Science.gov

Sample records for mm rod constructs

  1. 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.

  2. The Construct Validity of the Rod and Frame Test.

    ERIC Educational Resources Information Center

    Schroeder, David H.

    This study examined the construct validity of the Rod and Frame Test (RFT). Subjects were 554 clients (269 males and 285 females) (aged 14 to 65 years) of the Johnson O'Connor Research Foundation (JOCRF), a vocational guidance service. In a battery of diverse ability and style tests (19 tests of the JOCRF battery and 4 tests of cognitive style),…

  3. Use of MM-Paths in constructive software development

    SciTech Connect

    Jorgensen, P.C.

    1985-01-01

    Systems such as nuclear reactors, weapons systems, and real-time switching systems present a variety of problems for conventional software development. In addition to the sheer magnitude of these systems, high reliability requirements and deep complexities best characterized by Petri nets demand improvements in specification, design, and testing. Specification of such systems is considered: traditional functional decomposition is shown to be inadequate, as is the approach based on Finite State Machines. A rigorous form of process descriptions is developed here; these are demonstrated to have the same expressive power as Petri nets. Use of these process descriptions as a specification technique leads naturally to a truly intermediate level concept, the MM-path, which is the basis of the development methodology proposed here. This methodology is highly constructive in the sense that information needed in later phases is used to populate a database structured by the process description and MM-Path concepts. Sample queries are given to illustrate the use of the database in the software testing phases. Test coverage metrics are developed for the unit, integration, and system levels of software testing. Existing unit test coverage metrics are shown to be upper bounds to the unit test coverage metrics defined here. A lattice of four integration test coverage metrics is defined in terms of MM-Paths, and MM-Paths are used to extend the concepts of path analysis to system level testing.

  4. TECHNICAL NOTE: Characteristic analysis of an ultrasonic micromotor using a 3 mm diameter piezoelectric rod

    NASA Astrophysics Data System (ADS)

    Chu, Xiangcheng; Yan, Li; Li, Longtu

    2004-04-01

    Smart systems and devices generally use certain microstructures, e.g. rod- and strip-shaped structures. In this paper, a miniaturized piezoelectric rod is analysed using the finite element method (FEM) and a laser scanning vibrometer (LSV). The effects of some factors, including the detailed structure, material parameters and input voltage, on the resonant frequencies and vibration behaviors of a piezoelectric rod are studied. On the basis of experimental results, the vibration modes of the piezoelectric rod can be made available for use in fabricating an ultrasonic micromotor or piezoelectric actuators of other types. The prototype motor fabricated here has a maximum output torque of 410 µN m for a stainless steel stator and 360 µN m for a copper stator. This article was originally published in 2003 by the Israel Academy of Sciences and Humanities in the framework of its Albert Einstein Memorial Lectures series. Reprinted by permission of the Israel Academy of Sciences and Humanities.

  5. Laser amplifier based on a neodymium glass rod 150 mm in diameter

    SciTech Connect

    Shaykin, A A; Fokin, A P; Soloviev, A A; Kuzmin, A A; Shaikin, I A; Burdonov, K F; Khazanov, E A; Charukhchev, A V

    2014-05-30

    A unique large-aperture neodymium glass rod amplifier is experimentally studied. The small-signal gain distribution is measured at different pump energies. The aperture-averaged gain is found to be 2.3. The stored energy (500 J), the maximum possible pump pulse repetition rate, and the depolarisation in a single pulse and in a series of pulses with a repetition rate of one pulse per five minutes are calculated based on the investigations performed. It is shown that the use of this amplifier at the exit of the existing laser can increase the output pulse energy from 300 to 600 J. (lasers)

  6. Construction of exchange repulsion in terms of the wave functions at QM/MM boundary region

    SciTech Connect

    Takahashi, Hideaki Umino, Satoru; Morita, Akihiro

    2015-08-28

    We developed a simple method to calculate exchange repulsion between a quantum mechanical (QM) solute and a molecular mechanical (MM) molecule in the QM/MM approach. In our method, the size parameter in the Buckingham type potential for the QM solute is directly determined in terms of the one-electron wave functions of the solute. The point of the method lies in the introduction of the exchange core function (ECF) defined as a Slater function which mimics the behavior of the exterior electron density at the QM/MM boundary region. In the present paper, the ECF was constructed in terms of the Becke-Roussel (BR) exchange hole function. It was demonstrated that the ECF yielded by the BR procedure can faithfully reproduce the radial behavior of the electron density of a QM solute. The size parameter of the solute as well as the exchange repulsion are, then, obtained using the overlap model without any fitting procedure. To examine the efficiency of the method, it was applied to calculation of the exchange repulsions for minimal QM/MM systems, hydrogen-bonded water dimer, and H{sub 3}O{sup +}–H{sub 2}O. We found that our approach is able to reproduce the potential energy curves for these systems showing reasonable agreements with those given by accurate full quantum chemical calculations.

  7. DESIGN AND CONSTRUCTION OF A 15 T, 120 MM BORE IR QUADRUPOLE MAGNET FOR LARP

    SciTech Connect

    Caspi, S.; Cheng, D.; Dietderich, D.; Felice, H.; Ferracin, P.; Hafalia, R.; Hannaford, R.; Sabbi, G. S.; Anerella, M.; Ghosh, A.; Schmalzle, J.; Wanderer, P.; Ambrosio, G.; Bossert, R.; Kashikhin, V.; Pasholk, D.; Zlobin, A.

    2009-05-04

    Pushing accelerator magnets beyond 10 T holds a promise of future upgrades to machines like the Large Hadron Collider (LHC) at CERN. Nb{sub 3}Sn conductor is at the present time the only practical superconductor capable of generating fields beyond 10 T. In support of the LHC Phase-II upgrade, the US LHC Accelerator Research Program (LARP) is developing a large bore (120 mm) IR quadrupole (HQ) capable of reaching 15 T at its conductor peak field and a peak gradient of 219 T/m at 1.9 K. While exploring the magnet performance limits in terms of gradient, forces and stresses the 1 m long two-layer coil will demonstrate additional features such as alignment and accelerator field quality. In this paper we summarize the design and report on the magnet construction progress.

  8. 75 FR 68334 - Record of Decision (ROD) for Training Range and Garrison Support Facilities Construction and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-05

    ..., and Soldier and Family quality of life considerations. ADDRESSES: To request a copy of the ROD, please... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Army Record of Decision (ROD) for Training Range and Garrison Support...

  9. Construction of a 56 mm aperture high-field twin-aperture superconducting dipole model magnet

    SciTech Connect

    Ahlbaeck, J; Leroy, D.; Oberli, L.; Perini, D.; Salminen, J.; Savelainen, M.; Soini, J.; Spigo, G.

    1996-07-01

    A twin-aperture superconducting dipole model has been designed in collaboration with Finnish and Swedish Scientific Institutions within the framework of the LHC R and D program and has been built at CERN. Principal features of the magnet are 56 mm aperture, separate stainless steel collared coils, yoke closed after assembly at room temperature, and longitudinal prestressing of the coil ends. This paper recalls the main dipole design characteristics and presents some details of its fabrication including geometrical and mechanical measurements of the collared coil assembly.

  10. Construction and manufacturing of a microgearhead with 1.9-mm outer diameter for universal application

    NASA Astrophysics Data System (ADS)

    Thuerigen, Christian; Beckord, Ulrich; Bessey, Reiner

    1999-03-01

    Many new applications in medicine, telecommunication, automation systems etc. require powerful microdrives. Speeds up to 100.000 rpm and output torques in the (mu) Nm-range are typical characteristics of electromagnetic micromotors with diameters of a few millimeters. To accomplish a powerful microdrive, these micromotors have to be combined with micro gearheads of the same outer diameter. For such a micro gearhead with toothed wheels manufactured by use of the LIGA process a multi-stage planetary gear has many advantages. Many stages with different gear ratios can be combined to achieve a great number of different transmission, but manufacturing tolerances and a clearance for assembly must be respected. Therefore besides the selection of a reliable gearhead type and a suitable manufacturing process the optimization of the tooth profile is the key to the implementation of powerful micro gear systems with high output torques and efficiencies. The involute profile is the most suitable toothing, but many calculations and simulations are required to find the right modulus, total depth of teeth, profile offset etc. In a joint project Dr. Fritz Faulhaber GmbH and Co. KG and the Institut fuer Mikrotechnik Mainz GmbH developed a powerful microdevice with an outer diameter of only 1.9 mm.

  11. 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

  12. 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.

  13. Rodding Surgery

    MedlinePlus

    ... Rods can be made of stainless steel or titanium. Regular rods do not expand. They have many ... v regular), the rod materials (stainless steel v titanium) and the age for a first rodding surgery. ...

  14. Rod guide

    SciTech Connect

    Sable, D.E.

    1988-11-29

    This patent describes a rod guide assembly for a sucker rod longitudinally reciprocably movable in a well flow conductor comprising: a pair of longitudinally spaced upper and lower stops rigidly secured to a sucker rod; and a guide body movably mounted on the rod between the stops. The stops being spaced from each other a distance slightly greater than the length of the guide body, the upper stop engaging the guide body to move the guide body downwardly with the rod after an initial short downward movement of the rod after initiation of each downward movement of the rod and the lower stop engaging the guide body to move the second guide body upwardly with the rod after initial short upward movement of the rod after initiation of each upward movement of the rod during the longitudinal reciprocatory movement of the rod in a well flow conductor.

  15. Bacteria-Directed Construction of ZnO/CdS Hollow Rods and Their Enhanced Photocatalytic Activity.

    PubMed

    Ge, Shengsong; Zhang, Qiaoxia; Wang, Xiutong; Shao, Qian; Bao, Liwei; Ding, Rui; Liu, Qingyun

    2016-05-01

    Zinc oxide (ZnO) hollow rods were fabricated by precipitation method with Bacillus subtilis as template. CdS nanoparticles were then decorated on the surface of the ZnO rods through hydrothermal method. The as-prepared samples were characterized using X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscope and ultraviolet-visible spectroscopy techniques. The ZnO/CdS composite hollow rods copied the morphology of Bacillus subtiis. A possible formation mechanism of the rods was proposed. The photocatalytic activity of the samples was further evaluated through the photodegradation of Rhodamine B under a simulated solar-light irradiation. Results indicated that the photocatalytic activity of the rods improved greatly. PMID:27483848

  16. Prototypical Rod Construction Demonstration Project. Phase 3, Final report: Volume 1, Cold checkout test report, Book 3

    SciTech Connect

    Not Available

    1993-05-01

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

  17. Design and construction of a one-metre model of the 70 mm aperture quadrupole for the LHC low-{beta} insertions

    SciTech Connect

    Ostojic, R.; Taylor, T.M.; Kirby, G.A.

    1994-07-01

    In order to achieve high field quality and low current rating of the 250 T/m quadrupoles for the LHC low-{beta} insertions, a design based on a graded four-layer coil with an aperture of 70 mm, wound from NbTi conductor cooled at 1.8 K, has been proposed. Its mechanical structure is based on the collar-spacer concept, where a thin collar serves for coil assembly only. The iron yoke has both important magnetic and structural functions, since the magnetic forces are taken by the rigidity of the iron lamination pack. The coil and cable parameters are derived for this particular structure, and the results of the structural analysis of the magnet are presented. A one-meter model of the quadrupole is presently under construction; its features are described and some initial cable tests reported.

  18. mm-wave antenna

    NASA Astrophysics Data System (ADS)

    Muhs, H. P.

    1985-07-01

    The present low profile seeker front end's slotted waveguide antenna was primarily developed to investigate the feasibility of the application of standard manufacturing techniques to mm-wave hardware. A dual plane monopulse comparator was constructed to mate with the antenna via integrated packaging techniques. The comparator was fabricated by CAD/CAM milling operations.

  19. COMPOSITE CONTROL ROD

    DOEpatents

    Rock, H.R.

    1963-12-24

    A composite control rod for use in controlling a nuclear reactor is described. The control rod is of sandwich construction in which finned dowel pins are utilized to hold together sheets of the neutron absorbing material and nonabsorbing structural material thereby eliminating the need for being dependent on the absorbing material for structural support. The dowel pins perform the function of absorbing the forces due to differential thermal expansion, seating further with the fins into the sheets of material and crushing before damage is done either to the absorbing or non-absorbing material. (AEC)

  20. The fatigue life of contoured cobalt chrome posterior spinal fusion rods.

    PubMed

    Nguyen, T-Q; Buckley, J M; Ames, C; Deviren, V

    2011-02-01

    Intraoperative contouring of posterior rods in lumbar arthrodesis constructs introduces stress concentrations that can substantially reduce fatigue life. The sensitivity of titanium (Ti) and stainless steel (SS) to intraoperative contouring has been established in the literature; however, notch sensitivity has yet to be quantified for cobalt chrome (CoCr), which is now being advocated for use in posterior arthrodesis constructs. The goal of this study is to evaluate the sensitivity of CoCr rods to intraoperative contouring for posterior lumbar screwrod arthrodesis constructs. In this paper lumbar bilateral vertebrectomy models are constructed based on ASTM F1717-01 with curved rods (26-30 degrees total curvature) and poly-axial pedicle screws. Three types of constructs are assembled: first, 5.5 mm SS rods with SS screws (6.5 x 35 mm), second, 6.0 mm Ti rods with Ti screws (7.5 x 35 mm), and third, 6.0 mm CoCr rods with Ti screws (7.5 x 35 mm). All specimens are tested at 4 Hz in dynamic axial compression-bending with a load ratio of ten and maximum load levels of 250, 400, and 700 N until run-out at 2 000 000 cycles. Results are presented that show that the fatigue life of CoCr constructs tend to be greater than Ti constructs at all levels. At the 400 N maximum loading, CoCr lasts an average of 350 000 cycles longer than the Ti constructs. The CoCr constructs are able to sustain the 250 N load until run-out at 2 000 000 cycles but they fail at high load levels (maximum 700 N). The CoCr constructs fail at the neck of the Ti screw at high loads whereas Ti screws fail at the notch induced by contouring. Since CoCr is compatible with magnetic resonance imaging and has high static strength characteristics, the results of this study suggest that it may be an appropriate substitute for Ti. PMID:21428153

  1. 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.

  2. Primeval galaxies in the sub-mm and mm

    NASA Technical Reports Server (NTRS)

    Bond, J. Richard; Myers, Steven T.

    1993-01-01

    Although the results of COBE's FIRAS experiment 1 constrain the deviation in energy from the CMB blackbody in the 500-5000 micron range to be delta E/E, sub cmb less than 0.005, primeval galaxies can still lead to a brilliant sub-mm sky of non-Gaussian sources that are detectable at 10 inch resolution from planned arrays such as SCUBA on the James Clerk Maxwell Telescope and, quite plausibly, at sub-arcsecond resolution in planned mm and sub-mm interferometers. Here, we apply our hierarchical peaks method to a CDM model to construct sub-mm and mm maps of bursting PG's appropriate for these instruments with minimum contours chosen to correspond to realistic observational parameters for them and which pass the FIRAS limits.

  3. Impact of AD995 alumina rods

    SciTech Connect

    Chhabildas, L.C.; Furnish, M.D.; Reinhart, W.D.; Grady, D.E.

    1997-10-01

    Gas guns and velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstrate that (1) a time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split Hopkinson bar and shock-loading techniques.

  4. Investigation of Minimum Film boiling Phenomena on Fuel Rods Under Blowdown Cooling Conditions

    SciTech Connect

    Stephen M. Bajorek; Michael Gawron; Timothy Etzel; Lucas Peterson

    2003-06-30

    Blowdon cooling heat transfer is an important process that occurs early in a hypothetical large break loss-of-coolant accident (LOCA) in a pressurized water reactor. During blowdown, the flow through the hot assembly is a post-critical heat flux dispersed droplet flow. The heat transfer mechanisms that occur in blowdown cooling are complex and depend on droplet and heated surface interaction. In a safety analysis, it is of considerable importance to determine the thermal-hydraulic conditions leading to the minimum film boiling temperature, Tmin. A flow boiling rig for measurement of blowdown cooling heat transfer and quench phenomena on a nuclear fuel rod simulator was designed and constructed for operation at up to 12.4 MPa. The test section consisted of a concentric annulus, with a 9.5 mm OD nuclear fuel rod simulator at the center. The rod was contained within a 0.85 mm thick, 19 mm OD 316 stainless steel tube, forming the flow channel. Two types of rods were tested; one type was sheathed with Inconel 600 while the other was clad with Zircaloy-2. Water was injected into the test section at the top of the heated length through an injection header. This header was an annular sign that fit around the fuel rod simulator and within the stainless steel tube. Small spacers aligned the injection header and prevented contract with either the heater rod or the tube. A series of small diameter holes at the bottom of the header caused the formation of droplets that became entrained with the steam flow. The test section design was such that quench would take place on the rod, and not along the channel outer annulus.

  5. 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.

  6. 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.

  7. Measurements of lightning rod responses to nearby strikes

    NASA Astrophysics Data System (ADS)

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

    2000-05-01

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

  8. Airflow produced by dielectric barrier discharge between asymmetric parallel rod electrodes

    NASA Astrophysics Data System (ADS)

    Hayashi, Kazuo; Tanaka, Motofumi; Yasui, Hiroyuki; Hashimoto, Kiyoshi

    2007-09-01

    We observed a novel type of airflow produced by an atmospheric rf discharge between asymmetric parallel rod electrodes. The electrodes were a bare metal rod 1mm in diameter and a glass-coated metal rod 3.2mm in diameter. The thrust, measured by a pendulum, increased with discharge input power.

  9. Airflow produced by dielectric barrier discharge between asymmetric parallel rod electrodes

    SciTech Connect

    Hayashi, Kazuo; Tanaka, Motofumi; Yasui, Hiroyuki; Hashimoto, Kiyoshi

    2007-09-15

    We observed a novel type of airflow produced by an atmospheric rf discharge between asymmetric parallel rod electrodes. The electrodes were a bare metal rod 1 mm in diameter and a glass-coated metal rod 3.2 mm in diameter. The thrust, measured by a pendulum, increased with discharge input power.

  10. Control rod drive

    DOEpatents

    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.

  11. 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.

  12. 1987 Sucker rod tables

    SciTech Connect

    Not Available

    1987-03-01

    This reference identifies manufacturers qualified to produce API sucker rods and related equipment, lists chemical and mechanical properties of the various types of rods and provides dimensional characteristics. In addition, similar information is given for non-API products such as fiberglass and hollow rods.

  13. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  15. Wear resistant rod guide

    SciTech Connect

    Gray, K.W.

    1991-12-03

    This paper describes a sucker rod guide. It comprises: a series of sucker rods connected end to end forming a sucker rod string, the sucker rod string extending down into a tubing string of a producing oil well from a pump jack located on the surface of the ground above the tubing string to a pump located at a bottom end of the tubing string, the pump forces produced fluid collected at the bottom end of the tubing string up to the ground's surface, the produced fluid occupies a space between the rod string and the tubing string through which the fluid is channeled from the bottom end of the tubing string to the ground's surface, the pump jack raises and lowers the rod string in the fluid being pumped up the tubing string while the fluid bathes the rod string within the tubing string, wherein the improvement comprises the following structure in combination with the above.

  16. Sucker rod guide

    SciTech Connect

    Edwards, B.J.; Starks, J.A.

    1989-08-22

    This patent describes a sucker rod guide for mounting on a sucker rod and spacing the sucker rod from the tubing in an oil well. The guide comprising a generally cylindrically-shaped, extruded, ultra-high density polyethylene body having a substantially smooth outside surface; a longitudinal bore provided centrally of the body. The bore having a smaller diameter than the diameter of the sucker rod; a plurality of grooves provided in circumferential relationship in the bore; and a tapered slot extending longitudinally through the body from the outside surface to the bore. The tapered slot further comprising a slot mouth located at the outside surface and a slot throat spaced from the slot mouth. The slot throat lying adjacent to the sucker rod bore and wherein the slot throat is wider than the slot mouth for mounting the sucker rod guide on the sucker rod.

  17. Low turbulence rod guide

    SciTech Connect

    Olinger, E.L.

    1992-05-26

    This patent describes an improved sucker rod guide for fixedly engaging around a sucker rod at a selected location along the length of the rod. It comprises a substantially cylindrical polymeric body having a longitudinal axis, a terminal end substantially continually tapered to the rod, a radially-inward surface and a radially outward surface, the radially inward surface of the body adjacent to and in tripping engagement with the rod when the rod guide is fixedly engaged around the rod; and a plurality of substantially continuous, longitudinal vanes carried by the body, a vane having a selected length and width, and longitudinally disposed along the radially outward surface of the guide body, extending radially away from the guide body and having a radially outside wear surface.

  18. 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)

  19. Pull rod assembly

    DOEpatents

    Cioletti, O.C.

    1988-04-21

    A pull rod assembly comprising a pull rod having three peripheral grooves, a piston device including an adaptor ring and a seal ring, said piston device being mounted on the pull rod by a split ring retainer situated in one groove and extending into an interior groove in the adaptor and a resilient split ring retained in another groove and positioned to engage the piston device and to retain the seal on its adaptor.

  20. Pull rod assembly

    DOEpatents

    Cioletti, Olisse C.

    1990-01-01

    A pull rod assembly comprising a pull rod having three peripheral grooves, a piston device including an adaptor ring and a seal ring, said piston device being mounted on the pull rod by a split ring retainer situated in one groove and extending into an interior groove in the adaptor and a resilient split ring retained in another groove and positioned to engage the piston device and to retain the seal on its adaptor.

  1. 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.

  2. Pull rod assembly

    SciTech Connect

    Cioletti, O.C.

