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Sample records for control rod trip

  1. 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)

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. 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.

  7. 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.

  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. 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)

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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)

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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%.

  2. 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).

  3. 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.

  4. 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)

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. VIEW OF CABLES AND TAPES ASSOCIATED WITH ADRIVE CONTROL ROD ...

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

    VIEW OF CABLES AND TAPES ASSOCIATED WITH A-DRIVE CONTROL ROD SYSTEM, AT LEVEL +15’, DIRECTLY ABOVE PDP CONTROL ROOM, LOOKING NORTHWEST. THE CABLES FROM THE PDP ROOM GO THROUGH THE CONCRETE WALL, MAKE A RIGHT ANGLE TURN DOWNWARD, AND DESCEND INTO THE PDP CONTROL ROOM AS VERTICAL TAPES - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

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

    DOEpatents

    Smith, J.E.

    Disclosed is a linear motion device and more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core. The CRDM and method disclosed 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.

  11. Implementation of CTRLPOS, a VENTURE module for control rod position criticality searches, control rod worth curve calculations, and general criticality searches

    SciTech Connect

    Smith, L.A.; Renier, J.P.

    1994-06-01

    A module in the VENTURE reactor analysis code system, CTRLPOS, is developed to position control rods and perform control rod position criticality searches. The module is variably dimensioned so that calculations can be performed with any number of control rod banks each having any number of control rods. CTRLPOS can also calculate control rod worth curves for a single control rod or a bank of control rods. Control rod depletion can be calculated to provide radiation source terms. These radiation source terms can be used to predict radiation doses to personnel and estimate the shielding and long-term storage requirements for spent control rods. All of these operations are completely automated. The numerous features of the module are discussed in detail. The necessary input data for the CTRLPOS module is explained. Several sample problems are presented to show the flexibility of the module. The results presented with the sample problems show that the CTRLPOS module is a powerful tool which allows a wide variety of calculations to be easily performed.

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

    SciTech Connect

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

    1989-12-19

    This patent describes, in a reconstitutable control assembly for use with a nuclear fuel assembly, the control assembly including a spider structure and at least one control rod, an attachment joint for detachable fastening the control rod to the spider structure. The attachment joint comprising: a hollow connecting finger on the spider structure; and an elongated detachable split upper end plug on the control rod having a pair of separate upper and lower plug portions, the upper plug portion having integrally-connected tandemly- arranged upper, middle and lower sections. The lower plug portion having integrally-connected tandemly-arranged upper, middle and lower segments.

  13. A robust and high-performance queue management controller for large round trip time networks

    NASA Astrophysics Data System (ADS)

    Khoshnevisan, Ladan; Salmasi, Farzad R.

    2016-05-01

    Congestion management for transmission control protocol is of utmost importance to prevent packet loss within a network. This necessitates strategies for active queue management. The most applied active queue management strategies have their inherent disadvantages which lead to suboptimal performance and even instability in the case of large round trip time and/or external disturbance. This paper presents an internal model control robust queue management scheme with two degrees of freedom in order to restrict the undesired effects of large and small round trip time and parameter variations in the queue management. Conventional approaches such as proportional integral and random early detection procedures lead to unstable behaviour due to large delay. Moreover, internal model control-Smith scheme suffers from large oscillations due to the large round trip time. On the other hand, other schemes such as internal model control-proportional integral and derivative show excessive sluggish performance for small round trip time values. To overcome these shortcomings, we introduce a system entailing two individual controllers for queue management and disturbance rejection, simultaneously. Simulation results based on Matlab/Simulink and also Network Simulator 2 (NS2) demonstrate the effectiveness of the procedure and verify the analytical approach.

  14. Internal Control Rod Drive Mechanisms, Design Options for IRIS

    SciTech Connect

    Conway, Lawrence E.; Petrovic, Bojan

    2004-07-01

    IRIS (International Reactor Innovative and Secure) is a medium-power (335 MWe) PWR with an integral, primary circuit configuration, where all the reactor coolant system components are contained within the reactor vessel. This integral configuration is a key reason for the success of IRIS' 'safety-by-design' approach, whereby accident initiators are eliminated or the accident consequences and/or frequency are reduced. The most obvious example of the IRIS safety by design approach is the elimination of large LOCA's, since the integral reactor coolant system has no large loop piping. Another serious accident scenario that is being addressed in IRIS is the postulated ejection of a reactor control cluster assembly (RCCA). This accident initiator can be eliminated by locating the RCCA drive mechanisms (CRDMs) inside the reactor vessel. This eliminates the mechanical drive rod penetration between the RCCA and the external CRDM, eliminating the potential for differential pressure across the pressure boundary, and thus eliminating 'by design' the possibility for rod ejection accident. Moreover, the elimination of the 'large' drive-rod penetrations and the external CRDM pressure housings decreases the likelihood of boric acid leakage and subsequent corrosion of the reactor pressure boundary (like the Davis-Besse incident). This paper will discuss the IRIS top level design requirements and objectives for internal CRDMs, and provide examples candidate designs and their specific performance characteristics. (authors)

  15. Control rod system useable for fuel handling in a gas-cooled nuclear reactor

    DOEpatents

    Spurrier, Francis R.

    1976-11-30

    A control rod and its associated drive are used to elevate a complete stack of fuel blocks to a position above the core of a gas-cooled nuclear reactor. A fuel-handling machine grasps the control rod and the drive is unlatched from the rod. The stack and rod are transferred out of the reactor, or to a new location in the reactor, by the fuel-handling machine.

  16. 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.

  17. Analysis of High Temperature Reactor Control Rod Worth for the Initial and Full Core

    NASA Astrophysics Data System (ADS)

    Oktajianto, Hammam; Setiawati, Evi; Anam, Khoirul; Sugito, Heri

    2017-01-01

    Control rod is one important component in a nuclear reactor. In nuclear reactor operations the control rod functions to shut down the reactor. This research analyses ten control rods worth of HTR (High Temperature Reactor) at initial and full core. The HTR in this research adopts HTR-10 China and HTR- of pebble bed. Core calculations are performed by using MCNPX code after modelling the entire parts of core in condition of ten control rods fully withdrawn, all control rods in with 20 cm ranges of depth and the use of one control rod. Pebble bed and moderator balls are distributed in the core zone using a Body Centred Cubic (BCC) lattice by ratio of 57:43. The research results are obtained that the use of one control rod will decrease the reactor criticality of 2.04±0.12 %Δk/k at initial core and 1.57±0.10 %Δk/k at full core. The deeper control rods are in, the lesser criticality of reactor is with reactivity of ten control rods of 16.41±0.11 %Δk/k at initial core and 15.43±0.11 %Δk/k at full core. The results show that the use of ten control rods at full core will keep achieving subcritical condition even though the reactivity is smaller than reactivity at initial core.

  18. Underwater characterization of control rods for waste disposal using SMOPY

    SciTech Connect

    Gallozzi-Ulmann, A.; Couturier, P.; Amgarou, K.; Rothan, D.; Menaa, N.; Chard, P.

    2015-07-01

    Storage of spent fuel assemblies in cooling ponds requires careful control of the geometry and proximity of adjacent assemblies. Measurement of the fuel burnup makes it possible to optimise the storage arrangement of assemblies taking into account the effect of the burnup on the criticality safety margins ('burnup credit'). Canberra has developed a measurement system for underwater measurement of spent fuel assemblies. This system, known as 'SMOPY', performs burnup measurements based on gamma spectroscopy (collimated CZT detector) and neutron counting (fission chamber). The SMOPY system offers a robust and waterproof detection system as well as the needed capability of performing radiometric measurements in the harsh high dose - rate environments of the cooling ponds. The gamma spectroscopy functionality allows powerful characterization measurements to be performed, in addition to burnup measurement. Canberra has recently performed waste characterisation measurements at a Nuclear Power Plant. Waste activity assessment is important to control costs and risks of shipment and storage, to ensure that the activity level remains in the range allowed by the facility, and to declare activity data to authorities. This paper describes the methodology used for the SMOPY measurements and some preliminary results of a radiological characterisation of AIC control rods. After describing the features and normal operation of the SMOPY system, we describe the approach used for establishing an optimum control rod geometric scanning approach (optimum count time and speed) and the method of the gamma spectrometry measurements as well as neutron check measurements used to verify the absence of neutron sources in the waste. We discuss the results obtained including {sup 60}Co, {sup 110m}Ag and {sup 108m}Ag activity profiles (along the length of the control rods) and neutron results including Total Measurement Uncertainty evaluations. Full self-consistency checks were performed and these

  19. Final Report: Contractor Readiness Assessment (CRA) for TREAT Fuel Movement and Control Rod Drives Isolation

    SciTech Connect

    Rowsell, David Leon

    2015-06-01

    This report documents the Contractor Readiness Assessment (CRA) for TREAT Fuel Movement and Control Rod Drives Isolation. The review followed the approved Plan of Action (POA) and Implementation Plan (IP) using the identified core requirements. The activity was limited scope focusing on the control rod drives functional isolation and fuel element movement. The purpose of this review is to ensure the facility's readiness to move fuel elements thus supporting inspection and functionally isolate the control rod drives to maintain the required shutdown margin.

  20. 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.

  1. 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.

  2. Optimization of boiling water reactor control rod patterns using linear search

    SciTech Connect

    Kiguchi, T.; Doi, K.; Fikuzaki, T.; Frogner, B.; Lin, C.; Long, A.B.

    1984-10-01

    A computer program for searching the optimal control rod pattern has been developed. The program is able to find a control rod pattern where the resulting power distribution is optimal in the sense that it is the closest to the desired power distribution, and it satisfies all operational constraints. The search procedure consists of iterative uses of two steps: sensitivity analyses of local power and thermal margins using a three-dimensional reactor simulator for a simplified prediction model; linear search for the optimal control rod pattern with the simplified model. The optimal control rod pattern is found along the direction where the performance index gradient is the steepest. This program has been verified to find the optimal control rod pattern through simulations using operational data from the Oyster Creek Reactor.

  3. Independent safety evaluation of the CR562 (CR6) control rod test

    SciTech Connect

    Van Keuren, J.C.

    1988-10-01

    This report documents the Independent Safety Evaluation performed for the CR562 control rod. CR562 is a reference Series II control rod which has been designated as an experiment (CR-6) since post- irradiation examination has been planned as part of the surveillance program for FFTF control rods. Prior analysis as an experiment has not been required since the test operated within the Technical Specification Limits up to this time. The control rod will be operated beyond the Technical Specification fluence limit during the last 30 days of Cycle 10B. A TDD-1A has been written to support this extension, and this ISE documents the independent review. A similar procedure was used for the CR544 control rod. 9 refs.

  4. Stability and optimised H∞ control of tripped and untripped vehicle rollover

    NASA Astrophysics Data System (ADS)

    Jin, Zhilin; Zhang, Lei; Zhang, Jiale; Khajepour, Amir

    2016-10-01

    Vehicle rollover is a serious traffic accident. In order to accurately evaluate the possibility of untripped and some special tripped vehicle rollovers, and to prevent vehicle rollover under unpredictable variations of parameters and harsh driving conditions, a new rollover index and an anti-roll control strategy are proposed in this paper. Taking deflections of steering and suspension induced by the roll at the axles into consideration, a six degrees of freedom dynamic model is established, including lateral, yaw, roll, and vertical motions of sprung and unsprung masses. From the vehicle dynamics theory, a new rollover index is developed to predict vehicle rollover risk under both untripped and special tripped situations. This new rollover index is validated by Carsim simulations. In addition, an H-infinity controller with electro hydraulic brake system is optimised by genetic algorithm to improve the anti-rollover performance of the vehicle. The stability and robustness of the active rollover prevention control system are analysed by some numerical simulations. The results show that the control system can improve the critical speed of vehicle rollover obviously, and has a good robustness for variations in the number of passengers and longitude position of the centre of gravity.

  5. Effect of component aging on PWR control rod drive systems

    SciTech Connect

    Grove, E.; Gunther, W.; Sullivan, K.

    1992-01-01

    An aging assessment of PWR control rod drive (CRD) systems has been completed as part of the US NRC Nuclear Plant Aging Research (NPAR) Program. The design, construction, maintenance, and operation of the Babcock Wilcox (B W), Combustion Engineering (CE), and Westinghouse (W) systems were evaluated to determine the potential for degradation as each system ages. Operating experience data were evaluated to identify the predominant failure modes, causes, and effects. This, coupled with an assessment of the materials of construction and operating environment, demonstrate that each design is subject to degradation, which if left unchecked, could affect its safety function as the plant ages. An industry survey, conducted with the assistance of EPRI and NUMARC, identified current CRD system maintenance and inspection practices. The results of this survey indicate that some plants have performed system modifications, replaced components, or augmented existing preventive maintenance practices in response to system aging. The survey results also supported the operating experience data, which concluded that the timely replacement of degraded components, prior to failure, was not always possible using existing condition monitoring techniques. The recommendations presented in this study also include a discussion of more advanced monitoring techniques, which provide trendable results capable of detecting aging.

  6. Effect of component aging on PWR control rod drive systems

    SciTech Connect

    Grove, E.; Gunther, W.; Sullivan, K.

    1992-06-01

    An aging assessment of PWR control rod drive (CRD) systems has been completed as part of the US NRC Nuclear Plant Aging Research (NPAR) Program. The design, construction, maintenance, and operation of the Babcock & Wilcox (B & W), Combustion Engineering (CE), and Westinghouse (W) systems were evaluated to determine the potential for degradation as each system ages. Operating experience data were evaluated to identify the predominant failure modes, causes, and effects. This, coupled with an assessment of the materials of construction and operating environment, demonstrate that each design is subject to degradation, which if left unchecked, could affect its safety function as the plant ages. An industry survey, conducted with the assistance of EPRI and NUMARC, identified current CRD system maintenance and inspection practices. The results of this survey indicate that some plants have performed system modifications, replaced components, or augmented existing preventive maintenance practices in response to system aging. The survey results also supported the operating experience data, which concluded that the timely replacement of degraded components, prior to failure, was not always possible using existing condition monitoring techniques. The recommendations presented in this study also include a discussion of more advanced monitoring techniques, which provide trendable results capable of detecting aging.

  7. Ultrasound control of magnet growing rod distraction in early onset scoliosis.

    PubMed

    Pérez Cervera, T; Lirola Criado, J F; Farrington Rueda, D M

    2016-01-01

    The growing rod technique is currently one of the most common procedures used in the management of early onset scoliosis. However, in order to preserve spine growth and control the deformity it requires frequent surgeries to distract the rods. Magnetically driven growing rods have recently been introduced with same treatment goal, but without the inconvenience of repeated surgical distractions. One of the limitations of this technical advance is an increase in radiation exposure due to the increase in distraction frequency compared to conventional growing rods. An improvement of the original technique is presented, proposing a solution to the inconvenience of multiple radiation exposure using ultrasound technology to control the distraction process of magnetically driven growing rods.

  8. A survey of control rod measurements in ZPPR and their analysis

    SciTech Connect

    Collins, P.J.

    1988-01-01

    The accurate prediction of control rod worths has been of great concern in the United States. Optimum control configurations need to balance several often conflicting requirements of control through the operating cycle, while maintaining acceptable power shapes, safety considerations of overriding importance, together with seeking economy by minimizing the number of rods, reducing boron enrichment and lengthening replacement intervals. After control and shutdown requirements have been met, the most important safety concern is the transient overpower condition (TOP) which may be initiated by uncontrolled run-out of a primary rod. Stringent criteria for the primary and secondary systems may be that they are independently capable of shutting down the reactor even with one rod stuck. The TOP initiator may be greatly enhanced by control rod interaction effects. Control rod effects may have a strong impact on core design. For example, work on the integral fast reactor with metallic fuel at ANL has studied core designs which minimize the TOP reactivity by maintaining a minimum primary control bank insertion through tailoring the internal breeding gain. The predicted control rod worths are very sensitive to the calculation methods used and to the accuracy of the basic nuclear data files. Required accuracies have been achieved only through the use of critical experiments on the ZPR and ZPPR facilities. Experiments on ZPR-3 and ZPR-9 produced satisfactory control predictions for the SEFOR, EBR-II and FFTF reactors. This document provides a survey of control rod measurements and compares calculated and experimental results. 16 refs., 3 figs., 10 tabs.

  9. Sample Federal Facility Land Use Control ROD Checklist and Suggested Language (LUC Checklist)

    EPA Pesticide Factsheets

    The LUC Checklist provides direction on describing and documenting land use controls (LUCs) in federal facility actrions under CERCLA in Records of Decision (RODs), remedial designs (RDs), and remedial action work plans (RAWPs).

  10. Validation of neutron flux redistribution factors in JSI TRIGA reactor due to control rod movements.

    PubMed

    Kaiba, Tanja; Žerovnik, Gašper; Jazbec, Anže; Štancar, Žiga; Barbot, Loïc; Fourmentel, Damien; Snoj, Luka

    2015-10-01

    For efficient utilization of research reactors, such as TRIGA Mark II reactor in Ljubljana, it is important to know neutron flux distribution in the reactor as accurately as possible. The focus of this study is on the neutron flux redistributions due to control rod movements. For analyzing neutron flux redistributions, Monte Carlo calculations of fission rate distributions with the JSI TRIGA reactor model at different control rod configurations have been performed. Sensitivity of the detector response due to control rod movement have been studied. Optimal radial and axial positions of the detector have been determined. Measurements of the axial neutron flux distribution using the CEA manufactured fission chambers have been performed. The experiments at different control rod positions were conducted and compared with the MCNP calculations for a fixed detector axial position. In the future, simultaneous on-line measurements with multiple fission chambers will be performed inside the reactor core for a more accurate on-line power monitoring system.

  11. Experimental investigations on a tapered ferrite rod antenna with magnetic phase control

    NASA Astrophysics Data System (ADS)

    Petosa, A.; Wight, J. S.; Ittipiboon, A.

    1994-08-01

    Experimental investigations were performed on a tapered ferrite rod antenna at 20 GHz. By inserting a section of the rod into a solenoid, phase control was achieved by varying the applied DC solenoid current. Phase shifts of greater than 100 deg/lambda(0) were attained. The gain and radiation patterns did not change significantly with the applied bias. The return loss was somewhat more sensitive, but a better than 10dB return loss was obtained over the complete bias range.

  12. Estimation of the activity generated by neutron activation in control rods of a BWR.

    PubMed

    Ródenas, José; Gallardo, Sergio; Abarca, Agustín; Juan, Violeta

    2010-01-01

    Control rods are activated by neutron reactions into the reactor. The activation is produced mainly in stainless steel and its impurities. The dose produced by this activity is not important inside the reactor, but it has to be taken into account when the rod is withdrawn from the reactor. Activation reactions produced have been modelled by the MCNP5 code based on the Monte Carlo method. The code gives the number of reactions that can be converted into activity.

  13. 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).

  14. Rod electrical coupling is controlled by a circadian clock and dopamine in mouse retina

    PubMed Central

    Jin, Nan Ge; Chuang, Alice Z; Masson, Philippe J; Ribelayga, Christophe P

    2015-01-01

    Key points Rod photoreceptors play a key role in vision in dim light; in the mammalian retina, although rods are anatomically connected or coupled by gap junctions, a type of electrical synapse, the functional importance and regulation of rod coupling has remained elusive. We have developed a new technique in the mouse: perforated patch-clamp recording of rod inner segments in isolated intact retinae maintained by superfusion. We find that rod electrical coupling is controlled by a circadian clock and dopamine, and is weak during the day and stronger at night. The results also indicate that the signal-to-noise ratio for a dim light response is increased at night because of coupling. Our observations will provide a framework for understanding the daily variations in human vision as well as the basis of specific retinal malfunctions. Abstract Rod single-photon responses are critical for vision in dim light. Electrical coupling via gap junction channels shapes the light response properties of vertebrate photoreceptors, but the regulation of rod coupling and its impact on the single-photon response have remained unclear. To directly address these questions, we developed a perforated patch-clamp recording technique and recorded from single rod inner segments in isolated intact neural mouse retinae, maintained by superfusion. Experiments were conducted at different times of the day or under constant environmental conditions, at different times across the circadian cycle. We show that rod electrical coupling is regulated by a circadian clock and dopamine, so that coupling is weak during the day and strong at night. Altogether, patch-clamp recordings of single-photon responses in mouse rods, tracer coupling, receptive field measurements and pharmacological manipulations of gap junction and dopamine receptor activity provide compelling evidence that rod coupling is modulated in a circadian manner. These data are consistent with computer modelling. At night, single

  15. 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.

  16. TRIPPING CIRCUIT

    DOEpatents

    Lees, G.W.; McCormick, E.D.

    1962-05-22

    A tripping circuit employing a magnetic amplifier for tripping a reactor in response to power level, period, or instrument failure is described. A reference winding and signal winding are wound in opposite directions on the core. Current from an ion chamber passes through both windings. If the current increases at too fast a rate, a shunt circuit bypasses one or the windings and the amplifier output reverses polarity. (AEC)

  17. Experience with incomplete control rod insertion in fuel with burnup exceeding approximately 40 GWD/MTU

    SciTech Connect

    Kee, E.

    1997-01-01

    Analysis and measurement experience with fuel assemblies having incomplete control rod insertion at burnups of approximately 40 GWD/MTU is presented. Control rod motion dynamics and simplified structural analyses are presented and compared to measurement data. Fuel assembly growth measurements taken with the plant Refueling Machine Z-Tape are described and presented. Bow measurements (including plug gauging) are described and potential improvements are suggested. The measurements described and analysis performed show that sufficient guide tube bow (either from creep or yield buckling) is present in some high burnup assemblies to stop the control rods before they reach their full limit of travel. Recommendations are made that, if implemented, could improve cost performance related to testing and analysis activities.

  18. 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.

  19. Degradation in steam of 60 cm-long B4C control rods

    NASA Astrophysics Data System (ADS)

    Dominguez, C.; Drouan, D.

    2014-08-01

    In the framework of nuclear reactor core meltdown accident studies, the degradation of boron carbide control rod segments exposed to argon/steam atmospheres was investigated up to about 2000 °C in IRSN laboratories. The sequence of the phenomena involved in the degradation has been found to take place as expected. Nevertheless, the ZrO2 oxide layer formed on the outer surface of the guide tube was very protective, significantly delaying and limiting the guide tube failure and therefore the boron carbide pellet oxidation. Contrary to what was expected, the presence of the control rod decreases the hydrogen release instead of increasing it by additional oxidation of boron compounds. Boron contents up to 20 wt.% were measured in metallic mixtures formed during degradation. It was observed that these metallic melts are able to attack the surrounding fuel rods, which could have consequences on fuel degradation and fission product release kinetics during severe accidents.

  20. Subplane-based Control Rod Decusping Techniques for the 2D/1D Method in MPACT

    SciTech Connect

    Graham, Aaron M; Collins, Benjamin S; Downar, Thomas

    2017-01-01

    The MPACT transport code is being jointly developed by Oak Ridge National Laboratory and the University of Michigan to serve as the primary neutron transport code for the Virtual Environment for Reactor Applications Core Simulator. MPACT uses the 2D/1D method to solve the transport equation by decomposing the reactor model into a stack of 2D planes. A fine mesh flux distribution is calculated in each 2D plane using the Method of Characteristics (MOC), then the planes are coupled axially through a 1D NEM-P$_3$ calculation. This iterative calculation is then accelerated using the Coarse Mesh Finite Difference method. One problem that arises frequently when using the 2D/1D method is that of control rod cusping. This occurs when the tip of a control rod falls between the boundaries of an MOC plane, requiring that the rodded and unrodded regions be axially homogenized for the 2D MOC calculations. Performing a volume homogenization does not properly preserve the reaction rates, causing an error known as cusping. The most straightforward way of resolving this problem is by refining the axial mesh, but this can significantly increase the computational expense of the calculation. The other way of resolving the partially inserted rod is through the use of a decusping method. This paper presents new decusping methods implemented in MPACT that can dynamically correct the rod cusping behavior for a variety of problems.

  1. Analysis of dose rates received around the storage pool for irradiated control rods in a BWR nuclear power plant.

    PubMed

    Ródenas, J; Abarca, A; Gallardo, S

    2011-08-01

    BWR control rods are activated by neutron reactions in the reactor. The dose produced by this activity can affect workers in the area surrounding the storage pool, where activated rods are stored. Monte Carlo (MC) models for neutron activation and dose assessment around the storage pool have been developed and validated. In this work, the MC models are applied to verify the expected reduction of dose when the irradiated control rod is hanged in an inverted position into the pool.

  2. Special article: Update on the magnetically controlled growing rod: tips and pitfalls.

    PubMed

    Cheung, Jason Pui Yin; Cahill, Patrick; Yaszay, Burt; Akbarnia, Behrooz A; Cheung, Kenneth M C

    2015-12-01

    Magnetically controlled growing rods (MCGR) have become an important treatment option in young patients with spinal deformities. This device allows for gradual lengthening on an outpatient setting with continuous neurological monitoring in an awake patient. With its growing popularity and interest, this study reports the tips, pitfalls, and complications of the MCGR for management of scoliosis. On 3 June 2015 at the University of Hong Kong, 32 participants from 16 regions shared their experience with MCGR. Current indications for surgery include early-onset scoliosis patients. Adolescent idiopathic scoliosis and congenital scoliosis patients have less favourable outcomes. The number of instrumented levels should be minimised, as all instrumented levels must be included in the definitive fusion surgery. Rod contouring is important and owing to the straight portion of the rod housing the magnet, there is limited proximal rod portion for proper contouring, which may predispose to proximal junctional kyphosis. There is currently no consensus on the rod configuration, timing, frequency, technique, and amount of distraction. Risk factors for distraction failure include larger patients, internal magnets too close to each other, and magnets too close to the apex of the major curve. Future studies should resolve the issues regarding the technique of distraction, optimal frequency and amount of distraction per session. More comprehensive cost analyses should be performed.

  3. Prediction of the lifetime of the elements of the safety and control rods of nuclear reactors

    SciTech Connect

    Voskoboinikov, V.V.; Emel'yanov, I. Ya.; Lineva, A.F.; Pushkin, S.N.; Semchenko, E.L.; Usov, P.P.

    1987-07-01

    The authors construct a mathematical model based on the analytical solution to such parameters as magnetic flux, alignment, sliding friction, erosion, abrasion, corrosion, and irradiation for the purpose of predicting the service life of electromagnetically driven control rods and their drives. The analytical solution was verified experimentally on a bench simulation where it was found that incorrect assembly and alignment not only serve as the largest contributors to shortened service life of the rods and drives but also render the calculations of the model invalid.

  4. Quantitative uncertainty and sensitivity analysis of a PWR control rod ejection accident

    SciTech Connect

    Pasichnyk, I.; Perin, Y.; Velkov, K.

    2013-07-01

    The paper describes the results of the quantitative Uncertainty and Sensitivity (U/S) Analysis of a Rod Ejection Accident (REA) which is simulated by the coupled system code ATHLET-QUABOX/CUBBOX applying the GRS tool for U/S analysis SUSA/XSUSA. For the present study, a UOX/MOX mixed core loading based on a generic PWR is modeled. A control rod ejection is calculated for two reactor states: Hot Zero Power (HZP) and 30% of nominal power. The worst cases for the rod ejection are determined by steady-state neutronic simulations taking into account the maximum reactivity insertion in the system and the power peaking factor. For the U/S analysis 378 uncertain parameters are identified and quantified (thermal-hydraulic initial and boundary conditions, input parameters and variations of the two-group cross sections). Results for uncertainty and sensitivity analysis are presented for safety important global and local parameters. (authors)

  5. Parallel Magnetic Flow Electromagnet for Movable Coil Control-rod Driving Mechanism

    SciTech Connect

    Jige, Zhang

    2006-07-01

    The parallel magnetic flow electromagnet can effectively relax the saturation, which easily takes place in the single magnetic flow electromagnet, and accordingly can improve the drive capacity of the movable coil electromagnet drive mechanism for a mobile reactor control rod. (authors)

  6. Towards ultra-high ductility TRIP-assisted multiphase steels controlled by strain gradient plasticity effects

    NASA Astrophysics Data System (ADS)

    Hatami, M. K.; Pardoen, T.; Lacroix, G.; Berke, P.; Jacques, P. J.; Massart, T. J.

    2017-01-01

    TRansformation Induced Plasticity (TRIP) is a very effective mechanism to increase the strain hardening capacity of multiphase steels containing a fraction of metastable austenite, leading to both high strength and large uniform elongation. Excellent performances have been reached in the past 20 years, with recent renewed interest through the development of the 3rd generation of high strength steels often involving a TRIP effect. The microstructure and composition optimization is complex due to the interplay of coupled effects on the transformation kinetics and work hardening such as phase stability, size of retained austenite grains, temperature and loading path. In particular, recent studies have shown that the TRIP effect can only be quantitatively captured for realistic microstructures if strain gradient plasticity effects are taken into account, although direct experimental validation of this claim is missing. Here, an original computational averaging scheme is developed for predicting the elastoplastic response of TRIP aided multiphase steels based on a strain gradient plasticity model. The microstructure is represented by an aggregate of many elementary unit cells involving each a fraction of retained austenite with a specified stability. The model parameters, involving the transformation kinetics, are identified based on experimental tensile tests performed at different temperatures. The model is further assessed towards original experiments, involving temperature changes during deformation. A classical size independent plasticity model is shown unable to capture the TRIP effect on the mechanical response. Conversely, the strain gradient formulation properly predicts substantial variations of the strain hardening with deformation and temperature, hence of the uniform elongation in good agreement with the experiments. A parametric study is performed to get more insight on the effect of the material length scale as well as to determine optimum transformation

  7. The effect of fuel rod oxidation on PCMI-induced fuel failure

    NASA Astrophysics Data System (ADS)

    Kim, Kyu-Tae

    2011-11-01

    It was found in a one of the PWRs operating in Korea that a few three cycle-burned Zry-4 fuel assemblies which were loaded in a core center region at control bank positions were leaking. The leaking cycle has experienced a few reactor trips and some fuel rods started to leak at about a month after a power ramp following the second reactor trip. To investigate a root cause of such fuel failure as well as to examine intact and leak rod oxidation behaviors, one intact and one leaking fuel rods were selected from one intact and one failed three cycle-burned fuel assemblies, respectively, and in parallel one intact fuel rod was selected from a two cycle-burned fuel assembly to examine the effect of burnup on fuel rod oxidation and cladding stress during the power ramp. The maximum oxide thicknesses for the intact two cycle-burned and three cycle-burned fuel rods were measured to be about 70 and 140 μm, respectively, whereas that for the leaking three cycle-burned fuel rod to be about 200 μm. The leaking fuel rods generated a very sharp increase in oxide thickness in the fuel rod upper region having a relatively high axial power, resulting in through-wall axial cracks. The root cause of the fuel rod leaks was evaluated to be the pellet-clad mechanical interaction (PCMI)-induced failure combined with excessive Zry-4 oxidation and cladding stress, based on the evaluations of pellet-clad friction coefficient-dependent cladding hoop stresses after the power ramp following the second trip, measured oxide thicknesses and axial cracks on the cladding surface, a fuel leak initiation time and failed fuel rod locations at the control bank positions.

  8. Field Trip.

    ERIC Educational Resources Information Center

    Sanders, Bill

    1993-01-01

    Reports the results of a field trip to measure the intensity of electromagnetic fields generated by electronic devices in the home, in cars, at work, outside, and in places people visit during the day. Found that a person gets more intense exposure while working at a computer than by living next to an electrical substation. (MDH)

  9. Maintaining a Critical Spectra within Monteburns for a Gas-Cooled Reactor Array by Way of Control Rod Manipulation

    SciTech Connect

    Adigun, Babatunde John; Fensin, Michael Lorne; Galloway, Jack D.; Trellue, Holly Renee

    2016-10-01

    Our burnup study examined the effect of a predicted critical control rod position on the nuclide predictability of several axial and radial locations within a 4×4 graphite moderated gas cooled reactor fuel cluster geometry. To achieve this, a control rod position estimator (CRPE) tool was developed within the framework of the linkage code Monteburns between the transport code MCNP and depletion code CINDER90, and four methodologies were proposed within the tool for maintaining criticality. Two of the proposed methods used an inverse multiplication approach - where the amount of fissile material in a set configuration is slowly altered until criticality is attained - in estimating the critical control rod position. Another method carried out several MCNP criticality calculations at different control rod positions, then used a linear fit to estimate the critical rod position. The final method used a second-order polynomial fit of several MCNP criticality calculations at different control rod positions to guess the critical rod position. The results showed that consistency in prediction of power densities as well as uranium and plutonium isotopics was mutual among methods within the CRPE tool that predicted critical position consistently well. Finall, while the CRPE tool is currently limited to manipulating a single control rod, future work could be geared toward implementing additional criticality search methodologies along with additional features.

  10. Maintaining a Critical Spectra within Monteburns for a Gas-Cooled Reactor Array by Way of Control Rod Manipulation

    DOE PAGES

    Adigun, Babatunde John; Fensin, Michael Lorne; Galloway, Jack D.; ...

