absorber with more than 90% absorption in the frequency range of 4–40 GHz is designed and experimentally realized, which has a thin thickness of 3.7 mm and a light weight equivalent to a 2-mm-thick flat absorber. In such a patterned absorber, the broadband strong absorption is mainly originated from the simultaneous incorporation of multiple λ/4 resonances and edge diffraction effects. This work provides a facile route to greatly extend the microwave absorption bandwidth for the currently available absorbing materials.

  1. Liquid Hydrogen Absorber for MICE

    SciTech Connect

    Ishimoto, S.; Suzuki, S.; Yoshida, M.; Green, Michael A.; Kuno, Y.; Lau, Wing

    2010-05-30

    Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with {approx}2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.

  2. Nuclear reactor remote disconnect control rod coupling indicator

    DOEpatents

    Vuckovich, Michael

    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. 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.

  3. A New Insight into Energy Distribution of Electrons in Fuel-Rod Gap in VVER-1000 Nuclear Reactor

    NASA Astrophysics Data System (ADS)

    Fereshteh, Golian; Ali, Pazirandeh; Saeed, Mohammadi

    2015-06-01

    In order to calculate the electron energy distribution in the fuel rod gap of a VVER-1000 nuclear reactor, the Fokker-Planck equation (FPE) governing the non-equilibrium behavior of electrons passing through the fuel-rod gap as an absorber has been solved in this paper. Besides, the Monte Carlo Geant4 code was employed to simulate the electron migration in the fuel-rod gap and the energy distribution of electrons was found. As for the results, the accuracy of the FPE was compared to the Geant4 code outcomes and a satisfactory agreement was found. Also, different percentage of the volatile and noble gas fission fragments produced in fission reactions in fuel rod, i.e. Krypton, Xenon, Iodine, Bromine, Rubidium and Cesium were employed so as to investigate their effects on the electrons' energy distribution. The present results show that most of the electrons in the fuel rod's gap were within the thermal energy limitation and the tail of the electron energy distribution was far from a Maxwellian distribution. The interesting outcome was that the electron energy distribution is slightly increased due to the accumulation of fission fragments in the gap. It should be noted that solving the FPE for the energy straggling electrons that are penetrating into the fuel-rod gap in the VVER-1000 nuclear reactor has been carried out for the first time using an analytical approach.

  4. Recent High Heat Flux Tests on W-Rod-Armored Mockups

    SciTech Connect

    NYGREN,RICHARD E.; YOUCHISON,DENNIS L.; MCDONALD,JIMMIE M.; LUTZ,THOMAS J.; MISZKIEL,MARK E.

    2000-07-18

    In the authors initial high heat flux tests on small mockups armored with W rods, done in the small electron beam facility (EBTS) at Sandia National Laboratories, the mockups exhibited excellent thermal performance. However, to reach high heat fluxes, they reduced the heated area to only a portion ({approximately}25%) of the sample. They have now begun tests in their larger electron beam facility, EB 1200, where the available power (1.2 MW) is more than enough to heat the entire surface area of the small mockups. The initial results indicate that, at a given power, the surface temperatures of rods in the EB 1200 tests is somewhat higher than was observed in the EBTS tests. Also, it appears that one mockup (PW-10) has higher surface temperatures than other mockups with similar height (10mm) W rods, and that the previously reported values of absorbed heat flux on this mockup were too high. In the tests in EB 1200 of a second mockup, PW-4, absorbed heat fluxes of {approximately}22MW/m{sup 2} were reached but the corresponding surface temperatures were somewhat higher than in EBTS. A further conclusion is that the simple 1-D model initially used in evaluating some of the results from the EBTS testing was not adequate, and 3-D thermal modeling will be needed to interpret the results.

  5. Regulatory perspective on incomplete control rod insertions

    SciTech Connect

    Chatterton, M.

    1997-01-01

    The incomplete control rod insertions experienced at South Texas Unit 1 and Wolf Creek are of safety concern to the NRC staff because they represent potential precursors to loss of shutdown margin. Even before it was determined if these events were caused by the control rods or by the fuel there was an apparent correlation of the problem with high burnup fuel. It was determined that there was also a correlation between high burnup and high drag forces as well as with rod drop time histories and lack of rod recoil. The NRC staff initial actions were aimed at getting a perspective on the magnitude of the problem as far as the number of plants and the amount of fuel that could be involved, as well as the safety significance in terms of shutdown margin. As tests have been performed and data has been analyzed the focus has shifted more toward understanding the problem and the ways to eliminate it. At this time the staff`s understanding of the phenomena is that it was a combination of factors including burnup, power history and temperature. The problem appears to be very sensitive to these factors, the interaction of which is not clearly understood. The model developed by Westinghouse provides a possible explanation but there is not sufficient data to establish confidence levels and sensitivity studies involving the key parameters have not been done. While several fixes to the problem have been discussed, no definitive fixes have been proposed. Without complete understanding of the phenomena, or fixes that clearly eliminate the problem the safety concern remains. The safety significance depends on the amount of shutdown margin lost due to incomplete insertion of the control rods. Were the control rods to stick high in the core, the reactor could not be shutdown by the control rods and other means such as emergency boration would be required.

  6. Effects of Burnable Absorbers on PWR Spent Nuclear Fuel

    SciTech Connect

    P.M. O'Leary; Dr. M.L. Pitts

    2000-08-21

    Burnup credit is an ongoing issue in designing and licensing transportation and storage casks for spent nuclear fuel (SNF). To address this issue, in July 1999, the U.S. Nuclear Regulatory Commission (NRC), Spent Fuel Project Office, issued Interim Staff Guidance-8 (ISG-8), Revision 1 allowing limited burnup credit for pressurized water reactor (PWR) spent nuclear fuel (SNF) to be used in transport and storage casks. However, one of the key limitations for a licensing basis analysis as stipulated in ISG-8, Revision 1 is that ''burnup credit is restricted to intact fuel assemblies that have not used burnable absorbers''. Because many PWR fuel designs have incorporated burnable-absorber rods for more than twenty years, this restriction places an unnecessary burden on the commercial nuclear power industry. This paper summarizes the effects of in-reactor irradiation on the isotopic inventory of PWR fuels containing different types of integral burnable absorbers (BAs). The work presented is illustrative and intended to represent typical magnitudes of the reactivity effects from depleting PWR fuel with different types of burnable absorbers.

  7. Effects of rod worth and drop speed on the BWR off-center rod drop accident

    SciTech Connect

    Cokinos, D.M.; Carew, J.F.

    1986-01-01

    The purpose of the present study was to determine the effect of increasing the control rod worth and the rod drop speed on the off-center RDA. An increase in either of these parameters results in an increase in peak core power and fuel enthalpy, and the objective of this study is to determine the margin to the fuel damage threshold.

  8. Dissipative particle dynamics simulations on self-assembly of rod-coil-rod triblock copolymers in a rod-selective solvent

    NASA Astrophysics Data System (ADS)

    Huang, Jian-Hua; Fan, Zhong-Xiang; Ma, Ze-Xin

    2013-08-01

    Self-assembly of rod-coil-rod ABA triblock copolymers in a rod-selective solvent is investigated by using dissipative particle dynamics simulations. The morphologies of the self-assembled aggregates are dependent on the number of copolymers in the aggregate and the rod length of the copolymer. We observe vesicles at short rod block and bowl-like aggregates at slightly longer rod block. In the vesicle region near the phase boundary, metastable bowl-like aggregates can be observed and be transformed into vesicles by annealing process. A transition from the bowl-like structure to the vesicle is observed by increasing the solvophobicity of the mid-coil block. In this study, the difference between the self-assembly of fully flexible ABA triblock copolymer and that of rod-coil-rod triblock copolymer is also discussed.

  9. Particle-rod hybrids: growth of arachidic acid molecular rods from capped cadmium selenide nanoparticles.

    PubMed

    Chen, Dongzhong; Wang, Ruomiao; Arachchige, Indika; Mao, Guangzhao; Brock, Stephanie L

    2004-12-22

    This communication describes a spin-coating method to nucleate organic molecular rods of uniform size from an inorganic nanoparticle at a solid surface. The particle-rod hybrid structure spontaneously forms when a film is spin coated from a mixed 2-propanol solution of arachidic acid (AA) and nanoparticles of cadmium selenide capped by mercaptoundecanoic acid (MUA-CdSe) on graphite. AFM images show that MUA-CdSe nanoparticles nucleate single crystalline rods of AA with a cross section of a single unit cell of the C-form. The solution-based process potentially allows the precise tuning of the wetting profile of the solution on the surface-attached nanoparticle, which provides the reservoir for the growth of the single crystalline rods. The results suggest that nanoparticles can be regarded as nanoseeds for the nucleation of guest crystals. It should be possible to further functionalize the AA rods by electrostatic complexation with metal or organic ions.

  10. Passive electrical properties of rod outer segments

    PubMed Central

    Falk, Gertrude; Fatt, P.

    1968-01-01

    1. Measurements on a packed suspension of randomly oriented, dark-adapted frog rods at frequencies of 15 c/s-0·5 Mc/s indicate a behaviour similar to that of other biological materials. 2. Results are analysed on the assumption that the low-frequency limiting resistance is determined by current flowing in the suspending medium and that, of the rods, two thirds are oriented perpendicular to the applied field and one third parallel to it. Those parallel to the field are treated as non-conductors. 3. From the high-frequency limiting resistance the conductivity of the rod interior is calculated to vary linearly with the conductivity of the medium. The slope of the relation of internal to external conductivity is 0·50 with a limiting internal conductivity (at zero external) of 280 μmho/cm. 4. On the assumption that the suspension can be represented as a single-capacitance network, the characteristic frequency of impedance is used to calculate a capacitance for the rod surface of 1·54 μF/cm2. On the assumption of a distribution in properties of the suspension according to the theory of Bruggeman, the capacitance is calculated to have a value of about one half this. 5. At frequencies below 5 kc/s the impedance locus deviates from the curve describing the behaviour at higher frequencies. It is suggested that this may involve conduction in a thin layer extending along the surface of the rod. PMID:5685292

  11. Radiological characterization of spent control rod assemblies

    SciTech Connect

    Lepel, E.A.; Robertson, D.E.; Thomas, C.W.; Pratt, S.L.; Haggard, D.L.

    1995-10-01

    This document represents the final report of an ongoing study to provide radiological characterizations, classifications, and assessments in support of the decommissioning of nuclear power stations. This report describes the results of non-destructive and laboratory radionuclide measurements, as well as waste classification assessments, of BWR and PWR spent control rod assemblies. The radionuclide inventories of these spent control rods were determined by three separate methodologies, including (1) direct assay techniques, (2) calculational techniques, and (3) by sampling and laboratory radiochemical analyses. For the BWR control rod blade (CRB) and PWR burnable poison rod assembly (BPRA), {sup 60}Co and {sup 63}Ni, present in the stainless steel cladding, were the most abundant neutron activation products. The most abundant radionuclide in the PWR rod cluster control assembly (RCCA) was {sup 108m}Ag (130 yr halflife) produced in the Ag-In-Cd alloy used as the neutron poison. This radionuclide will be the dominant contributor to the gamma dose rate for many hundreds of years. The results of the direct assay methods agree very well ({+-}10%) with the sampling/radiochemical measurements. The results of the calculational methods agreed fairly well with the empirical measurements for the BPRA, but often varied by a factor of 5 to 10 for the CRB and the RCCA assemblies. If concentration averaging and encapsulation, as allowed by 10CFR61.55, is performed, then each of the entire control assemblies would be classified as Class C low-level radioactive waste.

  12. Wetting of a partially immersed compliant rod

    NASA Astrophysics Data System (ADS)

    Hui, Chung-Yuen; Jagota, Anand

    2016-11-01

    The force on a solid rod partially immersed in a liquid is commonly used to determine the liquid-vapor surface tension by equating the measured force required to remove the rod from the liquid to the vertical component of the liquid-vapor surface tension. Here, we study how this process is affected when the rod is compliant. For equilibrium, we enforce force and configurational energy balance, including contributions from elastic energy. We show that, in general, the contact angle does not equal that given by Young's equation. If surface stresses are tensile, the strain in the immersed part of the rod is found to be compressive and to depend only on the solid-liquid surface stress. The strain in the dry part of the rod can be either tensile or compressive, depending on a combination of parameters that we identify. We also provide results for compliant plates partially immersed in a liquid under plane strain and plane stress. Our results can be used to extract solid surface stresses from such experiments.

  13. Coiling of elastic rods on rigid substrates

    PubMed Central

    Jawed, Mohammad K.; Da, Fang; Joo, Jungseock; Grinspun, Eitan; Reis, Pedro M.

    2014-01-01

    We investigate the deployment of a thin elastic rod onto a rigid substrate and study the resulting coiling patterns. In our approach, we combine precision model experiments, scaling analyses, and computer simulations toward developing predictive understanding of the coiling process. Both cases of deposition onto static and moving substrates are considered. We construct phase diagrams for the possible coiling patterns and characterize them as a function of the geometric and material properties of the rod, as well as the height and relative speeds of deployment. The modes selected and their characteristic length scales are found to arise from a complex interplay between gravitational, bending, and twisting energies of the rod, coupled to the geometric nonlinearities intrinsic to the large deformations. We give particular emphasis to the first sinusoidal mode of instability, which we find to be consistent with a Hopf bifurcation, and analyze the meandering wavelength and amplitude. Throughout, we systematically vary natural curvature of the rod as a control parameter, which has a qualitative and quantitative effect on the pattern formation, above a critical value that we determine. The universality conferred by the prominent role of geometry in the deformation modes of the rod suggests using the gained understanding as design guidelines, in the original applications that motivated the study. PMID:25267649

  14. Energy absorber for the CETA

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1994-01-01

    The energy absorber that was developed for the CETA (Crew Equipment and Translation Aid) on Space Station Freedom is a metal on metal frictional type and has a load regulating feature that prevents excessive stroking loads from occurring while in operation. This paper highlights some of the design and operating aspects and the testing of this energy absorber.

  15. Improvement Of The Helmholtz Absorber

    NASA Technical Reports Server (NTRS)

    Morrow, Duane L.

    1992-01-01

    Helmholtz-resonator system improved to enable it to absorb sound at more than one frequency without appreciable loss of effectiveness at primary frequency. Addition of annular cavities enables absorption of sound at harmonic frequencies in addition to primary frequency. Improved absorber designed for use on structures of high transmission loss. Applied to such machines as fixed-speed engines and fans.

  16. Metal-shearing energy absorber

    NASA Technical Reports Server (NTRS)

    Fay, R. J.; Wittrock, E. P.

    1971-01-01

    Device, consisting of tongue of thin aluminum alloy strip, pull tab, slotted steel plate which serves as cutter, and steel buckle, absorbs mechanical energy when its ends are subjected to tensile loading. Device is applicable as auxiliary shock absorbing anchor for automobile and airplane safety belts.

  17. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  18. Torque requirement of rotating rods in airflow

    NASA Technical Reports Server (NTRS)

    Barna, P. S.; Crossman, G. R.

    1979-01-01

    Experiments were performed to determine the torque required for rotating a rotor disk fitted with a number of radially arranged rods placed into a ducted airflow. An array of stationary rods, also radially arranged, was placed upstream close to the rotor with a small gap between the rods to cause wake interference. The results show that torque generally increased with airflow and the rate of increase varied considerably. At lower values of airflow, the rate of increase was larger than at higher airflow, and definite torque peaks occurred at certain airflow rates, where the torque attained a maximum within the test airflow range. During the test, a maximum blade passage frequency of 2037 Hz was attained. The results also show that the torque peaks occurred at the same Strouhal number for all speeds.

  19. Processing depleted uranium quad alloy penetrator rods

    SciTech Connect

    Bokan, S.L.

    1987-02-19

    Two depleted uranium (DU) quad alloys were cast, extruded and rolled to produce penetrator rods. The two alloy combinations were (1) 1 wt % molybdenum (Mo), 1 wt % niobium (Nb), and 0.75 wt % titanium (Ti); and (2) 1 wt % tantalum (Ta), 1 wt % Nb, and 0.75 wt % Ti. This report covers the processing and results with limited metallographic information available. The two alloys were each vacuum induction melted (VIM) into an 8-in. log, extruded into a 3-in. log, then cut into 4 logs and extruded at 4 different temperatures into 0.8-in. bars. From the 8 conditions (2 alloys, 4 extrusion temperatures each), 10 to 13 16-in. rods were cut for rolling and swaging. Due to cracking problems, the final processing changed from rolling and swaging to limited rolling and heat treating. The contracted work was completed with the delivery of 88 rods to Dr. Zabielski. 28 figs.

  20. Magnetic switch for reactor control rod. [LMFBR

    DOEpatents

    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.

  1. Magnetic switch for reactor control rod

    DOEpatents

    Germer, John H.

    1986-01-01

    A magnetic reed switch assembly 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 electromagnetic grapple which allows the control rod to drop into the reactor core for controlling the reactivity of the core.

  2. Self-Contact for Rods on Cylinders

    NASA Astrophysics Data System (ADS)

    van der Heijden, G. H. M.; Peletier, M. A.; Planqué, R.

    2006-11-01

    We study self-contact phenomena in elastic rods that are constrained to lie on a cylinder. By choosing a particular set of variables to describe the rod centerline the variational setting is made particularly simple: the strain energy is a second-order functional of a single scalar variable, and the self-contact constraint is written as an integral inequality. Using techniques from ordinary differential equation theory (comparison principles) and variational calculus (cut-and-paste arguments) we fully characterize the structure of constrained minimizers. An important auxiliary result states that the set of self-contact points is continuous, a result that contrasts with known examples from contact problems in free rods.

  3. Concentration-dependent sedimentation of colloidal rods

    NASA Astrophysics Data System (ADS)

    Dogic, Z.; Philipse, A. P.; Fraden, S.; Dhont, J. K. G.

    2000-11-01

    In this paper we first develop an approximate theory for the leading order concentration dependence of the sedimentation coefficient for rodlike colloids/polymers/macromolecules. To first order in volume fraction φ of rods, the sedimentation coefficient is written as 1+αφ. For large aspect ratios L/D (L is the rod length, D its thickness) α is found to vary like ∝(L/D)2/ln(L/D). This theoretical prediction is compared to experimental results. Then, experiments on fd virus are described, both in the isotropic and nematic phase. First-order in concentration results for this very long and thin (semiflexible) rod are in agreement with the above-mentioned theoretical prediction. Sedimentation profiles for the nematic phase show two sedimentation fronts. This result indicates that the nematic phase becomes unstable with the respect to isotropic phase during sedimentation.

  4. Rod consolidation at the West Valley Demonstration Project

    SciTech Connect

    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.

  5. Control rod drive for reactor shutdown

    DOEpatents

    McKeehan, Ernest R.; Shawver, Bruce M.; Schiro, Donald J.; Taft, William E.

    1976-01-20

    A means for rapidly shutting down or scramming a nuclear reactor, such as a liquid metal-cooled fast breeder reactor, and serves as a backup to the primary shutdown system. The control rod drive consists basically of an in-core assembly, a drive shaft and seal assembly, and a control drive mechanism. The control rod is driven into the core region of the reactor by gravity and hydraulic pressure forces supplied by the reactor coolant, thus assuring that common mode failures will not interfere with or prohibit scramming the reactor when necessary.

  6. Chemical Dosimeter Tube With Coaxial Sensing Rod

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E.

    1993-01-01

    Improved length-of-stain (LOS) chemical dosimeter indicates total dose of chemical vapor in air. Made with rods and tubes of various diameters to obtain various sensitivities and dynamic ranges. Sensitivity larger and dose range smaller when more room for diffusion in gap between tube and rod. Offers greater resistance to changing of color of exposed dye back to color of unexposed condition, greater sensitivity, and higher degree of repeatability. Developed to measure doses of gaseous HCI, dosimeter modified by use of other dyes to indicate doses of other chemical vapors.

  7. Nuclear reactor fuel rod attachment system

    DOEpatents

    Not Available

    1980-09-17

    A reusable system is described 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. The locking cap has two opposing fingers 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.

  8. Optical contact approach to laser rod support.

    NASA Technical Reports Server (NTRS)

    Gurski, T. R.

    1972-01-01

    The successful application of an optical contact is described between a ruby laser rod that has no mechanical support and a sapphire rod. The contact is found to be durable in the environmental conditions associated with a high-power pulsed ruby laser. The described contact technique makes it possible to construct a laser oscillator using an ellipsoidal pump mirror that does not employ dielectric coatings in the cavity. Another advantage consists in that the ruby laser is not shaded from the pump light by mounting jigs at its ends.

  9. Method for producing titanium aluminide weld rod

    DOEpatents

    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.

  10. Improving fuel-rod performance. [PWR; BWR

    SciTech Connect

    Ocken, H.; Knott, S.

    1981-03-01

    To reduce the risk of fuel-rod failures, utilities operate their nuclear reactors within conservative limits on power increases proposed by nuclear-fuel vendors. Of particular concern to US utilities is that adopting these limits results in an industrywide average plant capacity loss of 3% in BWR designs and 0.3% in PWR designs. To replace lost BWR capacity by other generating means currently costs the utilities $150 million annually, and losses for PWRs are about $20 million. Efforts are therefore being made to identify the factors responsible for Zircaloy degradation under PCI condition and to improve nuclear-fuel-rod design and reactor operation.

  11. Rod Photoreceptor Temporal Properties in Retinitis Pigmentosa

    PubMed Central

    Wen, Yuquan; Locke, Kirsten G.; Hood, Donald C.; Birch, David G.

    2011-01-01

    One of the characteristic signs of retinitis pigmentosa (RP) is the progressive loss of night vision. We have previously shown that the gain of rod photoreceptor activation is moderately reduced in some patients with RP, but this decrease in activation kinetics is not sufficient to account for the night blindness. Recently, single rod recording from animal models of RP showed rods under degeneration remain saturated for shorter periods than normal rods; i.e. are less able to sustain the rod photoresponse. Using paired-flash ERG, here we determine whether rod phototransduction inactivation parameters might also be abnormal in patients with RP. Inactivation parameters were derived from 13 subjects with normal vision, 16 patients with adRP, and 16 patients with autosomal recessive/isolate (rec/iso) RP. The adRP cases included 9 patients with rhodopsin mutations and 7 patients with peripherin/RDS mutations. The inactivation phase was derived using a double-flash paradigm, with a test flash of 2.7 log scot td-sec followed at varying intervals by a 4.2 log scot td-sec probe flash. Derived rod photoresponses to this just-saturating test flash in normal subjects exhibit a critical time to the initiation of recovery (Tsat) of 525±90 (SD) msec. The values of Tsat were 336±104 (SD) msec in patients with adRP (P<0.001) and 271±45 (SD) msec (P<0.001) in patients with rec/iso RP. When Tsat values were categorized by mutations, the values were 294±91 (SD) msec (P<0.001) for rhodopsin mutations, and 389±100 (SD) msec (p=0.01) for peripherin/RDS mutations. Overall, Tsat in patients with RP was significantly correlated with the amplitude of ISCEV standard rod response (r = 0.56; P < 0.001) and the gain of the activation phase of phototransduction (r=0.6, P<0.001). Tsat may be a useful marker for therapeutic efficacy in future clinical trials in RP. PMID:21219898

  12. HIGH STRENGTH CONTROL RODS FOR NEUTRONIC REACTORS

    DOEpatents

    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.

  13. Intraoperative pulmonary embolism of Harrington rod during spinal surgery: the potential dangers of rod cutting.

    PubMed

    Aylott, Caspar E W; Hassan, Kamran; McNally, Donal; Webb, John K

    2006-12-01

    This is a case report and laboratory-based biomechanics study. The objective is to report the first case of Titanium rod embolisation during scoliosis surgery into the Pulmonary artery. To investigate the potential of an unconstrained cut Titanium rod fragment to cause wounding with reference to recognised weapons. Embolisation of a foreign body to the heart is rare. Bullet embolisation to the heart and lungs is infrequently reported in the last 80 years. Iatrogenic cases of foreign body embolisation are very rare. Fifty 1-2 cm segments of Titanium rod were cut in an unconstrained manner and a novel method was used to calculate velocity. A high-speed camera (6,000 frames/s) was used to further measure velocity and study projectile motion. The wounding potential was investigated using lambs liver, high-speed photography and local dissection. Rod velocities were measured in excess of 23 m s(-1). Rods were seen to tumble end-over-end with a maximum speed of 560 revolutions/s. The maximum kinetic energy was 0.61 J which is approximately 2% that of a crossbow. This is sufficient to cause significant liver damage. The degree of surface damage and internal disruption was influenced by the orientation of the rod fragment at impact. An unconstrained cut segment of a Titanium rod has a significant potential to wound. Precautions should be taken to avoid this potentially disastrous but preventable complication.

  14. Absorbent product to absorb fluids. [for collection of human wastes

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

  15. Method and means of packaging nuclear fuel rods for handling

    DOEpatents

    Adam, Milton F.

    1979-01-01

    Nuclear fuel rods, especially spent nuclear fuel rods that may show physical distortion, are encased within a metallic enclosing structure by forming a tube about the fuel rod. The tube has previously been rolled to form an overlapping tubular structure and then unrolled and coiled about an axis perpendicular to the tube. The fuel rod is inserted into the tube as the rolled tube is removed from a coiled strip and allowed to reassume its tubular shape about the fuel rod. Rollers support the coiled strip in an open position as the coiled strip is uncoiled and allowed to roll about the fuel rod.

  16. An introduction to absorbent dressings.

    PubMed

    Jones, Menna Lloyd

    2014-12-01

    Exudate bathes the wound bed with a serous fluid that contains essential components that promote wound healing. However, excess exudate is often seen as a challenge for clinicians. Absorbent dressings are often used to aid in the management of exudate, with the aim of providing a moist but unmacerated environment. With so many different types of absorbent dressings available today-alongside making a holistic assessment-it is essential that clinicians also have the knowledge and skill to select the most appropriate absorbent dressing for a given patient.

  17. Self-Regulating Shock Absorber

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1995-01-01

    Mechanical shock absorber keeps frictional damping force within tolerable limit. Its damping force does not increase with coefficient of friction between energy-absorbing components; rather, frictional damping force varies only slightly. Relatively insensitive to manufacturing variations and environmental conditions altering friction. Does not exhibit high breakaway friction and consequent sharp increase followed by sharp decrease in damping force at beginning of stroking. Damping force in absorber does not vary appreciably with speed of stroking. In addition, not vulnerable to leakage of hydraulic fluid.

  18. Modeling and simulation performance of sucker rod beam pump

    SciTech Connect

    Aditsania, Annisa; Rahmawati, Silvy Dewi Sukarno, Pudjo; Soewono, Edy

    2015-09-30

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

  19. Modeling and simulation performance of sucker rod beam pump

    NASA Astrophysics Data System (ADS)

    Aditsania, Annisa; Rahmawati, Silvy Dewi; Sukarno, Pudjo; Soewono, Edy

    2015-09-01

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

  20. Light adaptation in retinal rods of the rabbit and two other nonprimate mammals

    PubMed Central

    1991-01-01

    The responses of rabbit rods to light were studied by drawing a single rod outer segment projecting from a small piece of retina into a glass pipette to record membrane current. The bath solution around the cells was maintained at near 40 degrees C. Light flashes evoked transient outward currents that saturated at up to approximately 20 pA. One absorbed photon produced a response of approximately 0.8 pA at peak. At the rising phase of the flash response, the relation between response amplitude and flash intensity (IF) had the exponential form 1-e-kappa FIF (where kappa F is a constant denoting sensitivity) expected from the absence of light adaptation. At the response peak, however, the amplitude-intensity relation fell slightly below the exponential form. At times after the response peak, the deviation was progressively more substantial. Light steps evoked responses that rose to a transient peak and rapidly relaxed to a lower plateau level. The response-intensity relation again indicated that light adaptation was insignificant at the early rising phase of the response, but became progressively more prominent at the transient peak and the steady plateau of the response. Incremental flashes superposed on a steady light of increasing intensity evoked responses that had a progressively shorter time-to- peak and faster relaxation, another sign of light adaptation. The flash sensitivity changed according to the Weber-Fechner relation (i.e., inversely) with background light intensity. We conclude that rabbit rods adapt to light in a manner similar to rods in cold-blooded vertebrates. Similar observations were made on cattle and rat rods. PMID:2037836

  1. Image analysis for measuring rod network properties

    NASA Astrophysics Data System (ADS)

    Kim, Dongjae; Choi, Jungkyu; Nam, Jaewook

    2015-12-01

    In recent years, metallic nanowires have been attracting significant attention as next-generation flexible transparent conductive films. The performance of films depends on the network structure created by nanowires. Gaining an understanding of their structure, such as connectivity, coverage, and alignment of nanowires, requires the knowledge of individual nanowires inside the microscopic images taken from the film. Although nanowires are flexible up to a certain extent, they are usually depicted as rigid rods in many analysis and computational studies. Herein, we propose a simple and straightforward algorithm based on the filtering in the frequency domain for detecting the rod-shape objects inside binary images. The proposed algorithm uses a specially designed filter in the frequency domain to detect image segments, namely, the connected components aligned in a certain direction. Those components are post-processed to be combined under a given merging rule in a single rod object. In this study, the microscopic properties of the rod networks relevant to the analysis of nanowire networks were measured for investigating the opto-electric performance of transparent conductive films and their alignment distribution, length distribution, and area fraction. To verify and find the optimum parameters for the proposed algorithm, numerical experiments were performed on synthetic images with predefined properties. By selecting proper parameters, the algorithm was used to investigate silver nanowire transparent conductive films fabricated by the dip coating method.

  2. Piston rod seal for a Stirling engine

    SciTech Connect

    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.

  3. Confinement stabilises single crystal vaterite rods.

    PubMed

    Schenk, Anna S; Albarracin, Eduardo J; Kim, Yi-Yeoun; Ihli, Johannes; Meldrum, Fiona C

    2014-05-11

    Single-crystals of vaterite, the least-stable anhydrous polymorph of CaCO3, are rare in biogenic and synthetic systems. We here describe the synthesis of high aspect ratio single crystal vaterite rods under additive-free conditions by precipitating CaCO3 within the cylindrical pores of track-etch membranes.

  4. Using the Rods for Structural Grammar.

    ERIC Educational Resources Information Center

    Chambers, Patrick

    The innovative use of a visual cueing device, or rods, in a second language class to represent the parts of speech and the grammatical structure of a sentence is explained and illustrated. The advantages found in it are that individual structures are not learned as isolated elements but rather as parts of a larger system, and that there is more…

  5. Genetics Home Reference: intranuclear rod myopathy

    MedlinePlus

    ... fibers and are important for muscle contraction. Attachment (binding) and release of the overlapping thick and thin filaments allows them to move relative to each other so that the muscles can contract. ACTA1 gene mutations that cause intranuclear rod myopathy ...

  6. CONTROL ROD ALLOY CONTAINING NOBLE METAL ADDITIONS

    DOEpatents

    Anderson, W.K.; Ray, W.E.