    1990-05-22

    This patent describes a pull rod assembly. It comprises: a pull rod having three peripheral grooves, a piston device including an adaptor ring and a seal ring. The piston device is mounted on the pull rod by a split ring retainer situated in one groove and extending into an interior groove in the adaptor and a resilient split ring retained in another groove and positioned to engage the piston device and to retain the seal on its adaptor.

  3. 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.

  4. High-throughput rod-induced electrospinning

    NASA Astrophysics Data System (ADS)

    Wu, Dezhi; Xiao, Zhiming; Teh, Kwok Siong; Han, Zhibin; Luo, Guoxi; Shi, Chuan; Sun, Daoheng; Zhao, Jinbao; Lin, Liwei

    2016-09-01

    A high throughput electrospinning process, directly from flat polymer solution surfaces induced by a moving insulating rod, has been proposed and demonstrated. Different rods made of either phenolic resin or paper with a diameter of 1–3 cm and a resistance of about 100–500 MΩ, has been successfully utilized in the process. The rod is placed approximately 10 mm above the flat polymer solution surface with a moving speed of 0.005–0.4 m s‑1 this causes the solution to generate multiple liquid jets under an applied voltage of 15–60 kV for the tip-less electrospinning process. The local electric field induced by the rod can boost electrohydrodynamic instability in order to generate Taylor cones and liquid jets. Experimentally, it is found that a large rod diameter and a small solution-to-rod distance can enhance the local electrical field to reduce the magnitude of the applied voltage. In the prototype setup with poly (ethylene oxide) polymer solution, an area of 5 cm  ×  10 cm and under an applied voltage of 60 kV, the maximum throughput of nanofibers is recorded to be approximately144 g m‑2 h‑1.

  5. High-throughput rod-induced electrospinning

    NASA Astrophysics Data System (ADS)

    Wu, Dezhi; Xiao, Zhiming; Teh, Kwok Siong; Han, Zhibin; Luo, Guoxi; Shi, Chuan; Sun, Daoheng; Zhao, Jinbao; Lin, Liwei

    2016-09-01

    A high throughput electrospinning process, directly from flat polymer solution surfaces induced by a moving insulating rod, has been proposed and demonstrated. Different rods made of either phenolic resin or paper with a diameter of 1-3 cm and a resistance of about 100-500 MΩ, has been successfully utilized in the process. The rod is placed approximately 10 mm above the flat polymer solution surface with a moving speed of 0.005-0.4 m s-1 this causes the solution to generate multiple liquid jets under an applied voltage of 15-60 kV for the tip-less electrospinning process. The local electric field induced by the rod can boost electrohydrodynamic instability in order to generate Taylor cones and liquid jets. Experimentally, it is found that a large rod diameter and a small solution-to-rod distance can enhance the local electrical field to reduce the magnitude of the applied voltage. In the prototype setup with poly (ethylene oxide) polymer solution, an area of 5 cm  ×  10 cm and under an applied voltage of 60 kV, the maximum throughput of nanofibers is recorded to be approximately144 g m-2 h-1.

  6. Rod sequence advisor

    SciTech Connect

    Wood, R.M. ); Lu, Yi ); Furia, R.V.; Thompson, R.J. ); Lin, Ching-lu )

    1992-01-01

    During startup and power shaping maneuvers of boiling water reactors (BWR's), control rods are sequentially withdrawn from the reactor core. The withdrawal sequences determine the overall reactor power and the local core power density and are based on the knowledge of station engineers. It is important that the control rods are withdrawn in such a manner that the local power level does not become excessive while the desired reactor power is generated. Rules that constrain the relative positions of control rod groups have been developed to do this. While these rules are relatively simple, applying them to all possible movements of the 17 control rod groups in a typical BWR is complex and time consuming. SMARTRODS, is a rule based pilot expert system, was developed in LISP for the determination of the rod sequences.

  7. Rod Photoreceptors Detect Rapid Flicker

    ERIC Educational Resources Information Center

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

    1977-01-01

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

  8. Properties of a gold-deposited surface plasmon resonance-based glass rod sensor with various light-emitting diodes and its application to a refractometer

    NASA Astrophysics Data System (ADS)

    Mitsushio, Masaru; Higo, Morihide

    2012-08-01

    The performance of a simple sensor system prepared using gold (Au)-deposited glass rods of 1 to 4 mm in diameter with a deposition length of 100 mm based on surface plasmon resonance (SPR) is presented. The sensor properties of the Au-deposited glass rods of 2 mm in diameter with deposition lengths of 10 to 100 mm are also presented. The sensor system consists of a light-emitting diode (LED) as the light source and a photodiode (PD) as the detector. The response curves and sensor properties of the Au-deposited glass rod with a Au film thickness of 45 nm obtained by using three LEDs with yellowish green (563 nm), red (660 nm), and infrared (940 nm) emissions were investigated. The results were compared with those of a corresponding Au-deposited optical fiber sensor with a core diameter of 0.2 mm. Though the sensitivity, response, and detection limit of the Au-deposited glass rod sensor are lower than those of the optical fiber sensor, the fabrication and handling of the Au-deposited glass rod sensor are easier because of the robustness. Since the dielectric constant of Au changes with the light wavelength, the sensor properties of both the Au-deposited glass rod sensor and the optical fiber sensor depend strongly on the wavelength of the incident light and can be controlled by changing the LED emission wavelength. This sensor system is a new SPR-based refractometer with easy construction and operation. Ethanol concentrations in various spirits were measured with this SPR-based refractometer and the results agreed well with those measured with an Abbe refractometer.

  9. Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

    PubMed Central

    Merkel, Roswitha; Müller, Peter

    2015-01-01

    Summary We developed a new type of molecular rods consisting of two (or more) rigid units linked by a flexible joint. Consequently we called these constructs articulated rods (ARs). The syntheses of ARs were carried out by a flexible and modular approach providing access to a number of compounds with various functionalizations in terminal positions. First applications were presented with pyrene, cinnamoyl and anthracenyl labelled ARs. PMID:25670995

  10. Calcium spikes in toad rods.

    PubMed Central

    Fain, G L; Gerschenfeld, H M; Quandt, F N

    1980-01-01

    1. When the retina of the toad, Bufo marinus, was superfused with 6-12 mM-tetraethylammonium chloride (TEA), intracellular recordings from rods showed large, depolarizing regenerative potentials. For brief exposures to TEA, these potentials occurred during the recovery phase of the light responses; whereas, during longer exposures, they were spontaneous in darkness but suppressed during illumination. Similar regenerative potentials were observed during perfusion with 3-10 mM-4-aminopyridine and 1-2 mM-BaCl2. 2. The amplitude of the regenerative potentials depended upon the extracellular Ca concentration ([Ca2+]o). Lowering [Ca2+]o decreased their amplitude and in zero [Ca2+]o they were reversibly abolished. Increasing [Ca2+]o by 1.5-2 times produced a small hyperpolarization of membrane potential and a large augmentation in regenerative response amplitude. However, larger increases in [Ca2+]o produced large membrane hyperpolarizations and reversibly suppressed the regenerative responses. 3. High concentrations of Sr2+ in TEA also enhanced regenerative activity but did not affect the rod resting membrane potential. The amplitude of regenerative potentials increased continuously with increasing [Sr2+]o, and in 28 mM-Sr2+ the rods generated 60-70 mV action potentials, even in the absence of extracellular Na+. 4. The regenerative potentials were blocked by 25 microM-Cd2+, 50-100 microM-Co2+, 5mM-Mg2+, and 100 microM-D-600. They were unaffected by 2 microM-TTX or 2-5 mM-Na aspartate. 5. In Ringer containing 12 mM-TEA, large anode break responses could be recorded from rods at the termination of inward current pulses. These anode break responses were also suppressed by Co2+ and unaffected by TTX or Na aspartate. 6. We conclude that the membrane of toad rods contains a conductance normally selective for Ca2+, which is activated by depolarization. In normal Ringer, the inward current through this conductance produces little effect, since it is balanced by a large outward

  11. 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.

  12. Why rods and cones?

    PubMed

    Lamb, T D

    2016-02-01

    Under twenty-first-century metropolitan conditions, almost all of our vision is mediated by cones and the photopic system, yet cones make up barely 5% of our retinal photoreceptors. This paper looks at reasons why we additionally possess rods and a scotopic system, and asks why rods comprise 95% of our retinal photoreceptors. It considers the ability of rods to reliably signal the arrival of individual photons of light, as well as the ability of the retina to process these single-photon signals, and it discusses the advantages that accrue. Drawbacks in the arrangement, including the very slow dark adaptation of scotopic vision, are also considered. Finally, the timing of the evolution of cone and rod photoreceptors, the retina, and the camera-style eye is summarised.

  13. Compact, mission configurable mm-wave spectrometer based on a channel drop filter

    NASA Astrophysics Data System (ADS)

    Smirnova, Evgenya I.; Bailey, Aimee G.; Earley, Lawrence M.; Kurennoy, Sergey S.

    2007-04-01

    We have developed a novel mm-wave spectrometer based on a Photonic Band Gap (PBG) channel-drop filter (CDF). There is a need for a compact wide-band versatile and configurable mm-wave spectrometer for applications in mm-wave communications and remote sensing. CDFs present us with a unique means for filtering frequencies at mm-waves. CDF is a novel concept allowing filtering the frequency spectra and channeling selected frequencies into separate waveguides through a PBG structure. We have designed a spectrometer with a CDF working in the frequency range of 90-130 GHz. The CDF can be connected to any type of antenna and detector. A large ground based outdoor antenna can be used for remote sensing with radars. A compact antenna can be used for indoor or space applications. The signal in the waveguide channels can be measured with any type of sensor such as a cooled bolometer or a room temperature mm-wave diode. The size of the spectrometer is under 5 inches by 5 inches and just a quarter of an inch in thick. Multiple filters can be stacked together to construct a mission specific package. We propose to construct the filter with silicon rods on a 100mm silicon wafer using MEMS technology. We will then evaluate the filter at our mm-wave laboratory to demonstrate the channeling of frequencies in a proof-of-principle experiment at 100GHz. This technology will work well for frequencies from 60GHz to 1000GHz.

  14. On the theory of thin and thin-walled rods

    NASA Technical Reports Server (NTRS)

    Dzhanelidze, G Y

    1951-01-01

    Through the work of V. Z. Vlasov a theory of thin-walled rods has been established that is widely applicable in practice. This theory was extended by A. A. Umanski to thin-walled rods of closed profile section. The authors based their work on the concepts of the modern theory of shells. An attempt is made herein to construct a theory of thin-walled rods including the classical theory of deformation of thin rods by making use of a kinematic assumption.

  15. Flexible sucker rod unit

    SciTech Connect

    Allen, L.F.

    1987-02-03

    This patent describes a deep well having: a. an education tube with an inside diameter extending from the surface of the earth to far below the surface, b. a reciprocating pump housing attached to the bottom of the education tube, c. pump jack means at the surface for reciprocating the pump, d. a light sucker rod connected to the pump jack means and extending into the education tube, and e. a series of heavy sinker bars having a large cross sectional area in the education tube connecting the light sucker rod to the pump; f. an improved integral metal flexible rod unit interconnecting the sinker bars comprising in combination with the above: g. a coupling on each end of the integral metal flexible rod unit connecting the flexible rod unit to the contiguous sinker bar, h. a segment which is flexible as compared to the sinker bars connecting one of the couplings to i. an integral metal bearing adjacent to the other of the couplings, the bearing having j. a cylindrical surface with k. a diameter i. only slightly smaller than the inside diameter of the education tube thereby forming a sliding fit therewith, and ii. greater than the diameter of any other portion of the flexible rod unit and the sinker bar, and l. grooves in the cylindrical surface for the passage of fluid between in the education tube around the bearing.

  16. Polished rod liner puller assmbly

    SciTech Connect

    Baxter, B.V.

    1990-01-02

    This patent describes a polished rod liner puller assembly operable with a well casing head assembly to remove a polished rod liner member of a polished rod liner assembly from a well. It comprises: a work table assembly operable to be placed around the well casing head assembly and enclose the polished rod liner assembly; a base plate assembly mounted on the work table assembly; a piston and cylinder jack assembly mounted on the base plate assembly and extended upwardly therefrom; and a winged rod clamp assembly connectable to the piston and cylinder jack assembly and to a polished rod member of the polished rod liner assembly and operable on actuation of the piston and cylinder jack assembly to axially move the polished rod member and the polished rod liner member to remove the polished rod liner member from the well.

  17. Nonlinearity and noise at the rod - rod bipolar cell synapse

    PubMed Central

    Trexler, E. Brady; Casti, Alexander R.R.; Zhang, Yu

    2010-01-01

    In the retina, rod bipolar (RBP) cells synapse with many rods, and suppression of rod outer segment and synaptic noise is necessary for their detection of rod single photon responses (SPRs). Depending on the rods’ signal to noise ratio (SNR), the suppression mechanism will likely eliminate some SPRs as well, resulting in decreased quantum efficiency. We examined this synapse in rabbit, where 100 rods converge onto each RBP. Suction electrode recordings showed that rabbit rod SPRs were difficult to distinguish from noise (independent SNR estimates were 2.3 and 2.8). Nonlinear transmission from rods to RBPs improved response detection (SNR = 8.7), but a large portion of the rod SPRs were discarded. For the dimmest flashes, the loss approached 90%. Despite the high rejection ratio, noise of two distinct types were apparent in the RBP traces: low amplitude rumblings and discrete events that resembled the SPR. The SPR-like event frequency suggests they result from thermal isomerizations of rhodopsin, which occured at the rate 0.033 s−1rod−1. The presence of low amplitude noise is explained by a sigmoidal input-output relationship at the rod - RBP synapse and the input of noisy rods. The rabbit rod SNR and RBP quantum efficiency are the lowest yet reported, suggesting that the quantum efficiency of the rod - RBP synapse may depend on the SNR in rods. These results point to the possibility that fewer photoisomerizations are discarded for species such as primate, which has a higher rod SNR. PMID:21047445

  18. Understanding flame rods

    SciTech Connect

    McAuley, J.A. Jr.

    1995-11-01

    The flame rod is probably the least understood method of flame detection. Although it is not recommended for oilfired equipment, it is very common on atmospheric, or {open_quotes}in-shot,{close_quotes} gas burners. It is also possible, although not common, to have an application with a constant gas pilot, monitored by a flame rod, and maintaining an oil main flame. Regardless of the application, chances are that flame rods will be encountered during the course of servicing. The technician today must be versatile and able to work on many different types of equipment. One must understand the basic principles of flame rods, and how to correct potential problems. The purpose of a flame detection system is two-fold: (1) to prove there is no flame when there shouldn`t be one, and (2) to prove there is a flame when there should be one. Flame failure response time is very important. This is the amount of time it takes to realize there is a loss of flame, two to four seconds is typical today. Prior to flame rods, either bi-metal or thermocouple type flame detectors were common. The response time for these detectors was up to three minutes, seldom less than one minute.

  19. 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

  20. Welded oil well pump rod

    SciTech Connect

    Hughes, R.F.

    1986-06-10

    A friction welded multiple component oil well sucker rod is described which consists of an elongated cylindrical rod section and apposed coupling end portions welded to opposite ends of the rod section, the coupling end portions being of a nominal maximum diameter at least 1.5 times greater than the rod section and including means for connecting the sucker rod to an adjacent rod in end to end relationship. The couplings end portions each include an axial tapered portion between the connecting means and an end face adapted to be butted to the rod section, the coupling end portions being butted against the opposed end portions of the rod section during a friction welding operation to form a radially outward projecting bulge of displaced material on the rod section and the coupling end portions, respectively. A greater cross-sectional area is formed at the transition of the rod section to the coupling end portion to reduce the unit tensile stress on the sucker rod in the vicinity of the weld, wherein the displaced material is machined to form a tapered surface between the rod section and the axial tapered portion of the coupling end portion, the tapered surface having an angle of taper with respect to the longitudinal axis of the sucker rod less than the angle of taper of the coupling end portion.

  1. Magnetic screw rod using dual state 0.6C-13Cr-Fe bulk magnetic material

    NASA Astrophysics Data System (ADS)

    Mita, Masahiro; Hirao, Noriyoshi; Kimura, Fumio

    2002-05-01

    A magnetic screw rod that can replace a mechanical ball screw has been successfully fabricated. This type of device provides linear motion from a rotating motor. The magnetic screw rod is made from dual state 0.6C-13Cr-Fe bulk magnetic rod stock. The material, originally soft magnetically, can be heat treated to obtain a nonmagnetic region which substitutes for the groove of a conventional magnetic screw rod. This method produces a magnetic screw rod with a smooth, round outer shape and a longer, cleaner operational life. This experiment successfully yielded a 300 mm long, 25 mm diameter magnetic rod with 10 mm pitch, 4 mm width, 4 mm depth spiral nonmagnetic region.

  2. Rod pumping optimization program reduces equipment failures and operating costs

    SciTech Connect

    Allen, L.F.; Svinos, J.G.

    1984-09-01

    In 1975, an intensive program was initiated by Gulf Oil EandP Central Area to reduce rod and tubing failure rates in the fields of the northwest corner of Crane County, Texas. Chronologically the program steps were: The replacement of rod strings experiencing three failures in three months. The replacement of tubing strings experiencing two failures in three months. The use of inspected, classified and plastic coated new or used grade ''C'' rods. The use of inspected, classified and internally plastic coated used or new tubing. The exclusive use of high working stress rods. The exclusive use of specially designed fiberglass sucker rod systems with improved sinker bar design. This program reduced rod failure rates from 16% to 4% and tubing failures from 7% to 3% per month. The lighter rod design reduced lifting costs by $2 MM per year on 880 active wells. Of the 219 wells equipped with fiberglass sucker rods in the last two years, there have been no operational body breaks or tubing leaks.

  3. Class D sucker rods

    SciTech Connect

    Woodings, R. T.

    1984-10-23

    It has been found that API Class D sucker rods can be made inexpensively from low-alloy, low-cost steel by following a suitable induction-normalizing process and using a suitable steel to which there has been added 0.07 to 0.15 percent of vanadium.

  4. 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)

  5. 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)

  6. 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.

  7. Sucker rod centralizer

    SciTech Connect

    Rivas, O.; Newski, A.

    1989-10-03

    This patent describes a device for centralizing at least one sucker rod within a production pipe downhole in a well and for reducing frictional forces between the pipe and at least one sucker rod. It comprises an elongate, substantially cylindrical body member having a longitudinal axis, a plurality of slots within the member and a rotatable member mounted within each slot, each of the plurality of slots has its major dimension along a first axis parallel to the longitudinal axis of the body member and is oriented with respect to the other seats so as to form a helicoidal array for maximizing the total surface contact area between the rotatable members and the pipe and for decreasing the forces acting on each rotatable member.

  8. Sucker rod guide

    SciTech Connect

    White, R.C.

    1988-10-25

    This patent describes an improved guide for use in a string of sucker rods for reciprocation in a tubing string in a borehole, the sucker rods having threaded male ends, the guide comprising: an elongated upright cylindrical member of external diameter less than the internal diameter of tubing in which it is to be used, the member having sucker rod receiving female threaded openings at the upper and lower ends, the threaded openings being coaxial of the member cylindrical axis whereby the member may be positioned in a string of sucker rods, and including a plurality of spaced-apart parallel sided slots within the member, each slot being of semi-circular configuration and of depth greater than the radius and less than the diameter of the cylindrical member, the sidewalls of each slot being parallel to and equally spaced from a plane of the member cylindrical axis; the member having an axle bore therein for each of the slots, the axle bores being parallel and spaced apart from each other, a plane of the axis of each bore being perpendicular the member cylindrical axis and the axis of each bore being displaced away from the member cylindrical axis; an axle received in each axle bore; and a wheel received on each axle the diameter of each wheel being approximately the diameter of the cylindrical member, the periphery of each wheel extending beyond the member cylindrical wall whereby the wheels are positioned to engage and roll on the internal cylindrical surface of tubing, the planes of adjacent slots in the member being rotationally displaced from each other, a portion of each wheel extending beyond the cylindrical surface of the member, the opposed portion of each wheel being within the confines of the member cylindrical surface whereby each wheel can contact a tubing wall at only one point on its cylindrical surface.

  9. APPARATUS FOR SHEATHING RODS

    DOEpatents

    Ford, W.K.; Wyatt, M.; Plail, S.

    1961-08-01

    An arrangement is described for sealing a solid body of nuclear fuel, such as a uranium metal rod, into a closelyfitting thin metallic sheath with an internal atmosphere of inert gas. The sheathing process consists of subjecting the sheath, loaded with the nuclear fuel body, to the sequential operations of evacuation, gas-filling, drawing (to entrap inert gas and secure close contact between sheath and body), and sealing. (AEC)

  10. Sucker rod coupling

    SciTech Connect

    Klyne, A.A.

    1986-11-11

    An anti-friction sucker rod coupling is described for connecting a pair of sucker rods and centralizing them in a tubing string, comprising: an elongate, rigid, substantially cylindrical body member, each end of the body member forming means for threadably connecting the body member with a sucker rod. The body member further forms a transversely extending, substantially diametric, generally vertical slot extending therethrough. The body member further forms a pin bore, such pin bore extending transversely through the body member so as to intersect the slot substantially perpendicularly; a wheel member positioned within the slot to rotate in a generally vertical plane. The wheel member has a portion thereof extending beyond the periphery of the body member to engage the inner surface of the tubing string and centralize the coupling; and a pin mounted in the pin bore and supporting member thereon, whereby the wheel member is rotatable within the slot; the wheel member having sufficient clearance between its side surfaces and the wall surfaces of the slot, when the wheel member is centered in the slot on the pin, whereby the wheel member may shift along the pin to assist in ejecting sand and oil from the slot.

  11. 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.

  12. 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.