    2016-10-01

    Our burnup study examined the effect of a predicted critical control rod position on the nuclide predictability of several axial and radial locations within a 4×4 graphite moderated gas cooled reactor fuel cluster geometry. To achieve this, a control rod position estimator (CRPE) tool was developed within the framework of the linkage code Monteburns between the transport code MCNP and depletion code CINDER90, and four methodologies were proposed within the tool for maintaining criticality. Two of the proposed methods used an inverse multiplication approach - where the amount of fissile material in a set configuration is slowly altered until criticalitymore » is attained - in estimating the critical control rod position. Another method carried out several MCNP criticality calculations at different control rod positions, then used a linear fit to estimate the critical rod position. The final method used a second-order polynomial fit of several MCNP criticality calculations at different control rod positions to guess the critical rod position. The results showed that consistency in prediction of power densities as well as uranium and plutonium isotopics was mutual among methods within the CRPE tool that predicted critical position consistently well. Finall, while the CRPE tool is currently limited to manipulating a single control rod, future work could be geared toward implementing additional criticality search methodologies along with additional features.« less

  11. Controlled self-assembly of conjugated rod-coil block copolymers for applications in organic optoelectronics

    NASA Astrophysics Data System (ADS)

    Tao, Yuefei

    Organic electronics are of great interest in manufacturing light weight, mechanical flexible, and inexpensive large area devices. While significant improvements have been made over the last several years and it is now clear that morphology on the lengthscale of exciton diffusion (10nm) is of crucial importance, a clear relationship between structure and device properties has not emerged. This lack of understanding largely emerges from an inability to control morphology on this lengthscale. This thesis will center around an approach, based on block copolymer self-assembly, to generate equilibrium nanostructures on the 10 nm lengthscale of exciton diffusion and study their effects on device performance. Self-assembly of semiconducting block copolymers is complicated by the non-classical chain shape of conjugated polymers. Unlike classical polymers, the chains do not assume a Gaussian coil shape which is stretched near block copolymer interfaces, instead the chains are elongated and liquid crystalline. Previous work has demonstrated how these new molecular interactions and shapes control the phase diagram of so-called rod-coil block copolymers. Here, we will focus on controlling domain size, orientation, and chemical structure. While domain size can be controlled directly through molecular weight, this requires significant additional synthesis of domain size is to be varied. Here, the domain size is controlled by blending homopolymers into a self-assembling rod-coil block copolymer. When coil-like blocks are incorporated, the domains swell, as expected. When rod-like blocks are incorporated, they interdigitate with the rods of the block copolymers. This results in an increase in interfacial area which forces the coils to rearrange and an overall decrease in domain size with increasing rod content. Control over lamellar orientation is crucial in order to design and control charge transport pathways and exciton recombination or separation interfaces. While numerous

  12. Contribution of the support limb in control of angular momentum after tripping.

    PubMed

    Pijnappels, Mirjam; Bobbert, Maarten F; van Dieën, Jaap H

    2004-12-01

    Tripping over an obstacle can result in a fall when the forward angular momentum, obtained from impact with the obstacle, is not arrested. Angular momentum can be restrained by proper placement of the recovery limb, anteriorly of the body, but possibly also by a reaction in the contralateral support limb during push-off. The purpose of this study was to quantify the extent to which the support limb contributes to recovery after tripping by providing time and clearance for proper positioning of the recovery limb, and by restraining the angular momentum of the body during push-off. Twelve young adults were repeatedly tripped over an obstacle during mid-swing, while walking over a platform. Kinematics and ground reaction forces at the support limb were measured. Quantification of the angular momentum was based on calculation of the external moment, which equals the rate of change in the angular momentum of the body. Results showed that all subjects acquired a similar increase in angular momentum during foot-obstacle contact, on average 11.4 kg m2s(-1). In all subjects, the support limb played a role in recovery after tripping by providing time and clearance for proper positioning of the recovery limb, as indicated by body elevation (6%) and the increased forward pelvis displacement over recovery stride (43%). Almost all subjects were also able to restrain the forward angular momentum of the body during push-off by the support limb. Less angular momentum remained to be further accomplished by the recovery limb. Reductions in the quality of the support limb responses may be among the factors that increase the risk of falling in the elderly.

  13. Simulation and operation of the EBR-2 automatic control rod drive system

    NASA Astrophysics Data System (ADS)

    Lehto, W. K.; Larson, H. A.; Dean, E. M.; Christensen, L. J.

    An automatic control rod drive system (ACRDS) installed at EBR-II produces shaped power transients from 40% to full reactor power at a linear ramp rate of 4 MWt/s. A digital computer and modified control rod drive provides this capability. Simulation and analysis of ACRDS experiments establish the safety envelope for reactor transient operation. Tailored transients are required as part of USDOE operational reliability testing program for prototypic fast reactor fuel cladding breach behavior studies. After initial EBR-II driver fuel testing and system checkout, test subassemblies were subjected to both slow and fast transients. In addition, the ACRDS is used for steady state operation and will be qualified to control power ascent from initial critical to full power.

  14. Cadmium control/safety rod disposal at the Savannah River Site

    SciTech Connect

    McInnis, S.H.

    1995-05-01

    Four heavy-water-moderated reactors at the Savannah River Site will undergo the removal of 862 activated cadmium control/safety rods. Although these reactors are 40 years old, they offer 4 basic advantages for decommissioning: the equipment is still in some sort of operable state; the reactor is blow the floor in a large process room, allowing access; Control/safety rods can be handled remotely by existing equipment; a radiologically shielded removal path exists. Drawbacks include the following: age of reactors; improvements in technology have caused incompatibility problems; more strigent standards; compliance with environmental regulations. This article details how the removal was carried out and the current status of the project, keeping in mind the above considerations.

  15. A model of the control rod housing overflow incident in a Savannah River Production Reactor

    SciTech Connect

    Shadday, M.A. Jr.; Flach, G.P.; Steimke, J.L.; Koffman, L.D.; Askew, N.M.

    1993-05-01

    On May 25, 1992, K-reactor at the Savannah River Site was being configured for start up when a D20 leak of unknown origin was detected on the top of the reactor. The reactor was immediately shutdown, and reactor start up was put on hold until the cause of the leak was determined and the problem eliminated. The source of the leak was suspected to be overflow of the control rod guide tubes, and on May 27 hydraulic tests in the laboratory confirmed this and identified the cause to be unanticipated secondary circulations in the control rod housings. The modelling effort, that in conjunction with the experimental program, identified a temporary fix that allowed K-reactor to be restarted two weeks after the initial overflow incident is herein described.

  16. Measurements of /sup 10/B(n,He) reaction rates in a mockup control rod in ZPPR

    SciTech Connect

    Brumbach, S.B.; Collins, P.J.; Oliver, B.M.

    1986-01-01

    This paper reports the first direct measurement of /sup 10/B capture rate in a mockup control rod in a critical assembly. The experiment used the helium accumulation fluence monitor (HAFM) technique. 13 refs.

  17. Controllable rotating behavior of individual dielectric micro-rod in a rotating electric field.

    PubMed

    Liu, Weiyu; Ren, Yukun; Tao, Ye; Li, Yanbo; Chen, Xiaoming

    2017-02-18

    We report herein controllable rotating behavior of an individual dielectric micro-rod driven by a background rotating electric field. By disposing or removing structured floating microelectrode, the rigid rod suspended in electrolyte solution accordingly exhibits co-field or anti-field rotating motion. In the absence of the ideally polarizable metal surface, the dielectric rod rotates opposite to propagation of electric field, with the measured rotating rate much larger than predicted by Maxwell-Wager interfacial polarization theory incorporating surface conduction of fixed bond charge. Surprisingly, with floating electrode embedded, a novel kind of co-field rotation mode occurs in the presence of induced double-layer polarization, due to the action of hydrodynamic torque from rotating induced-charge electroosmosis. This method of achieving switchable spin modes of dielectric particles would direct implications in constructing flexible electrokinetic framework for analyzing 3D profile of on-chip bio-microfluidic samples. This article is protected by copyright. All rights reserved.

  18. The use of magnetically controlled growing rod device for pediatric scoliosis

    PubMed Central

    Figueiredo, Nicandro; Kananeh, Salman F.; Siqueira, Heloise H.; Figueiredo, Rita C.; Al Sebai, Mohamed W.

    2016-01-01

    Objective: To study the safety and efficacy of an innovative device using distraction-based magnetically controlled growing rods (MCGR) for the treatment of pediatric scoliosis. Methods: This is an evidence-based systematic review of literature for the surgical management of patients with pediatric scoliosis using MCGR technique. Six clinical studies regarding the use of MCGR were included in this review, with a total of 68 patients, and mean age of 8.38 years. The dual-rod (DR) technique of rod construct with MCGR was used in 33.85% and the single-rod (SR) in 66.15% of the patients. Results: The mean preoperative main coronal curve for the DR was 65.9°, and for the SR was 69.6° (p>0.05). At the latest follow-up, it was 36.8° for DR and 43.0° for SR (p<0.05). The mean preoperative T1-S1 spinal length was 298.7 mm for the DR and 303.5 mm for the SR group (p<0.05). According to the latest follow-up, using the DR construct, the spinal length increased to 347 mm with 13.92% of total lengthening; and using the SR construct, the average lengthening was 339 mm, with 10.48% of total lengthening (p<0.05). Postoperative complications were similar, 25% in DR and 31.57% in the SR group (p>0.05). Conclusion: Level IV of medical evidence supports the use of MCGR as a safe and effective alternative for the treatment of severe pediatric scoliosis. Recommendation Grade C supports the role of MCGR with DR construct as an option to achieve a better correction of the scoliotic curve and to maximize the postoperative T1-S1 spinal length. PMID:26818162

  19. Microstructural engineering applied to the controlled cooling of steel wire rod: Part I. Experimental design and heat transfer

    NASA Astrophysics Data System (ADS)

    Campbell, P. C.; Hawbolt, E. B.; Brimacombe, J. K.

    1991-11-01

    The goal of this study was to develop a mathematical model which incorporates heat flow, phase transformation kinetics, and property-structure-composition relationships to predict the mechanical properties of steel rod being control cooled under industrial conditions. Thus, the principles of microstructural engineering have been brought to bear on this interdisciplinary problem by combining computer modeling with laboratory measurements of heat flow, austenite decomposition kinetics, microstructure and mechanical properties, and industrial trials to determine heat transfer and obtain rod samples under known conditions. Owing to the length and diversity of the study, it is reported in three parts,[8191]the first of which is concerned with the heat flow measurements. A relatively simple and reliable technique, involving a preheated steel rod instrumented with a thermocouple secured at its centerline, has been devised to determine the cooling rate in different regions of the moving bed of rod loops on an operating Stelmor line. The measured thermal response of the rod has been analyzed by two transient conduction models (lumped and distributed parameter, respectively) to yield overall heat-transfer coefficients for radiation and convection. The adequacy of the technique has been checked by cooling instrumented rods under well-defined, air crossflow conditions in the laboratory and comparing measured heat-transfer coefficients to values predicted from well-established equations. The industrial thermal measurements have permitted the characterization of a coefficient to account for radiative interaction among adjacent rod loops near the edge and at the center of the bed.

  20. Analyses of eigenvalue bias and control rod worths in FFTF (Fast Flux Test Facility)

    SciTech Connect

    Nelson, J.V.; Dobbin, K.D.; Wootan, D.W.; Campbell, L.R.

    1987-01-01

    The Fast Flux Test Facility (FFTF) core loading during its ninth operating cycle was significantly different from that of previous cycles because of the presence of the Core Demonstration Experiment (CDE). The CDE consists of a number of axially blanketed fuel assemblies and internal blankets prototypic of advanced oxide cores in Liquid Metal Reactors (LMR). In preparation for the Cycle 9 reload design effort, a careful assessment of control rod worth and reactivity calculations for Cycles 1 through 8 was made. The goal of this study was to establish calculational biases and reduce uncertainties factored into the reload design calculations. These analyses helped assure that the operational objectives for Cycle 9 were met.

  1. Microstructural engineering applied to the controlled cooling of steel wire rod: Part III. Mathematical model-formulation and predictions

    NASA Astrophysics Data System (ADS)

    Campbell, P. C.; Hawbolt, E. B.; Brimacombe, J. K.

    1991-11-01

    In this final part of the study, a mathematical model incorporating heat flow, microstructural phenomena, and structure-composition-mechanical property relationships has been developed to compute the yield strength (YS) and ultimate tensile strength (UTS) of steel rod control cooled on a Stelmor line. The predictive capability of the model, in terms of temperature response, microstructural evolution, and strength of the rods, has been tested by comparison to measurements from an extensive set of laboratory and plant trials. Thus, the model has been shown to simulate the complex heat flow and microstructural phenomena in the steel rod very well, although improvements need to be sought in the characterization of the austenite-ferrite transformation kinetics and of pearlite interlamellar spacing. The latter variable has a significant influence on the strength of eutectoid steels. Nonetheless, the model consistently is capable of predicting the strengths of plain-carbon steel rods ranging from 1020 to 1080 to within ± 10 pet.

  2. Cost analysis of magnetically controlled growing rods compared with traditional growing rods for early-onset scoliosis in the US: an integrated health care delivery system perspective

    PubMed Central

    Polly, David W; Ackerman, Stacey J; Schneider, Karen; Pawelek, Jeff B; Akbarnia, Behrooz A

    2016-01-01

    Purpose Traditional growing rod (TGR) for early-onset scoliosis (EOS) is effective but requires repeated invasive surgical lengthenings under general anesthesia. Magnetically controlled growing rod (MCGR) is lengthened noninvasively using a hand-held magnetic external remote controller in a physician office; however, the MCGR implant is expensive, and the cumulative cost savings have not been well studied. We compared direct medical costs of MCGR and TGR for EOS from the US integrated health care delivery system perspective. We hypothesized that over time, the MCGR implant cost will be offset by eliminating repeated TGR surgical lengthenings. Methods For both TGR and MCGR, the economic model estimated the cumulative costs for initial implantation, lengthenings, revisions due to device failure, surgical-site infections, device exchanges (at 3.8 years), and final fusion, over a 6-year episode of care. Model parameters were estimated from published literature, a multicenter EOS database of US institutions, and interviews. Costs were discounted at 3.0% annually and represent 2015 US dollars. Results Of 1,000 simulated patients over 6 years, MCGR was associated with an estimated 270 fewer deep surgical-site infections and 197 fewer revisions due to device failure compared with TGR. MCGR was projected to cost an additional $61 per patient over the 6-year episode of care compared with TGR. Sensitivity analyses indicated that the results were sensitive to changes in the percentage of MCGR dual rod use, months between TGR lengthenings, percentage of hospital inpatient (vs outpatient) TGR lengthenings, and MCGR implant cost. Conclusion Cost neutrality of MCGR to TGR was achieved over the 6-year episode of care by eliminating repeated TGR surgical lengthenings. To our knowledge, this is the first cost analysis comparing MCGR to TGR – from the US provider perspective – which demonstrates the efficient provision of care with MCGR. PMID:27695352

  3. STABILIZED RARE EARTH OXIDES FOR A CONTROL ROD AND METHOD OF PREPARATION

    DOEpatents

    McNees, R.A.; Potter, R.A.

    1964-01-14

    A method is given for preparing mixed oxides of the formula MR/sub x/O/ sub 12/ wherein M is tungsten or molybdenum and R is a rare earth in the group consisting of samarium, europium, dysprosium, and gadolinium and x is 4 to 5. Oxides of this formula, and particularly the europiumcontaining species, are useful as control rod material for water-cooled nuclear reactors owing to their stability, favorable nuclear properties, and resistance to hydration. These oxides may be utilized as a dispersion in a stainlesssteel matrix. Preparation of these oxides is effected by blending tungsten oxide or molybdenum oxide with a rare earth oxide, compressing the mixture, and firing at an elevated temperature in an oxygen-containing atmosphere. (AEC)

  4. Research relative to an advanced rod control system for quadrupole mass spectrometry applications

    NASA Technical Reports Server (NTRS)

    Carignan, George R.

    1987-01-01

    The design of a suitable amplifier output stage using available transistors and passive components is summarized. All of the analysis and calculation confirm that it is feasible to design the amplifier and quadrupole coupling circuit needed for the Advanced Rod Control System. The progress obtained so far concerning the three frequency tank circuits to be used in the oscillator for the mass spectrometer of the Cometary Rendezvous Asteroid Flyby (CRAF) project is presented. Results from this study look promising. However, it is not known what minimum impedance levels are required to make it possible for the oscillator to work properly. Therefore, it is necessary to construct a prototype circuit in the laboratory which can be measured and tested in an oscillator circuit. Continued attempts will be made to develop a useful inductor motor with better characteristics than the one being used at the moment. It is important that such a model be found if computer simulation is to reflect reality more closely.

  5. Control of Prestressing Force in Rod for Reducing Bending in Beams

    NASA Astrophysics Data System (ADS)

    Wong, M. B.

    2010-05-01

    This paper presents a method to determine the prestressing force required in a rod for reducing the bending effects in a beam. The rod is positioned underneath the beam such that the prestressing force is counteracting the effects of beam bending. It has been found that the prestressing force may also increase the bending as a result of P-δ effect. Therefore, the choice of both the prestressing force and the rod eccentricity from the beam axis is important in determining the appropriate actions to resist the bending of the beam. Over-prestressing the rod may even induce bending or buckling failure in the beam in the reverse direction.

  6. 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.

  7. The DBA Analysis of One Control Rod Withdrawal Out of the HTR-10GT Core

    SciTech Connect

    Mingang Lang; Yujie Dong

    2006-07-01

    The 10 MW High Temperature Gas Cooled Test Reactor (HTR-10) has been built in Institute of Nuclear and New Energy Technology (INET) and has been operating successfully since the beginning of 2003. The core outlet temperature of HTR-10 is 700 deg. C. To verify the technology of gas-turbine direct cycle, INET has planned to increase its core outlet temperature to 750 deg. C and use a helium gas turbine instead of the steam generator (then the reactor is called HTR-10GT). Though HTR-10 has good intrinsic safety, the design basic accidents and beyond design basic accidents of HTR10-GT must be analyzed according to China's nuclear regulations due to changed operation parameters. THERMIX code system is used to study the accident on one control rod withdrawal out of the core by a mistake. After a control rod in the side reflector was withdrawn out at a speed of 1 cm/s by a mistake, a positive reactivity was inserted and the reactor power increased and the temperature of the core increased. When the neutron flux of power measuring range exceeded 123% and the core outlet temperature was lager than 800 deg. C, the reactor was scrammed. During the accident sequence the maximum fuel temperature was 1200.9 deg. C. It was lower than the fuel temperature limitation of 1230 deg. C. The paper compares the analysis result of HTR10-GT to those of HTR-10. The results shows that the HTR-10GT is still safe during the accident though its operating temperature is higher than HTR-10 when the fuel safety limits are the same. (authors)

  8. Planning a Field Trip

    ERIC Educational Resources Information Center

    Forecast for Home Economics, 1975

    1975-01-01

    The showroom of a button manufacturer was the site of a successful field trip for a New York City home economics class. Suggestions for field trip preparation are included as well as directions for making button jewelry. (EA)

  9. 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

  10. Photostimulator allowing independent control of rods and the three cone types.

    PubMed

    Pokorny, Joel; Smithson, Hannah; Quinlan, Jules

    2004-01-01

    This report describes a second-generation photostimulator with four primary lights that allows independent control of the stimulation of the four receptor types in the human eye. The new design uses LEDs (with light levels controlled by eight drivers that include voltage-to-frequency converters that provide 1-micros pulses at frequencies up to 250 kHz), with four center channels being combined by use of a fiber optic assembly, and likewise for four surround channels. Four fiber optic bundles are merged into a single bundle whose output is fed into a spatial homogenizer terminated by a diffuser. An interference filter is sandwiched between each LED and the fiber optic bundle. Two camera lenses collimate light from the diffusers, one for center and one for surround. The center-surround field configuration is formed by a photometric cube with a mirrored ellipse on the hypotenuse. A field lens places images of the diffusers in the plane of an artificial pupil. The fields are highly uniform. Following alignment and calibration, the center and surround fields are indistinguishable. An observer calibration procedure, designed to compensate for prereceptoral filtering, is shown by calculation to correct also for normal observer receptoral spectral sensitivity variation. With the instrument calibrated for the individual observer, a peripherally fixated 200-ms 40% contrast rod center field pulse, highly conspicuous under dark adaptation, is invisible following light adaptation.

  11. Effective parameter study for the facile and controlled growth of silver molybdate nano/micro rods

    NASA Astrophysics Data System (ADS)

    Montenegro, Javier Esteban Enríquez; Singh, Dinesh Pratap

    2016-11-01

    Controlled growth of nano/micro structures by controlling the effective parameters is the basic requirement for the application point of view in various areas. Here we report the facile growth of silver molybdate nano/micro rods by mixing the solution of silver nitrate and ammonium molybdate at ambient condition followed by hydrothermal treatment at various temperatures for 12 h. To achieve the goal for the synthesis of long, high yield and homogeneous nanorods various effective parameters have been studied to set the most effective conditions for the growth. Among possible effective parameters first the temperature of the furnace was set by warring the temperature and then at the set temperature the concentration of reactants (NH4)6Mo7O24 and silver nitrate are varied respect to each other. The pH and temperature values were monitored during the mixing of the reactants. Structural/microstructural characterization revealed the optimum condition of 150°C of the furnace and the concentration of (NH4)6Mo7O24 and silver nitrate as described in various tables.

  12. Thermo-Mechanical Analysis of Coated Particle Fuel Experiencing a Fast Control Rod Ejection Transient

    SciTech Connect

    Ortensi, J.; Brian Boer; Abderrafi M. Ougouag

    2010-10-01

    A rapid increase of the temperature and the mechanical stress is expected in TRISO coated particle fuel that experiences a fast Total Control Rod Ejection (CRE) transient event. During this event the reactor power in the pebble bed core increases significantly for a short time interval. The power is deposited instantly and locally in the fuel kernel. This could result in a rapid increase of the pressure in the buffer layer of the coated fuel particle and, consequently, in an increase of the coating stresses. These stresses determine the mechanical failure probability of the coatings, which serve as the containment of radioactive fission products in the Pebble Bed Reactor (PBR). A new calculation procedure has been implemented at the Idaho National Laboratory (INL), which analyzes the transient fuel performance behavior of TRISO fuel particles in PBRs. This early capability can easily be extended to prismatic designs, given the availability of neutronic and thermal-fluid solvers. The full-core coupled neutronic and thermal-fluid analysis has been modeled with CYNOD-THERMIX. The temperature fields for the fuel kernel and the particle coatings, as well as the gas pressures in the buffer layer, are calculated with the THETRIS module explicitly during the transient calculation. Results from this module are part of the feedback loop within the neutronic-thermal fluid iterations performed for each time step. The temperature and internal pressure values for each pebble type in each region of the core are then input to the PArticle STress Analysis (PASTA) code, which determines the particle coating stresses and the fraction of failed particles. This paper presents an investigation of a Total Control Rod Ejection (TCRE) incident in the 400 MWth Pebble Bed Modular reactor design using the above described calculation procedure. The transient corresponds to a reactivity insertion of $3 (~2000 pcm) reaching 35 times the nominal power in 0.5 seconds. For each position in the core

  13. Development of a HTSMA-Actuated Surge Control Rod for High-Temperature Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    Padula, Santo, II; Noebe, Ronald; Bigelow, Glen; Culley, Dennis; Stevens, Mark; Penney, Nicholas; Gaydosh, Darrell; Quackenbush, Todd; Carpenter, Bernie

    2007-01-01

    In recent years, a demand for compact, lightweight, solid-state actuation systems has emerged, driven in part by the needs of the aeronautics industry. However, most actuation systems used in turbomachinery require not only elevated temperature but high-force capability. As a result, shape memory alloy (SMA) based systems have worked their way to the forefront of a short list of viable options to meet such a technological challenge. Most of the effort centered on shape memory systems to date has involved binary NiTi alloys but the working temperatures required in many aeronautics applications dictate significantly higher transformation temperatures than the binary systems can provide. Hence, a high temperature shape memory alloy (HTSMA) based on NiTiPdPt, having a transformation temperature near 300 C, was developed. Various thermo-mechanical processing schemes were utilized to further improve the dimensional stability of the alloy and it was later extruded/drawn into wire form to be more compatible with envisioned applications. Mechanical testing on the finished wire form showed reasonable work output capability with excellent dimensional stability. Subsequently, the wire form of the alloy was incorporated into a benchtop system, which was shown to provide the necessary stroke requirements of approx.0.125 inches for the targeted surge-control application. Cycle times for the actuator were limited to 4 seconds due to control and cooling constraints but this cycle time was determined to be adequate for the surge control application targeted as the primary requirement was initial actuation of a surge control rod, which could be completed in approximately one second.

  14. Assessment of the mechanical performance of the Westinghouse BWR control rod CR 99 at high depletion levels

    SciTech Connect

    Seltborg, P.; Jinnestrand, M.

    2012-07-01

    A long-term program assessing the mechanical performance of the Westinghouse BWR control rod CR 99 at high depletion levels has been performed. The scope of the program has mainly been based on the operation of four CR 99 Generation 2 control rods in demanding positions during 6 and 7 cycles in the Leibstadt Nuclear Power Plant (KKL) and on the detailed visual inspections and blade wing thickness measurements that were performed after the rods were discharged. By correlating statistically the blade wing thickness measurements to the appearance of irradiation-assisted stress corrosion cracking (IASCC), the probability of IASCC appearance as function of the blade wing swelling was estimated. In order to correlate the IASCC probability of a CR 99 to its depletion, the {sup 10}B depletion of the studied rods was calculated in detail on a local level with the stochastic Monte Carlo code MCNP in combination with the Westinghouse nodal code system PHOENIX4/POLCA7. Using this information coupled to the blade wing measurement data, a finite element model describing the blade wing swelling of an arbitrary CR 99 design as function of {sup 10}B depletion could then be generated. In the final step, these relationships were used to quantify the probability of IASCC appearance as function of the {sup 10}B depletion of the CR 99 Generations 2 and 3. Applying this detailed mapping of the CR 99 behavior at high depletion levels and using an on-line core monitoring system with explicit {sup 10}B depletion tracking capabilities will enable a reliable prediction of the probability for IASCC appearance, thus enhancing the optimized design and the sound operation of the CR 99 control rod. Another important outcome of the program was that it was clearly shown that no significant amount of boron leakage did occur through any of the detected IASCC cracks, despite the very high depletion levels achieved. (authors)

  15. Disposal Of Irradiated Cadmium Control Rods From The Plumbrook Reactor Facility

    SciTech Connect

    Posivak, E.J.; Berger, S.R.; Freitag, A.A.

    2008-07-01

    Innovative mixed waste disposition from NASA's Plum Brook Reactor Facility was accomplished without costly repackaging. Irradiated characteristic hardware with contact dose rates as high as 8 Sv/hr was packaged in a HDPE overpack and stored in a Secure Environmental Container during earlier decommissioning efforts, awaiting identification of a suitable pathway. WMG obtained regulatory concurrence that the existing overpack would serve as the macro-encapsulant per 40CFR268.45 Table 1.C. The overpack vent was disabled and the overpack was placed in a stainless steel liner to satisfy overburden slumping requirements. The liner was sealed and placed in shielded shoring for transport to the disposal site in a US DOT Type A cask. Disposition via this innovative method avoided cost, risk, and dose associated with repackaging the high dose irradiated characteristic hardware. In conclusion: WMG accomplished what others said could not be done. Large D and D contractors advised NASA that the cadmium control rods could only be shipped to the proposed Yucca mountain repository. NASA management challenged MOTA to find a more realistic alternative. NASA and MOTA turned to WMG to develop a methodology to disposition the 'hot and nasty' waste that presumably had no path forward. Although WMG lead a team that accomplished the 'impossible', the project could not have been completed with out the patient, supportive management by DOE-EM, NASA, and MOTA. (authors)

  16. Seasonal and Weather Effects on Older Drivers' Trip Distances.

    PubMed

    Smith, Glenys A; Porter, Michelle M; Cull, Andrew W; Mazer, Barbara L; Myers, Anita M; Naglie, Gary; Bédard, Michel; Tuokko, Holly A; Vrkljan, Brenda H; Gélinas, Isabelle; Marshall, Shawn C; Rapoport, Mark J

    2016-04-05

    The purpose of this study was to determine if season or weather affected the objectively measured trip distances of older drivers (≥ 70 years; n = 279) at seven Canadian sites. During winter, for all trips taken, trip distance was 7 per cent shorter when controlling for site and whether the trip occurred during the day. In addition, for trips taken within city limits, trip distance was 1 per cent shorter during winter and 5 per cent longer during rain when compared to no precipitation when controlling for weather (or season respectively), time of day, and site. At night, trip distance was about 30 per cent longer when controlling for season and site (and weather), contrary to expectations. Together, these results suggest that older Canadian drivers alter their trip distances based on season, weather conditions, and time of day, although not always in the expected direction.

  17. Genetic algorithm based active vibration control for a moving flexible smart beam driven by a pneumatic rod cylinder

    NASA Astrophysics Data System (ADS)

    Qiu, Zhi-cheng; Shi, Ming-li; Wang, Bin; Xie, Zhuo-wei

    2012-05-01

    A rod cylinder based pneumatic driving scheme is proposed to suppress the vibration of a flexible smart beam. Pulse code modulation (PCM) method is employed to control the motion of the cylinder's piston rod for simultaneous positioning and vibration suppression. Firstly, the system dynamics model is derived using Hamilton principle. Its standard state-space representation is obtained for characteristic analysis, controller design, and simulation. Secondly, a genetic algorithm (GA) is applied to optimize and tune the control gain parameters adaptively based on the specific performance index. Numerical simulations are performed on the pneumatic driving elastic beam system, using the established model and controller with tuned gains by GA optimization process. Finally, an experimental setup for the flexible beam driven by a pneumatic rod cylinder is constructed. Experiments for suppressing vibrations of the flexible beam are conducted. Theoretical analysis, numerical simulation and experimental results demonstrate that the proposed pneumatic drive scheme and the adopted control algorithms are feasible. The large amplitude vibration of the first bending mode can be suppressed effectively.

  18. Controlling chaos based on a novel intelligent integral terminal sliding mode control in a rod-type plasma torch

    NASA Astrophysics Data System (ADS)

    Safa, Khari; Zahra, Rahmani; Behrooz, Rezaie

    2016-05-01

    An integral terminal sliding mode controller is proposed in order to control chaos in a rod-type plasma torch system. In this method, a new sliding surface is defined based on a combination of the conventional sliding surface in terminal sliding mode control and a nonlinear function of the integral of the system states. It is assumed that the dynamics of a chaotic system are unknown and also the system is exposed to disturbance and unstructured uncertainty. To achieve a chattering-free and high-speed response for such an unknown system, an adaptive neuro-fuzzy inference system is utilized in the next step to approximate the unknown part of the nonlinear dynamics. Then, the proposed integral terminal sliding mode controller stabilizes the approximated system based on Lyapunov’s stability theory. In addition, a Bee algorithm is used to select the coefficients of integral terminal sliding mode controller to improve the performance of the proposed method. Simulation results demonstrate the improvement in the response speed, chattering rejection, transient response, and robustness against uncertainties.

  19. Measuring the efficiency of control rods in the RBMK critical assembly using a model of RKI-1 reactimeter

    NASA Astrophysics Data System (ADS)

    Zhitarev, V. E.; Lebedev, G. V.; Sergevnin, A. Yu.

    2016-12-01

    The efficiency of control rods of the RBMK critical assembly is measured in a series of experiments. The aim of measurements is to determine the characteristics of the model of an RKI-1 reactimeter. The RKI-1 reactimeter is intended for measuring the efficiency of control rods when, according to conditions of operation, the metrological certification of results of an experiment is required. Complications with the metrological certification of reactimeters arise owing to the fact that usually calculated corrections to the results of measurements are required. When the RKI-1 reactimeter is used, there is no need to introduce calculated corrections; the result of measurements is given with the indication of substantiated errors. In connection with this, the metrological certification of the results of measurements using the RKI-1 reactimeter is simplified.

  20. Analysis of the dose rate produced by control rods discharged from a BWR into the irradiated fuel pool.

    PubMed

    Ródenas, J; Gallardo, S; Abarca, A; Juan, V

    2010-01-01

    BWR control rods become activated by neutron reactions into the reactor. Therefore, when they are withdrawn from the reactor, they must be stored into the storage pool for irradiated fuel at a certain depth under water. Dose rates on the pool surface and the area surrounding the pool should be lower than limits for workers. The MCNP code based on the Monte Carlo method has been applied to model this situation and to calculate dose rates at points of interest.