    1960-05-01

    Silver-base alloys suitable for use in the fabrication of control rods for neutronic reactors are given. The alloy consists of from 0.5 wt.% to about 1.5 wt.% of a noble metal of platinum, ruthenium, rhodium, osmium, or palladium, up to 10 wt.% of cadmium, from 2 to 20 wt.% indium, the balance being silver.

  7. Drop Ejection From an Oscillating Rod

    NASA Technical Reports Server (NTRS)

    Wilkes, E. D.; Basaran, O. A.

    1999-01-01

    The dynamics of a drop of a Newtonian liquid that is pendant from or sessile on a solid rod that is forced to undergo time-periodic oscillations along its axis is studied theoretically. The free boundary problem governing the time evolution of the shape of the drop and the flow field inside it is solved by a method of lines using a finite element algorithm incorporating an adaptive mesh. When the forcing amplitude is small, the drop approaches a limit cycle at large times and undergoes steady oscillations thereafter. However, drop breakup is the consequence if the forcing amplitude exceeds a critical value. Over a wide range of amplitudes above this critical value, drop ejection from the rod occurs during the second oscillation period from the commencement of rod motion. Remarkably, the shape of the interface at breakup and the volume of the primary drop formed are insensitive to changes in forcing amplitude. The interface shape at times close to and at breakup is a multi-valued function of distance measured along the rod axis and hence cannot be described by recently popularized one-dimensional approximations. The computations show that drop ejection occurs without the formation of a long neck. Therefore, this method of drop formation holds promise of preventing formation of undesirable satellite droplets.

  8. Adjustable solitary waves in electroactive rods

    NASA Astrophysics Data System (ADS)

    Wang, Y. Z.; Zhang, C. L.; Dai, H.-H.; Chen, W. Q.

    2015-10-01

    This paper presents an asymptotic analysis of solitary waves propagating in an incompressible isotropic electroactive circular rod subjected to a biasing longitudinal electric displacement. Several asymptotic expansions are introduced to simplify the rod governing equations. The boundary conditions on the lateral surface of the rod are satisfied from the asymptotic point of view. In the limit of finite-small amplitude and long wavelength, a set of ten simplified one-dimensional nonlinear governing equations is established. To validate our approach and the derivation, we compare the linear dispersion relation with the one directly derived from the three-dimensional linear theory in the limit of long wavelength. Then, by the reductive perturbation method, we deduce the far-field equation (i.e. the KdV equation). Finally, the leading order of the electroelastic solitary wave solution is presented. Numerical examples are provided to show the influences of the biasing electric displacement and material constants on the solitary waves. It is found that the biasing electric displacement can modulate the velocity of solitary waves with a prescribed amplitude in the electroactive rod, a very interesting result which may promote the particular application of solitary waves in solids with multi-field coupling.

  9. 49 CFR 236.793 - Rod, lock.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF..., attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse position....

  10. 49 CFR 236.793 - Rod, lock.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF..., attached to the front rod or lug of a switch, movable-point frog or derail, through which a locking plunger may extend when the switch points or derail are in the normal or reverse position....

  11. Monodisperse hard rods in external potentials.

    PubMed

    Bakhti, Benaoumeur; Karbach, Michael; Maass, Philipp; Müller, Gerhard

    2015-10-01

    We consider linear arrays of cells of volume V(c) populated by monodisperse rods of size σV(c),σ=1,2,..., subject to hardcore exclusion interaction. Each rod experiences a position-dependent external potential. In one application we also examine effects of contact forces between rods. We employ two distinct methods of exact analysis with complementary strengths and different limits of spatial resolution to calculate profiles of pressure and density on mesoscopic and microscopic length scales at thermal equilibrium. One method uses density functionals and the other statistically interacting vacancy particles. The applications worked out include gravity, power-law traps, and hard walls. We identify oscillations in the profiles on a microscopic length scale and show how they are systematically averaged out on a well-defined mesoscopic length scale to establish full consistency between the two approaches. The continuum limit, realized as V(c)→0,σ→∞ at nonzero and finite σV(c), connects our highest-resolution results with known exact results for monodisperse rods in a continuum. We also compare the pressure profiles obtained from density functionals with the average microscopic pressure profiles derived from the pair distribution function.

  12. Spontaneous emission and absorber theory

    NASA Astrophysics Data System (ADS)

    Pegg, David T.

    1997-01-01

    One of the long term interests of George Series was the construction of a theory of spontaneous emission which does not involve field quantisation. His approach was written in terms of atomic operators only and he drew a parallel with the Wheeler-Feynman absorber theory of radiation. By making a particular extra postulate, he was able to obtain the correct spontaneous emission rate and the Lamb shift reasonably simply and directly. An examination of his approach indicates that this postulate is physically reasonable and the need for it arises because quantisation in his theory occurs after the response of the absorber has been accounted for by means of the radiative reaction field. We review briefly an alternative absorber theory approach to spontaneous emission based on the direct action between the emitting atom and a quantised absorber, and outline some applications to more recent effects of interest in quantum optics.

  13. Guided tissue regeneration. Absorbable barriers.

    PubMed

    Wang, H L; MacNeil, R L

    1998-07-01

    Over the past 15 years, techniques aimed at regeneration of lost periodontal tissue have become widely used and accepted in clinical practice. Among these techniques are those which use the principles of guided tissue regeneration (GTR), wherein barriers (i.e., membranes) are used to control cell and tissue repopulation of the periodontal wound. A variety of non-absorbable and absorbable barriers have been developed and used for this purpose, with a trend in recent years toward increased use of absorbable GTR materials. This article describes the evolution of absorbable barrier materials and overview materials available for clinical use today. In addition, advantages and disadvantages of these materials are discussed, as well as possible new developments in barrier-based GTR therapy.

  14. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, W.H.

    1984-10-16

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system. 9 figs.

  15. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, William H.

    1984-01-01

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system.

  16. Perfect selective metamaterial solar absorbers.

    PubMed

    Wang, Hao; Wang, Liping

    2013-11-04

    In this work, we numerically investigate the radiative properties of metamaterial nanostructures made of two-dimensional tungsten gratings on a thin dielectric spacer and an opaque tungsten film from UV to mid-infrared region as potential selective solar absorbers. The metamaterial absorber with single-sized tungsten patches exhibits high absorptance in the visible and near-infrared region due to several mechanisms such as surface plasmon polaritons, magnetic polaritons, and intrinsic bandgap absorption of tungsten. Geometric effects on the resonance wavelengths and the absorptance spectra are studied, and the physical mechanisms are elucidated in detail. The absorptance could be further enhanced in a broader spectral range with double-sized metamaterial absorbers. The total solar absorptance of the optimized metamaterial absorbers at normal incidence could be more than 88%, while the total emittance is less than 3% at 100°C, resulting in total photon-to-heat conversion efficiency of 86% without any optical concentration. Moreover, the metamaterial solar absorbers exhibit quasi-diffuse behaviors as well as polarization independence. The results here will facilitate the design of novel highly efficient solar absorbers to enhance the performance of various solar energy conversion systems.

  17. VIEW EAST, EAST ELEVATION OF ECCENTRIC HOUSE, NOTE ROD LINES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW EAST, EAST ELEVATION OF ECCENTRIC HOUSE, NOTE ROD LINES EXITING THE BUILDING AND ROD LINES WITH SUPPORTS IN FOREGROUND LEFT. - South Penn Oil Company, G. M. Mead Lot 492 Lease, Morrison Run Field, Clarendon, Warren County, PA

  18. Looking Northwest Along South End of Rod Loading Building Including ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking Northwest Along South End of Rod Loading Building Including Mezzanine and Gad Loading Area - Hematite Fuel Fabrication Facility, Rod Loading Building, 3300 State Road P, Festus, Jefferson County, MO

  19. 5. DETAIL OF ROD MILL BASE AND CONVEYOR BELT SUPPORT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DETAIL OF ROD MILL BASE AND CONVEYOR BELT SUPPORT, EAST VIEW. - Vanadium Corporation of America (VCA) Naturita Mill, Grinding Rod Mill, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

  20. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Identification. An intramedullary fixation rod is a device intended to be implanted that consists of a rod made of alloys such as cobalt-chromium-molybdenum and stainless steel. It is inserted into the...

  1. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Identification. An intramedullary fixation rod is a device intended to be implanted that consists of a rod made of alloys such as cobalt-chromium-molybdenum and stainless steel. It is inserted into the...

  2. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Identification. An intramedullary fixation rod is a device intended to be implanted that consists of a rod made of alloys such as cobalt-chromium-molybdenum and stainless steel. It is inserted into the...

  3. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) Identification. An intramedullary fixation rod is a device intended to be implanted that consists of a rod made of alloys such as cobalt-chromium-molybdenum and stainless steel. It is inserted into the...

  4. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) Identification. An intramedullary fixation rod is a device intended to be implanted that consists of a rod made of alloys such as cobalt-chromium-molybdenum and stainless steel. It is inserted into the...

  5. 11. Detail showing stay rods and westerly Samson post; view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Detail showing stay rods and westerly Samson post; view to west. Note slackness of stay rods while draw-span is closed. - Summer Street Bridge, Spanning Reserved Channel, Boston, Suffolk County, MA

  6. Stimulus-evoked outer segment changes in rod photoreceptors

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Lu, Yiming; Gai, Shaoyan; Yao, Xincheng

    2016-06-01

    Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation.

  7. 13. SOUTHEAST TO SUCKER ROD WORK BENCH AND WOODEN SUCKER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. SOUTHEAST TO SUCKER ROD WORK BENCH AND WOODEN SUCKER ROD STORAGE RACKS ALONG EAST WALL OF FACTORY INTERIOR. AT THIS BENCH WORKERS RIVETED THREADED WROUGHT IRON CONNECTORS TO THE ENDS OF 20' LONG WOODEN SUCKER RODS (THE RODS WHICH EXTEND DOWNWARD IN THE WELL FROM THE GROUND SURFACE TO PISTON DISPLACEMENT PUMPS WHICH ACTUALLY ELEVATE WATER TO THE SURFACE). ROZNOR HEATER AT THE FAR RIGHT WAS ADDED CIRCA 1960. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  8. Viscosity of concentrated suspensions of sphere/rod mixtures

    SciTech Connect

    Mor, R.; Gottlieb, M.; Graham, A.L.; Mondy, L.A.

    1996-05-01

    This paper discusses the viscosity of concentrated suspensions of sphere/rod mixtures by adopting the Thomas relations for spheres and Milliken`s for randomly oriented rods with aspect ratio of 20. The relative viscosity of a mixed suspension may now be calculated for any combination of rods (of aspect ratio 20) and spheres.

  9. CONTROL ROD DRIVE MECHANISM FOR A NUCLEAR REACTOR

    DOEpatents

    Hawke, B.C.; Liederbach, F.J.; Lones, W.

    1963-05-14

    A lead-screw-type control rod drive featuring an electric motor and a fluid motor arranged to provide a selectably alternative driving means is described. The electric motor serves to drive the control rod slowly during normal operation, while the fluid motor, assisted by an automatic declutching of the electric motor, affords high-speed rod insertion during a scram. (AEC)

  10. The Galveston technique using Luque or Cotrel-Dubousset rods.

    PubMed

    Lonstein, J E

    1994-04-01

    The Galveston technique for pelvic fixation in long fusions to the sacrum in neuromuscular and adult scoliosis is an effective technique to help obtain a solid fusion. With careful technique and accurate rod bending, rod insertion, rod contouring, and wire tightening, excellent fixation is obtained that maximizes the fusion rate.

  11. Detection of Microcracks in Trunnion Rods Using Ultrasonic Guided Waves

    DTIC Science & Technology

    2015-07-01

    compress the surrounding concrete and prevent it from experiencing excessive destructive tensile forces. These rods are now experiencing ongoing failures...5 Figure 4. Full-scale 4-rod test bed during construction and concrete ...diameter grease-embedded trunnion anchor rod with concrete termination. ...................... 14 Figure 11. Variation in load and the resulting

  12. Vibrational spraying of liquid by a thin rod

    NASA Astrophysics Data System (ADS)

    Aleksandrov, V. A.

    2008-02-01

    The phenomenon of liquid spraying by a thin rod bent at a right angle and excited with a piezoelectric transducer at one end is observed when the rod touches the open liquid surface at the bending site. The spraying may be accompanied by the formation of a liquid jet, which is emitted from the free end of the bent rod.

  13. 77 FR 1504 - Stainless Steel Wire Rod From India

    Federal Register 2010, 2011, 2012, 2013, 2014

    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...

  14. Rod Has High Tensile Strength And Low Thermal Expansion

    NASA Technical Reports Server (NTRS)

    Smith, D. E.; Everton, R. L.; Howe, E.; O'Malley, M.

    1996-01-01

    Thoriated tungsten extension rod fabricated to replace stainless-steel extension rod attached to linear variable-differential transformer in gap-measuring gauge. Threads formed on end of rod by machining with special fixtures and carefully chosen combination of speeds and feeds.

  15. Mushroom plasmonic metamaterial infrared absorbers

    SciTech Connect

    Ogawa, Shinpei Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-26

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF{sub 2} etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  16. Mushroom plasmonic metamaterial infrared absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-01

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  17. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  18. Carbon Absorber Retrofit Equipment (CARE)

    SciTech Connect

    Klein, Eric

    2015-12-23

    During Project DE-FE0007528, CARE (Carbon Absorber Retrofit Equipment), Neumann Systems Group (NSG) designed, installed and tested a 0.5MW NeuStream® carbon dioxide (CO2) capture system using the patented NeuStream® absorber equipment and concentrated (6 molal) piperazine (PZ) as the solvent at Colorado Springs Utilities’ (CSU’s) Martin Drake pulverized coal (PC) power plant. The 36 month project included design, build and test phases. The 0.5MW NeuStream® CO2 capture system was successfully tested on flue gas from both coal and natural gas combustion sources and was shown to meet project objectives. Ninety percent CO2 removal was achieved with greater than 95% CO2product purity. The absorbers tested support a 90% reduction in absorber volume compared to packed towers and with an absorber parasitic power of less than 1% when configured for operation with a 550MW coal plant. The preliminary techno-economic analysis (TEA) performed by the Energy and Environmental Research Center (EERC) predicted an over-the-fence cost of $25.73/tonne of CO2 captured from a sub-critical PC plant.

  19. Theory of thin-walled rods

    NASA Technical Reports Server (NTRS)

    Goldenveizer, A L

    1951-01-01

    Starting with the Love equations for bending of extensible shells, "principal stress states" are sought for a thin-walled rod of arbitrary but open cross section. Principal stress states exclude those local states arising from end conditions which damp out with distance from the ends. It is found that for rods of intermediate length, long enough to avoid local bending at a support, and short enough that elementary torsion and bending are not the most significant stress states, four principal states exist. Three of these states are associated with the planar distribution of axial stress and are equivalent to the engineering theory of extension and bending of solid sections. The fourth state resembles that which has been called in the literature "bending stress due to torsional", except that cross sections are permitted to bend and the shear along the center line of the cross section is permitted to differ from zero.

  20. Instabilities of a rotating helical rod

    NASA Astrophysics Data System (ADS)

    Park, Yunyoung; Ko, William; Kim, Yongsam; Lim, Sookkyung

    2016-11-01

    Bacteria such as Escherichia coli and Vibrio alginolyticus have helical flagellar filament. By rotating a motor, which is located at the bottom end of the flagellar filament embedded in the cell body, CCW or CW, they swim forward or backward. We model a left-handed helix by the Kirchhoff rod theory and use regularized Stokes formulation to study an interaction between the surrounding fluid and the flagellar filament. We perform numerical studies focusing on relations between physical parameters and critical angular frequency of the motor, which separates overwhiring from twirling. We are also interested in the buckling instability of the hook, which is very flexible elastic rod. By measuring buckling angle, which is an angle between rotational axis and helical axis, we observe the effects of physical parameters on buckling of the hook.

  1. Critical heat flux predictions in rod bundles

    SciTech Connect

    Kao, S.P.; Kazimi, M.S.

    1983-01-01

    The prediction of critical heat flux (CHF) in rod bundles has been studied with both subchannel and bundle-average methods. The correlations of Biasi, Bowring, CISE-4, and Barnett were considered. The General Electric 9-rod bundle CHF data were used in the comparisons. Calculations were performed by the two-fluid subchannel code THERMIT-2. The results indicate that the subchannel method yields more conservative CHF predictions than the bundleaverage method. This is attributed to the two-phase turbulent mixing phenomenon in the bundle, which can be modeled only on a subchannel basis. The results also indicate that the CISE-4 correlation had the smallest error in prediction of transition boiling for both subchannel and bundle-average methods.

  2. Nuclear reactor fuel rod attachment system

    DOEpatents

    Christiansen, David W.

    1982-01-01

    A reusable system for removably attaching a nuclear reactor fuel rod (12) to a support member (14). A locking cap (22) is secured to the fuel rod (12) and a locking strip (24) is fastened to the support member (14). The locking cap (22) has two opposing fingers (24a and 24b) shaped to form a socket having a body portion (26). The locking strip has an extension (36) shaped to rigidly attach to the socket's body portion (26). The locking cap's fingers are resiliently deflectable. For attachment, the locking cap (22) is longitudinally pushed onto the locking strip (24) causing the extension (36) to temporarily deflect open the fingers (24a and 24b) to engage the socket's body portion (26). For removal, the process is reversed.

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

    PubMed

    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.

  4. Intranuclear rods myopathy with autonomic dysfunction.

    PubMed

    Chou, Po-Ching; Liang, Wen-Chen; Nonaka, Ikuya; Mitsuhashi, Satomi; Nishino, Ichizo; Jong, Yuh-Jyh

    2013-08-01

    Intranuclear rods myopathy (IRM), a variant of nemaline myopathy (NM), is characterized by rod structure in the myonuclei. Patients with IRM present with similar symptoms to those of severe infantile-type NM but have worse outcome. Several extramuscular manifestations have been reported in NM but no dysautonomia. We herein report a 2-year-old girl with IRM and a heterozygous mutation, c.430C>T (p.L144F) in ACTA1. During the infancy, the patient showed severe diaphoresis and facial flushing. Arrhythmia and hypertension with the precipitating factors of feeding, defecation, and urination were observed. Sympathetic antagonist was prescribed and showed some effectiveness. Our report may widen the clinical spectrum of IRM. It also reminds clinicians that autonomic dysfunction may occur in patients with IRM or other actinopathies and appropriate treatment may be necessary.

  5. A survey of laser lightning rod techniques

    NASA Technical Reports Server (NTRS)

    Barnes, Arnold A., Jr.; Berthel, Robert O.

    1991-01-01

    The work done to create a laser lightning rod (LLR) is discussed. Some ongoing research which has the potential for achieving an operational laser lightning rod for use in the protection of missile launch sites, launch vehicles, and other property is discussed. Because of the ease with which a laser beam can be steered into any cloud overhead, an LLR could be used to ascertain if there exists enough charge in the clouds to discharge to the ground as triggered lightning. This leads to the possibility of using LLRs to test clouds prior to launching missiles through the clouds or prior to flying aircraft through the clouds. LLRs could also be used to probe and discharge clouds before or during any hazardous ground operations. Thus, an operational LLR may be able to both detect such sub-critical electrical fields and effectively neutralize them.

  6. Fluid Dynamics in Sucker Rod Pumps

    SciTech Connect

    Cutler, R.P.; Mansure, A.J.

    1999-01-14

    Sucker rod pumps are installed in approximately 90% of all oil wells in the U.S. Although they have been widely used for decades, there are many issues regarding the fluid dynamics of the pump that have not been fully investigated. A project was conducted at Sandia National Laboratories to develop unimproved understanding of the fluid dynamics inside a sucker rod pump. A mathematical flow model was developed to predict pressures in any pump component or an entire pump under single-phase fluid and pumping conditions. Laboratory flow tests were conducted on instrumented individual pump components and on a complete pump to verify and refine the model. The mathematical model was then converted to a Visual Basic program to allow easy input of fluid, geometry and pump parameters and to generate output plots. Examples of issues affecting pump performance investigated with the model include the effects of viscosity, surface roughness, valve design details, plunger and valve pressure differentials, and pumping rate.

  7. A Double-Strand Elastic Rod Theory

    NASA Astrophysics Data System (ADS)

    Moakher, Maher; Maddocks, John H.

    2005-07-01

    Motivated by applications in the modeling of deformations of the DNA double helix, we construct a continuum mechanics model of two elastically interacting elastic strands. The two strands are described in terms of averaged, or macroscopic, variables plus an additional small, internal or microscopic, perturbation. We call this composite structure a birod. The balance laws for the macroscopic configuration variables of the birod can be cast in the form of a classic Cosserat rod model with coupling to the internal balance laws through the constitutive relations. The internal balance laws for the microstructure variables also take a mathematical form analogous to that for a Cosserat rod, but with coupling to the macroscopic system through terms corresponding to distributed force and couple loads.

  8. Statistical properties of a folded elastic rod

    NASA Astrophysics Data System (ADS)

    Bayart, Elsa; Deboeuf, Stéphanie; Boué, Laurent; Corson, Francis; Boudaoud, Arezki; Adda-Bedia, Mokhtar

    2010-03-01

    A large variety of elastic structures naturally seem to be confined into environments too small to accommodate them; the geometry of folded structures span a wide range of length-scales. The elastic properties of these confined systems are further constrained by self-avoidance as well as by the dimensionality of both structures and container. To mimic crumpled paper, we devised an experimental setup to study the packing of a dimensional elastic object in 2D geometries: an elastic rod is folded at the center of a circular Hele-Shaw cell by a centripetal force. The initial configuration of the rod and the acceleration of the rotating disk allow to span different final folded configurations while the final rotation speed controls the packing intensity. Using image analysis we measure geometrical and mechanical properties of the folded configurations, focusing on length, curvature and energy distributions.

  9. Variable flow control for a nuclear reactor control rod

    DOEpatents

    Carleton, Richard D.; Bhattacharyya, Ajay

    1978-01-01

    A variable flow control for a control rod assembly of a nuclear reactor that depends on turbulent friction though an annulus. The annulus is formed by a piston attached to the control rod drive shaft and a housing or sleeve fitted to the enclosure housing the control rod. As the nuclear fuel is burned up and the need exists for increased reactivity, the control rods are withdrawn, which increases the length of the annulus and decreases the rate of coolant flow through the control rod assembly.

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

    SciTech Connect

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

    2007-07-01

    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

  11. Rod Driven Frequency Entrainment and Resonance Phenomena

    PubMed Central

    Salchow, Christina; Strohmeier, Daniel; Klee, Sascha; Jannek, Dunja; Schiecke, Karin; Witte, Herbert; Nehorai, Arye; Haueisen, Jens

    2016-01-01

    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 to 2.30∗α. Three hundred and six-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. PMID:27588002

  12. Rod Driven Frequency Entrainment and Resonance Phenomena.

    PubMed

    Salchow, Christina; Strohmeier, Daniel; Klee, Sascha; Jannek, Dunja; Schiecke, Karin; Witte, Herbert; Nehorai, Arye; Haueisen, Jens

    2016-01-01

    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 to 2.30(∗)α. Three hundred and six-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.

  13. Analysis of Double-encapsulated Fuel Rods

    SciTech Connect

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

    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.

  14. Low temperature selective absorber research

    NASA Astrophysics Data System (ADS)

    Herzenberg, S. A.; Silberglitt, R.

    1982-04-01

    Research carried out since 1979 on selective absorbers is surveyed, with particular attention given to the low-temperature coatings seen as promising for flat plate and evacuated tube applications. The most thoroughly investigated absorber is black chrome, which is highly selective and is the most durable low-temperature absorber. It is believed that other materials, because of their low cost and lower content of strategic materials, may eventually supplant black chrome. Among these candidates are chemically converted black nickel; anodically oxidized nickel, zinc, and copper composites; and nickel or other low-cost multilayer coatings. In reviewing medium and high-temperature research, black chrome, multilayer coatings and black cobalt are seen as best medium-temperature candidates. For high temperatures, an Al2O3/Pt-Al203 multilayer composite or the zirconium diboride coating is preferred.

  15. Interfacial phenomena in hard-rod fluids

    NASA Astrophysics Data System (ADS)

    Shundyak, K. Y.

    2004-05-01

    This thesis addresses questions of interfacial ordering in hard-rod fluids at coexistence of the isotropic and nematic phases and in their contact with simple model substrates. It is organized as follows. Chapter II provides some background information about the relation between the statistical mechanical and thermodynamical level of descriptions of bulk hard-rod fluids, as well as introduces the asymptotically exact Onsager model, and some basic facts of interfacial thermodynamics. Chapter III represents studies of the simplest free IN interface in a fluid of monodisperse Onsager hard rods. For the analysis of this system we develop an efficient perturbative method to determine the (biaxial) one-particle distribution function in inhomogeneous systems. Studies of the free planar isotropic-nematic interfaces are continued in Chapter IV, where they are considered in binary mixtures of hard rods. For sufficiently different particle shapes the bulk phase diagrams of these mixtures exhibit a triple point, where an isotropic (I) phase coexists with two nematic phases (N1 and N2) of different composition. For all explored mixtures we find that upon approach of the triple point the IN2 interface shows complete wetting by an intervening N1 film. We compute the surface tension of isotropic-nematic interfaces, and find a remarkable increase with fractionation. These studies are complemented by an analysis of bulk phase behavior and interfacial properties of nonadditive binary mixtures of thin and thick hard rods in Chapter V. The formulation of this model was motivated by recent experiments in the group of Fraden, who explored the phase behavior of a mixture of viruses with different effective diameters. In our model, species of the same types are considered as interacting with the hard-core repulsive potential, whereas the excluded volume for dissimilar rods is taken to be larger (smaller) then for the pure hard rods. Such a nonadditivity enhances (reduces) fractionation at

  16. Experiments with a plasma-filled rod-pinch diode on the MIG generator

    NASA Astrophysics Data System (ADS)

    Sorokin, S. A.

    2011-07-01

    Experimental data for creating an X-ray source several millimeters in size on the basis of a plasmafilled rod-pinch diode are reported. Experiments are carried out on the MIG high-current generator. A voltage pulse applied to the diode is sharpened and shortened by injecting plasma into the interelectrode gap up to the plasma-filled diode. Radiation extraction from the vacuum chamber in the paraxial direction is provided by inverting the positions of the cathode and anode using a post-hole vacuum convolute. It is demonstrated that the energy of a low-impedance high-current generator can be deposited with a high efficiency into an electron beam focused on the 1-mm2 tip of the rod-shaped anode. With a tapered tungsten rod 1.5 mm in diameter used as an anode, a pulsed X-ray source about 1 mm in size generating 30-ns-long pulses is obtained. The absorbed dose per pulse measured with a LiF thermoluminescent dosimeter behind a 5-mm-thick aluminum screen 1 m away from the source reaches 0.042 Gy.

  17. Measurements of lightning rod responses to nearby strikes

    NASA Astrophysics Data System (ADS)

    Moore, C. B.; Aulich, G. D.; Rison, W.

    2000-05-01

    Following Benjamin Franklin's invention of the lightning rod, based on his discovery that electrified objects could be discharged by approaching them with a metal needle in hand, conventional lightning rods in the U.S. have had sharp tips. In recent years, the role of the sharp tip in causing a lightning rod to act as a strike receptor has been questioned leading to experiments in which pairs of various sharp-tipped and blunt rods have been exposed beneath thunderclouds to determine the better strike receptor. After seven years of tests, none of the sharp Franklin rods or of the so-called “early streamer emitters” has been struck, but 12 blunt rods with tip diameters ranging from 12.7 mm to 25.4 mm have taken strikes. Our field experiments and our analyses indicate that the strike-reception probabilities of Franklin's rods are greatly increased when their tips are made moderately blunt.

  18. Rod-cone interactions and analysis of retinal disease.

    PubMed Central

    Arden, G B; Hogg, C R

    1985-01-01

    Cone flicker threshold rises as the rods dark adapt, though the cone threshold to continuous light remains constant. The rise is normally about 1 log unit, but in certain patients who complain of night blindness it may be as great as 2.5 log units. In these persons the kinetics of the rod-cone interaction are those of the recovery of rod sensitivity. The rods impose a low-pass filter on the cones. This effect is absent in congenital nyctalopia and X-linked retinoschisis. We suggest that cone flicker is maintained through a feedback system involving horizontal cells, and when the rod dark current returns in dark adaptation this feedback is altered. Rod cone interaction thus tests rod dark current, and cases of abnormal interaction in patients with retinitis pigmentosa occur, which indicate that the transduction mechanism and the membrane dark current may be differentially affected. Images PMID:3873959

  19. On the metabolism of the rod outer segments.

    PubMed Central

    Carretta, A; Cavaggioni, A

    1976-01-01

    1. The high energy phosphate esters available for the luminescent reaction of the firefly lantern extract correspond, in the dark adapted rods of the frog, to 7 X 10(-16) mole of ATP per rod, corresponding to ca. 1-4 mM. 2. Rods isolated from light adapted eyes contain a smaller amount. 3. The high energy phosphate esters are reduced spontaneously at a rate of 50% in 24 min, in the isolated rods in darkness. 4. Bleaching a few per cent of the rhodopsin molecules of a rod suspension induces a 60% decrease achieved in less than 12 sec. 5. The ionophore A23187 decreases the high energy phosphate esters when the extracellular free Ca concentration is greater than 10(-7) M, suggesting that ATP is consumed in pumping Ca ions out of the rods, or into the disks contained in the rods, or both. PMID:781215

  20. Nuclear thermionic converter. [tungsten-thorium oxide rods

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.; Mondt, J. F. (Inventor)

    1977-01-01

    Efficient nuclear reactor thermionic converter units are described which can be constructed at low cost and assembled in a reactor which requires a minimum of fuel. Each converter unit utilizes an emitter rod with a fluted exterior, several fuel passages located in the bulges that are formed in the rod between the flutes, and a collector receiving passage formed through the center of the rod. An array of rods is closely packed in an interfitting arrangement, with the bulges of the rods received in the recesses formed between the bulges of other rods, thereby closely packing the nuclear fuel. The rods are constructed of a mixture of tungsten and thorium oxide to provide high power output, high efficiency, high strength, and good machinability.

  1. Adaptive inertial shock-absorber

    NASA Astrophysics Data System (ADS)

    Faraj, Rami; Holnicki-Szulc, Jan; Knap, Lech; Seńko, Jarosław

    2016-03-01

    This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated.

  2. Damage tolerant light absorbing material

    DOEpatents

    Lauf, R.J.; Hamby, C. Jr.; Akerman, M.A.; Seals, R.D.

    1993-09-07

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, is prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000 C to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm[sup 3]. 9 figures.

  3. Damage tolerant light absorbing material

    DOEpatents

    Lauf, Robert J.; Hamby, Jr., Clyde; Akerman, M. Alfred; Seals, Roland D.

    1993-01-01

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm.sup.3.