  13. Rod locking device

    SciTech Connect

    Troxell, J.N. Jr.

    1986-07-22

    A ram locking apparatus used on a blowout preventer is described having a housing, a ram, ram actuating means having a closing side and a retracted side and a tail rod having its inner end connected to the ram actuating means and its outer end engaged by the apparatus to lock the ram. The apparatus consists of: a lock housing having a closed end and a hollow interior connected to the exterior of the preventer housing in which the tail rod is positioned, a body positioned within the lock housing, a primary piston, a lost motion connection between the primary piston and the body, a lock piston associated with the primary piston and movable axially with respect to the primary piston, a tapered split locking ring interconnected to the lock piston, wedging means with the split locking ring, and means for supplying fluid under pressure into the lock housing for movement of the pistons, the initial pressure on the primary pistons causing movement of the body to engage the ram tail rod and subsequently moving the lock piston relative to the wedging means and to thereby wedge the split locking ring against the interior of the lock housing to lock the body therein against movement in the lock housing.

  14. OpenMM accelerated MMTK

    NASA Astrophysics Data System (ADS)

    Bishop, Kevin P.; Constable, Steve; Faruk, Nabil F.; Roy, Pierre-Nicholas

    2015-06-01

    In this work, we provide an interface developed to link the Molecular Modelling toolkit (MMTK) with OpenMM in order to take advantage of the fast evaluation techniques of OpenMM. This interface allows MMTK scripts using the Langevin dynamics integrator, for both classical and path integral simulations, to be executed on a variety of hardware including graphical processing units via OpenMM. The interface has been developed using Python and Cython to take advantage of the high level abstraction thanks to the MMTK and OpenMM software packages. We have tested the interface on a number of systems to observe which systems benefit most from the acceleration libraries of OpenMM.

  15. SSC 40 mm cable results and 50 mm design discussions

    SciTech Connect

    Christopherson, D.; Capone, D.; Hannaford, R.; Remsbottom, R.; Jayakumar, R.; Snitchler, G. ); Scanlan, R.; Royet, J. )

    1990-09-01

    A summary of the cable produced for the 1990 40 mm Dipole Program is presented. The cable design parameters for the 50 mm Dipole Program are discussed, as well as portions of the SSC specification draft. Considerations leading to the final cable configuration and the results of preliminary trials are included. The first iteration of a strand mapping program to automate cable strand maps is introduced. 7 refs., 2 figs., 1 tab.

  16. The Role of Stimulus-Size on Performance in the Embedded-Figures-Test and in the Rod-and-Frame-Test and the Implications of This Role for the Perceptual and Cognitive Style Constructs in Educational Technology Research.

    ERIC Educational Resources Information Center

    Streibel, Michael J.

    Three experiments were performed in which subjects were exposed to two sizes of the Embedded Figures Test (EFT), and subjects in the third experiment were also exposed to two sizes of the Rod and Frame Test (RFT). In the first experiment, where the EFT had a size differential of 1 to 4, a nonsignificant size effect and a significant rank…

  17. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

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

  18. Cone rod dystrophies.

    PubMed

    Hamel, Christian P

    2007-01-01

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

  19. 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.

  20. Reactor control rod timing system

    SciTech Connect

    Wu, P.T.

    1982-02-09

    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.

  1. Taylor impact of glass rods

    NASA Astrophysics Data System (ADS)

    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 10GPa, respectively. High-speed photography and piezoresistive gauges were used to measure the failure front velocities in both glasses, and for impact pressures below ˜2GPa the failure front velocity increases rapidly with increasing pressure. As the pressure was increased above ˜3GPa, the failure front velocities asymptotically approached maximum values between the longitudinal and shear wave velocities of each material; at ˜4GPa, the average failure front velocities were 4.7±0.5 and 4.6±0.5mmμs-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.

  2. 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.

  3. 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.

  4. 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.

  5. Sucker rod assembly and method

    SciTech Connect

    Pagan, A.J.

    1986-07-01

    An improved sucker rod assembly is described comprising, in combination: a. a sucker rod; and b. a pair of fittings secured to opposite ends of the rod, each fitting including: i. a rigid elongated casing having interior surfaces defining an open front end and cavity extending rearwardly from the open front end in which cavity one end of the sucker rod is disposed, the side portions of the interior surfaces being contoured to define, with the side portions of the sucker rod end a single, annular elongated tapered wedge-shaped space; and ii. anchoring means filling the space and bonding to the side portions of the rod end to lock the rod end in place, the anchoring means having a narrower diameter at the front end thereof than at about the rear end thereof and being generally frusto-conical, the anchoring means comprising a plurality of separate rigid inserts, the interior surfaces of which collectively define a central elongated passageway in which the rod end is received, the interior surfaces of the inserts being tightly bonded to the side portions of the rod, and the inserts being bonded to each other along the contact lines therebetween to form a unitary structure.

  6. 13. VIEW OF UNDERSIDE OF BRIDGE, SHOWING TENSION RODS, SWAY ...

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

    13. VIEW OF UNDERSIDE OF BRIDGE, SHOWING TENSION RODS, SWAY BRACING TIMBER STRINGERS CARRYING CORRUGATED METAL DECK. LOOKING NORTH-NORTHWEST. 65mm lens - Tule River Hydroelectric Complex, Tule River Bridge, Spanning North Fork of Middle Fork of Tule River, Springville, Tulare County, CA

  7. Efficient wide-aperture neodymium glass rod amplifiers

    SciTech Connect

    Potemkin, A K; Zhurin, K A; Kirsanov, A V; Kopelovich, E A; Kuznetsov, M V; Kuz'min, A A; Flat, F A; Khazanov, Efim A; Shaikin, A A

    2011-06-30

    Amplifiers based on neodymium phosphate glass rods 60 - 100 mm in diameter are experimentally studied. The amplifiers are pumped by INP-16/250 tubular flash lamps placed in a universal pump cavity with a two-section mirror reflector. A compact high-voltage capacitive energy storage with a preionisation circuit was developed to supply the lamps. (lasers)

  8. The GBT 4mm Receiver

    NASA Astrophysics Data System (ADS)

    Frayer, David T.; White, S.; Watts, G.; Stennes, M.; Maddalena, R. J.; Simon, R.; Pospieszalski, M.; Bryerton, E.

    2013-01-01

    The new 4mm receiver (67--93 GHz) for the Robert C. Byrd Green Bank Telescope (GBT) was built to take advantage of the improved surface accuracy of the dish. The low frequency end of the 3mm atmospheric window is not available with ALMA (<84 GHz), and the sensitivity of the GBT is better than any other facility within this band. We discuss the design and performance of this new receiver for the GBT, and highlight the science opportunities available with the instrument. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  9. Rod Climbing of Suspensions

    NASA Astrophysics Data System (ADS)

    Guo, Youjing; Wang, Xiaorong

    We wish to report an unexpected effect observed for particle suspensions sucked to pass through a vertical pipe. Above a critical concentration, the suspension on the outside of the pipe may climb along the outside wall of the pipe and then display a surprising rod-climbing effect. Our study shows that the phenomenon is influenced mainly by the suspension composition, the pipe dimension and the suction speed. The effects of the pipe materials of different kinds are negligible. Increasing the suction force and the concentration increases the climbing height. Increasing the pipe diameter and wall thickness reduces the climbing effect. This behavior may be relevant to that the suspensions of the type described are all displaying markedly shear-thickening.

  10. 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.

  11. Binding of Ca2+ to Glutamic Acid-Rich Polypeptides from the Rod Outer Segment

    PubMed Central

    Haber-Pohlmeier, S.; Abarca-Heidemann, K.; Körschen, H. G.; Dhiman, H. Kaur; Heberle, J.; Schwalbe, H.; Klein-Seetharaman, J.; Kaupp, U. B.; Pohlmeier, A.

    2007-01-01

    Rod photoreceptors contain three different glutamic acid-rich proteins (GARPs) that have been proposed to control the propagation of Ca2+ from the site of its entry at the cyclic nucleotide-gated channel to the cytosol of the outer segment. We tested this hypothesis by measuring the binding of Ca2+ to the following five constructs related to GARPs of rod photoreceptors: a 32-mer peptide containing 22 carboxylate groups, polyglutamic acid, a recombinant segment comprising 73 carboxylate groups (GLU), GARP1, and GARP2. Ca2+ binding was investigated by means of a Ca2+-sensitive electrode. In all cases, Ca2+ binds with low affinity; the half-maximum binding constant K1/2 ranges from 6 to 16 mM. The binding stoichiometry between Ca2+ ions and carboxylic groups is ∼1:1; an exception is GARP2, where a binding stoichiometry of ∼1:2 was found. Hydrodynamic radii of 1.6, 2.8, 3.3, 5.7, and 6.7 nm were determined by dynamic light scattering for the 32-mer, polyglutamic acid, GLU, GARP2, and GARP1 constructs, respectively. These results suggest that the peptides as well as GARP1 and GARP2 do not adopt compact globular structures. We conclude that the structures should be regarded as loose coils with low-affinity, high-capacity Ca2+ binding. PMID:17218469

  12. DESIGN OF WIRE-WRAPPED ROD BUNDLE MATCHED INDEX-OF-REFRACTION EXPERIMENTS

    SciTech Connect

    Hugh McIlroy; Hongbin Zhang; Kurt Hamman

    2008-05-01

    Experiments will be conducted in the Idaho National Laboratory (INL) Matched Index-of-Refraction (MIR) Flow Facility [1] to characterize the three-dimensional velocity and turbulence fields in a wire-wrapped rod bundle typically employed in liquid-metal cooled fast reactors and to provide benchmark data for computer code validation. Sodium cooled fast reactors are under consideration for use in the U.S. Department of Energy (DOE) Global Nuclear Energy Partnership (GNEP) program. The experiment model will be constructed of quartz components and the working fluid will be mineral oil. Accurate temperature control (to within 0.05 oC) matches the index-of-refraction of mineral oil with that of quartz and renders the model transparent to the wavelength of laser light employed for optical measurements. The model will be a scaled 7-pin rod bundle enclosed in a hexagonal canister. Flow field measurements will be obtained with a LaVision 3-D particle image velocimeter (PIV) and complimented by near-wall velocity measurements obtained from a 2-D laser Doppler velocimeter (LDV). These measurements will be used as benchmark data for computational fluid dynamics (CFD) validation. The rod bundle model dimensions will be scaled up from the typical dimensions of a fast reactor fuel assembly to provide the maximum Reynolds number achievable in the MIR flow loop. A range of flows from laminar to fully-turbulent will be available with a maximum Reynolds number, based on bundle hydraulic diameter, of approximately 22,000. The fuel pins will be simulated by 85 mm diameter quartz tubes (closed on the inlet ends) and the wire-wrap will be simulated by 25 mm diameter quartz rods. The canister walls will be constructed from quartz plates. The model will be approximately 2.13 m in length. Bundle pressure losses will also be measured and the data recorded for code comparisons. The experiment design and preliminary CFD calculations, which will be used to provide qualitative hydrodynamic

  13. Fluorometer with a quartz-rod waveguide-integrating sphere configuration to measure evanescent-field luminescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A fluorometer was designed to measure evanescent-field luminescence. A quartz-rod waveguide (d = 2 mm) was installed coaxally inside a cylindrical flow-through cell (id = 2.3 mm, od = 6.3 mm, l = 116 mm). An excitation beam from a UV LED or a miniature xenon flashlamp was focused by a ball lens and ...

  14. Apollo 12 photography 70 mm, 16 mm, and 35 mm frame index

    NASA Technical Reports Server (NTRS)

    1970-01-01

    For each 70-mm frame, the index presents information on: (1) the focal length of the camera, (2) the photo scale at the principal point of the frame, (3) the selenographic coordinates at the principal point of the frame, (4) the percentage of forward overlap of the frame, (5) the sun angle (medium, low, high), (6) the quality of the photography, (7) the approximate tilt (minimum and maximum) of the camera, and (8) the direction of tilt. A brief description of each frame is also included. The index to the 16-mm sequence photography includes information concerning the approximate surface coverage of the photographic sequence and a brief description of the principal features shown. A column of remarks is included to indicate: (1) if the sequence is plotted on the photographic index map and (2) the quality of the photography. The pictures taken using the lunar surface closeup stereoscopic camera (35 mm) are also described in this same index format.

  15. Comparison of hinged and contoured rods for occipitocervical arthrodesis in adults: A clinical study

    PubMed Central

    Abode-Iyamah, Kingsley O; Dlouhy, Brian J; Lopez, Alejandro J; Menezes, Arnold H; Hitchon, Patrick W; Dahdaleh, Nader S

    2016-01-01

    Introduction: A rigid construct that employs an occipital plate and upper cervical screws and rods is the current standard treatment for craniovertebral junction (CVJ) instability. A rod is contoured to accommodate the occipitocervical angle. Fatigue failure has been associated these acute bends. Hinged rod systems have been developed to obviate intraoperative rod contouring. Object: The aim of this study is to determine the safety and efficacy of the hinged rod system in occipitocervical fusion. Materials and Methods: This study retrospectively evaluated 39 patients who underwent occipitocervical arthrodesis. Twenty patients were treated with hinged rods versus 19 with contoured rods. Clinical and radiographic data were compared and analyzed. Results: Preoperative and postoperative Nurick and Frankel scores were similar between both groups. The use of allograft, autograft or bone morphogenetic protein was similar in both groups. The average number of levels fused was 4.1 (±2.4) and 3.4 (±2) for hinged and contoured rods, respectively. The operative time, estimated blood loss, and length of stay were similar between both groups. The occiput to C2 angle was similarly maintained in both groups and all patients demonstrated no movement across the CVJ on flexion-extension X-rays during their last follow-up. The average follow-up for the hinged and contoured rod groups was 12.2 months and 15.9 months, respectively. Conclusion: Hinged rods provide a safe and effective alternative to contoured rods during occipitocervical arthrodesis.

  16. Comparison of hinged and contoured rods for occipitocervical arthrodesis in adults: A clinical study

    PubMed Central

    Abode-Iyamah, Kingsley O; Dlouhy, Brian J; Lopez, Alejandro J; Menezes, Arnold H; Hitchon, Patrick W; Dahdaleh, Nader S

    2016-01-01

    Introduction: A rigid construct that employs an occipital plate and upper cervical screws and rods is the current standard treatment for craniovertebral junction (CVJ) instability. A rod is contoured to accommodate the occipitocervical angle. Fatigue failure has been associated these acute bends. Hinged rod systems have been developed to obviate intraoperative rod contouring. Object: The aim of this study is to determine the safety and efficacy of the hinged rod system in occipitocervical fusion. Materials and Methods: This study retrospectively evaluated 39 patients who underwent occipitocervical arthrodesis. Twenty patients were treated with hinged rods versus 19 with contoured rods. Clinical and radiographic data were compared and analyzed. Results: Preoperative and postoperative Nurick and Frankel scores were similar between both groups. The use of allograft, autograft or bone morphogenetic protein was similar in both groups. The average number of levels fused was 4.1 (±2.4) and 3.4 (±2) for hinged and contoured rods, respectively. The operative time, estimated blood loss, and length of stay were similar between both groups. The occiput to C2 angle was similarly maintained in both groups and all patients demonstrated no movement across the CVJ on flexion-extension X-rays during their last follow-up. The average follow-up for the hinged and contoured rod groups was 12.2 months and 15.9 months, respectively. Conclusion: Hinged rods provide a safe and effective alternative to contoured rods during occipitocervical arthrodesis. PMID:27630479

  17. Rewetting of hot vertical rod during jet impingement surface cooling

    NASA Astrophysics Data System (ADS)

    Agrawal, Chitranjan; Kumar, Ravi; Gupta, Akhilesh; Chatterjee, Barun

    2016-06-01

    A stainless steel (SS-316) vertical rod of 12 mm diameter at 800 ± 10 °C initial temperature was cooled by normal impinging round water jet. The surface rewetting phenomenon was investigated for a range of jet diameter 2.5-4.8 mm and jet Reynolds number 5000-24,000 using a straight tube type nozzle. The investigation were made from the stagnation point to maximum 40 mm downstream locations, simultaneously for both upside and downside directions. The cooling performance of the vertical rod was evaluated on the basis of rewetting parameters i.e. rewetting temperature, wetting delay, rewetting velocity and the maximum surface heat flux. Two separate Correlations have been proposed for the dimensionless rewetting velocity in terms of rewetting number and the maximum surface heat flux that predicts the experimental data within an error band of ±20 and ±15 % respectively.

  18. Regenerative hyperpolarization in rods.

    PubMed Central

    Werblin, F S

    1975-01-01

    1. The electrical properties of the rods in Necturus maculosus were studied at the cell body and the outer segments in dark and light under current and voltage clamp with a pair of intracellular electrodes separated by about 1 mum. 2. The membrane resistance in the dark was voltage- and time-dependent both for the cell body and the outer segment. Slight depolarizations in the cell body reduced the slope resistance from 60 to 10 M omega with a time constant of about 1 sec. Polarization in either direction, at the outer segment, when greater than about 20 mV, reduced the slope resistance from 60 to 30 M omega. The dark potential in the cell body was typically -30 to -35 m V; at the outer segment it was typically only -10 to -15 mV. 3. The light-elicited voltage response in both the cell body and the outer segment was largest with the membrane near the dark potential level. In both regions, the response was reduced when the membrane was polarized in either direction. 4. Under voltage-clamp conditions, a reversal potential for the light response near + 10 mV was measured at the outer segment. At the cell body no reversal potential for the light response was measured; there the clamping current required during the light response was almost of the same magnitude at all potential levels. 5. When the membrane at the cell body was hyperpolarized in the dark under voltage clamp, a transient outward current, typically about one-half the magnitude of the initial inward clamping current was required to maintain the membrane at the clamped potential level. This outward current transient was associated with a decrease in membrane resistance with similar time course. The transient outward current reversed and became inward when the membrane was clamped to potentials more negative than -80 mV. Thus, the transient outward current appears to involve a transient activation initiated by hyperpolarization. I is regenerative in that it is initiated by hyperpolarization and tends to

  19. Eulerian formulation of elastic rods

    NASA Astrophysics Data System (ADS)

    Huynen, Alexandre; Detournay, Emmanuel; Denoël, Vincent

    2016-06-01

    In numerous biological, medical and engineering applications, elastic rods are constrained to deform inside or around tube-like surfaces. To solve efficiently this class of problems, the equations governing the deflection of elastic rods are reformulated within the Eulerian framework of this generic tubular constraint defined as a perfectly stiff normal ringed surface. This reformulation hinges on describing the rod-deformed configuration by means of its relative position with respect to a reference curve, defined as the axis or spine curve of the constraint, and on restating the rod local equilibrium in terms of the curvilinear coordinate parametrizing this curve. Associated with a segmentation strategy, which partitions the global problem into a sequence of rod segments either in continuous contact with the constraint or free of contact (except for their extremities), this re-parametrization not only trivializes the detection of new contacts but also transforms these free boundary problems into classic two-points boundary-value problems and suppresses the isoperimetric constraints resulting from the imposition of the rod position at the extremities of each rod segment.

  20. Rod coupling for oil well sucker rods and the like

    SciTech Connect

    Bowers, R.

    1986-07-29

    A coupling is described for joining solid reciprocating sucker rods to form a rod string in a well pump or the like comprising a unitary metal sleeve having an axial threaded bore and an irregular outer surface, and a homogeneous and non-fibrous coating on the sleeve over the outer surface providing an externally substantially cylindrical coupling, the coating comprising a flexible and abrasive resistant thermoplastic hydrourethane polymer formed on the irregular outer surface of the sleeve while in the molten state.

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

    SciTech Connect

    Wilson, J.W.

    1982-12-01

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

  2. Pulling of 3 mm diameter AlSb rods by micro-pulling down method

    SciTech Connect

    Bourret-Courchesne Ph.D., Edith; Perrodin, Didier

    2009-05-14

    We designed and supplied special crucibles for AlSb material. Thermal insulation and limitation of Sb losses were our first work. The protection of the growth environment was also one of our priority to avoid any pollution of the Fibercryst {mu}PD facility. When this work was achieved, the next step was the calibration of the heating power for these new crucibles. Then, it was the definition of single crystal growth conditions that oriented our research. Following our proposal, many growths attempts were performed. We started from Al & Sb pure powder or from LBNL AlSb crystal as expected. We used different crucibles and different seeds.

  3. Rod coupling with mounted guide

    SciTech Connect

    Bair, M.L.

    1987-05-26

    This patent describes a well sucker rod string, in a well bore, the combination comprising: an axially elongated coupling section having threads at axially opposite ends thereof for coupling to and between successive sucker rods in the rod string, to transmit string loading. The section has first and second exposed surfaces adjacent an end of the section, and a third surface located between the first and second exposed surfaces; a rod guide consisting of molded plastic material extending about and bonded to the section third surface to project outwardly therefrom for engagement with the well bore during up and down stroking of the string; and one annular groove sunk in the section between the first and third surfaces, and another annular groove sunk in the section between the second and third surfaces. The depth of the one groove is less than about 15% of the radius of the section at the first surface.