  1. Trade, TRIPS, and pharmaceuticals.

    PubMed

    Smith, Richard D; Correa, Carlos; Oh, Cecilia

    2009-02-21

    The World Trade Organization's Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) set global minimum standards for the protection of intellectual property, substantially increasing and expanding intellectual-property rights, and generated clear gains for the pharmaceutical industry and the developed world. The question of whether TRIPS generates gains for developing countries, in the form of increased exports, is addressed in this paper through consideration of the importance of pharmaceuticals in health-care trade, outlining the essential requirements, implications, and issues related to TRIPS, and TRIPS-plus, in which increased restrictions are imposed as part of bilateral free-trade agreements. TRIPS has not generated substantial gains for developing countries, but has further increased pharmaceutical trade in developed countries. The unequal trade between developed and developing countries (ie, exporting and importing high-value patented drugs, respectively) raises the issue of access to medicines, which is exacerbated by TRIPS-plus provisions, although many countries have not even enacted provision for TRIPS flexibilities. Therefore this paper focuses on options that are available to the health community for negotiation to their advantage under TRIPS, and within the presence of TRIPS-plus.

  2. Calculation of the Phenix end-of-life test 'Control Rod Withdrawal' with the ERANOS code

    SciTech Connect

    Tiberi, V.

    2012-07-01

    The Inst. of Radiological Protection and Nuclear Safety (IRSN) acts as technical support to French public authorities. As such, IRSN is in charge of safety assessment of operating and under construction reactors, as well as future projects. In this framework, one current objective of IRSN is to evaluate the ability and accuracy of numerical tools to foresee consequences of accidents. Neutronic studies step in the safety assessment from different points of view among which the core design and its protection system. They are necessary to evaluate the core behavior in case of accident in order to assess the integrity of the first barrier and the absence of a prompt criticality risk. To reach this objective one main physical quantity has to be evaluated accurately: the neutronic power distribution in core during whole reactor lifetime. Phenix end of life tests, carried out in 2009, aim at increasing the experience feedback on sodium cooled fast reactors. These experiments have been done in the framework of the development of the 4. generation of nuclear reactors. Ten tests have been carried out: 6 on neutronic and fuel aspects, 2 on thermal hydraulics and 2 for the emergency shutdown. Two of them have been chosen for an international exercise on thermal hydraulics and neutronics in the frame of an IAEA Coordinated Research Project. Concerning neutronics, the Control Rod Withdrawal test is relevant for safety because it allows evaluating the capability of calculation tools to compute the radial power distribution on fast reactors core configurations in which the flux field is very deformed. IRSN participated to this benchmark with the ERANOS code developed by CEA for fast reactors studies. This paper presents the results obtained in the framework of the benchmark activity. A relatively good agreement was found with available measures considering the approximations done in the modeling. The work underlines the importance of burn-up calculations in order to have a fine

  3. A Biomes Field Trip.

    ERIC Educational Resources Information Center

    Leonard, William H.; And Others

    1983-01-01

    Describes a field trip designed to give students opportunities to experience relevant data leading to concepts in biogeography. Suggests that teachers (including college instructors) adapt the areas studied and procedures used to their own locations. Includes a suggested field trip handout. (JN)

  4. BOCES Field Trip Guide.

    ERIC Educational Resources Information Center

    Nassau County Board of Cooperative Educational Services, Westbury, NY.

    An effective and comprehensive guide to possible field trips for Nassau County (New York) elementary and secondary students covers places of interest in Nassau and Suffolk counties and in New York City. Recognizing that field trips can have great importance in the learning process, especially if they are directly related to the curriculum, the…

  5. Geological Field Trip Guidebooks

    ERIC Educational Resources Information Center

    Wallace, Harriet E.

    1978-01-01

    Geological field trip guidebooks, developed for use during a field trip or field conference, are considered ephemeral publications by their compilers and publishers. Too few copies are printed and little attention is paid to bibliographic format and information. These difficulties are discussed and recommendations are made to alleviate the…

  6. 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.

  7. Enhancement of the 77 K critical currents on thin textured Bi-2212 rods by controlled distribution of secondary phases

    NASA Astrophysics Data System (ADS)

    Natividad, E.; Angurel, L. A.; Díez, J. C.; Navarro, R.; Martínez, E.; Yang, Y.; Beduz, C.

    2002-08-01

    Long and thin Bi-2212 rods textured by laser induced zone melting show inhomogeneous radial distribution of secondary phases and Bi concentration in transverse cross-sections. The microstructure inhomogeneity, which depends on the growth conditions, is reflected in the physical properties of the samples. We have estimated the radial distribution of Jc (77 K) in different samples using destructive and non-destructive approaches, correlating these results with the microstructure variations. Using this knowledge, the conductor performance at 77 K has been optimised by controlling the distribution of secondary phases.

  8. Nondestructive and Destructive Examination Studies on Removed-from-Service Control Rod Drive Mechanism Penetrations

    SciTech Connect

    Cumblidge, Stephen E.; Crawford, Susan L.; Doctor, Steven R.; Seffens, Rob J.; Schuster, George J.; Toloczko, Mychailo B.; Harris, Robert V.; Bruemmer, Stephen M.

    2007-06-07

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objectives of this work are to provide information to the U.S. Nuclear Regulatory Commission (NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. Two CRDM assemblies were removed from service, decontaminated, and then used in a series of NDE and destructive examination (DE) measurements; this report addresses the following questions: 1) What did each NDE technique detect? 2) What did each NDE technique miss? 3) How accurately did each NDE technique characterize the detected flaws? 4) Why did the NDE techniques perform or not perform? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. This report focuses on a CRDM assembly that contained suspected PWSCC, based on in-service inspection data and through-wall leakage. The NDE measurements used to examine the CRDM assembly followed standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. These techniques included eddy current testing (ET), time-of-flight diffraction ultrasound, and penetrant testing. In addition, laboratory-based NDE methods were employed to conduct inspections of the CRDM assembly with particular emphasis on inspecting the J-groove weld and buttering. These techniques included volumetric ultrasonic inspection of the J-groove weld metal and visual testing via replicant material of the J-groove weld. The results from these NDE studies were used to

  9. Field Trips: Tradition in Jeopardy

    ERIC Educational Resources Information Center

    Wheeler, Ginger

    2011-01-01

    The school field trip: something fun, different, exciting, exhausting--a break from the school day grind. But the field trip has ramifications beyond just getting out of school for the day. For students, the field trip is to the classroom what the big game is to athletes. For museums and other attractions, the field trip is a way to cultivate…

  10. 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.

  11. Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

    DOEpatents

    Thomas, G.; Ahn, J.H.; Kim, N.J.

    1986-10-28

    An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar[sub 3] temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics. 3 figs.

  12. Controlled rolling process for dual phase steels and application to rod, wire, sheet and other shapes

    DOEpatents

    Thomas, Gareth; Ahn, Jae-Hwan; Kim, Nack-Joon

    1986-01-01

    An improved, energy efficient, hot rolling method for direct production of cold formable dual-phase steel is provided. The steel is heated to completely austenitize it and then continuously hot rolled and cooled down into the ferrite-austenite two phase region to a temperature which is just below the effective Ar.sub.3 temperature. The hot rolled steel is then rapidly quenched to provide an alloy containing strong, tough lath martensite (fibers) in a ductile soft ferrite matrix. The method is particularly useful for providing rods in which form the alloy is capable of being drawn into high strength wire or the like in a cold drawing operation without any intermediate annealing or patenting, and has excellent strength, ductility and fatigue characteristics.

  13. The Effects of Autonomy-Supportive vs. Controlling Guidance on Learners' Motivational and Cognitive Achievement in a Structured Field Trip

    ERIC Educational Resources Information Center

    Basten, Melanie; Meyer-Ahrens, Inga; Fries, Stefan; Wilde, Matthias

    2014-01-01

    Field trips can provide unique opportunities for authentic, meaningful, and self-determined learning. Capitalizing on these opportunities requires that field trips be structured. A common way to do this is through the use of educational materials such as worksheets. The extent to which the guide's or teacher's autonomy-supportive or…

  14. Size-controlled synthesis of rod-like α-FeOOH nanostructure.

    PubMed

    Wei, Chengzhen; Qiao, Penghui; Nan, Zhaodong

    2012-08-01

    One-dimensional goethite (α-FeOOH) nanorods were successfully fabricated by a hydrothermal route without any template. Experimental results reveal that concentrations of Fe(3+) and ethylenediaminetetraacetic disodium salt (Na2EDTA) affect the phase composition and size of the as-synthesized products. The size of the rod-like α-FeOOH increased when the concentration of Na2EDTA was increased, where Na2EDTA acts as a nucleation inhibitor. α-Fe2O3 nanoparticles were produced when the concentration of Fe(3+) was increased from 0.02 to 0.08 and 0.40 M. A possible formation mechanism was proposed based on the results of the time dependent experiments. Different electrolytes and surfactants can affect the size and the aspect ratio of the as-prepared nanorod-like α-FeOOH. Na2SO4 induced the decreasing of the size of the as-prepared sample. KCl and PVP affected the aspect ratio of the nanorods.

  15. Benchmark of Atucha-2 PHWR RELAP5-3D control rod model by Monte Carlo MCNP5 core calculation

    SciTech Connect

    Pecchia, M.; D'Auria, F.; Mazzantini, O.

    2012-07-01

    Atucha-2 is a Siemens-designed PHWR reactor under construction in the Republic of Argentina. Its geometrical complexity and peculiarities require the adoption of advanced Monte Carlo codes for performing realistic neutronic simulations. Therefore core models of Atucha-2 PHWR were developed using MCNP5. In this work a methodology was set up to collect the flux in the hexagonal mesh by which the Atucha-2 core is represented. The scope of this activity is to evaluate the effect of obliquely inserted control rod on neutron flux in order to validate the RELAP5-3D{sup C}/NESTLE three dimensional neutron kinetic coupled thermal-hydraulic model, applied by GRNSPG/UNIPI for performing selected transients of Chapter 15 FSAR of Atucha-2. (authors)

  16. Condensate microdrop self-propelling aluminum surfaces based on controllable fabrication of alumina rod-capped nanopores.

    PubMed

    Zhao, Ye; Luo, Yuting; Li, Juan; Yin, Fei; Zhu, Jie; Gao, Xuefeng

    2015-06-03

    Here, we report a type of aluminum-based condensate microdrop self-propelling (CMDSP) functional films based on the controllable fabrication of anodic alumina rod-capped nanopores, which can be realized by a three-step method based on the skillful combinations of well-established hard anodization, mild anodization and chemical etching techniques. Such a surface nanoengineering strategy is verified to be feasible via our exemplified experiments and scanning electronic microscopy characterizations. After fluorosilane modification, the surface nanostructure can induce the efficient self-jumping of small-scale condensate microdrops, especially below 50 μm. This work offers an avenue for developing CMDSP aluminum surfaces with self-cleaning, antifrosting, and antidewing functions.

  17. Evaluation and Repair of Primary Water Stress Corrosion Cracking in Alloy 600/182 Control Rod Drive Mechanism Nozzles

    SciTech Connect

    Frye, Charles R.; Arey, Melvin L. Jr.; Robinson, Michael R.; Whitaker, David E.

    2002-07-01

    In February 2001, a routine visual inspection of the reactor vessel head of Oconee Nuclear Station Unit 3 identified boric acid crystals at nine of sixty-nine locations where control rod drive mechanism housings (CRDM nozzles) penetrate the head. The boric acid deposits resulted from primary coolant leaking from cracks in the nozzle attachment weld and from through-thickness cracks in the nozzle wall. A general overview of the inspection and repair process is presented and results of the metallurgical analysis are discussed in more detail. The analysis confirmed that primary water stress corrosion cracking (PWSCC) is the mechanism of failure of both the Alloy 182 weld filler material and the alloy 600 wrought base material. (authors)

  18. Virtual Field Trips.

    ERIC Educational Resources Information Center

    Walter, Virginia A.

    1997-01-01

    Virtual field trips can provide experiences beyond the reach of average K-12 students. Describes multimedia products for school use: Africa Trail, Dinosaur Hunter, Louvre Museum, Magic School Bus Explores the Rainforest, and Up to the Himalayas: Kingdoms in the Clouds and provides book and Internet connections for additional learning, highlighting…

  19. Administration Trip Books

    DTIC Science & Technology

    2007-11-02

    Plan. (h) Army Community of Excellence. (i) Child development services. k. The Assistant Secretary of the Army for Manpower and Reserve Affairs ( ASAM ...RA) will — (1) Provide information as requested when the information falls under the purview of the ASAM &RA. (2) Provide recurring trip book

  20. Science Activities for School Trips.

    ERIC Educational Resources Information Center

    Quint, Walter C.

    1980-01-01

    Describes ways in which physics-learning activity packets can be used by high school students participating in trips organized by other departments. Provides an example of physics activities incorporated into an airplane trip to Disney World. (CS)

  1. Computer Based Virtual Field Trips.

    ERIC Educational Resources Information Center

    Clark, Kenneth F.; Hosticka, Alice; Schriver, Martha; Bedell, Jackie

    This paper discusses computer based virtual field trips that use technologies commonly found in public schools in the United States. The discussion focuses on the advantages of both using and creating these field trips for an instructional situation. A virtual field trip to Cumberland Island National Seashore, St. Marys, Georgia is used as a point…

  2. Guilt Trips and Love Withdrawal: Does Mothers' Use of Psychological Control Predict Depressive Symptoms among African American Adolescents?

    ERIC Educational Resources Information Center

    Mandara, Jelani; Pikes, Crysta L.

    2008-01-01

    This study examined the effects of maternal psychological control on the depressive symptoms of 152 lower socioeconomic status African American adolescents. After controlling for the effects of other parenting practices, psychological control had a strong positive relationship with girls' depressive symptoms, but none for boys, even though the 2…

  3. 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.

  4. Rhodopsin kinase and arrestin binding control the decay of photoactivated rhodopsin and dark adaptation of mouse rods.

    PubMed

    Frederiksen, Rikard; Nymark, Soile; Kolesnikov, Alexander V; Berry, Justin D; Adler, Leopold; Koutalos, Yiannis; Kefalov, Vladimir J; Cornwall, M Carter

    2016-07-01

    Photoactivation of vertebrate rhodopsin converts it to the physiologically active Meta II (R*) state, which triggers the rod light response. Meta II is rapidly inactivated by the phosphorylation of C-terminal serine and threonine residues by G-protein receptor kinase (Grk1) and subsequent binding of arrestin 1 (Arr1). Meta II exists in equilibrium with the more stable inactive form of rhodopsin, Meta III. Dark adaptation of rods requires the complete thermal decay of Meta II/Meta III into opsin and all-trans retinal and the subsequent regeneration of rhodopsin with 11-cis retinal chromophore. In this study, we examine the regulation of Meta III decay by Grk1 and Arr1 in intact mouse rods and their effect on rod dark adaptation. We measure the rates of Meta III decay in isolated retinas of wild-type (WT), Grk1-deficient (Grk1(-/-)), Arr1-deficient (Arr1(-/-)), and Arr1-overexpressing (Arr1(ox)) mice. We find that in WT mouse rods, Meta III peaks ∼6 min after rhodopsin activation and decays with a time constant (τ) of 17 min. Meta III decay slows in Arr1(-/-) rods (τ of ∼27 min), whereas it accelerates in Arr1(ox) rods (τ of ∼8 min) and Grk1(-/-) rods (τ of ∼13 min). In all cases, regeneration of rhodopsin with exogenous 11-cis retinal is rate limited by the decay of Meta III. Notably, the kinetics of rod dark adaptation in vivo is also modulated by the levels of Arr1 and Grk1. We conclude that, in addition to their well-established roles in Meta II inactivation, Grk1 and Arr1 can modulate the kinetics of Meta III decay and rod dark adaptation in vivo.

  5. Rhodopsin kinase and arrestin binding control the decay of photoactivated rhodopsin and dark adaptation of mouse rods

    PubMed Central

    Nymark, Soile; Kolesnikov, Alexander V.; Berry, Justin D.; Adler, Leopold; Koutalos, Yiannis; Kefalov, Vladimir J.; Cornwall, M. Carter

    2016-01-01

    Photoactivation of vertebrate rhodopsin converts it to the physiologically active Meta II (R*) state, which triggers the rod light response. Meta II is rapidly inactivated by the phosphorylation of C-terminal serine and threonine residues by G-protein receptor kinase (Grk1) and subsequent binding of arrestin 1 (Arr1). Meta II exists in equilibrium with the more stable inactive form of rhodopsin, Meta III. Dark adaptation of rods requires the complete thermal decay of Meta II/Meta III into opsin and all-trans retinal and the subsequent regeneration of rhodopsin with 11-cis retinal chromophore. In this study, we examine the regulation of Meta III decay by Grk1 and Arr1 in intact mouse rods and their effect on rod dark adaptation. We measure the rates of Meta III decay in isolated retinas of wild-type (WT), Grk1-deficient (Grk1−/−), Arr1-deficient (Arr1−/−), and Arr1-overexpressing (Arr1ox) mice. We find that in WT mouse rods, Meta III peaks ∼6 min after rhodopsin activation and decays with a time constant (τ) of 17 min. Meta III decay slows in Arr1−/− rods (τ of ∼27 min), whereas it accelerates in Arr1ox rods (τ of ∼8 min) and Grk1−/− rods (τ of ∼13 min). In all cases, regeneration of rhodopsin with exogenous 11-cis retinal is rate limited by the decay of Meta III. Notably, the kinetics of rod dark adaptation in vivo is also modulated by the levels of Arr1 and Grk1. We conclude that, in addition to their well-established roles in Meta II inactivation, Grk1 and Arr1 can modulate the kinetics of Meta III decay and rod dark adaptation in vivo. PMID:27353443

  6. Driving following Kava Use and Road Traffic Injuries: A Population-Based Case-Control Study in Fiji (TRIP 14)

    PubMed Central

    Wainiqolo, Iris; Kafoa, Berlin; Kool, Bridget; Robinson, Elizabeth; Herman, Josephine; McCaig, Eddie; Ameratunga, Shanthi

    2016-01-01

    Objective To investigate the association between kava use and the risk of four-wheeled motor vehicle crashes in Fiji. Kava is a traditional beverage commonly consumed in many Pacific Island Countries. Herbal anxiolytics containing smaller doses of kava are more widely available. Methods Data for this population-based case-control study were collected from drivers of ‘case’ vehicles involved in serious injury-involved crashes (where at least one road user was killed or admitted to hospital for 12 hours or more) and ‘control’ vehicles representative of ‘driving time’ in the study base. Structured interviewer administered questionnaires collected self-reported participant data on demographic characteristics and a range of risk factors including kava use and potential confounders. Unconditional logistic regression models estimated odds ratios relating to the association between kava use and injury-involved crash risk. Findings Overall, 23% and 4% of drivers of case and control vehicles, respectively, reported consuming kava in the 12 hours prior to the crash or road survey. After controlling for assessed confounders, driving following kava use was associated with a four-fold increase in the odds of crash involvement (Odds ratio: 4.70; 95% CI: 1.90–11.63). The related population attributable risk was 18.37% (95% CI: 13.77–22.72). Acknowledging limited statistical power, we did not find a significant interaction in this association with concurrent alcohol use. Conclusion In this study conducted in a setting where recreational kava consumption is common, driving following the use of kava was associated with a significant excess of serious-injury involved road crashes. The precautionary principle would suggest road safety strategies should explicitly recommend avoiding driving following kava use, particularly in communities where recreational use is common. PMID:26930404

  7. 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.

  8. 49 CFR 236.531 - Trip arm; height and distance from rail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Trip arm; height and distance from rail. 236.531... Train Stop, Train Control and Cab Signal Systems Rules and Instructions; Roadway § 236.531 Trip arm; height and distance from rail. Trip arm of automatic train stop device when in the stop position shall...

  9. 49 CFR 236.531 - Trip arm; height and distance from rail.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Trip arm; height and distance from rail. 236.531... Train Stop, Train Control and Cab Signal Systems Rules and Instructions; Roadway § 236.531 Trip arm; height and distance from rail. Trip arm of automatic train stop device when in the stop position shall...

  10. 49 CFR 236.531 - Trip arm; height and distance from rail.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Trip arm; height and distance from rail. 236.531... Train Stop, Train Control and Cab Signal Systems Rules and Instructions; Roadway § 236.531 Trip arm; height and distance from rail. Trip arm of automatic train stop device when in the stop position shall...

  11. 49 CFR 236.531 - Trip arm; height and distance from rail.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Trip arm; height and distance from rail. 236.531... Train Stop, Train Control and Cab Signal Systems Rules and Instructions; Roadway § 236.531 Trip arm; height and distance from rail. Trip arm of automatic train stop device when in the stop position shall...

  12. 49 CFR 236.531 - Trip arm; height and distance from rail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Trip arm; height and distance from rail. 236.531... Train Stop, Train Control and Cab Signal Systems Rules and Instructions; Roadway § 236.531 Trip arm; height and distance from rail. Trip arm of automatic train stop device when in the stop position shall...

  13. The inner rod protein controls substrate switching and needle length in a Salmonella type III secretion system.

    PubMed

    Lefebre, Matthew D; Galán, Jorge E

    2014-01-14

    Type III secretion machines are essential for the biology of many bacteria that are pathogenic or symbiotic for animals, plants, or insects. They exert their function by delivering bacterial effector proteins into target eukaryotic cells. The core component of these machines is the needle complex, a multiprotein structure that spans the bacterial envelope and serves as a conduit for proteins that transit this secretion pathway. The needle complex is composed of a multiring base embedded in the bacterial envelope and a filament-like structure, the needle, that projects from the bacterial surface and is linked to the base by the inner rod. Assembly of the needle complex proceeds in a step-wise fashion that is initiated by the assembly of the base and is followed by the export of the building subunits for the needle and inner rod substructures. Once assembled, the needle complex reprograms its specificity and becomes competent for the secretion of effector proteins. Here through genetic, biochemical, and electron microscopy analyses of the Salmonella inner rod protein subunit PrgJ we present evidence that the assembly of the inner rod dictates the timing of substrate switching and needle length. Furthermore, the identification of mutations in PrgJ that specifically alter the hierarchy of protein secretion provides additional support for a complex role of the inner rod substructure in type III secretion.

  14. 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.

  15. The TRAF-interacting protein (TRIP) is a regulator of keratinocyte proliferation.

    PubMed

    Almeida, Stéphanie; Ryser, Stephan; Obarzanek-Fojt, Magdalena; Hohl, Daniel; Huber, Marcel

    2011-02-01

    The TRAF-interacting protein (TRIP/TRAIP) is a RING-type E3 ubiquitin ligase inhibiting tumor necrosis factor-α (TNF-α)-mediated NF-κB activation. TRIP ablation results in early embryonic lethality in mice. To investigate TRIP function in epidermis, we examined its expression and the effect of TRIP knockdown (KD) in keratinocytes. TRIP mRNA expression was strongly downregulated in primary human keratinocytes undergoing differentiation triggered by high cell density or high calcium. Short-term phorbol-12-myristate-13-acetate (TPA) treatment or inhibition of phosphatidylinositol-3 kinase signaling in proliferative keratinocytes suppressed TRIP transcription. Inhibition by TPA was protein kinase C dependent. Keratinocytes undergoing KD of TRIP expression by lentiviral short-hairpin RNA (shRNA; T4 and T5) had strongly reduced proliferation rates compared with control shRNA. Cell cycle analysis demonstrated that TRIP-KD caused growth arrest in the G1/S phase. Keratinocytes with TRIP-KD resembled differentiated cells consistent with the augmented expression of differentiation markers keratin 1 and filaggrin. Luciferase-based reporter assays showed no increase in NF-κB activity in TRIP-KD keratinocytes, indicating that NF-κB activity in keratinocytes is not regulated by TRIP. TRIP expression was increased by ∼2-fold in basal cell carcinomas compared with normal skin. These results underline the important role of TRIP in the regulation of cell cycle progression and the tight linkage of its expression to keratinocyte proliferation.

  16. Elementary school children's science learning from school field trips

    NASA Astrophysics Data System (ADS)

    Glick, Marilyn Petty

    This research examines the impact of classroom anchoring activities on elementary school students' science learning from a school field trip. Although there is prior research demonstrating that students can learn science from school field trips, most of this research is descriptive in nature and does not examine the conditions that enhance or facilitate such learning. The current study draws upon research in psychology and education to create an intervention that is designed to enhance what students learn from school science field trips. The intervention comprises of a set of "anchoring" activities that include: (1) Orientation to context, (2) Discussion to activate prior knowledge and generate questions, (3) Use of field notebooks during the field trip to record observations and answer questions generated prior to field trip, (4) Post-visit discussion of what was learned. The effects of the intervention are examined by comparing two groups of students: an intervention group which receives anchoring classroom activities related to their field trip and an equivalent control group which visits the same field trip site for the same duration but does not receive any anchoring classroom activities. Learning of target concepts in both groups was compared using objective pre and posttests. Additionally, a subset of students in each group were interviewed to obtain more detailed descriptive data on what children learned through their field trip.

  17. Chemical State Mapping of Degraded B4C Control Rod Investigated with Soft X-ray Emission Spectrometer in Electron Probe Micro-analysis.

    PubMed

    Kasada, R; Ha, Y; Higuchi, T; Sakamoto, K

    2016-05-10

    B4C is widely used as control rods in light water reactors, such as the Fukushima Daiichi nuclear power plant, because it shows excellent neutron absorption and has a high melting point. However, B4C can melt at lower temperatures owing to eutectic interactions with stainless steel and can even evaporate by reacting with high-temperature steam under severe accident conditions. To reduce the risk of recriticality, a precise understanding of the location and chemical state of B in the melt core is necessary. Here we show that a novel soft X-ray emission spectrometer in electron probe microanalysis can help to obtain a chemical state map of B in a modeled control rod after a high-temperature steam oxidation test.

  18. Chemical State Mapping of Degraded B4C Control Rod Investigated with Soft X-ray Emission Spectrometer in Electron Probe Micro-analysis

    NASA Astrophysics Data System (ADS)

    Kasada, R.; Ha, Y.; Higuchi, T.; Sakamoto, K.

    2016-05-01

    B4C is widely used as control rods in light water reactors, such as the Fukushima Daiichi nuclear power plant, because it shows excellent neutron absorption and has a high melting point. However, B4C can melt at lower temperatures owing to eutectic interactions with stainless steel and can even evaporate by reacting with high-temperature steam under severe accident conditions. To reduce the risk of recriticality, a precise understanding of the location and chemical state of B in the melt core is necessary. Here we show that a novel soft X-ray emission spectrometer in electron probe microanalysis can help to obtain a chemical state map of B in a modeled control rod after a high-temperature steam oxidation test.

  19. Field Trips Within Easy Reach.

    ERIC Educational Resources Information Center

    Fitzsimmons, Charles P.

    1983-01-01

    Provides suggestions for conducting field trips at the local school site. Points of interest might include building materials, evidence of chemical/physical weathering, variations in soil type, changes in elevation on school ground, and others. Three simple field trips are described. (JN)

  20. 8th Grade Canadian Trip.

    ERIC Educational Resources Information Center

    Jelinek, Gilbert; Schoenike, Paul

    Ideas are offered for helping eighth-grade students incorporate an at-home field trip to Canada into a social studies unit. The teachers who developed the unit state that students can complete the 21-day imaginary trip in five hours of classroom time when appropriate materials are available and the classroom environment is conducive to working on…

  1. 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.

  2. Squishy Physics Field Trips

    NASA Astrophysics Data System (ADS)

    Weeks, Eric R.; Cianci, Gianguido; Habdas, Piotr

    2008-03-01

    Our laboratory studies soft condensed matter, which means we investigate squishy materials such as foams, emulsions, and colloidal suspensions. These materials include common things such as peanut butter, toothpaste, mayonnaise, shampoo, and shaving cream. We have conducted several field trips for grade school students, where they come to our laboratory and play with squishy materials. They do both hands-on table-top projects and also look at samples with a microscope. We have also developed some of these activities into labs appropriate for first-year college students. Our first goal for these activities is to show students that science is fun, and the second goal is to get them intrigued by the idea that there are more phases than just solids, liquids, and gases.

  3. Apollo 14 Road Trip

    NASA Astrophysics Data System (ADS)

    Valleli, P.

    2012-06-01

    (Abstract only) In January-February 1971, five astronomy enthusiasts, Dennis Milon, Alan Rowher, Sal LaRiccia, Mike Mattei, and Paul Valleli, drove from New Haven, Connecticut, to the Kennedy Space Center at Cape Canaveral, Florida. They joined with ALPO Jupiter Recorder Julius Benton in Atlanta. After several stops along the way, the six arrived at the Apollo 14 launch site to observe pre-launch activity, met NASA personnel, and toured various facilities. On launch day, thanks to press passes provided by Dennis Milon who was there as the official photojournalist for Sky & Telescope, they met the Apollo crew and witnessed the launch. On the return trip, they made time to meet Mike Mattei's new girlfriend, Janet Akyü;z, who was working on her Master's at Leander-McCormick Observatory in Charlottesville, Virginia. Janet gave the six men a tour of the observatory, including the the 26-inch Clark Telescope.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. A Destructive Validation of NDE Responses of Service-Induced PWSCC Found in North Anna 2 Control Rod Drive Nozzle 31

    SciTech Connect

    Cumblidge, Stephen E.; Doctor, Steven R.; Schuster, George J.; Harris, Robert V.; Crawford, Susan L.; Seffens, Rob J.; Toloczko, Mychailo B.; Bruemmer, Stephen M.; Moyer, C.

    2009-07-01

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies.

  10. Using a Field Trip Inventory to Determine If Listening to Elementary School Students' Conversations, While on a Zoo Field Trip, Enhances Preservice Teachers' Abilities to Plan Zoo Field Trips

    NASA Astrophysics Data System (ADS)

    Patrick, Patricia; Mathews, Cathy; Tunnicliffe, Sue Dale

    2013-10-01

    This study investigated whether listening to spontaneous conversations of elementary students and their teachers/chaperones, while they were visiting a zoo, affected preservice elementary teachers' conceptions about planning a field trip to the zoo. One hundred five preservice elementary teachers designed field trips prior to and after listening to students' conversations during a field trip to the zoo. In order to analyze the preservice teachers' field trip designs, we conducted a review of the literature on field trips to develop the field trip inventory (FTI). The FTI focussed on three major components of field trips: cognitive, procedural, and social. Cognitive components were subdivided into pre-visit, during-visit, and post-visit activities and problem-solving. Procedural components included information about the informal science education facility (the zoo) and the zoo staff and included advanced organizers. Social components on student groups, fun, control during the zoo visit, and control of student learning. The results of the investigation showed that (a) the dominant topic in conversations among elementary school groups at the zoo was management, (b) procedural components were mentioned least often, (c) preservice teachers described during-visit activities more often than any other characteristic central to field trip design, (d) seven of the nine characteristics listed in the FTI were noted more frequently in the preservice teachers' field trip designs after they listened to students' conversations at the zoo, and (e) preservice teachers thought that students were not learning and that planning was important.

  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. Investigation of combined free and forced convection in a 2 x 6 rod bundle during controlled flow transients

    SciTech Connect

    Bates, J.M.; Khan, E.U.

    1980-10-01

    An experimental study was performed to obtain local fluid velocity and temperature measurements in the mixed (combined free and forced) convection regime for specific flow coastdown transients. A brief investigation of steady-state flows for the purely free-convection regime was also completed. The study was performed using an electrically heated 2 x 6 rod bundle contained in a flow housing. In addition a transient data base was obtained for evaluating the COBRA-WC thermal-hydraulic computer program (a modified version of the COBRA-IV code).

  13. Thermal management, beam control, and packaging designs for high power diode laser arrays and pump cavity designs for diode laser array pumped rod shaped lasers

    NASA Astrophysics Data System (ADS)

    Chung, Te-Yuan

    Several novel techniques for controlling, managing and utilizing high power diode lasers are described. Low pressure water spray cooling for a high heat flux system is developed and proven to be an ideal cooling method for high power diode laser arrays. In order to enable better thermal and optical performance of diode laser arrays, a new and simple optical element, the beam control prism, is invented. It provides the ability to accomplish beam shaping and beam tilting at the same time. Several low thermal resistance diode packaging designs using beam control prisms are proposed, studied and produced. Two pump cavity designs using a diode laser array to uniformly pump rod shape gain media are also investigated.

  14. Microstructural engineering applied to the controlled cooling of steel wire rod: Part II. Microstructural evolution and mechanical properties correlations

    NASA Astrophysics Data System (ADS)

    Campbell, P. C.; Hawbolt, E. B.; Brimacombe, J. K.

    1991-11-01

    In the second part of this paper, the microstructural evolution and mechanical properties of plain-carbon steel rods which have been subjected to known cooling conditions are described. Specifically, the isothermal phase transformation kinetics for the decomposition of austenite into ferrite and pearlite have been determined with a diametral dilatometer and characterized in terms of empirical coefficients in the Avrami equation. The continuous cooling transformation (CCT) start time, fraction ferrite, ferrite grain diameter, and pearlite interlamellar spacing have been quantified and correlated with steel composition and cooling rate. Tensile tests have been conducted to obtain yield strength (YS) and ultimate tensile strength (UTS), which, with literature data, have been related to the microstructure and composition of the steels. These correlations, which apply to both hypoeutectoid and eutectoid steels, have been incorporated in a mathematical model of the Stelmor process, to be described in Part III of this article.[441

  15. Effect of rod gap spacing on a suction panel for laminar flow and noise control in supersonic wind tunnels. M.S. Thesis - Old Dominion Univ.

    NASA Technical Reports Server (NTRS)

    Harvey, W. D.