  4. Tuned dynamic absorber for split Stirling cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Veprik, Alexander; Tuito, Avi

    2016-05-01

    Tuned dynamic absorbers (TDA) find use, in particular, for attenuating tonal vibration export produced by the moving components of cryogenic cooler. For the best performance, the resonant frequency of TDA needs to be essentially equal the driving frequency; accurate frequency match is favorably achieved by minimizing the cooler induced vibration by adjusting the driving frequency. For the best performance, the design of TDA needs to ensure minimum damping ratio; this is achievable by using planar flexural bearings having zero friction anchoring features. Accurate evaluation of effective mass, damping ratio and frequency is needed for TDA characterization during development and manufacturing. This data may be also important for the dynamic modelling. The authors are exploring the express method requiring no physical access to the proof mass of TDA. In this approach, the TDA is mounted upon the low frequency vibration mounted rod, the dynamic properties of TDA are then evaluated using the frequency response function - local accelerance - captured on the above rod using accelerometer, instrumented modal hammer and dual-channel signal analyzer. The authors are presenting the TDA design, outcomes of full-scale experimentation on dynamic properties evaluation and attained performance.

  5. Spherical Joint Piston and Connecting Rod Developed

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Under an interagency agreement with the Department of Energy, the NASA Lewis Research Center manages a Heavy-Duty Diesel Engine Technology (HDET) research program. The overall program objectives are to reduce fuel consumption through increased engine efficiency, reduce engine exhaust emissions, and provide options for the use of alternative fuels. The program is administered with a balance of research contracts, university research grants, and focused in-house research. The Cummins Engine Company participates in the HDET program under a cost-sharing research contract. Cummins is researching and developing in-cylinder component technologies for heavy-duty diesel engines. An objective of the Cummins research is to develop technologies for a low-emissions, 55-percent thermal efficiency (LE-55) engine. The best current-production engines in this class achieve about 46-percent thermal efficiency. Federal emissions regulations are driving this technology. Regulations for heavy duty diesel engines were tightened in 1994, more demanding emissions regulations are scheduled for 1998, and another step is planned for 2002. The LE-55 engine emissions goal is set at half of the 1998 regulation level and is consistent with plans for 2002 emissions regulations. LE-55 engine design requirements to meet the efficiency target dictate a need to operate at higher peak cylinder pressures. A key technology being developed and evaluated under the Cummins Engine Company LE-55 engine concept is the spherical joint piston and connecting rod. Unlike conventional piston and connecting rod arrangements which are joined by a pin forming a hinged joint, the spherical joint piston and connecting rod use a ball-and-socket joint. The ball-and-socket arrangement enables the piston to have an axisymmetric design allowing rotation within the cylinder. The potential benefits of piston symmetry and rotation are reduced scuffing, improved piston ring sealing, improved lubrication, mechanical and thermal

  6. Between a Map and a Data Rod

    NASA Technical Reports Server (NTRS)

    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

  7. The Effect of Pitch, Burnup, and Absorbers on a TRIGA Spent-Fuel Pool Criticality Safety

    SciTech Connect

    Logar, Marjan; Jeraj, Robert; Glumac, Bogdan

    2003-02-15

    It has been shown that supercriticality might occur for some postulated accident conditions at the TRIGA spent-fuel pool. However, the effect of burnup was not accounted for in previous studies. In this work, the combined effect of fuel burnup, pitch among fuel elements, and number of uniformly mixed absorber rods for a square arrangement on the spent-fuel pool k{sub eff} is investigated.The Monte Carlo computer code MCNP4B with the ENDF-B/VI library and detailed three dimensional geometry was used. The WIMS-D code was used to model the isotopic composition of the standard TRIGA and FLIP fuel for 5, 10, 20 and 30% burnup level and 2- and 4-yr cooling time.The results show that out of the three studied effects, pitch from contact (3.75 cm) up to rack design pitch (8 cm), number of absorbers from zero to eight, and burnup up to 30%, the pitch has the greatest influence on the multiplication factor k{sub eff}. In the interval in which the pitch was changed, k{sub eff} decreased for up to {approx}0.4 for standard and {approx}0.3 for FLIP fuel. The number of absorber rods affects the multiplication factor much less. This effect is bigger for more compact arrangements, e.g., for contact of standard fuel elements with eight absorber rods among them, k{sub eff} values are smaller for {approx}0.2 ({approx}0.1 for FLIP) than for arrangements without absorber rods almost regardless of the burnup. The effect of burnup is the smallest. For standard fuel elements, it is {approx}0.1 for almost all pitches and numbers of absorbers. For FLIP fuel, it is smaller for a factor of 3, but increases with the burnup for compact arrangements. Cooling time of fuel has just a minor effect on the k{sub eff} of spent-fuel pool and can be neglected in spent-fuel pool design.

  8. Counterflow absorber for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

  9. Metamaterial Absorbers for Microwave Detection

    DTIC Science & Technology

    2015-06-01

    a) Depiction of metamaterial array of square resonators atop FR4. (b) Metamaterial dimensions and structure...comparison for varying resonator array dimension sizes. ..............23 Figure 12. Absorption derived from raw reflection data...36 x Figure 23. Metamaterial absorber array where resonator dimensions control the detection frequencies and

  10. Oil and fat absorbing polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  11. [Resorbable rods and screws for fixation of ankle fractures. A randomized clinical prospective study].

    PubMed

    Springer, M A; van Binsbergen, E A; Patka, P; Bakker, F C; Haarman, H J

    1998-05-01

    A prospective randomized clinical trial was performed to evaluate the use of self-reinforced absorbable composites (Biofix) in the fixation of ankle fractures. The aim of this study was to demonstrate that fixation with Biofix rods and screws is as good as the standard A.O. fixation. The benefits of Biofix rods and screws are: a reduction in costs since no secondary operation is needed, prevention of stress-shielding and thereby diminishing the risk of bone porosity. Patients aged between 16 and 75 years old with closed, non-comminuted fractures of the lateral and/or medial malleolus and dislocation of the fracture fragments greater than 2 mm were included in the study. 22 patients were treated with Biofix rods and screws and the control group of 19 patients with a standard technique. After 3, 6 and 12 months, rontgenograms were taken. At the same time functional results were evaluated following the criteria of Olerud and Molander. Two patients were withdrawn from the trial for non-medical reasons. 22 patients (12 from the Biofix group, 10 from the AO group) operated two or more years ago were contacted to see if any complications had occurred since they were last seen. In 4 cases a Biofix screw broke down just beneath the head during insertion. This did not result in an insufficient fixation of the fracture. There were no early post-operative complications. The functional and rontgenological results in both groups were equal. In three cases a sterile sinus developed at the site of screw insertion. Biofix rods and screws, made of polylactic acid, are a good alternative for the fixation of fractures of the ankle. The use of resorbable fracture fixation material has the advantage that a second operation to remove osteosynthesis material is not necessary. The long term results are good. There is, however, a possibility of development of tissue reaction to the resorbable material.

  12. Rod photoreceptor-specific gene expression in human retinoblastoma cells.

    PubMed Central

    Di Polo, A; Farber, D B

    1995-01-01

    Retinoblastoma cells in culture have previously been shown to express cone-specific genes but not their rod counterparts. We have detected the messages for the rod alpha, beta, and gamma subunits of cGMP phosphodiesterase (PDE), the rod alpha subunit of transducin, rod opsin, and the cone alpha' subunit of PDE in RNA of human Y-79 retinoblastoma cells by reverse transcription-PCR. Quantitative analysis of the mRNAs for the rod alpha and cone alpha' PDE subunits revealed that they were expressed at comparable levels; however, the transcript encoding the rod beta PDE subunit was 10 times more abundant in these cells. Northern hybridization analysis of Y-79 cell RNA confirmed the presence of the transcripts for rod and cone PDE catalytic subunits. To test whether the transcriptional machinery required for the expression of rod-specific genes was endogenous in Y-79 retinoblastoma cells, cultures were transfected with a construct containing the promoter region of the rod beta PDE subunit gene attached to the firefly luciferase reporter vector. Significant levels of reporter enzyme activity were observed in the cell lysates. Our results demonstrate that the Y-79 retinoblastoma cell line is a good model system for the study of transcriptional regulation of rod-specific genes. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7732024

  13. PDRD (SR13046) TRITIUM PRODUCTION FINAL REPORT

    SciTech Connect

    Smith, P.; Sheetz, S.

    2013-09-30

    Utilizing the results of Texas A&M University (TAMU) senior design projects on tritium production in four different small modular reactors (SMR), the Savannah River National Laboratory’s (SRNL) developed an optimization model evaluating tritium production versus uranium utilization under a FY2013 plant directed research development (PDRD) project. The model is a tool that can evaluate varying scenarios and various reactor designs to maximize the production of tritium per unit of unobligated United States (US) origin uranium that is in limited supply. The primary module in the model compares the consumption of uranium for various production reactors against the base case of Watts Bar I running a nominal load of 1,696 tritium producing burnable absorber rods (TPBARs) with an average refueling of 41,000 kg low enriched uranium (LEU) on an 18 month cycle. After inputting an initial year, starting inventory of unobligated uranium and tritium production forecast, the model will compare and contrast the depletion rate of the LEU between the entered alternatives. This is an annual tritium production rate of approximately 0.059 grams of tritium per kilogram of LEU (g-T/kg-LEU). To date, the Nuclear Regulatory Commission (NRC) license has not been amended to accept a full load of TPBARs so the nominal tritium production has not yet been achieved. The alternatives currently loaded into the model include the three light water SMRs evaluated in TAMU senior projects including, mPower, Holtec and NuScale designs. Initial evaluations of tritium production in light water reactor (LWR) based SMRs using optimized loads TPBARs is on the order 0.02-0.06 grams of tritium per kilogram of LEU used. The TAMU students also chose to model tritium production in the GE-Hitachi SPRISM, a pooltype sodium fast reactor (SFR) utilizing a modified TPBAR type target. The team was unable to complete their project so no data is available. In order to include results from a fast reactor, the SRNL

  14. OVI absorbers in SDSS spectra

    NASA Astrophysics Data System (ADS)

    Frank, Stephan

    We conducted a systematic search for signatures of the Intergalactic Medium (IGM) in Quasar spectra of the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3), focusing on finding intervening absorbers via detection of their O VI doublet. We present a search algorithm, and criteria for distinguishing candidates from spurious Lyman a forest lines. In addition, we compare our findings with simulations of the Lyman a forest in order to estimate the detectability of O VI doublets over various redshift intervals. We obtain a sample of 1866 O VI doublet candidates with rest-frame equivalent width >= 0.05 λ in 855 AGN spectra (out of 3702 objects with redshifts in the range accessible for O VI detection). This sample is subdivided into 3 groups according to the likelihood of being real and the potential for follow-up observation of the candidate. The group with the cleanest and most secure candidates is comprised of 145 candidates. 69 of these reside at a velocity separation >= 5000 km/s from the QSO, and can therefore be classified tentatively as intervening absorbers. Most of these absorbers have not been picked up by earlier, automated QSO absorption line detection algorithms. This sample increases the number of known O VI absorbers at redshifts beyond z abs >= 2.7 substantially. We propose to obtain observations of some of the candidates with the best signatures for O VI doublets with high signal-to-noise and high resolution in order to better constrain the physical state of the absorbers. We then focused on a subsample of 387 AGN sightlines with an average S/N >= 5: 0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r >= 0:19 ? A for the O VI 1032 λ component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density DN/Dz for redshifts z abs >= 2:8. With extensive Monte Carlo simulations we quantify the losses of absorbers due to blending

  15. Visual transduction in human rod photoreceptors.

    PubMed

    Kraft, T W; Schneeweis, D M; Schnapf, J L

    1993-05-01

    1. Photocurrents were recorded with suction electrodes from rod photoreceptors of seven humans. 2. Brief flashes of light evoked transient outward currents of up to 20 pA. With increasing light intensity the peak response amplitude increased along an exponential saturation function. A half-saturating peak response was evoked by approximately sixty-five photoisomerizations. 3. Responses to brief dim flashes rose to a peak in about 200 ms. The waveform was roughly like the impulse response of a series of four to five low-pass filters. 4. The rising phases of the responses to flashes of increasing strength were found to fit with a biochemical model of phototransduction with an 'effective delay time' and 'characteristic time' of about 2 and 800 ms, respectively. 5. Spectral sensitivities were obtained over a wavelength range from 380 to 760 nm. The action spectrum, which peaked at 495 nm, followed the template described for photoreceptors in the macaque retina. Variation between rods in the position of the spectrum on the wavelength axis was small. 6. The scotopic luminosity function derived from human psychophysical experiments was found to agree well with the measured rod action spectrum after adjustments were made for lens absorption and photopigment self-screening in the intact eye. 7. Responses to steps of light rose monotonically to a maintained level, showing little or no relaxation. Nevertheless, the relationship between light intensity and steady-state response amplitude was shallower than that expected from simple response saturation. This is consistent with an adaptation mechanism acting on a rapid time scale. 8. Flash sensitivity fell with increasing intensities of background light according to Weber's law. Sensitivity was reduced twofold by lights evoking about 120 photoisomerizations per second. Background lights decreased the time to peak and the integration time of the flash response by up to 20%.

  16. VISUAL ADAPTATION AND CHEMISTRY OF THE RODS

    PubMed Central

    Wald, George; Clark, Anna-Betty

    1937-01-01

    1. The reality of a chemical cycle proposed to describe the rhodopsin system is tested with dark adaptation measurements. 2. The first few minutes of rod dark adaptation are rapid following short, slower following long irradiation. As dark adaptation proceeds, the slow process grows more prominent, and occupies completely the final stages of adaptation. 3. Light adaptation displays similar duality. As the exposure to light of constant intensity lengthens, the visual threshold rises, and independently the speed of dark adaptation decreases. 4. These results conform with predictions from the chemical equations. PMID:19873041

  17. Nonequilibrium clustering of self-propelled rods.

    PubMed

    Peruani, Fernando; Deutsch, Andreas; Bär, Markus

    2006-09-01

    Motivated by aggregation phenomena in gliding bacteria, we study collective motion in a two-dimensional model of active, self-propelled rods interacting through volume exclusion. In simulations with individual particles, we find that particle clustering is facilitated by a sufficiently large packing fraction eta or length-to-width ratio kappa . The transition to clustering in simulations is well captured by a mean-field model for the cluster size distribution, which predicts that the transition values kappac of the aspect ratio for a fixed packing fraction eta are given by kappac=Ceta-1 where C is a constant.

  18. Nonelastomeric Rod Seals for Advanced Hydraulic Systems

    NASA Technical Reports Server (NTRS)

    Hady, W. F.; Waterman, A. W.

    1976-01-01

    Advanced high temperature hydraulic system rod sealing requirements can be met by using seals made of nonelastomeric (plastic) materials in applications where elastomers do not have adequate life. Exploratory seal designs were optimized for advanced applications using machinable polyimide materials. These seals demonstrated equivalent flight hour lives of 12,500 at 350 F and 9,875 at 400 F in advanced hydraulic system simulation. Successful operation was also attained under simulated space shuttle applications; 96 reentry thermal cycles and 1,438 hours of vacuum storage. Tests of less expensive molded plastic seals indicated a need for improved materials to provide equivalent performance to the machined seals.

  19. Gas Interference in Sucker Rod Pump

    NASA Astrophysics Data System (ADS)

    Samad, Abdus

    2010-10-01

    Commonly used artificial lift or dewatering system is sucker rod pump and gas interference of the pump is the biggest issue in the oil and gas industry. Gas lock or fluid pound problems occur due to the gas interference when the pump has partially or completely unfilled plunger barrel. There are several techniques available in the form of patents to solve these problems but those techniques have positive as well as negative aspects. Some of the designs rely on the leakage and some of the designs rely on the mechanical arrangements etc to break the gas lock. The present article compares the existing gas interference handling techniques.

  20. ALLOY COMPOSITION FOR NEUTRONIC REACTOR CONTROL RODS

    DOEpatents

    Lustman, B.; Losco, E.F.; Snyder, H.J.; Eggleston, R.R.

    1963-01-22

    This invention relates to alloy compositons suitable as cortrol rod material consisting of, by weight, from 85% to 85% Ag, from 2% to 20% In, from up to 10% of Cd, from up to 5% Sn, and from up to 1.5% Al, the amount of each element employed being determined by the equation X + 2Y + 3Z + 3W + 4V = 1.4 and less, where X, Y, Z, W, and V represent the atom fractions of the elements Ag, Cd, In, Al and Sn. (AEC)

  1. High-yield production of hydrophobins RodA and RodB from Aspergillus fumigatus in Pichia pastoris.

    PubMed

    Pedersen, Mona Højgaard; Borodina, Irina; Moresco, Jacob Lange; Svendsen, Winnie Edith; Frisvad, Jens Christian; Søndergaard, Ib

    2011-06-01

    Hydrophobins are small fungal proteins with amphipatic properties and the ability to self-assemble on a hydrophobic/hydrophilic interface; thus, many technical applications for hydrophobins have been suggested. The pathogenic fungus Aspergillus fumigatus expresses the hydrophobins RodA and RodB on the surface of its conidia. RodA is known to be of importance to the pathogenesis of the fungus, while the biological role of RodB is currently unknown. Here, we report the successful expression of both hydrophobins in Pichia pastoris and present fed-batch fermentation yields of 200-300 mg/l fermentation broth. Protein bands of expected sizes were detected by SDS-PAGE and western blotting, and the identity was further confirmed by tandem mass spectrometry. Both proteins were purified using his-affinity chromatography, and the high level of purity was verified by silver-stained SDS-PAGE. Recombinant RodA as well as rRodB were able to convert a glass surface from hydrophilic to hydrophobic similar to native RodA, but only rRodB was able to decrease the hydrophobicity of a Teflon-like surface to the same extent as native RodA, while rRodA showed this ability to a lesser extent. Recombinant RodA and native RodA showed a similar ability to emulsify air in water, while recombinant RodB could also emulsify oil in water better than the control protein bovine serum albumin (BSA). This is to our knowledge the first successful expression of hydrophobins from A. fumigatus in a eukaryote host, which makes it possible to further characterize both hydrophobins. Furthermore, the expression strategy and fed-batch production using P. pastoris may be transferred to hydrophobins from other species.

  2. Stirring with ghost rods in a lid-driven cavity

    NASA Astrophysics Data System (ADS)

    Kumar, Pankaj; Chen, Jie; Stremler, Mark

    2009-11-01

    It has shown that passive fluid particles moving on periodic orbits can be used to `stir' a viscous fluid in a two-dimensional lid-driven cavity that exhibits a figure-eight flow pattern (Stremler & Chen 2007). Fluid motion in the vicinity of these particles produces ``ghost rod'' structures that behave like semi-permeable rods in the flow. Since these ghost rods are present due to the system dynamics, perturbations in the boundary conditions lead to variations in the existence and structure of the ghost rods. We discuss these variations and assess the role of ghost rods in mixing over a range of operating conditions for this system. The results suggest that ghost rods can play an important role in mixing for other counter-rotating flows.

  3. Convergent synthesis of multiporphyrin light-harvesting rods

    DOEpatents

    Lindsey, Jonathan S.; Loewe, Robert S.

    2003-08-05

    The present invention provides a convergent method for the synthesis of light harvesting rods. The rods are oligomers of the formula A.sup.1 (A.sup.b+1).sub.b, wherein b is at least 1, A.sup.1 through A.sup.b+1 are covalently coupled rod segments, and each rod segment A.sup.1 through A.sup.1+b comprises a compound of the formula X.sup.1 (X.sup.m+1).sub.m wherein m is at least 1 and X.sup.1 through X.sup.m+1 are covalently coupled porphyrinic macrocycles. Light harvesting arrays and solar cells containing such light harvesting rods are also described, along with intermediates useful in such methods and rods produced by such methods.

  4. Dynamic, multiaxial impact response of confined and unconfined ceramic rods

    SciTech Connect

    Wise, J.L.; Grady, D.E.

    1993-09-01

    A new configuration for impact testing was implemented which yielded time-resolved measurements of the dynamic response of materials undergoing multiaxial strain. With this`-Method, one end of an initially stationary rod (ie., right circular cylinder) of test material was subjected to planar impact with a flat-faced projectile. The test rod was either free (unconfined) or mounted within a close-fitting sleeve which provided lateral confinement. Velocity interferometer diagnostics monitored the axial (longitudinal) velocity of the rod free end, and the transverse (radial) velocity for one or more points on the periphery of the rod or confinement sleeve. Analysis of the resultant velocity records allowed assessment of material properties, such as wave speeds and compressive yield strength, without the requirement of intact recovery of the rod. Data were obtained for alumina (Coors AD-99.5) rods in a series of tests involving variations in confinement and peak impact stress.

  5. Swarming and swirling in self-propelled polar granular rods

    NASA Astrophysics Data System (ADS)

    Kudrolli, Arshad; Lumay, Geoffroy; Volfson, Dmitri; Tsimring, Lev

    2008-03-01

    We discuss the dynamics of ``self-propelled" polar rods experimentally and numerically. In the experiment, the polar motion was achieved by vibrating rods with asymmetric mass distribution. In the numerics, we postulate a driving force acting along the axis of the rod. We observe aggregation of rods at the boundaries because of the inability of rods to turn around and escape for high enough density under low noise conditions. As vibration strength and thus noise is increased, the aggregation reduces and a uniformly distributed state displaying local orientation order and swirls are observed. We observe greater than √n density fluctuations which are in a qualitative agreement with the Toner-Tu model, but this agreement should not be over-emphasized since the model is directly applicable to a nematic regime. Our findings elucidate an important and interesting interplay between the shape and the directed motion in realistic self-propelled rods which affects the phenomenology of their collective dynamics.

  6. Monolayers of hard rods on planar substrates. I. Equilibrium.

    PubMed

    Oettel, M; Klopotek, M; Dixit, M; Empting, E; Schilling, T; Hansen-Goos, H

    2016-08-21

    The equilibrium properties of hard rod monolayers are investigated in a lattice model (where position and orientation of a rod are restricted to discrete values) as well as in an off-lattice model featuring spherocylinders with continuous positional and orientational degrees of freedom. Both models are treated using density functional theory and Monte Carlo simulations. Upon increasing the density of rods in the monolayer, there is a continuous ordering of the rods along the monolayer normal ("standing up" transition). The continuous transition also persists in the case of an external potential which favors flat-lying rods in the monolayer. This behavior is found in both the lattice and the continuum models. For the lattice model, we find very good agreement between the results from the specific DFT used (lattice fundamental measure theory) and simulations. The properties of lattice fundamental measure theory are further illustrated by the phase diagrams of bulk hard rods in two and three dimensions.

  7. Monolayers of hard rods on planar substrates. I. Equilibrium

    NASA Astrophysics Data System (ADS)

    Oettel, M.; Klopotek, M.; Dixit, M.; Empting, E.; Schilling, T.; Hansen-Goos, H.

    2016-08-01

    The equilibrium properties of hard rod monolayers are investigated in a lattice model (where position and orientation of a rod are restricted to discrete values) as well as in an off-lattice model featuring spherocylinders with continuous positional and orientational degrees of freedom. Both models are treated using density functional theory and Monte Carlo simulations. Upon increasing the density of rods in the monolayer, there is a continuous ordering of the rods along the monolayer normal ("standing up" transition). The continuous transition also persists in the case of an external potential which favors flat-lying rods in the monolayer. This behavior is found in both the lattice and the continuum models. For the lattice model, we find very good agreement between the results from the specific DFT used (lattice fundamental measure theory) and simulations. The properties of lattice fundamental measure theory are further illustrated by the phase diagrams of bulk hard rods in two and three dimensions.

  8. Digital Alloy Absorber for Photodetectors

    NASA Technical Reports Server (NTRS)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

    2016-01-01

    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

  9. Safety analysis forseismic motion of control rods accounting for rod misalignment

    SciTech Connect

    Osmin, W.L.; Paik, I.K.

    1992-01-01

    The purpose of this report is to provide a summary of the results of three safety analyses performed by the SRL Safety Analysis Group (SAG) to assess the safety impact of control rod motion induced by a Design Basis Earthquake (DBE).

  10. Laser decontamination of the radioactive lightning rods

    NASA Astrophysics Data System (ADS)

    Potiens, A. J.; Dellamano, J. C.; Vicente, R.; Raele, M. P.; Wetter, N. U.; Landulfo, E.

    2014-02-01

    Between 1970 and 1980 Brazil experienced a significant market for radioactive lightning rods (RLR). The device consists of an air terminal with one or more sources of americium-241 attached to it. The sources were used to ionize the air around them and to increase the attraction of atmospheric discharges. Because of their ineffectiveness, the nuclear regulatory authority in Brazil suspended the license for manufacturing, commerce and installation of RLR in 1989, and determined that the replaced RLR were to be collected to a centralized radioactive waste management facility for treatment. The first step for RLR treatment is to remove the radioactive sources. Though they can be easily removed, some contaminations are found all over the remaining metal scrap that must decontaminated for release, otherwise it must be treated as radioactive waste. Decontamination using various chemicals has proven to be inefficient and generates large amounts of secondary wastes. This work shows the preliminary results of the decontamination of 241Am-contaminated metal scrap generated in the treatment of radioactive lightning rods applying laser ablation. A Nd:YAG nanoseconds laser was used with 300 mJ energy leaving only a small amount of secondary waste to be treated.

  11. Condensation transition in polydisperse hard rods.

    PubMed

    Evans, M R; Majumdar, S N; Pagonabarraga, I; Trizac, E

    2010-01-07

    We study a mass transport model, where spherical particles diffusing on a ring can stochastically exchange volume v, with the constraint of a fixed total volume V= sum(i=1) (N)v(i), N being the total number of particles. The particles, referred to as p-spheres, have a linear size that behaves as v(i) (1/p) and our model thus represents a gas of polydisperse hard rods with variable diameters v(i) (1/p). We show that our model admits a factorized steady state distribution which provides the size distribution that minimizes the free energy of a polydisperse hard-rod system, under the constraints of fixed N and V. Complementary approaches (explicit construction of the steady state distribution on the one hand; density functional theory on the other hand) completely and consistently specify the behavior of the system. A real space condensation transition is shown to take place for p>1; beyond a critical density a macroscopic aggregate is formed and coexists with a critical fluid phase. Our work establishes the bridge between stochastic mass transport approaches and the optimal polydispersity of hard sphere fluids studied in previous articles.

  12. An elastic rod model for anguilliform swimming.

    PubMed

    McMillen, T; Holmes, P

    2006-11-01

    We develop a model for anguilliform (eel-like) swimming as an elastic rod actuated via time-dependent intrinsic curvature and subject to hydrodynamic drag forces, the latter as proposed by Taylor (in Proc Roy Proc Lond A 214:158-183, 1952). We employ a eometrically exact theory and discretize the resulting nonlinear partial differential evolution both to perform numerical simulations, and to compare with previous models consisting of chains of rigid links or masses connected by springs, dampers, and prescribed force generators representing muscles. We show that muscle activations driven by motoneuronal spike trains via calcium dynamics produce intrinsic curvatures corresponding to near-sinusoidal body shapes in longitudinally-uniform rods, but that passive elasticity causes Taylor's assumption of prescribed shape to fail, leading to time-periodic motions and lower speeds than those predicted Taylor (in Proc Roy Proc Lond A 214:158-183, 1952). We investigate the effects of bending stiffness, body geometry, and activation patterns on swimming speed, turning behavior, and acceleration to steady swimming. We show that laterally-uniform activation yields stable straight swimming and laterally differential activation levels lead to stable turns, and we argue that tapered bodies with reduced caudal (tail-end) activation (to produce uniform intrinsic curvature) swim faster than ones with uniform activation.

  13. Fluid Dynamics in Sucker Rod Pumps

    SciTech Connect

    Cutler, Robert P.; Mansure, Arthur J.

    1999-06-01

    Sucker rod pumps are installed in approximately 90% of all oil wells in the U.S. Although they have been widely used for decades, there are many issues regarding the fluid dynamics of the pump that have not been filly investigated. A project was conducted at Sandia National Laboratories to develop an improved understanding of the fluid dynamics inside a sucker rod pump. A mathematical flow model was developed to predict pressures in any pump component or an entire pump under single-phase fluid and pumping conditions. Laboratory flow tests were conducted on instrumented individual pump components and on a complete pump to verifi and refine the model. The mathematical model was then converted to a Visual Basic program to allow easy input of fluid, geometry and pump parameters and to generate output plots. Examples of issues affecting pump performance investigated with the model include the effects of viscosity, surface roughness, valve design details, plunger and valve pressure differentials, and pumping rate.

  14. Application of polyimide actuator rod seals

    NASA Technical Reports Server (NTRS)

    Watermann, A. W.; Gay, B. F.; Robinson, E. D.; Srinath, S. K.; Nelson, W. G.

    1972-01-01

    Development of polyimide two-stage hydraulic actuator rod seals for application in high-performance aircraft was accomplished. The significant portion of the effort was concentrated on optimization of the chevron and K-section second-stage seal geometries to satisfy the requirements for operation at 450 K (350 F) with dynamic pressure loads varying between 200 psig steady-state and 1500 psig impulse cycling. Particular significance was placed on reducing seal gland dimension by efficiently utilizing the fatigue allowables of polyimide materials. Other objectives included investigation of pressure balancing techniques for first-stage polyimide rod seals for 4000 psig 450 K(350 F) environment and fabrication of a modular retainer for the two-stage combination. Seals were fabricated in 0.0254 m (1.0in.) and 0.0635 m (2.5in.) sizes and tested for structural integrity, frictional resistance, and endurance life. Test results showed that carefully designed second stages using polyimides could be made to satisfy the dynamic return pressure requirements of applications in high-performance aircraft. High wear under full system pressure indicated that further research is necessary to obtain an acceptable first-stage design. The modular retainer was successfully tested and showed potential for new actuator applications.

  15. The evaluation of corrosion resistant rod end rolling element bearings

    SciTech Connect

    Braza, J.F.; Giuntoli, K.; Imundo, J.R.

    1998-12-31

    Recent developments on carburizing grades of stainless steels have provided new materials to produce corrosion resistant airframe control bearings. This paper presents the application of one of these new carburizing grades of stainless steel to rod end ball bearings. The outer ring of the rod end bearing is made out of carburized stainless steel, while the inner ring and balls are made out of through-hardened stainless steel. The stainless steel rod end bearings were evaluated according to various ASTM and Military specifications for performance and corrosion resistance. The stainless steel rod end bearings exceeded the performance requirements of standard rod end bearings (which are comprised of a carburized 8620 steel outer ring and 52100 steel inner ring and balls) in accordance with MIL-B-6039. The rod end bearings were evaluated in the radial fracture load, axial fracture load, and radial dynamic load tests. Also, salt spray and alternate immersion corrosion tests (ASTM B 117-85 and G 44-88, respectively) were conducted on the stainless steel rod end bearings. The stainless steel rod end bearings exhibited superior corrosion resistance to the standard 8620/52100 steel rod end bearings.

  16. Pultruded Rod/Overwrap Testing for Various Stitched Stringer Configurations

    NASA Technical Reports Server (NTRS)

    Leone, Frank A., Jr.