  4. Rapid kinetics of endocytosis at rod photoreceptor synapses depends upon endocytic load and calcium.

    PubMed

    Cork, Karlene M; Thoreson, Wallace B

    2014-05-01

    Release from rods is triggered by the opening of L-type Ca2+ channels that lie beneath synaptic ribbons. After exocytosis, vesicles are retrieved by compensatory endocytosis. Previous work showed that endocytosis is dynamin-dependent in rods but dynamin-independent in cones. We hypothesized that fast endocytosis in rods may also differ from cones in its dependence upon the amount of Ca2+ influx and/or endocytic load. We measured exocytosis and endocytosis from membrane capacitance (C m) changes evoked by depolarizing steps in voltage clamped rods from tiger salamander retinal slices. Similar to cones, the time constant for endocytosis in rods was quite fast, averaging <200 ms. We manipulated Ca2+ influx and the amount of vesicle release by altering the duration and voltage of depolarizing steps. Unlike cones, endocytosis kinetics in rods slowed after increasing Ca2+ channel activation with longer step durations or more strongly depolarized voltage steps. Endocytosis kinetics also slowed as Ca2+ buffering was decreased by replacing BAPTA (10 or 1 mM) with the slower Ca2+ buffer EGTA (5 or 0.5 mM) in the pipette solution. These data provide further evidence that endocytosis mechanisms differ in rods and cones and suggest that endocytosis in rods is regulated by both endocytic load and local Ca2+ levels.

  5. Smart intramedullary rod for correction of pediatric bone deformity: a preliminary study.

    PubMed

    Firoozbakhsh, Keikhosrow; Moneim, Moheb S; Yi, In Sok; Umeda, Yuji; Theele, Daniel; Shahinpoor, Mohsen

    2004-07-01

    We were interested in determining if a smart intramedullary rod made of nitinol shape-memory alloy is capable of correcting deformed immature long bones. Because of limitations in our study design the process was reversed in that we examined the smart rod's ability to create a deformity rather than to correct one. Smart rods of different lengths and diameters were heat-treated to resume a radius of curvature of 30 to 110 mm. The low and high temperature phases of the smart rods were set, respectively, at 0 degrees C to 4 degrees C and 36 degrees C to 38 degrees C. The preshaped smart intramedullary rods were implanted in the cooled martensite phase in the medullary canal of the tibia in eight rabbits, where they restored their austenite form, causing a continuous bending force. On a weekly basis anteroposterior and lateral radiographs of the surgically treated tibia and the contralateral tibia were obtained for comparison. Rabbits were euthanized 6 weeks after surgery and computed tomography scans of both tibias were used for image analysis. Smart rods with a larger radius of curvature showed only minimal signs of remodeling; however, rods with a radius of curvature of 50 and 70 mm generated enough force history to create bone remodeling and deformation. The amount of bone deformation was highly magnified when unicortical corticotomy on the tension side was done. Based on this preliminary study the technology of the smart intramedullary rod may provide a valuable alternative method to correct pediatric skeletal deformities.

  6. 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)

  7. RP cone-rod degeneration.

    PubMed Central

    Heckenlively, J R

    1987-01-01

    A group of patients with progressive retinal degeneration and visual field loss, who meet the basic definition of RP were investigated to better define the relationship of the findings on the ERG with clinical characteristics such as visual field size, presence or absence of scotomata or pseudo-altitudinal defects on visual field, amount of night blindness; and presence or absence of macular or optic nerve changes. These studies suggest that cone-rod degeneration patients of the RP type go through the following stages; early, the ERG has a definite cone-rod pattern where the rod ERG is larger than the cone ERG while both are abnormal. As the disease advances, there is more of a reduction in the scotopic ERG such that both the rod and cone ERGs become nearly equal. As the disease further progresses the ERG becomes non-recordable on single-flash technique, but there is good residual rod function and the final rod threshold remains good until the visual field is reduced, typically less than 10 degrees with the IV-4 isopter. Finally with advanced disease the patient becomes night blind and generally becomes very difficult to distinguished from patients who have advanced rod-cone degeneration. While it may seem logical to find that visual field size correlates with various ERG parameters; this has not been as consistent a finding in patients with rod-cone degeneration in the author's experience. The analysis shows several new pieces of information about visual field changes in cone-rod degeneration; enlarged blind spots are seen earlier in cases which have recordable cone-rod patterns (group I), and pseudo-altitudinal changes are more likely to occur in autosomal recessive patients. Patients with macular lesions and central scotomata had larger amplitudes than patients with normal appearing maculae and no central scotomata. Patients with temporal optic atrophy had an earlier onset of symptoms and significant correlation with both photopic a- and b-waves and bright flash

  8. Porous tantalum rods for treating osteonecrosis of the femoral head.

    PubMed

    Liu, Z H; Guo, W S; Li, Z R; Cheng, L M; Zhang, Q D; Yue, D B; Shi, Z C; Wang, B L; Sun, W; Zhang, N F

    2014-10-20

    This study evaluated the outcomes of using porous tantalum rods for the treatment of osteonecrosis of the femoral head (ONFH). We performed core decompression and inserted porous tantalum implants in 149 patients (168 consecutive hips) with ONFH. Hips had large (65), medium (64), or small (39) lesions; 63 lesions were lateral, 68 were central, and 35 were medial. Conversion to total hip arthroplasty (THA) was the end point of this survey. A total of 130 cases (138 hips) were followed. The mean follow-up time was 38.46 ± 5.76 months; 43 hips (31%) were converted to or needed THA. Of the 43 hips requiring THA, 33 had large lesions, including 1 medial, 3 central, and 29 lateral lesions; 9 had medium, lateral lesions, and 1 hip had a small, lateral lesion. Bone grafting was used in 59 hips, with 3 hips failing; 40 of 79 hips without bone grafts failed. The sum distances between the tops of the rods and the lateral lesion boundaries (SDTL, mm) were measured in anteroposterior and lateral radiographs. In the failure and spared groups, the average SDTLs were 7.65 ± 2.759 and 0.83 ± 2.286 mm, respectively. The survival of porous tantalum rods used for treating early-stage ONFH was affected by the size and location of the lesion, whether or not a bone graft was used, as well as the distance between top of the rod and the lateral boundary of the lesion.

  9. 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.

  10. Stiffness Coefficients Measurement of Cylindrical Rods by Laser Ultrasonics

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Rossignol, C.; Audoin, B.

    2004-02-01

    A non-contact laser-ultrasonic technique is applied to the nondestructive measurement of the stiffness properties of cylindrical rods. Acoustic waves generated in a cylinder by a laser line source under thermoelastic regime are identified by the comparison between experiment and theory. Two stiffness coefficients c11 and c12 are determined by measuring the arrival time of the reflected longitudinal wave (LL) and that of the head wave (HW). The effects of laser beamwidth and time duration on the measurement are found by numerical simulations. For such an application, a radius of 0.3 mm appears as a minimum limit for the sample size using a laser source of 0.1 mm beamwidth and 20 ns time duration. Stiffness coefficients of three aluminum rods are experimentally measured with good accuracy.

  11. Rod guide/paraffin scraper

    SciTech Connect

    Mabry, J.F.

    1991-02-26

    This patent describes improvement in a rod guide and paraffin scraper. It comprises: a body including longitudinal ribs spaced radially and extending out from the body; having two identical halves with the body surrounding a bore to accept a sucker rod, and each of the identical halves having a locking and tightening feature using a tongue and groove concept for interfitting the halves together over the sucker rod. This improvement comprises a rod guide and paraffin scraper with two identical halves comprising; a cylindrical central body including, at each end, three longitudinal ribs radially spaced to form a triad leaving three flow channels, at each end of the body, of essentially the same size and spacing as the ribs; and an angular wedge with opposingly ramped sides at the inside end of each of the ribs for scraping and directing material into the flow channels; and a set of triangular shaped tongues that interfit with a set of triangular shaped grooves for tightening the identical halves together and over the sucker rod; and a pair of cone-shaped male locks at one end of the identical half to mate with a pair of cone-shaped female locks at the opposite end of the other identical half.

  12. Self-Assembly of Hexagonal Rod Arrays Based on Capillary Forces.

    PubMed

    Oliver; Bowden; Whitesides

    2000-04-15

    A series of well-ordered, extended mesostructures has been generated from hexagonal polyurethane rods (15x3.2 mm) by self-assembly using capillary forces. The surface of one or more sides of the rods was rendered hydrophilic by exposure to an oxygen plasma. This modification determined the pattern of hydrophobic and hydrophilic faces; the hydrophobic sides were coated with a thin film of a hydrophobic lubricant. Agitation of the rods in an approximately isodense aqueous environment resulted in their self-assembly, in a process reflecting the action of capillary forces, into an array whose structure depends on the pattern of hydrophobic sides; capillarity also aligned the ends of the rods. We also carried out experiments in reaction chambers that restricted the motion of the rods; this restriction served to increase the size and regularity of the assemblies. Copyright 2000 Academic Press.

  13. 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

  14. Advanced gray rod control assembly

    DOEpatents

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

    2013-09-17

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

  15. Analysis of reciprocating compressor piston rod failures

    SciTech Connect

    Tripp, H.A.; Drosjack, M.J.

    1984-02-01

    This report presents the analysis of five piston rod failures which occurred on reciprocating compressors. Calculations are shown for rod stress which includes nominal rod loading sources as well as additional loads due to unusual pressure losses in the compressor valves, flexure of the rods due to misalignment, and manufacturing errors. The additional loads were incorporated on the basis of field measurements. The stress values are used with Baquin's equation to produce fatigue life curves for the rods. Based on the calculations, recommendations for modified rods were made. The calculation procedures are described in a manner which will permit their application to other reciprocating compressors.

  16. PMMA-rod-assisted temperature sensor based on a two-turn thick-microfiber resonator

    NASA Astrophysics Data System (ADS)

    Liu, Qi; Chen, Ye

    2016-01-01

    We demonstrate a simple temperature sensor based on an optical microfiber coil resonator which is wrapped on a PMMA rod and embedded in Teflon. The microfiber is thick, strong and easy to be handled, which is 4~5 μm in diameter and more than 1 cm in waist region length. The PMMA rod has a diameter of ~2 mm. The temperature sensitivity is ~80 pm/°C thanks to the large thermal expansion coefficient of PMMA.

  17. Evaluation of the Effect of Fixation Angle between Polyaxial Pedicle Screw Head and Rod on the Failure of Screw-Rod Connection.

    PubMed

    Çetin, Engin; Özkaya, Mustafa; Güler, Ümit Özgür; Acaroğlu, Emre; Demir, Teyfik

    2015-01-01

    Introduction. Polyaxial screws had been only tested according to the ASTM standards (when they were perpendicularly positioned to the rod). In this study, effects of the pedicle screws angled fixation to the rod on the mechanical properties of fixation were investigated. Materials and Method. 30 vertically fixed screws and 30 screws fixed with angle were used in the study. Screws were used in three different diameters which were 6.5 mm, 7.0 mm, and 7.5 mm, in equal numbers. Axial pull-out and flexion moment tests were performed. Test results compared with each other using appropriate statistical methods. Results. In pull-out test, vertically fixed screws, in 6.5 mm and 7.0 mm diameter, had significantly higher maximum load values than angled fixed screws with the same diameters (P < 0.01). Additionally, vertically fixed screws, in all diameters, had significantly greater stiffness according to corresponding size fixed with angle (P < 0.005). Conclusion. Fixing the pedicle screw to the rod with angle significantly decreased the pull-out stiffness in all diameters. Similarly, pedicle screw instrumentation fixed with angle decreased the minimum sagittal angle between the rod and the screw in all diameters for flexion moment test but the differences were not significant.

  18. Evaluation of the Effect of Fixation Angle between Polyaxial Pedicle Screw Head and Rod on the Failure of Screw-Rod Connection

    PubMed Central

    Çetin, Engin; Özkaya, Mustafa; Güler, Ümit Özgür; Acaroğlu, Emre

    2015-01-01

    Introduction. Polyaxial screws had been only tested according to the ASTM standards (when they were perpendicularly positioned to the rod). In this study, effects of the pedicle screws angled fixation to the rod on the mechanical properties of fixation were investigated. Materials and Method. 30 vertically fixed screws and 30 screws fixed with angle were used in the study. Screws were used in three different diameters which were 6.5 mm, 7.0 mm, and 7.5 mm, in equal numbers. Axial pull-out and flexion moment tests were performed. Test results compared with each other using appropriate statistical methods. Results. In pull-out test, vertically fixed screws, in 6.5 mm and 7.0 mm diameter, had significantly higher maximum load values than angled fixed screws with the same diameters (P < 0.01). Additionally, vertically fixed screws, in all diameters, had significantly greater stiffness according to corresponding size fixed with angle (P < 0.005). Conclusion. Fixing the pedicle screw to the rod with angle significantly decreased the pull-out stiffness in all diameters. Similarly, pedicle screw instrumentation fixed with angle decreased the minimum sagittal angle between the rod and the screw in all diameters for flexion moment test but the differences were not significant. PMID:27019578

  19. Evaluation of spinal instrumentation rod bending characteristics for in-situ contouring.

    PubMed

    Noshchenko, Andriy; Xianfeng, Yao; Armour, Grant Alan; Baldini, Todd; Patel, Vikas V; Ayers, Reed; Burger, Evalina

    2011-07-01

    Bending characteristics were studied in rods used for spinal instrumentation at in-situ contouring conditions. Five groups of five 6 mm diameter rods made from: cobalt alloy (VITALLIUM), titanium-aluminum-vanadium alloy (SDI™), β-titanium alloy (TNTZ), cold worked stainless steel (STIFF), and annealed stainless steel (MALLEABLE) were studied. The bending procedure was similar to that typically applied for in-situ contouring in the operating room and included two bending cycles: first--bending to 21-24° under load with further release of loading for 10 min, and second--bending to 34-37° at the previously bent site and release of load for 10 min. Applied load, bending stiffness, and springback effect were studied. Statistical evaluation included ANOVA, correlation and regression analysis. TNTZ and SDI™ rods showed the highest (p < 0.05) springback at both bending cycles. VITALLIUM and STIFF rods showed mild springback (p < 0.05). The least (p < 0.05) springback was observed in the MALLEABLE rods. Springback significantly correlated with the bend angle under load (p < 0.001). To reach the necessary bend angle after unloading, over bending should be 37-40% of the required angle in TNTZ and SDI™ rods, 27-30% in VITALLIUM and STIFF rods, and around 20% in MALLEABLE rods. PMID:21563305

  20. Application of fiberglass sucker rods

    SciTech Connect

    Gibbs, S.G. )

    1991-05-01

    Fiberglass sucker rods are assuming a place in artificial-lift technology. This paper briefly describes the manufacturing process and gives some design and operational hints for practical applications. It also describes some mathematical modeling modifications needed for fiberglass wave-equation design programs.

  1. Three-Rod Linear Ion Traps

    NASA Technical Reports Server (NTRS)

    Janik, Gary R.; Prestage, John D.; Maleki, Lutfollah

    1993-01-01

    Three-parallel-rod electrode structures proposed for use in linear ion traps and possibly for electrostatic levitation of macroscopic particles. Provides wider viewing angle because they confine ions in regions outside rod-electrode structures.

  2. What operators say about fiberglass sucker rods

    SciTech Connect

    Bleakley, W.B.

    1984-11-01

    This article presents the results of an informal survey of oil producing companies and one design engineering firm in the Permian Basin about the use and performance of fiberglass sucker rods in sucker rod pumps.

  3. 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.

  4. 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.

  5. Optimization of rod diameter in solid state lasers side pumped with multiple laser diode arrays

    NASA Technical Reports Server (NTRS)

    Sims, Newton, Jr.; Chamblee, Christyl M.; Barnes, Norman P.; Lockard, George E.; Cross, Patricia L.

    1992-01-01

    Results of a study to determine the optimum laser rod diameter for maximum output energy in a solid state neodymium laser transversely pumped with multiple laser diode arrays are reported here. Experiments were performed with 1.0 mm, 1.5 mm and 2.0 mm rod radii of both neodymium doped Y3Al5O12 (Nd:YAG) and La2Be2O5 (Nd:BeL) pumped with laser diode arrays having a maximum combined energy of 10.5 mJ. Equations were derived which predict the optimum rod radius and corresponding output mirror reflectivity for a given laser material and total pump energy. Predictions of the equations agreed well with the experiments for each of the laser materials which possessed significantly different laser properties from one another.

  6. The LLAMA 12 m mm/sub-mm radiotelescope in the Andes

    NASA Astrophysics Data System (ADS)

    Lepine, Jacques; Edemundo Arnal, Marcelo; de Graauw, Thijs; Abraham, Zulema; Gimenez de Castro, Guillermo; de Gouveia Dal Pino, Elisabete; Morras, Ricardo; Larrarte, Juan; Viramontes, José; Finger, Ricardo; Kooi, Jacob; Reeves, Rodrigo; Beaklini, Pedro

    2015-08-01

    LLAMA (Large Latin American Millimetric Array) is a joint Argentinean-Brazilian project of a 12m mm/sub-mm radio telescope similar to the APEX antenna, to be installed at a site at 4800 m altitude near San Antonio de Los Cobres in the Salta Province in Argentine, at 150 km from ALMA. The scientific cases for single dish and VLBI observations include black holes and accretion disks, the molecular evolution of interstellar clouds, the structure of the Galaxy, the formation of galaxies, and much more. The antenna was ordered to the company Vertex Antennentechnik in June 2014, and the construction is progressing quickly; it will be installed at the site in 2016. The radio telescope will be equipped with up to six receivers covering bands similar to those of ALMA. Cryostats with room for 3 cartridges, constructed by NAOJ (Tokyo,Japan), will be installed in each of the two Nasmyth cabins. Among the first receivers we will have an ALMA band 9 provided by NOVA (Groningen, Holland) and a band 5 from the Chalmers University (Sweden). Other receivers are still being discussed at the time of submission of this abstract,At high frequencies, VLBI observations at high frequencies could be made with ALMA, APEX and ASTE, and Northern radiotelescopes. In this way, LLAMA will be a seed for a Latin-American VLBI network.

  7. Who makes API sucker rods and couplings

    SciTech Connect

    Not Available

    1986-03-01

    This guide identifies manufacturers qualified to produce API sucker rods and related equipment, lists chemical and mechanical properties of the various types of rods and provides dimensional characteristics. In addition, similar information is given for non-API rods such as fiberglass and aluminum.

  8. 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)

  9. 21 CFR 876.4270 - Colostomy rod.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Colostomy rod. 876.4270 Section 876.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod...

  10. 21 CFR 876.4270 - Colostomy rod.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Colostomy rod. 876.4270 Section 876.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod...

  11. 21 CFR 876.4270 - Colostomy rod.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Colostomy rod. 876.4270 Section 876.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod...

  12. 21 CFR 876.4270 - Colostomy rod.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Colostomy rod. 876.4270 Section 876.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod...

  13. 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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4270 Colostomy rod. (a) Identification. A colostomy rod...

  14. Heat Transfer Enhancement By Three-Dimensional Surface Roughness Technique In Nuclear Fuel Rod Bundles

    NASA Astrophysics Data System (ADS)

    Najeeb, Umair

    This thesis experimentally investigates the enhancement of single-phase heat transfer, frictional loss and pressure drop characteristics in a Single Heater Element Loop Tester (SHELT). The heater element simulates a single fuel rod for Pressurized Nuclear reactor. In this experimental investigation, the effect of the outer surface roughness of a simulated nuclear rod bundle was studied. The outer surface of a simulated fuel rod was created with a three-dimensional (Diamond-shaped blocks) surface roughness. The angle of corrugation for each diamond was 45 degrees. The length of each side of a diamond block is 1 mm. The depth of each diamond block was 0.3 mm. The pitch of the pattern was 1.614 mm. The simulated fuel rod had an outside diameter of 9.5 mm and wall thickness of 1.5 mm and was placed in a test-section made of 38.1 mm inner diameter, wall thickness 6.35 mm aluminum pipe. The Simulated fuel rod was made of Nickel 200 and Inconel 625 materials. The fuel rod was connected to 10 KW DC power supply. The Inconel 625 material of the rod with an electrical resistance of 32.3 kO was used to generate heat inside the test-section. The heat energy dissipated from the Inconel tube due to the flow of electrical current flows into the working fluid across the rod at constant heat flux conditions. The DI water was employed as working fluid for this experimental investigation. The temperature and pressure readings for both smooth and rough regions of the fuel rod were recorded and compared later to find enhancement in heat transfer coefficient and increment in the pressure drops. Tests were conducted for Reynold's Numbers ranging from 10e4 to 10e5. Enhancement in heat transfer coefficient at all Re was recorded. The maximum heat transfer co-efficient enhancement recorded was 86% at Re = 4.18e5. It was also observed that the pressure drop and friction factor increased by 14.7% due to the increased surface roughness.

  15. Homogenization of a thin plate reinforced with periodic families of rigid rods

    SciTech Connect

    Nazarov, Sergei A; Sweers, Guido H; Slutskij, Andrey S

    2011-08-31

    The asymptotics of the solution to the elastic bending problem for a thin plate reinforced with several periodic families of closely spaced but disjoint rods are constructed and justified, the result of homogenization being substantially different from the case when the rods are welded together into a single periodic mesh. The material in the rods is assumed to be appreciably more rigid than that in the plate. An averaged fourth-order differential operator is obtained from summing the nonelliptic operators generated by each of the families of the rods. This operator is shown to be elliptic if and only if the rods from at least two families are nonparallel. As a simplified example, the paper examines a similar stationary heat conduction problem. Bibliography: 24 titles.

  16. 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.

  17. Flash X-ray radiography source based on plasma-filled rod pinch diode

    NASA Astrophysics Data System (ADS)

    Sorokin, S. A.

    2010-04-01

    Results of experiments on the formation of a high-power focused electron beam in a plasma-filled rod pinch diode driven by a high-current MIG generator (maximum voltage, 1.3 MV; impedance, 0.65 Ω) are presented. The proposed diode with a sharpened 1.5-mm-thick tungsten rod anode provides an X-ray source for flash radiography with a size of ˜1 mm, which is capable of producing a radiation dose of 2.4 rad per pulse at a distance of 1 m. The results of comparative experiments with and without plasma injection into the diode are presented.

  18. Guide for rotating sucker rods

    SciTech Connect

    Harrel, R.D.