    1975-01-01

    Results are presented of a coordinated experimental and theoretical study of a sound shield concept which aims to provide a means of noise reduction in the test section of supersonic wind tunnels at high Reynolds numbers. The model used consists of a planar array of circular rods aligned with the flow, with adjustable gaps between them for boundary layer removal by suction, i.e., laminar flow control. One of the basic requirements of the present sound shield concept is to achieve sonic cross flow through the gaps in order to prevent lee-side flow disturbances from penetrating back into the shielded region. Tests were conducted at Mach 6 over a local unit Reynolds number range from about 1.2 x 10 to the 6th power to 13.5 x 10 to the 6th power per foot. Measurements of heat transfer, static pressure, and sound levels were made to establish the transition characteristics of the boundary layer on the rod array and the sound shielding effectiveness.

  16. Katimavik Out-Trip Protocol.

    ERIC Educational Resources Information Center

    OPCAN, Montreal (Quebec).

    A supplement to the active leisure learning student manual for Katimavik (the 9-month volunteer community service and experiential learning program for 17-21 year old Canadians) provides in greater detail the procedure for preparing and implementing the Outdoor Wilderness Trip. Sections presented are definition of terms, national training,…

  17. Learning from a Bike Trip

    ERIC Educational Resources Information Center

    Koren, Mike

    2009-01-01

    In this article, the author describes a bike trip which marks the culmination of a unit reviewing map-reading capabilities. In seventh grade, students develop various map skills, including cardinal and intermediate directions, how to measure distance on a map using a scale of miles, how to interpret the legend of a map, and how to locate places…

  18. 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.

  19. 30 CFR 57.14162 - Trip lights.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Trip lights. 57.14162 Section 57.14162 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Devices and Maintenance Requirements § 57.14162 Trip lights. On underground rail haulage, trip...

  20. 30 CFR 57.14162 - Trip lights.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Trip lights. 57.14162 Section 57.14162 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Devices and Maintenance Requirements § 57.14162 Trip lights. On underground rail haulage, trip...

  1. 30 CFR 57.14162 - Trip lights.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Trip lights. 57.14162 Section 57.14162 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Devices and Maintenance Requirements § 57.14162 Trip lights. On underground rail haulage, trip...

  2. 30 CFR 57.14162 - Trip lights.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Trip lights. 57.14162 Section 57.14162 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Devices and Maintenance Requirements § 57.14162 Trip lights. On underground rail haulage, trip...

  3. One-trip drum operating instruction

    SciTech Connect

    Ruff, D.T.

    1994-10-01

    The one trip system is a bagless transfer system for egress of waste from gloveboxes into 55 gallon one-trip drums. The contents of this document give an overview of the assembly, loading, and handling of the one-trip drum for use in the WRAP-1 plant.

  4. 30 CFR 57.14162 - Trip lights.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trip lights. 57.14162 Section 57.14162 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Devices and Maintenance Requirements § 57.14162 Trip lights. On underground rail haulage, trip...

  5. Tourism, Field Trips and Geographic Education.

    ERIC Educational Resources Information Center

    Dilsaver, Lary M.

    In university level geography education, both a market and a need exist for "learning trips" combining the elements of a field trip with those of a commercial tour. Planning such trips involves four steps. The first of these is to establish the conditions of the tour, including identification of the topical focus, specific destinations and sites…

  6. International Virtual Field Trips: A New Direction?

    ERIC Educational Resources Information Center

    Stainfield, John; Fisher, Peter; Ford, Bob; Solem, Michael

    2000-01-01

    Traces the evolution of virtual field trips and discusses both the advantages and disadvantages of the virtual field trip. Explores three approaches to improving the interactivity of virtual field trips (interactive field exercises, generic software, and student-centered Web sites). Includes references. (CMK)

  7. Real Students and Virtual Field Trips

    NASA Astrophysics Data System (ADS)

    de Paor, D. G.; Whitmeyer, S. J.; Bailey, J. E.; Schott, R. C.; Treves, R.; Scientific Team Of Www. Digitalplanet. Org

    2010-12-01

    Field trips have always been one of the major attractions of geoscience education, distinguishing courses in geology, geography, oceanography, etc., from laboratory-bound sciences such as nuclear physics or biochemistry. However, traditional field trips have been limited to regions with educationally useful exposures and to student populations with the necessary free time and financial resources. Two-year or commuter colleges serving worker-students cannot realistically insist on completion of field assignments and even well-endowed universities cannot take students to more than a handful of the best available field localities. Many instructors have attempted to bring the field into the classroom with the aid of technology. So-called Virtual Field Trips (VFTs) cannot replace the real experience for those that experience it but they are much better than nothing at all. We have been working to create transformative improvements in VFTs using four concepts: (i) self-drive virtual vehicles that students use to navigate the virtual globe under their own control; (ii) GigaPan outcrops that reveal successively more details views of key locations; (iii) virtual specimens scanned from real rocks, minerals, and fossils; and (iv) embedded assessment via logging of student actions. Students are represented by avatars of their own choosing and travel either together in a virtual field vehicle, or separately. When they approach virtual outcrops, virtual specimens become collectable and can be examined using Javascript controls that change magnification and orientation. These instructional resources are being made available via a new server under the domain name www.DigitalPlanet.org. The server will log student progress and provide immediate feedback. We aim to disseminate these resources widely and welcome feedback from instructors and students.

  8. 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.

  9. Venus round trip using solar sail

    NASA Astrophysics Data System (ADS)

    Zhu, KaiJian; Zhang, RongZhi; Xu, Dong; Wang, JiaSong; Li, ShaoMin

    2012-08-01

    Trajectory optimization and simulation is performed for Venus round trip (VeRT) mission using solar sail propulsion. Solar gravity is included but atmospheric drag and shadowing effects are neglected in the planet-centered escape and capture stages. The spacecraft starts from the Geostationary orbit (GEO) at a predetermined time to prepare a good initial condition for the Earth-Venus transfer, although the launch window is not an issue for spacecraft with solar sails. The Earth-Venus phase and the return trip are divided into three segments. Two methods are adopted to maintain the mission trajectory for the VeRT mission and then compared through a numerical simulation. According to the first approach, Planet-centered and heliocentric maneuvers are modeled using a set of blended analytical control laws instead of the optimal control techniques. The second procedure is the Direct Attitude Angle Optimization in which the attitude angles of the solar sail are adopted as the optimization variables during the heliocentric transfer. Although neither of the two methods guarantees a globally optimal trajectory, they are more efficient and will produce a near-optimal solution if employed properly. The second method has produced a better result for the minimum-time transfer of the VeRT mission demonstrating the effectiveness of the methods in the preliminary design of the complex optimal interplanetary orbit transfers.

  10. Benzil-tethered precipitons for controlling solubility: a round-trip energy-transfer mechanism in the isomerization of extended stilbene analogues.

    PubMed

    Ams, Mark R; Wilcox, Craig S

    2007-04-04

    We are investigating photoresponsive molecules called "precipitons" that undergo a solubility change co-incident with isomerization. Isomerization can be induced by light or by catalytic reagents. Previous work demonstrated that covalent attachment of a metal complex, Ru(II)(bpy)3, greatly accelerates photoisomerization and influences the photostationary state. In this paper, we describe precipitons (1,2-biphenylethenes; analogous to stilbenes) that are activated by a covalently attached organic sensitizer (benzil). We find that isomerization of these stilbene analogues is little effected by the presence of benzil in solution but that the intramolecular benzil effect is to increase the rate of isomerization and to significantly change the photostationary state. What is most interesting about these observations is that the precipiton is the primary chromophore in this bichromophoric system (precipiton absorbance is many times greater than benzil absorbance in the 300-400 nm range), yet the neighboring benzil has a significant effect on the rate and the photostationary state. The effect of unattached benzil on the rate was small, about a 24% increase in rate as compared with 4-6-fold changes for an attached benzil. We speculate that the isomerization process occurs by a "round-trip" energy-transfer mechanism. Initial excitation of the precipiton chromophore initiates a sequence that includes (1) formation of the precipiton singlet state, (2) singlet excitation transfer from the precipiton unit to the benzil, (3) benzil-centered intersystem crossing to the localized benzil triplet state, (4) triplet energy transfer from the benzil moiety back to the precipiton, and (5) isomerization.

  11. The Effect of Planetarium Trip on Pre-Service Science Teachers' Metaphorical Perceptions about Planetariums

    ERIC Educational Resources Information Center

    Bozdogan, Aykut Emre

    2016-01-01

    The study aimed at examining the effect of the planetarium trip on metaphors developed by the pre-service science teachers about the concept of planetarium. Within this context of the study, a trip was organized to Ondokuz Mayis University (OMU) Planetarium. Pretest-posttest control group design, one of the experimental designs, was used in the…

  12. Validation of updated neutronic calculation models proposed for Atucha-II PHWR. Part I: Benchmark comparisons of WIMS-D5 and DRAGON cell and control rod parameters with MCNP5

    SciTech Connect

    Mollerach, R.; Leszczynski, F.; Fink, J.

    2006-07-01

    In 2005 the Argentine Government took the decision to complete the construction of the Atucha-II nuclear power plant, which has been progressing slowly during the last ten years. Atucha-II is a 745 MWe nuclear station moderated and cooled with heavy water, of German (Siemens) design located in Argentina. It has a pressure-vessel design with 451 vertical coolant channels, and the fuel assemblies (FA) are clusters of 37 natural UO{sub 2} rods with an active length of 530 cm. For the reactor physics area, a revision and update calculation methods and models (cell, supercell and reactor) was recently carried out covering cell, supercell (control rod) and core calculations. As a validation of the new models some benchmark comparisons were done with Monte Carlo calculations with MCNP5. This paper presents comparisons of cell and supercell benchmark problems based on a slightly idealized model of the Atucha-I core obtained with the WIMS-D5 and DRAGON codes with MCNP5 results. The Atucha-I core was selected because it is smaller, similar from a neutronic point of view, and more symmetric than Atucha-II Cell parameters compared include cell k-infinity, relative power levels of the different rings of fuel rods, and some two-group macroscopic cross sections. Supercell comparisons include supercell k-infinity changes due to the control rods (tubes) of steel and hafnium. (authors)

  13. Field Experiences for Young Children: Planning and Implementing Field Trips, Classroom Visitors and Collecting Trips.

    ERIC Educational Resources Information Center

    Schneider, Anne; Warner, Jane

    This document provides guidelines and suggestions for taking preschool children on field trips. Rationale for field trips, safety considerations, planning, preparation through classroom activities, parent involvement and keeping a field experience reference file are among the topics discussed. Examples of trips to a supermarket and to hear a high…

  14. 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.

  15. Ultrasonic Phased Array Assessment of the Interference Fit and Leak Path of the North Anna Unit 2 Control Rod Drive Mechanism Nozzle 63 with Destructive Validation

    SciTech Connect

    Crawford, Susan L.; Cinson, Anthony D.; MacFarlan, Paul J.; Hanson, Brady D.; Mathews, Royce

    2012-08-01

    The objective of this investigation was to evaluate the efficacy of ultrasonic testing (UT) for primary water leak path assessments of reactor pressure vessel (RPV) upper head penetrations. Operating reactors have experienced leakage when stress corrosion cracking of nickel-based alloy penetrations allowed primary water into the annulus of the interference fit between the penetration and the low-alloy steel RPV head. In this investigation, UT leak path data were acquired for an Alloy 600 control rod drive mechanism nozzle penetration, referred to as Nozzle 63, which was removed from the North Anna Unit 2 reactor when the RPV head was replaced in 2002. In-service inspection prior to the head replacement indicated that Nozzle 63 had a probable leakage path through the interference fit region. Nozzle 63 was examined using a phased-array UT probe with a 5.0-MHz, eight-element annular array. Immersion data were acquired from the nozzle inner diameter surface. The UT data were interpreted by comparing to responses measured on a mockup penetration with known features. Following acquisition of the UT data, Nozzle 63 was destructively examined to determine if the features identified in the UT examination, including leakage paths and crystalline boric acid deposits, could be visually confirmed. Additional measurements of boric acid deposit thickness and low-alloy steel wastage were made to assess how these factors affect the UT response. The implications of these findings for interpreting UT leak path data are described.

  16. Controlled synthesis of CeO2 microstructures from 1D rod-like to 3D lotus-like and their morphology-dependent properties

    NASA Astrophysics Data System (ADS)

    Gong, Jinfeng; Meng, Fanming; Fan, Zhenghua; Li, Huijie

    2016-10-01

    Monodisperse 3D lotus-like CeO2 microstructures have been successfully synthesized via controlling the morphology of CeCO3OH precursors under hydrothermal condition as well as subsequent calcination. The reaction time was systematically investigated. XRD, FT-IR, SEM, TEM, XPS, Raman scattering and Photoluminescence (PL) spectra were employed to characterize the samples. The lotus-like CeO2 hierarchical structures with an average of 4-6 μm are composed of many nanoplates of 100-200 nm in thickness as the petals stacking together to form open flowers and have a fluorite cubic structure. Based on the time-dependent morphology evolution evidences, a nucleation-dissolution-recrystallization mechanism has been proposed to explain the transformation from rod-like structures to lotus-like CeO2 hierarchical structures with the increase of reaction time. It is found that there are Ce3+ ions and oxygen vacancies in surface of samples. The magnetic and photoluminescence measurements indicated that all CeO2 samples exhibit excellent ferromagnetism and optical properties at room temperature, and while increasing the reaction time, the ferromagnetism and optical properties increase more, which can be reasonably explained for the influences of the different morphology of the particles and the concentration of oxygen vacancies and Ce3+ ions. [Figure not available: see fulltext.

  17. Study on Fracture Behavior of 2D-C/C Composite for Application to Control Rod of Very High Temperature Reactor

    NASA Astrophysics Data System (ADS)

    Sumita, J.; Fujita, I.; Shibata, T.; Makita, T.; Takagi, T.; Kunimoto, E.; Sawa, K.; Kim, W.; Park, J.

    2011-10-01

    For a control rod element of the Very High Temperature Reactor, a carbon fiber reinforced carbon matrix composite (C/C composite) is one of the major candidate materials for its high strength and thermal stability. In this study, in order to establish the data base of the 2D-C/C composite, the fracture data was obtained by simulating the crack expected to be generated under the VHTR condition and the oxidation effect on the fracture behavior was evaluated. Moreover, the fracture mechanism of the C/C composite was investigated through scanning electron microscope observation. This study showed that the oxidized matrix caused reduction of the fracture toughness and the reduction ratio was dependent on the density of matrix and a number cracks. With increasing the oxidation, the fracture toughness is mainly dependent on the fiber characteristics. Furthermore, the crack grows along the boundary between fiber bundles without breaking the fiber. The cracks which were initiated at the interface between the matrix and the fiber were gathered into the voids in the boundary between fiber bundles, and, then, the cracks grew up in the matrix.

  18. 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.

  19. Peach Bottom BWR Turbine Trip Benchmark Analyses with RETRAN-3D and CORETRAN

    SciTech Connect

    Barten, W.; Ferroukhi, H.; Coddington, P.

    2004-10-15

    This paper presents results from Paul Scherrer Institut (PSI) on the three phases of the Peach Bottom Boiling Water Reactor Turbine Trip Benchmark. The first part of the paper presents the PSI analysis using RETRAN-3D of Phase 1, where the system pressure is predicted based on a predefined core power distribution. These calculations elucidate the importance of accurate modeling of the steam separator region and of nonequilibrium effects. In the second part, the CORETRAN results of Phase 2 are summarized and the core 3-D response to the pressurization transient prior to SCRAM is discussed. The CORETRAN results show a slight axial flux redistribution toward the top of the core, while radially a flux redistribution is observed toward core regions with assemblies that are initially moderately voided and where the axial power shape is increasingly top-peaked. The impact of the control rod configuration as well as the assembly coolant inventory dynamics on the 3-D flux redistribution is also discussed. The third part presents results of the Phase 3 calculation using RETRAN-3D, which is a culmination of the analytical work of Phases 1 and 2.

  20. The development of a thermal hydraulic feedback mechanism with a quasi-fixed point iteration scheme for control rod position modeling for the TRIGSIMS-TH application

    NASA Astrophysics Data System (ADS)

    Karriem, Veronica V.

    Nuclear reactor design incorporates the study and application of nuclear physics, nuclear thermal hydraulic and nuclear safety. Theoretical models and numerical methods implemented in computer programs are utilized to analyze and design nuclear reactors. The focus of this PhD study's is the development of an advanced high-fidelity multi-physics code system to perform reactor core analysis for design and safety evaluations of research TRIGA-type reactors. The fuel management and design code system TRIGSIMS was further developed to fulfill the function of a reactor design and analysis code system for the Pennsylvania State Breazeale Reactor (PSBR). TRIGSIMS, which is currently in use at the PSBR, is a fuel management tool, which incorporates the depletion code ORIGEN-S (part of SCALE system) and the Monte Carlo neutronics solver MCNP. The diffusion theory code ADMARC-H is used within TRIGSIMS to accelerate the MCNP calculations. It manages the data and fuel isotopic content and stores it for future burnup calculations. The contribution of this work is the development of an improved version of TRIGSIMS, named TRIGSIMS-TH. TRIGSIMS-TH incorporates a thermal hydraulic module based on the advanced sub-channel code COBRA-TF (CTF). CTF provides the temperature feedback needed in the multi-physics calculations as well as the thermal hydraulics modeling capability of the reactor core. The temperature feedback model is using the CTF-provided local moderator and fuel temperatures for the cross-section modeling for ADMARC-H and MCNP calculations. To perform efficient critical control rod calculations, a methodology for applying a control rod position was implemented in TRIGSIMS-TH, making this code system a modeling and design tool for future core loadings. The new TRIGSIMS-TH is a computer program that interlinks various other functional reactor analysis tools. It consists of the MCNP5, ADMARC-H, ORIGEN-S, and CTF. CTF was coupled with both MCNP and ADMARC-H to provide the

  1. Differential Phosphorylation Provides a Switch to Control How α-Arrestin Rod1 Down-regulates Mating Pheromone Response in Saccharomyces cerevisiae

    PubMed Central

    Alvaro, Christopher G.; Aindow, Ann; Thorner, Jeremy

    2016-01-01

    G-protein-coupled receptors (GPCRs) are integral membrane proteins that initiate stimulus-dependent activation of cognate heterotrimeric G-proteins, triggering ensuing downstream cellular responses. Tight regulation of GPCR-evoked pathways is required because prolonged stimulation can be detrimental to an organism. Ste2, a GPCR in Saccharomyces cerevisiae that mediates response of MATa haploids to the peptide mating pheromone α-factor, is down-regulated by both constitutive and agonist-induced endocytosis. Efficient agonist-stimulated internalization of Ste2 requires its association with an adaptor protein, the α-arrestin Rod1/Art4, which recruits the HECT-domain ubiquitin ligase Rsp5, allowing for ubiquitinylation of the C-terminal tail of the receptor and its engagement by the clathrin-dependent endocytic machinery. We previously showed that dephosphorylation of Rod1 by calcineurin (phosphoprotein phosphatase 2B) is required for optimal Rod1 function in Ste2 down-regulation. We show here that negative regulation of Rod1 by phosphorylation is mediated by two distinct stress-activated protein kinases, Snf1/AMPK and Ypk1/SGK1, and demonstrate both in vitro and in vivo that this phospho-regulation impedes the ability of Rod1 to promote mating pathway desensitization. These studies also revealed that, in the absence of its phosphorylation, Rod1 can promote adaptation independently of Rsp5-mediated receptor ubiquitinylation, consistent with recent evidence that α-arrestins can contribute to cargo recognition by both clathrin-dependent and clathrin-independent mechanisms. However, in cells lacking a component (formin Bni1) required for clathrin-independent entry, Rod1 derivatives that are largely unphosphorylated and unable to associate with Rsp5 still promote efficient adaptation, indicating a third mechanism by which this α-arrestin promotes desensitization of the pheromone-response pathway. PMID:26920760

  2. Differential Phosphorylation Provides a Switch to Control How α-Arrestin Rod1 Down-regulates Mating Pheromone Response in Saccharomyces cerevisiae.

    PubMed

    Alvaro, Christopher G; Aindow, Ann; Thorner, Jeremy

    2016-05-01

    G-protein-coupled receptors (GPCRs) are integral membrane proteins that initiate stimulus-dependent activation of cognate heterotrimeric G-proteins, triggering ensuing downstream cellular responses. Tight regulation of GPCR-evoked pathways is required because prolonged stimulation can be detrimental to an organism. Ste2, a GPCR in Saccharomyces cerevisiae that mediates response of MATa haploids to the peptide mating pheromone α-factor, is down-regulated by both constitutive and agonist-induced endocytosis. Efficient agonist-stimulated internalization of Ste2 requires its association with an adaptor protein, the α-arrestin Rod1/Art4, which recruits the HECT-domain ubiquitin ligase Rsp5, allowing for ubiquitinylation of the C-terminal tail of the receptor and its engagement by the clathrin-dependent endocytic machinery. We previously showed that dephosphorylation of Rod1 by calcineurin (phosphoprotein phosphatase 2B) is required for optimal Rod1 function in Ste2 down-regulation. We show here that negative regulation of Rod1 by phosphorylation is mediated by two distinct stress-activated protein kinases, Snf1/AMPK and Ypk1/SGK1, and demonstrate both in vitro and in vivo that this phospho-regulation impedes the ability of Rod1 to promote mating pathway desensitization. These studies also revealed that, in the absence of its phosphorylation, Rod1 can promote adaptation independently of Rsp5-mediated receptor ubiquitinylation, consistent with recent evidence that α-arrestins can contribute to cargo recognition by both clathrin-dependent and clathrin-independent mechanisms. However, in cells lacking a component (formin Bni1) required for clathrin-independent entry, Rod1 derivatives that are largely unphosphorylated and unable to associate with Rsp5 still promote efficient adaptation, indicating a third mechanism by which this α-arrestin promotes desensitization of the pheromone-response pathway.

  3. What? A Field Trip on the Playground?

    ERIC Educational Resources Information Center

    Garbutt, Barb

    1983-01-01

    THE FOLLOWING IS THE FULL TEXT OF THIS DOCUMENT: In this day and age of budget problems, school districts are cutting back on many programs, one of which is field trips. Why worry? There must be dozens of trips that can be made on the playground of your school. Let's look into activities that can be accomplished there. SOIL STUDIES: Have you ever…

  4. The Case of the Field Trip Disaster

    ERIC Educational Resources Information Center

    Collins, Loucrecia; Redcross, Joseph

    2005-01-01

    For decades, the instructional field trip has been viewed as a strategy to enhance students' learning experiences. Yet what happens when an award-winning teacher is accused of choking a student while on a field trip? Tempers flare among community members, parents contact the police, and the principal is assigned the daunting task of investigating…

  5. Using Vessel Monitoring System Data to Identify and Characterize Trips Made by Fishing Vessels in the United States North Pacific

    PubMed Central

    Haynie, Alan C.

    2016-01-01

    Time spent fishing is the effort metric often studied in fisheries but it may under-represent the effort actually expended by fishers. Entire fishing trips, from the time vessels leave port until they return, may prove more useful for examining trends in fleet dynamics, fisher behavior, and fishing costs. However, such trip information is often difficult to resolve. We identified ~30,000 trips made by vessels that targeted walleye pollock (Gadus chalcogrammus) in the Eastern Bering Sea from 2008–2014 by using vessel monitoring system (VMS) and landings data. We compared estimated trip durations to observer data, which were available for approximately half of trips. Total days at sea were estimated with < 1.5% error and 96.4% of trip durations were either estimated with < 5% error or they were within expected measurement error. With 99% accuracy, we classified trips as fishing for pollock, for another target species, or not fishing. This accuracy lends strong support to the use of our method with unobserved trips across North Pacific fisheries. With individual trips resolved, we examined potential errors in datasets which are often viewed as “the truth.” Despite having > 5 million VMS records (timestamps and vessel locations), this study was as much about understanding and managing data errors as it was about characterizing trips. Missing VMS records were pervasive and they strongly influenced our approach. To understand implications of missing data on inference, we simulated removal of VMS records from trips. Removal of records straightened (i.e., shortened) vessel trajectories, and travel distances were underestimated, on average, by 1.5–13.4% per trip. Despite this bias, VMS proved robust for trip characterization and for improved quality control of human-recorded data. Our scrutiny of human-reported and VMS data advanced our understanding of the potential utility and challenges facing VMS users globally. PMID:27788174

  6. NEWS: A trip to CERN

    NASA Astrophysics Data System (ADS)

    Ellison, A. D.

    2000-07-01

    the canteen. Over lunch we mixed with physicists of many different nationalities and backgrounds. Figure 1 Figure 1. In the afternoon we visited Microcosm, the CERN visitors centre, and the LEP control room and also the SPS. Here the students learned new applications for much of the physics of standing waves and resonance that they had been taught in the classroom. Later that night, we visited a bowling alley where momentum and collision theory were put into practice. The following morning we returned to CERN and visited the large magnet testing facility. Here again physics was brought to life. We saw superconducting magnets being assembled and tested and the students gained a real appreciation of the problems and principles involved. The afternoon was rounded off by a visit to a science museum in Geneva - well worth a visit, as some of us still use some of the apparatus on display. Friday was our last full day so we visited Chamonix in the northern Alps. In the morning, we ascended the Aiguille de Midi - by cable car. Twenty minutes and 3842 m later we emerged into 50 km h-1 winds and -10 °C temperature, not counting the -10 °C wind chill factor. A crisp packet provided an unusual demonstration of the effects of air pressure (figure 2). Figure 2 Figure 2. The views from the summit were very spectacular though a few people experienced mild altitude sickness. That afternoon the party went to the Mer de Glace. Being inside a 3 million year-old structure moving down a mountain at 3 cm per day was an interesting experience, as was a tot of whisky with 3 million year-old water. Once again the local scenery was very photogenic and the click and whirr of cameras was a constant background noise. Saturday morning saw an early start for the long drive home. Most students - and some staff - took the opportunity to catch up on their sleep. Thanks are due to many people without whom the trip would never have taken place. Anne Craige, Stuart Williams

  7. 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…

  8. Fellows in the Middle: Fabulous Field Trips

    NASA Astrophysics Data System (ADS)

    West, Mary Lou

    2008-05-01

    Montclair State University's NSF GK-12 Program focuses on grades 7 and 8 in five urban public school districts in northern New Jersey. Each year four fieldtrips are taken by the students, middle school teachers, and graduate student Fellows. Many interdisciplinary hands-on lessons are written for use before, during and after each trip with this year's theme of Earth history. The Sterling Hill Mine trip evoked lessons on geology, economics, crystal structure, density, and pH. A virtual trip (webcam link) to scientists in the rainforest of Panama prompted critical thinking, categorizing layers and animals, and construction of model food webs. In the field trip to the NJ School of Conservation the students will build model aquifers, measure tree heights, and measure stream flow to compare to their Hackensack River. Finally the students will travel to MSU for a Math/Science Day with research talks, lab tours, hands-on activities, and a poster session. In January 2008 seventeen teachers, Fellows, and grant personnel took a field trip to China to set up collaborations with researchers and schools in Beijing and Xi'an, including the Beijing Ancient Observatory. All field trips are fabulous! Next year (IYA) our theme will be planetary science and will feature field trips to the Newark Museum's Dreyfuss Planetarium, BCC Buehler Challenger & Science Center, and star parties. We look forward to invigorating middle school science and mathematics with exciting astronomy. Funded by NSF #0638708

  9. 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.

  10. Driver sleepiness and risk of motor vehicle crash injuries: A population-based case control study in Fiji (TRIP 12)☆

    PubMed Central

    Herman, Josephine; Kafoa, Berlin; Wainiqolo, Iris; Robinson, Elizabeth; McCaig, Eddie; Connor, Jennie; Jackson, Rod; Ameratunga, Shanthi

    2014-01-01

    Introduction Published studies investigating the role of driver sleepiness in road crashes in low and middle-income countries have largely focused on heavy vehicles. We investigated the contribution of driver sleepiness to four-wheel motor vehicle crashes in Fiji, a middle-income Pacific Island country. Method The population-based case control study included 131 motor vehicles involved in crashes where at least one person died or was hospitalised (cases) and 752 motor vehicles identified in roadside surveys (controls). An interviewer-administered questionnaire completed by drivers or proxies collected information on potential risks for crashes including sleepiness while driving, and factors that may influence the quantity or quality of sleep. Results Following adjustment for confounders, there was an almost six-fold increase in the odds of injury-involved crashes for vehicles driven by people who were not fully alert or sleepy (OR 5.7, 95%CI: 2.7, 12.3), or those who reported less than 6 h of sleep during the previous 24 h (OR 5.9, 95%CI: 1.7, 20.9). The population attributable risk for crashes associated with driving while not fully alert or sleepy was 34%, and driving after less than 6 h sleep in the previous 24 h was 9%. Driving by people reporting symptoms suggestive of obstructive sleep apnoea was not significantly associated with crash risk. Conclusion Driver sleepiness is an important contributor to injury-involved four-wheel motor vehicle crashes in Fiji, highlighting the need for evidence-based strategies to address this poorly characterised risk factor for car crashes in less resourced settings. PMID:23830198

  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. 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

  13. Giving Students Control over Their Learning; from Self-guided Museum Visits and Field Trips to Using Scanning Technology to Link Content to Earth Samples

    NASA Astrophysics Data System (ADS)

    Kirkby, K. C.; Phipps, M.

    2011-12-01

    While it may seem counterintuitive, sometimes stepping back is one of the more effective pedagogical approaches instructors can make. On museum visits, an instructor's presence fundamentally alters students' experiences and can curtail student learning by limiting questions or discouraging students from exploring their own interests. Students often rely on the instructor and become passive observers, rather than engaged learners. As an alternative to instructor-led visits, self-guided student explorations of museum exhibits proved to be both popular and pedagogically effective. On pre-instruction and post-instruction surveys, these ungraded, self-guided explorations match or exceed the efficacy of traditional graded lab instruction and completely eclipse gains normally achieved by traditional lecture instruction. In addition, these explorations achieve the remarkable goal of integrating undergraduate earth science instruction into students' social lives. Based on the success of the self-guided museum explorations, this fall saw the debut of an attempt to expand this concept to field experiences. A self-guided student field exploration of Saint Anthony Falls focuses on the intersections of geological processes with human history. Students explore the waterfalls' evolution, its early interpretation by 18th and 19th century Dakota and Euro-America societies, and its subsequent social and economic impacts on Upper Midwest societies. Self-guided explorations allow students to explore field settings on their own or with friends and family in a more relaxed manner. At the same time, these explorations give students control over, and responsibility for, their own learning - a powerful pedagogical approach. Student control over their learning is also the goal of an initiative to use scanning technologies, such as linear bar codes, 2D barcodes and radio-frequency identification (RFID), to revolutionize sample identification and study. Scanning technology allows students to

  14. 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

  15. TRIP-Br1 oncoprotein inhibits autophagy, apoptosis, and necroptosis under nutrient/serum-deprived condition

    PubMed Central

    Duan, Jingjing; Lee, Soonduck; Kim, Kyeri; Park, Yeonji; Yang, Young; Kim, Keun-Il; Lim, Jong-Seok; Cheon, Chung-Il; Kang, Young-Sook; Lee, Myeong-Sok

    2015-01-01

    TRIP-Br1 oncogenic protein has been shown to have multiple biological functions in cells. In this study, we demonstrate that TRIP-Br1 functions as an oncoprotein by inhibiting autophagy, apoptosis, and necroptosis of cancer cells and eventually helping them to survive under the nutrient/serum starved condition. TRIP-Br1 expression level was significantly increased in conditions with low levels of nutrients. Nutrient depleted conditions were induced by culturing cancer cells until they were overcrowded with high cell density or in media deprived of glucose, amino acids, or serum. Among them, serum starvation significantly enhanced the expression of TRIP-Br1 only in all tested breast cancer cell lines (MCF7, MDA-MB-231, T47D, MDA-MB-435, Hs578D, BT549, and MDA-MB-435) but not in the three normal cell lines (MCF10A, HfCH8, and NIH3T3). As compared with the control cells, the introduction of TRIP-Br1 silencing siRNA into MCF7 and MDA-MB-231 cells accelerated cell death by inducing apoptosis and necroptosis. In this process, TRIP-Br1 confers resistance to serum starvation-induced cell deaths by stabilizing the XIAP protein and inhibiting cellular ROS production. Moreover, our data also show that the intracellular increase of TRIP-Br1 protein resulting from serum starvation seems to occur in part through the blockage of PI3K/AKT signaling pathway. PMID:26334958

  16. Control over phase behavior and solution structure of hairy-rod polyfluorene by means of side-chain length and branching.