    2016-01-01

    The unidirectional carbon pultruded rod running through the tops of the stringers is a key design feature of the Pultruded Rod Efficient Unitized Structure (PRSEUS) concept as applied to aircraft fuselage structure. Reported herein are the test methods and results from a test campaign in which the strength of the rod/overwrap interface of various PRSEUS stringer configurations were characterized. The different stringer configurations included different materials and stacking sequences for the stringer overwrap and whether or not an additional layer of adhesive was included between the rod and the overwrap.

  17. Biophysical mechanism of transient retinal phototropism in rod photoreceptors

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Gai, Shaoyan; Yao, Xincheng

    2016-03-01

    Oblique light stimulation evoked transient retinal phototropism (TRP) has been recently detected in frog and mouse retinas. High resolution microscopy of freshly isolated retinas indicated that the TRP is predominated by rod photoreceptors. Comparative confocal microscopy and optical coherence tomography (OCT) revealed that the TRP predominantly occurred from the photoreceptor outer segment (OS). However, biophysical mechanism of rod OS change is still unknown. In this study, frog retinal slices, which open a cross section of retinal photoreceptor and other functional layers, were used to test the effect of light stimulation on rod OS. Near infrared light microscopy was employed to monitor photoreceptor changes in retinal slices stimulated by a rectangular-shaped visible light flash. Rapid rod OS length change was observed after the stimulation delivery. The magnitude and direction of the rod OS change varied with the position of the rods within the stimulated area. In the center of stimulated region the length of the rod OS shrunk, while in the peripheral region the rod OS tip swung towards center region in the plane perpendicular to the incident stimulus light. Our experimental result and theoretical analysis suggest that the observed TRP may reflect unbalanced disc-shape change due to localized pigment bleaching. Further investigation is required to understand biochemical mechanism of the observed rod OS kinetics. Better study of the TRP may provide a noninvasive biomarker to enable early detection of age-related macular degeneration (AMD) and other diseases that are known to produce retinal photoreceptor dysfunctions.

  18. Transient elastic impact response of slender graphite rods

    SciTech Connect

    Erdem, I.

    2007-12-15

    Graphite rods are manufactured by extruding the mixture of calcined petroleum coke and coal tar pitch into the desired shape and baking the cooled specimens at about 800{sup o}C. Cracking can occur in rods during the manufacturing process. It is useful to be able to detect the presence of such cracks in the rods prior to their being machined and put into use as electrodes or cathodes or thermal insulator. In an effort to develop a nondestructive testing approach to evaluation of the rods, transient elastic impact was determined for slender rods. Theory for solid, slender rods provided an important starting point for this work. Subsequently, numerical models were developed and simulation was used to determine the response of rods containing cracks. Experiments on graphite rods with and without cracks were conducted and the internal condition determined from the recorded signals. The rods were then cut lengthwise to reveal the internal condition and verify the predicted results. In all cases the knowledge gained from simulation allowed for the presence of cracks to be detected.

  19. Synthesis and Optical Properties of Lead-Free Cesium Tin Halide Perovskite Quantum Rods with High-Performance Solar Cell Application.

    PubMed

    Chen, Lin-Jer; Lee, Chia-Rong; Chuang, Yu-Ju; Wu, Zhao-Han; Chen, Chienyi

    2016-12-15

    Herein, the fabrication of a lead-free cesium tin halide perovskite produced via a simple solvothermal process is reported for the first time. The resulting CsSnX3 (X = Cl, Br, and I) quantum rods show composition-tunable photoluminescence (PL) emissions over the entire visible spectral window (from 625 to 709 nm), as well as significant tunability of the optical properties. In this study, we demonstrate that through hybrid materials (CsSnX3) with different halides, the system can be tunable in terms of PL. By replacing the halide of the CsSnX3 quantum rods, a power conversion efficiency of 12.96% under AM 1.5 G has been achieved. This lead-free quantum rod replacement has demonstrated to be an effective method to create an absorber layer that increases light harvesting and charge collection for photovoltaic applications in its perovskite phase.

  20. Densely packed aluminum-silver nanohelices as an ultra-thin perfect light absorber

    PubMed Central

    Jen, Yi-Jun; Huang, Yu-Jie; Liu, Wei-Chih; Lin, Yueh Weng

    2017-01-01

    Metals have been formed into nanostructures to absorb light with high efficiency through surface plasmon resonances. An ultra-thin plasmonic structure that exhibits strong absorption over wide ranges of wavelengths and angles of incidence is sought. In this work, a nearly perfect plasmonic nanostructure is fabricated using glancing angle deposition. The difference between the morphologies of obliquely deposited aluminum and silver nanohelices is exploited to form a novel three-dimensional structure, which is an aluminum-silver nanohelix array on a pattern-free substrate. With a thickness of only 470 nm, densely distributed nanohelices support rod-to-rod localized surface plasmons for broadband and polarization-independent light extinction. The extinctance remains high over wavelengths from 400 nm to 2000 nm and angles of incidence from 0° to 70°. PMID:28045135

  1. Densely packed aluminum-silver nanohelices as an ultra-thin perfect light absorber

    NASA Astrophysics Data System (ADS)

    Jen, Yi-Jun; Huang, Yu-Jie; Liu, Wei-Chih; Lin, Yueh Weng

    2017-01-01

    Metals have been formed into nanostructures to absorb light with high efficiency through surface plasmon resonances. An ultra-thin plasmonic structure that exhibits strong absorption over wide ranges of wavelengths and angles of incidence is sought. In this work, a nearly perfect plasmonic nanostructure is fabricated using glancing angle deposition. The difference between the morphologies of obliquely deposited aluminum and silver nanohelices is exploited to form a novel three-dimensional structure, which is an aluminum-silver nanohelix array on a pattern-free substrate. With a thickness of only 470 nm, densely distributed nanohelices support rod-to-rod localized surface plasmons for broadband and polarization-independent light extinction. The extinctance remains high over wavelengths from 400 nm to 2000 nm and angles of incidence from 0° to 70°.

  2. Shock absorber operates over wide range

    NASA Technical Reports Server (NTRS)

    Creasy, W. K.; Jones, J. C.

    1965-01-01

    Piston-type hydraulic shock absorber, with a metered damping system, operates over a wide range of kinetic energy loading rates. It is used for absorbing shock and vibration on mounted machinery and heavy earth-moving equipment.

  3. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... absorber is a device made of paper or cotton intended to absorb moisture from the oral cavity during dental... manufacturing practice requirements of the quality system regulation in part 820 of this chapter, with...

  4. Improving the laboratory monitoring of absorbent oil

    SciTech Connect

    V.S. Shved; S.S. Sychev; I.V. Safina; S.A. Klykov

    2009-05-15

    The performance of absorbent coal tar oil is analyzed as a function of the constituent and group composition. The qualitative and quantitative composition of the oil that ensures the required absorbent properties is determined. Operative monitoring may be based on absorbent characteristics that permit regulation of the beginning and end of regeneration.

  5. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, Daniel C.

    1990-02-06

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  6. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, D.C.

    1987-11-20

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compound of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved. 2 figs.

  7. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, Daniel C.

    1990-01-01

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  8. Biomolecular rods and tubes in nanotechnology

    NASA Astrophysics Data System (ADS)

    Bittner, Alexander M.

    2005-02-01

    Biomolecules are vitally important elements in nanoscale science and also in future nanotechnology. Their shape and their chemical and physical functionality can give them a big advantage over inorganic and organic substances. While this becomes most obvious in proteins and peptides, with their complicated, but easily controlled chemistry, other biomolecular substances such as DNA, lipids and carbohydrates can also be important. In this review, the emphasis is on one-dimensional molecules and on molecules that self-assemble into linear structures, and on their potential applications. An important aspect is that biomolecules can act as templates, i.e. their shape and chemical properties can be employed to arrange inorganic substances such as metals or metal compounds on the nanometre scale. In particular, rod- and tube-like nanostructures can show physical properties that are different from those of the bulk material, and thus these structures are likely to be a basis for new technology.

  9. Biomolecular rods and tubes in nanotechnology.

    PubMed

    Bittner, Alexander M

    2005-02-01

    Biomolecules are vitally important elements in nanoscale science and also in future nanotechnology. Their shape and their chemical and physical functionality can give them a big advantage over inorganic and organic substances. While this becomes most obvious in proteins and peptides, with their complicated, but easily controlled chemistry, other biomolecular substances such as DNA, lipids and carbohydrates can also be important. In this review, the emphasis is on one-dimensional molecules and on molecules that self-assemble into linear structures, and on their potential applications. An important aspect is that biomolecules can act as templates, i.e. their shape and chemical properties can be employed to arrange inorganic substances -- such as metals or metal compounds -- on the nanometre scale. In particular, rod- and tube-like nanostructures can show physical properties that are different from those of the bulk material, and thus these structures are likely to be a basis for new technology.

  10. Trapping and sorting active granular rods

    NASA Astrophysics Data System (ADS)

    Ramaswamy, Sriram; Kumar, Nitin; Soni, Harsh; Gupta, Rahul; Sood, Ajay

    We report experiments and simulations on collective trapping in a horizontal monolayer of tapered granular rods rendered motile by mechanical vibration. A macroscopic fraction of the particles are trapped by a V-shaped obstacle if its opening angle is less than a threshold value of about 120 degrees, consistent with active Brownian simulations [PRL 108, 268307 (2012)]. the transition between trapped and untrapped states becomes sharper with increasing system size in our numerical studies. We offer a theoretical understanding of this nonequilibrium phase transition based on collective noise suppression and an analysis of fluxes. We show also that the trap can serve to separate particles based on their motility and rotational diffusivity. On leave from Dept of Physics, Indian Institute of Science.

  11. Electric Fuel Rod Simulator Fabrication at ORNL

    SciTech Connect

    Ott, Larry J.; McCulloch, Reg

    2004-02-04

    Commercial vendors could not supply the high-quality, highly instrumented electric fuel rod simulators (FRS) required for large thermal-hydraulic safety-oriented experiments at the Oak Ridge National Laboratory (ORNL) in the 1970s and early 1980s. Staff at ORNL designed, developed, and manufactured the simulators utilized in these safety experiments. Important FRS design requirements include (1) materials of construction, (2) test power requirements and availability, (3) experimental test objectives, (4) supporting thermal analyses, and (5) extensive quality control throughout all phases of FRS fabrication. This paper will present an overview of these requirements (design, analytics, and quality control) as practiced at ORNL to produce a durable high-quality FRS.

  12. Carbon dioxide absorbents for rebreather diving.

    PubMed

    Pennefather, John

    2016-09-01

    Firstly I would like to thank SPUMS members for making me a Life Member of SPUMS; I was surprised and greatly honoured by the award. I also want to confirm and expand on the findings on carbon dioxide absorbents reported by David Harvey et al. For about 35 years, I was the main player in deciding which absorbent went into Australian Navy and Army diving sets. On several occasions, suppliers of absorbents to the anaesthesia market tried to supply the Australian military market. On no occasion did they provide absorbent that came close to the minimum absorbent capacity required, generally being 30-40% less efficient than diving-grade absorbents. Because I regard lives as being more important than any likely dollar saving, the best absorbent was always selected unless two suppliers provided samples with the same absorbent capacity. On almost every occasion, there was a clear winner and cost was never considered. I suggest the same argument for the best absorbent should be used by members and their friends who dive using rebreather sets. I make this point because of my findings on a set that was brought to me after the death of its owner. The absorbent was not the type or grain size recommended by the manufacturer of the set and did not resemble any of the diving grade absorbents I knew of. I suspected by its appearance that it was anaesthetic grade absorbent. When I tested the set, the absorbent system failed very quickly so it is likely that carbon dioxide toxicity contributed to his death. The death was not the subject of an inquest and I have no knowledge of how the man obtained the absorbent. Possibly there was someone from an operating theatre staff who unintentionally caused their friend's death by supplying him with 'borrowed absorbent'. I make this point as I would like to discourage members from making a similar error.

  13. Packed rod neutron shield for fast nuclear reactors

    DOEpatents

    Eck, John E.; Kasberg, Alvin H.

    1978-01-01

    A fast neutron nuclear reactor including a core and a plurality of vertically oriented neutron shield assemblies surrounding the core. Each assembly includes closely packed cylindrical rods within a polygonal metallic duct. The shield assemblies are less susceptible to thermal stresses and are less massive than solid shield assemblies, and are cooled by liquid coolant flow through interstices among the rods and duct.

  14. CONTROL ROD FOR A NUCLEAR REACTOR AND METHOD OF PREPARATION

    DOEpatents

    Hausner, H.H.

    1958-12-30

    BS>An improved control rod is presented for a nuclear reactor. This control rod is comprised of a rare earth metal oxide or rare earth metal carbide such as gadolinium oxide or gadolinium carbide, uniformly distributed in a metal matrix having a low cross sectional area of absorption for thermal neutrons, such as aluminum, beryllium, and zirconium.

  15. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rod, up-and-down. 236.794 Section 236.794 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., up-and-down. A rod used for connecting the semaphore arm to the operating mechanism of a signal....

  16. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rod, up-and-down. 236.794 Section 236.794 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., up-and-down. A rod used for connecting the semaphore arm to the operating mechanism of a signal....

  17. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rod, up-and-down. 236.794 Section 236.794 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., up-and-down. A rod used for connecting the semaphore arm to the operating mechanism of a signal....

  18. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Rod, up-and-down. 236.794 Section 236.794 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., up-and-down. A rod used for connecting the semaphore arm to the operating mechanism of a signal....

  19. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rod, up-and-down. 236.794 Section 236.794 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION..., up-and-down. A rod used for connecting the semaphore arm to the operating mechanism of a signal....

  20. Strategy Access Rods: A Hands-On Approach.

    ERIC Educational Resources Information Center

    Worthing, Bernadette; Laster, Barbara

    2002-01-01

    Describes Strategy Access Rods (SARs), balsa-wood, prism-like or rectangular rods on which a one-sentence reading strategy phrase in the first person is printed. Notes SARs serve as a visual, auditory, kinesthetic, and tactile reminder of the strategies available to developing readers. Discusses use of SARs for word recognition and comprehension.…

  1. Switch isotropic/anisotropic wettability via dual-scale rods

    NASA Astrophysics Data System (ADS)

    He, Yang; Jiang, Chengyu; Wang, Shengkun; Ma, Zhibo; Yuan, Weizheng

    2014-10-01

    It is the first time to demonstrate the comparison of isotropic/anisotropic wettability between dual-scale micro-nano-rods and single-scale micro-rods. Inspired by the natural structures of rice leaf, a series of micro-nano-rods and micro-rods with different geometric parameters were fabricated using micro-fabrication technology. Experimental measured apparent contact angles and advancing and receding contact angles from orthogonal orientations were characterized. The difference of contact angles from orthogonal orientation on dual-scale rods was much smaller than those on single-scale rods in both static and dynamic situation. It indicated that the dual-scale micro-nano-rods showed isotropic wettability, while single-scale micro-rods showed anisotropic wettability. The switch of isotropic/anisotropic wettability could be illustrated by different wetting state and contact line moving. It offers a facial way to switch isotropic/anisotropic wettability of the surface via dual-scale or single-scale structure.

  2. Approximation in LQG control of a thermoelastic rod

    NASA Technical Reports Server (NTRS)

    Gibson, J. S.; Rosen, I. G.; Tao, G.

    1989-01-01

    Control and estimator gains are computed for linear-quadratic-Gaussian (LQG) optimal control of the axial vibrations of a thermoelastic rod. The computations are based on a modal approximation of the partial differential equations representing the rod, and convergence of the approximations to control and estimator gains is the main issue.

  3. 32 CFR 989.21 - Record of decision (ROD).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Record of decision (ROD). 989.21 Section 989.21 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.21 Record of decision (ROD). (a) The proponent and the...

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Rod vision is controlled by dopamine-dependent sensitization of rod bipolar cells by GABA.

    PubMed

    Herrmann, Rolf; Heflin, Stephanie J; Hammond, Timothy; Lee, Bowa; Wang, Jing; Gainetdinov, Raul R; Caron, Marc G; Eggers, Erika D; Frishman, Laura J; McCall, Maureen A; Arshavsky, Vadim Y

    2011-10-06

    Dark and light adaptation of retinal neurons allow our vision to operate over an enormous light intensity range. Here we report a mechanism that controls the light sensitivity and operational range of rod-driven bipolar cells that mediate dim-light vision. Our data indicate that the light responses of these cells are enhanced by sustained chloride currents via GABA(C) receptor channels. This sensitizing GABAergic input is controlled by dopamine D1 receptors, with horizontal cells serving as a plausible source of GABA release. Our findings expand the role of dopamine in vision from its well-established function of suppressing rod-driven signals in bright light to enhancing the same signals under dim illumination. They further reveal a role for GABA in sensitizing the circuitry for dim-light vision, thereby complementing GABA's traditional role in providing dynamic feedforward and feedback inhibition in the retina.

  6. A polarization-independent broadband terahertz absorber

    SciTech Connect

    Shi, Cheng; Zang, XiaoFei E-mail: ymzhu@usst.edu.cn; Wang, YiQiao; Chen, Lin; Cai, Bin; Zhu, YiMing E-mail: ymzhu@usst.edu.cn

    2014-07-21

    A highly efficient broadband terahertz absorber is designed, fabricated, and experimentally as well as theoretically evaluated. The absorber comprises a heavily doped silicon substrate and a well-designed two-dimensional grating. Due to the destructive interference of waves and diffraction, the absorber can achieve over 95% absorption in a broad frequency range from 1 to 2 THz and for angles of incidence from 0° to 60°. Such a terahertz absorber is also polarization-independent due to its symmetrical structure. This omnidirectional and broadband absorber have potential applications in anti-reflection coatings, imaging systems, and so on.

  7. Fatigue Life Improving of Drill Rod by Inclusion Control

    NASA Astrophysics Data System (ADS)

    Wang, Linzhu; Yang, Shufeng; Li, Jingshe; Liu, Wei; Zhou, Yinghao

    2016-08-01

    Large and hard inclusions often deteriorate the service performance and reduce the fatigue lifetime of drill rods. In this paper, the main reasons of the rupture of drill rods were analyzed by the examination of their fracture and it is found that the large inclusions were the main reason of breakage of rod drill. The inclusions were high of Ca content or Al2O3 rich. Smaller and better deformability inclusions were obtained by the optimization of refining slag, calcium treatment process and the flow control devices of tundish. Results of industrial experiment after optimization show that total oxygen content of drill rods decreased by more than 50%, macro-inclusions weight fraction decreased from about 4 mg/10 kg to about 0.3 mg/10 kg and the micro-inclusions average size decreased from 6 to 3.6 μm. The average using times of drill rods after optimization were increased by about 60%.

  8. Semiconductor Quantum Rods as Single Molecule FluorescentBiological Labels

    SciTech Connect

    Fu, Aihua; Gu, Weiwei; Boussert, Benjamine; Koski, Kristie; Gerion, Daniele; Manna, Liberato; Le Gros, Mark; Larabell, Carolyn; Alivisatos, A. Paul

    2006-05-29

    In recent years, semiconductor quantum dots have beenapplied with great advantage in a wide range of biological imagingapplications. The continuing developments in the synthesis of nanoscalematerials and specifically in the area of colloidal semiconductornanocrystals have created an opportunity to generate a next generation ofbiological labels with complementary or in some cases enhanced propertiescompared to colloidal quantum dots. In this paper, we report thedevelopment of rod shaped semiconductor nanocrystals (quantum rods) asnew fluorescent biological labels. We have engineered biocompatiblequantum rods by surface silanization and have applied them fornon-specific cell tracking as well as specific cellular targeting. Theproperties of quantum rods as demonstrated here are enhanced sensitivityand greater resistance for degradation as compared to quantum dots.Quantum rods have many potential applications as biological labels insituations where their properties offer advantages over quantumdots.

  9. Simplified modeling of the EBR-II control rods

    SciTech Connect

    Angelo, P.L.

    1995-06-25

    Simplified models of EBR-II control and safety rods have been developed for core modeling under various operational and shutdown conditions. A parametric study was performed on normal worth, high worth, and safety rod type control rods. A summary of worth changes due to individual modeling approximations is tabulated. Worth effects due to structural modeling simplification are negligible. Fuel region homogenization and burnup compression contributes more than any other factor. Reference case C/E values (ratio of calculated worth from detailed model to measured worth) of 1.072 and 1.142 for safety and normal worth rods indicate acceptable errors when the approximations are used. Fuel burnup effect illustrates rod worth sensitivity to the modeling approximation. Aggregate effects are calculated under a reduced mesh.

  10. Random geometric graph description of connectedness percolation in rod systems.

    PubMed

    Chatterjee, Avik P; Grimaldi, Claudio

    2015-09-01

    The problem of continuum percolation in dispersions of rods is reformulated in terms of weighted random geometric graphs. Nodes (or sites or vertices) in the graph represent spatial locations occupied by the centers of the rods. The probability that an edge (or link) connects any randomly selected pair of nodes depends upon the rod volume fraction as well as the distribution over their sizes and shapes, and also upon quantities that characterize their state of dispersion (such as the orientational distribution function). We employ the observation that contributions from closed loops of connected rods are negligible in the limit of large aspect ratios to obtain percolation thresholds that are fully equivalent to those calculated within the second-virial approximation of the connectedness Ornstein-Zernike equation. Our formulation can account for effects due to interactions between the rods, and many-body features can be partially addressed by suitable choices for the edge probabilities.

  11. Random geometric graph description of connectedness percolation in rod systems

    NASA Astrophysics Data System (ADS)

    Chatterjee, Avik P.; Grimaldi, Claudio

    2015-09-01

    The problem of continuum percolation in dispersions of rods is reformulated in terms of weighted random geometric graphs. Nodes (or sites or vertices) in the graph represent spatial locations occupied by the centers of the rods. The probability that an edge (or link) connects any randomly selected pair of nodes depends upon the rod volume fraction as well as the distribution over their sizes and shapes, and also upon quantities that characterize their state of dispersion (such as the orientational distribution function). We employ the observation that contributions from closed loops of connected rods are negligible in the limit of large aspect ratios to obtain percolation thresholds that are fully equivalent to those calculated within the second-virial approximation of the connectedness Ornstein-Zernike equation. Our formulation can account for effects due to interactions between the rods, and many-body features can be partially addressed by suitable choices for the edge probabilities.

  12. A Characterization of the Radiation from a Rod-Pinch

    NASA Astrophysics Data System (ADS)

    Swanekamp, S. B.; Allen, R. J.; Hinshelwood, D. D.; Mosher, D.; Schumer, J. W.; Young, F. C.

    2001-10-01

    The rod pinch diode is being developed as an intense, x-ray source for high-resolution flash radiography. Recent experiments on the Asterix pulsed-power generator at the CEG in France have demonstrated rod-pinch operation with 2-4 MV endpoint voltages and have demonstrated doses of = 5-23 rads-Si at 1 meter with a 1-mm diameter spot size. A series of = simulations with the Integrated Tiger Series (ITS) electron/photon transport code = were performed to characterize the radiation from a rod-pinch. The electron-energy and incident-angle distributions on the tungsten rod = were input to ITS from MAGIC PIC predictions. These simulations give = information about the angular dependence of the radiation from the rod-pinch and the axial extent of the radiation source. The results from these simulations will be compared with radiation measurements from Asterix.

  13. Behaviour of the rod network in the tiger salamander retina mediated by membrane properties of individual rods

    PubMed Central

    Attwell, David; Wilson, Martin

    1980-01-01

    1. The spread of electrical signals between rods in the salamander retina was examined by passing current into one rod and recording the voltage responses in nearby rods. Rod network behaviour, measured in this way, was simulated from data on rod membrane properties gathered in voltage-clamp experiments on single isolated rods. 2. The network voltage responses to square current pulses became smaller, more transient, and had a longer time-to-peak, for rods further away from the site of current injection. Depolarizing currents produced smaller responses than hyperpolarizing currents of the same magnitude. 3. Neighbouring rods and cones were coupled less strongly than neighbouring rods. 4. The response of the rod network to current injection was unaffected by 2 mm-aspartate-, which eliminates transmission from receptors to horizontal cells. 5. The input resistance of single isolated rods, measured at the resting potential, varied between 100 and 680 MΩ. The lower values were probably due to damage by the micro-electrodes. Electrical coupling was found to be very strong between the rod inner and outer segments. 6. A strong `instantaneous' outward rectification seen in isolated rods at potentials positive to -35 mV was reduced, but not abolished, by 15 mm-TEA. 7. In normal solution, isolated rods exhibited a voltage- and time-dependent current, IA, whose kinetics were approximated by a single first-order gating variable, and whose activation curve spanned the range between -40 and -80 mV. The time constant for the current varied with voltage and was 60-200 msec between -140 and -40 mV. 8. A reversal potential for IA could not be found between -140 and -40 mV in normal solution, and the fully activated current, ĪA, was approximately voltage-independent, with a magnitude of ∼ 0.1 nA over this potential range. 9. By several criteria, IA behaved as a single inward current activated by hyperpolarization. Pharmacological studies suggest, however, that it is the sum of at

  14. Fretting wear behaviors of a dual-cooled nuclear fuel rod under a simulated rod vibration

    SciTech Connect

    Lee, Young-Ho; Kim, Hyung-Kyu; Kang, Heung-Seok; Yoon, Kyung-Ho; Kim, Jae-Yong; Lee, Kang-Hee

    2012-06-06

    Recently, a dual-cooled fuel (i.e., annular fuel) that is compatible with current operating PWR plants has been proposed in order to realize both a considerable amount of power uprating and an increase of safety margins. As the design concept should be compatible with current operating PWR plants, however, it shows a narrow gap between the fuel rods when compared with current solid nuclear fuel arrays and needs to modify the spacer grid shapes and their positions. In this study, fretting wear tests have been performed to evaluate the wear resistance of a dual-cooled fuel by using a proposed spring and dimple of spacer grids that have a cantilever type and hemispherical shape, respectively. As a result, the wear volume of the spring specimen gradually increases as the contact condition is changed from a certain gap, just contact to positive force. However, in the dimple specimen, just contact condition shows a large wear volume. In addition, a circular rod motion at upper region of contact surface is gradually increased and its diametric size depends on the wear depth increase. Based on the test results, the fretting wear resistance of the proposed spring and dimple is analyzed by comparing the wear measurement results and rod motion in detail.

  15. Autophagy supports survival and phototransduction protein levels in rod photoreceptors

    PubMed Central

    Zhou, Z; Doggett, T A; Sene, A; Apte, R S; Ferguson, T A

    2015-01-01

    Damage and loss of the postmitotic photoreceptors is a leading cause of blindness in many diseases of the eye. Although the mechanisms of photoreceptor death have been extensively studied, few studies have addressed mechanisms that help sustain these non-replicating neurons for the life of an organism. Autophagy is an intracellular pathway where cytoplasmic constituents are delivered to the lysosomal pathway for degradation. It is not only a major pathway activated in response to cellular stress, but is also important for cytoplasmic turnover and to supply the structural and energy needs of cells. We examined the importance of autophagy in photoreceptors by deleting the essential autophagy gene Atg5 specifically in rods. Loss of autophagy led to progressive degeneration of rod photoreceptors beginning at 8 weeks of age such that by 44 weeks few rods remained. Cone photoreceptor numbers were only slightly diminished following rod degeneration but their function was significantly decreased. Rod cell death was apoptotic but was not dependent on daily light exposure or accelerated by intense light. Although the light-regulated translocation of the phototransduction proteins arrestin and transducin were unaffected in rods lacking autophagy, Atg5-deficient rods accumulated transducin-α as they degenerated suggesting autophagy might regulate the level of this protein. This was confirmed when the light-induced decrease in transducin was abolished in Atg5-deficient rods and the inhibition of autophagy in retinal explants cultures prevented its degradation. These results demonstrate that basal autophagy is essential to the long-term health of rod photoreceptors and a critical process for maintaining optimal levels of the phototransduction protein transducin-α. As the lack of autophagy is associated with retinal degeneration and altered phototransduction protein degradation in the absence of harmful gene products, this process may be a viable therapeutic target where rod

  16. Age-related deterioration of rod vision in mice.

    PubMed

    Kolesnikov, Alexander V; Fan, Jie; Crouch, Rosalie K; Kefalov, Vladimir J

    2010-08-18

    Even in healthy individuals, aging leads to deterioration in visual acuity, contrast sensitivity, visual field, and dark adaptation. Little is known about the neural mechanisms that drive the age-related changes of the retina and, more specifically, photoreceptors. According to one hypothesis, the age-related deterioration in rod function is due to the limited availability of 11-cis-retinal for rod pigment formation. To determine how aging affects rod photoreceptors and to test the retinoid-deficiency hypothesis, we compared the morphological and functional properties of rods of adult and aged B6D2F1/J mice. We found that the number of rods and the length of their outer segments were significantly reduced in 2.5-year-old mice compared with 4-month-old animals. Aging also resulted in a twofold reduction in the total level of opsin in the retina. Behavioral tests revealed that scotopic visual acuity and contrast sensitivity were decreased by twofold in aged mice, and rod ERG recordings demonstrated reduced amplitudes of both a- and b-waves. Sensitivity of aged rods determined from single-cell recordings was also decreased by 1.5-fold, corresponding to not more than 1% free opsin in these photoreceptors, and kinetic parameters of dim flash response were not altered. Notably, the rate of rod dark adaptation was unaffected by age. Thus, our results argue against age-related deficiency of 11-cis-retinal in the B6D2F1/J mouse rod visual cycle. Surprisingly, the level of cellular dark noise was increased in aged rods, providing an alternative mechanism for their desensitization.

  17. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report

    SciTech Connect

    Todreas, N.E.; Golay, M.W.; Wold, L.

    1981-02-01

    Four tasks are reported on: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical determination of local temperature fields in LMFBR fuel rod bundles. (DLC)

  18. Entropically dirven phase transitions in mixtures of colloidal rods and spheres.

    NASA Astrophysics Data System (ADS)

    Fraden, Seth

    2001-03-01

    We have prepared a homologous series of filamentous viruses with varying contour length using molecular cloning techniques. These viruses are monodisperse enough to form a stable smectic phase. Two systems are studied. The first system consists of viruses to which polymers are covalently attached to the virus surface. Through studies of the isotropic - cholesteric phase transition we demonstrate that covalently attached polymers alter the effective diameter of the virus and we have produced mixtures of viruses whose ratio of effective diameters varies by a factor of five. The second system is composed of mixtures of rod-like viruses and non-absorbing polymers. With this system we study the kinetics of the isotropic - smectic phase transition and describe observations of a number of novel metastable structures of unexpected complexity. Preprints are available online at www.elsie.brandeis.edu and at http://xxx.lanl.gov/abs/cond-mat/0010269.

  19. Two-photon pumped cavity lasing in novel dye doped bulk matrix rods

    NASA Astrophysics Data System (ADS)

    He, Guang S.; Zhao, Chan F.; Bhawalkar, Jayant D.; Prasad, Paras N.