    1986-11-04

    This patent describes an improved guide for use in a string of sucker rods rotated in a tubing string in a borehole, the sucker rods having threaded male ends, the guide comprising: an elongated upright solid cylindrical coupling body of external diameter less than the internal diameter of tubing in which it is to be used; a pair of spaced apart axle holders positioned in three recess; an axle received in each recess in the coupling body, the axis of each axle being parallel and spaced from the body longitudinal axis; a roller rotatably received on each axle, the periphery of each roller extending exteriorly of the external cylindrical surface of the coupling body; and means to retain each of the holders in the coupling body recess.

  19. Exploiting rod technology. Final report

    SciTech Connect

    1990-06-01

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

  20. The rod circuit in the rabbit retina.

    PubMed

    Vaney, D I; Young, H M; Gynther, I C

    1991-01-01

    Mammalian retinae have a well-defined neuronal pathway that serves rod vision. In rabbit retina, the different populations of interneurons in the rod pathway can be selectively labeled, either separately or in combination. The rod bipolar cells show protein kinase C immunoreactivity; the rod (AII) amacrine cells can be distinguished in nuclear-yellow labeled retina; the rod reciprocal (S1 & S2) amacrine cells accumulate serotonin; and the dopaminergic amacrine cells show tyrosine-hydroxylase immunoreactivity. Furthermore, intracellular dye injection of the microscopically identified interneurons enables whole-population and single-cell studies to be combined in the same tissue. Using this approach, we have been able to analyze systematically the neuronal architecture of the rod circuit across the rabbit retina and compare its organization with that of the rod circuit in central cat retina. In rabbit retina, the rod interneurons are not organized in a uniform neuronal module that is simply scaled up from central to peripheral retina. Moreover, peripheral fields in superior and inferior retina that have equivalent densities of each neuronal type show markedly different rod bipolar to AII amacrine convergence ratios, with the result that many more rod photoreceptors converge on an AII amacrine cell in superior retina. In rabbit retina, much of the convergence in the rod circuit occurs in the outer retina whereas, in central cat retina, it is more evenly distributed between the inner and outer retina.

  1. Tests pinpoint sucker-rod failures

    SciTech Connect

    Elshawesh, F.; Elhoud, A.; Elagdel, E.

    1997-05-26

    A detailed metallurgical examination of a 7/8-inch and a 1-inch sucker rod revealed corrosion fatigue had caused their failure. The 7 to 8-inch rod had failed after a few months of service while the 1-inch rod failed after 1 year. Both rods had been used in a sweet-oil environment. Both rods failed by corrosion fatigue because of repeated loads during operations. Pitting because of the presence of chloride ions and carbon dioxide was initiated on the rod surface, which in turn acted as a crack origin from which the fatigue crack initiated and propagated during operations. The pitting was on the external surface. These pits were large and penetrated through the rod cross-section. Fatigue cracking is initiated at the bottom of the pit where high stress concentration is expected and propagated because the rods were subjected to the alternating stresses during operation. The extent of the fatigue crack varied in the two examined rods because of the difference in the rod heat treatment and microstructure. The paper discusses fatigue failure, the visual examination, macroscopic and microscopic examinations, rod properties, and future operations.

  2. 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.

  3. Shaping of steel mold surface of lens array by electrical discharge machining with single rod electrode.

    PubMed

    Takino, Hideo; Hosaka, Takahiro

    2014-11-20

    We propose a method for fabricating a lens array mold by electrical discharge machining (EDM). In this method, the tips of rods are machined individually to form a specific surface, and then a number of the machined rods are arranged to construct an electrode for EDM. The repetition of the EDM process using the electrode enables a number of lens elements to be produced on the mold surface. The effectiveness of our proposed method is demonstrated by shaping a lens array mold made of stainless steel with 16 spherical elements, in which the EDM process with a single rod electrode is repeatedly conducted.

  4. Modeling and analysis of a contact problem for a viscoelastic rod

    NASA Astrophysics Data System (ADS)

    Bartosz, Krzysztof; Sofonea, Mircea

    2016-10-01

    We consider a nonlinear viscoelastic rod which is in contact with a foundation along its length and is in contact with an obstacle at its end. The rod is acted up by body forces and, as a result, its mechanical state evolves. Our aim in this paper is twofold. The first one is to construct an appropriate mathematical model which describes the evolution of the rod. The second one is to prove the weak solvability of the problem. To this end, we use arguments on second-order inclusions with multivalued pseudomonotone operators.

  5. Critical Power in 7-Rod Tight Lattice Bundle

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Kureta, Masatoshi; Akimoto, Hajime

    The Reduced-Moderation Water Reactor (RMWR) has recently becomes of great concern. The RMWR is expected to promote the effective utilization of uranium recourse. The RMWR is based on water-cooled reactor technology, with achieved under lower core water volume and water flow rate. In comparison with the current light water reactors whose water-to-fuel volume ratio is about 2-3, in the RMWR, this value is reduced to less than 0.5. Thereby, there is a need to research its cooling characteristics. Experimental research on critical power in tight lattice bundle that simulates the RMWR has been carried out in Japan Atomic Energy Research Institute (JAERI). The bundle consists one center rod and six peripheral rods. The 7 rods are arranged on a 14.3mm equilateral triangular pitch. Each rod is 13mm in outside diameter. An axial 12-step power distribution is employed to simulate the complicate heating condition in RMWR. Experiments are carried out under G=100-1400kg/m2s, Pex=2-8.5MPa. Effects of mass velocity, inlet temperature, pressure, radial peaking factor and axial peaking factor on critical power and critical quality are discussed. Compared with axial uniform heating condition, the axial non-uniform heating condition causes an obvious decrease in critical quality. Arai correlation, which is the only correlation that has been optimized for tight lattice condition, is verified with the present experimental data. The correlation is found to be able to give reasonable prediction only around RMWR nominal operating condition.

  6. [The architectural rods by Nikolaus Goldmanns (1611-1665)].

    PubMed

    Vollrath, Hans-Joachim

    2005-01-01

    By the end of the 19th century the Philosophical Faculty of Würzburg University had compiled a notable collection of mathematical and scientific instruments as teaching aids. Early items are attributed to KASPAR SCHOTT (1608-1666), who was professor of mathematics in Würzburg from 1655 until 1666. Most of these "old-fashioned" instruments were sold to the Bayerisches Nationalmuseum München in 1877. One of the items is a set of six brass rods in a leather-covered case of unknown meaning and of uncertain origin. This paper identifies the instrument as "Architectural rods" designed by NIKOLAUS GOLDMANN (1611-1665), a German mathematician and architect who lived in Leiden. He described the rods in his 'Tractatus de stylometris', Leiden 1662. The University library of Würzburg owns a copy of this book that belonged to the Philosophical Faculty in 1754. On the basis of this treatise the following paper analyses the use and importance of these rods for the construction of the five classical orders of columns. PMID:17153312

  7. Influence of mold length and mold heat transfer on horizontal continuous casting of nonferrous alloy rods

    NASA Astrophysics Data System (ADS)

    Verwijs, J. P.; Weckman, D. C.

    1988-04-01

    The influence of mold length and mold heat transfer on the conventional hot-top D.C. continuous casting process was studied through numerical simulations and experiments with horizontally cast 20 mm diameter lead and zinc rods. The minimum casting speed was found to be a nonlinear function of the mold length. For short molds, an inverse relationship between mold length and minimum casting speed was observed. However, the minimum casting speed for zinc cast from molds longer than 12 mm was constant at 2.5 mm/s. For lead cast in molds longer than 12 mm, the minimum observed casting speed was constant at 4.0 mm/s. The observed nonlinear relationship between minimum casting speed and mold length was predicted using a numerical model of the process. For this, an analytical expression for the mold boundary conditions was derived which included the influence of gas gap formation between the rod and the mold due to thermoelastic deformations of both the rod and the mold. Correlation between observed and predicted behavior was demonstrated for both the lead and zinc rods. Maximum casting speed was observed to increase with increased mold length; however, this speed was found to be critically dependent on process attributes such as mold and pinch wheel alignment and mold lubrication.

  8. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM, Table 1 Table 1 to Subpart MM of Part 63—General Provisions Applicability to Subpart MM General...

  9. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM, Table 1 Table 1 to Subpart MM of Part 63—General Provisions Applicability to Subpart MM General...

  10. Prototype and estimation an ultrasonic motor using a transmission rod with a stator vibrator and a rotor at the both ends

    NASA Astrophysics Data System (ADS)

    Takano, Takehiro; Tamura, Hideki; Sato, Daisuke; Aoyagi, Manabu

    2012-05-01

    A new structure of ultrasonic motor composed of a stator vibrator, a rotor and an ultrasonic transmission rod is proposed. Two vibrations of a stator vibrator mounted at a rod end excite two orthogonal bending vibrations in the rod and elliptic motions of displacement are formed at another end of the rod. The elliptic motions produce a rotating force to a rotor pressed at the end. The simple structure of mounting and preloading a rotor is designed by FEM. It is checked experimentally that two orthogonal bending vibrations are excited in the rod and the motor operation of the new construction is confirmed.

  11. Failure and penetration response of borosilicate glass during short-rod impact

    SciTech Connect

    Anderson, C. E. Jr.; Orphal, D. L.; Behner, Th.; Hohler, V.; Wickert, M.; Templeton, D. W.

    2007-12-12

    The failure characterization of brittle materials like glass is of fundamental importance in describing the penetration resistance against projectiles. A critical question is whether this failure front remains 'steady' after the driving stress is removed. A test series with short gold rods (D = 1 mm, L/D{approx_equal}5-11) impacting borosilicate glass at {approx}1 to 2 km/s was carried out to investigate this question. The reverse ballistic method was used for the experiments, and the impact and penetration process was observed simultaneously with five flash X-rays and a 16-frame high-speed optical camera. Very high measurement accuracy was established to ensure reliable results. Results show that the failure front induced by rod impact and penetration does arrest (ceases to propagate) after the rod is totally eroded inside the glass. The impact of a second rod after a short time delay reinitiates the failure front at about the same speed.

  12. Correlation between Depth Perception by Three-Rods Test and Stereoacuity by Distance Randot Stereotest

    PubMed Central

    Negayama, Ryo; Sakata, Hiroyuki; Hasebe, Kayoko

    2014-01-01

    Background The examination of depth perception with three-rods test, in addition to visual acuity testing, is required to obtain motor vehicle license to drive taxies and trucks, according to the Road Traffic Act in Japan. The aim of this study was to examine whether the results of the three-rods test would correlate with the results of static stereopsis tests, used in ophthalmic practice. Methods This study involved 54 normal subjects, 9 women and 45 men, with ages ranging from 18 to 25 (mean, 20.8) years. All had visual acuity of 0.8 or better with or without glasses or contact lenses correction and had no strabismus at the distant (5 m) or near (0.3 m) fixation. TNO Stereotest and Titmus Stereotest were examined at 40 cm while Distance Randot Stereotest was at 3 m. At three-rods test, a central rod was moved at the speed of 50 mm/sec forward and backward automatically against two laterally located fixed rods, placed inside the illuminated box. An examinee at the distance of 2.5 m observed the rods inside the box from a small viewing window and pushed a button to stop the central rod in alignment with the fixed rods. Erred distance (mm) of the central rod from the fixed rods as a mean of 4 measurements was correlated with stereoacuity in second of arc, measured by three kinds of the stereopsis tests. Results The erred distance of three-rods test was positively correlated with static stereoacuity at distance measured with Distance Randot Stereotest (ρ = 0.418, p = 0.0023, Spearman rank correlation test) and also with the other stereopsis tests at near fixation. The stereoacuity at near fixation, measured by TNO Stereotest and Titmus Stereotest, was positively correlated with each other (ρ = 0.431, p = 0.0017). Conclusion Three-rods test, examining depth perception, together with the response by eye-hand coordination, gave consistent results with distant static stereoacuity when measured with Distance Randot Stereotest. PMID:25058604

  13. 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.

  14. Application of MM wave therapy in radiology

    SciTech Connect

    Avakian, R.S.; Gasparyan, L.V.

    1995-12-31

    The authors studied the effects of MM wave electromagnetic radiation influence on patients, affected by X-ray radiation during the reparation works after Chernobyl nuclear power plant exposure. They compared results of treatment of two groups of patients: (1) control group patients received only basis therapy; (2) testing group, 10 patients received basis therapy and MM wave influence. The authors used the wide band noise generator `Artsakh - 2` for local irradiation on the acupuncture points. Their data proved that low intensity MM waves have immunocorrective, antioxidant effects, and MM wave therapy is a perspective method for treatment of patients with radiological pathology.

  15. 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.

  16. 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.

  17. Spontaneous Patterning of Confined Granular Rods

    NASA Astrophysics Data System (ADS)

    Galanis, Jennifer; Harries, Daniel; Sackett, Dan L.; Losert, Wolfgang; Nossal, Ralph

    2006-01-01

    Vertically vibrated rod-shaped granular materials confined to quasi-2D containers self-organize into distinct patterns. We find, consistent with theory and simulation, a density dependent isotropic-nematic transition. Along the walls, rods interact sterically to form a wetting layer. For high rod densities, complex patterns emerge as a result of competition between bulk and boundary alignment. A continuum elastic energy accounting for nematic distortion and local wall anchoring reproduces the structures seen experimentally.

  18. 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.

  19. 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.

  20. Improved model for sucker rod pumping

    SciTech Connect

    Doty, D.R.; Schmidt, Z.

    1981-01-01

    An improved model for predicting the behavior of sucker rod pumping installations is presented. This model incorporates the dynamics of the liquid columns as well as the sucker rod string through a system of partial differential equations. The system of equations is solved by a modified method of characteristics on a digital computer. The model predicts the polished rod and pump dynamometer cards and incorporates the effects of liquid inertia and viscosity. It is capable of simulating a wide variety of pumping conditions where liquid physical properties are important. The information predicted by the model is useful in the design and operation of sucker rod pumping installations. Refs.

  1. An improved model for sucker rod pumping

    SciTech Connect

    Doty, D.R.; Schmidt, Z.

    1983-02-01

    An improved model for predicting the behavior of sucker rod pumping installations is presented. This model incorporates the dynamics of the liquid columns as well as the sucker rod string through a system of partial differential equations. This system of equations is solved by a modified method of characteristics on a digital computer. The model predicts the polished-rod and pump dynamometer cards and incorporates the effects of liquid inertia and viscosity. The model is capable of simulating a wide variety of pumping conditions for which liquid physical properties are important. The information predicted by the model is useful in the design and operation of sucker rod pumping installations.

  2. A Toddler's Treatment of "Mm" and "Mm Hm" in Talk with a Parent

    ERIC Educational Resources Information Center

    Filipi, Anna

    2007-01-01

    The study to be reported in this paper examined the work accomplished by "mm" and "mm hm" in the interactions of a parent and his daughter aged 0;10-2;0. Using the findings of Gardner (2001) for adults, the analysis shows that "mm" accomplished a range of functions based on its sequential placement and prosodic features, whereas "mm hm" was much…

  3. The readout driver (ROD) for the ATLAS liquid argon calorimeters

    NASA Astrophysics Data System (ADS)

    Efthymiopoulos, Ilias

    2001-04-01

    The Readout Driver (ROD) for the Liquid Argon calorimeter of the ATLAS detector is described. Each ROD module receives triggered data from 256 calorimeter cells via two fiber-optics 1.28 Gbit/s links with a 100 kHz event rate (25 kbit/event). Its principal function is to determine the precise energy and timing of the signal from discrete samples of the waveform, taken each period of the LHC clock (25 ns). In addition, it checks, histograms, and formats the digital data stream. A demonstrator system, consisting of a motherboard and several daughter-board processing units (PUs) was constructed and is currently used for tests in the lab. The design of this prototype board is presented here. The board offers maximum modularity and allows the development and testing of different PU designs based on today's leading integer and floating point DSPs.

  4. Nonlinear stability analysis of the diffusional spheroidization of rods

    SciTech Connect

    Choy, J.; Hackney, S.A.; Lee, J.K.

    1995-06-01

    Experimental observations have revealed a significant scatter in the spheroidization wavelength in solid rods and rod-shaped inclusions. Using a finite difference method, the role of multiharmonic initial conditions, where the wavelength and amplitude vary with position, is investigated as a cause of the scatter. When the initial amplitude of the radius perturbation is small relative to the radius of the perturbation, the waves with their wavelengths at the maximum growth rate are shown to evolve with little scatter. As the initial amplitude increases, however, a large magnitude of scatter in the growing wavelength is observed due to wave/wave interactions. A simplified, analytical model is also proposed to describe the nonlinear wave/wave interaction between two waves. Based on this model, it is found that the stability of one wave can be affected by the other, and that a new wave can be generated. A wave stability diagram is constructed to predict the stability of a given wave.

  5. Internal hydriding in irradiated defected Zircaloy fuel rods: A review (LWBR Development Program)

    SciTech Connect

    Clayton, J C

    1987-10-01

    Although not a problem in recent commercial power reactors, including the Shippingport Light Water Breeder Reactor, internal hydriding of Zircaloy cladding was a persistent cause of gross cladding failures during the 1960s. It occurred in the fuel rods of water-cooled nuclear power reactors that had a small cladding defect. This report summarizes the experimental findings, causes, mechanisms, and methods of minimizing internal hydriding in defected Zircaloy-clad fuel rods. Irradiation test data on the different types of defected fuel rods, intentionally fabricated defected and in-pile operationally defected rods, are compared. Significant factors affecting internal hydriding in defected Zircaloy-clad fuel rods (defect hole size, internal and external sources of hydrogen, Zircaloy cladding surface properties, nickel alloy contamination of Zircaloy, the effect of heat flux and fluence) are discussed. Pertinent in-pile and out-of-pile test results from Bettis and other laboratories are used as a data base in constructing a qualitative model which explains hydrogen generation and distribution in Zircaloy cladding of defected water-cooled reactor fuel rods. Techniques for minimizing internal hydride failures in Zircaloy-clad fuel rods are evaluated.

  6. Performance evaluation of 4.75-mm NMAS superpave mixture

    NASA Astrophysics Data System (ADS)

    Rahman, Farhana

    A Superpave asphalt mixture with 4.75-mm nominal maximum aggregate size (NMAS) is a promising, low-cost pavement preservation treatment for agencies such as the Kansas Department of Transportation (KDOT). The objective of this research study is to develop an optimized 4.75-mm NMAS Superpave mixture in Kansas. In addition, the study evaluated the residual tack coat application rate for the 4.75-mm NMAS mix overlay. Two, hot-in-place recycling (HIPR) projects in Kansas, on US-160 and K-25, were overlaid with a 15- to 19-mm thick layer of 4.75-mm NMAS Superpave mixture in 2007. The field tack coat application rate was measured during construction. Cores were collected from each test section for Hamburg wheel tracking device (HWTD) and laboratory bond tests performed after construction and after one year in service. Test results showed no significant effect of the tack coat application rate on the rutting performance of rehabilitated pavements. The number of wheel passes to rutting failure observed during the HWTD test was dependent on the aggregate source as well as on in-place density of the cores. Laboratory pull-off tests showed that most cores were fully bonded at the interface of the 4.75-mm NMAS overlay and the HIPR layer, regardless of the tack application rate. The failure mode during pull-off tests at the HMA interface was highly dependent on the aggregate source and mix design of the existing layer material. This study also confirmed that overlay construction with a high tack coat application rate may result in bond failure at the HMA interface. Twelve different 4.75-mm NMAS mix designs were developed using materials from the aforementioned but two binder grades and three different percentages of natural (river) sand. Laboratory performance tests were conducted to assess mixture performance. Results show that rutting and moisture damage potential in the laboratory depend on aggregate type irrespective of binder grade. Anti-stripping agent affects moisture

  7. Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.

    PubMed

    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

    2016-02-01

    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. Connexin 36 and rod bipolar cell independent rod pathways drive retinal ganglion cells and optokinetic reflexes.

    PubMed

    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

    2016-02-01

    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.

  9. Optimization of the structural quality of sapphire rods grown by the Stepanov method in a reducing atmosphere

    SciTech Connect

    Kryvonosov, Ye. V.; Konevskiy, P. V. Lytvynov, L. A.; Tkachenko, V. F.

    2015-03-15

    Historically, the Stepanov method has been used for growing long shaped sapphire crystals (rods, tubes, and ribbons) for practical design. The recent intense development of this technique was stimulated by sapphire applications in optics and electronics; thus, the optical and structural quality of these crystals is of great importance. The results of studying the structural quality of sapphire rods up to 18 mm in diameter grown under optimized conditions are reported.

  10. Introduction to QM/MM simulations.

    PubMed

    Groenhof, Gerrit

    2013-01-01

    Hybrid quantum mechanics/molecular mechanics (QM/MM) simulations have become a popular tool for investigating chemical reactions in condensed phases. In QM/MM methods, the region of the system in which the chemical process takes place is treated at an appropriate level of quantum chemistry theory, while the remainder is described by a molecular mechanics force field. Within this approach, chemical reactivity can be studied in large systems, such as enzymes. In the first part of this contribution, the basic methodology is briefly reviewed. The two most common approaches for partitioning the two subsystems are presented, followed by a discussion on the different ways of treating interactions between the subsystems. Special attention is given on how to deal with situations in which the boundary between the QM and MM subsystems runs through one or more chemical bonds. The second part of this contribution discusses what properties of larger system can be obtained within the QM/MM framework and how. Finally, as an example of a QM/MM application in practice, the third part presents an overview of recent QM/MM molecular dynamics simulations on photobiological systems. In addition to providing quantities that are experimentally accessible, such as structural intermediates, fluorescence lifetimes, quantum yields and spectra, the QM/MM simulations also provide information that is much more difficult to measure experimentally, such as reaction mechanisms and the influence of individual amino acid residues.