    PubMed

    Knaapila, M; Stepanyan, R; Torkkeli, M; Garamus, V M; Galbrecht, F; Nehls, B S; Preis, E; Scherf, U; Monkman, A P

    2008-05-01

    We present guidelines on how the solution structure of pi -conjugated hairy-rod polyfluorenes is controlled by the side-chain length and branching. First, the semiquantitative mean-field theory is formulated to predict the phase behavior of the system as a function of side-chain beads (N). The phase transition at N=N{ *} separates a lyotropic phase with solvent coexistence (NN{ *}). The membrane phase transforms into the isotropic phase of dissolved rodlike polymers at the temperature T_{mem}{ *}(N), which decreases both with N and with the degree of side-chain branching. This picture is complemented by polymer demixing with the transition temperature T_{IN}{ *}(N), which decreases with N . For NN{ *}, stable membranes are predicted for T_{IN}{ *}controlled by (9,9-dioctylfluorene)/(9,9-bis(2-ethylhexyl)fluorene) (F8/F2/6) random copolymers. The proportion of F8 to F2/6 repeat units was 100:0, 95:5, 90:10, 50:50, and 0:100. In accordance with the theory, lyotropic, membrane, and isotropic phases with the corresponding phase transitions were observed. For NN{ *}. T_{mem}{ *}(N) decreases from 340 K to 280 K for N > or = 8 . For copolymers, the membrane phase is found when the fraction of F8 units is at least 90%, T_{mem}{ *} decreasing with this fraction. The membrane phase contains three material types: loose sheets of two polymer layers, a better packed beta phase, and dissolved polymer. For N > or = 7 and T

  17. The Vo-Ag Spring Educational Trip

    ERIC Educational Resources Information Center

    Fanning, T. D.

    1977-01-01

    A vocational agriculture teacher discusses values, planning procedures, and logistics of an annual 6-day trip in which 40 Future Farmers of America (FFA) members visit farms, ranches, agribusiness units, and other points of interest to rural oriented youth. (JT)

  18. 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.

  19. 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

  20. Cybertrips in Social Studies. Online Field Trips for All Ages.

    ERIC Educational Resources Information Center

    Mandel, Scott

    The Internet can take students on virtual field trips to anywhere earth, under the seas, out in space, or back in time. This book demonstrates how teachers can use the Internet to take students on field trips. Composed of two parts, part 1, "Preparing for the Trip," discusses the background of virtual field trips what they are, and why…

  1. 28 CFR 570.42 - Non-medical escorted trips.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Non-medical escorted trips. 570.42... RELEASE COMMUNITY PROGRAMS Escorted Trips § 570.42 Non-medical escorted trips. (a) Non-medical escorted trips allow an inmate to leave the institution under staff escort for approved, non-medical...

  2. 28 CFR 570.41 - Medical escorted trips.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Medical escorted trips. 570.41 Section... COMMUNITY PROGRAMS Escorted Trips § 570.41 Medical escorted trips. (a) Medical escorted trips are intended to provide an inmate with medical treatment not available within the institution. There are two...

  3. Field Trips as Valuable Learning Experiences in Geography Courses

    ERIC Educational Resources Information Center

    Krakowka, Amy Richmond

    2012-01-01

    Field trips have been acknowledged as valuable learning experiences in geography. This article uses Kolb's (1984) experiential learning model to discuss how students learn and how field trips can help enhance learning. Using Kolb's experiential learning theory as a guide in the design of field trips helps ensure that field trips contribute to…

  4. Improvement in Jc performance below liquid nitrogen temperature for SmBa2Cu3Oy superconducting films with BaHfO3 nano-rods controlled by low-temperature growth

    NASA Astrophysics Data System (ADS)

    Miura, S.; Yoshida, Y.; Ichino, Y.; Xu, Q.; Matsumoto, K.; Ichinose, A.; Awaji, S.

    2016-01-01

    For use in high-magnetic-field coil-based applications, the critical current density (Jc) of REBa2Cu3Oy (REBCO, where RE = rare earth) coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the Jc for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO3 (BHO) nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique (Ts = 720 °C film). The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1) × 103 μm-2 of small (diameter: 4 ± 1 nm), discontinuous nano-rods that grew in various directions, was obtained. In Jc measurements, the Jc of the Ts = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The Jcmin (6.4 MA/cm2) of the former was more than 6 times higher than that (1.0 MA/cm2) of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m3 was realized; this value was comparable to the highest value recorded, to date.

  5. 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.

  6. Analysis of electric vehicle's trip cost without late arrival

    NASA Astrophysics Data System (ADS)

    Leng, Jun-Qiang; Zhao, Lin

    2017-03-01

    In this paper, we use a car-following model to study each electric vehicle's trip cost and the corresponding total trip cost without late arrival. The numerical result show that the electricity cost has significant effects on each electric vehicle's trip cost and the corresponding total trip costs and that the effects are dependent on its time headway at the origin, but the electricity cost has no prominent effects on the minimum value of the system's total trip cost.

  7. Integrated control of transporter endocytosis and recycling by the arrestin-related protein Rod1 and the ubiquitin ligase Rsp5

    PubMed Central

    Becuwe, Michel; Léon, Sébastien

    2014-01-01

    After endocytosis, membrane proteins can recycle to the cell membrane or be degraded in lysosomes. Cargo ubiquitylation favors their lysosomal targeting and can be regulated by external signals, but the mechanism is ill-defined. Here, we studied the post-endocytic trafficking of Jen1, a yeast monocarboxylate transporter, using microfluidics-assisted live-cell imaging. We show that the ubiquitin ligase Rsp5 and the glucose-regulated arrestin-related trafficking adaptors (ART) protein Rod1, involved in the glucose-induced internalization of Jen1, are also required for the post-endocytic sorting of Jen1 to the yeast lysosome. This new step takes place at the trans-Golgi network (TGN), where Rod1 localizes dynamically upon triggering endocytosis. Indeed, transporter trafficking to the TGN after internalization is required for their degradation. Glucose removal promotes Rod1 relocalization to the cytosol and Jen1 deubiquitylation, allowing transporter recycling when the signal is only transient. Therefore, nutrient availability regulates transporter fate through the localization of the ART/Rsp5 ubiquitylation complex at the TGN. DOI: http://dx.doi.org/10.7554/eLife.03307.001 PMID:25380227

  8. 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.

  9. 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.

  10. 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.

  11. Experimental analysis of liquid-metal reactor scram rod kinematic characteristics

    NASA Astrophysics Data System (ADS)

    Konovalenko, F. D.; Kondrashov, S. I.

    2017-01-01

    This article represents the results of computational and experimental research of liquid-metal research reactor control rod kinematics. In this research liquid-metal coolant (sodium) was simulated by water. Investigation of control rod scram-mode movement duration and investigation of velocity of movable parts near the bump of damper are the purposes of this research. Also mathematic simulation of control rod movement in scram mode was performed. Computational results for some modes of water circulation comply with experimental results well. Results of this work will be used for tests of scram rod drive of above-named research reactor. It will significantly simplify the scram rod drive testing stand construction.

  12. 41 CFR 301-71.106 - Who must sign a trip-by-trip authorization?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.106 Who must sign a trip-by-trip authorization? The... acceptance of the payment. Travel expenses related to attendance at a conference A senior agency...

  13. 41 CFR 301-71.106 - Who must sign a trip-by-trip authorization?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.106 Who must sign a trip-by-trip authorization? The... acceptance of the payment. Travel expenses related to attendance at a conference A senior agency...

  14. 41 CFR 301-71.106 - Who must sign a trip-by-trip authorization?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.106 Who must sign a trip-by-trip authorization? The... acceptance of the payment. Travel expenses related to attendance at a conference A senior agency...

  15. 41 CFR 301-71.106 - Who must sign a trip-by-trip authorization?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.106 Who must sign a trip-by-trip authorization? The... acceptance of the payment. Travel expenses related to attendance at a conference A senior agency...

  16. 41 CFR 301-71.106 - Who must sign a trip-by-trip authorization?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS Travel Authorization § 301-71.106 Who must sign a trip-by-trip authorization? The... acceptance of the payment. Travel expenses related to attendance at a conference A senior agency...

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. Comparing Single Versus Double Screw-Rod Anterior Instrumentation for Treating Thoracolumbar Burst Fractures with Incomplete Neurological Deficit: A Prospective, Randomized Controlled Trial

    PubMed Central

    Yu, Yu; Wang, Juan; Shao, Gaohai; Wang, Qunbo; Li, Bo

    2016-01-01

    Background Following a thoracolumbar burst fracture (TCBF), anterior screw-rods apply pressure upon the graft site. However, there is limited evidence comparing single screw-rod anterior instrumentation (SSRAI) to double screw-rod anterior instrumentation (DSRAI) for TCBFs. Our objective was to compare SSRAI versus DSRAI for TCBFs with incomplete neurological deficit. Material/Methods A total of 51 participants with T11-L2 TCBFs (AO classification: A3) were randomly assigned to receive SSRAI or DSRAI. Key preoperative, perioperative, and postoperative data were collected. Statistical analysis was conducted to determine the independent factors associated with inferior clinical outcomes, as well as the comparative efficacy of SSRAI and DSRAI. Results There were no significant differences in the key demographic and clinical characteristics between the two groups (all p>0.05). Smoking status was significantly associated with inferior three-month and six-month Denis pain scores (Wald statistic=4.246, p=0.039). Both SSRAI and DSRAI were significantly effective in improving three-month and six-month postoperative degree of kyphosis, three-month and six-month postoperative ASIA impairment scale scores, three-month and six-month postoperative Denis pain score, and three-month and six-month postoperative Denis work score (all p<0.001). Although there were no significant differences between DSRAI and SSRAI with respect to all outcomes (all p>0.05), DSRAI displayed significantly longer operating times, as well as significantly larger operative blood losses (both p<0.001). Conclusions SSRAI may be preferable over DSRAI for TCBFs with incomplete neurological deficit due to its lower operating time and amount of operative blood loss. PMID:27197020

  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. MCMII and the TriP chip

    SciTech Connect

    Juan Estrada et al.

    2003-12-19

    We describe the development of the electronics that will be used to read out the Fiber Tracker and Preshower detectors in Run IIb. This electronics is needed for operation at 132ns bunch crossing, and may provide a measurement of the z coordinate of the Fiber Tracker hits when operating at 396ns bunch crossing. Specifically, we describe the design and preliminary tests of the Trip chip, MCM IIa, MCM IIb and MCM IIc. This document also serves as a user manual for the Trip chip and the MCM.

  7. Notes for Brazil sampling frame evaluation trip

    NASA Technical Reports Server (NTRS)

    Horvath, R. (Principal Investigator); Hicks, D. R. (Compiler)

    1981-01-01

    Field notes describing a trip conducted in Brazil are presented. This trip was conducted for the purpose of evaluating a sample frame developed using LANDSAT full frame images by the USDA Economic and Statistics Service for the eventual purpose of cropland production estimation with LANDSAT by the Foreign Commodity Production Forecasting Project of the AgRISTARS program. Six areas were analyzed on the basis of land use, crop land in corn and soybean, field size and soil type. The analysis indicated generally successful use of LANDSAT images for purposes of remote large area land use stratification.

  8. 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

  9. On the Merits of "Unusual Field Trips."

    ERIC Educational Resources Information Center

    Howarth, Dean E.

    1999-01-01

    Describes the organization and completion of a scientific field trip for a group of high school physics students that was organized primarily around a study of the Manhattan Project. The group visited the Trinity site, Los Alamos, several museums, and the National Radio Astronomy Observatory Very Large Array. Contact information for the various…

  10. Helping Children Form Connections through Field Trips

    ERIC Educational Resources Information Center

    Boyce, Carol Gratsch

    2006-01-01

    One of the most important things early childhood professionals can do for children is to help them form connections that promote the development of confidence and self-esteem, encourage the risk-taking that is needed to try new things, and contribute to a sense of well-being and belonging. Field trips are a wonderful way to foster these…

  11. Class Trips in Cyberspace: No Passports Required.

    ERIC Educational Resources Information Center

    Holzberg, Carol S.

    1996-01-01

    Describes examples of electronic field trips for elementary and secondary school students taking place during the 1996-97 school year. Topics include Mayan civilization, wildlife migration, geothermal hot spots, Antarctica, sailboat voyages, baseball and math, viruses, Hong Kong, and offerings from National Geographic. (LRW)

  12. School Trips: Are They Worth the Effort?

    ERIC Educational Resources Information Center

    Johnston, Robert

    2015-01-01

    Even the most basic of school trips will require booking places, arranging transport, writing to parents, collecting payments, planning activities, producing worksheets and, of course, endless risk assessments. It always leaves teachers wondering: "is it really worth all this effort?" Robert Johnston believes that every teacher should…

  13. Trip Leaders Guide. Outdoor Expeditions and Classes.

    ERIC Educational Resources Information Center

    Leister, Bob

    Written to help teachers or leaders plan and lead field trips, excursions, or expeditions which stimulate a motivation to positive action, this pamphlet provides assistance in conducting learning experiences outside the classroom. Topics and subtopics discussed include: (1) Campsites: selection; firebuilding; knives, axes, saws; neat campsites;…

  14. 9 Tips for Affordable Student Trips

    ERIC Educational Resources Information Center

    Adams, Jonathan

    2013-01-01

    The trick to having a successful and affordable trip is planning ahead and planning thoroughly. Keep the spirits high and the costs low by following a well-traveled ensemble director's suggestions as presented in this article. These tips include finding local attractions that are unique to the city that the group will be visiting, looking at…

  15. Reconceptualizing Electronic Field Trips: A Deweyian Perspective

    ERIC Educational Resources Information Center

    Cassady, Jerrell C.; Mullen, Laurie J.

    2006-01-01

    Electronic field tripping is a relatively new form of large-scale distance education that attempts to provide contextually rich learning materials embedded within a coherent educational content base. Using Dewey's (1943) framework for the natural learning impulses of children, we describe the potential pedagogical benefits afforded by electronic…

  16. The Educational Value of Field Trips

    ERIC Educational Resources Information Center

    Greene, Jay P.; Kisida, Brian; Bowen, Daniel H.

    2014-01-01

    The school field trip has a long history in American public education. For decades, students have piled into yellow buses to visit a variety of cultural institutions, including art, natural history, and science museums, as well as theaters, zoos, and historical sites. Schools gladly endured the expense and disruption of providing field trips…

  17. Field Trip to a Rocky Shore.

    ERIC Educational Resources Information Center

    Maine Univ., Orono. Cooperative Extension Service.

    Field trip activities designed for use on Maine's coast are provided, with brief definitions of the major physical zones to be found in this area. An introduction to the study of zonation of plants and animals living on the rocky shore is presented along with a list of the materials needed and the procedures to be followed when making a study of…

  18. Field Trips: Liability Issues and Best Practices

    ERIC Educational Resources Information Center

    McGinnis, Michelle H.; Getskow, Veronica; Dicker, Brian S.

    2011-01-01

    A field trip for preschool children can be a rewarding experience, but if not properly planned and executed it can be a legal nightmare for teachers and owners. This article will take teachers through a hypothetical outing. If one spots mistakes before the authors highlight them, great, and if not, one will learn some fine points during this…

  19. Take a Field Trip Close to Home.

    ERIC Educational Resources Information Center

    Wood, Jacalyn K.

    1986-01-01

    Describes a simple field trip taken by fourth-grade students to a local park. Aided by volunteers, students go through four learning stations dealing with rock studies, tree identification, following directions (mapping), and observation skills. Presite and postsite activities are discussed. (TW)

  20. 45 CFR 1310.20 - Trip routing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false Trip routing. 1310.20 Section 1310.20 Public Welfare Regulations Relating to Public Welfare (Continued) OFFICE OF HUMAN DEVELOPMENT SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION FOR CHILDREN, YOUTH AND FAMILIES, HEAD...

  1. 45 CFR 1310.20 - Trip routing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Trip routing. 1310.20 Section 1310.20 Public Welfare Regulations Relating to Public Welfare (Continued) OFFICE OF HUMAN DEVELOPMENT SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION FOR CHILDREN, YOUTH AND FAMILIES, HEAD...

  2. 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.

  3. Mars rapid round trip mission design

    NASA Astrophysics Data System (ADS)

    Sarzi Amade', Nicola

    The present research is divided in two parts. The first part is a well defined mathematical problem, with exact rules and results, in which the basic constraints for interplanetary round trip travels are used to calculate an interplanetary train schedule (ITS) of missions to Mars, in the general case of orbits with non-zero eccentricity and non-zero inclination. Several possible options for round trip travels to Mars are considered. In particular, options at high energy, which allow rapid round trip missions, are discussed. These options have important applications for human travels to Mars. The second part of the research is about systems engineering aspects, which are intrinsically less exact, since they can change with time due, for example, to technology development or economic and political factors. For the case of a selected human rapid round trip mission to Mars, the development of a mission architecture, an assessment of the masses involved in the mission (such as the initial masses required in LEO), an estimate of the necessary number of launches, and a preliminary analysis of the radiation protection requirements, are performed. The main problem that justifies the existence of basic constraints for round trip missions is that by increasing the DeltaV of a mission, in general the total round trip time does not vary much, because a higher DeltaV can only reduce the transfer time and it simply increases the stay-time on the target planet. However, if the DeltaV is increased beyond a well-defined level, the total round trip time has a sudden drop in duration that makes fast round trips possible. This is due to the fact that the traveler can go back before the home planet makes one extra revolution around the Sun. For a sufficiently high DeltaV, a round trip to Mars can change in duration from 2.7 years to about 5 months. For Mars missions, the round trip times are calculated for different DeltaV's and for different transfer trajectories (T1, T2, etc.). An

  4. The Use of Experiential Education and Field Trips for Learning

    ERIC Educational Resources Information Center

    Gillett, Jason

    2011-01-01

    The purpose of my action research is to create meaningful virtual field trips that give students many of the same benefits as actual field trips. Since educational budget cuts are preventing students from participating in real field trips there needs to be an alternative way to deliver that content. I hope to demonstrate how I am improving my…

  5. Revisiting Virtual Field Trips: Perspectives of College Science Instructors

    ERIC Educational Resources Information Center

    Lei, Simon A.

    2015-01-01

    Field trips are an important component of upper undergraduate and graduate-level science courses, especially in the fields of biology, geoscience, and environmental science. Field trips can provide a new perspective to a course's content and quality. Science field trips can facilitate active student learning, yet often can be constrained by time,…

  6. Probabilistic methods in a study of trip setpoints

    SciTech Connect

    Kaulitz, D. E.

    2012-07-01

    Most early vintage Boiling Water Reactors have a high head and high capacity High Pressure Coolant Injection (HPCI) pump to keep the core covered following a loss of coolant accident (LOCA). However, the protection afforded by the HPCI pump for mitigating a LOCA introduces the potential that a spurious start of the HPCI pump could oversupply the reactor vessel and lead to an automatic trip of the main turbine due to high water level. A turbine trip and associated increase in moderator density could challenge the bases of fuel integrity operating limits. To prevent turbine trip during spurious operation of the HPCI pump, the reactor protection system includes instrumentation and logic to sense high water level and automatically trip the HPCI pump prior to reaching the turbine trip setpoint. This paper describes an analysis that was performed to determine if existing reactor vessel water level trip instrumentation, logic and setpoints result in a high probability that the HPCI pump will trip prior to actuation of the turbine trip. Using nominal values for the initial water level and for the HPCI pump and turbine trip setpoints, and using the probability distribution functions for measurement uncertainty in these setpoints, a Monte Carlo simulation was employed to determine probabilities of successfully tripping the HPCI pump prior to tripping of the turbine. The results of the analysis established that the existing setpoints, instrumentation and logic would be expected to reliably prevent a trip of the main turbine. (authors)

  7. 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.

  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. 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.

  10. Using Virtual Field Trips to Connect Students with University Scientists: Core Elements and Evaluation of zipTrips[TM

    ERIC Educational Resources Information Center

    Adedokun, Omolola A.; Hetzel, Kristin; Parker, Loran Carleton; Loizzo, Jamie; Burgess, Wilella D.; Robinson, J. Paul

    2012-01-01

    Physical field trips to scientists' work places have been shown to enhance student perceptions of science, scientists and science careers. Although virtual field trips (VFTs) have emerged as viable alternatives (or supplements) to traditional physical fieldtrips, little is known about the potential of virtual field trips to provide the same or…

  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. Field trips along the Geological Transpyrenean Road

    NASA Astrophysics Data System (ADS)

    Burgio, Marion; Dekeyser, Dominique; Richert, Jean Paul; Gruneisen, Pierre; Vazquez-Prada, Diego; Lacazedieu, Annie

    2015-04-01

    GeolVal association, www.geolval.fr , in collaboration with Geoambiente association, created a serie of pedagogical explanations about Pyrenees landscapes along the road from France to Spain, linking the towns of Pau, Oloron,Jaca and Mallos de Riglos. It was a ten years work that lasted in 2008. http://www.routetranspyreneenne.com/home_f.php We can now use this "treasure" with tourists, students and mix some landscapes explanations from a road site with a little field trip along mountain in order to "touch" the rocks. We are working about the importance of field in the way the students understand geosciences and try to organize field trips that aim to simplify and make concrete some key concepts. We also began an interactive software version of this work, presented through a pilot application, made in collaboration with Total petroleum firm.

  13. 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.

  14. 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

  15. Nuclear reactor control apparatus

    DOEpatents

    Sridhar, Bettadapur N.

    1983-11-01

    Nuclear reactor core safety rod release apparatus comprises a control rod having a detent notch in the form of an annular peripheral recess at its upper end, a control rod support tube for raising and lowering the control rod under normal conditions, latches pivotally mounted on the control support tube with free ends thereof normally disposed in the recess in the control rod, and cam means for pivoting the latches out of the recess in the control rod when a scram condition occurs. One embodiment of the invention comprises an additional magnetically-operated latch for releasing the control rod under two different conditions, one involving seismic shock.

  16. Evaluation of pediatric community field trips.

    PubMed

    Molnar, E T; Knasel, A L

    1987-05-01

    A field trip program for junior medical students on a pediatric clinical clerkship acquainted students with the care of normal and handicapped children in community settings of school, day care center, residential treatment, or diagnostic facilities.A program evaluation by pre and post-trip survey demonstrated a positive change in students' knowledge and attitude in general, which was unaffected by such factors as sex, previous experience in a medical setting, and previous experience with handicapped children.As an integral part of the pediatric clerkship, the field trip appears to have been a positive experience for students, as it met their educational and emotional needs. Subjective evaluation indicated that many students formed insightful and compassionate judgments about handicapped children.Although the increase in knowledge and sensitivity of the students, as reflected in the pre-and post-test, was not statistically significant, the benefit to the students, to the personnel of the agencies, and ultimately to the children and families with whom they dealt during their professional careers was important.

  17. Evaluation of Pediatric Community Field Trips

    PubMed Central

    Molnar, Eva T.; Knasel, Anne L.

    1987-01-01

    A field trip program for junior medical students on a pediatric clinical clerkship acquainted students with the care of normal and handicapped children in community settings of school, day care center, residential treatment, or diagnostic facilities. A program evaluation by pre and post-trip survey demonstrated a positive change in students' knowledge and attitude in general, which was unaffected by such factors as sex, previous experience in a medical setting, and previous experience with handicapped children. As an integral part of the pediatric clerkship, the field trip appears to have been a positive experience for students, as it met their educational and emotional needs. Subjective evaluation indicated that many students formed insightful and compassionate judgments about handicapped children. Although the increase in knowledge and sensitivity of the students, as reflected in the pre-and post-test, was not statistically significant, the benefit to the students, to the personnel of the agencies, and ultimately to the children and families with whom they dealt during their professional careers was important. PMID:3586049

  18. Fast round-trip Mars trajectories

    NASA Technical Reports Server (NTRS)

    Wilson, Sam

    1990-01-01

    This paper is concerned with the effect of limiting the overall duration or else the one-way flight time of a round trip to Mars, as reflected in the sum of impulsive velocity increments required of the spacecraft propulsion system. Ignition-to-burnout mass ratios for a hypothetical single stage spacecraft, obtained from the rocket equation by combining these delta-V sums with appropriate values of specific impulse, are used to evaluate the relative effectiveness of four high-thrust propulsion alternatives. If the flight crew goes to the surface of Mars and stays there for the duration of their stopover, it is much cheaper (in terms of delta-V) to minimize their zero-g exposure by limiting the interplanetary transit time of a conjunction-class mission (round trip time = 800-1000 days, Mars stopover = 450-700 days) than to impose the same limit on an opposition-class mission (round trip time less than 600 days, stopover = 40 days). Using solid-core nuclear thermal propulsion to fly a conjunction-class mission, for a moderate mass penalty the interplanetary transit time (each way) probably could be limited to something in the range of 4 to 6 months, depending on the launch year.

  19. Scrutinized: The TRIPS Agreement and Public Health

    PubMed Central

    Subhan, Junaid

    2006-01-01

    SUMMARY The World Trade Organization’s (WTO’s) Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) of 1994 seeks to implement a uniform set of intellectual property protection across member nations to provide greater stability in international economic relations. Critics argue that the TRIPS agreement provides unnecessarily strong protection of intellectual property rights which serves to prevent the ill in developing nations from having access to affordable essential medications. The first recommendation that this paper makes is to provide two sets of intellectual property protection, one that applies to essential medications such as AIDS drugs and certain antibiotics and another that applies to drugs that treat non-life threatening conditions. The second recommendation builds upon the first recommendation: if two sets of intellectual property protection legislation are enacted, patents on essential medications should be restricted to patents on processes rather than the product itself. The third recommendation seeks to amend the language of the TRIPS agreement to make it obligatory for member nations to implement provisions on compulsory licensing within their domestic legislation. PMID:18523624

  20. Measuring the relationship between sportfishing trip expenditures and anglers’ species preferences

    USGS Publications Warehouse

    Long, James M.; Melstrom, Richard T.

    2016-01-01

    We examined the relationship between fishing trip expenditures and anglers’ species preferences from a survey of Oklahoma resident anglers conducted in 2014. Understanding patterns in fishing trip expenditures is important because a significant share of state wildlife agency revenue comes from taxes on purchases of fishing equipment. Presently, there is little research that addresses the question of how spending levels vary within groups of sportspersons, including anglers. We used regression analysis to identify a relationship between trip spending and several preference variables, and included controls for other characteristics of fishing trips, such as location, party size, and duration. We received 780 surveys for a response rate of 26%, but only 506 were useable due to missing data or nonfishing responses. Average trip expenditures were approximately US$140, regardless of species preferences, but anglers who preferred to fish for trout and black bass tended to spend more than those who preferred to fish for catfish and panfish. These results were even more pronounced when location was considered, those who last fished at lakes spending more than those who fished at rivers or ponds. The results underscore the differences in spending among anglers with different preferred species and fishing locations.

  1. 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.

  2. 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'.

  3. Impact of the World Trade Organization TRIPS agreement on the pharmaceutical industry in Thailand.

    PubMed Central

    Supakankunti, S.; Janjaroen, W. S.; Tangphao, O.; Ratanawijitrasin, S.; Kraipornsak, P.; Pradithavanij, P.

    2001-01-01

    The 1994 World Trade Organization (WTO) Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) established minimum universal standards in all areas of intellectual property. It is intended to implement these standards globally through a WTO enforcement mechanism. The present article proposes a strategy for alleviating the potentially negative impact of TRIPS in Thailand in relation to the following: purchasers; prescribers and dispensers; producers; products; price control; patent-to-third-party; parallel imports; power of the customer; patentable new drugs; personnel; and prevention policies. The following TRIPS provisions are pertinent to the pharmaceutical industry in Thailand: the limited term of product and process patents; the conditions of protection; and the broad scope for compulsory licensing and enforcement procedures in the national patent system. PMID:11417042

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. Austenite Stability and Tensile Properties of Warm-Extruded Trip Steels

    DTIC Science & Technology

    1976-05-01

    ductility in war-extruded TRIP steel. The austenite stability could be adjusted, however, by a tempering treatment to remove some carbon from solid ... solution , giving tensile properties equivalent or superior to those obtained by warm rolling. Difficulties in alloy composition control or temperature

  9. Microprocessor tester for the treat upgrade reactor trip system

    SciTech Connect

    Lenkszus, F.R.; Bucher, R.G.

    1984-01-01

    The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. In addition, a programmable Automated Reactor Control System (ARCS) will permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety system is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations.

  10. Effect of pressurizer sizing on the turbine trip transient

    SciTech Connect

    Brownson, D.A.; Baratta, A.J.; Robinson, G.E.

    1986-10-01

    Following the Three Mile Island accident, a number of suggestions were offered for improving the safety of nuclear power plants. Many of these approaches involve increased dependence on complex and sophisticated safety systems and control technologies. An alternative approach to increased safety is explored; this approach involves the maximization of inherent safety features and minimization of safety and control system action. Specifically, the effects of changing pressurizer size and surge line configuration are examined to determine if the operation of the power-operated relief valve (PORV) could be eliminated during a turbine trip transient in a pressurized water reactor. The study is accomplished using the RETRAN-02 thermal-hydraulic analysis code. The results show that the opening of the PORV could be eliminated if the pressurizer size was doubled and the PORV setpoint increased slightly.

  11. 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

  12. Predictors of trips to food destinations

    PubMed Central

    2012-01-01

    Background Food environment studies have focused on ethnic and income disparities in food access. Few studies have investigated distance travelled for food and did not aim to inform the geographic scales at which to study the relationship between food environments and obesity. Further, studies have not considered neighborhood design as a predictor of food purchasing behavior. Methods Atlanta residents (N = 4800) who completed a travel diary and reported purchasing or consuming food at one of five food locations were included in the analyses. A total of 11,995 food-related trips were reported. Using mixed modeling to adjust for clustering of trips by participants and households, person-level variables (e.g. demographics), neighborhood-level urban form measures, created in GIS, and trip characteristics (e.g. time of day, origin and destination) were investigated as correlates of distance travelled for food and frequency of grocery store and fast food outlet trips. Results Mean travel distance for food ranged from 4.5 miles for coffee shops to 6.3 miles for superstores. Type of store, urban form, type of tour, day of the week and ethnicity were all significantly related to distance travelled for food. Origin and destination environment, type of tour, day of week, age, gender, income, ethnicity, vehicle access and obesity status were all significantly related to visiting a grocery store. Home neighborhood environment, day of week, type of tour, gender, income, education level, age, and obesity status were all significantly related to likelihood of visiting a fastfood outlet. Conclusions The present study demonstrated that people travel sizeable distances for food and this distance is related to urban. Results suggest that researchers need to employ different methods to characterize food environments than have been used to assess urban form in studies of physical activity. Food is most often purchased while traveling from locations other than home, so future studies

  13. Hunton Group core workshop and field trip

    SciTech Connect

    Johnson, K.S.

    1993-12-31

    The Late Ordovician-Silurian-Devonian Hunton Group is a moderately thick sequence of shallow-marine carbonates deposited on the south edge of the North American craton. This rock unit is a major target for petroleum exploration and reservoir development in the southern Midcontinent. The workshop described here was held to display cores, outcrop samples, and other reservoir-characterization studies of the Hunton Group and equivalent strata throughout the region. A field trip was organized to complement the workshop by allowing examination of excellent outcrops of the Hunton Group of the Arbuckle Mountains.

  14. Method of targeted delivery of laser beam to isolated retinal rods by fiber optics.

    PubMed

    Sim, Nigel; Bessarab, Dmitri; Jones, C Michael; Krivitsky, Leonid

    2011-11-01

    A method of controllable light delivery to retinal rod cells using an optical fiber is described. Photo-induced current of the living rod cells was measured with the suction electrode technique. The approach was tested with measurements relating the spatial distribution of the light intensity to photo-induced current. In addition, the ion current responses of rod cells to polarized light at two different orientation geometries of the cells were studied.

  15. Mediating cultural borders during science field trips

    NASA Astrophysics Data System (ADS)

    Lebak, Kimberly

    2007-10-01

    In this paper, I analyze teacher and student roles in the teaching and learning of science at an informal learning center, The Outdoor Classroom. As a white middle class informal learning science teacher, I examine my struggles to teach science to students across boundaries of race, class, gender, and experience with the outdoors during field trips. Through the field trip I did not have the time or face-to-face experience to make sense of the students' culture, see their culture in terms of capital, and align my enactment to benefit their learning. Likewise, the students did not have the time or face-to-face experience with me in order to adapt their cultural capital and build the essential stocks of symbolic and social capital. This research demonstrates how the classroom teacher draws upon previous transactions and emotions to successfully engage her students in practices that promote the participation and learning of science. Through creating culturally adaptive ways of transacting, teachers can provide opportunities for their students to generate positive emotional energy and group solidarity in the learning of science at an informal science center.

  16. 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.

  17. 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...

  18. INSTRUCTIONAL TRIPS, A PROGRAM FOR ENRICHING EDUCATIONAL EXPERIENCE IN THE ELEMENTARY SCHOOLS.

    ERIC Educational Resources Information Center

    FINK, ALLAN; AND OTHERS

    A TEACHER GUIDE FOR FIELD TRIPS IN THE PASADENA, CALIFORNIA, AREA IS PRESENTED. EACH TRIP SHOULD BE PRECEDED BY AN EXPLANATION OF THE PURPOSES OF THE TRIP IN RELATION TO PRESENT COURSE OF STUDY. AS A FOLLOWUP ACTIVITY, DISCUSSION OF IDEAS GAINED DURING THE TRIP SHOULD BE ENCOURAGED. THE RULES, REGULATIONS AND PROCEDURES OF THE TRIP ARE GIVEN. TRIP…

  19. Daily Variations in Spring Break Alcohol and Sexual Behaviors Based on Intentions, Perceived Norms, and Daily Trip Context

    PubMed Central

    Patrick, Megan E.; Lee, Christine M.