    1995-12-01

    Trans-4-[p-(N-ethyl-N-hydroxyethylamino)styryl]-N-methylpyridi that possesses a much greater two-photon absorption cross section and much stronger upconversion fluorescence emission than common organic dyes (such as rhodamine), when excited with near infrared laser radiation. Utilizing ASPT doped bulk polymer rods, two-photon pumped frequency upconverted cavity lasing has been accomplished using a Q-switched Nd:YAG laser as the pump source. The wavelength and pulse duration were ˜600 nm and 3-6 ns, respectively, for the cavity lasing; whereas the corresponding values for pump pulses were 1.06 μm and ˜10 ns, respectively. For a 7 mm long sample rod with a dopant concentration d0=8×10-3 M/L, the conversion efficiency from the absorbed pump energy to the cavity lasing output was ˜3.5% at a pump energy level of 1.3 mJ. The lasing lifetime, in terms of pulse numbers, was more than 4×104 pulses at 2 Hz repetition rate and room temperature.

  20. Liquid crystal tunable metamaterial absorber.

    PubMed

    Shrekenhamer, David; Chen, Wen-Chen; Padilla, Willie J

    2013-04-26

    We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the metamaterial unit cell, we are able to modify the absorption by 30% at 2.62 THz, as well as tune the resonant absorption over 4% in bandwidth. Numerical full-wave simulations match well to experiments and clarify the underlying mechanism, i.e., a simultaneous tuning of both the electric and magnetic response that allows for the preservation of the resonant absorption. These results show that fundamental light interactions of surfaces can be dynamically controlled by all-electronic means and provide a path forward for realization of novel applications.

  1. Oxalate: Effect on calcium absorbability

    SciTech Connect

    Heaney, R.P.; Weaver, C.M. )

    1989-10-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species.

  2. Anisotropy in CdSe quantum rods

    SciTech Connect

    Li, Liang-shi

    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

  3. Dynamics of entangled rod-coil block copolymers

    NASA Astrophysics Data System (ADS)

    Wang, Muzhou; Timachova, Ksenia; Alexander-Katz, Alfredo; Likhtman, Alexei E.; Olsen, Bradley D.

    2014-03-01

    Polymer science is exploring advanced materials which combine functional domains such as proteins and semiconducting polymers with traditional flexible polymers onto the same molecule. While many studies have focused on equilibrium structure-property relationships, little is known about how the conformational restrictions of rigid domains affect dynamical phenomena such as mechanical properties, processing pathways, and self-assembly kinetics. We have recently introduced a reptation theory for entangled rod-coil block copolymers as a model for this wider class of functional polymeric materials. The theory hypothesizes that the motion of rod-coils is slowed relative to rod and coil homopolymers because of a mismatch between the curvature of the rod and coil entanglement tubes. This effect leads to activated reptation and arm retraction as two relaxation mechanisms that govern the short and long rod regimes, respectively. These results were verified by tracer diffusion measurements using molecular dynamics simulation and forced Rayleigh scattering in both the rod-coil diblock and coil-rod-coil triblock configurations. The tracer diffusion results were then compared to experimental self-diffusion measurements which require a consideration of the motion of the surrounding chains.

  4. Distant Harrington rod migration 35 years after implantation.

    PubMed

    Lark, Robert K; Caputo, Adam M; Brown, Christopher R; Michael, Keith W; Thacker, Julie K; Richardson, William J

    2013-10-01

    Harrington rods have been successfully implanted in thousands of patients for the correction of scoliotic deformity since the 1950s. An exceedingly rare complication of Harrington rod placement is loosening with resultant migration. The authors present a 50-year-old woman who had a single Harrington rod placed when she was 15 years old. Thirty-five years later, she presented with acute sensory changes in her lower extremities. Imaging revealed rod failure and migration of the hardware distally, resulting in penetration of the wall of the rectum. Due to the unique anatomical position of the migrated hardware, sigmoidoscopy was used to directly visualize and remove the rod. The patient ultimately made a full recovery. Rod migration is an exceedingly rare complication that has been described only a few times since the introduction of Harrington rods over 60 years ago. The case herein is particularly unique given the extensive period of time that passed before migration (35 years) and the use of sigmoidoscopy for hardware removal.

  5. Diffusion of spheres in crowded suspensions of rods

    NASA Astrophysics Data System (ADS)

    Kang, Kyongok; Gapinski, J.; Lettinga, M. P.; Buitenhuis, J.; Meier, G.; Ratajczyk, M.; Dhont, Jan K. G.; Patkowski, A.

    2005-01-01

    Translational tracer diffusion of spherical macromolecules in crowded suspensions of rodlike colloids is investigated. Experiments are done using several kinds of spherical tracers in fd-virus suspensions. A wide range of size ratios L/2a of the length L of the rods and the diameter 2a of the tracer sphere is covered by combining several experimental methods: fluorescence correlation spectroscopy for small tracer spheres, dynamic light scattering for intermediate sized spheres, and video microscopy for large spheres. Fluorescence correlation spectroscopy is shown to measure long-time diffusion only for relatively small tracer spheres. Scaling of diffusion coefficients with a/ξ, predicted for static networks, is not found for our dynamical network of rods (with ξ the mesh size of the network). Self-diffusion of tracer spheres in the dynamical network of freely suspended rods is thus fundamentally different as compared to cross-linked networks. A theory is developed for the rod-concentration dependence of the translational diffusion coefficient at low rod concentrations for freely suspended rods. The proposed theory is based on a variational solution of the appropriate Smoluchowski equation without hydrodynamic interactions. The theory can, in principle, be further developed to describe diffusion through dynamical networks at higher rod concentrations with the inclusion of hydrodynamic interactions. Quantitative agreement with the experiments is found for large tracer spheres, and qualitative agreement for smaller spheres. This is probably due to the increasing importance of hydrodynamic interactions as compared to direct interactions as the size of the tracer sphere decreases.

  6. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report, September 1, 1980-November 30, 1980

    SciTech Connect

    Todreas, N.E.; Golay, M.W.; Wolf, L.

    1981-02-01

    Four tasks are reported: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical determination of local temperature fields in LMFBR fuel rod bundles. (DLC)

  7. Electromagnetic scattering by pyramidal and wedge absorber

    NASA Technical Reports Server (NTRS)

    Dewitt, Brian T.; Burnside, Walter D.

    1988-01-01

    Electromagnetic scattering from pyramidal and wedge absorbers used to line the walls of modern anechoic chambers is measured and compared with theoretically predicted values. The theoretical performance for various angles of incidence is studied. It is shown that a pyramidal absorber scatters electromagnetic energy more as a random rough surface does. The apparent reflection coefficient from an absorber wall illuminated by a plane wave can be much less than the normal absorber specifications quoted by the manufacturer. For angles near grazing incidence, pyramidal absorbers give a large backscattered field from the pyramid side-faces or edges. The wedge absorber was found to give small backscattered fields for near-grazing incidence. Based on this study, some new guidelines for the design of anechoic chambers are advocated because the specular scattering models used at present do not appear valid for pyramids that are large compared to the wavelength.

  8. Magnetic field effects on microwave absorbing materials

    NASA Technical Reports Server (NTRS)

    Goldberg, Ira; Hollingsworth, Charles S.; Mckinney, Ted M.

    1991-01-01

    The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical.

  9. Interface Defeat of Long-Rod Projectiles by Ceramic Armor

    DTIC Science & Technology

    2005-09-01

    confinement was launched against a long, stationary rod of tungsten (W) heavy alloy (WHA). The long rod was observed by flash radiography as it interacted...demountable x-ray tubes with 2-mm-diameter anodes, were introduced later for greater resolution of detail. A tungsten wire fiducial in the moving...machined from full-scale projectiles, 33 mm in diameter, that had been swaged to reduce their cross-sectional area by 24%. The rods were 1.58 mm in

  10. Lateral suppression of mesopic rod and cone flicker detection

    PubMed Central

    Cao, Dingcai; Lu, Yolanda H.

    2012-01-01

    This study investigated the mechanisms of flicker detection suppression by measuring mesopic rod and cone critical flicker frequencies (CFFs) at different center and surround illuminance levels. Stimuli were generated with a four-primary photostimulator that provided independent control of rod and cone excitations. The results showed that dim surrounds ≤0.2 Td suppressed cone-mediated CFFs at ≥20 Td but not rod-mediated CFFs. These results can be understood in terms of peak amplitudes of photoreceptor impulse response functions under different stimulation conditions. PMID:22330377

  11. COAXIAL CONTROL ROD DRIVE MECHANISM FOR NEUTRONIC REACTORS

    DOEpatents

    Fox, R.J.; Oakes, L.C.

    1959-04-14

    A drive mechanism is presented for the control rod or a nuclear reactor. In this device the control rod is coupled to a drive shaft which extends coaxially through the rotor of an electric motor for relative rotation with respect thereto. A gear reduction mehanism is coupled between the rotor and the drive shaft to convert the rotary motion of the motor into linear motion of the shaft with a comparatively great reduction in speed, thereby providing relatively glow linear movement of the shaft and control rod for control purposes.

  12. System for fuel rod removal from a reactor module

    DOEpatents

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

    1988-07-28

    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 figs.

  13. System for fuel rod removal from a reactor module

    DOEpatents

    Matchett, Richard L.; Roof, David R.; Kikta, Thomas J.; Wilczynski, Rosemarie; Nilsen, Roy J.; Bacvinskas, William S.; Fodor, George

    1990-01-01

    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.

  14. Cleaning and excavating tool for control rod canopy seals

    SciTech Connect

    Kucera, R.A.

    1991-12-24

    This patent describes a device for servicing a weld site about the periphery of a control rod drive mechanism. It comprises a housing adapted to be rotated about the periphery of the control rod drive mechanism; a carriage reciprocably received within the housing; first movement means for reciprocating the carriage in a first direction; a tool attachment reciprocably received within the carriage; and second movement means for reciprocating the tool in a second direction; wherein the tool attachment is positioned relative to the control rod drive mechanism by the first and second movement means.

  15. 26. A typical outer rod room, or rack room, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. A typical outer rod room, or rack room, showing the racks for the nine horizontal control rods (HCRs) that would be inserted or withdrawn from the pile to control the rate of reaction. In this case, it is the 105-F Reactor in February 1945. The view is looking away from the pile, which is out of the picture on the left. Several of the cooling water hose reels for the rods can be seen at the end of the racks near the wall. D-8323 - B Reactor, Richland, Benton County, WA

  16. In vivo imaging of the human rod photoreceptor mosaic

    PubMed Central

    Doble, Nathan; Choi, Stacey S.; Codona, Johanan L.; Christou, Julian; Enoch, Jay M.; Williams, David R.

    2011-01-01

    Although single cone receptors have been imaged in the living human eye, there has been no observation of rods in vivo. Using an adaptive optics (AO) ophthalmoscope and post processing, evidence of rod mosaic was observed at 5° and 10° eccentricities in the horizontal, temporal retina. For 4 normal human subjects, small structures were observed in between the larger cones, and were observed repeatedly at the same locations on different days and with varying wavelengths. Image analysis gave spacings that agree well with rod measurements from histological data. PMID:21209677

  17. Rod gripper, changer, and storage system

    NASA Technical Reports Server (NTRS)

    Benson, Mark; Demi, Todd; Mcneill, Robert; Waldo, Keith; Afghan, Alex; Oliver, Jim

    1989-01-01

    A rod changer and storage design is presented for the lunar deep drill apparatus to be used in conjunction with the Skitter walking platform. The design must take into account all of the lunar environment and working conditions. Some of these are: (1) the moon has one sixth the gravity of earth; (2) temperature gradients can range from about -170 to 265 C; (3) because of the high transportation costs, the design must be as light as possible; and (4) the process must be remotely operated (from earth or satellite) and must be automated. Because of Skitter's multiple degree of freedom movement, the design will utilize Skitter's movement to locate an implement and transport it from the rack to the drill string. The implement will be gripped by a thumb and two finger device, identified through an electronic sensing device on the thumb, and transported from the rack to the footplate and back from the footplate to the rack. The major designs discussed in this report have been broken down into three major areas: (1) gripper design (linear transport mechanism); (2) indexing system; and (3) rack design.

  18. Large-eddy simulation, fuel rod vibration and grid-to-rod fretting in pressurized water reactors

    NASA Astrophysics Data System (ADS)

    Christon, Mark A.; Lu, Roger; Bakosi, Jozsef; Nadiga, Balasubramanya T.; Karoutas, Zeses; Berndt, Markus

    2016-10-01

    Grid-to-rod fretting (GTRF) in pressurized water reactors is a flow-induced vibration phenomenon that results in wear and fretting of the cladding material on fuel rods. GTRF is responsible for over 70% of the fuel failures in pressurized water reactors in the United States. Predicting the GTRF wear and concomitant interval between failures is important because of the large costs associated with reactor shutdown and replacement of fuel rod assemblies. The GTRF-induced wear process involves turbulent flow, mechanical vibration, tribology, and time-varying irradiated material properties in complex fuel assembly geometries. This paper presents a new approach for predicting GTRF induced fuel rod wear that uses high-resolution implicit large-eddy simulation to drive nonlinear transient dynamics computations. The GTRF fluid-structure problem is separated into the simulation of the turbulent flow field in the complex-geometry fuel-rod bundles using implicit large-eddy simulation, the calculation of statistics of the resulting fluctuating structural forces, and the nonlinear transient dynamics analysis of the fuel rod. Ultimately, the methods developed here, can be used, in conjunction with operational management, to improve reactor core designs in which fuel rod failures are minimized or potentially eliminated. Robustness of the behavior of both the structural forces computed from the turbulent flow simulations and the results from the transient dynamics analyses highlight the progress made towards achieving a predictive simulation capability for the GTRF problem.

  19. Large-eddy simulation, fuel rod vibration and grid-to-rod fretting in pressurized water reactors

    SciTech Connect

    Christon, Mark A.; Lu, Roger; Bakosi, Jozsef; Nadiga, Balasubramanya T.; Karoutas, Zeses; Berndt, Markus

    2016-10-01

    Grid-to-rod fretting (GTRF) in pressurized water reactors is a flow-induced vibration phenomenon that results in wear and fretting of the cladding material on fuel rods. GTRF is responsible for over 70% of the fuel failures in pressurized water reactors in the United States. Predicting the GTRF wear and concomitant interval between failures is important because of the large costs associated with reactor shutdown and replacement of fuel rod assemblies. The GTRF-induced wear process involves turbulent flow, mechanical vibration, tribology, and time-varying irradiated material properties in complex fuel assembly geometries. This paper presents a new approach for predicting GTRF induced fuel rod wear that uses high-resolution implicit large-eddy simulation to drive nonlinear transient dynamics computations. The GTRF fluid–structure problem is separated into the simulation of the turbulent flow field in the complex-geometry fuel-rod bundles using implicit large-eddy simulation, the calculation of statistics of the resulting fluctuating structural forces, and the nonlinear transient dynamics analysis of the fuel rod. Ultimately, the methods developed here, can be used, in conjunction with operational management, to improve reactor core designs in which fuel rod failures are minimized or potentially eliminated. Furthermore, robustness of the behavior of both the structural forces computed from the turbulent flow simulations and the results from the transient dynamics analyses highlight the progress made towards achieving a predictive simulation capability for the GTRF problem.

  20. Force-extension curves for broken-rod macromolecules: Dramatic effects of different probing methods for two and three rods

    SciTech Connect

    Alexeev, A. V.; Maltseva, D. V.; Ivanov, V. A.; Klushin, L. I.; Skvortsov, A. M.

    2015-04-28

    We study force-extension curves of a single semiflexible chain consisting of several rigid rods connected by flexible spacers. The atomic force microscopy and laser optical or magnetic tweezers apparatus stretching these rod-coil macromolecules are discussed. In addition, the stretching by external isotropic force is analyzed. The main attention is focused on computer simulation and analytical results. We demonstrate that the force-extension curves for rod-coil chains composed of two or three rods of equal length differ not only quantitatively but also qualitatively in different probe methods. These curves have an anomalous shape for a chain of two rods. End-to-end distributions of rod-coil chains are calculated by Monte Carlo method and compared with analytical equations. The influence of the spacer’s length on the force-extension curves in different probe methods is analyzed. The results can be useful for interpreting experiments on the stretching of rod-coil block-copolymers.

  1. Large-eddy simulation, fuel rod vibration and grid-to-rod fretting in pressurized water reactors

    DOE PAGES

    Christon, Mark A.; Lu, Roger; Bakosi, Jozsef; ...

    2016-10-01

    Grid-to-rod fretting (GTRF) in pressurized water reactors is a flow-induced vibration phenomenon that results in wear and fretting of the cladding material on fuel rods. GTRF is responsible for over 70% of the fuel failures in pressurized water reactors in the United States. Predicting the GTRF wear and concomitant interval between failures is important because of the large costs associated with reactor shutdown and replacement of fuel rod assemblies. The GTRF-induced wear process involves turbulent flow, mechanical vibration, tribology, and time-varying irradiated material properties in complex fuel assembly geometries. This paper presents a new approach for predicting GTRF induced fuelmore » rod wear that uses high-resolution implicit large-eddy simulation to drive nonlinear transient dynamics computations. The GTRF fluid–structure problem is separated into the simulation of the turbulent flow field in the complex-geometry fuel-rod bundles using implicit large-eddy simulation, the calculation of statistics of the resulting fluctuating structural forces, and the nonlinear transient dynamics analysis of the fuel rod. Ultimately, the methods developed here, can be used, in conjunction with operational management, to improve reactor core designs in which fuel rod failures are minimized or potentially eliminated. Furthermore, robustness of the behavior of both the structural forces computed from the turbulent flow simulations and the results from the transient dynamics analyses highlight the progress made towards achieving a predictive simulation capability for the GTRF problem.« less

  2. Absorbent product and articles made therefrom

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

  3. Nonlinear dynamic vibration absorbers with a saturation

    NASA Astrophysics Data System (ADS)

    Febbo, M.; Machado, S. P.

    2013-03-01

    The behavior of a new type of nonlinear dynamic vibration absorber is studied. A distinctive characteristic of the proposed absorber is the impossibility to extend the system to infinity. The mathematical formulation is based on a finite extensibility nonlinear elastic potential to model the saturable nonlinearity. The absorber is attached to a single degree-of-freedom linear/nonlinear oscillator subjected to a periodic external excitation. In order to solve the equations of motion and to analyze the frequency-response curves, the method of averaging is used. The performance of the FENE absorber is evaluated considering a variation of the nonlinearity of the primary system, the damping and the linearized frequency of the absorber and the mass ratio. The numerical results show that the proposed absorber has a very good efficiency when the nonlinearity of the primary system increases. When compared with a cubic nonlinear absorber, for a large nonlinearity of the primary system, the FENE absorber shows a better effectiveness for the whole studied frequency range. A complete absence of quasi-periodic oscillations is also found for an appropriate selection of the parameters of the absorber. Finally, direct integrations of the equations of motion are performed to verify the accuracy of the proposed method.

  4. Metamaterial absorber with random dendritic cells

    NASA Astrophysics Data System (ADS)

    Zhu, Weiren; Zhao, Xiaopeng

    2010-05-01

    The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

  5. Application of Burnable Absorbers in an Accelerator-Driven System

    SciTech Connect

    Wallenius, Jan; Tucek, Kamil; Carlsson, Johan; Gudowski, Waclaw

    2001-01-15

    The application of burnable absorbers (BAs) to minimize power peaking, reactivity loss, and capture-to-fission probabilities in an accelerator-driven waste transmutation system has been investigated. Boron-10-enriched B{sub 4}C absorber rods were introduced into a lead-bismuth-cooled core fueled with transuranic (TRU) discharges from light water reactors to achieve the smallest possible power peakings at beginning-of-life (BOL) subcriticality level of 0.97. Detailed Monte Carlo simulations show that a radial power peaking equal to 1.2 at BOL is attainable using a four-zone differentiation in BA content. Using a newly written Monte Carlo burnup code, reactivity losses were calculated to be 640 pcm per percent TRU burnup for unrecycled TRU discharges. Comparing to corresponding values in BA-free cores, BA introduction diminishes reactivity losses in TRU-fueled subcritical cores by {approx}20%. Radial power peaking after 300 days of operation at 1200-MW thermal power was <1.75 at a subcriticality level of {approx}0.92, which appears to be acceptable, with respect to limitations in cladding and fuel temperatures. In addition, the use of BAs yields significantly higher fission-to-capture probabilities in even-neutron-number nuclides. Fission-to-absorption probability ratio for {sup 241}Am equal to 0.33 was achieved in the configuration studied. Hence, production of the strong alpha-emitter {sup 242}Cm is reduced, leading to smaller fuel-swelling rates and pin pressurization. Disadvantages following BA introduction, such as increase of void worth and decrease of Doppler feedback in conjunction with small values of {beta}{sub eff}, need to be addressed by detailed studies of subcritical core dynamics.

  6. Sorptive physiologically based extraction of contaminated solid matrices: incorporating silicone rod as absorption sink for hydrophobic organic contaminants.

    PubMed

    Gouliarmou, Varvara; Collins, Chris D; Christiansen, Ellen; Mayer, Philipp

    2013-01-15

    The oral bioaccessibility of soil contaminants is increasingly assessed with physiologically based extraction tests (PBETs): the contaminant fraction that is desorbed into simulated digestive fluids is measured and classified as bioaccessible. However, this approach can lead to underestimations if the capacity of the fluids is insufficient to provide infinite sink conditions. Desorption will then progressively decrease and finally stop when equilibrium between soil and medium is reached. To circumvent this artifact, we incorporated a silicone rod as an absorption sink into the PBET to continuously absorb mobilized contaminants and maintain the desorption gradient. Polycyclic aromatic hydrocarbons served as model contaminants and the colon extended PBET as the extraction model. The inclusion of the silicone rod sink (1) increased the extraction capacity of the test by orders of magnitude, (2) ensured near infinite sink conditions, and (3) allowed for simple back-extraction of PAHs for their quantification by GC-MS. The silicone rod provided fast enrichment when applied to the stomach and small intestine compartment, but was somewhat slower in the richer colon compartment. Finally, the sorptive-PBET was applied to wood soot and a kindergarten soil. The present article provides the basis for how an absorption sink can be integrated into PBET models.

  7. Self-assembly of DNA origami particles in suspension of non-absorbing depleting polymers

    NASA Astrophysics Data System (ADS)

    Siavashpouri, Mahsa; Zakhary, Mark; Wachauf, Christian; Dietz, Hendrik; Dogic, Zvonimir

    2015-03-01

    The connection between the macroscopic properties of a liquid crystalline material and the microscopic features of the constituent molecules is the essential theme that permeates the field of liquid crystals. Previous studies have shown that monodisperse rod-like colloids such as filamentous bacteriophage self-assemble into 1D twisted ribbons in presence of attractive interactions mediated by non-absorbing polymers. The microscopic properties of the colloidal particles play an important role in determining the physical properties of these mesoscopic assemblages. Using structural DNA nanotechnology, we present the design and structure of DNA origami six-helix bundles with tunable microscopic properties, which can be used as a new building block for the self-assembly of rod-like colloidal particles. We demonstrate that formation of higher order structures from the assembly of colloidal rods is universal. By tuning the chirality, aspect ratio and flexibility of the DNA origami particles we can control the physical properties of the entire self-assembled structures.

  8. 25. DETAIL OF TIE ROD REINFORCING BELOW WESTERNMOST MOVABLE STAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. DETAIL OF TIE ROD REINFORCING BELOW WESTERNMOST MOVABLE STAGE SECTION, LOWER LEVEL OF STAGE, LOOKING SOUTH. TAKEN FROM A POINT JUST SOUTH OF RAM IN IL-1007-24. - Auditorium Building, 430 South Michigan Avenue, Chicago, Cook County, IL

  9. Scaled Long Rod Perforation Experiments Using Multiple Diagnostics

    NASA Astrophysics Data System (ADS)

    Cross, Daniel; Proud, William

    2011-06-01

    A series of angled small-scale reverse ballistic long rod experiments were conducted using mild steel rods (6 mm dia., 90 mm long) against both 3 mm and 6 mm rolled homogeneous armour (RHA) plates at 30°. The impact velocity was varied from 450-780 m s-1 and the response of the system monitored by laser velocimetry, strain gauges and high-speed photography. This provided insight into the flexing of the rod during impact, the acceleration of the rear of the rod and the global penetration process. This experimental series involved ricochet, near-ricochet and full perforation, and so allows the sensitivity of the differing diagnostic outputs for these processes to be compared.

  10. Process-based tolerance assessment of connecting rod machining process

    NASA Astrophysics Data System (ADS)

    Sharma, G. V. S. S.; Rao, P. Srinivasa; Surendra Babu, B.

    2016-01-01

    Process tolerancing based on the process capability studies is the optimistic and pragmatic approach of determining the manufacturing process tolerances. On adopting the define-measure-analyze-improve-control approach, the process potential capability index ( C p) and the process performance capability index ( C pk) values of identified process characteristics of connecting rod machining process are achieved to be greater than the industry benchmark of 1.33, i.e., four sigma level. The tolerance chain diagram methodology is applied to the connecting rod in order to verify the manufacturing process tolerances at various operations of the connecting rod manufacturing process. This paper bridges the gap between the existing dimensional tolerances obtained via tolerance charting and process capability studies of the connecting rod component. Finally, the process tolerancing comparison has been done by adopting a tolerance capability expert software.

  11. Rod shop, roof and truss detail showing older pink roof ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rod shop, roof and truss detail showing older pink roof truss, newer pratt truss, and longitudinal, truss for overhead traveling crane - Chicago, Burlington & Quincy Railroad, Roundhouse & Shops, Broadway & Spring Streets, Aurora, Kane County, IL

  12. Inertial Range Scaling in Rotations of Long Rods in Turbulence

    NASA Astrophysics Data System (ADS)

    Voth, Greg; Parsa, Shima

    2013-11-01

    We measure the rotational statistics of neutrally buoyant rods with lengths 2 . 8 < l / η < 72 . 9 in turbulence. For particles with length in the inertial range, we derive a scaling relationship for the mean square rotation rate, <ṗiṗi > ~l - 4 / 3 and show that measurements approach this scaling. Deviations from the proposed scaling are explained as the effect of dissipation range scales. The correlation time of the Lagrangian autocorrelation of rod rotation rate scales as the turn over time of eddies of the size of the rod. Measuring rotational dynamics of single long rods provides a new way to access the dynamics of turbulence at fixed spatial scale in a frame advected with the flow. Supported by NSF grant DMR-1208990.

  13. 43 CFR 2094.2 - Waiver of 160-rod limitation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Special Resource Values; Shore Space § 2094.2 Waiver of 160-rod limitation. (a) The Act of June 5, 1920 (41...

  14. 43 CFR 2094.2 - Waiver of 160-rod limitation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Special Resource Values; Shore Space § 2094.2 Waiver of 160-rod limitation. (a) The Act of June 5, 1920 (41...

  15. 43 CFR 2094.2 - Waiver of 160-rod limitation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Special Resource Values; Shore Space § 2094.2 Waiver of 160-rod limitation. (a) The Act of June 5, 1920 (41...

  16. 43 CFR 2094.2 - Waiver of 160-rod limitation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MANAGEMENT, DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Special Resource Values; Shore Space § 2094.2 Waiver of 160-rod limitation. (a) The Act of June 5, 1920 (41...

  17. End of truss showing upper chord, bottom chord rod, compression ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    End of truss showing upper chord, bottom chord rod, compression strut and connector - Central of Georgia Railway, Passenger Station & Train Shed, Corner of Louisville (Railroad) Road & West Broad Street, Savannah, Chatham County, GA

  18. DETAIL VIEW OF LOWER CHORD CONNECTIONS AND SAG RODS, SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF LOWER CHORD CONNECTIONS AND SAG RODS, SOUTH TRUSS, EAST END, LOOKING NORTHWEST - Henszey's Wrought-Iron Arch Bridge, Spanning Ontelaunee Creek at Kings Road, Wanamakers, Lehigh County, PA

  19. Self-monitoring Composite Rods for Sustainable Construction

    NASA Astrophysics Data System (ADS)

    Gonilho-Pereira, Cristiana; Zdraveva, Emilija; Fangueiro, Raul; Lanceros-Mendez, S.; Jalali, Said; de Araújo, Mário

    This paper presents the development and properties assessment of braided reinforced composite rods (BCR) able to both reinforce and monitor the stress state of concrete infrastructures. The research study aims at understanding the tensile behaviour and self-monitoring ability of composite rods reinforced by a textile structure - braided structure with core reinforcement - for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute, in order to improve structures safety and sustainability. Seven types of braided composite rods have been produced using an author patented technique based on a modified conventional braiding machine. The tensile properties of the braided reinforced composite rods were evaluated in order to identify the type(s) of fibre(s) to be used as core reinforcement. BCR have been tested under bending while the variation of the electrical resistance was simultaneously monitored.

  20. 31. DETAIL OF DIAGONAL REINFORCING RODS TYPICAL OF FLOORS IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. DETAIL OF DIAGONAL REINFORCING RODS TYPICAL OF FLOORS IN CLASSROOMS AT NORTH PORTIONS OF EAST AND WEST WINGS - Frederika Bremer Intermediate School, 1214 Lowry Avenue North, Minneapolis, Hennepin County, MN

  1. Development of visual and tactile rod orientation in children.

    PubMed

    Meerwaldt, J D; Schmitz, P I

    1988-09-15

    Two groups of neurologically normal children (total number 64), aged from 4 to 13 years, were examined with the rod orientation test. In the second group, the line orientation test and finger tapping were also studied in addition to the rod orientation test. On the rod orientation test, the mean error rates decreased with age in both groups, and from the age of 10 the children performed as well as normal adults. In the period (ages 4-7 years) in which the greatest change in performance on the visual part of the rod orientation test had taken place (63%), a much smaller change occurred in the tapping frequency (23%). Thus the development of motor skills does not seem to be directly related to the development of spatial perception. The line orientation test did not show any developmental profile.