  11. The same-source parallel MM{sub 5}.

    SciTech Connect

    Michalakes, J.

    1999-08-23

    The set of architectures available to users of the Penn State/NCAR MM5 has been expanded to included distributed-memory parallel computers, providing cost-effective scalable performance and memory capacity for large problem sizes. The same-source approach uses high-level parallel library and source-translation technology for adapting MM5, simplifying maintenance and allowing new physics modules to be incorporated without modification. The approach facilitates maintenance of the DM-parallel option to MM5 as an option within the official version, rather than as a separate stand-alone version. As a result, the DM-parallel option to MM5 (now at Version 3.1) has been a part of six subsequent model releases since MM5 Version 2.8 in March 1998. The same-source approach is applicable to other, similarly constructed codes when there is a need or desire to develop the code for distributed memory parallel machines without impacting the pre-existing source code. The approach is also compatible with pre-existing loop-level multithreading directives so that the code will run in distributed-memory/shared-memory mode on SMP clusters.

  12. Computing Temperatures In Optically Pumped Laser Rods

    NASA Technical Reports Server (NTRS)

    Farrukh, Usamah O.

    1991-01-01

    Computer program presents new model solving temperature-distribution problem for laser rods of finite length and calculates both radial and axial components of temperature distributions in these rods. Contains several self-checking schemes to prevent over-writing of memory blocks and to provide simple tracing of information in case of trouble. Written in Microsoft FORTRAN 77.

  13. Sucker rod makers offer a selection

    SciTech Connect

    Savage, D.

    1983-11-01

    In their ongoing effort to produce better, more cost-effective sucker rods, manufacturers have selected one of three materials - fiberglass, aluminum, and steel - that they feel best suits the production system function of the rods, which is to connect the downhole pump to the pumpjack on the surface. Characteristics of each are described.

  14. 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)

  15. 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…

  16. MM Algorithms for Geometric and Signomial Programming.

    PubMed

    Lange, Kenneth; Zhou, Hua

    2014-02-01

    This paper derives new algorithms for signomial programming, a generalization of geometric programming. The algorithms are based on a generic principle for optimization called the MM algorithm. In this setting, one can apply the geometric-arithmetic mean inequality and a supporting hyperplane inequality to create a surrogate function with parameters separated. Thus, unconstrained signomial programming reduces to a sequence of one-dimensional minimization problems. Simple examples demonstrate that the MM algorithm derived can converge to a boundary point or to one point of a continuum of minimum points. Conditions under which the minimum point is unique or occurs in the interior of parameter space are proved for geometric programming. Convergence to an interior point occurs at a linear rate. Finally, the MM framework easily accommodates equality and inequality constraints of signomial type. For the most important special case, constrained quadratic programming, the MM algorithm involves very simple updates.

  17. 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.

  18. Attachment for sucker rod depth adjustment

    SciTech Connect

    Collins, N.D.

    1992-04-07

    This patent describes a surface unit of an oil well pumping system, having a walking beam, a suspended carrier bar and an interconnected sucker rod assembly for stroking a reciprocating down-hole pump. It comprises a cross bar having a centrally located passage therein for the sucker rod assembly and adapted to be transversely supported by the carrier bar; a depth adjusting bar, having a centrally located passage therein for the sucker rod assembly, positioned at a selected fixed dimension above and parallel to the cross bar and adapted to operatively support the sucker rod assembly; clamping means for fixing the sucker rod relative to the depth adjusting bar; and hydraulically extendable means supportively connecting the depth adjusting bar to the cross bar on at least each side of the carrier bar for adjusting the selected fixed dimension and maintaining the adjustment during operation.

  19. 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.

  20. Microscopic study of surface degradation of glass fiber-reinforced polymer rods embedded in concrete castings subjected to environmental conditioning

    SciTech Connect

    Bank, L.C.; Puterman, M.

    1997-12-31

    The surface degradation of glass fiber-reinforced polymer (GFRP) pultruded rods when embedded in concrete castings and subjected to environmental conditioning is discussed in this paper. Investigation of the degradation of the GFRP rods were performed using optical microscopy and scanning electron microscopy (SEM). Unidirectionally reinforced pultruded rods (6.3- and 12.7-mm diameters) containing E-glass fibers in polyester and vinylester matrices were conditioned at standard laboratory conditions (21 C, 65% relative humidity) or submerged in aqueous solutions (tap water) at 80 C for durations of 14 and 84 days. Observations of the surfaces and cross-sections of the rods by optical microscopy and SEM revealed a variety of degradation phenomena. Embedded hygrothermally conditioned rods were found to have developed surface blisters of different sizes and depths. SEM studies of the surface revealed degradation of the polymer matrix material and exposure and degradation of the fibers close to the surface of the rods. The rods with the vinylester resin matrix showed less extensive degradation than those with the polyester resin matrix; however, the degradation characteristics of the two types of rods appear to be similar.

  1. QM/MM Calculations on Proteins.

    PubMed

    Ryde, U

    2016-01-01

    In this chapter, I discuss combined quantum mechanics (QM) and molecular mechanics (MM; QM/MM) calculations for proteins. In QM/MM, a small but interesting part of the protein is treated by accurate QM methods, whereas the remainder is treated by faster MM methods. The prime problems with QM/MM calculations are bonds between the QM and MM systems, the selection of the QM system, and the local-minima problem. The two first problems can be solved by the big-QM approach, including in the QM calculation all groups within 4.5-6Å of the active site and all buried charges in the protein. The third problem can be solved by calculating free energies. It is important to study QM/MM energy components to ensure that the results are stable and reliable. They can also be used to understand the reaction and the effect of the surroundings, eg, by dividing the catalytic effect into bonded, van der Waals, electrostatic, and geometric components and to deduce which parts of the protein contribute most to the catalysis. It should be ensured that the QM calculations are reliable and converged by extending the basis set to quadruple-zeta quality, including a proper treatment of dispersion, as well as years experience and method development calculations with both pure and hybrid density functional theory methods. If the latter give differing results, calibration with high-level QM methods is needed. Reactions that change the net charge should be avoided. QM/MM calculations can be combined with experimental methods. PMID:27498637

  2. In Situ Microspectrophotometric Studies on the Pigments of Single Retinal Rods

    PubMed Central

    Liebman, Paul A.

    1962-01-01

    Three spectral entities have been observed in single intact frog rod outer segments at 506 mμ, 480 mμ and 380 mμ. It is likely that the peak of 506 mμ was somewhat altered by bleaching reactions and originated at about 510 mμ. This is identified with the 502 mμ frog rhodopsin of digitonin extracts. Spectra in polarized light have the same maximum, identifying the dichroism of rods with rhodopsin. The dichroic ratio is around 6, giving the outer segment an axial density of 0.09/5μ or 0.9 OD total, with a pigment concentration of 2 to 3 mM. The dichroism data are used to compute the angle separating the rhodopsin molecular absorption vectors in rods from perfect restriction to a plane. This angle is 16° or 23° depending on which of two assumptions one chooses for the type of molecular ordering. The spectral peaks at 480 mμ and 380 mμ are thought to correspond respectively to metarhodopsin and retinene. Disappearance of the former is accompanied by accumulation of the latter. This reaction seems to occur more slowly in the intact outer segment than the corresponding reaction in solution. Spread of bleaching spectra from illuminated to dark areas of the same rod did not occur over distances of 2 μ or greater. Spectra were similar from rod to rod and from point to point on the same rod showing that frog rods are spectrally homogeneous both individually and collectively. PMID:14465191

  3. Spontaneous formation of stringlike clusters and smectic sheets for colloidal rods confined in thin wedgelike gaps.

    PubMed

    Maeda, Hideatsu; Maeda, Yoshiko

    2013-08-20

    Monodispersed colloidal rods of β-FeOOH with sizes ranging from 270 to 580 nm in length and 50 to 80 nm in width were synthesized. Narrow wedgelike gaps (0 to 700 nm in height) were formed around the inner bottom edge of the suspension glass cells. Optical microscopic observations revealed the formation of stringlike clusters of the rods and smectic sheets (by spontaneous side-by-side clustering of the strings) in the isotropic phase of the rod suspensions confined in narrow gaps; the electrolyte (HCl) concentrations of the suspensions are 5-40 mM, at which inter-rod interactions are attractive. The strings exhibit different colors that were used to investigate the structures of the strings with the help of interference color theory for thin films. The results are as follows. (1) The rods, lying flat on the gap bottom, are connected side-by-side and stacked upward to form stringlike clusters with different thicknesses depending on the gap height. (2) The stacking numbers (N(sr)) of the rods are estimated to be 1-5. With N(sr) increasing from 2 to 5, the volume fractions (ϕ) of the rods in the strings increased typically from 0.25-0.3 to 0.35-0.42 to reach limiting values (close to the ϕ values of the rods in the bulk smectic phase). (3) Unexpected low-ϕ strings are found in regions with an intermediate height in the gaps. These behaviors of ϕ may be caused by thermal fluctuations of the strings.

  4. Spontaneous formation of stringlike clusters and smectic sheets for colloidal rods confined in thin wedgelike gaps.

    PubMed

    Maeda, Hideatsu; Maeda, Yoshiko

    2013-08-20

    Monodispersed colloidal rods of β-FeOOH with sizes ranging from 270 to 580 nm in length and 50 to 80 nm in width were synthesized. Narrow wedgelike gaps (0 to 700 nm in height) were formed around the inner bottom edge of the suspension glass cells. Optical microscopic observations revealed the formation of stringlike clusters of the rods and smectic sheets (by spontaneous side-by-side clustering of the strings) in the isotropic phase of the rod suspensions confined in narrow gaps; the electrolyte (HCl) concentrations of the suspensions are 5-40 mM, at which inter-rod interactions are attractive. The strings exhibit different colors that were used to investigate the structures of the strings with the help of interference color theory for thin films. The results are as follows. (1) The rods, lying flat on the gap bottom, are connected side-by-side and stacked upward to form stringlike clusters with different thicknesses depending on the gap height. (2) The stacking numbers (N(sr)) of the rods are estimated to be 1-5. With N(sr) increasing from 2 to 5, the volume fractions (ϕ) of the rods in the strings increased typically from 0.25-0.3 to 0.35-0.42 to reach limiting values (close to the ϕ values of the rods in the bulk smectic phase). (3) Unexpected low-ϕ strings are found in regions with an intermediate height in the gaps. These behaviors of ϕ may be caused by thermal fluctuations of the strings. PMID:23876087

  5. 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

  6. Enhancement of fiberglass sucker-rod design is offered

    SciTech Connect

    Hallden, D.F.

    1985-09-30

    This paper discribes the effective use of fiberglass-reinforced plastic sucker rods (FRP). FRP sucker rods have proven to be an economical solution to many sucker rod beam pumping problems. Two important characteristics that contribute to the effectiveness of FRP sucker rods are effective modulus of elasticity and fatigue life. Computerized simulations show that FRP sucker rod installations can benefit from using rod designs with a lower modulus of elasticity.

  7. Biologically Inspired mm-size Gliding UAV

    NASA Astrophysics Data System (ADS)

    Weihs, Daniel; Zussman, Eyal; Yarin, Alexander

    2002-11-01

    We present a first design of an unmanned aerial vehicle whose aerodynamic loads are carried by comb-like permeable surfaces. This concept was based on observation and analysis of the flight capabilities of the Thrip family of insects, whose have wings of this form and various plant seeds which use this concept to form an aerodynamic decelerator. This concept is only practical for at low Reynolds numbers, as the viscous trace of bodies moving in fluid becomes thicker as Re becomes smaller. When Re<1, a cylinder moving in fluid can drag along fluid up to several cylinder diameters. This drag effect can be used to produce a comb structure, where the ratio of comb rod to inter-rod distance can be up to 0.1 without significant throughflow, i.e. the comb is equivalent to a continuous surface. To demonstrate this principle, we have built artificial ``dandelion seeds", i.e. stable aerodynamic decelerators (parachutes) made of permeable light mats of submicron diameter nanofibers. We produced the nanofiber matrices (mats) by electrospinning of polymer solutions, obtaining fibers of 200-400 nm diameter. These fibers were then deposited on frames that serve to define the aerodynamic surfaces, thus producing the mat, with controllable density. For stability, the aerodynamic surfaces had positive dihedral ( inverted umbrella) forms with the fuselage hanging below. When dropped, the platforms fell freely through the air, apex down, reaching terminal velocity very quickly. By comparing the sink rate of the permeable structures with equivalent decelerators with continuous (Saran-wrap) surfaces we show that the permeable surfaces are equivalent to continuous surfaces, with significant weight savings, as long as the local Reynolds number is o(1).

  8. Dark filaments observed at 8.3mm and 3.1mm wavelength

    NASA Technical Reports Server (NTRS)

    Hiel, E.; Ishiguro, M.; Kosugi, T.; Shibasaki, K.

    1986-01-01

    Mapping of the sun was made at 3.1mm (98 GHz) and 8.3mm (36 GHz) wavelengths with a 45m dish radio telescope at the Nobeyama Cosmic Radio Observatory. The depressions associated with large H alpha filaments are derived to be -0.2 at 8.3mm and -0.05 at 3.1mm, which are darker than the values inferred by Raoult et al. (1979)

  9. Calcium feedback and sensitivity regulation in primate rods

    PubMed Central

    1991-01-01

    Membrane current was recorded from a single primate rod with a suction pipette while the cell was bath perfused with solutions maintained at a temperature of approximately 38 degrees C. A transient inward current was observed at the onset of bright illumination after briefly exposing the outer segment in darkness to Ringer's (Locke) solution containing 3- isobutyl-1-methylxanthine (IBMX), an inhibitor of cGMP phosphodiesterase. After briefly removing external Na+ from around the outer segment in darkness, a similar current was observed upon Na+ restoration in bright light. By analogy to amphibian rods, this inward current was interpreted to represent the activity of an electrogenic Na(+)-dependent Ca2+ efflux, which under physiological conditions in the light is expected to reduce the free Ca2+ in the outer segment and provide negative feedback (the "Ca2+ feedback") to the phototransduction process. The exchange current had a saturated amplitude of up to approximately 5 pA and a decline time course that appeared to have more than one exponential component. In the absence of the Ca2+ feedback, made possible by removing the Ca2+ influx and efflux at the outer segment using a 0 Na(+)-0 Ca2+ external solution, the response of a rod to a dim flash was two to three times larger and had a longer time to peak than in physiological solution. These changes can be approximately accounted for by a simple model describing the Ca2+ feedback in primate rods. The dark hydrolytic rate for cGMP was estimated to be 1.2 s-1. The incremental hydrolytic rate, beta*(t), activated by one photoisomerization was approximately 0.09 s-1 at its peak, with a time-integrated activity, integral of beta*(t)dt, of approximately 0.033, both numbers being derived assuming spatial homogeneity in the outer segment. Finally, we have found that primate rods adapt to light in much the same way as amphibian and other mammalian rods, such as showing a Weber-Fechner relation between flash sensitivity and

  10. A rod-shaped vibro touch sensor using PZT thin film.

    PubMed

    Kanda, T; Morita, T; Kurosawa, M K; Higuchi, T

    1999-01-01

    We have fabricated a probe sensor. This sensor is for high precision coordinate measuring machines, surface roughness measuring tools, or scanning probe microscopes (SPM). This sensor consists of a rod vibrating in the axial direction. The longitudinal vibration was excited and also detected by PZT thin film. The PZT thin film was fabricated by a hydrothermal method. The hydrothermal method uses the reaction process in hot and high pressure aqueous solutions. We made a 27.8-mm long sensor. Its resonance frequency was 116 kHz. The sensitivity and resolution were evaluated by experiments. We succeeded in oscillating the rod and detecting the contact.

  11. Method speeds tapered rod design for directional well

    SciTech Connect

    Hu Yongquan; Yuan Xiangzhong

    1995-10-16

    Determination of the minimum rod diameter, from statistical relationships, can decrease the time needed for designing a sucker-rod string for a directional well. A tapered rod string design for a directional well is more complex than for a vertical well. Based on the theory of a continuous beam column, the rod string design in a directional well is a trial and error method. The key to reduce the time to obtain a solution is to rapidly determine the minimum rod diameter. This can be done with a statistical relationship. The paper describes sucker rods, design method, basic analysis rod design, and minimum rod diameter.

  12. Induced Current Measurement of Rod Vibrations

    NASA Astrophysics Data System (ADS)

    Sawicki, Charles A.

    2003-01-01

    The longitudinal normal modes of vibration of rods are similar to the modes seen in pipes open at both ends. A maximum of particle displacement exists at both ends and an integral number (n) of half wavelengths fit into the rod length. The frequencies fn of the normal modes is given by Eq. (1), where L is the rod length and V is the wave velocity: fn = nV/2L. Many methods have been used to measure the velocity of these waves. The Kundt's tube method commonly used in student labs will not be discussed here. A simpler related method has been described by Nicklin.2 Kluk3 measured velocities in a wide range of materials using a frequency counter and microphone to study sounds produced by impacts. Several earlier methods4,5 used phonograph cartridges complete with needles to detect vibrations in excited rods. A recent interesting experiment6 used wave-induced changes in magnetization produced in an iron rod by striking one end. The travel time, measured as the impulsive wave reflects back and forth, gave the wave velocity for the iron rod. In the method described here, a small magnet is attached to the rod with epoxy, and vibrations are detected using the current induced in a few loops of wire. The experiment is simple and yields very accurate velocity values.

  13. 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.

  14. Gelation and mechanical response of patchy rods.

    PubMed

    Kazem, Navid; Majidi, Carmel; Maloney, Craig E

    2015-10-28

    We perform Brownian dynamics simulations to study the gelation of suspensions of attractive, rod-like particles. We show that in detail the rod-rod surface interactions can dramatically affect the dynamics of gelation and the structure and mechanics of the networks that form. If the attraction between the rods is perfectly smooth along their length, they will collapse into compact bundles. If the attraction is sufficiently corrugated or patchy, over time, a rigid space-spanning network will form. We study the structure and mechanical properties of the networks that form as a function of the fraction of the surface, f, that is allowed to bind. Surprisingly, the structural and mechanical properties are non-monotonic in f. At low f, there are not a sufficient number of cross-linking sites to form networks. At high f, rods bundle and form disconnected clusters. At intermediate f, robust networks form. The elastic modulus and yield stress are both non-monotonic in the surface coverage. The stiffest and strongest networks show an essentially homogeneous deformation under strain with rods re-orienting along the extensional axis. Weaker, more clumpy networks at high f re-orient relatively little with strong non-affine deformation. These results suggest design strategies for tailoring surface interactions between rods to yield rigid networks with optimal mechanical properties.

  15. 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.

  16. Experimental Study on the Influence of the Supporting Condition and Rod Motion on the Fuel Fretting Damage

    SciTech Connect

    Kim, Hyung-Kyu; Lee, Young-Ho

    2007-07-01

    Present study focuses on the influence of a supporting condition and a rod motion on a fuel fretting wear through experiments using a self-developed wear simulator, which was presented at the Water Reactor Fuel Performance Meeting, Kyoto Japan in 2005. In the experiment, a fuel rod specimen of two span lengths is vibrated by two perpendicularly aligned electromagnetic actuators. Both ends of the rod specimen are supported with a positive contact force and a variation of the supporting condition is simulated by moving each of the four grid strap specimens constituting a center grid cell. As for the supporting condition, 0.1 mm gap and 10 N force are used; a circular and a diagonal traces are applied for the rod motion. The contact shape of the spring/dimple is concave, to try and increase the contact area. Both the spring/dimple and fuel rod specimens were fabricated from the as-received materials (zirconium alloy) for a commercial fuel assembly. Experiments are carried out under a room temperature and distilled water condition. Experiment of each condition is carried out for 72 hours. Wear volume, area and depth on the cladding tubes are examined. As a result, the present concave shaped spring/dimple causes less wear when the rod moves in a circular manner than a diagonal one if there is a positive contact force (10 N). However, a diagonal motion causes more wear when a gap (0.1 mm) exists. Wear amount at the spring and dimple is influenced by the location of them and the rod motion. It is found that the wear is concentrated at the contact edges between the spring/dimple and rods due to the contact shape. The influence of the rod motion on the worn area and its shape is also discussed. (authors)

  17. Conductance changes produced by light in rod outer segments

    PubMed Central

    Falk, Gertrude; Fatt, P.