    2012-01-01

    Objective: Given the known risks of alcohol use and sexual behavior for college students on Spring Break, this study was designed to document the behaviors and correlates associated with being on a Spring Break trip on a given day (controlling for average time on a trip). Method: Participants were undergraduate students (n = 261; 55% women) who reported that they planned to go on a Spring Break trip. Web-based survey responses before and after Spring Break documented perceived norms, intentions, and actual behavior on each of the 10 days of Spring Break. Results: Students who went on longer trips, who previously engaged in more heavy episodic drinking, or who had greater pre–Spring Break intentions to drink reported greater alcohol use during Spring Break. Similarly, students with greater pre–Spring Break intentions to have sex, greater perceived norms for sex, or more previoussexual partners had greater odds of having sex. On days students were on trips, they had a greater likelihood of having sex, drinking to higher estimated blood alcohol concentrations, consuming more drinks, and reporting perceived drunkenness than on nontrip days, especially if they had intentions to have sex and drink alcohol (and, for models predicting sexual behavior and drunkenness, had greater perceived norms for sex and drinking). Conclusions: Students who went on Spring Break trips engaged in more risk behaviors. In addition, the context of being on a trip on a given day was associated with increased risk, especially if they had stronger intentions and, in some cases, higher perceived norms. Further research is needed to describe the contexts of Spring Break trips and how to intervene effectively. PMID:22630797

  20. Thermal beam distortions in end-pumped Nd:YAG, Nd:GSGG, and Nd:YLF rods

    SciTech Connect

    Pfistner, C.; Weber, R.; Weber, H.P. . Inst. of Applied Physics); Merazzi, S.; Gruber, R. . Centro Svizzero di Calcolo Scientifico)

    1994-07-01

    The thermally induced beam distortion in end-pumped Nd:YAG, Nd: GSGG, and Nd:YLF rods were analyzed and the influence of edge- and face-cooling was investigated. The distributions of temperature, stress, and strain in the crystals were calculated by finite element analysis. Based on these data, the space-resolved changes of the refractive index were determined considering thermal dispersion, surface deformation, and strain-induced birefringence. The resulting optical path difference for one round-trip in the end-pumped rods was integrated numerically. For each rod, the induced thermal lens was determined over the extent of the pump spot radius. The calculations of the optical path difference were experimentally confirmed by investigations using a modified Twyman-Green interferometer with a polarized HeNe probe beam at 633 nm under lasing and nonlasting conditions.

  1. 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).

  2. Managing Health and Safety on International School Trips

    ERIC Educational Resources Information Center

    Hunter-Jones, John; Hunter-Jones, Philippa

    2007-01-01

    Organizing international school trips can be a demanding experience because of the age of the participants, the unfamiliar surroundings and the excitement associated with the foreign trip. As many organizers are full-time teachers, without a background in the travel sector, the pressures can be even greater. The need to anticipate potential risks…

  3. Should You Rule Out Fund Raising, Trips, and Contests?

    ERIC Educational Resources Information Center

    Ross, Stewart L.

    1992-01-01

    Schools need not rule out fund raising, trips, and contests. Well-organized groups of music students washing cars at local gas stations can create more positive publicity and goodwill toward music programs than can hundreds of news releases. Exchange concerts, trips to nearby schools, and competition against a predetermined scale can substitute…

  4. Off-Site Trip Leaders: Selecting Appropriate Staff.

    ERIC Educational Resources Information Center

    Evans, Will

    1996-01-01

    Well-trained off-site trip leaders can turn a trip into a positive educational lesson. American Camping Association standards are referenced, and some personality traits are suggested as criteria for determining the suitability of staff to act responsibly "in loco director." Discusses factors that determine counselor-to-camper ratios,…

  5. Slip, Trip, and Fall Injuries Among Nursing Care Facility Workers

    PubMed Central

    Bell, Jennifer L.; Collins, James W.; Tiesman, Hope M.; Ridenour, Marilyn; Konda, Srinivas; Wolf, Laurie; Evanoff, Bradley

    2015-01-01

    The objective of this research was to describe the slip, trip, and fall injury experience and trends in a population of nursing home workers, identify risk factors for slip, trip, and fall injuries, and develop prevention strategies for slip, trip, and fall hazards. Workers’ compensation injury claims data and payroll data from 1996 through 2003 were obtained from six nursing homes and used to calculate injury incidence rates. Narrative information was used to describe details of slip, trip, and fall events. A total of 86 slip, trip, and fall-related workers’ compensation claims were filed during the 8-year period. Slip, trip, and fall claim rates showed a nonsignificant increase during the 8-year period. Most slips, trips, and falls were attributed to hazards that can be mitigated (e.g., water on the floor or loose cords in a walkway). Nursing home workers experience more slip, trip, and fall-related injury claims than workers in other industries. Preventive programs should be implemented and evaluated in this industry. PMID:23521142

  6. Development of Teacher Attitude Scale towards the Field Trip

    ERIC Educational Resources Information Center

    Tortop, Hasan Said

    2012-01-01

    A field trip is an excursion by group of students with teachers to a place away from classroom such as natural field, science center, and zoo. So, it is an important tool for renewable energy education. This study was carried out to develop a new scale for measuring teacher attitudes towards the field trip. Teacher attitude scale towards the field…

  7. Psychological Sense of Community and Group Cohesion on Wilderness Trips

    ERIC Educational Resources Information Center

    Breunig, Mary; O'Connell, Tim; Todd, Sharon; Young, Anderson; Anderson, Lynn; Anderson, Dale

    2008-01-01

    A primary purpose of many wilderness trip programs is the development of positive interpersonal relationships and group experiences that lead to enhanced sense of community among group members. Although there is anecdotal evidence to support the development of sense of community on wilderness trips, there is little empirical evidence to support…

  8. Collecting Planarians: A Good Choice for a Field Trip.

    ERIC Educational Resources Information Center

    Cha, Heeyoung

    2001-01-01

    Describes a field trip to collect planarians as successful in generating interest in the sciences. This activity is suitable for all grade levels as a field trip or biology lab. Planarians can be easily collected from streams across the United States. Once in the classroom, planaria are easily fed and cared for. (SAH)

  9. In Praise of Off-Season Field Trips. Comments.

    ERIC Educational Resources Information Center

    Butler, David R.; Wilkerson, Forrest D.

    2000-01-01

    Discusses university field courses and field trips. Offers alternatives to summer fieldwork, describing college-level field trips during spring, autumn, and winter. Concludes that the fun of fieldwork is essential and that a dialogue should occur between university instructors and K-12 teachers. (CMK)

  10. The Beginner's Guide to Interactive Virtual Field Trips

    ERIC Educational Resources Information Center

    Zanetis, Jan

    2010-01-01

    For students, field trips can be the best of both worlds: a welcome and exciting break from day-to-day classroom activities and a memorable, real-world experience that will solidify the curriculum in their minds. Unfortunately, the most desirable trips--those to far-away, enticing destinations--have long been inaccessible to all but a select few,…

  11. Toward a Virtual Field Trip Model for the Social Studies

    ERIC Educational Resources Information Center

    Stoddard, Jeremy

    2009-01-01

    In the current state of social studies education, field trips are being cut from many schools' curriculum. While not a true substitution, today's technologies provide some opportunities through virtual field trips (VFTs) to simulate these experiences, engage students in knowledge production and disciplined inquiry, and have interactions with the…

  12. Strategies for Planning an Overseas Field Trip for Young Athletes

    ERIC Educational Resources Information Center

    Hubball, Harry; Robertson, Scott

    2004-01-01

    Overseas field trips, when they are well planned, offer numerous benefits to young athletes. They contribute to player development, and fuel the team's energy and commitment to success. Field trips are enjoyable and exciting breaks from the regular routine of training and competing. The authors recommend strategies for positive results based on…

  13. Field Trips as Cognitive Motivators for High Level Science Learning

    ERIC Educational Resources Information Center

    Hurley, Marlene M.

    2006-01-01

    Using a composite example of field trips from several years of traveling to Yellowstone with high school biology students, the author illustrates how to raise the cognitive level of science instruction and student learning through science field trips. The author examines what teachers can do to raise the level of both teaching and learning in all…

  14. Mechanisms Influencing Student Understanding on an Outdoor Guided Field Trip

    ERIC Educational Resources Information Center

    Caskey, Nourah Al-Rashid

    2009-01-01

    Field trips are a basic and important, yet often overlooked part of the student experience. They provide the opportunity to integrate real world knowledge with classroom learning and student previous personal experiences. Outdoor guided field trips leave students with an increased understanding, awareness and interest and in science. However, the…

  15. Effectiveness of Field Trips in Teaching Groundwater Concepts.

    ERIC Educational Resources Information Center

    Pederson, Darryll T.

    1979-01-01

    The field trip procedures described were devised for use with freshman college students as an alternative to a classroom or laboratory session. Pre-test and post-test of students' knowledge of groundwater concepts show significant change in students' understanding of groundwater occurance and movement following such a trip. (RE)

  16. 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.

  17. Site controlled red-yellow-green light emitting InGaN quantum discs on nano-tipped GaN rods

    NASA Astrophysics Data System (ADS)

    Conroy, M.; Li, H.; Kusch, G.; Zhao, C.; Ooi, B.; Edwards, P. R.; Martin, R. W.; Holmes, J. D.; Parbrook, P. J.

    2016-05-01

    We report a method of growing site controlled InGaN multiple quantum discs (QDs) at uniform wafer scale on coalescence free ultra-high density (>80%) nanorod templates by metal organic chemical vapour deposition (MOCVD). The dislocation and coalescence free nature of the GaN space filling nanorod arrays eliminates the well-known emission problems seen in InGaN based visible light sources that these types of crystallographic defects cause. Correlative scanning transmission electron microscopy (STEM), energy-dispersive X-ray (EDX) mapping and cathodoluminescence (CL) hyperspectral imaging illustrates the controlled site selection of the red, yellow and green (RYG) emission at these nano tips. This article reveals that the nanorod tips' broad emission in the RYG visible range is in fact achieved by manipulating the InGaN QD's confinement dimensions, rather than significantly increasing the In%. This article details the easily controlled method of manipulating the QDs dimensions producing high crystal quality InGaN without complicated growth conditions needed for strain relaxation and alloy compositional changes seen for bulk planar GaN templates.We report a method of growing site controlled InGaN multiple quantum discs (QDs) at uniform wafer scale on coalescence free ultra-high density (>80%) nanorod templates by metal organic chemical vapour deposition (MOCVD). The dislocation and coalescence free nature of the GaN space filling nanorod arrays eliminates the well-known emission problems seen in InGaN based visible light sources that these types of crystallographic defects cause. Correlative scanning transmission electron microscopy (STEM), energy-dispersive X-ray (EDX) mapping and cathodoluminescence (CL) hyperspectral imaging illustrates the controlled site selection of the red, yellow and green (RYG) emission at these nano tips. This article reveals that the nanorod tips' broad emission in the RYG visible range is in fact achieved by manipulating the InGaN QD

  18. 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.

  19. Actuator system history of safety rod lower latch problems review of latch inspection video tapes

    SciTech Connect

    Banks, J.J.

    1992-06-24

    During pre-restart testing the safety rod at position X26-YlO bound after being driven approximately two (2) feet out of the reactor. Subsequently, the rod was manually returned to it's seated position. Inspection of the lower latch showed that the latch locking plunger button (screwed on to the bottom of the plunger shaft and retained by a pin through a hole drilled through the button and the plunger shaft) was missing. The shaft failed through the hole drilled for the retaining pin. The button, with the retaining pin intact, was found lodged between the safety rod upper adapter collar and the top of the safety rod thimble top fitting. Analysis of the safety rod latch and accompanying forest guide tube design provided assurance that this type of failure would not cause binding during the scramming'' of the safety rods. Inspection of all of the K'' safety rod lower latches revealed six other latches with missing plunger buttons, and nine with other non-conformances which required latch replacement. A history search conducted by Reactor Engineering Design, Components Handling Group, is included in this report. The history search shows that latch design modifications, as a part of initial development of the latch system and later to improve the delatching operation, were made from 1950 to 1960. These modifications created a condition where latch damage could occur. Video tapes were made during inspection of the safety rod latches in K area and control rod latches in L area. These tapes were reviewed by Reactor Engineering Design Components Handling engineers. The reviews were used for correlation of latch problems reported by the engineers/mechanics making the inspections. The K area tapes showed inspection of 65 of the 66 safety rod latches. The review of the tapes showed the plunger buttons to be missing from five latches. RED-CH reviewed the L Area video taped inspection of 35 control rod clusters (245 latches). No non-conformances were noted.

  20. Actuator system history of safety rod lower latch problems review of latch inspection video tapes

    SciTech Connect

    Banks, J.J.

    1992-06-24

    During pre-restart testing the safety rod at position X26-YlO bound after being driven approximately two (2) feet out of the reactor. Subsequently, the rod was manually returned to it`s seated position. Inspection of the lower latch showed that the latch locking plunger button (screwed on to the bottom of the plunger shaft and retained by a pin through a hole drilled through the button and the plunger shaft) was missing. The shaft failed through the hole drilled for the retaining pin. The button, with the retaining pin intact, was found lodged between the safety rod upper adapter collar and the top of the safety rod thimble top fitting. Analysis of the safety rod latch and accompanying forest guide tube design provided assurance that this type of failure would not cause binding during the ``scramming`` of the safety rods. Inspection of all of the ``K`` safety rod lower latches revealed six other latches with missing plunger buttons, and nine with other non-conformances which required latch replacement. A history search conducted by Reactor Engineering Design, Components Handling Group, is included in this report. The history search shows that latch design modifications, as a part of initial development of the latch system and later to improve the delatching operation, were made from 1950 to 1960. These modifications created a condition where latch damage could occur. Video tapes were made during inspection of the safety rod latches in K area and control rod latches in L area. These tapes were reviewed by Reactor Engineering Design Components Handling engineers. The reviews were used for correlation of latch problems reported by the engineers/mechanics making the inspections. The K area tapes showed inspection of 65 of the 66 safety rod latches. The review of the tapes showed the plunger buttons to be missing from five latches. RED-CH reviewed the L Area video taped inspection of 35 control rod clusters (245 latches). No non-conformances were noted.

  1. Mechanoresponsive change in photoluminescent color of rod-like liquid-crystalline compounds and control of molecular orientation on photoaligned layer

    NASA Astrophysics Data System (ADS)

    Kondo, Mizuho; Miura, Seiya; Okumoto, Kentaro; Hashimoto, Mayuko; Fukae, Ryohei; Kawatsuki, Nobuhiro

    2014-10-01

    In this paper, we reported novel liquid-crystalline luminophore that switches its photoluminescent color by mechanically grinding. Mechanochromic luminescence (MCL) is expected for mechanical sensor, cellular imaging, detection of microenvironmental changes, and optical memory. In this work, we focused on liquid-crystalline MCL compounds on alignment layer. Controlling the molecular alignment of MCL compounds with photoalignment layer have potential to succeed in functional MCL film such as polarized micropatterned MCL and directional detection of mechanical stimuli. Herein, we prepared asymmetric rodlike MCL compounds containing cyano- and pyridyl molecular terminal and explored their photoluminescence behavior under mechanical stimulus. The cyano terminated compound showed a nematic phase and tuned its photoluminescent color from green to yellow upon grinding, while the pyridyl-terminated compounds that show no mesophase changed its photoluminescent color from blue to green and reverted to its initial color by heating above its melting point. The cyano-terminated MCL was aligned along the orientation direction of photoalignment layer and pyridyl-terminated MCL exhibited uniaxial alignment when it coated on photoaligned film containing carboxylic acid.

  2. Flow in Rotating Serpentine Coolant Passages With Skewed Trip Strips

    NASA Technical Reports Server (NTRS)

    Tse, David G.N.; Steuber, Gary

    1996-01-01

    Laser velocimetry was utilized to map the velocity field in serpentine turbine blade cooling passages with skewed trip strips. The measurements were obtained at Reynolds and Rotation numbers of 25,000 and 0.24 to assess the influence of trips, passage curvature and Coriolis force on the flow field. The interaction of the secondary flows induced by skewed trips with the passage rotation produces a swirling vortex and a corner recirculation zone. With trips skewed at +45 deg, the secondary flows remain unaltered as the cross-flow proceeds from the passage to the turn. However, the flow characteristics at these locations differ when trips are skewed at -45 deg. Changes in the flow structure are expected to augment heat transfer, in agreement with the heat transfer measurements of Johnson, et al. The present results show that trips are skewed at -45 deg in the outward flow passage and trips are skewed at +45 deg in the inward flow passage maximize heat transfer. Details of the present measurements were related to the heat transfer measurements of Johnson, et al. to relate fluid flow and heat transfer measurements.

  3. Student perspectives on their school trips to zoos

    NASA Astrophysics Data System (ADS)

    Davidson, Susan Kay

    This dissertation aimed to explore students' perspectives on their school trips to informal education sites. In particular, what did students think they learned, what did they want to do, what was fun or boring, and how did their trip relate to classroom activities? The two case studies presented here explore these ideas with 11-12-year olds in New Zealand and their class trips to zoos, in contrasting situations: one is a class in which the teacher thoughtfully and explicitly linked the trip to classroom learning both before and after the trip; the other classroom teacher did not. These differences impacted how students thought about their learning and how they valued the trip. Despite the differences, students had similarities in some of their perspectives, particularly in their focus on social interactions with peers and their desire to see the animals at the zoos. This study concludes with recommendations for informal and classroom educators, especially to find out what students are interested in, give them choices, and connect trips to classroom activities.

  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. Advanced transportation concept for round-trip space travel

    NASA Technical Reports Server (NTRS)

    Yen, Chen-Wan L.

    1988-01-01

    A departure from the conventional concept of round-trip space travel is introduced. It is shown that a substantial reduction in the initial load required of the Shuttle or other launch vehicle can be achieved by staging the ascent orbit and leaving fuel for the return trip at each stage of the orbit. Examples of round trips from a low-inclination LEO to a high-inclination LEO and from an LEO to a GEO are used to show the merits of the new concept. Potential problem areas and research needed for the development of an efficient space transportation network are discussed.

  6. 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.

  7. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Peer Pressure Road Trip 2012 - A Report

    NASA Astrophysics Data System (ADS)

    Popnoe, Olivia

    2012-10-01

    Each year since 2005 the Angelo State University SPS ``Peer Pressure Team'' has travelled for a week in May to promote physics and other sciences for grades K-12. This year, the Peer Pressure Team visited schools in West Texas and New Mexico. This was the first year the team has traveled outside of Texas, inspired by the SPS 2012 theme ``Physics Beyond Borders.'' The purpose of the Road Tours is to encourage an interest in science in children in grades K-12 and give experience in presenting and explaining physics to the undergraduate volunteers. The schools attended are carefully selected based on socioeconomic need and an underrepresentation in physics, as well as other sciences. During this week, the Peer Pressure Team saw about 1,500 students over 10 shows. Surveys were given to teachers post-demonstration to have students complete and return so the Team could gauge the effectiveness of the outreach program. In addition, the surveys allow the Team to determine which demonstrations had the most impact. We present the details of this year's road trip with the results and analysis of the survey data.

  15. You Can't Reach for the Stars if You are Tripping Over the Ground! (Preventing Slips, Trips, and Falls)

    NASA Technical Reports Server (NTRS)

    Miller, Darcy; Raysich, Mark; Kirkland, Mary

    2016-01-01

    Although there are very few mishaps related to ground, vehicle or payload processing at the Kennedy Space Center (KSC), employees have experienced a significant number of injuries due to slips, trips, and falls outside of performing flight processing operations. Slips, trips, and falls are major causes of occupational injuries at KSC, the National Aeronautics and Space Administration (NASA), and in general industry. To help KSC employees avoid these injuries, and allow them to be fully productive, KSC launched an initiative in 2013 to reduce slips, trips, and falls. This initiative is based on a four-part model focusing on DATA analysis, HAZARD awareness, PREVENTIVE methods, and BALANCE.

  16. 18. Blacksmith Shop (first floor): view looking north; trip hammer ...

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

    18. Blacksmith Shop (first floor): view looking north; trip hammer and coal bin in background, shears and swage block in foreground - Ben Thresher's Mill, State Aid No. 1, Barnet, Caledonia County, VT

  17. 50 CFR 622.385 - Commercial trip limits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Coastal... a trip limit specified in this section taken in the EEZ may not be transferred at sea, regardless...

  18. Human round trip to Mars: Six months and radiation safe

    SciTech Connect

    Lazareth, O.W.; Schmidt, E.; Ludewig, H.; Powell, J.R.

    1991-01-01

    We describe a different type of round trip to Mars, using a combination of spacecraft. Compared to typical proposals, this flight is relatively fast and relatively safe from biological radiation dosage. Our study is concerned with the trip from Earth orbit to Mars orbit. Four spacecraft are required for the round trip. The crew spends most of their time on board a comparatively large, well shielded spacecraft (LC) which is in free (non-powered) orbit about the sun. The crew travels from Earth orbit to the LC while on board a comparatively small, powered spacecraft (SC). At Mars, the procedure is reversed and the crew returns on a second LC. In addition, a cargo craft, with no crew, is sent to Mars prior to the crew leaving Earth orbit. The trip time is about six months and the radiation dose equivalent is within guidelines recommended by the National Commission on Radiation Protection and Measurements.

  19. Rotation of a Thin Elastic Rod Injected into a Cylindrical Constraint

    NASA Astrophysics Data System (ADS)

    Mulcahy, Connor; Su, Tianxiang; Wicks, Nathan; Pabon, Jahir; Reis, Pedro

    2015-03-01

    We report the results from an experimental investigation of the buckling of a thin elastic rod injected into a horizontal cylindrical constraint, with an emphasis on comparing the two cases of rotating, or not, the rod at the injection site. We are particularly interested on the total length of rod that can be injected into the pipe prior to the onset of helical buckling. This instability arises due to the frictional rod-constraint contact that eventually leads to the buildup of axial stress on the rod, above a critical value. We explore the dependence of the buckling conditions on the physical and control parameters of the system (e.g. material and geometric parameters, injection speed and rotation frequency) and rationalize the underlying physical mechanism through a reduced model. Funding and support provided by Schlumberger-Doll Research.

  20. Controlled Assembly of Rod-Like Particles

    DTIC Science & Technology

    2012-11-29

    of Turnip Yellow Mosaic Virus by Cu(I) Catalyzed Azide?Alkyne 1,3-Dipolar Cycloaddition Reaction and Its Application in Cell Binding, Bioconjugate...that investigation of two-dimensional (2D) assembly of the icosahedral turnip yellow mosaic virus (TYMV) on cationic lipid monolayers at the air

  1. Observations on a Recent Trip to the Former Soviet Union

    DTIC Science & Technology

    1992-08-26

    NPS-NS-92-012 NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA AD-A255 891 J6 0- & R A D b OBSERVATIONS ON A RECENT TRIP TO THE FORMER SOVIET UNION BY...Include Security Classification) OBSERVATIONS ON A RECENT TRIP TO THE FORMER SOVIET UNION 12. PERSONAL AUTHOR(S) TRITTEN, JAMES JOHN 13a. TYPEOFREPORT...ABSTRACT (Continue on reverse if necessary and identify by block number) (8 A -C) ADDITIONAL SPONSOR, INTELLIGENCE PLANS & INTEGRATION DIRECTORATE

  2. Hypoxic preconditioning protects photoreceptors against light damage independently of hypoxia inducible transcription factors in rods.

    PubMed

    Kast, Brigitte; Schori, Christian; Grimm, Christian

    2016-05-01

    Hypoxic preconditioning protects photoreceptors against light-induced degeneration preserving retinal morphology and function. Although hypoxia inducible transcription factors 1 and 2 (HIF1, HIF2) are the main regulators of the hypoxic response, photoreceptor protection does not depend on HIF1 in rods. Here we used rod-specific Hif2a single and Hif1a;Hif2a double knockout mice to investigate the potential involvement of HIF2 in rods for protection after hypoxic preconditioning. To identify potential HIF2 target genes in rods we determined the retinal transcriptome of hypoxic control and rod-specific Hif2a knockouts by RNA sequencing. We show that rods do not need HIF2 for hypoxia-induced increased survival after light exposure. The transcriptomic analysis revealed a number of genes that are potentially regulated by HIF2 in rods; among those were Htra1, Timp3 and Hmox1, candidates that are interesting due to their connection to human degenerative diseases of the retina. We conclude that neither HIF1 nor HIF2 are required in photoreceptors for protection by hypoxic preconditioning. We hypothesize that HIF transcription factors may be needed in other cells to produce protective factors acting in a paracrine fashion on photoreceptor cells. Alternatively, hypoxic preconditioning induces a rod-intrinsic response that is independent of HIF transcription factors.

  3. Language Travel or Language Tourism: Have Educational Trips Changed So Much?

    ERIC Educational Resources Information Center

    Laborda, Jesus Garcia

    2007-01-01

    This article points out the changes in organization, students and language learning that language trips, as contrasted with educational trips (of which language trips are a subgroup) have gone through in the last years. The article emphasizes the need to differentiate between language trips and language tourism based on issues of additional…

  4. A Field Trip without Buses: Connecting Your Students to Scientists through a Virtual Visit

    ERIC Educational Resources Information Center

    Adedokun, Omolola; Parker, Loran Carleton; Loizzo, Jamie; Burgess, Wilella; Robinson, J. Paul

    2011-01-01

    One school offers zipTrips as an alternative to actual field trips taken outside of school. ZipTrips are web- and broadcast-delivered electronic field trips that include online videos, lesson plans, and a live, 45-minute interactive program consisting of four core components: an in-studio audience, live interaction with scientists, prerecorded…

  5. Managing the effect of TRIPS on availability of priority vaccines.

    PubMed Central

    Milstien, Julie; Kaddar, Miloud

    2006-01-01

    The stated purpose of intellectual property protection is to stimulate innovation. The Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) requires all Members of the World Trade Organization (WTO) to enact national laws conferring minimum standards of intellectual property protection by certain deadlines. Critics of the Agreement fear that such action is inconsistent with ensuring access to medicines in the developing world. A WHO convened meeting on intellectual property rights and vaccines in developing countries, on which this paper is based, found no evidence that TRIPS has stimulated innovation in developing market vaccine development (where markets are weak) or that protection of intellectual property rights has had a negative effect on access to vaccines. However, access to future vaccines in the developing world could be threatened by compliance with TRIPS. The management of such threats requires adherence of all countries to the Doha Declaration on TRIPS, and the protections guaranteed by the Agreement itself, vigilance on TRIPS-plus elements of free trade agreements, developing frameworks for licensing and technology transfer, and promoting innovative vaccine development in developing countries. The role of international organizations in defining best practices, dissemination of information, and monitoring TRIPS impact will be crucial to ensuring optimal access to priority new vaccines for the developing world. PMID:16710544

  6. Causal models of trip replanning in TravTek

    SciTech Connect

    Schryver, J.C.

    1998-07-01

    The TravTek operational field test was conducted to evaluate the effectiveness of route planning, route guidance and various navigational aiding modalities for Advanced Traveler Information Systems in ground vehicles. A causal network was constructed in order to achieve a better understanding of the dependencies among variables implicated in the replanning process. Causal inferences were modeled using path analysis techniques. The original Yoked Driver study reported that addition of real-time navigation planning did not increase trip efficiency during initial trip planning. Data mining of the relatively complete database revealed that the incidence of dynamic trip replanning was only 0.51% or 1 out of every 198 trips. Nevertheless, the replanning acceptance rate was 92.8%, suggesting that less conservative criteria might have been acceptable to drivers. Several points can be made based upon the path analysis techniques. Drivers who rejected better route offers were more likely to be male renters; rejected routes were apparently offered at earlier times with a lower predicted time savings and fewer maneuvers. Failure to accept a better route also apparently resulted in fewer wrong-turn deviations. Contrary to expectations, wrong-turn count and time loss appeared as semi-independent hubs in the resultant causal network. Implications of the path analysis are discussed. Proposals for in-vehicle information systems are formulated to increase driver participation as co-planner, and increase the likelihood that trip replanning will positively impact trip efficiency.

  7. Active Boundary Layer Trip for Supersonic Flows

    NASA Astrophysics Data System (ADS)

    Schloegel, F.; Panigua, G.; Tirtey, S.

    2009-01-01

    The last decade has been full of excitement and success for the hypersonic community thanks to various Scramjet ground tests and launches. These studies have shown promising potentials but the viability to perform commercial flights at Mach 8 is still to be demonstrated. An ideal Scramjet is one which is capable of self- starting over a wide range of angles of attack and Mach number. The Scramjet designer has to ensure that the boundary layer over the inlet ramp is fully turbulent where shocks impact, hence reducing the risks of chocked flow conditions. Most studies have issued the efficiency of roughness trip to trigger the boundary layer transition. At hypersonic speed, heat transfer and drag dramatically increase resulting in skin friction averaging at 40% of the overall drag. This study investigates the possibility of triggering transition using perpendicular air jets on a flat plate place in a hypersonic cross-flow. Experiments were conducted in the von Karman Institute hypersonic blow down wind tunnel H3. This facility is mounted with a Mach 6 contoured nozzles and provides flows with Reynolds number in the range of 10x106/m to 30x106/m. The model consist of a flat plate manufactured with a built -in settling chamber, equipped with a pressure tap and a thermocouple to monitor the jet conditions. A first flat plate was manufactured with a black-coated Plexiglas top, for surface heat transfer measurement using an infrared camera. On the second model, a Upilex sheet equipped with 32 thin film gages was glued, time dependent heat transfer measurements up to 60kHz. The jet injection conditions have been varied and a Mach number of 5.5 kept constant. The flow topology was investigated using fast schlieren techniques and oil flow, in order to gain a better understanding.

  8. Assessment of RELAP5/MOD2 against a main feedwater turbopump trip transient in the Vandellos II Nuclear Power Plant

    SciTech Connect

    Llopis, C.; Casals, A.; Perez, J.; Mendizabal, R.

    1993-12-01

    The Consejo de Seguridad Nuclear (CSN) and the Asociacion Nuclear Vandellos (ANV) have developed a model of Vandellos II Nuclear Power Plant. The ANV collaboration consisted in the supply of design and actual data, the cooperation in the simulation of the control systems and other model components, as well as in the results analysis. The obtained model has been assessed against the following transients occurred in plant: A trip from the 100% power level (CSN); a load rejection from 100% to 50% (CSN); a load rejection from 75% to 65% (ANV); and, a feedwater turbopump trip (ANV). This copy is a report of the feedwater turbopump trip transient simulation. This transient actually occurred in the plant on June 19, 1989.

  9. 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)

  10. 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…

  11. Modelling dynamic fronto-parietal behaviour during minimally invasive surgery--a Markovian trip distribution approach.

    PubMed

    Leff, Daniel Richard; Orihuela-Espina, Felipe; Leong, Julian; Darzi, Ara; Yang, Guang-Zhong

    2008-01-01

    Learning to perform Minimally Invasive Surgery (MIS) requires considerable attention, concentration and spatial ability. Theoretically, this leads to activation in executive control (prefrontal) and visuospatial (parietal) centres of the brain. A novel approach is presented in this paper for analysing the flow of fronto-parietal haemodynamic behaviour and the associated variability between subjects. Serially acquired functional Near Infrared Spectroscopy (fNIRS) data from fourteen laparoscopic novices at different stages of learning is projected into a low-dimensional 'geospace', where sequentially acquired data is mapped to different locations. A trip distribution matrix based on consecutive directed trips between locations in the geospace reveals confluent fronto-parietal haemodynamic changes and a gravity model is applied to populate this matrix. To model global convergence in haemodynamic behaviour, a Markov chain is constructed and by comparing sequential haemodynamic distributions to the Markov's stationary distribution, inter-subject variability in learning an MIS task can be identified.

  12. 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.

  13. 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.

  14. Fundamental study of the austenite formation and decomposition in low-silicon, aluminum added TRIP steels

    NASA Astrophysics Data System (ADS)

    Garcia-Gonzalez, Jose Enrique

    2005-11-01

    TRIP (Transformation Induced Plasticity) steels are under development for automotive applications that require high strength and excellent formability. Conventional TRIP steels consist of a multiphase microstructure comprised of a ferrite matrix with a dispersion of bainite and metastable retained austenite. The high ductility exhibited by these steels results from the transformation of the metastable retained austenite to martensite during straining. In conventional TRIP steel processing, the multiphase microstructure is obtained by controlled cooling from the alpha + gamma region to an isothermal holding temperature. During this holding, bainite forms and carbon is rejected out into the austenite, which lowers the Ms temperature and stabilizes the austenite to room temperature. In this research project, a fundamental study of a low-Si, Mo-Nb added cold rolled TRIP steel with and without Al additions was conducted. In this study, the recrystallization of cold-rolled ferrite, the formation of austenite during intercritical annealing and the characteristics of the decomposition of the intercritically annealed austenite by controlled cooling rates were systematically assessed. Of special interest were: (i) the effect of the initial hot band microstructure, (ii) the formation of epitaxial ferrite during cooling from the intercritical annealing temperature to the isothermal holding temperature, (iii) the influence of the intercritically annealed austenite on the formation of bainite during the isothermal holding temperature, and (iv) the influence of the processing variables on the type, amount, composition and stability of the retained austenite. During this research study, techniques such as OM, SEM, EBSD, TEM, XRD and Magnetometry were used to fully characterize the microstructures. Furthermore, a Gleeble 3500 unit at US Steel Laboratories was used for dilatometry studies and to simulate different CGL processing routes, from which specimens were obtained to evaluate

  15. 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

  16. 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

  17. Parallel Operation of Multiple Closely Spaced Small Aspect Ratio Rod Pinches

    DOE PAGES

    Harper-Slaboszewicz, Victor J.; Leckbee, Joshua; Bennett, Nichelle; ...