  2. 39. Detail view of No. 2 Furnace iron runner; rod ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. Detail view of No. 2 Furnace iron runner; rod or poker at right was used to unplug iron notch. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  3. 7. DETAIL VIEW UNDER BRIDGE OF CORRUGATED STEEL, BEAMS, RODS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. DETAIL VIEW UNDER BRIDGE OF CORRUGATED STEEL, BEAMS, RODS, AND ABUTMENT - Price River Bridge, Spanning Price River, 760 North Street in Carbonville, 1 mile northwest of Price, Carbonville, Carbon County, UT

  4. 13. View of disassembled steam engine showing cylinder, piston rod, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. View of disassembled steam engine showing cylinder, piston rod, parallel motion links and steam chest. - Hacienda Azucarera La Esperanza, Steam Engine & Mill, 2.65 Mi. N of PR Rt. 2 Bridge over Manati River, Manati, Manati Municipio, PR

  5. 14. DETAIL VIEW OF ESCAPE TRAINING TANK, SHOWING HOLDDOWN RODS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAIL VIEW OF ESCAPE TRAINING TANK, SHOWING HOLD-DOWN RODS, LOOKING SOUTH - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  6. 28. VIEW OF OCTAGONAL SPREAD FOOTING AND HOLDDOWN RODS 1929, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. VIEW OF OCTAGONAL SPREAD FOOTING AND HOLD-DOWN RODS 1929, SUBMARINE ESCAPE TRAINING TANK - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT

  7. 9. Detail of gears and connection rod to sluice gate ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Detail of gears and connection rod to sluice gate - Mississippi River 9-Foot Channel, Lock & Dam No. 1, In Mississippi River at Mississippi Boulevard, below Ford Parkway Bridge, Saint Paul, Ramsey County, MN

  8. Exploring Light’s Interactions with Bubbles and Light Absorbers in Photoelectrochemical Devices using Ray Tracing

    SciTech Connect

    Stevens, John Colby

    2012-12-01

    Ray tracing was used to perform optical optimization of arrays of photovoltaic microrods and explore the interaction between light and bubbles of oxygen gas on the surface of the microrods. The incident angle of light was varied over a wide range. The percent of incident light absorbed by the microrods and reflected by the bubbles was computed over this range. It was found that, for the 10 μm diameter, 100 μm tall SrTiO3 microrods simulated in the model, the optimal center-­to-­center spacing was 14 μm for a square grid. This geometry produced 75% average and 90% maximum absorbance. For a triangular grid using the same microrods, the optimal center-­to-­center spacing was 14 μm. This geometry produced 67% average and 85% maximum absorbance. For a randomly laid out grid of 5 μm diameter, 100 μm tall SrTiO3 microrods with an average center-­to-­center spacing of 20 μm, the average absorption was 23% and the maximum absorption was 43%. For a 50% areal coverage fraction of bubbles on the absorber surface, between 2%-­20% of the incident light energy was reflected away from the rods by the bubbles, depending upon incident angle and bubble morphology.

  9. Super-absorbency and phase transition of gels in physiological salt solutions

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Qing; Tanaka, Toyoichi; Shibayama, Mitsuhiro

    1992-11-01

    IONIC gels with the ability to absorb many times their dry weight of water have found widespread use as absorbents in medical, chemical and agricultural applications1. The dramatic swelling power of these super-absorbent gels results from both the electrostatic repulsion between the charges on the polymer chains, and the osmotic pressure of the counter-ions2. In salt solutions such as saline, urine or blood, however, excess Na+ and Cl- ions screen the polymer charges and eliminate the osmotic imbalance, effectively changing the properties of the material to that of a non-ionic gel3: this greatly diminishes the swelling power, and hence the utility of these materials under physiological conditions. Here we report the development of a system combining a non-ionic gel with ionized surfactants, which shows super-absorbent behaviour even in the presence of salt. In water, the hydrophobic gel facilitates the formation of spherical surfactant micelles, which mimic the charged sites of an ionic gel. As the salt concentration is increased, the micelles become rod-like, maintaining the electrostatic repulsion along the polymer chains and thereby preserving the swelling power of the gel.

  10. Device for absorbing mechanical shock

    DOEpatents

    Newlon, C.E.

    1979-08-29

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  11. Device for absorbing mechanical shock

    DOEpatents

    Newlon, Charles E.

    1980-01-01

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  12. Infrared non-planar plasmonic perfect absorber for enhanced sensitive refractive index sensing

    NASA Astrophysics Data System (ADS)

    Cheng, Yongzhi; Mao, Xue Song; Wu, Chenjun; Wu, Lin; Gong, RongZhou

    2016-03-01

    We present a non-planar all-metal plasmonic perfect absorber (PA) with response polarization independent in infrared region, which can be served as a sensor for enhanced refractive index sensing. Distinct from previous designs, the proposed PA consisted of all metal structured film constructed with an assembly of four-tined rod resonators (FRRs). The PA with a high quality-factor (Q-factor) of 41.2 and an absorbance of 99.9% at 142.6 THz has been demonstrated numerically. The resonance behavior occurs in the space between the rods of the FRRs, which is remarkable different conventional sandwiched structural PAs. Based on equivalent LC circuit theory, the absorption peak can be finely tuned by varying the geometrical dimensions of the FRRs. Furthermore, the resonance frequency shows highly sensitive response to the change of refractive index in the surrounding medium. A careful design for refractive index sensor can yield a sensitivity of 1445 nm/refractive index unit (RIU) and a figure of merit (FOM) of 28.8. The demonstrated design of the plasmonic PA for sensing provides great potential application in enhancing refractive index sensors and the enhanced infrared spectroscopy.

  13. Double-clad nuclear-fuel safety rod

    DOEpatents

    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. Apparatus for injection casting metallic nuclear energy fuel rods

    DOEpatents

    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.

  15. BWR fuel rod performance evaluation program. Final report

    SciTech Connect

    Rowland, T.C.

    1986-05-01

    The joint EPRI/GE fuel performance program, RP510-1, involved thorough preirradiation characterization of fuel used in lead test assemblies, detailed surveillance of their operation, and interim site examinations of the assemblies during reactor outages. The program originally included four GE-5 lead test assemblies operating in the Peach Bottom-2 reactor. The program was later modified to include the pressurized fuel rod test assembly in the Peach Bottom-3 reactor (RP510-2). The program modification also included extending the operation of the Peach Bottom-2 and Peach Bottom-3 lead test assembly fuel beyond normal discharge exposures. Interim site examination results following the first four cycles of operation of the Peach Bottom-2 lead test assemblies up to 35 GWd/MT and the examination of the Peach Bottom-3 pressurized test assembly at 32 GWd/MT are presented in this report. Elements of the examinations included visual examination of the fuel bundles; individual fuel rod visual examinations, rod length measurements, ultrasonic and eddy current nondestructive testing, Zircaloy cladding oxide thickness measurements and fission gas measurements. Channel measurements were made on the PB-2 Lead Test Assemblies after each of the first three operating cycles. All of the bundles were found to be in good condition. Since the pressurized test assembly contained pressurized and nonpressurized fuel rods in symmetric positions, it was possible to make direct comparisons of the fission gas release from pairs of pressurized and nonpressurized fuel rods with identical power histories. With one exception, the release was less from the pressurized fuel rod of each pair. Fuel rod power histories were calculated using new physics methods for all of the fuel rods that were punctured for fission gas release measurements. 28 refs., 41 figs., 16 tabs.

  16. Final design review of boron carbide safety rod

    SciTech Connect

    Lutz, R.N.

    1991-09-24

    The object of this paper discusses the design review of the boron carbide safety rod for the Westinghouse Savannah River Company. This paper reviewed information presented by personnel of the Savannah River Laboratory (SRL) Equipment Engineering Section, SRL Materials Technology Section and Reactor Materials Engineering and Technology. From this report, views, opinions and recommendations were made on the safety rod from materials testing to production.

  17. Actin dynamics and cofilin-actin rods in Alzheimer disease

    PubMed Central

    Bamburg, James R.; Bernstein, Barbara W.

    2017-01-01

    Cytoskeletal abnormalities and synaptic loss, typical of both familial and sporadic Alzheimer disease (AD), are induced by diverse stresses such as neuroinflammation, oxidative stress, and energetic stress, each of which may be initiated or enhanced by proinflammatory cytokines or amyloid-β (Aβ) peptides. Extracellular Aβ-containing plaques and intracellular phospho-tau-containing neurofibrillary tangles are postmortem pathologies required to confirm AD and have been the focus of most studies. However, AD brain, but not normal brain, also have increased levels of cytoplasmic rod-shaped bundles of filaments composed of ADF/cofilin-actin in a 1:1 complex (rods). Cofilin, the major ADF/cofilin isoform in mammalian neurons, severs actin filaments at low cofilin/actin ratios and stabilizes filaments at high cofilin/actin ratios. It binds cooperatively to ADP-actin subunits in F-actin. Cofilin is activated by dephosphorylation and may be oxidized in stressed neurons to form disulfide-linked dimers, required for bundling cofilin-actin filaments into stable rods. Rods form within neurites causing synaptic dysfunction by sequestering cofilin, disrupting normal actin dynamics, blocking transport, and exacerbating mitochondrial membrane potential loss. Aβ and proinflammatory cytokines induce rods through a cellular prion protein-dependent activation of NADPH oxidase and production of reactive oxygen species. Here we review recent advances in our understanding of cofilin biochemistry, rod formation, and the development of cognitive deficits. We will then discuss rod formation as a molecular pathway for synapse loss that may be common between all three prominent current AD hypotheses, thus making rods an attractive therapeutic target. PMID:26873625

  18. Bead-rod-spring models in random flows

    NASA Astrophysics Data System (ADS)

    Plan, Emmanuel Lance Christopher Medillo, VI; Ali, Aamir; Vincenzi, Dario

    2016-08-01

    Bead-rod-spring models are the foundation of the kinetic theory of polymer solutions. We derive the diffusion equation for the probability density function of the configuration of a general bead-rod-spring model in short-correlated Gaussian random flows. Under isotropic conditions, we solve this equation analytically for the elastic rhombus model introduced by Curtiss, Bird, and Hassager [Adv. Chem. Phys. 35, 31 (1976)].

  19. Some Aspects of Research on Mechanics of Thin Elastic Rod

    NASA Astrophysics Data System (ADS)

    Yanzhu, Liu; Yun, Xue

    2013-07-01

    Some aspects of research wok on the mechanics of thin elastic rod based on Kirchhoff-Cosserat's model were summarized. The analytical mechanics with arc-coordinate s and time t as double variables was established to formulate the motion of elastic rod. In stability analysis the difference and relationship between Lyapunov's stability and Euler's stability were discussed. The first approximate stability was determined by the characteristic equation with double eigenvalues in different domains, one of which can be determined by geometric conditions in static analysis. The Lyapunov's and Euler's stability conditions of the rod in space domain are the necessary conditions of Lyapunov's stability in time domain. As applications of the Kirchhoff's rod in molecular biology, the explanations of nucleosome structure and the chromosome coiling of DNA were given. Concerning the application in engineering the shape of a hanging rod under gravity and the coiling and stretching process of an extendable space mast were discussed. The motion of an axial moving beam with constant velocity and axial extensive force was discussed as an example of exact Cosserat's rod, the special case of small deformation is the Timoshenko's beam.

  20. Shell runs 14,500-ft sucker rod completion

    SciTech Connect

    Wilson, J.W.

    1982-12-01

    Discusses a well in Wyoming's Reno field which features a modified downhole pump, a custom-made polished rod, and a special electric motor. String design was augmented by Shell's RodCal computer program that calculates load, stress, torque, horsepower requirements, stroke length, strokes per minute, and rod length and number. The pump is a 1 1/4-in. RHBM (API Spec. 11AX-B12) with an 11/16-in. valve rod. The polished rod is 30-ft long with a 1 1/2 diam, with a shoulder at the bottom and a conventional end at the top. The steel tapered rod string is a binary construction, run in 25-ft sections. The length of the string presented problems on the surface. To avoid midstring shock loading, Shell used an ultrahigh slip motor which slows from 1,170 to approximately 800 rpm on the downstroke to allow the string time to synchronize before starting the upstroke. The 70 b/d rate is expected to increase as the Reno field is under waterflood.

  1. Hydraulic testing of accelerator-production-of-tritium rod bundles

    SciTech Connect

    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 < P/D < 1.17, and d = 3.175 mm). Flows cover the range from greater-than-nominal Reynolds numbers (fully turbulent) to low-speed laminar flows. Differential pressure measurements were made across the support plates holding the rod bundles, across the rod bundles, and across the entire assembly. Flow rates, temperatures, and gauge pressures also were measured. The data from these hydraulic tests have been compared to correlating literature for tightly pitched rod bundles. The prototypic geometry of these tests did not compare directly to any geometry found in the literature because of the variety of subchannels along the outer wall of the rod bundle. Under that constraint, there was excellent comparison of the rod-bundle friction factor with those factors given in the literature. The results show a large range of the Reynolds number over which the flow is in transition from laminar to turbulent (e.g., 580 < Re{sub Tr} < 13,000). Also presented is the comparison of the overall rung pressure drop to a solution based on hydraulic-resistance handbook calculations.

  2. Swimming in a suspension of rod-like molecules

    NASA Astrophysics Data System (ADS)

    Shi, Juan; Powers, Thomas

    2016-11-01

    In nature, it is common for microorganisms to swim in fluids with microstructure, such as mucus. Motivated by this fact, there have been many recent theoretical, computational, and experimental studies of idealized swimmers in a dilute solution of flexible polymers. Here we study this problem from a different point of view by considering swimmers in a dilute solution of rigid rod-like polymers. We study the prescribed swimming problem of Taylor's sheet in a dilute suspension of non-Brownian rods. Using a simple continuum constitutive law for the suspension that describes the stress in terms of velocity gradient and local rod orientation, we calculate swimming speed to second order in the amplitude of the wave. Due to stresses induced by the presence of the rods, the first-order flow field differs from that of the Newtonian case. We find that the swimming speed increases linearly with rod concentration: the presence of the rods always makes the swimmer go faster. We also consider the problem of a finite swimmer by studying a two-dimensional circular squirmer. The squirmer is defined as a circle with a prescribed tangential slip velocity that leads to propulsion. By varying the prescribed slip boundary condition, we study both pushers and pullers.

  3. Experimental and computational studies of rod-deployment mechanisms

    SciTech Connect

    Schwalbe, L.A.; Wingate, C.A.; Stofleth, J.H.; Greene, R.W.

    1996-08-01

    We describe experimental measurements and hydrocode simulations of two tests in which long (L/D=12), steel rods were accelerated laterally with charges of Detasheet-C high explosive (HE). In each test configuration, 84 rods were initially aligned parallel to one another in an array of four concentric rings. The first test had a central core of HE that dispersed the rods isotropically. The second test had a narrow, 180 degree strip of HE on one side of the assembly that focused the rods directionally. Using radiographic data taken at several milliseconds after HE initiation, we measured the dynamic distributions of the rods, and their translational velocities and tumble rates. To compare with the data, we also modeled the experiments with our smooth particle hydrocode SPHINX. Within the context of our numerical model, the hydrocode results agree satisfactorily with the test data. We include in our discussion many of the inferences and insights that our results provide to the phenomenology and performance of multimode, rod-deployment mechanisms.

  4. Fission gas release restrictor for breached fuel rod

    DOEpatents

    Kadambi, N. Prasad; Tilbrook, Roger W.; Spencer, Daniel R.; Schwallie, Ambrose L.

    1986-01-01

    In the event of a breach in the cladding of a rod in an operating liquid metal fast breeder reactor, the rapid release of high-pressure gas from the fission gas plenum may result in a gas blanketing of the breached rod and rods adjacent thereto which impairs the heat transfer to the liquid metal coolant. In order to control the release rate of fission gas in the event of a breached rod, the substantial portion of the conventional fission gas plenum is formed as a gas bottle means which includes a gas pervious means in a small portion thereof. During normal reactor operation, as the fission gas pressure gradually increases, the gas pressure interiorly of and exteriorly of the gas bottle means equalizes. In the event of a breach in the cladding, the gas pervious means in the gas bottle means constitutes a sufficient restriction to the rapid flow of gas therethrough that under maximum design pressure differential conditions, the fission gas flow through the breach will not significantly reduce the heat transfer from the affected rod and adjacent rods to the liquid metal heat transfer fluid flowing therebetween.

  5. Evaluation of ceramic packed-rod regenerator matrices

    NASA Technical Reports Server (NTRS)

    Lawless, W. N.; Arenz, R. W.

    1981-01-01

    An extensive evaluation of a modified cryocooler with various regenerator matrices is reported. The matrices examined are 0.015 in. diam. Pb spheres and 0.008, 0.015, and 0.030 in. diam. rods of a 0.2% SnCl2 doped ceramic labelled LS-8A. Specific heat and thermal conductivity data on these rod materials are also reported. The chronic pulverization/dusting problem common to Pb spheres was investigated. During a 1000 hr life test with 0.0008 in. diam. rods there was no degradation of the refrigerator performance, and a subsequent examination of the rods themselves revealed no evidence of breakage or pulverization. The load temperature characteristics for the rod packed regenerators were inferior to that for the Pb spheres, the effect being to shift the Pb spheres load curve up in temperature. This temperature shift was 5.0, 7.4, and 11.6K for the 0.0008, 0.015, and 0.030 in. diam. rods, respectively.

  6. Vibrational Power Flow Analysis of Rods and Beams

    NASA Technical Reports Server (NTRS)

    Wohlever, James Christopher; Bernhard, R. J.

    1988-01-01

    A new method to model vibrational power flow and predict the resulting energy density levels in uniform rods and beams is investigated. This method models the flow of vibrational power in a manner analogous to the flow of thermal power in a heat conduction problem. The classical displacement solutions for harmonically excited, hysteretically damped rods and beams are used to derive expressions for the vibrational power flow and energy density in the rod and beam. Under certain conditions, the power flow in these two structural elements will be shown to be proportional to the energy density gradient. Using the relationship between power flow and energy density, an energy balance on differential control volumes in the rod and beam leads to a Poisson's equation which models the energy density distribution in the rod and beam. Coupling the energy density and power flow solutions for rods and beams is also discussed. It is shown that the resonant behavior of finite structures complicates the coupling of solutions, especially when the excitations are single frequency inputs. Two coupling formulations are discussed, the first based on the receptance method, and the second on the travelling wave approach used in Statistical Energy Analysis. The receptance method is the more computationally intensive but is capable of analyzing single frequency excitation cases. The traveling wave approach gives a good approximation of the frequency average of energy density and power flow in coupled systems, and thus, is an efficient technique for use with broadband frequency excitation.

  7. Americium Transmutation Feasibility When Used as Burnable Absorbers - 12392

    SciTech Connect

    Barbaras, Sean A.; Knight, Travis W.

    2012-07-01

    The use of plutonium in Mixed Oxide (MOX) fuel in traditional Pressurized Water Reactor (PWR) assemblies leads to greater americium production which is not addressed in MOX recycling. The transuranic nuclides (TRU) contribute the most to the radiotoxicity of nuclear waste and a reduction of the TRU stockpile would greatly reduce the overall radiotoxicity of what must be managed. Am-241 is a TRU of particular concern because it is the dominant contributor of total radiotoxicity for the first 1000 years in a repository. This research explored the feasibility of transmuting Am-241 by using varying amounts in MOX rods being used in place of burnable absorbers and evaluated with respect to the impact on incineration and transmutation of transuranics in MOX fuel as well as the impact on safety. This research concludes that the addition of americium to a non-uniform fuel assembly is a viable method of transmuting Am-241, holding down excess reactivity in the core while serving as a burnable poison, as well as reducing the radiotoxicity of high level waste that must be managed. The use of Am/MOX hybrid fuel assemblies to transmute americium was researched using multiple computer codes. Am-241 was shown in this study to be able to hold down excess reactivity at the beginning of cycle and shape the power distribution in the core with assemblies of varying americium content loaded in a pattern similar to the traditional use of assemblies with varying amounts of burnable absorbers. The feasibility, safety, and utility of using americium to create an Am/MOX hybrid non-uniform core were also evaluated. The core remained critical to a burnup of 22,000 MWD/MTM. The power coefficient of reactivity as well as the temperature and power defects were sufficiently negative to provide a prompt feedback mechanism in case of a transient and prevent a power excursion, thus ensuring inherent safety and protection of the core. As shown here as well as many other studies, this non

  8. Absorbencies of six different rodent beddings: commercially advertised absorbencies are potentially misleading.

    PubMed

    Burn, C C; Mason, G J

    2005-01-01

    Moisture absorbency is one of the most important characteristics of rodent beddings for controlling bacterial growth and ammonia production. However, bedding manufacturers rarely provide information on the absorbencies of available materials, and even when they do, absorption values are usually expressed per unit mass of bedding. Since beddings are usually placed into cages to reach a required depth rather than a particular mass, their volumetric absorbencies are far more relevant. This study therefore compared the saline absorbencies of sawdust, aspen woodchips, two virgin loose pulp beddings (Alpha-Dri and Omega-Dri), reclaimed wood pulp (Tek-Fresh), and corncob, calculated both by volume and by mass. Absorbency per unit volume correlated positively with bedding density, while absorbency per unit mass correlated negatively. Therefore, the relative absorbencies of the beddings were almost completely reversed depending on how absorbency was calculated. By volume, corncob was the most absorbent bedding, absorbing about twice as much saline as Tek-Fresh, the least absorbent bedding. Conversely, when calculated by mass, Tek-Fresh appeared to absorb almost three times as much saline as the corncob. Thus, in practical terms the most absorbent bedding here was corncob, followed by the loose pulp beddings; and this is generally supported by their relatively low ammonia production as seen in previous studies. Many factors other than absorbency determine whether a material is suitable as a rodent bedding, and they are briefly mentioned here. However, manufacturers should provide details of bedding absorbencies in terms of volume, in order to help predict the relative absorbencies of the beddings in practical situations.

  9. An ultrathin dual-band metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Duan, Junping; Zhang, Wendong; Wang, Wanjun; Zhang, Binzhen

    2016-10-01

    The design and preparation of an ultrathin dual-band metamaterial absorber whose resonant frequency located at radar wave (20 GHz-60 GHz) is presented in this paper. The absorber is composed of a 2-D periodic sandwich featured with two concentric annuluses. The influence on the absorber's performance produced by resonant cell's structure size and material parameters was numerically simulated and analyzed based on the standard full wave finite integration technology in CST. Laser ablation process was adopted to prepare the designed absorber on epoxy resin board coated with on double plane of copper with a thickness that is 1/30 and 1/50 of the resonant wavelength at a resonant frequency of 30.51 GHz and 48.15 GHz. The full width at half maximum (FWHM) reached 2.2 GHz and 2.35 GHz and the peak of the absorptance reached 99.977%. The ultrathin absorber is nearly omnidirectional for all polarizations. The test results of prepared sample testify the designed absorber's excellent absorbing performance forcefully. The absorber expands inspirations of radar stealth in military domain due to its flexible design, cost-effective and other outstanding properties.

  10. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A...

  11. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A...

  12. Linear motion device and method for inserting and withdrawing control rods

    DOEpatents

    Smith, Jay E.

    1984-01-01

    A linear motion device, more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core, is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.

  13. 77 FR 3231 - Certain Stainless Steel Wire Rods From India: Continuation of Antidumping Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-23

    ... Stainless Steel Wire Rods From India: Continuation of Antidumping Duty Order AGENCY: Import Administration... antidumping duty order on certain stainless steel wire rods from India would likely lead to continuation or... reviews of the antidumping duty order on certain stainless steel wire rods (``wire rods'') from...

  14. 78 FR 12718 - Certain Steel Threaded Rod From the People's Republic of China: Affirmative Final Determination...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... International Trade Administration Certain Steel Threaded Rod From the People's Republic of China: Affirmative... concerning the antidumping duty order on certain steel threaded rod (``steel threaded rod'') from the People.... No other party filed comments. \\1\\ See Certain Steel Threaded Rod From the People's Republic of...

  15. AN INTRODUCTION TO THE CUISENAIRE RODS, AN APPROACH TO THE TEACHING OF ELEMENTARY MATHEMATICS.

    ERIC Educational Resources Information Center

    HULL, WILLIAM P.

    CUISENAIRE RODS ARE COLORED, RECTANGULAR PIECES OF WOOD ONE UNIT WIDE AND ANY NUMBER OF UNITS LONG. THE COLOR OF THE ROD DEPENDS UPON ITS LENGTH. RODS CAN BE USED IN KINDERGARTEN THROUGH HIGH SCHOOL, BUT ARE PARTICULARILY HELPFUL IN THE EARLY GRADES. THE RODS CAN BE USED TO TEACH CHILDREN SUCH CONCEPTS AS…

  16. [Absorbed doses in dental radiology].

    PubMed

    Bianchi, S D; Roccuzzo, M; Albrito, F; Ragona, R; Anglesio, S

    1996-01-01

    The growing use of dento-maxillo-facial radiographic examinations has been accompanied by the publication of a large number of studies on dosimetry. A thorough review of the literature is presented in this article. Most studies were carried out on tissue equivalent skull phantoms, while only a few were in vivo. The aim of the present study was to evaluate in vivo absorbed doses during Orthopantomography (OPT). Full Mouth Periapical Examination (FMPE) and Intraoral Tube Panoramic Radiography (ITPR). Measurements were made on 30 patients, reproducing clinical conditions, in 46 anatomical sites, with 24 intra- and 22 extra-oral thermoluminiscent dosimeters (TLDS). The highest doses were measured, in orthopantomography, at the right mandibular angle (1899 mu Gy) in FMPE on the right naso-labial fold (5640 mu Gy and in ITPR on the palatal surface of the left second upper molar (1936 mu Gy). Intraoral doses ranged from 21 mu Gy, in orthopantomography, to 4494 mu Gy in FMPE. Standard errors ranged from 142% in ITPR to 5% in orthopantomography. The highest rate of standard errors was found in FMPE and ITPR. The data collected in this trial are in agreement with others in major literature reports. Disagreements are probably due to different exam acquisition and data collections. Such differences, presented comparison in several sites, justify lower doses in FMPE and ITPR. Advantages and disadvantages of in vivo dosimetry of the maxillary region are discussed, the former being a close resemblance to clinical conditions of examination and the latter the impossibility of collecting values in depth of tissues. Finally, both ITPR and FMPE required lower doses than expected, and can be therefore reconsidered relative to their radiation risk.

  17. A Multi-Stage Wear Model for Grid-to-Rod Fretting of Nuclear Fuel Rods

    SciTech Connect

    Blau, Peter Julian

    2014-01-01

    The wear of fuel rod cladding against the supporting structures in the cores of pressurized water nuclear reactors (PWRs) is an important and potentially costly tribological issue. Grid-to-rod fretting (GTRF), as it is known, involves not only time-varying contact conditions, but also elevated temperatures, flowing hot water, aqueous tribo-corrosion, and the embrittling effects of neutron fluences. The multi-stage, closed-form analytical model described in this paper relies on published out-of-reactor wear and corrosion data and a set of simplifying assumptions to portray the conversion of frictional work into wear depth. The cladding material of interest is a zirconium-based alloy called Zircaloy-4, and the grid support is made of a harder and more wear-resistant material. Focus is on the wear of the cladding. The model involves an incubation stage, a surface oxide wear stage, and a base alloy wear stage. The wear coefficient, which is a measure of the efficiency of conversion of frictional work into wear damage, can change to reflect the evolving metallurgical condition of the alloy. Wear coefficients for Zircaloy-4 and for a polyphase zirconia layer were back-calculated for a range of times required to wear to a critical depth. Inputs for the model, like the friction coefficient, are taken from the tribology literature in lieu of in-reactor tribological data. Concepts of classical fretting were used as a basis, but are modified to enable the model to accommodate the complexities of the PWR environment. Factors like grid spring relaxation, pre-oxidation of the cladding, multiple oxide phases, gap formation, impact, and hydrogen embrittlement are part of the problem definition but uncertainties in their relative roles limits the ability to validate the model. Sample calculations of wear depth versus time in the cladding illustrate how GTRF wear might occur in a discontinuous fashion during months-long reactor operating cycles. A means to account for grid/rod gaps

  18. Design of a nonlinear torsional vibration absorber

    NASA Astrophysics Data System (ADS)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  19. Detection of single photons by toad and mouse rods.

    PubMed

    Reingruber, Jürgen; Pahlberg, Johan; Woodruff, Michael L; Sampath, Alapakkam P; Fain, Gordon L; Holcman, David

    2013-11-26

    Amphibian and mammalian rods can both detect single photons of light even though they differ greatly in physical dimensions, mammalian rods being much smaller in diameter than amphibian rods. To understand the changes in physiology and biochemistry required by such large differences in outer segment geometry, we developed a computational approach, taking into account the spatial organization of the outer segment divided into compartments, together with molecular dynamics simulations of the signaling cascade. We generated simulations of the single-photon response together with intrinsic background fluctuations in toad and mouse rods. Combining this computational approach with electrophysiological data from mouse rods, we determined key biochemical parameters. On average around one phosphodiesterase (PDE) molecule is spontaneously active per mouse compartment, similar to the value for toad, which is unexpected due to the much smaller diameter in mouse. A larger number of spontaneously active PDEs decreases dark noise, thereby improving detection of single photons; it also increases cGMP turnover, which accelerates the decay of the light response. These constraints explain the higher PDE density in mammalian compared with amphibian rods that compensates for the much smaller diameter of mammalian disks. We further find that the rate of cGMP hydrolysis by light-activated PDE is diffusion limited, which is not the case for spontaneously activated PDE. As a consequence, in the small outer segment of a mouse rod only a few activated PDEs are sufficient to generate a signal that overcomes noise, which permits a shorter lifetime of activated rhodopsin and greater temporal resolution.

  20. Estimation of rod scale errors in geodetic leveling

    USGS Publications Warehouse

    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.

  1. Rod/Coil Block Copolyimides for Ion-Conducting Membranes

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Kinder, James D.

    2003-01-01

    Rod/coil block copolyimides that exhibit high levels of ionic conduction can be made into diverse products, including dimensionally stable solid electrolyte membranes that function well over wide temperature ranges in fuel cells and in lithium-ion electrochemical cells. These rod/coil block copolyimides were invented to overcome the limitations of polymers now used to make such membranes. They could also be useful in other electrochemical and perhaps some optical applications, as described below. The membranes of amorphous polyethylene oxide (PEO) now used in lithium-ion cells have acceptably large ionic conductivities only at temperatures above 60 C, precluding use in what would otherwise be many potential applications at lower temperatures. PEO is difficult to process, and, except at the highest molecular weights it is not very dimensionally stable. It would be desirable to operate fuel cells at temperatures above 80 C to take advantage of better kinetics of redox reactions and to reduce contamination of catalysts. Unfortunately, proton-conduction performance of a typical perfluorosulfonic polymer membrane now used as a solid electrolyte in a fuel cell decreases with increasing temperature above 80 C because of loss of water from within the membrane. The loss of water has been attributed to the hydrophobic nature of the polymer backbone. In addition, perfluorosulfonic polymers are expensive and are not sufficiently stable for long-term use. Rod/coil block copolyimides are so named because each molecule of such a polymer comprises short polyimide rod segments alternating with flexible polyether coil segments (see figure). The rods and coils can be linear, branched, or mixtures of linear and branched. A unique feature of these polymers is that the rods and coils are highly incompatible, giving rise to a phase separation with a high degree of ordering that creates nanoscale channels in which ions can travel freely. The conduction of ions can occur in the coil phase

  2. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G.

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  3. Strategy for Fuel Rod Receipt, Characterization, Sample Allocation for the Demonstration Sister Rods

    SciTech Connect

    Marschman, Steven C.; Warmann, Stephan A.; Rusch, Chris

    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.

  4. The nonlinear piezoelectric tuned vibration absorber

    NASA Astrophysics Data System (ADS)

    Soltani, P.; Kerschen, G.