    1968-01-01

    1. Changes in the admittance of rod outer segments produced by illumination with brief flashes were studied by two methods: one, in which maintained changes in real and imaginary parts of admittance were observed in the frequency range 15 c/s-60 kc/s; the other, in which the time course of change in absolute value of admittance (Δ|Y|) was observed at frequencies of 100 kc/s-1·0 Mc/s. 2. The response to light absorbed by rhodopsin was resolved into components. One of these components was a transient increase in conductance which arose from a rapid degradation into heat of the light energy. Another component, prominent at high frequencies where the conductivity of the rod interior was accessible to measurement, was produced by the uptake of H+ by visual pigment in its conversion from metarhodopsin I to metarhodopsin II, causing a change in ionization of buffer. 3. Two other components, designated I and II, appeared as maintained changes of admittance involving the organized structure of the rod. Component I appeared as a frequency-independent increase in the real part of admittance (ΔG), the amplitude of which varied in proportion to the conductivity of the medium, without specificity as to ion species. Component II appeared as a ΔG which rose linearly with log frequency over the range 1-60 kc/s, while the imaginary part of admittance change (ΔB) rose to a plateau which was maintained for more than a tenfold frequency range. This component was unaffected by variations in conductivity in the region of low conductivities. 4. When rods were suspended in a solution containing 100 mM hydroxylamine, component II no longer appeared as a maintained admittance change while component I was unaffected. Examination of the time course of response showed component II to appear transiently, decaying over the course of 2 sec following a flash. 5. Measurements of Δ|Y| for rods in solutions of widely different conductivities showed component II to have a more rapid time course

  18. Laparoscopic cholecystectomy using 2-mm instruments.

    PubMed

    Uranüs, S; Peng, Z; Kronberger, L; Pfeifer, J; Salehi, B

    1998-10-01

    Today, laparoscopic cholecystectomy is the method of choice for treatment of symptomatic gallbladder disorders. It minimizes effects of the operation that are independent of the gallbladder, such as trauma to the abdominal wall and other soft tissue. The surgical wounds were even smaller when 2-mm trocars were used. Laparoscopic cholecystectomy using 2-mm instruments was performed in a consecutive series of 14 patients with symptomatic gallstones. The procedure was completed in 12 cases, with conversion to open surgery in two cases. Intraoperative cholangiography was always performed. The postoperative course was always uneventful. The cosmetic effect was highly satisfactory. The procedure using 2-mm instruments could be indicated in selected patients with uncomplicated gallstone disease. PMID:9820716

  19. Laparoscopic cholecystectomy using 2-mm instruments.

    PubMed

    Uranüs, S; Peng, Z; Kronberger, L; Pfeifer, J; Salehi, B

    1998-10-01

    Today, laparoscopic cholecystectomy is the method of choice for treatment of symptomatic gallbladder disorders. It minimizes effects of the operation that are independent of the gallbladder, such as trauma to the abdominal wall and other soft tissue. The surgical wounds were even smaller when 2-mm trocars were used. Laparoscopic cholecystectomy using 2-mm instruments was performed in a consecutive series of 14 patients with symptomatic gallstones. The procedure was completed in 12 cases, with conversion to open surgery in two cases. Intraoperative cholangiography was always performed. The postoperative course was always uneventful. The cosmetic effect was highly satisfactory. The procedure using 2-mm instruments could be indicated in selected patients with uncomplicated gallstone disease.

  20. Microeconomics of 300-mm process module control

    NASA Astrophysics Data System (ADS)

    Monahan, Kevin M.; Chatterjee, Arun K.; Falessi, Georges; Levy, Ady; Stoller, Meryl D.

    2001-08-01

    Simple microeconomic models that directly link metrology, yield, and profitability are rare or non-existent. In this work, we validate and apply such a model. Using a small number of input parameters, we explain current yield management practices in 200 mm factories. The model is then used to extrapolate requirements for 300 mm factories, including the impact of simultaneous technology transitions to 130nm lithography and integrated metrology. To support our conclusions, we use examples relevant to factory-wide photo module control.

  1. 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.

  2. 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.

  3. Method of cleaning and inhibiting sucker rod corrosion

    SciTech Connect

    Ford, M. B.; Griffin, J. B.

    1985-01-22

    Method of cleaning tubular goods, especially sucker rods, and inhibiting the sucker rods against corrosion as the rod string is being withdrawn from a borehole. The method is carried out by the provision of an enclosure which is attached to the upper end of a cased borehole. The upper end of the sucker rod string is extended axially through the enclosure as the rod string is withdrawn from the casing. A medial length of the rod string is engaged by a resilient packer device which wipes the rod clean of well fluids and loose debris. The rod string is next cleaned within a second chamber by impacting the outer surface thereof with an abrasive substance. The rod surface is again cleaned of any residual material. The rod is then moved through another chamber where corrosion inhibitor is applied to the external surface of the rod. As each treated joint of rod is withdrawn from the enclosure, the rod joints are sequentially unscrewed and suitably stacked, where the rods are protected from the elements, as well as being protected when the rods are subsequently made up into a rod string as the rod is replaced into a borehole.

  4. Film Programmer's Guide to 16mm Rentals.

    ERIC Educational Resources Information Center

    Artel, Linda J., Ed.; Weaver, Kathleen, Ed.

    The guide is geared to reflect the expanding interest in the history of cinema, in underground and experimental films, in social and political documentaries as well as more conventional Hollywood and foreign classics. It lists over 8,000 16mm films selected from 50 United States distributors. A title directory contains information concerning the…

  5. CCM3 to MM5 Data Conversion

    2007-03-02

    The accompanying script (which uses the NCAR Command Language) ready output from the Community Climate Model Code, version 3 (CCM3) and converts it to input format for the Mesoscale Model, version 5 (MM5) code. The script utilizes a Fortran binary write routine.

  6. Mm-wave power meter mount

    NASA Technical Reports Server (NTRS)

    Mullen, D. L.; Oltmans, D. A.; Stelzried, C. T.

    1968-01-01

    E-band thermistor mount and a technique for adjusting a temperature compensating thermistor to provide an electrically balanced bridge are used for measuring RF power in the mm-wavelength. The mount is relatively insensitive to temperature effects that cause measurement errors in single ended circuits.

  7. The attenuation of rod signals by bleachings

    PubMed Central

    Alpern, M.; Rushton, W. A. H.; Torii, S.

    1970-01-01

    1. Contrast flash technique allows the rod threshold to be measured even when it lies far above the cone threshold. In this way the rod dark adaptation curve after rhodopsin bleaching can be measured over 6 log units. 2. By retinal densitometry the regeneration of rhodopsin can be measured in the same subject. It is found that the log threshold is raised 1·2 units for each 10% of rhodopsin in the bleached state. 3. We have tried to discover whether bleaching raises the threshold by desensitizing the rods, or (like backgrounds) by attenuating their signals. Neither suggestion satisfies all conditions. 4. All are satisfied by [Formula: see text], where N is the size of rod signal, constant for threshold; θ, θD are steady backgrounds of light and receptor noise; ϕ is the threshold flash with σ a constant of about 2·5 log td sec; B the fraction of pigment in the bleached state. PMID:5499030

  8. Control rod for a nuclear reactor

    DOEpatents

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

    1979-01-01

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

  9. Pulsed positive discharges in air at moderate pressures near a dielectric rod

    NASA Astrophysics Data System (ADS)

    Dubinova, A.; Trienekens, D.; Ebert, U.; Nijdam, S.; Christen, T.

    2016-10-01

    We study pulsed positive discharges in air in a cylindrically symmetric setup with an electrode needle close (about 1 mm) above the top of a dielectric cylindrical rod of 4 mm in diameter mounted at its bottom on a grounded plate electrode. We present ICCD (intensified charge-coupled device) pictures and evaluations of experiments as well as simulations with a fluid discharge model; the simulations use cylindrical symmetry. In the experiments, there is an initial inception cloud phase, where the cylindrical symmetry is maintained, and later a streamer phase, where it is broken spontaneously. At 75-150 mbar, discharges with cylindrical symmetry are not attracted to the dielectric rod, but move away from it. The dielectric rod plays the sole role of an obstacle that shades (in the context of photoionization) a cone-shaped part of the inception cloud; the cone size is determined by the geometry of the setup. The material properties of the dielectric rod, such as its dielectric permittivity and the efficiency of the photon induced secondary electron emission do not have a noticeable effect. This is due to the abundance of photoionization in air, which supplies a positive discharge with free electrons and allows it to propagate along the electric field lines. Using some simple field calculations, we show that field enhancement due to dielectric polarization does not play a significant role in our geometry as long as the discharge maintains its cylindrical symmetry. The field component towards the rod is insufficiently enhanced to cause the discharge to move towards the rod. Any additional electrons produced by the dielectric surface do not influence this discharge morphology. This interpretation is supported by both experiments and simulations. At higher pressures (400-600 mbar) or for larger gaps between the needle and the dielectric rod, the inception cloud reaches its maximal radius within the gap between needle and rod and destabilizes there. In those cases

  10. 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.

  11. 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.

  12. 1984 tubing and sucker rod tables

    SciTech Connect

    Not Available

    1984-01-01

    The first section of this handy reference lists companies that produce API tubing and couplings, giving specifications for pipe in sizes from 3/4 to 41/2 in. Also listed and illustrated are special tubing joints, identified by manufacturer Additional tables provide details on API sucker rods, including manufacturers, mechanical and chemical properties, dimensions and make-up recommendations. Similar data are presented for non-API rods.

  13. Close packing of rods on spherical surfaces.

    PubMed

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-28

    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.

  14. 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.

  15. Oil well sucker rod shock absorber

    SciTech Connect

    Knox, F.B.

    1986-02-18

    An oil well sucker rod shock absorber is described which consists of: an outer cylindrical casing defined by a cylindrical wall and having a removable upper plug and lower plug disposed respectively at upper and lower extremities of the casing. The upper plug has an axial bore and the lower plug defines a closed lower end and has an upwardly facing top surface. The plunger rod is connected to the sucker rod and is slidably disposed in the bore of the upper plug. A piston within the cylindrical casing is coupled to the plunger rod and has a downwardly facing bottom surface. Biasing means have a maximum vertical length disposed vertically within the casing and extending between the downwardly facing surface of the piston and the upwardly facing surface of the lower plug means at all times. This allows vertical reciprocal translation of the plunger rod and the piston within the cylindrical casing downwardly against the biasing means. Apertures are disposed through the cylindrical casing along the entire length thereof opposite the length of the biasing means, allowing downhole fluid pressure to be applied to the piston within the cylindrical casing via the apertures to be added to the force of the biasing means, without causing a fluid lock within the cylinder. Slap and wear of the sucker rod resulting therefrom are reduced and damage prevented.

  16. Crippling Strength of Axially Loaded Rods

    NASA Technical Reports Server (NTRS)

    Natalis, FR

    1921-01-01

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

  17. Long-Rod Moving-Plate Interaction

    NASA Astrophysics Data System (ADS)

    Partom, Y.

    2002-07-01

    Understanding the mechanics of interaction of a long rod projectile with a forward moving plate at an angle is essential to understanding long rod interaction with an explosive reactive armor cassette. To investigate the mechanics of such an interaction we use AUTODIN2D/EULER in plane geometry, although the problem is 3D. We assume that this is a satisfactory approximation, as we're only interested in the main features, and are not comparing fine details to experimental results. From the simulations we learn that the interaction never reaches steady state. Initially each material splits into two streams, and the interaction plane is perpendicular to the rod. But with time the interaction plane rotates slowly, until it becomes parallel to the rod, which is then able to continue moving forward without interruption. During this process interacting rod material of length DeltaL is diverted at an angle and becomes ineffective for penetrating the main target. We made many such runs to determine the dependence of DeltaL on the parameters of the problem. This dependence makes it possible to predict DeltaL for a variety of rod-plate situations.

  18. Close packing of rods on spherical surfaces.

    PubMed

    Smallenburg, Frank; Löwen, Hartmut

    2016-04-28

    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. PMID:27131565

  19. Mechanical performance of fiberglass sucker-rod strings

    SciTech Connect

    Tripp, H.A.

    1988-08-01

    The natural frequencies of fiberglass sucker-rod strings can be calculated by treating the rod strings as modified spring/mass vibration systems. The ratio of the pumping-unit operating speed to the rod-string natural frequency can then be used as a basis for understanding fiberglass-rod performance and for predicting downhole pump stroke lengths.

  20. 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.

  1. 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.

  2. Terahertz/mm wave imaging simulation software

    NASA Astrophysics Data System (ADS)

    Fetterman, M. R.; Dougherty, J.; Kiser, W. L., Jr.

    2006-10-01

    We have developed a mm wave/terahertz imaging simulation package from COTS graphic software and custom MATLAB code. In this scheme, a commercial ray-tracing package was used to simulate the emission and reflections of radiation from scenes incorporating highly realistic imagery. Accurate material properties were assigned to objects in the scenes, with values obtained from the literature, and from our own terahertz spectroscopy measurements. The images were then post-processed with custom Matlab code to include the blur introduced by the imaging system and noise levels arising from system electronics and detector noise. The Matlab code was also used to simulate the effect of fog, an important aspect for mm wave imaging systems. Several types of image scenes were evaluated, including bar targets, contrast detail targets, a person in a portal screening situation, and a sailboat on the open ocean. The images produced by this simulation are currently being used as guidance for a 94 GHz passive mm wave imaging system, but have broad applicability for frequencies extending into the terahertz region.

  3. Mechanics of high speed impact at normal incidence between plasticine long rods and plates

    NASA Astrophysics Data System (ADS)

    Johnson, W.; Sengupta, A. K.; Ghosh, S. K.; Reid, S. R.

    1981-12-01

    A BRIEF literature review of long rod impact is given. Experimental results and observations on the penetration and perforation of plasticine targets of finite thickness (25 and 50 mm) impinged upon normally by long rods of plasticine of various length-to-diameter ratios (2-12) are presented and discussed. An account of the range of modes of deformation as it pertains to long rods and targets of identical materials is given, i.e. mushrooming of the projectile leading-end, partial penetration and embedment of the projectile in the target, gross target penetration by the projectile, and penetration followed by perforation. The difference in penetration behaviour as between long and short rods is discussed. Plasticine has been used for both the target and projectile materials in order to simulate hypervelocity impact conditions for deformable long rod projectiles on deformable target plates. This permits the use of equipment based on an industrial stud driver which is substantially cheaper than the equipment (e.g. a light gas gun) required to achieve the range of speeds necessary for hypervelocity conditions with real ballistics-related metals and alloys. Projectile-target interactions and damage observed in the present tests compare well with those reported in similar investigations using metallic projectiles and targets. The attraction of performing ballistics experiments with plasticine models outweighs such inherent limitations as the inability to model the extreme conditions of temperature and strain-hardening in real materials, because testing is cheap and easily performed in a laboratory.

  4. Formation of a pinched electron beam and an intense x-ray source in radial foil rod-pinch diodes

    NASA Astrophysics Data System (ADS)

    Sorokin, S. A.

    2016-04-01

    Low-impedance rod-pinch diode experiments were performed on the MIG generator at Institute of High Current Electronics using an aluminum foil placed between concentric electrodes of a rod-pinch diode. The J × B force accelerates the foil plasma in the axial and radial directions. After the foil plasma is pushed beyond the tip of the rod, a vacuum gap and a pinched electron beam form. The anode and cathode plasmas expansion and the following plasmas sweeping up by the J × B force can result in repetitive gap formations and closures, which are evident in the several successive intense x-ray pulses. A 0.7-mm-size point-like x-ray source was realized using a 1-mm-diameter tungsten rod, tapered to a point over the last 10 mm. The results of experiments show that the foil-shorted rod-pinch diode configuration has the potential to form low-impedance diodes, to shorten x-ray pulse duration and to realize submillimeter spot-size x-ray sources.

  5. Two-Phase Flow Patterns in a Four by Four Rod Bundle

    SciTech Connect

    Yoshitaka Mizutani; Shigeo Hosokawa; Akio Tomiyama

    2006-07-01

    Air-water two-phase flow patterns in a four by four square lattice rod bundle consisting of an acrylic channel box of 68 mm in width and transparent rods of 12 mm in diameter were observed by utilizing a high speed video camera, FEP (fluorinated ethylene propylene) tubes for rods, and a fiber-scope inserted in a rod. The FEP possesses the same refractive index as water, and thereby, whole flow patterns in the bundle and local flow patterns in subchannels were successfully visualized with little optical distortion. The ranges of liquid and gas volume fluxes, and , in the present experiments were 0.1 < < 2.0 m/s and 0.04 < < 8.85 m/s, which covered typical two-phase flow patterns appearing in a fuel bundle of a boiling water nuclear reactor. As a result, the following conclusions were obtained: (1) the region of slug flow in the - flow pattern diagram is so narrow that it can be regarded as a boundary between bubbly and churn flows, (2) the boundary between bubbly and churn flows is close to the boundary between bubbly and slug flows of the Mishima and Ishii's flow pattern transition model, and (3) the boundary between churn and annular flows is well predicted by the Mishima and Ishii's model. (authors)

  6. Photovoltage of Rods and Cones in the Macaque Retina

    NASA Astrophysics Data System (ADS)

    Schneeweis, David M.; Schnapf, Julie L.

    1995-05-01

    The kinetics, gain, and reliability of light responses of rod and cone photoreceptors are important determinants of overall visual sensitivity. In voltage recordings from photoreceptors in an intact primate retina, rods were found to be functionally isolated from each other, unlike the tightly coupled rods of cold-blooded vertebrates. Cones were observed to receive excitatory input from rods, which indicates that the cone pathway also processes rod signals. This input might be expected to degrade the spatial resolution of mesopic vision.

  7. 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.

  8. 1 mm ultrafast superconducting stripline molecule detector

    NASA Astrophysics Data System (ADS)

    Zen, N.; Casaburi, A.; Shiki, S.; Suzuki, K.; Ejrnaes, M.; Cristiano, R.; Ohkubo, M.

    2009-10-01

    Superconducting stripline detectors (SSLDs) are promising for detecting keV molecules at nanosecond response times and with mass-independent detection efficiency. However, a fast response time is incompatible with practical centimeter detector size. A parallel configuration of striplines provides a means to address this problem. Experimental results and simulation for promisingly large 1-mm-square parallel niobium SSLDs show that nanosecond pulses are produced by superconducting-normal transition within only one of the parallel striplines instead of cascade switching of all the parallel striplines. Successful detection of a series of multimers of immunoglobulin G up to 584 kDa supports the mass-independent efficiency for mass spectrometry.

  9. End fitting for oil well sucker rods

    SciTech Connect

    Fischer, C.P.

    1984-02-07

    An end fitting for a sucker rod for oil wells is described with the end fitting having a chamber portion extending inwardly from one end thereof and an externally threaded portion at its other end. The chamber portion is defined by a plurality of spaced-apart annular ridges which define frusto-conical shaped cavities therebetween. The end fitting also has a bore extending inwardly thereinto from its other end which communicates with the inner end of the chamber portion. A valve is mounted in the end fitting and has a valve stem positioned in the bore and a valve head positioned at the inner end of the chamber portion. The chamber portion is adapted to receive a glass reinforced resin bonded cylindrical rod which is maintained therein by a two-part epoxy resin which surrounds the rod and is received in the cavities to form epoxy wedges bonded to the rod. The outer end of the bore is provided with internal threads which threadably receive a screw therein which engages the end of the valve stem so that longitudinal force may be applied to the valve thereby transmitting longitudinal force to the end of the rod.

  10. Dynamic behavior of rod photoreceptor disks.

    PubMed Central

    Chen, Chunhe; Jiang, Yunhai; Koutalos, Yiannis

    2002-01-01

    Eukaryotic cells use membrane organelles, like the endoplasmic reticulum or the Golgi, to carry out different functions. Vertebrate rod photoreceptors use hundreds of membrane sacs (the disks) for the detection of light. We have used fluorescent tracers and single cell imaging to study the properties of rod photoreceptor disks. Labeling of intact rod photoreceptors with membrane markers and polar tracers revealed communication between intradiskal and extracellular space. Internalized tracers moved along the length of the rod outer segment, indicating communication between the disks as well. This communication involved the exchange of both membrane and aqueous phase and had a time constant in the order of minutes. The communication pathway uses approximately 2% of the available membrane disk area and does not allow the passage of molecules larger than 10 kDa. It was possible to load the intradiskal space with fluorescent Ca(2+) and pH dyes, which reported an intradiskal Ca(2+) concentration in the order of 1 microM and an acidic pH 6.5, both of them significantly different than intracellular and extracellular Ca(2+) concentrations and pH. The results suggest that the rod photoreceptor disks are not discrete, passive sacs but rather comprise an active cellular organelle. The communication between disks may be important for membrane remodeling as well as for providing access to the intradiskal space of the whole outer segment. PMID:12202366

  11. 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.

  12. Coordinated mm/sub-mm observations of Sagittarius A* in May 2007

    NASA Astrophysics Data System (ADS)

    Kunneriath, D.; Eckart, A.; Vogel, S.; Sjouwerman, L.; Wiesemeyer, H.; Schödel, R.; Baganoff, F. K.; Morris, M.; Bertram, T.; Dovciak, M.; Dowries, D.; Duschl, W. J.; Karas, V.; Konig, S.; Krichbaum, T.; Krips, M.; Lu, R.-S.; Markoff, S.; Mauerhan, J.; Meyer, L.; Moultaka, J.; Muzic, K.; Najarro, F.; Schuster, K.; Straubmeier, C.; Thum, C.; Witzel, G.; Zamaninasab, M.; Zensus, A.

    2008-10-01

    At the center of the Milky Way, with a distance of thicksim8 kpc, the compact source Sagittarius A* (SgrA*) can be associated with a super massive black hole of thicksim4x 106Modot. SgrA* shows strong variability from the radio to the X-ray wavelength domains. Here we report on simultaneous NIR/sub-millimeter/X-ray observations from May 2007 that involved the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope, the Australian Telescope Compact Array (ATCA), the US mm-array CARMA, the IRAM 30m mm-telescope, and other telescopes. We concentrate on the time series of mm/sub-mm data from CARMA, ATCA, and the MAMBO bolometer at the IRAM 30m telescope.

  13. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  14. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  15. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  16. Interpretation of calculated forces on sucker rods

    SciTech Connect

    Lea, J.F.; Pattillo, P.D. ); Studenmund, W.R. )

    1995-02-01

    The analysis of working loads in a sucker rod string during a pumping cycle has received substantial coverage in the petroleum literature. These load predictions have tended to focus on mechanical design considerations such as excess load and fatigue prediction. In contrast, the current study addresses the issues of buckling associated with working axial/pressure loads in an attempt to clarify the means of both predicting buckling and minimizing its effects. The study begins with a review of the static loads acting near the pump, and proceeds to a discussion of how these loads relate to the tendency of a rod string to buckle on the downstroke. Critical to this discussion is the concept of effective tension. Definition of the effective tension leads to the application of this concept to sinker bar design as a means of mitigating the buckling tendency of a rod string. Key points are reinforced by illustrative examples.