    2014-12-10

    A series of simulations and experiments to resolve questions about the operation of arrays of closely spaced small aspect ratio rod pinches has been performed. Design and post-shot analysis of the experimental results are supported by 3D particle-in-cell simulations. Both simulations and experiments support these conclusions. Penetration of current to the interior of the array appears to be efficient, as the current on the center rods is essentially equal to the current on the outer rods. Current loss in the feed due to the formation of magnetic nulls was avoided in these experiments by design of the feed surface ofmore » the cathode and control of the gap to keep the electric fields on the cathode below the emission threshold. Some asymmetry in the electron flow to the rod was observed, but the flow appeared to symmetrize as it reached the end of the rod. Interaction between the rod pinches can be controlled to allow the stable and consistent operation of arrays of rod pinches.« less

  18. Parallel Operation of Multiple Closely Spaced Small Aspect Ratio Rod Pinches

    SciTech Connect

    Harper-Slaboszewicz, Victor J.; Leckbee, Joshua; Bennett, Nichelle; Madrid, Elizabeth A.; Rose, David V.; Thoma, Carsten; Welch, Dale R.; Lake, Patrick W.; McCourt, Andrew L.

    2014-12-10

    A series of simulations and experiments to resolve questions about the operation of arrays of closely spaced small aspect ratio rod pinches has been performed. Design and post-shot analysis of the experimental results are supported by 3D particle-in-cell simulations. Both simulations and experiments support these conclusions. Penetration of current to the interior of the array appears to be efficient, as the current on the center rods is essentially equal to the current on the outer rods. Current loss in the feed due to the formation of magnetic nulls was avoided in these experiments by design of the feed surface of the cathode and control of the gap to keep the electric fields on the cathode below the emission threshold. Some asymmetry in the electron flow to the rod was observed, but the flow appeared to symmetrize as it reached the end of the rod. Interaction between the rod pinches can be controlled to allow the stable and consistent operation of arrays of rod pinches.

  19. Field Trips and Their Effect on Student Achievement and Attitudes: A Comparison of Physical versus Virtual Field Trips to the Indian River Lagoon

    ERIC Educational Resources Information Center

    Garner, Lesley C.; Gallo, Michael A.

    2005-01-01

    This study examined the effect of physical and virtual field trips on undergraduate, nonscience majors. No significant differences were seen in achievement, attitudes, learning styles, interactions between field trip and learning styles, or students' ability to answer questions at different levels. Results imply that both field trips promote…

  20. 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.

  1. 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.

  2. 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.

  3. Appraisal of boundary layer trips for landing gear testing

    NASA Astrophysics Data System (ADS)

    McCarthy, Philip; Feltham, Graham; Ekmekci, Alis

    2013-11-01

    Dynamic similarity during scaled model testing is difficult to maintain. Forced boundary layer transition via a surface protuberance is a common method used to address this issue, however few guidelines exist for the effective tripping of complex geometries, such as aircraft landing gears. To address this shortcoming, preliminary wind tunnel tests were performed at Re = 500,000. Surface transition visualisation and pressure measurements show that zigzag type trips of a given size and location are effective at promoting transition, thus preventing the formation of laminar separation bubbles and increasing the effective Reynolds number from the critical regime to the supercritical regime. Extension of these experiments to include three additional tripping methods (wires, roughness strips, CADCUT dots) in a range of sizes, at Reynolds number of 200,000 and below, have been performed in a recirculating water channel. Analysis of surface pressure measurements and time resolved PIV for each trip device, size and location has established a set of recommendations for successful use of tripping for future, low Reynolds number landing gear testing.

  4. Evidence, explanations, and recommendations for teachers' field trip strategies

    NASA Astrophysics Data System (ADS)

    Rebar, Bryan

    Field trips are well recognized by researchers as an educational approach with the potential to complement and enhance classroom science teaching by exposing students to unique activities, resources, and content in informal settings. The following investigation addresses teachers' field trip practices in three related manuscripts: (1) A study examining the details of teachers' pedagogical strategies intended to facilitate connections between students' experiences and the school curricula while visiting an aquarium; (2) A study documenting and describing sources of knowledge that teachers draw from when leading field trips to an aquarium; (3) A position paper that reviews and summarizes research on effective pedagogical strategies for field trips. Together these three pieces address key questions regarding teachers' practices on field trips: (1) What strategies are teachers employing (and not employing) during self-guided field trips to facilitate learning tied to the class curriculum? (2) What sources of knowledge do teachers utilize when leading field trips? (3) How can teachers be better prepared to lead trips that promote learning? The Oregon Coast Aquarium served as the field trip site for teachers included in this study. The setting suited these questions because the aquarium serves tens of thousands of students on field trips each year but provides no targeted programming for these students as they explore the exhibits. In other words, the teachers who lead field trips assume much of the responsibility for facilitating students' experience. In order to describe and characterize teachers' strategies to link students' experiences to the curriculum, a number of teachers (26) were observed as they led their students' visit to the public spaces of the aquarium. Artifacts, such as worksheets, used during the visit were collected for analysis as well. Subsequently, all teachers were surveyed regarding their use of the field trip and their sources of knowledge for

  5. 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

  6. 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.

  7. Thermoreversible Gels Composed of Colloidal Silica Rods with Short-Range Attractions

    DOE PAGES

    Murphy, Ryan P.; Hong, Kunlun; Wagner, Norman J.

    2016-07-28

    Dynamic arrest transitions of colloidal suspensions containing non-spherical particles are of interest for the design and processing of various particle technologies. To better understand the effects of particle shape anisotropy and attraction strength on gel and glass formation, we present a colloidal model system of octadecyl-coated silica rods, termed as adhesive hard rods (AHR), which enables control of rod aspect ratio and temperature-dependent interactions. The aspect ratios of silica rods were controlled by varying the initial TEOS concentration following the work of Kuijk et al. (J. Am. Chem. Soc., 2011, 133, 2346–2349) and temperature-dependent attractions were introduced by coating themore » calcined silica rods with an octadecyl-brush and suspending in tetradecane. The rod length and aspect ratio were found to increase with TEOS concentration as expected, while other properties such as the rod diameter, coating coverage, density, and surface roughness were nearly independent of the aspect ratio. Ultra-small angle X-ray scattering measurements revealed temperature-dependent attractions between octadecyl-coated silica rods in tetradecane, as characterized by a low-q upturn in the scattered intensity upon thermal quenching. Lastly, the rheology of a concentrated AHR suspension in tetradecane demonstrated thermoreversible gelation behavior, displaying a nearly 5 orders of magnitude change in the dynamic moduli as the temperature was cycled between 15 and 40 °C. We find the adhesive hard rod model system serves as a tunable platform to explore the combined influence of particle shape anisotropy and attraction strength on the dynamic arrest transitions in colloidal suspensions with thermoreversible, short-range attractions.« less

  8. Thermoreversible Gels Composed of Colloidal Silica Rods with Short-Range Attractions

    SciTech Connect

    Murphy, Ryan P.; Hong, Kunlun; Wagner, Norman J.

    2016-07-28

    Dynamic arrest transitions of colloidal suspensions containing non-spherical particles are of interest for the design and processing of various particle technologies. To better understand the effects of particle shape anisotropy and attraction strength on gel and glass formation, we present a colloidal model system of octadecyl-coated silica rods, termed as adhesive hard rods (AHR), which enables control of rod aspect ratio and temperature-dependent interactions. The aspect ratios of silica rods were controlled by varying the initial TEOS concentration following the work of Kuijk et al. (J. Am. Chem. Soc., 2011, 133, 2346–2349) and temperature-dependent attractions were introduced by coating the calcined silica rods with an octadecyl-brush and suspending in tetradecane. The rod length and aspect ratio were found to increase with TEOS concentration as expected, while other properties such as the rod diameter, coating coverage, density, and surface roughness were nearly independent of the aspect ratio. Ultra-small angle X-ray scattering measurements revealed temperature-dependent attractions between octadecyl-coated silica rods in tetradecane, as characterized by a low-q upturn in the scattered intensity upon thermal quenching. Lastly, the rheology of a concentrated AHR suspension in tetradecane demonstrated thermoreversible gelation behavior, displaying a nearly 5 orders of magnitude change in the dynamic moduli as the temperature was cycled between 15 and 40 °C. We find the adhesive hard rod model system serves as a tunable platform to explore the combined influence of particle shape anisotropy and attraction strength on the dynamic arrest transitions in colloidal suspensions with thermoreversible, short-range attractions.

  9. 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

  10. Principles of TRIP Steel Optimization for Passive Damping Applications

    NASA Astrophysics Data System (ADS)

    Fraley, George Jay

    Globally many historic structures of cultural significance which do not have systems to mitigate seismic damage are located in areas with heavy seismic activity. Efforts have been undertaken to develop strategies to retrofit such structures, however any intervention must be limited in size for aesthetic reasons. To contribute to this effort, ArcelorMittal aims to create steel-based solutions for passive energy dissipation through plastic deformation during cyclic loading. High-strength TRansformation-Induced Plasticity (TRIP) steels are proposed as an excellent candidate material for this application, due to the extreme combination of high strength and large ductility they are well-known to exhibit. To evaluate high-strength TRIP steels for passive damping applications, isothermal, fully-reversed, displacement-controlled Ultra-Low Cycle Fatigue (ULCF) experiments (Nf < 100) were conducted on two tempering conditions of austenitic BlastAlloy (BA) TRIP 180. One tempering condition resulted in a Mssigma temperature of 27 °C and stress-assisted martensitic nucleation, and the other a Mssigma temperature of -8 °C and strain-induced martensitic nucleation at room temperature. The higher austenite stability condition (Ms sigma = -8 °C) was found to have approximately twice the fatigue life and a lower rate of cyclic hardening at fixed displacement amplitudes for low to intermediate levels of plastic strain range (2-10%) compared to the lower stability austenite condition (Mssigma = 27 °C). However, at higher levels of plastic straining (10-16% strain range) the fatigue lives and strain hardening behavior converged for the two stabilities, indicating a likely exhaustion of transformation during the first few cycles. ULCF life behavior for the high-stability austenite condition compared favorably with literature values for structural stainless steel 316, despite having a yield strength approximately four times larger. For a similar number of cycles to failure the high

  11. Hypersonic Boundary-Layer Trip Development for Hyper-X

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; Auslender, Aaron H.; Dilley, Authur D.; Calleja, John F.

    2000-01-01

    Boundary layer trip devices for the Hper-X forebody have been experimentally examined in several wind tunnels. Five different trip configurations were compared in three hypersonic facilities, the LaRC 20-Inch Mach 6 Air Tunnel, the LaRC 31 -Inch Mach 10 Air Tunnel, and in the HYPULSE Reflected Shock Tunnel at GASL. Heat transfer distributions, utilizing the phosphor thermography and thin-film techniques, shock system details, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles-of-attack of 0-deg, 2-deg, and 4-deg; Reynolds numbers based on model length of 1.2 to 15.4 million: and inlet cowl door simulated in both open and closed positions. Comparisons of transition due to discrete roughness elements have led to the selection of a trip configuration for the Hyper-X Mach 7 flight vehicle.

  12. Mechanical and Microstructural Characterization of an Aluminum Bearing Trip Steel

    NASA Astrophysics Data System (ADS)

    Monsalve, Alberto; Guzmán, Alexis; De Barbieri, Flavio; Artigas, Alfredo; Carvajal, Linton; Bustos, Oscar; Garza-Montes-de Oca, Nelson F.; Colás, Rafael

    2016-06-01

    The mechanical properties and microstructural characteristics of a steel able to sustain the TRIP-effect were studied. The material was prepared by taking in mind the partial substitution of silicon by aluminum following a processing route that included hot forging, hot and cold rolling, intercritical annealing, and a final bainitic isothermal treatment. The mechanical properties that were obtained resulted to be above those of commercial a 780 TRIP steel. The TRIP phenomenon was confirmed by the change in retained austenite before and after deforming the steel; X-ray diffraction was used to evaluate the volume content of retained austenite. Formability of the steel under study can be rationalized in terms of the texture developed in the material.

  13. Texture developed during deformation of Transformation Induced Plasticity (TRIP) steels

    NASA Astrophysics Data System (ADS)

    Bhargava, M.; Shanta, C.; Asim, T.; Sushil, M.

    2015-04-01

    Automotive industry is currently focusing on using advanced high strength steels (AHSS) due to its high strength and formability for closure applications. Transformation Induced Plasticity (TRIP) steel is promising material for this application among other AHSS. The present work is focused on the microstructure development during deformation of TRIP steel sheets. To mimic complex strain path condition during forming of automotive body, Limit Dome Height (LDH) tests were conducted and samples were deformed in servo hydraulic press to find the different strain path. FEM Simulations were done to predict different strain path diagrams and compared with experimental results. There is a significant difference between experimental and simulation results as the existing material models are not applicable for TRIP steels. Micro texture studies were performed on the samples using EBSD and X-RD techniques. It was observed that austenite is transformed to martensite and texture developed during deformation had strong impact on limit strain and strain path.

  14. Field trips in the southern Rocky Mountains, USA

    SciTech Connect

    Nelson, E.P.; Erslev, E.A.

    2004-07-01

    The theme of the 2004 GSA Annual Meeting and Exposition, 'Geoscience in a Changing World' covers both new and traditional areas of the earth sciences. The Front Range of the Rocky Mountains and the High Plains preserve an outstanding record of geological processes from Precambrian through Quaternary times, and thus served as excellent educational exhibits for the meeting. The chapters in this field guide all contain technical content as well as a field trip log describing field trip routes and stops. Of the 25 field trips offered at the Meeting. 14 are described in the guidebook, covering a wide variety of geoscience disciplines, with chapters on tectonics (Precambrian and Laramide), stratigraphy and paleoenvironments (e.g., early Paleozoic environments, Jurassic eolian environments, the K-T boundary, the famous Oligocene Florissant fossil beds), economic deposits (coal and molybdenum), geological hazards, and geoarchaeology. Two papers have been abstracted separately for the Coal Abstracts database.

  15. Leg vein hemodynamics during bedrests simulating lunar trip.

    PubMed

    Louisy, F; Guezennec, C Y; Güell, A

    1994-05-01

    When contemplating future trips to the Moon whose gravity is one sixth of Earth gravity, the question is to know what the adaptive changes in the lower limb venous system would be. In fact, one can suppose that the presence of a partial gravity on the Moon would be able to attenuate venous hemodynamics adaptative changes observed in microgravity. In the present experiment changes in the venous hemodynamics of lower limbs have been studied with mercury strain gauge plethysmography during a simulated Moon mission including a 4 day trip to the Moon (-6 degrees bedrest), a stay of 6 days on the Moon (+11 degrees bedrest), and a 4-day trip back to Earth (-6 degrees bedrest). It was previously demonstrated that +11 degrees bedrest was a good model to simulate the effects of lunar gravity on the cardiovascular system (Vernikos-Danellis J 1986, personnal communication).

  16. 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.

  17. TRIP: General computer algebra system for celestial mechanics

    NASA Astrophysics Data System (ADS)

    Laskar, J.; Gastineau, M.

    2012-10-01

    TRIP is an interactive computer algebra system that is devoted to perturbation series computations, and specially adapted to celestial mechanics. Its development started in 1988, as an upgrade of the special purpose FORTRAN routines elaborated by J. Laskar for the demonstration of the chaotic behavior of the Solar System. TRIP is a mature and efficient tool for handling multivariate generalized power series, and embeds two kernels, a symbolic and a numerical kernel. This numerical kernel communicates with Gnuplot or Grace to plot the graphics and allows one to plot the numerical evaluation of symbolic objects.

  18. Bad trip due to anticholinergic effect of cannabis.

    PubMed

    Mangot, Ajish G

    2013-01-01

    Cannabis in its various forms has been known since time immemorial, the use of which has been rising steadily in India. 'Bad trips' have been documented after cannabis use, manifestations ranging from vague anxiety and fear to profoundly disturbing states of terror and psychosis. Cannabis is known to affect various neurotransmitters, but 'bad trip' due to its anticholinergic effect has never been described in literature to the best of author's knowledge. Hereby, the author describes a case of a young adult male experiencing profound anticholinergic effects after being exposed for the first time in his life to bhang, a local oral preparation of cannabis.

  19. 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.

  20. 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

  1. 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.

  2. Interaction of Fixed Number of Photons with Retinal Rod Cells

    NASA Astrophysics Data System (ADS)

    Phan, Nam Mai; Cheng, Mei Fun; Bessarab, Dmitri A.; Krivitsky, Leonid A.

    2014-05-01

    New tools and approaches of quantum optics offer a unique opportunity to generate light pulses carrying a precise number of photons. Accurate control over the light pulses helps to improve the characterization of photoinduced processes. Here, we study interaction of a specialized light source which provides flashes containing just one photon, with retinal rod cells of Xenopus laevis toads. We provide unambiguous proof of the single-photon sensitivity of rod cells without relying on the statistical modeling. We determine their quantum efficiencies without the use of any precalibrated detectors and obtain the value of (29±4.7)%. Our approach provides the path for future studies and applications of quantum properties of light in phototransduction, vision, and photosynthesis.

  3. 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

  4. 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.

  5. 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.

  6. CONTROL SYSTEM FOR NEUTRONIC REACTORS

    DOEpatents

    Crever, F.E.

    1962-05-01

    BS>A slow-acting shim rod for control of major variations in reactor neutron flux and a fast-acting control rod to correct minor flux variations are employed to provide a sensitive, accurate control system. The fast-acting rod is responsive to an error signal which is produced by changes in the neutron flux from a predetermined optimum level. When the fast rod is thus actuated in a given direction, means is provided to actuate the slow-moving rod in that direction to return the fast rod to a position near the midpoint of its control range. (AEC)

  7. CONTROL FOR NEUTRONIC REACTOR

    DOEpatents

    Lichtenberger, H.V.; Cameron, R.A.

    1959-03-31

    S>A control rod operating device in a nuclear reactor of the type in which the control rod is gradually withdrawn from the reactor to a position desired during stable operation is described. The apparatus is comprised essentially of a stop member movable in the direction of withdrawal of the control rod, a follower on the control rod engageable with the stop and means urging the follower against the stop in the direction of withdrawal. A means responsive to disengagement of the follower from the stop is provided for actuating the control rod to return to the reactor shut-down position.

  8. 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.

  9. 50 CFR 622.44 - Commercial trip limits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Caribbean EEZ more than 150 queen conch per day. (f) Atlantic dolphin and wahoo. (1) The trip limit for... Federal commercial permit for Atlantic dolphin and wahoo, provided that the vessel is not operating as a... permit for Atlantic dolphin and wahoo but has a Federal commercial vessel permit in any other fishery...

  10. 50 CFR 622.278 - Commercial trip limits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and... limits on the amount of Atlantic dolphin and wahoo that may be possessed on board or landed, purchased...) Atlantic dolphin and wahoo. (1) The trip limit for wahoo in or from the Atlantic EEZ is 500 lb (227...

  11. 50 CFR 622.278 - Commercial trip limits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and... limits on the amount of Atlantic dolphin and wahoo that may be possessed on board or landed, purchased...) Atlantic dolphin and wahoo. (1) The trip limit for wahoo in or from the Atlantic EEZ is 500 lb (227...

  12. Planning a Class Camping Trip. ERIC Digest: Outdoor Education.

    ERIC Educational Resources Information Center

    Little, Mickey; Peterson, Lin

    A well-planned class camping trip is a learning adventure which develops personal values, generates lifelong learning skills, encourages group cooperation, and enhances knowledge of and appreciation for natural environments. This digest is a guide to help teachers offer this unique learning opportunity to their students. Separate sections present…

  13. Journal of South African Trip: January 14-March 1, 1986.

    ERIC Educational Resources Information Center

    Rogers, Carl R.

    1987-01-01

    Provides a personal account, dictated en route, of Carl Rogers' experiences during his trip to South Africa. Documents extensive commitment to people and to a process leading to peace. Journal ends with conviction that violence can be avoided and that no group really wants violence. (Author)

  14. Cognitive Impact of a Grade School Field Trip.

    ERIC Educational Resources Information Center

    Morrell, Patricia D.

    2003-01-01

    Presents a study to design and conduct a three-hour field experience for 3rd and 4th grade students on forestry and forest products, and to determine the cognitive effects of participation in this field trip on the children. Reports an increase in student knowledge after participating in this experience. Discusses the reasons for students'…

  15. Un Viaje al Aeropuerto (A Trip to the Airport).

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC.

    This illustrated, bilingual Spanish-English intermediate reader describes a class trip to an airport, in which the class tours the airport, and learns about airport activities, the parts of an airplane, and other related topics. Each page of the text is illustrated with a drawing. The narrative is followed by a list of 24 suggested learning…

  16. Examining the Effects of Field Trips on Science Identity

    ERIC Educational Resources Information Center

    Mills, Leila A.; Katzman, William

    2015-01-01

    The purpose of this work-in-progress study is to examine science identity of elementary school students in relation to participation in science. The questions asked in this initial analysis were: How will a field trip to a science research and learning center affect students' desires to learn and participate in science and does interviewing…

  17. Trip Staff Training Practices: Survey and Discussion Results.

    ERIC Educational Resources Information Center

    Zwaagstra, Lynn

    A discussion group and survey examined trip-staff training practices among outdoor and adventure recreation/education programs. Of the 40 participants, 80 percent worked with university noncredit programs, with the remaining participants representing university for-credit, military recreation, nonprofit, and for-profit programs. Although the…

  18. Field Trips as Teaching Tools in the Law Curriculum

    ERIC Educational Resources Information Center

    Higgins, Noelle; Dewhurst, Elaine; Watkins, Los

    2012-01-01

    While field trips are often employed in primary and even second level education as a pedagogical tool, aimed at exposing students to real life experiences, such activities are not as popular at third level (Falk and Balling, 1982; Muse, Chiarelott and Davidman, 1982; Anderson and Zhang, 2003). However, such experiential learning techniques can be…

  19. Using a National Park for a Field Trip

    ERIC Educational Resources Information Center

    Baer, Roy K.

    1977-01-01

    Describes a one-week camping trip to Acadia National Park (Maine) as a non-credit educational experience. Includes activities such as population studies in intertidal zones, wild life sketching, nature list hikes (forest devastation by fire, beaver ponds, glacial ponds and streams), fishing and clamming rips, and student projects. (CS)

  20. A Classical Mnemonic for Older Learners: A Trip That Works

    ERIC Educational Resources Information Center

    Robertson-Tchabo, Elizabeth A.; And Others

    1976-01-01

    A mnemonic procedure, a method of loci, was used with men and women over 60 years old in two studies of free recall. The learners take a mental trip through their residences stopping in order at 16 places. Experimental subjects were able to master the mnemonic and apply it effectively. (Author)

  1. The Goat Portage: Students' Stories and Learning from Canoe Trips.

    ERIC Educational Resources Information Center

    Horwood, Bert

    This study explores how high school students learn from their experiences in an extracurricular adventure program and illustrates how students' narrative inquiries relate to experiential learning. Twelve canoe trips were studied by participant observation methods. Data were collected from recorded interviews with students and staff, field notes,…

  2. 50 CFR 622.495 - Commercial trip limit.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Queen Conch... trip limit specified in this section taken in the EEZ may not be transferred at sea, regardless of... conch in or from the Caribbean EEZ is 200 queen conch per day....

  3. Tape the Teacher: Easier Field Trips for Large Classes

    ERIC Educational Resources Information Center

    Carter, Lynne; And Others

    1974-01-01

    Describes a tape-guided field trip that has been used successfully with college biology students in the University of California Botanical Garden. This program enables large numbers of students to make individual biological observations in the field with the aid of a specially tailored, taped guide. (JR)

  4. 50 CFR 622.385 - Commercial trip limits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... a trip limit specified in this section taken in the EEZ may not be transferred at sea, regardless of...., which is a line directly east from the Flagler/Volusia County, FL, boundary, king mackerel in or from... east from the Volusia/Brevard County, FL, boundary, king mackerel in or from the EEZ may not...

  5. Computer simulation of equilibrium conditions following a plant 'trip'

    NASA Astrophysics Data System (ADS)

    Limb, D.

    When a process or part of a process experiences an emergency 'trip', the contained fluids redistribute themselves based upon the prevailing pressure gradients and depending upon the positions of valves at the time of the trip. Reverse flow through rotating compression machinery may occur, depending upon the locations of non-return valves. Reduction in pressure and mixing of cryogenic fluids of different compositions and/or temperatures can both lead to generation of significant volumes of vapour. This equilibration process is usually largely over in a matter of seconds rather than minutes. Key questions facing process and mechanical designers are: what is the settle-out pressure, and can we ensure relief valves do not lift following a trip? To answer these related questions it is necessary to analyse the state of the system prior to the trip, and then, based upon valve positions, etc., construct a model of the worst case probable scenarios for the qualitative redistribution of fluid inventory. At this point the simulation program may be employed to help calculate rigorously the final settle out conditions for each of the possible scenarios. This technique is particularly appropriate for cryogenic processes including refrigeration cycles. It is illustrated here with the help of a multistage hydrocarbon compressor example. Other related non-standard applications of the steady state process simulation program are identified.

  6. Self-Guided Field Trips for Students of Environments

    ERIC Educational Resources Information Center

    Moore, G.; Kerr, Roger; Hadgraft, Roger

    2011-01-01

    In many learning institutions around the world, there is a trend towards larger classes, more flexible learning pathways and reduced teaching resources. Experiential learning is often used in the form of site visits or field trips for students studying engineering, natural resource management, geography and similar disciplines. Providing…

  7. A Trip to Historic Philadelphia on the Web.

    ERIC Educational Resources Information Center

    Wilson, Elizabeth K.

    1997-01-01

    Describes an electronic field trip to colonial Philadelphia (Pennsylvania). The historic locale has generated enough websites (Philadelphia Historic District, Betsy Ross homepage, and the Franklin Institute Science Museum) for students to take a virtual tour of the colonial capital. Suggests structuring the activity as a know-want-learn (KWL)…

  8. The Field Trip Book: Study Travel Experiences in Social Studies

    ERIC Educational Resources Information Center

    Morris, Ronald V.

    2010-01-01

    Looking for social studies adventures to help students find connections to democratic citizenship? Look no further! This book provides just the answer teachers need for engaging students in field trips as researching learners with emphasis on interdisciplinary social studies plus skills in collecting and reporting data gathered from field…

  9. Trip Reports. Hazardous Waste Minimization and Control at Army Depots

    DTIC Science & Technology

    1989-08-01

    phosphoric acid and sludge from the bottom of the tank is a very small waste stream at Tobyhanna; therefore, even complete elimination of this *waste... stream would result in only a small reduction in hazardous waste generation. Tooele performed several tests with Rust Eliminator on a variety of...rinse waters are treated In the Industrial Waste Treatment Plant (lWTW.. However, this stream is not monitored for Total Toxic Organics. The cleaning ae

  10. Goldschmidt Conference 2005: Field Trip Guide to the Columbia River Basalt Group

    SciTech Connect

    Martin, Barton S.; Petcovic, Heather L.; Reidel, Steve P.

    2005-06-16

    This field trip guide was prepared for the 2005 Goldschmidt Conference held in Moscow, Idaho. The field trip guide provides a two day introduction to the features of the Columbia River Basalt Group in eastern Washington.

  11. Bacterial Flagella as a Model Rigid Rod of Tunable Shape

    NASA Astrophysics Data System (ADS)

    Schwenger, Walter; Yardimci, Sevim; Gibaud, Thomas; Snow, Henry; Urbach, Jeff; Dogic, Zvonimir

    In this research, we study the physical properties of suspensions of bacterial flagella from Salmonella typhimurium prepared in a variety of rigid polymorphic shapes. Flagella act as a rigid colloidal particle that can exhibit non-trivial geometry including helices of varying dimensions, straight rods, or a combination of the two in the same filament. By controlling the conditions in which flagella are prepared, the polymorphic shape assumed by the filament can be controlled. Utilizing different polymorphic shapes, we combine results from optical microscopy observations of single filaments with bulk rheological measurements to help understand the role that constituent colloidal geometry plays in complex bulk behavior.

  12. 78 FR 10556 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; Trip Limit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-14

    ... Handgear B (HB) trip limit for GOM and GB cod be adjusted proportionally (rounded up to the nearest 25 lb..., due to a reduced GOM cod sub-ACL for the common pool. Ultimately, the HB trip limit for GOM cod is... A DAS vessels, the new GOM cod trip limit for HB vessels is 200 lb (90.7 kg) per trip (75 lb...

  13. NEURONATIN IS A STRESS-RESPONSIVE PROTEIN OF ROD PHOTORECEPTORS

    PubMed Central

    SHINDE, VISHAL; PITALE, PRIYAMVADA M.; HOWSE, WAYNE; GORBATYUK, OLEG; GORBATYUK, MARINA

    2016-01-01

    Neuronatin (NNAT) is a small transmembrane proteolipid that is highly expressed in the embryonic developing brain and several other peripheral tissues. This study is the first to provide evidence that NNAT is detected in the adult retina of various adult rod-dominant mammals, including wild-type (WT) rodents, transgenic rodents expressing mutant S334ter, P23H, or T17M rhodopsin, non-human primates, humans, and cone-dominant tree shrews. Immunohistochemical and quantitative real time polymerase chain reaction (qRT-PCR) analyses were applied to detect NNAT. Confocal microscopy analysis revealed that NNAT immunofluorescence is restricted to the outer segments (OSs) of photoreceptors without evidence of staining in other retinal cell types across all mammalian species. Moreover, in tree shrew retinas, we found NNAT to be co-localized with rhodopsin, indicating its predominant expression in rods. The rod-derived expression of NNAT was further confirmed by qRT-PCR in isolated rod photoreceptor cells. We also used these cells to mimic cellular stress in transgenic retinas by treating them with the endoplasmic reticulum stress inducer, tunicamycin. Thus, our data revealed accumulation of NNAT around the nucleus as compared to dispersed localization of NNAT within control cells. This distribution coincided with the partial intracellular mislocalization of NNAT to the outer nuclear layer observed in transgenic retinas. In addition, stressed retinas demonstrated an increase of NNAT mRNA and protein levels. Therefore, our study demonstrated that NNAT is a novel stress-responsive protein with a potential structural and/or functional role in adult mammalian retinas. PMID:27109921

  14. Development of burnup dependent fuel rod model in COBRA-TF

    NASA Astrophysics Data System (ADS)

    Yilmaz, Mine Ozdemir

    predictions. After confirming that the new fuel thermal conductivity model in CTF worked and provided consistent results with FRAPTRAN predictions for a single fuel rod configuration, the same type of analysis was carried out for a bigger system which is the 4x4 PWR bundle consisting of 15 fuel pins and one control guide tube. Steady- state calculations at Hot Full Power (HFP) conditions for control guide tube out (unrodded) were performed using the 4x4 PWR array with CTF/TORT-TD coupled code system. Fuel centerline, surface and average temperatures predicted by CTF/TORT-TD with and without the new fuel thermal conductivity model were compared against CTF/TORT-TD/FRAPTRAN predictions to demonstrate the improvement in fuel centerline predictions when new model was used. In addition to that constant and CTF dynamic gap conductance model were used with the new thermal conductivity model to show the performance of the CTF dynamic gap conductance model and its impact on fuel centerline and surface temperatures. Finally, a Rod Ejection Accident (REA) scenario using the same 4x4 PWR array was run both at Hot Zero Power (HZP) and Hot Full Power (HFP) condition, starting at a position where half of the control rod is inserted. This scenario was run using CTF/TORT-TD coupled code system with and without the new fuel thermal conductivity model. The purpose of this transient analysis was to show the impact of thermal conductivity degradation (TCD) on feedback effects, specifically Doppler Reactivity Coefficient (DRC) and, eventually, total core reactivity.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. The Practice of Prospective Science Teachers regarding the Planning of Education Based Trips: Evaluation of Six Different Field Trips

    ERIC Educational Resources Information Center

    Bozdogan, Aykut Emre

    2012-01-01

    The aim of this study is to explain how planning educational trips out of school environments for training purposes should be as well as to determine the opinions and the practices of prospective science teachers. The study that lasted for two years was carried out in parallel with the elective course "Science Education in Informal Learning…

  20. Questionnaire-based person trip visualization and its integration to quantitative measurements in Myanmar

    NASA Astrophysics Data System (ADS)

    Kimijiama, S.; Nagai, M.