    2015-07-01

    This paper proposes a piezoelectric vibration absorber, termed the nonlinear piezoelectric tuned vibration absorber (NPTVA), for the mitigation of nonlinear resonances of mechanical systems. The new feature of the NPTVA is that its nonlinear restoring force is designed according to a principle of similarity, i.e., the NPTVA should be an electrical analog of the nonlinear host system. Analytical formulas for the NPTVA parameters are derived using the homotopy perturbation method. Doing so, a nonlinear generalization of Den Hartog’s equal-peak tuning rule is developed for piezoelectric vibration absorbers.

  5. Circadian and light-driven regulation of rod dark adaptation.

    PubMed

    Xue, Yunlu; Shen, Susan Q; Corbo, Joseph C; Kefalov, Vladimir J

    2015-12-02

    Continuous visual perception and the dark adaptation of vertebrate photoreceptors after bright light exposure require recycling of their visual chromophore through a series of reactions in the retinal pigmented epithelium (RPE visual cycle). Light-driven chromophore consumption by photoreceptors is greater in daytime vs. nighttime, suggesting that correspondingly higher activity of the visual cycle may be required. However, as rod photoreceptors are saturated in bright light, the continuous turnover of their chromophore by the visual cycle throughout the day would not contribute to vision. Whether the recycling of chromophore that drives rod dark adaptation is regulated by the circadian clock and light exposure is unknown. Here, we demonstrate that mouse rod dark adaptation is slower during the day or after light pre-exposure. This surprising daytime suppression of the RPE visual cycle was accompanied by light-driven reduction in expression of Rpe65, a key enzyme of the RPE visual cycle. Notably, only rods in melatonin-proficient mice were affected by this daily visual cycle modulation. Our results demonstrate that the circadian clock and light exposure regulate the recycling of chromophore in the RPE visual cycle. This daily melatonin-driven modulation of rod dark adaptation could potentially protect the retina from light-induced damage during the day.

  6. Braided reinforced composite rods for the internal reinforcement of concrete

    NASA Astrophysics Data System (ADS)

    Gonilho Pereira, C.; Fangueiro, R.; Jalali, S.; Araujo, M.; Marques, P.

    2008-05-01

    This paper reports on the development of braided reinforced composite rods as a substitute for the steel reinforcement in concrete. The research work aims at understanding the mechanical behaviour of core-reinforced braided fabrics and braided reinforced composite rods, namely concerning the influence of the braiding angle, the type of core reinforcement fibre, and preloading and postloading conditions. The core-reinforced braided fabrics were made from polyester fibres for producing braided structures, and E-glass, carbon, HT polyethylene, and sisal fibres were used for the core reinforcement. The braided reinforced composite rods were obtained by impregnating the core-reinforced braided fabric with a vinyl ester resin. The preloading of the core-reinforced braided fabrics and the postloading of the braided reinforced composite rods were performed in three and two stages, respectively. The results of tensile tests carried out on different samples of core-reinforced braided fabrics are presented and discussed. The tensile and bending properties of the braided reinforced composite rods have been evaluated, and the results obtained are presented, discussed, and compared with those of conventional materials, such as steel.

  7. Nano-rods of zinc oxide in nano-graphene

    NASA Astrophysics Data System (ADS)

    Ortiz, Pedro; Chavira, Elizabeth; Monroy, Marel; Elizalde, José; Santiago, Patricia; Sato, Roberto; Tejeda, Adriana; González, Guillermina; Novelo, Omar; Flores, Carlos

    2014-03-01

    It's of great interest to study the devices based on nano-ZnO and graphene, for their electromagnetic and optical properties to increase the efficiency of solar cells. The graphene multilayers synthesis was done by mechanosynthesis, grinding in a mechanical agate mortar. The zinc oxide nano-rods were synthesized from zinc acetate dihydrate, Ace, (Sigma Aldrich) and ethylene diamine, En, (Sigma Aldrich) with a 1:2 ratio of reagents En/Ace. The ZnO nano-rods in nano-tubes graphene were obtained by mechanosynthesis. The X-ray powder diffraction, shows the shift of C with PDF 12-0212 and ZnO, Zincite PDF 36-1451, both with hexagonal unit cell. The grain size and morphology of graphene (multilayers and nano-tubes), ZnO nano-rods and ZnO-graphene mixture (multilayers, nano-tubes) were observed by scanning electron microscope. Transmission electron microscope, corroborates shown in SEM. Raman spectroscopy, shows the shift of multilayer graphene and the ZnO nano-rods. In photoluminescence measurements, observe the change in intensity in the band defects. Magnetic properties characterization was carried out by Vibrating Sample Magnetometry. We conclude that graphite multilayers dislocated by cutting efforts, forming graphene nano-tubes and encapsulated ZnO nano-rods within graphene.

  8. Circadian and light-driven regulation of rod dark adaptation

    PubMed Central

    Xue, Yunlu; Shen, Susan Q.; Corbo, Joseph C.; Kefalov, Vladimir J.

    2015-01-01

    Continuous visual perception and the dark adaptation of vertebrate photoreceptors after bright light exposure require recycling of their visual chromophore through a series of reactions in the retinal pigmented epithelium (RPE visual cycle). Light-driven chromophore consumption by photoreceptors is greater in daytime vs. nighttime, suggesting that correspondingly higher activity of the visual cycle may be required. However, as rod photoreceptors are saturated in bright light, the continuous turnover of their chromophore by the visual cycle throughout the day would not contribute to vision. Whether the recycling of chromophore that drives rod dark adaptation is regulated by the circadian clock and light exposure is unknown. Here, we demonstrate that mouse rod dark adaptation is slower during the day or after light pre-exposure. This surprising daytime suppression of the RPE visual cycle was accompanied by light-driven reduction in expression of Rpe65, a key enzyme of the RPE visual cycle. Notably, only rods in melatonin-proficient mice were affected by this daily visual cycle modulation. Our results demonstrate that the circadian clock and light exposure regulate the recycling of chromophore in the RPE visual cycle. This daily melatonin-driven modulation of rod dark adaptation could potentially protect the retina from light-induced damage during the day. PMID:26626567

  9. Quasi-static and dynamic response of viscoelastic helical rods

    NASA Astrophysics Data System (ADS)

    Temel, Beytullah; Fırat Çalim, Faruk; Tütüncü, Naki

    2004-04-01

    In this study, the dynamic behaviour of cylindrical helical rods made of linear viscoelastic materials are investigated in the Laplace domain. The governing equations for naturally twisted and curved spatial rods obtained using the Timoshenko beam theory are rewritten for cylindrical helical rods. The curvature of the rod axis, effect of rotary inertia, and shear and axial deformations are considered in the formulation. The material of the rod is assumed to be homogeneous, isotropic and linear viscoelastic. In the viscoelastic material case, according to the correspondence principle, the material constants are replaced with their complex counterparts in the Laplace domain. Ordinary differential equations in scalar form obtained in the Laplace domain are solved numerically using the complementary functions method to calculate the dynamic stiffness matrix of the problem. In the solutions, the Kelvin model is employed. The solutions obtained are transformed to the real space using the Durbin's numerical inverse Laplace transform method. Numerical results for quasi-static and dynamic response of viscoelastic models are presented in the form of graphics.

  10. Failure kinetics in borosilicate glass during rod impact

    SciTech Connect

    Orphal, Dennis L.; Anderson, Charles E. Jr.; Behner, Thilo; Hohler, Volker; Wickert, Matthias; Templeton, Douglas W.

    2007-12-12

    Failure front (FF) and penetration velocity have been measured for long gold rods impacting and penetrating borosilicate (BS) glass. Data are obtained by visualizing simultaneously FF propagation with a high speed camera and rod penetration with flash X-rays. Results for BS glass are qualitatively similar to those of DEDF (PbO) glass. FF velocity rapidly decreases from an initial value to a lower, approximately constant value. FF velocity increases with impact velocity, v{sub p}. The FF velocity remains significantly lower than the shear velocity, even at the highest impact velocity tested, about 2.5 km/s. The ratio of the FF velocity to the rod penetration velocity, v{sub F}/u, decreases with increasing v{sub p} and appears to be approaching v{sub F}/u = 1 asymptotically, as observed previously for DEDF glass. The separation of the FF and the tip of the rod decreases with increasing impact velocity. Importantly, since v{sub F}/u{>=}1, the gold rod is always penetrating glass behind the FF.

  11. Fault pseudotachylyte: a coseismic lightning rod

    NASA Astrophysics Data System (ADS)

    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. Attenuation of external Bremsstrahlung in metallic absorbers

    SciTech Connect

    Dhaliwal, A.S.; Powar, M.S.; Singh, M. )

    1990-12-01

    In this paper attenuation of bremsstrahlung from {sup 147}Pm and {sup 170}Tm beta emitters has been studied in aluminum, copper, tin, and lead metallic absorbers. Bremsstrahlung spectra and mass attenuation coefficients for monoenergetic gamma rays are used to calculate theoretical attenuation curves. Magnetic deflection and beta stopping techniques are used to measure the integral bremsstrahlung intensities above 30 keV in different target thicknesses. Comparison of measured and calculated attenuation curves shows a good agreement for various absorbers, thus providing a test of this technique, which may be useful in understanding bremsstrahlung intensity buildup and in the design of optimum shielding for bremsstrahlung sources. It is found that the absorption of bremsstrahlung in metallic absorbers does not obey an exponential law and that absorbers act as energy filters.

  13. Energy absorber uses expanded coiled tube

    NASA Technical Reports Server (NTRS)

    Johnson, E. F.

    1972-01-01

    Mechanical shock mitigating device, based on working material to its failure point, absorbs mechanical energy by bending or twisting tubing. It functions under axial or tangential loading, has no rebound, is area independent, and is easy and inexpensive to build.

  14. Neutron absorbing coating for nuclear criticality control

    DOEpatents

    Mizia, Ronald E.; Wright, Richard N.; Swank, William D.; Lister, Tedd E.; Pinhero, Patrick J.

    2007-10-23

    A neutron absorbing coating for use on a substrate, and which provides nuclear criticality control is described and which includes a nickel, chromium, molybdenum, and gadolinium alloy having less than about 5% boron, by weight.

  15. Durability of Polymeric Glazing and Absorber Materials

    SciTech Connect

    Jorgensen, G.; Terwilliger, K.; Bingham, C.; Milbourne, M.

    2005-01-01

    The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. The objective of this task is to quantify lifetimes through measurement of the optical and mechanical stability of candidate polymeric glazing and absorber materials. Polycarbonate sheet glazings, as proposed by two industry partners, have been tested for resistance to UV radiation with three complementary methods. Incorporation of a specific 2-mil thick UV-absorbing screening layer results in glazing lifetimes of at least 15 years; improved screens promise even longer lifetimes. Proposed absorber materials were tested for creep and embrittlement under high temperature, and appear adequate for planned ICS absorbers.

  16. Porous absorber for solar air heaters

    SciTech Connect

    Finch, J.A.

    1980-09-10

    A general discussion of the factors affecting solar collector performance is presented. Bench scale tests done to try to determine the heat transfer characteristics of various screen materials are explained. The design, performance, and evaluation of a crude collector with a simple screen stack absorber is treated. The more sophisticated absorber concept, and its first experimental approximation is examined. A short summary of future plans for the collector concept is included. (MHR)

  17. Multilayer Radar Absorbing Non-Woven Material

    NASA Astrophysics Data System (ADS)

    Dedov, A. V.; Nazarov, V. G.

    2016-06-01

    We study the electrical properties of multilayer radar absorbing materials obtained by adding nonwoven sheets of dielectric fibers with an intermediate layer of electrically conductive carbon fibers. Multilayer materials that absorb electromagnetic radiation in a wide frequency range are obtained by varying the content of the carbon fibers. The carbon-fiber content dependent mechanism of absorption of electromagnetic radiation by sheets and multilayer materials is considered.

  18. Non-absorbed Antibiotics for IBS

    DTIC Science & Technology

    2012-03-16

    absorbed antibiotic rifaximin for nonconstipated irritable bowel syndrome (IBS). This effort adds to the body of literature from other, smaller studies that...have demonstrated clinical efficacy for IBS with rifaximin . Non-absorbed antibiotics have been endorsed by the American College of Gastroenterology... rifaximin 400 mg three times daily for 10 days or placebo. During the initial 2 weeks of therapy and the subsequent 10 weeks of follow-up rifaximin

  19. Structured metal film as a perfect absorber.

    PubMed

    Xiong, Xiang; Jiang, Shang-Chi; Hu, Yu-Hui; Peng, Ru-Wen; Wang, Mu

    2013-08-07

    A new type of absorber, a four-tined fish-spear-like resonator (FFR), constructed by the two-photon polymerization process, is reported. An absorbance of more than 90% is experimentally realized and the resonance occurs in the space between the tines. Since a continuous layer of metallic thin film covers the structure, it is perfectly thermo- and electroconductive, which is the mostly desired feature for many applications.

  20. Tensile Characterization of FRP Rods for Reinforced Concrete Structures

    NASA Astrophysics Data System (ADS)

    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.

  1. Prominent 946 lines induced from flashlamp pumped Nd: YAG rod

    NASA Astrophysics Data System (ADS)

    Bidin, Noriah; Zainal, Roslinda; Daud, Yaacob Mat; Pourmand, Seyed Ebrahim; Bakhtiar, Hazri

    2012-06-01

    Spectroscopic properties of Nd:YAG laser rod pumped by a new developed flashlamp is investigated. A new power supply is constructed to power xenon flashlamp. A 1 at.% Nd:YAG laser rod is transversely pumped by the flashlamp and stabilized by a water cooling system operated at ambient temperature of 20°C. The absorption and emission spectrum of the flashlamp pumped Nd:YAG rod is analyzed via spectroscopy technique. The peak absorption line is identified to be at 882 nm. The dominant emission line obtained from transition 4F3/2→4I9/2 comprised of quasi three level laser at 938.5 and 946 nm with the corresponding cross section of 2.42×10-19cm2 and 3.04×10-19cm2 respectively. This cross section is found almost ten times greater than the usual one.

  2. Noise Radiation from Single and Multiple Rod Configurations

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Brooks, Thomas F.

    2006-01-01

    Acoustic measurements were performed on single and multiple rod configurations to study the effect of Reynolds number, surface roughness, freestream turbulence, proximity and wake interference on the radiated noise. The Reynolds number ranged from 3.8 x 10(exp 3) to 10(exp 5). Directivity measurements were performed to determine how well the dipole assumption for the radiation of vortex shedding noise holds for the different model configurations tested. The dependence of the peak Sound Pressure Level on velocity was also examined. Several concepts for the reduction of the noise radiating from cylindrical rods were tested. It was shown that wire wraps and collar distributions could be used to significantly reduce the noise radiating from rods in tandem configurations.

  3. Dynamic features of rod-shaped Au nanoclusters

    NASA Astrophysics Data System (ADS)

    So, Woong Young; Das, Anindita; Wang, Shuxin; Zhao, Shuo; Byun, Hee Young; Lee, Dana; Kumar, Santosh; Jin, Rongchao; Peteanu, Linda A.

    2015-08-01

    Gold nanoclusters hold many potential applications such as biosensing and optics due to their emission characteristics, small size, and non-toxicity. However, their low quantum yields remain problematic for further applications, and their fluorescence mechanism is still unclear. To increase the low quantum yields, various methods have been performed: doping, tuning structures, and changing number of gold atoms. In the past, most characterizations have been performed on spherical shaped nanoclusters; in this paper, several characterizations of various rod-shaped Au nanoclusters specifically on Au25 are shown. It has been determined that the central gold atom in Au25 nano-rod is crucial in fluorescence. Furthermore, single molecule analysis of silver doped Au25 nano-rod revealed that it has more photo-stability than conjugated polymers and quantum dots.

  4. Characterisation of Plasma Filled Rod Pinch electron beam diode operation

    NASA Astrophysics Data System (ADS)

    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.

  5. Plasmonic-cavity model for radiating nano-rod antennas.

    PubMed

    Peng, Liang; Mortensen, N Asger

    2014-01-23

    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.

  6. Protons block the dark current of isolated retinal rods.

    PubMed

    Mueller, P; Pugh, E N

    1983-04-01

    Membrane currents of isolated frog rods were recorded with the suction pipette technique and tested by perfusion techniques for their sensitivity to H+. The following facts have been established. (i) Increased [H+] suppresses the Na+ conductance of the outer segment rapidly and reversibly. (ii) H+ acts in the rod interior. (iii) The [H+] necessary to cause a 50% decrement in Na+ conductance is inversely related to the [Ca2+] over 5 orders of magnitude. (iv) The sensitivity to H+ and the sensitivity to light, as a function of [Ca2+], have the same slope. Thus, H+ act like light in effecting membrane current suppression but behave as if their effect is mediated through Ca2+. Based on these results and properties of rod disk membrane phosphodiesterase, we propose that protons produced in the light-activated hydrolysis of cGMP liberate Ca2+ from the disks by ion exchange.

  7. Radar Absorbing Materials for Cube Stealth Satellite

    NASA Astrophysics Data System (ADS)

    Micheli, D.; Pastore, R.; Vricella, A.; Marchetti, M.

    A Cube Stealth Satellite is proposed for potential applications in defense system. Particularly, the faces of the satellite exposed to the Earth are made of nanostructured materials able to absorb radar surveillance electromagnetic waves, conferring stealth capability to the cube satellite. Microwave absorbing and shielding material tiles are proposed using composite materials consisting in epoxy-resin and carbon nanotubes filler. The electric permittivity of the composite nanostructured materials is measured and discussed. Such data are used by the modeling algorithm to design the microwave absorbing and the shielding faces of the cube satellite. The electromagnetic modeling takes into account for several incidence angles (0-80°), extended frequency band (2-18 GHz), and for the minimization of the electromagnetic reflection coefficient. The evolutionary algorithm used for microwave layered microwave absorber modeling is the recently developed Winning Particle Optimization. The mathematical model of the absorbing structure is finally experimentally validated by comparing the electromagnetic simulation to the measurement of the manufactured radar absorber tile. Nanostructured composite materials manufacturing process and electromagnetic reflection measurements methods are described. Finally, a finite element method analysis of the electromagnetic scattering by cube stealth satellite is performed.

  8. Absorbance changes of carotenoids in different solvents.

    PubMed

    Zang, L Y; Sommerburg, O; van Kuijk, F J

    1997-01-01

    Carotenoids are typically measured in tissues with the high performance liquid chromatography (HPLC) and quantitation is usually done by calibrating with stock solutions in solvents. Four carotenoids including lutein, zeaxanthin, lycopene and beta-carotene were dissolved in hexane and methanol respectively, and their absorbance characteristics were compared. Lutein shows absorbance spectra that are almost independent of solvents at various concentrations. Spectra of zeaxanthin, lycopene and beta-carotene were found to be more solvent-dependent. The absorbance of zeaxanthin at lambda max is about approximately 2 times larger in methanol than in hexane at the higher concentrations, and increased non-linearly with increasing concentration in hexane. The absorbance of lycopene at lambda max in hexane is approximately 4 fold larger than in methanol, but the absorbance of the methanol sample can be recovered by re-extracting this sample in hexane. The absorbance of beta-carotene in hexane is larger than in methanol, and increased linearly with increasing concentration. But beta-carotene showed a non-linear concentration effect in methanol. There are very small variations in lambda max for all four carotenoids between hexane and methanol, due to differences in molar extinction coefficients. The non-linear concentration effects for these carotenoids are probably due to differences in solubility leading to the formation of microcrystals. Thus, care should be taken with quantitation of tissue carotenoid values, when they depend on measurement of concentrations in stock solutions.

  9. Perfect terahertz absorber using fishnet based metafilm

    SciTech Connect

    Azad, Abul Kalam; Shchegolkov, Dmitry Yu; Chen, Houtong; Taylor, Antoinette; Smirnova, E I; O' Hara, John F

    2009-01-01

    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  10. Nuclear Data Library Effects on Fast to Thermal Flux Shapes Around PWR Control Rod Tips

    NASA Astrophysics Data System (ADS)

    Vasiliev, A.; Ferroukhi, H.; Zhu, T.; Pautz, A.

    2014-04-01

    The development of a high-fidelity computational scheme to estimate the accumulated fluence at the tips of PWR control rods (CR) has been initiated at the Paul Scherrer Institut (PSI). Both the fluence from high-energy (E>1 MeV) neutrons as well as for the thermal range (E<0.625 eV) are required as these affect the CR integrity through stresses/strains induced by coupled clad embrittlement / absorber swelling phenomena. The concept of the PSI scheme under development is to provide from validated core analysis models, the volumetric neutron source to a full core MCNPX model that is then used to compute the neutron fluxes. A particular aspect that needs scrutiny is the ability of the MCNPX-based calculation methodology to accurately predict the flux shapes along the control rod surfaces, especially for fully withdrawn CRs. In that case, the tip is located a short distance above the core/reflector interface and since this situation corresponds to a large part of reactor operation, the accumulated fluence will highly depend on the achieved calculation accuracy and precision in this non-fueled zone. The objective of the work presented in this paper is to quantify the influence of nuclear data on the calculated fluxes at the CR tips by (1) conducting a systematic comparison of modern neutron cross-section libraries, including JENDL-4.0, JEFF-3.1.1 and ENDF/B-VII.0, and (2) by quantifying the uncertainties in the neutron flux calculations with the help of available neutron cross-section variances/covariances data. For completeness, the magnitude of these nuclear data-based uncertainties is also assessed in relation to the influence from other typical sources of modeling uncertainties/biases.

  11. Adaptive potentiation in rod photoreceptors after light exposure.

    PubMed

    McKeown, Alex S; Kraft, Timothy W

    2014-06-01

    Photoreceptors adapt to changes in illumination by altering transduction kinetics and sensitivity, thereby extending their working range. We describe a previously unknown form of rod photoreceptor adaptation in wild-type (WT) mice that manifests as a potentiation of the light response after periods of conditioning light exposure. We characterize the stimulus conditions that evoke this graded hypersensitivity and examine the molecular mechanisms of adaptation underlying the phenomenon. After exposure to periods of saturating illumination, rods show a 10-35% increase in circulating dark current, an adaptive potentiation (AP) to light exposure. This potentiation grows as exposure to light is extended up to 3 min and decreases with longer exposures. Cells return to their initial dark-adapted sensitivity with a time constant of recovery of ∼7 s. Halving the extracellular Mg concentration prolongs the adaptation, increasing the time constant of recovery to 13.3 s, but does not affect the magnitude of potentiation. In rods lacking guanylate cyclase activating proteins 1 and 2 (GCAP(-/-)), AP is more than doubled compared with WT rods, and halving the extracellular Mg concentration does not affect the recovery time constant. Rods from a mouse expressing cyclic nucleotide-gated channels incapable of binding calmodulin also showed a marked increase in the amplitude of AP. Application of an insulin-like growth factor-1 receptor (IGF-1R) kinase inhibitor (Tyrphostin AG1024) blocked AP, whereas application of an insulin receptor kinase inhibitor (HNMPA(AM)3) failed to do so. A broad-acting tyrosine phosphatase inhibitor (orthovanadate) also blocked AP. Our findings identify a unique form of adaptation in photoreceptors, so that they show transient hypersensitivity to light, and are consistent with a model in which light history, acting via the IGF-1R, can increase the sensitivity of rod photoreceptors, whereas the photocurrent overshoot is regulated by Ca-calmodulin and Ca(2

  12. Stability and failure analysis of steering tie-rod

    NASA Astrophysics Data System (ADS)

    Jiang, GongFeng; Zhang, YiLiang; Xu, XueDong; Ding, DaWei

    2008-11-01

    A new car in operation of only 8,000 km, because of malfunction, resulting in lost control and rammed into the edge of the road, and then the basic vehicle scrapped. According to the investigation of the site, it was found that the tie-rod of the car had been broken. For the subjective analysis of the accident and identifying the true causes of rupture of the tierod, a series of studies, from the angle of theory to experiment on the bended broken tie-rod, were conducted. The mechanical model was established; the stability of the defective tie-rod was simulated based on ANSYS software. Meanwhile, the process of the accident was simulated considering the effect of destabilization of different vehicle speed and direction of the impact. Simultaneously, macro graphic test, chemical composition analysis, microstructure analysis and SEM analysis of the fracture were implemented. The results showed that: 1) the toughness of the tie-rod is at a normal level, but there is some previous flaws. One quarter of the fracture surface has been cracked before the accident. However, there is no relationship between the flaw and this incident. The direct cause is the dynamic instability leading to the large deformation of impact loading. 2) The declining safety factor of the tie-rod greatly due to the previous flaws; the result of numerical simulation shows that previous flaw is the vital factor of structure instability, on the basis of the comparison of critical loads of the accident tie-rod and normal. The critical load can decrease by 51.3% when the initial defect increases 19.54% on the cross-sectional area, which meets the Theory of Koiter.

  13. Lightweight piston-rod assembly for a reciprocating machine

    DOEpatents

    Corey, John A.; Walsh, Michael M.

    1986-01-01

    In a reciprocating machine, there is provided a hollow piston including a dome portion on one end and a base portion on the opposite end. The base portion includes a central bore into which a rod is hermetically fixed in radial and angular alignment. The extending end of the rod has a reduced diameter portion adapted to fit into the central bore of a second member such as a cross-head assembly, and to be secured thereto in radial and axial alignment with the piston.

  14. Additional information for impact response of the restart safety rods

    SciTech Connect

    Yau, W.W.F.

    1991-10-14

    WSRC-RP-91-677 studied the structural response of the safety rods under the conditions of brake failure and accidental release. It was concluded that the maximum impact loading to the safety rod is 6020 pounds based on conservative considerations that energy dissipation attributable to fluid resistance and reactor superstructure flexibility. The staffers of the Defense Nuclear Facility Safety Board reviewed the results and inquired about the extent of conservatism. By request of the RESTART team, I reassessed the impact force due to these conservative assumptions. This memorandum reports these assessments.

  15. Dendrites of rod bipolar cells sprout in normal aging retina.

    PubMed

    Liets, Lauren C; Eliasieh, Kasra; van der List, Deborah A; Chalupa, Leo M

    2006-08-08

    The aging nervous system is known to manifest a variety of degenerative and regressive events. Here we report the unexpected growth of dendrites in the retinas of normal old mice. The dendrites of many rod bipolar cells in aging mice were observed to extend well beyond their normal strata within the outer plexiform layer to innervate the outer nuclear layer where they appeared to form contacts with the spherules of rod photoreceptors. Such dendritic sprouting increased with age and was evident at all retinal eccentricities. These results provide evidence of retinal plasticity associated with normal aging.

  16. Gene expression changes during retinal development and rod specification

    PubMed Central

    Carrigan, Matthew; Hokamp, Karsten; Farrar, G. Jane

    2015-01-01

    Purpose Retinitis pigmentosa (RP) typically results from individual mutations in any one of >70 genes that cause rod photoreceptor cells to degenerate prematurely, eventually resulting in blindness. Gene therapies targeting individual RP genes have shown efficacy at clinical trial; however, these therapies require the surviving photoreceptor cells to be viable and functional, and may be economically feasible for only the more commonly mutated genes. An alternative potential treatment strategy, particularly for late stage disease, may involve stem cell transplants into the photoreceptor layer of the retina. Rod progenitors from postnatal mouse retinas can be transplanted and can form photoreceptors in recipient adult retinas; optimal numbers of transplantable cells are obtained from postnatal day 3–5 (P3–5) retinas. These cells can also be expanded in culture; however, this results in the loss of photoreceptor potential. Gene expression differences between postnatal retinas, cultured retinal progenitor cells (RPCs), and rod photoreceptor precursors were investigated to identify gene expression patterns involved in the specification of rod photoreceptors. Methods Microarrays were used to investigate differences in gene expression between cultured RPCs that have lost photoreceptor potential, P1 retinas, and fresh P5 retinas that contain significant numbers of transplantable photoreceptors. Additionally, fluorescence-activated cell sorting (FACS) sorted Rho-eGFP-expressing rod photoreceptor precursors were compared with Rho-eGFP-negative cells from the same P5 retinas. Differential expression was confirmed with quantitative polymerase chain reaction (q-PCR). Results Analysis of the microarray data sets, including the use of t-distributed stochastic neighbor embedding (t-SNE) to identify expression pattern neighbors of key photoreceptor specific genes, resulted in the identification of 636 genes differentially regulated during rod specification. Forty-four of these

  17. NEUTRONIC REACTOR CONTROL ROD AND METHOD OF FABRICATION

    DOEpatents

    Porembka, S.W. Jr.

    1961-06-27

    A reactor control rod formed from a compacted powder dispersion is patented. The rod consists of titanium sheathed with a cladding alloy. The cladding alloy contains 1.3% to 1.6% by weight of tin, 0.07% to 0.12% by weight of chromium, 0.04% to 0.08% by weight of nickel, 0.09% to 0.16% by weight of iron, carbon not exceeding 0.05%, less than 0.5% by weight of incidental impurities, and the balance zirconium.

  18. 78 FR 76653 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-18

    ... Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and Tobago, and Ukraine... steel ] wire rod from Brazil and the antidumping duty orders on carbon and certain alloy steel wire rod... wire rod from Brazil and the antidumping duty orders on carbon and certain alloy steel wire rod...

  19. Computer simulations to study the effect of adiabatic heating on rod penetration

    SciTech Connect

    Reaugh, J.E.

    1993-08-01

    We use computer simulations to help us understand the experimental observation that depleted uranium (DU) rods penetrate more steel than equal density tungsten alloy (WA) rods, and that this advantage depends on velocity and fineness ratio. Our simulations used thermal softening. Although the DU rods exhibit shear fracture instead, both phenomena result in a loss of hoop strength, and help to keep the projectile residue from interfering with the incoming rod. Our simulations show that rods of DU (or other alloy with strong thermal softening) penetrate more steel than rods of WA (for alloys with little thermal softening), and show velocity and fineness ratio dependencies that are in qualitative agreement with experiment.

  20. Method of absorbance correction in a spectroscopic heating value sensor

    SciTech Connect

    Saveliev, Alexei; Jangale, Vilas Vyankatrao; Zelepouga, Sergeui; Pratapas, John

    2013-09-17

    A method and apparatus for absorbance correction in a spectroscopic heating value sensor in which a reference light intensity measurement is made on a non-absorbing reference fluid, a light intensity measurement is made on a sample fluid, and a measured light absorbance of the sample fluid is determined. A corrective light intensity measurement at a non-absorbing wavelength of the sample fluid is made on the sample fluid from which an absorbance correction factor is determined. The absorbance correction factor is then applied to the measured light absorbance of the sample fluid to arrive at a true or accurate absorbance for the sample fluid.

  1. Warm Absorber Diagnostics of AGN Dynamics

    NASA Astrophysics Data System (ADS)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  2. Water absorbency by wool fibers: Hofmeister effect.