    2016-06-01

    With telecommunication development in Myanmar, person trip survey is supposed to shift from conversational questionnaire to GPS survey. Integration of both historical questionnaire data to GPS survey and visualizing them are very important to evaluate chronological trip changes with socio-economic and environmental events. The objectives of this paper are to: (a) visualize questionnaire-based person trip data, (b) compare the errors between questionnaire and GPS data sets with respect to sex and age and (c) assess the trip behaviour in time-series. Totally, 345 individual respondents were selected through random stratification to assess person trip using a questionnaire and GPS survey for each. Conversion of trip information such as a destination from the questionnaires was conducted by using GIS. The results show that errors between the two data sets in the number of trips, total trip distance and total trip duration are 25.5%, 33.2% and 37.2%, respectively. The smaller errors are found among working-age females mainly employed with the project-related activities generated by foreign investment. The trip distant was yearly increased. The study concluded that visualization of questionnaire-based person trip data and integrating them to current quantitative measurements are very useful to explore historical trip changes and understand impacts from socio-economic events.

  1. Africana Acquisitions; Report of a Publication Survey Trip to Nigeria, Southern Africa, and Europe, 1972.

    ERIC Educational Resources Information Center

    Witherell, Julian W.

    A publication survey trip to Nigeria, Southern Africa, and Europe was taken by Julian W. Witherell of the African Section of the Library of Congress in 1972. The purpose of the trip was to improve the flow of publications about Africa to the Library of Congress. The trip was successful in that personal contacts helpful in obtaining local materials…

  2. Guide to Canoe Camping. A Comprehensive Planning Guide for Canoe Trip Leaders.

    ERIC Educational Resources Information Center

    Johnstone, D. Bruce

    A canoe camping trip offers an exciting, inexpensive vacation from the usual daily routine and environment, and develops resourcefulness, cooperation, and camaraderie among participants. Chapter 1 of this guide discusses preliminary planning of a canoe trip, including decisions on the length and type of trip, designation of a leader for large…

  3. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a...

  4. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a...

  5. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a...

  6. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a...

  7. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a...

  8. Echoes from the Field: An Ethnographic Investigation of Outdoor Science Field Trips

    ERIC Educational Resources Information Center

    Boxerman, Jonathan Zvi

    2013-01-01

    As popular as field trips are, one might think they have been well-studied. Nonetheless, field trips have not been heavily studied, and little research has mapped what actually transpires during field trips. Accordingly, to address this research gap, I asked two related research questions. The first question is a descriptive one: What happens on…

  9. The Use of Field Trips in Air-Photo Interpretation and Remote-Sensing Classes.

    ERIC Educational Resources Information Center

    Giardino, John Richard; Fish, Ernest Bertley

    1986-01-01

    Advocates the use of field trips for improving students' image-interpretation abilities. Presents guidelines for developing a field trip for an aerial-photo interpretation class or a remote-sensing class. Reviews methodology employed, content emphasis, and includes an exercise that was used on a trip. (ML)

  10. Multiple Stages of Weekend Field Trips To Expose Students to Nature: Emphasis on Discovery and Awareness.

    ERIC Educational Resources Information Center

    Krupa, James J.

    2002-01-01

    Describes the three stages of a field trip and reviews stage 1, weekend field trips, which focuses on an organism's morphology, behavior, and ecology. Presents activities on salamanders, small mammals, fish, birds, and bats. Explains the difficulties of weekend trips. (YDS)

  11. The Effectiveness of a Virtual Field Trip (VFT) Module in Learning Biology

    ERIC Educational Resources Information Center

    Haris, Norbaizura; Osman, Kamisah

    2015-01-01

    Virtual Field Trip is a computer aided module of science developed to study the Colonisation and Succession in Mangrove Swamps, as an alternative to the real field trip in Form for Biology. This study is to identify the effectiveness of the Virtual Field Trip (VFT) module towards the level of achievement in the formative test for this topic. This…

  12. Fast-acting nuclear reactor control device

    DOEpatents

    Kotlyar, Oleg M.; West, Phillip B.

    1993-01-01

    A fast-acting nuclear reactor control device for moving and positioning a fety control rod to desired positions within the core of the reactor between a run position in which the safety control rod is outside the reactor core, and a shutdown position in which the rod is fully inserted in the reactor core. The device employs a hydraulic pump/motor, an electric gear motor, and solenoid valve to drive the safety control rod into the reactor core through the entire stroke of the safety control rod. An overrunning clutch allows the safety control rod to freely travel toward a safe position in the event of a partial drive system failure.

  13. Using GIS for planning field trips: In-situ assessment of Geopoints for field trips with mobile devices

    NASA Astrophysics Data System (ADS)

    Böhm, Sarah; Kisser, Thomas; Ditter, Raimund

    2016-04-01

    Up to now no application is existing for collecting data via mobile devices using a geographical information system referring to the evaluation of Geopoints. Classified in different geographical topics a Geopark can be rated for suitability of Geopoints for field trips. The systematically acquisition of the suitability of Geopoints is necessary, especially when doing field trips with lower grade students who see a physical-geographic phenomenon for the first time. For this reason, the development of such an application is an invention for easy handling evaluations of Geopoints on the basis of commonly valid criteria like esthetic attraction, interestingness, and pithiness (Streifinger 2010). Collecting data provides the opportunity of receiving information of particularly suitable Geopoints out of the sight from students, tourists and others. One solution for collecting data in a simple and intuitive form is Survey123 for ArcGIS (http://survey123.esri.com/#/). You can create surveys using an ArcGIS Online organizational account and download your own survey or surveys "that may have been shared with you" (https://itunes.apple.com/us/app/survey-123-for-arcgis/id993015031?mt=8) on your mobile device. "Once a form is downloaded, you will be able to start collecting data."(https://itunes.apple.com/us/app/survey-123-for-arcgis/id993015031?mt=8) Free of cost and use while disconnected the application can easily be used via mobile device on field trips. On a 3-day field trip which is held three times per year in the Geopark Bergstraße-Odenwald Survey123 is being used to evaluate the suitability of different Geopoints for different topics (geology, soils, vegetation, climate). With every field trip about 25 students take part in the survey and evaluate each Geopoint at the route. So, over the time, the docents know exactly which Geopoints suites perfect for teaching geology for example, and why it suites that good. The field trip is organized in an innovative way. Before

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Competing mechanisms in the wear resistance behavior of biomineralized rod-like microstructures

    NASA Astrophysics Data System (ADS)

    Escobar de Obaldia, Enrique; Herrera, Steven; Grunenfelder, Lessa Kay; Kisailus, David; Zavattieri, Pablo

    2016-11-01

    The remarkable mechanical properties observed in biological composite materials relative to those of their individual constituents distinguish them from common engineering materials. Some naturally occurring high-performance ceramics, like the external veneer of the Chiton (Cryptochiton stelleri) tooth, have been shown to have superior hardness and impressive abrasion resistance properties. The mechanical performance of the chiton tooth has been attributed to a hierarchical arrangement of nanostructured magnetite rods surrounded with organic material. While nanoindentation tests provide useful information about the overall performance of this biological composite, understanding the key microstructural features and energy dissipation mechanisms at small scales remains a challenging task. We present a combined experimental/numerical approach to elucidate the role of material deformation in the rods, debonding at the rod interfaces and the influence of energy dissipation mechanisms on the ability of the microstructure to distribute damage under extreme loading conditions. We employ a 3D finite element-based micromechanical model to simulate the nanoindentation tests performed in geological magnetite and cross-sections of the chiton tooth. This proposed model is capable of capturing the inelastic deformation of the rods and the failure of their interfaces, while damage, fracture and fragmentation of the mineralized rods is assessed using a probabilistic function. Our results show that these natural materials achieve their abrasion resistant properties by controlling the interface strength between rods, alleviating the tensile stress on the rods near the indentation tip and therefore decreasing the probability of catastrophic failure without significantly sacrificing resistance to penetration. The understanding of these competing energy dissipating mechanisms provides a path to the prediction of new combination of materials. In turns, these results suggest certain

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Field Trips Put Chemistry in Context for Non-Science Majors

    NASA Astrophysics Data System (ADS)

    Peterman, Keith E.

    2008-05-01

    Field trips can provide excellent real-world learning situations for students in non-science major chemistry courses. The field trips described in this article are accessible, most trips can be completed within a scheduled three-hour laboratory time period, and they can be conducted at minimal cost. These field trips significantly enhanced student learning and contributed to an understanding of the interrelationship of chemistry and societal issues. The experiences gained on these field trips help students "weave" chemistry into the fabric of social, political, economic, and ethical issues within their communities.

  8. Linking impulse response functions to reaction time: Rod and cone reaction time data and a computational model

    PubMed Central

    Cao, Dingcai; Zele, Andrew J.; Pokorny, Joel

    2007-01-01

    Reaction times for incremental and decremental stimuli were measured at five suprathreshold contrasts for six retinal illuminance levels where rods alone (0.002–0.2 Trolands), rods and cones (2–20 Trolands) or cones alone (200 Trolands) mediated detection. A 4-primary photostimulator allowed independent control of rod or cone excitations. This is the first report of reaction times to isolated rod or cone stimuli at mesopic light levels under the same adaptation conditions. The main findings are: 1) For rods, responses to decrements were faster than increments, but cone reaction times were closely similar. 2) At light levels where both systems were functional, rod reaction times were ~20 ms longer. The data were fitted with a computational model that incorporates rod and cone impulse response functions and a stimulus-dependent neural sensory component that triggers a motor response. Rod and cone impulse response functions were derived from published psychophysical two-pulse threshold data and temporal modulation transfer functions. The model fits were accomplished with a limited number of free parameters: two global parameters to estimate the irreducible minimum reaction time for each receptor type, and one local parameter for each reaction time versus contrast function. This is the first model to provide a neural basis for the variation in reaction time with retinal illuminance, stimulus contrast, stimulus polarity, and receptor class modulated. PMID:17346763

  9. Crystallization-Driven Self-Assembly of Rod-Coil-Rod Pseudopolyrotaxanes into Spherical Micelles, Nanorods, and Nanorings in Aqueous Solutions.

    PubMed

    Qi, Rui; Jin, Yong; Cheng, Xinfeng; Fan, Baozhu; Sun, Tongbing; Peng, Shaojun; Li, Hanping

    2015-08-01

    A novel rod-containing block copolymer is constructed by supramacromolecular self-assembly of α-cyclodextrin and a triblock copolymer with methoxy polyethylene glycol as the flanking chains and the midterm block alternately connected by 2,2-dimethylolbutyric acid and isophorone diisocyanate. The assembled rod-containing block copolymer shows an exciting phenomenon of concentration- and pH-dependent morphological switching of well-defined nanostructures. In the solutions at pH 9.2, spherical micelles, rod-like micelles, and hydrogel are observed successively with an increase of the concentration. Notably, the rod-like micelles are composed of spherical segments due to the combination of the crystalline cores of the spherical micelles. In addition, 1D nanostructures with different curvatures from linear rod-like micelles (pH 9.2) to ring-shaped micelles (pH 7.5) can be obtained by controlling the pH values of the assembled systems.

  10. 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.

  11. Integrated modeling and parallel computation of laser-induced axisymmetric rod growth

    NASA Astrophysics Data System (ADS)

    Lan, Hong

    2005-07-01

    To fully investigate a pyrolytic Laser-induced chemical vapor deposition (LCVD) system for growing an axisymmetric rod, a novel integrated three-dimensional mathematical model was developed not only to describe the heat transport in the deposit and substrate, but also to simulate the gas-phase in the heated reaction zone and its effect on growth rate. The integrated model consists of three components: the substrate, rod, and gas-phase domains. Each component is a separate model and the three components are dynamically integrated into one model for simulating the iterative and complex process of rod deposition. The gas-phase reaction is modeled by the gas-phase component, an adaptive domain attached on the top part of the rod. Its size and mesh decomposition is dynamically determined by the rod temperature distribution and the chosen threshold. The temperature and molar ratio are predicted and used to adjust the growth rate, by taking into account the diffusion limited growth regime, and to improve the simulation of entire deposition process. The substrate component describes the heat flow into the substrate, and the substrate surface temperature can be used to predict the initial rod growth which may affect the successive growth of the rod. The rod growth process is simulated using a layer-by-layer axisymmetric model. For each layer, the rod grows along the outward normal direction at each point on the rod surface. This simplified model makes the process more predictable and easier to control by specifying the height of the rod and the number of total iterations. Finite difference schemes, iterative numerical methods, and parallel algorithms were developed for solving the model. The numerical computation is stable, convergent, and efficient. The model and numerical methods are implemented sequentially and in parallel using a standard C++ code and Message Passing Interface (MPI). The program can be easily installed and executed on different platforms, such as Unix

  12. Improvement in J{sub c} performance below liquid nitrogen temperature for SmBa{sub 2}Cu{sub 3}O{sub y} superconducting films with BaHfO{sub 3} nano-rods controlled by low-temperature growth

    SciTech Connect

    Miura, S. Yoshida, Y.; Ichino, Y.; Xu, Q.; Matsumoto, K.; Ichinose, A.; Awaji, S.

    2016-01-01

    For use in high-magnetic-field coil-based applications, the critical current density (J{sub c}) of REBa{sub 2}Cu{sub 3}O{sub y} (REBCO, where RE = rare earth) coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the J{sub c} for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO{sub 3} (BHO) nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique (T{sub s} = 720 °C film). The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1) × 10{sup 3} μm{sup −2} of small (diameter: 4 ± 1 nm), discontinuous nano-rods that grew in various directions, was obtained. In J{sub c} measurements, the J{sub c} of the T{sub s} = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The J{sub c}{sup min} (6.4 MA/cm{sup 2}) of the former was more than 6 times higher than that (1.0 MA/cm{sup 2}) of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m{sup 3} was realized; this value was comparable to the highest value recorded, to date.

  13. The high-speed deformation behavior of TRIP steels

    NASA Astrophysics Data System (ADS)

    Choi, Ildong; Bruce, Denise M.; Matlock, David K.; Speer, John G.

    2008-04-01

    The high-speed deformation behavior of TRIP steel was investigated at strain rates ranging from 10-2 s-1 to 103 s-1. The effects of metallurgical factors, such as the rolling direction, thickness, and gage length, on the tensile properties at various strain rates were evaluated. The ultimate tensile strength, uniform elongation, strain rate sensitivity, absorbed energy, and strain-hardening exponent are reported. In general, the strength increases and the ductility decreases as the strain rate increases. The samples with a high amount of retained austenite had two distinct regions of strain rate sensitivity, showing high strain rate sensitivity over a strain rate of 102 s-1. The tensile properties were not affected by the gage length and thickness of the tensile samples; however, the rolling direction of the tensile samples affected the UTS values slightly. The absorbed energy of the TRIP steel greatly exceeded that of HSLA steel.

  14. Analysis of reactor trips originating in balance of plant systems

    SciTech Connect

    Stetson, F.T.; Gallagher, D.W.; Le, P.T.; Ebert, M.W. )

    1990-09-01

    This report documents the results of an analysis of balance-of-plant (BOP) related reactor trips at commercial US nuclear power plants of a 5-year period, from January 1, 1984, through December 31, 1988. The study was performed for the Plant Systems Branch, Office of Nuclear Reactor Regulation, US Nuclear Regulatory Commission. The objectives of the study were: to improve the level of understanding of BOP-related challenges to safety systems by identifying and categorizing such events; to prepare a computerized data base of BOP-related reactor trip events and use the data base to identify trends and patterns in the population of these events; to investigate the risk implications of BOP events that challenge safety systems; and to provide recommendations on how to address BOP-related concerns in regulatory context. 18 refs., 2 figs., 27 tabs.

  15. Power ascension strategy following a reactor trip during EOC coastdown

    SciTech Connect

    Beard, C.L.; Heibel, M.D. ); Lesnick, D.C. )

    1992-01-01

    The difficulties associated with returning a reactor to the pretrip power level following a reactor trip during an end-of-cycle (EOC) power coastdown maneuver, and maintaining it once achieved, have caused utilities to abandon the restart and enter their refueling outages ahead of schedule. The Commonwealth Edison Company (CECo) Braidwood and Byron units have experienced reactor trips during EOC power coastdown maneuvers and have successfully performed restarts. The installation of the BEACON core monitoring system, which provides core monitoring, measurement reduction, core analysis and follow, and core prediction capability utilizing a very fast and accurate three-dimensional nodal code, at the CECo Byron, Braidwood, and Zion stations allows the reactor engineers at these units to accurately determine reactor response. The capabilities of the BEACON system allow an optimal return to power strategy to be developed and continuously updated. This paper presents a method for establishing the optimal return to power strategy utilizing the BEACON system.

  16. Visiting the USSR: a trip of a lifetime.

    PubMed

    Brown, Geraldine

    2012-01-01

    To Russia, who me? That is actually how it all began. A decade or more ago, I had the opportunity to visit what was then known as the Union of Soviet Socialist Republics (USSR), Russia. Although, this place held high priority on my list of places to go, I never thought such a trip was within my reach. This idea was quite fascinating to me because of the events that did happen there, including the Russian space ship Sputnik and the dog, the high stepping military officers, Red Square and the St. Basil's Cathedral. After reading a lot about Russia, I thought it would be great to see a clean place, where it was unlawful to throw paper on the streets, and ride in public transportation such as the buses, taxis and the subway system, which were immaculately clean. It was an exciting trip, one, I will always remember, but would be a difficult adjustment to make, to live.

  17. 10 years after implementation of TRIPS obligations in India.

    PubMed

    Pawar, Mahesh D

    2015-01-01

    The Patent (Amendment) Act of 2005 enforced after TRIPS raises many issues which hinder growth of Indian pharma companies. To tackle this, Indian pharma companies doubled their R&D expenditure and became significant players in global generic drug market. Indian pharmaceutical companies, which predominantly focused on import-oriented market, shifted to research-based approach by signing various agreements with MNCs that led to M&A and technology transfer. At the same time growth in R&D activities increased ANDA and DMF filing in the USA and Europe. Companies also kept their social responsibility by selling medicines at affordable price to patients. This paper highlights the changing business scenario of Indian pharmaceutical companies to counteract various issues evolved from new patent regime after TRIPS.

  18. Acquisition of background and technical information and class trip planning

    NASA Technical Reports Server (NTRS)

    Mackinnon, R. M.; Wake, W. H.

    1981-01-01

    Instructors who are very familiar with a study area, as well as those who are not, find the field trip information acquisition and planning process speeded and made more effective by organizing it in stages. The stage follow a deductive progression: from the associated context region, to the study area, to the specific sample window sites, and from generalized background information on the study region to specific technical data on the environmental and human use systems to be interpreted at each site. On the class trip and in the follow up laboratory, the learning/interpretive process are at first deductive in applying previously learned information and skills to analysis of the study site, then inductive in reading and interpreting the landscape, imagery, and maps of the site, correlating them with information of other samples sites and building valid generalizations about the larger study area, its context region, and other (similar and/or contrasting) regions.

  19. Probing the characteristic deformation behavior of TRIP steels

    SciTech Connect

    Cheng, Sheng; Wang, Xun-Li; Feng, Zhili; Clausen, Bjorn; Choo, Hahn; Liaw, Peter K

    2008-01-01

    Tensile behavior of two TRIP steels was investigated by in situ neutron diffraction. In the sample with a higher fraction of retained-austenite, the first load transfer was observed from the soft ferrite matrix to the hard retained austenite prior to martensitic transformation, while a second load transfer occurred from the austenite to the harder martensite as martensitic transformation was induced. In the sample with less retained-austenite, the martensitic transformation was limited, leading to significantly less tensile ductility.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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…

  6. 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 ...

  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. 46 CFR 62.35-50 - Tabulated monitoring and safety control requirements for specific systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) System Service Instrumentation Alarm Safety control Notes Main (Propulsion) boiler (1) (1) (1) (2) Supply... Status Main (Propulsion steam) turbine (2) (2) (2) (4, 5) Manual trip Main propulsion, diesel (1) (1) (1) (4, 5) Manual trip Main propulsion, remote control Failure ......ditto Auto safety trip...

  13. 46 CFR 62.35-50 - Tabulated monitoring and safety control requirements for specific systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) System Service Instrumentation Alarm Safety control Notes Main (Propulsion) boiler (1) (1) (1) (2) Supply... Status Main (Propulsion steam) turbine (2) (2) (2) (4, 5) Manual trip Main propulsion, diesel (1) (1) (1) (4, 5) Manual trip Main propulsion, remote control Failure ......ditto Auto safety trip...

  14. 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

  15. 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

  16. 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

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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

  3. 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.

  4. Mechanisms influencing student understanding on an outdoor guided field trip

    NASA Astrophysics Data System (ADS)

    Caskey, Nourah Al-Rashid

    Field trips are a basic and important, yet often overlooked part of the student experience. They provide the opportunity to integrate real world knowledge with classroom learning and student previous personal experiences. Outdoor guided field trips leave students with an increased understanding, awareness and interest and in science. However, the benefits of this experience are ambiguous at best (Falk and Balling, 1982; Falk and Dierking, 1992; Kisiel, 2006.) Students on an outdoor guided field trip to a local nature park experienced a significant increase in their understanding of the rock cycle. The changes in the pre-field trip test and the post-field trip test as well as their answers in interviews showed a profound change in the students' understanding and in their interest in the subject matter. The use of the "student's voice" (Bamberger and Tal, 2008) was the motivation for data analysis. By using the students' voice, I was able to determine the mechanisms that might influence their understanding of a subject. The central concepts emerging from the data were: the outdoor setting; the students' interest; the social interaction. From these central concepts, a conceptual model was developed. The outdoor setting allows for the freedom to explore, touch, smell and movement. This, in turn, leads to an increased interest in subject matter. As the students are exploring, they are enjoying themselves and become more open to learning. Interest leads to a desire to learn (Dewey, 1975). In addition to allowing the freedom to explore and move, the outdoor setting creates the condition for social interaction. The students talk to each other as they walk; they have in-depth discourse regarding the subject matter---with the teachers, each other and with the guides. The guides have an extremely important role in the students' learning. The more successful guides not only act as experts, but also adjust to the students' needs and act or speak accordingly. The

  5. 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

  6. Determination of Biology Department Students' Past Field Trip Experiences and Examination of Their Self-Efficacy Beliefs in Planning and Organising Educational Field Trips

    ERIC Educational Resources Information Center

    Bozdogan, Aykut Emre

    2015-01-01

    The purpose of this study is to determine the past field trip experiences of pre-service teachers who are graduates of Faculty of Sciences, Department of Biology and who had pedagogical formation training certificate and to examine their self-efficacy beliefs in planning and organizing field trips with regard to different variables. The study was…

  7. Spreading Geodiversity awareness in schools through field trips and ICT

    NASA Astrophysics Data System (ADS)

    Magagna, Alessandra; Giardino, Marco; Ferrero, Elena

    2014-05-01

    Geodiversity, unlike Biodiversity, is not a topic included in the Italian schools curriculum. Nevertheless, Geomorphology is taught at all levels, and it seems to be the right tool for introducing the students to the concepts related to Geodiversity. In this context, a research on the use of field trips and Information and Communication Technologies (ICT) is being carried out for spreading the value of Geodiversity in Secondary Schools. Relevant international literature states that field trips are effective didactic tools for Earth Science education, because they stimulate an active learning process and allow students to appreciate the geological complexity of an area. On the other side, ICT allow students to get knowledge about the variety of landforms of their own territory by staying indoor, using virtual field trips and free software like Google Earth, Google Maps, Bing etc. In order to connect the two strategies, an innovative educational project is proposed here; it involves both the indoor and the outdoor activities, by enhancing a critical approach to the complexity of geological processes. As a starting point, a multimedia product on 20 Italian geological tours, designed for analyzing Geodiversity at a regional scale, has been tested with teachers and students, in order to understand its effectiveness by using it solely indoor. In a second phase, teachers and students have been proposed to compare and integrate indoor and outdoor activities to approach Geodiversity directly at a local scale, by means of targeted field trips. For achieving this goal, during the field trips, students used their mobile devices (smartphone and tablet) equipped with free and/or open source applications (Epicollect, Trimble Outdoor Navigator). These tools allow to track field trips, to gather data (geomorphological observations and related photographs), and to elaborate them in the laboratory; a process useful for reasoning on concepts such as spatial and temporal scales and for

  8. Predictive Process Optimization for Fracture Ductility in Automotive TRIP Steels

    NASA Astrophysics Data System (ADS)

    Gong, Jiadong

    In light of the emerging challenges in the automotive industry of meeting new energy-saving and environment-friendly requirements imposed by both the government and the society, the auto makers have been working relentlessly to reduce the weight of automobiles. While steel makers pushed out a variety of novel Advanced High Strength Steels (AHSS) to serve this market with new needs, TRIP (Transformation Induced Plasticity) steels is one of the most promising materials for auto-body due to its exceptional combination of strength and formability. However, current commercial automotive TRIP steels demonstrate relatively low hole-expansion (HE) capability, which is critical in stretch forming of various auto parts. This shortcoming on ductility has been causing fracture issues in the forming process and limits the wider applications of this steel. The kinetic theory of martensitic transformations and associated transformation plasticity is applied to the optimization of transformation stability for enhanced mechanical properties in a class of high strength galvannealed TRIP steel. This research leverages newly developed characterization and simulation capabilities, supporting computational design of high-performance steels exploiting optimized transformation plasticity for desired mechanical behaviors, especially for the hole-expansion ductility. The microstructure of the automotive TRIP sheet steels was investigated, using advanced tomographic characterization including nanoscale Local Electrode Atom Probe (LEAP) microanalysis. The microstructural basis of austenite stability, the austenite carbon concentration in particular, was quantified and correlated with measured fracture ductility through transformation plasticity constitutive laws. Plastic flow stability for enhanced local fracture ductility at high strength is sought to maintain high hole-expansion ductility, through quantifying the optimal stability and the heat-treatment process to achieve it. An additional

  9. Assessment of full power turbine trip start-up test for C. Trillo 1 with RELAP5/MOD2. International Agreement Report

    SciTech Connect

    Lozano, M.F.; Moreno, P.; de la Cal, C.; Larrea, E.; Lopez, A.; Santamaria, J.G.; Lopez, E.; Novo, M.

    1993-07-01

    C. Trillo I has developed a model of the plant with RELAP5/MOD2/36.04. This model will be validated against a selected set of start-up tests. One of the transients selected to that aim is the turbine trip, which presents very specific characteristics that make it significantly different from the same transient in other PWRs of different design, the main difference being that the reactor is not tripped: a reduction in primary power is carried out instead. Pre-test calculations were done of the Turbine Trip Test and compared against the actual test. Minor problems in the first model, specially in the Control and Limitation Systems, were identified and post-test calculations had been carried out. The results show a good agreement with data for all the compared variables.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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...

  15. 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.

  16. Transduction heats in retinal rods: tests of the role of cGMP by pyroelectric calorimetry.

    PubMed Central

    Hagins, W A; Ross, P D; Tate, R L; Yoshikami, S

    1989-01-01

    The sensory dark current of vertebrate retinal rods is believed to be controlled by light activation of a chain of coupled biochemical cycles that finally regulate the cationic conductance of the plasma membrane by hydrolytically reducing the level of cGMP in rod outer segment cytoplasm. The scheme has been tested by measuring heat production by live frog retinas when stimulated with sequences of light flashes of progressively increasing energy. Using pyroelectric poly(vinylidene 1,1-difluoride) detectors that simultaneously measure transretinal voltage and retinal temperature change, four heat effects assignable to known biochemical cycles in rods have been found. As the dark current shuts down after a flash causing 180-1800 rhodopsin photoisomerizations per rod, a heat burst, q1, raises the retinal temperature 1-2 microK. q1 is closely regulated in size and slightly precedes dark current shutdown. Isobutylmethylxanthine slows and enlarges q1, delaying the dark-current response. Increasing cytoplasmic Ca2+ stops the dark current without affecting q1. Although rod heat production is consistent with splitting of 1-3 microM of free cytoplasmic cGMP during transduction, the kinetics of the two processes do not match the predictions of current cGMP control models. PMID:2537492

  17. Treatment of neuromuscular scoliosis with posterior spinal fusion using the Galveston procedure: retrospective of eight years of experience with unit rod instrumentation.

    PubMed

    Gregg, Fredrick O'Neal; Zhou, Haitao; Bertrand, Styles Leslie

    2012-01-01

    Posterior spinal fusion with instrumentation to the pelvis (the Galveston Procedure) is widely accepted as an effective treatment for neuromuscular scoliosis. Unit rod instrumentation is commonly used in these cases, but it is not universally accepted as superior to separate Luque rods. This study is a retrospective review of 115 consecutive cases in which the unit rod was used. The following statistics were collected from the records of these patients: operative time, estimated blood loss, PICU stay, hospital stay, transfusion rate, complication rate, scoliosis correction, and correction of pelvic obliquity . Results at 2-year follow-up were compared to those reported in the literature and to results previously reported from the same facility in which separate Luque rods were used. The unit rod provides excellent control of pelvic obliquity and superior scoliosis correction compared with separate Luque rods. Improvements were also found in reduced operative times, lower blood loss, a lower complication rate, and shorter hospital stay.

  18. Tripping Elicits Earlier and Larger Deviations in Linear Head Acceleration Compared to Slipping

    PubMed Central

    Arena, Sara L.; Davis, Julian L.; Grant, J. Wallace; Madigan, Michael L.

    2016-01-01

    Slipping and tripping contribute to a large number of falls and fall-related injuries. While the vestibular system is known to contribute to balance and fall prevention, it is unclear whether it contributes to detecting slip or trip onset. Therefore, the purpose of this study was to investigate the effects of slipping and tripping on head acceleration during walking. This information would help determine whether individuals with vestibular dysfunction are likely to be at a greater risk of falls due to slipping or tripping, and would inform the potential development of assistive devices providing augmented sensory feedback for vestibular dysfunction. Twelve young men were exposed to an unexpected slip or trip. Head acceleration was measured and transformed to an approximate location of the vestibular system. Peak linear acceleration in anterior, posterior, rightward, leftward, superior, and inferior directions were compared between slipping, tripping, and walking. Compared to walking, peak accelerations were up to 4.68 m/s2 higher after slipping, and up to 10.64 m/s2 higher after tripping. Head acceleration first deviated from walking 100-150ms after slip onset and 0-50ms after trip onset. The temporal characteristics of head acceleration support a possible contribution of the vestibular system to detecting trip onset, but not slip onset. Head acceleration after slipping and tripping also appeared to be sufficiently large to contribute to the balance recovery response. PMID:27802298

  19. TRIP13 is expressed in colorectal cancer and promotes cancer cell invasion

    PubMed Central

    Kurita, Kenji; Maeda, Masao; Mansour, Mohammed A.; Kokuryo, Toshio; Uehara, Keisuke; Yokoyama, Yukihiro; Nagino, Masato; Hamaguchi, Michinari; Senga, Takeshi

    2016-01-01

    Thyroid hormone receptor interactor 13 (TRIP13) is a member of the ATPases associated with various cellular activities family of proteins and is highly conserved in a wide range of species. Recent studies have demonstrated that TRIP13 is critical for the inactivation of the spindle assembly checkpoint and is associated with the progression of certain cancers. In the present study, the role of TRIP13 in colorectal cancer (CRC) was examined. Reverse transcription-quantitative polymerase chain reaction analysis revealed that TRIP13 messenger RNA was highly expressed in multiple CRC tissues. The depletion of TRIP13 in CRC cells suppressed cell proliferation, migration and invasion. To determine whether the catalytic activity of TRIP13 was critical for cancer progression, an inactive mutant of TRIP13 was expressed in CRC cells. The invasion of cancer cells that expressed the mutant TRIP13 was significantly reduced compared with that of the wild type TRIP13-expressing cancer cells. These results indicate that TRIP13 could be a potential target for CRC treatment. PMID:28105232

  20. Galvanizability of Advanced High-Strength Steels 1180TRIP and 1180CP

    NASA Astrophysics Data System (ADS)

    Kim, M. S.; Kwak, J. H.; Kim, J. S.; Liu, Y. H.; Gao, N.; Tang, N.-Y.

    2009-08-01

    In general, Si-bearing advanced high-strength steels (AHSS) possess excellent mechanical properties but poor galvanizability. The galvanizability of a transformation-induced plasticity (TRIP) steel 1180TRIP containing 2.2 pct Mn and 1.7 pct Si and a complex phase steel 1180CP containing 2.7 pct Mn and 0.2 pct Si was extensively studied using a galvanizing simulator. The steel coupons were annealed at fixed dew points in the simulator. The surface features of the as-annealed steel coupons, together with galvanized and galvannealed coatings, were carefully examined using a variety of advanced analysis techniques. It was found that various oxides formed on the surface of these steels, depending on the steel composition and on the dew point control. Coating quality was good at 0 °C dew point but deteriorated as the dew point decreased to -35 °C and -65 °C. Based on the findings, guidance was provided for improving galvanizability by adjusting the Mn:Si ratio in steel compositions according to the dew point.