    PubMed

    Lo Nostro, Pierandrea; Fratoni, Laura; Ninham, Barry W; Baglioni, Piero

    2002-01-01

    Wool is a complex material, composed of cuticle and epicuticle cells, surrounded by a cell membrane complex. Wool fibers absorb moisture from air, and, once immersed in water, they take up considerable amounts of liquid. The water absorbency parameter can be determined from weight gain, according to a standard method, and used to quantify this phenomenon. In this paper we report a study on the water absorbency (or retention) of untreated wool fibers in the presence of aqueous 1 M salt solutions at 29 degrees C and a relative humidity of either 33% or 56%. The effect of anions was determined by selecting a wide range of different sodium salts, while the effect of cations was checked through some chlorides and nitrates. Our results show a significant specific ion and ion pair "Hofmeister" effects, that change the amount of water absorbed by the fibers. To understand this phenomenon, the water absorbency parameter (A(w)) is compared to different physicochemical parameters such as the lyotropic number, free energy of hydration of ions, molar surface tension increment, polarizability, refractive index increment, and molar refractivity. The data indicate that this Hofmeister phenomenon is controlled by dispersion forces that depend on the polarizability of ionic species, their adsorption frequencies, the solvent, and the substrate. These dispersion forces dominate the behavior in concentrated solutions. They are in accord with new developing theories of solutions and molecular interactions in colloidal systems that account for Hofmeister effects.

  3. Oxygen absorbers in food preservation: a review.

    PubMed

    Cichello, Simon Angelo

    2015-04-01

    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen impermeable package material and the quality of oxygen absorber. Ferrous iron oxides are the most reliable and commonly used oxygen absorbers within the food industry. Oxygen absorbers have been transformed from sachets of dried iron-powder to simple self-adhesive patches to accommodate any custom size, capacity and application. Oxygen concentration can be effectively lowered to 100 ppm, with applications spanning a wide range of food products and beverages across the world (i.e. bread, meat, fish, fruit, and cheese). Newer molecules that preserve packaged food materials from all forms of degradation are being developed, however oxygen absorbers remain a staple product for the preservation of food and pharmaceutical products to reduce food wastage in developed nations and increased food security in the developing & third world.

  4. VIEW OF EAST GUN EMPLACEMENT. NOTE THE STEEL REINFORCING RODS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF EAST GUN EMPLACEMENT. NOTE THE STEEL REINFORCING RODS PROTRUDING FROM THE BROKEN TOP OF THE RETAINING WALL. VIEW FACING NORTHEAST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, East Gun Emplacement, Ford Island, Pearl City, Honolulu County, HI

  5. Flexible Stabilisation of the Degenerative Lumbar Spine Using PEEK Rods

    PubMed Central

    Benezech, Jacques; Garlenq, Bruno; Larroque, Gilles

    2016-01-01

    Posterior lumbar interbody fusion using cages, titanium rods, and pedicle screws is considered today as the gold standard of surgical treatment of lumbar degenerative disease and has produced satisfying long-term fusion rates. However this rigid material could change the physiological distribution of load at the instrumental and adjacent segments, a main cause of implant failure and adjacent segment disease, responsible for a high rate of further surgery in the following years. More recently, semirigid instrumentation systems using rods made of polyetheretherketone (PEEK) have been introduced. This clinical study of 21 patients focuses on the clinical and radiological outcomes of patients with lumbar degenerative disease treated with Initial VEOS PEEK®-Optima system (Innov'Spine, France) composed of rods made from PEEK-OPTIMA® polymer (Invibio Biomaterial Solutions, UK) without arthrodesis. With an average follow-up of 2 years and half, the chances of reoperation were significantly reduced (4.8%), quality of life was improved (ODI = 16%), and the adjacent disc was preserved in more than 70% of cases. Based on these results, combined with the biomechanical and clinical data already published, PEEK rods systems can be considered as a safe and effective alternative solution to rigid ones. PMID:26981285

  6. INTERFACE DEFEAT OF LONG RODS IMPACTING BOROSILICATE GLASS EXPERIMENTAL RESULTS

    DTIC Science & Technology

    2009-02-01

    UNCLASSIFIED UNCLASSIFIED Interface Defeat of Long Rods Impacting Borosilicate Glass Experimental Results Charles E. Anderson, Jr. Thilo Behner...6. AUTHOR(S) Charles E. Anderson, Jr.1, Thilo Behner2, Dennis L. Orphal3, Timothy J. Holmquist4, Volker Hohler2, , and Matthias Wickert2 5f. WORK

  7. Nonlinear optical properties of rigid-rod polymers

    NASA Technical Reports Server (NTRS)

    Trimmer, Mark S.; Wang, Ying

    1992-01-01

    The purpose of this research project was to integrate enhanced third order nonlinear optical (NLO) properties, especially high x(exp (3)) (greater than 10(exp -8) esu), into Maxdem's novel conjugated rigid-rod polymers while retaining their desirable processing, mechanical, and thermal properties. This work primarily involved synthetic approaches to optimized materials.

  8. Porous tantalum rods for treating osteonecrosis of the femoral head.

    PubMed

    Liu, Z H; Guo, W S; Li, Z R; Cheng, L M; Zhang, Q D; Yue, D B; Shi, Z C; Wang, B L; Sun, W; Zhang, N F

    2014-10-20

    This study evaluated the outcomes of using porous tantalum rods for the treatment of osteonecrosis of the femoral head (ONFH). We performed core decompression and inserted porous tantalum implants in 149 patients (168 consecutive hips) with ONFH. Hips had large (65), medium (64), or small (39) lesions; 63 lesions were lateral, 68 were central, and 35 were medial. Conversion to total hip arthroplasty (THA) was the end point of this survey. A total of 130 cases (138 hips) were followed. The mean follow-up time was 38.46 ± 5.76 months; 43 hips (31%) were converted to or needed THA. Of the 43 hips requiring THA, 33 had large lesions, including 1 medial, 3 central, and 29 lateral lesions; 9 had medium, lateral lesions, and 1 hip had a small, lateral lesion. Bone grafting was used in 59 hips, with 3 hips failing; 40 of 79 hips without bone grafts failed. The sum distances between the tops of the rods and the lateral lesion boundaries (SDTL, mm) were measured in anteroposterior and lateral radiographs. In the failure and spared groups, the average SDTLs were 7.65 ± 2.759 and 0.83 ± 2.286 mm, respectively. The survival of porous tantalum rods used for treating early-stage ONFH was affected by the size and location of the lesion, whether or not a bone graft was used, as well as the distance between top of the rod and the lateral boundary of the lesion.

  9. Fabrication of control rods for the High Flux Isotope Reactor

    SciTech Connect

    Sease, J.D.

    1998-03-01

    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.

  10. 14. Photographic copy of photocopy of bridge drawing, reinforced rod ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Photographic copy of photocopy of bridge drawing, reinforced rod specifications (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 6 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

  11. Mechanized Polishing of Optical Rod and Fiber Ends

    NASA Technical Reports Server (NTRS)

    Gum, J. S.

    1987-01-01

    Workpiece holder for standard grinding and polishing machine makes it easier to produce optical finish and shape on end of metal or glass rod or bundle of optical fibers. Previously, glass parts lapped and polished manually, time-consuming procedure calling for considerable skill.

  12. Second Language Acquisition Research: A Response to Rod Ellis.

    ERIC Educational Resources Information Center

    Hopkins, Diana; Nettle, Mark

    1994-01-01

    Two practicing English-as-a-Foreign-Language (EFL teachers respond to Rod Ellis' January 1993 article in "ELT Journal," which discussed importance of grammar instruction in EFL classrooms. Argues some of Ellis' assumptions about current classroom practices are inaccurate and a number of his "alternative" approaches to teaching grammar, such as…

  13. 32 CFR 989.21 - Record of decision (ROD).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.21 Record of decision (ROD). (a) The proponent and the EPF... all the major factors the agency weighed in making its decision, including essential considerations of... avoid, minimize, or mitigate environmental impacts and, if not, explain why not....

  14. The Construct Validity of the Rod and Frame Test.

    ERIC Educational Resources Information Center

    Schroeder, David H.

    This study examined the construct validity of the Rod and Frame Test (RFT). Subjects were 554 clients (269 males and 285 females) (aged 14 to 65 years) of the Johnson O'Connor Research Foundation (JOCRF), a vocational guidance service. In a battery of diverse ability and style tests (19 tests of the JOCRF battery and 4 tests of cognitive style),…

  15. Efficient wide-aperture neodymium glass rod amplifiers

    SciTech Connect

    Potemkin, A K; Zhurin, K A; Kirsanov, A V; Kopelovich, E A; Kuznetsov, M V; Kuz'min, A A; Flat, F A; Khazanov, Efim A; Shaikin, A A

    2011-06-30

    Amplifiers based on neodymium phosphate glass rods 60 - 100 mm in diameter are experimentally studied. The amplifiers are pumped by INP-16/250 tubular flash lamps placed in a universal pump cavity with a two-section mirror reflector. A compact high-voltage capacitive energy storage with a preionisation circuit was developed to supply the lamps. (lasers)

  16. The Use of Coloured Rods in Teaching Primary Numberwork.

    ERIC Educational Resources Information Center

    Vancouver Public Schools, WA.

    A review of research literature revealed that some researchers felt that the use of colored rods, such as the Cuisenaire materials, in teaching number work gave perceptual support to many relationships. Experiments conducted over 3 years attempted to test some of these relationships. During each year, experimental classes in grade one were…

  17. Flexible Stabilisation of the Degenerative Lumbar Spine Using PEEK Rods.

    PubMed

    Benezech, Jacques; Garlenq, Bruno; Larroque, Gilles

    2016-01-01

    Posterior lumbar interbody fusion using cages, titanium rods, and pedicle screws is considered today as the gold standard of surgical treatment of lumbar degenerative disease and has produced satisfying long-term fusion rates. However this rigid material could change the physiological distribution of load at the instrumental and adjacent segments, a main cause of implant failure and adjacent segment disease, responsible for a high rate of further surgery in the following years. More recently, semirigid instrumentation systems using rods made of polyetheretherketone (PEEK) have been introduced. This clinical study of 21 patients focuses on the clinical and radiological outcomes of patients with lumbar degenerative disease treated with Initial VEOS PEEK(®)-Optima system (Innov'Spine, France) composed of rods made from PEEK-OPTIMA(®) polymer (Invibio Biomaterial Solutions, UK) without arthrodesis. With an average follow-up of 2 years and half, the chances of reoperation were significantly reduced (4.8%), quality of life was improved (ODI = 16%), and the adjacent disc was preserved in more than 70% of cases. Based on these results, combined with the biomechanical and clinical data already published, PEEK rods systems can be considered as a safe and effective alternative solution to rigid ones.

  18. Prosthetic Hand For Holding Rods, Tools, And Handles

    NASA Technical Reports Server (NTRS)

    Belcher, Jewell G., Jr.; Vest, Thomas W.

    1995-01-01

    Prosthetic hand with quick-grip/quick-release lever broadens range of specialized functions available to lower-arm amputee by providing improved capabilities for gripping rods, tools, handles, and like. Includes two stationary lower fingers opposed by one pivoting upper finger. Lever operates in conjunction with attached bracket.

  19. Random Breakage of a Rod into Unit Lengths

    ERIC Educational Resources Information Center

    Gani, Joe; Swift, Randall

    2011-01-01

    In this article we consider the random breakage of a rod into "L" unit elements and present a Markov chain based method that tracks intermediate breakage configurations. The probability of the time to final breakage for L = 3, 4, 5 is obtained and the method is shown to extend in principle, beyond L = 5.

  20. 34. INTERIOR VIEW, SAME AS ABOVE WITH THE FEEDER ROD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. INTERIOR VIEW, SAME AS ABOVE WITH THE FEEDER ROD BEING OFFERED INTO THE MACHINE; UNLIKE THE OTHER NAIL CUTTING MACHINES, THE NAIL PLATE MUST BE HAND FLIPPED AND HAND FED WITH THIS MACHINE - LaBelle Iron Works, Thirtieth & Wood Streets, Wheeling, Ohio County, WV

  1. Safety rod/thimble melt failure characterization experiments

    SciTech Connect

    Stoots, C.M.; Hawkes, G.L.

    1992-05-01

    The Department of Energy (DOE) requested that he INEL perform experiments to study the thermal failure characteristics of a simulated Savannah River Site nuclear reactor safety rod and its surrounding thimble assembly. An electrically heated stainless steel rod simulated a reactor safety rod located eccentrically or concentrically within a perforated aluminum guide tube or thimble. A total of 37 experiments were conducted for a range of power levels and safety rod/thimble relative orientations. Video tapes were made of the four failure tests that were conducted to the melting point of the thimble. Although the primary emphasis of the experiments were to characterize the melting of the thimble qualitatively, experimental transient measurements included heater voltage and current, heater surface temperatures, aluminum thimble temperatures, and ambient temperature. Numerical studies were also performed in support of the experiments and data interpretation. Two finite element models were created to model the heat conduction-radiation between the stainless steel heater and thimble. The predicted temperatures were in good agreement with the experimental results.

  2. Unilateral retinitis pigmentosa and cone-rod dystrophy

    PubMed Central

    Farrell, Donald F

    2009-01-01

    Purpose: The purpose of this paper is to report 14 new cases of unilateral retinitis pigmentosa and three new cases of cone-rod dystrophy and to compare the similarities and dissimilarities to those found in the bilateral forms of these disorders. Methods: A total of 272 cases of retinitis pigmentosa and 167 cases of cone-rod dystrophy were studied by corneal full field electroretinograms and electrooculograms. The student t-test was used to compare categories. Results: The percentage of familial and nonfamilial cases was the same for the bilateral and unilateral forms of the disease. In our series, unilateral retinitis pigmentosa makes up approximately 5% of the total population of retinitis pigmentosa, while unilateral cone-rod dystrophy makes up only about 2% of the total. In the familial forms of unilateral retinitis pigmentosa the most common inheritance pattern was autosomal dominant and all affected relatives had bilateral disease. Conclusion: Unilateral retinitis pigmentosa and cone-rod dystrophy appear to be directly related to the more common bilateral forms of these disorders. The genetic mechanisms which account for asymmetric disorders are not currently understood. It may be a different unidentified mutation at a single loci or it is possible that nonlinked mutations in multiple loci account for this unusual disorder. PMID:19668577

  3. 49 CFR 230.93 - Pistons and piston rods.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Pistons and piston rods. 230.93 Section 230.93 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives...

  4. The Rod and Bottle System: A Problem in Statics

    NASA Astrophysics Data System (ADS)

    MacInnes, Iain

    2005-11-01

    The rod and bottle system (sometimes called the "wine butler"), shown in Fig. 1, is a common statics demonstration in the introductory level physics course. One is immediately attracted to it by the craftsmanship in wood. Thomas Carlyle wrote, "Two men I honour, and no third. The scholar and the craftsman."2 This paper presents an analytic treatment of the system.

  5. Coexistence of central nucleus, cores, and rods: Diagnostic relevance

    PubMed Central

    Dhinakaran, Sathiyabama; Kumar, Rashmi Santhosh; Thakkar, Ravindra; Narayanappa, Gayathri

    2016-01-01

    Background: Congenital myopathies (CMs) though considered distinct disorders, simultaneous occurrence of central nucleus, nemaline rods, and cores in the same biopsy are scarcely reported. Objective: A retrospective reassessment of cases diagnosed as CMs to look for multiple pathologies missed, if any, during the initial diagnosis. Materials and Methods: Enzyme histochemical, and immunohistochemical-stained slides from 125 cases diagnosed as congenital myopathy were reassessed. Results: The study revealed 15 cases (12%) of congenital myopathy with more than one morphological feature. Central nucleus with cores (n = 11), central nucleus, nemaline rods and cores (n = 3), and nemaline rods with cores (n = 1). 4/11 cases were diagnosed as centronuclear myopathy (CNM) in the first instance; in addition, cores were revealed on reassessment. Discussion: The prevalence of CMs of all neuromuscular disorders is approximately 6 in 100,000 live births, with regional variations. Three main defined CMs include centro nuclear myopathy (CNM), nemaline rod myopathy (NRM), and central core disease (CCD). However, they are more diverse with overlapping clinical and histopathological features, thus broadening the spectra within each category of congenital myopathy. Conclusion: Identification of cases with overlap of pathological features has diagnostic relevance. PMID:27293330

  6. Glutamine deprivation initiates reversible assembly of mammalian rods and rings.

    PubMed

    Calise, S John; Carcamo, Wendy C; Krueger, Claire; Yin, Joyce D; Purich, Daniel L; Chan, Edward K L

    2014-08-01

    Rods and rings (RR) are protein assemblies composed of cytidine triphosphate synthetase type 1 (CTPS1) and inosine monophosphate dehydrogenase type 2 (IMPDH2), key enzymes in CTP and GTP biosynthesis. Small-molecule inhibitors of CTPS1 or IMPDH2 induce RR assembly in various cancer cell lines within 15 min to hours. Since glutamine is an essential amide nitrogen donor in these nucleotide biosynthetic pathways, glutamine deprivation was examined to determine whether it leads to RR formation. HeLa cells cultured in normal conditions did not show RR, but after culturing in media lacking glutamine, short rods (<2 μm) assembled after 24 h, and longer rods (>5 μm) formed after 48 h. Upon supplementation with glutamine or guanosine, these RR underwent almost complete disassembly within 15 min. Inhibition of glutamine synthetase with methionine sulfoximine also increased RR assembly in cells deprived of glutamine. Taken together, our data support the hypothesis that CTP/GTP biosynthetic enzymes polymerize to form RR in response to a decreased intracellular level of glutamine. We speculate that rod and ring formation is an adaptive metabolic response linked to disruption of glutamine homeostasis.

  7. Ultrasonic monitoring of material processing using clad buffer rod sensors

    NASA Astrophysics Data System (ADS)

    Ramos Franca, Demartonne

    Ultrasonic sensors and techniques are developed for in-line monitoring of polymer extrusion, cleanliness of molten metals and liquid flow speed at elevated temperature. Pulse-echo mode is used for the first two processes, while the through-transmission mode is applied in the third one. The ultrasonic probe consists of high performance clad buffer rods with different dimensions to thermally isolate the commercial ultrasonic transducer from materials at high temperature. The clad buffer rods are made of steel, polymer and ceramic. Steel clad buffer rods are introduced for in-line monitoring of polymer extrusion processes. Owing to its superior performance in pulse-echo mode, for the first time such a probe is installed and performs ultrasonic monitoring in the die of a co-extrusion machine and in the barrel section of a twin-screw extruder. It can reveal a variety of information relevant to process parameters, such as polymer layer thickness, interface location and adhesion quality, stability, or polymer composition change. For the ultrasonic monitoring of polymer processes, probes with acoustic impedance that matches that of the processed polymer may offer certain advantages such as quantitative viscoelastic evaluation; thus high temperature polymer clad buffer rods, in particular PEEK, are developed. It is demonstrated that this new probe exhibits unique advantages for in-line monitoring of the cure of epoxies and polymer extrusion process. Long steel clad buffer rods with a spherical focus lens machined at the probing end are proposed for cleanliness evaluation of molten metals. The potential of this focusing probe is demonstrated by means of high-resolution imaging and particles detection in molten zinc at temperatures higher than 600°C, using a single probe operated at pulse-echo mode. A contrapropagating ultrasonic flowmeter employing steel clad buffer rods is devised to operate at high temperature. It is demonstrated that these rods guide ultrasonic signals

  8. Microgravity Flammability of PMMA Rods in Concurrent Flow

    NASA Technical Reports Server (NTRS)

    Olson, Sandra L.; Ferkul, Paul V.

    2015-01-01

    Microgravity experiments burning cast PMMA cylindrical rods in axial flow have been conducted aboard the International Space Station in the Microgravity Science Glovebox (MSG) facility using the Burning and Suppression of Solids (BASS) flow duct, as part of the BASS-II experiment. Twenty-four concurrent-flow tests were performed, focusing on finding flammability limits as a function of oxygen and flow speed. The oxygen was varied by using gaseous nitrogen to vitiate the working volume of the MSG. The speed of the flow parallel to the rod was varied using a fan at the entrance to the duct. Both blowoff and quenching limits were obtained at several oxygen concentrations. Each experiment ignited the rod at the initially hemispherical stagnation tip of the rod, and allowed the flame to develop and heat the rod at a sufficient flow to sustain burning. For blowoff limit tests, the astronaut quickly turned up the flow to obtain extinction. Complementary 5.18-second Zero Gravity Facility drop tests were conducted to compare blowoff limits in short and long duration microgravity. For quenching tests, the flow was incrementally turned down and the flame allowed to stabilize at the new flow condition for at least the solid-phase response time before changing it again. Quenching was observed when the flow became sufficiently weak that the flame could no longer provide adequate heat flux to compensate for the heat losses (conduction into the rod and radiation). A surface energy balance is presented that shows the surface radiative loss exceeds the conductive loss into the rod near the limit. The flammability boundary is shown to represent a critical Damkohler number, expressed in terms of the reaction rate divided by the stretch rate. For the blowoff branch, the boundary exhibits a linear dependence on oxygen concentration and stretch rate, indicating that the temperature at blowoff must be fairly constant. For the quenching branch, the dominance of the exponential nature of

  9. Ultra-high strength, self-reinforced absorbable polymeric composites for applications in different disciplines of surgery.

    PubMed

    Törmälä, P

    1993-01-01

    Biodegradable (or absorbable), self-reinforced polymeric composites have potential applications as temporary fixation materials in the treatment of damaged or operated tissues. These materials have high strength and appropriate stiffness and strength retention which can be tailored according to the healing rate of recovering tissues. Macroscopical, absorbable, ultra-high strength, self-reinforced, polymeric composites can be manufactured by creating the polymeric microstructure, where oriented reinforcing elements and matrix material, which have the same chemical element composition, are combined with each other. Self-reinforced materials can be processed into the form of rods, screws, tacks, cerclages, clamps, plates, spirals, etc. Such implants have attractive application possibilities in different disciplines of surgery, such as orthopaedics and traumatology, in maxillofacial, oral and dental surgery and in internal organ surgery.

  10. Reversible Bending Fatigue Testing on Zry-4 Surrogate Rods

    SciTech Connect

    Wang, Jy-An John; Wang, Hong; Bevard, Bruce Balkcom; Howard, Rob L

    2014-01-01

    Testing high-burnup spent nuclear fuel (SNF) presents many challenges in areas such as specimen preparation, specimen installation, mechanical loading, load control, measurements, data acquisition, and specimen disposal because these tasks are complicated by the radioactivity of the test specimens. Research and comparison studies conducted at Oak Ridge National Laboratory (ORNL) resulted in a new concept in 2010 for a U-frame testing setup on which to perform hot-cell reversible bending fatigue testing. Subsequently, the three-dimensional finite element analysis and the engineering design of components were completed. In 2013 the ORNL team finalized the upgrade of the U-frame testing setup and the integration of the U-frame setup into a Bose dual linear motor test bench to develop a cyclic integrated reversible-bending fatigue tester (CIRFT). A final check was conducted on the CIRFT test system in August 2013, and the CIRFT was installed in the hot cell in September 2013 to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The fatigue responses of Zircaloy-4 (Zry-4) cladding and the role of pellet pellet and pellet clad interactions are critical to SNF vibration integrity, but such data are not available due to the unavailability of an effective testing system. While the deployment of the developed CIRFT test system in a hot cell will provide the opportunity to generate the data, the use of a surrogate rod has proven quite effective in identifying the underlying deformation mechanism of an SNF composite rod under an equivalent loading condition. This paper presents the experimental results of using surrogate rods under CIRFT reversible cyclic loading. Specifically, monotonic and cyclic bending tests were conducted on surrogate rods made of a Zry-4 tube and alumina pellet inserts, both with and without an epoxy bond.

  11. Non-Absorbable Gas Behavior in the Absorber/Evaporator of a Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiroshi; Nagamoto, Wataru; Sugiyama, Takahide

    A two-dimensional numerical study on non-absorbable gas behavior in the absorber/evaporator of an absorption chiller has been performed. In the present study, the effect of the pitch-to-diameter ratio of a cylinder bundle in the absorber was highlighted. From the results, a sudden decrease of the overall heat transfer coefficient of the absorber was observed at a certain mean concentration of non-absorbable gas for each pitch-to-diameter ratio. Such a critical concentration was also found to decrease as the pitch-to- diameter ratio increased. The sudden decrease occurs due to the sudden disappearance of recirculating region, which is formed between the absorber and the evaporator, and where most of non-absorbable gas stays when it exists. As the pitch-to-diameter ratio increases, the recirculating region becomes weak because the velocity of the high velocity region supporting the recirculating flow decreases. Then, the critical mean concentration of non-absorbable gas is found to decrease as pitch-to-ratio increases.

  12. Optical analysis of solar energy tubular absorbers.

    PubMed

    Saltiel, C; Sokolov, M

    1982-11-15

    The energy absorbed by a solar energy tubular receiver element for a single incident ray is derived. Two types of receiver elements were analyzed: (1) an inner tube with an absorbing coating surrounded by a semitransparent cover tube, and (2) a semitransparent inner tube filled with an absorbing fluid surrounded by a semitransparent cover tube. The formation of ray cascades in the semitransparent tubes is considered. A numerical simulation to investigate the influence of the angle of incidence, sizing, thickness, and coefficient of extinction of the tubes was performed. A comparison was made between receiver elements with and without cover tubes. Ray tracing analyses in which rays were followed within the tubular receiver element as well as throughout the rest of the collector were performed for parabolic and circular trough concentrating collectors.

  13. Interference theory of metamaterial perfect absorbers.

    PubMed

    Chen, Hou-Tong

    2012-03-26

    The impedance matching to free space in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with direct evidence provided by the anti-parallel surface currents in the metal structures. Here I present a different theoretical interpretation based on interference, which shows that the two layers of metal structures in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

  14. Translatory shock absorber for attitude sensors

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.; Morgan, I. T., Jr.; Kirby, C. A. (Inventor)

    1976-01-01

    A translatory shock absorber is provided for mounting an attitude sensor thereon for isolating a sensor from translatory vibrations. The translatory shock absorber includes a hollow block structure formed as one piece to form a parallelogram. The absorber block structure includes a movable top plate for supporting the attitude sensor and a fixed base plate with opposed side plates interposed between. At the junctions of the side plates, and the base and top plates, there are provided grooves which act as flexible hinges for attenuating translatory vibrations. A damping material is supported on a pedestal which is carried on the base plate between the side plates thereof. The top of the damping material rests against the bottom surface of the top plate for eliminating the resonant peaks of vibration.

  15. Absorber Materials at Room and Cryogenic Temperatures

    SciTech Connect

    F. Marhauser, T.S. Elliott, A.T. Wu, E.P. Chojnacki, E. Savrun

    2011-09-01

    We recently reported on investigations of RF absorber materials at cryogenic temperatures conducted at Jefferson Laboratory (JLab). The work was initiated to find a replacement material for the 2 Kelvin low power waveguide Higher Order Mode (HOM) absorbers employed within the original cavity cryomodules of the Continuous Electron Beam Accelerator Facility (CEBAF). This effort eventually led to suitable candidates as reported in this paper. Furthermore, though constrained by small funds for labor and resources, we have analyzed a variety of lossy ceramic materials, several of which could be usable as HOM absorbers for both normal conducting and superconducting RF structures, e.g. as loads in cavity waveguides and beam tubes either at room or cryogenic temperatures and, depending on cooling measures, low to high operational power levels.

  16. Ferrite HOM Absorber for the RHIC ERL

    SciTech Connect

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  17. Coolant mixing in LMFBR rod bundles and outlet plenum mixing transients. Progress report, March 1, 1980-May 31, 1980

    SciTech Connect

    Todreas, N.E.; Golay, M.W.; Wolf, L.

    1980-01-01

    Experimental and theoretical work is reported on four tasks: bundle geometry (wrapped and bare rods), subchannel geometry (bare rods), LMFBR outlet plenum flow mixing, and theoretical local temperature files in LMFBR fuel rod bundles. (DLC)

  18. Comparison of a center and off-center BWR control rod drop accident

    SciTech Connect

    Cokinos, D.M.; Neogy, P.; Carew, J.F.

    1984-07-01

    A BWR control rod drop accident (RDA) induces a rapid core power transient involving strong neutronic/thermal-hydraulic coupling, which requires a detailed multi-dimensional spatial kinetics analysis. Typical two-dimensional (r,z) RDA calculations require that the dropped rod be a center rod, as a result of geometric limitations, while in three-dimensional (x,y,z) calculations the dropped rod is generally taken to be the center rod in order to allow a quarter-core representation and limit computer running times. However, for typical BWR core loadings, the highest worth rod is not necessarily the center rod and it is not known, a priori, what effect this difference in spatial location has on the RDA dynamics. In order to evaluate the effects of this simplification, three-dimensional RAMONA-3B calculations have been performed for both a center and off-center control rod drop accident.

  19. Correlated and uncorrelated invisible temporal white noise alters mesopic rod signaling.

    PubMed

    Hathibelagal, Amithavikram R; Feigl, Beatrix; Kremers, Jan; Zele, Andrew J

    2016-03-01

    We determined how rod signaling at mesopic light levels is altered by extrinsic temporal white noise that is correlated or uncorrelated with the activity of one (magnocellular, parvocellular, or koniocellular) postreceptoral pathway. Rod and cone photoreceptor excitations were independently controlled using a four-primary photostimulator. Psychometric (Weibull) functions were measured for incremental rod pulses (50 to 250 ms) in the presence (or absence; control) of perceptually invisible subthreshold extrinsic noise. Uncorrelated (rod) noise facilitates rod detection. Correlated postreceptoral pathway noise produces differential changes in rod detection thresholds and decreases the slope of the psychometric functions. We demonstrate that invisible extrinsic noise changes rod-signaling characteristics within the three retinogeniculate pathways at mesopic illumination depending on the temporal profile of the rod stimulus and the extrinsic noise type.

  20. Optimization and engineering of microwave absorbers

    NASA Astrophysics Data System (ADS)

    Chen, Kuo-Liang

    1998-12-01

    In this thesis, a concerted effort has been made to study and evaluate the individual electromagnetic properties of the absorbing components including carbon black, conducting fibers, metal flakes, magnetic materials such as carbonyl iron, ferrite and the chiral type of micro- carbon coil. The study of the electromagnetic properties covers functions such as dielectric dissipation, random scattering effect at low and high frequencies, magnetic dissipation at high frequencies and also the effect of chirality for different angles of incidence. The results of these studies have been used in the design, engineering and optimization of the microwave absorbers. The objective of this thesis is to identify the absorption mechanism of each of various type of fillers and to study the synergic effect arising from a combination of these in a non-metallic host medium. This will help us in producing microwave absorbers suitable for broad band application with the advantages of light weight, having high strength and possessing good chemical resistance. The results from experimental measurements of various material combinations have been greatly influenced by the theoretical understanding of the absorption mechanism. Design of microwave absorbers is governed by the requirement of the users as well as the characteristics of the objects (targets) inferred by theoretical understanding and experimental data to arrive at the right formula. Finally a detailed quality control program has to be charted out reflecting both the electromagnetic as well as mechanical properties. This is done by carrying out the tests systematically on small samples and then proceeding to practical absorbers making use of the data compiled earlier on smaller samples. In this thesis, to modify all dielectric absorbing components including micro-carbon chirals to reduce the sensitivity of absorption for different incident angles is unprecedented topic.