  17. System analysis for sucker-rod pumping

    SciTech Connect

    Schmidt, Z.; Doty, D.R.

    1989-05-01

    Pumping free gas in an oil well can significantly decrease the efficiency of a sucker-rod-pumping installation. Pump placement depth and use of a downhole gas/liquid separator (gas anchor) were found to be significant variables in improving the overall efficiency. A procedure is presented that shows when and to what degree the use of a gas anchor improves the efficiency of a sucker-rod pumping system. It was found that at lower pump intake pressures, the gas anchor usually improves efficiency, but at higher pump intake pressures, use of a gas anchor produces no positive effect. Also, elevating the pump to the highest position that still allows proper pump loading was found to reduce the operating costs of a sucker-rod-pumping installation significantly. Finally, a procedure is presented to calculate directly the pump volumetric efficiency and required volumetric pump displacement rate.

  18. System analysis for sucker rod pumping

    SciTech Connect

    Schmidt, Z.; Doty, D.R.

    1986-01-01

    Pumping free gas in an oil well can significantly decrease the efficiency of a sucker rod pumping installation. Pump placement depth and the use of a down hole gas-liquid separator (gas anchor) found to be significant variables in improving the overall efficiency. A procedure is presented which shows when and by how much the use of a gas anchor improves the efficiency of a sucker rod pumping system. It was found that at lower pump intake pressures the gas anchor usually improves efficiency, while at higher pump intake pressures the use of a gas anchor will produce no positive effect. Also, it was found at elevating the pump to the highest position which still allows for proper pump loading can significantly reduce the operating costs for a sucker rod pumping installation. Finally, a procedure is presented for directly calculating pump volumetric efficiency as well as the required volumetric pump displacement rate.

  19. 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.

  20. 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.

  1. Ultra-high vacuum compatible induction-heated rod casting furnace.

    PubMed

    Bauer, A; Neubauer, A; Münzer, W; Regnat, A; Benka, G; Meven, M; Pedersen, B; Pfleiderer, C

    2016-06-01

    We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bars. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely, the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.

  2. Ultra-high vacuum compatible induction-heated rod casting furnace.

    PubMed

    Bauer, A; Neubauer, A; Münzer, W; Regnat, A; Benka, G; Meven, M; Pedersen, B; Pfleiderer, C

    2016-06-01

    We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bars. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely, the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb. PMID:27370472

  3. Ultra-high vacuum compatible induction-heated rod casting furnace

    NASA Astrophysics Data System (ADS)

    Bauer, A.; Neubauer, A.; Münzer, W.; Regnat, A.; Benka, G.; Meven, M.; Pedersen, B.; Pfleiderer, C.

    2016-06-01

    We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bars. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely, the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.

  4. Prediction of Stereochemistry using Q2MM

    PubMed Central

    2016-01-01

    Conspectus The standard method of screening ligands for selectivity in asymmetric, transition metal-catalyzed reactions requires experimental testing of hundreds of ligands from ligand libraries. This “trial and error” process is costly in terms of time as well as resources and, in general, is scientifically and intellectually unsatisfying as it reveals little about the underlying mechanism behind the selectivity. The accurate computational prediction of stereoselectivity in enantioselective catalysis requires adequate conformational sampling of the selectivity-determining transition state but has to be fast enough to compete with experimental screening techniques to be useful for the synthetic chemist. Although electronic structure calculations are accurate and general, they are too slow to allow for sampling or fast screening of ligand libraries. The combined requirements can be fulfilled by using appropriately fitted transition state force fields (TSFFs) that represent the transition state as a minimum and allow fast conformational sampling using Monte Carlo. Quantum-guided molecular mechanics (Q2MM) is an automated force field parametrization method that generates accurate, reaction-specific TSFFs by fitting the functional form of an arbitrary force field using only electronic structure calculations by minimization of an objective function. A key feature that distinguishes the Q2MM method from many other automated parametrization procedures is the use of the Hessian matrix in addition to geometric parameters and relative energies. This alleviates the known problems of overfitting of TSFFs. After validation of the TSFF by comparison to electronic structure results for a test set and available experimental data, the stereoselectivity of a reaction can be calculated by summation over the Boltzman-averaged relative energies of the conformations leading to the different stereoisomers. The Q2MM method has been applied successfully to perform virtual ligand

  5. Prediction of Stereochemistry using Q2MM.

    PubMed

    Hansen, Eric; Rosales, Anthony R; Tutkowski, Brandon; Norrby, Per-Ola; Wiest, Olaf

    2016-05-17

    The standard method of screening ligands for selectivity in asymmetric, transition metal-catalyzed reactions requires experimental testing of hundreds of ligands from ligand libraries. This "trial and error" process is costly in terms of time as well as resources and, in general, is scientifically and intellectually unsatisfying as it reveals little about the underlying mechanism behind the selectivity. The accurate computational prediction of stereoselectivity in enantioselective catalysis requires adequate conformational sampling of the selectivity-determining transition state but has to be fast enough to compete with experimental screening techniques to be useful for the synthetic chemist. Although electronic structure calculations are accurate and general, they are too slow to allow for sampling or fast screening of ligand libraries. The combined requirements can be fulfilled by using appropriately fitted transition state force fields (TSFFs) that represent the transition state as a minimum and allow fast conformational sampling using Monte Carlo. Quantum-guided molecular mechanics (Q2MM) is an automated force field parametrization method that generates accurate, reaction-specific TSFFs by fitting the functional form of an arbitrary force field using only electronic structure calculations by minimization of an objective function. A key feature that distinguishes the Q2MM method from many other automated parametrization procedures is the use of the Hessian matrix in addition to geometric parameters and relative energies. This alleviates the known problems of overfitting of TSFFs. After validation of the TSFF by comparison to electronic structure results for a test set and available experimental data, the stereoselectivity of a reaction can be calculated by summation over the Boltzman-averaged relative energies of the conformations leading to the different stereoisomers. The Q2MM method has been applied successfully to perform virtual ligand screens on a range of

  6. 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.

  7. Pattern selection dynamics in rod eutectics

    NASA Astrophysics Data System (ADS)

    Serefoglu, Melis

    The cooperative or diffusively coupled growth of multiple phases during solidification is one of the most widely observed and generally important classes of phase transformations in materials. Technologically, low melting temperature and small freezing range contribute to excellent casting fluidity and fine composite structures give rise to favorable properties. Both of these features contribute to the wide application of eutectic alloys in the casting, welding, and soldering of engineered components. Despite the broad-based technological importance, many fundamental questions regarding eutectic solidification remain unanswered, severely limiting our ability to employ computational methods in the prediction of microstructure for the effective design of new materials and processes. At the core of the most persistent questions, lie problems involving multicomponent thermodynamics, solid-liquid and solid-solid interfacial phenomena, morphological stability, chemical and thermal diffusion, and nucleation phenomena. In the current study, pattern selection dynamics in rod eutectics are investigated using systematic directional solidification experiments and phase field simulations. Directional solidification of a succinonitrile-camphor (SCN-DC) transparent alloy in thin slab geometries of various thicknesses reveals two main points. First, a velocity is indentified at which a transition in array basis vectors is observed in specimens with many rows of rods (i.e. bulk). This transition amounts to a 90 degree rotation of the rod array, shifting from alignment of 1st nearest neighbors to alignment of 2nd nearest neighbors along the slide wall. Second, significant array distortion is observed with decreasing slide thickness, delta, which ultimately leads to a single-row (quasi-3D) morphology where delta/lambda is on the order of unity. In our analysis of these observations, we use a geometrical model to describe the rod arrangement as a function of slide thickness, providing

  8. 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.

  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. 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.

  11. Energy distributions in rods and beams

    NASA Technical Reports Server (NTRS)

    Wohlever, J. C.; Bernhard, R. J.

    1989-01-01

    A hypothesis proposed by Nefske and Sung (1987) that the mechanical energy flow in acoustic/structural systems can be modeled using a thermal energy flow analogy was tested for both longitudinal vibration in rods and transverse flexural vibrations in beams. It was found that the rod behaves according to the energy flow analogy. However, the beam solutions behaved significantly differently than predicted by the thermal analogy, unless spatially averaged energy and power flow were considered. Otherwise, the beam analysis is restricted to frequencies where the near-field terms in the displacement solution are negligible over most of the beam.

  12. HIGH STRENGTH CONTROL RODS FOR NEUTRONIC REACTORS

    DOEpatents

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

    1961-07-11

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

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

    PubMed

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

    2006-12-01

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

  14. 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.

  15. Waveguide for transmitting and radiating high-frequency, high-power ultrasound using higher mode vibrations of a cylindrical rod.

    PubMed

    Hatano, Hajime

    2005-04-01

    It was shown that a cylindrical solid rod, with a diameter several times larger than the wavelength, can be used as an efficient waveguide for transmitting and radiating high-power ultrasound at higher frequencies. A number of cylindrical rods of varying size and material were tested, and their efficiency as a waveguide was evaluated by the measurements of mechanoacoustic efficiency when the radiating end of the rod was immersed in water for an acoustical load. As an example of waveguide application, a mock-up water atomizer was constructed and shown to work stably at a continuous input of 200 W at 500 kHz. As a consequence of analytical and experimental considerations of the higher mode vibrations of cylindrical rods, a diagram for the optimal design of the waveguides was constructed. For instance, an aluminum alloy rod 6.9 cm in diameter and 23.3 cm in length yielded a mechanoacoustic efficiency as high as 88% at 500 kHz. For high temperature applications, the cylindrical rod can be used as a radiator of heat, as well as for a separator of the piezoelectric transducer from the hot object.

  16. A laser scanner for 35mm film

    NASA Technical Reports Server (NTRS)

    Callen, W. R.; Weaver, J. E.

    1977-01-01

    The design, construction, and testing of a laser scanning system is described. The scanner was designed to deliver a scanned beam over a 2.54 cm by 2.54 cm or a 5.08 cm by 5.08 cm format. In order to achieve a scan resolution and rate comparable to that of standard television, an acousto-optic deflector was used for one axis of the scan, and a light deflecting galvanometer for deflection along the other axis. The acoustic optic deflector has the capability of random access scan controlled by a digital computer.

  17. Period of vibration of axially vibrating truly nonlinear rod

    NASA Astrophysics Data System (ADS)

    Cveticanin, L.

    2016-07-01

    In this paper the axial vibration of a muscle whose fibers are parallel to the direction of muscle compression is investigated. The model is a clamped-free rod with a strongly nonlinear elastic property. Axial vibration is described by a nonlinear partial differential equation. A solution of the equation is constructed for special initial conditions by using the method of separation of variables. The partial differential equation is separated into two uncoupled strongly nonlinear second order differential equations. Both equations, with displacement function and with time function are exactly determined. Exact solutions are given in the form of inverse incomplete and inverse complete Beta function. Using boundary and initial conditions, the frequency of vibration is obtained. It has to be mentioned that the determined frequency represents the exact analytic description for the axially vibrating truly nonlinear clamped-free rod. The procedure suggested in this paper is applied for calculation of the frequency of the longissimus dorsi muscle of a cow. The influence of elasticity order and elasticity coefficient on the frequency property is tested.

  18. Numerical modelling of longitudinal vibrations of a sucker rod string

    NASA Astrophysics Data System (ADS)

    Shardakov, I. N.; Wasserman, I. N.

    2010-03-01

    A new technique for analyzing the dynamic behavior of a sucker rod string used in the oil well industry is presented. The main difficulty in the numerical calculation of the examined structure is a multivalued velocity—force relation determined by Coulomb's friction and by loads generated during operation of pump valves. Both the monotonic and nonmonotonic velocity—force relations are considered. A quasi-variational inequality formulation of the problem is proposed. The solution of the inequality amounts to finding the minimum of a convex nonsmooth functional at each time step by means of the Newmark difference time scheme, successive iterations and finite element discretization. The problem of functional minimization is reduced to construction of a sequence of smooth nonlinear programming problems by introducing the auxiliary variables and applying the augmented Lagrangian method. The proposed approach is used to study the longitudinal vibrations of sucker rod strings under near-real conditions. In such systems the most commonly occurring vibration modes are the stick-slip vibrations and the vibrations with natural force excited twice a cycle. The nonmonotonic character of the friction law leads to intensification of these vibrations. In the case of nonmonotonic friction law the stick-slip vibrations can occur even under the action of constant external forces.

  19. From the nm to the Mm

    NASA Astrophysics Data System (ADS)

    Villa, I. M.

    2003-12-01

    Tectonic models for the evolution of an orogen start at the Mm scale, and use field work on smaller subunits at the km scale and rocks collected at the m scale. At the mm scale, minerals are identified, analyzed by mass spectrometry, their "cooling ages" assigned to a specific closure temperature, a cooling rate attributed to a particular tectonic regime, and a large body of self-referential literature is the product of an oiled machinery. Problems become apparent if one attempts to harmonize mm-scale science with the nasty little details at even smaller scales. Atoms are invisible to the naked eye (unlike the minerals mentioned above) and their actual behavior is, or was, only accessible to indirect argumentations and simplified calculations. Increased computing power now allows calculating the transport of atoms in a crystal from the Schr”dinger equation: results do not fit 19th century continuum physics for infinitely dilute solutions (Fick's and Arrhenius' "laws"). Moreover, improved nanochemical analyses allow characterizing the supposedly homogeneous mineral matrix. TEM images show how layers or chains in pristine minerals are substituted in a non-periodic way by alteration products. EMP analyses show the almost ubiquitous presence of razor-sharp boundaries rather than Erf profiles. Disequilibrium recrystallization textures thus prevail over diffusive reequilibration; diffusion sensu stricto is shown to be a much slower process than heterochemical replacement. Alterability sequences are well known to surface scientists: e.g. halite, olivine, biotite, muscovite, zircon. Such sequences are reflected in the isotopic retentivity. The link only becomes clear at the nm scale: isotopic exchange occurs during the replacement reactions that affect all rocks on their retrograde P-T evolution. This is sufficient to explain why zircons record higher isotopic ages than muscovites, which in turn undergo less isotope exchange than biotites etc. While there is a vague

  20. Research on pinching characteristics of electron beams emitted from different cathode surfaces of a rod-pinch diode

    SciTech Connect

    Gao Yi; Qiu Aici; Zhang Zhong; Zhang Pengfei; Wang Zhiguo; Yang Hailiang

    2010-07-15

    The particle-in-cell code UNIPIC is used to simulate the working process of a rod-pinch diode and investigate the pinching characteristics of electron beams emitted from different cathode surfaces. The simulation results indicate that the electron beam emitted from the upstream surface pinches better than from other surfaces when all the three surfaces emit electrons. The charge-density deposition on the anode surface peaks at the rod tip while the deposited charge density is approximately uniform over the first 15 mm of the rod before rapidly increasing over the last 3 mm, indicating a large axial extent of electron deposition. For the case of single-surface emission, the pinching quality of the electron beam emitted from the downstream surface is better than those from other surfaces. The charge-density deposition peaks at the rod tip and decreases rapidly off the tip. Based on the relationship of Larmor radius, beam's self-magnetic field, and the spatial current distribution, the above simulation results are analyzed theoretically. The experiments are performed on the inductive voltage adder to examine the simulations. By comparing the axial distribution of the radiation on the anode rod measured with the pinhole camera and the on-axis forward x-ray dose measured with the LiF thermoluminescent detectors, the simulation results are verified. The electron emission suppression method and the impedance change for each case are investigated or discussed in this paper.

  1. Research on pinching characteristics of electron beams emitted from different cathode surfaces of a rod-pinch diode

    NASA Astrophysics Data System (ADS)

    Gao, Yi; Qiu, Aici; Zhang, Zhong; Zhang, Pengfei; Wang, Zhiguo; Yang, Hailiang

    2010-07-01

    The particle-in-cell code UNIPIC is used to simulate the working process of a rod-pinch diode and investigate the pinching characteristics of electron beams emitted from different cathode surfaces. The simulation results indicate that the electron beam emitted from the upstream surface pinches better than from other surfaces when all the three surfaces emit electrons. The charge-density deposition on the anode surface peaks at the rod tip while the deposited charge density is approximately uniform over the first 15 mm of the rod before rapidly increasing over the last 3 mm, indicating a large axial extent of electron deposition. For the case of single-surface emission, the pinching quality of the electron beam emitted from the downstream surface is better than those from other surfaces. The charge-density deposition peaks at the rod tip and decreases rapidly off the tip. Based on the relationship of Larmor radius, beam's self-magnetic field, and the spatial current distribution, the above simulation results are analyzed theoretically. The experiments are performed on the inductive voltage adder to examine the simulations. By comparing the axial distribution of the radiation on the anode rod measured with the pinhole camera and the on-axis forward x-ray dose measured with the LiF thermoluminescent detectors, the simulation results are verified. The electron emission suppression method and the impedance change for each case are investigated or discussed in this paper.

  2. 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.

  3. 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.

  4. SecA drives transmembrane insertion of RodZ, an unusual single-span membrane protein.

    PubMed

    Rawat, Swati; Zhu, Lu; Lindner, Eric; Dalbey, Ross E; White, Stephen H

    2015-03-13

    The transmembrane (TM) helices of most type II single-span membrane proteins (S-SMPs) of Escherichia coli occur near the N-terminus, where the cell's targeting mechanisms can readily identify it as it emerges from the ribosome. However, the TM helices of a few S-SMPs, such as RodZ, occur a hundred or more residues downstream from the N-terminus, which raises fundamental questions about targeting and assembly. Because of RodZ's novelty and potential usefulness for understanding TM helix insertion in vivo, we examined its membrane targeting and assembly. We used RodZ constructs containing immunotags before the TM domain to assess membrane insertion using proteinase K digestion. We confirmed the N(in)-C(out) (type II) topology of RodZ and established the absence of a targeting signal other than the TM domain. RodZ was not inserted into the membrane under SecA depletion conditions or in the presence of sodium azide, which is known to inhibit SecA. Insertion failed when the TM proton gradient was abolished with Carbonyl cyanide m-chlorophenyl hydrazone. Insertion also failed when RodZ was expressed in SecE-depleted E. coli, indicating that the SecYEG translocon is required for RodZ assembly. Protease accessibility assays of RodZ in other E. coli depletion strains revealed that insertion is independent of SecB, YidC, and SecD/F. Insertion was found to be only weakly dependent on the signal recognition particle pathway: insertion was weakly dependent on the Ffh but independent of FtsY. We conclude that membrane insertion of RodZ requires only the SecYEG translocon, the SecA ATPase motor, and the TM proton motive force.

  5. Analysis of sucker rod and sinkerbar failures

    SciTech Connect

    Waggoner, J.R.; Buchheit, R.G.

    1993-03-01

    This report presents results of a study of performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, finite element analysis, and failure data collection. Metallography showed that the microstructure of the steel bar stock needs to be considered to improve the fatigue resistance of the sucker rod strings. The current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding, and tensile strength is not always a good measure of fatigue resistance. Finite element analysis of the threaded connection quantitatively assesses the coupling designs under various loading conditions. Subcritical fractures in metallography are also suggested by calculated stress distribution in threaded coupling. Failure data illustrates both magnitude and frequency of failures, as well as categorizing the suspected cause of failure. Application of the results in each of these project areas is expected to yield improved choice of metal bar stock, thread design, and make-up practices which can significantly reduce the frequency of sucker rod failures. Sucker rod failures today are not inherent in the process, but can be minimized through the application of new technology and observation of common-sense practices.

  6. Program optimizes sucker-rod pumping mode

    SciTech Connect

    Takacs, G. )

    1990-10-01

    Direct energy costs for sucker-rod pumping can be optimized by selecting the right pump size, stroke length, and pumping speed for the required liquid production rate. Calculation procedures for a computer program are developed for optimizing the design of conventional pumping units.

  7. Stop sucker rod failures to save money

    SciTech Connect

    Moore, K.H.

    1981-07-01

    This study presents examples of frequent and common sucker rod failures, explains how failures occur, presents methods to recognize these failures, and discusses changes in conditions that cause failure. From early identification, corrective measures can be taken to prevent their recurrence, reducing downtime and lost production.

  8. Method of making class D sucker rods

    SciTech Connect

    Woodings, R. T.

    1984-12-04

    It has been found that API Class D sucker rods can be made inexpensively from low-alloy, low-cost steel by following a suitable induction-normalizing process and using a suitable steel to which there has been added 0.07 to 0.15 percent of vanadium.

  9. Wear simulation of sucker rod couplings

    SciTech Connect

    Schumacher, W.J. )

    1991-09-01

    This paper reports that sucker rod strings are devices used to actuate pumps located at the bottom of oil wells. The individual rods are connected together by threaded couplings. Since the couplings have a larger diameter than the rods, they sometimes contact the inside diameter of the tubing during the up and down pumping cycle. Usually, this is not problem unless buckling occurs in the downstroke; however, this can lead to accelerated wear of the coupling and tubing. In nonvertical wells (offset, deviated, or slanted), the contact is more severe and rapid wear takes place. Couplings are more easily replaced during shutdowns; it is very important to minimize wear to tubing since it is virtually impossible to replace. TRIBONIC 20, an iron-based alloy containing approximately 13% Mn, 5% Si, 5.5% Cr, and 5% Ni, was laboratory evaluated to determine whether or not it could solve the sucker rod coupling-production tubing wear problem. The alloy demonstrated outstanding wear resistance both to itself and in protecting type 1019 steel.

  10. Piston rod seal for a Stirling engine

    DOEpatents

    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.

  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. 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.

  13. A Cambrian origin for vertebrate rods

    PubMed Central

    Asteriti, Sabrina; Grillner, Sten; Cangiano, Lorenzo

    2015-01-01

    Vertebrates acquired dim-light vision when an ancestral cone evolved into the rod photoreceptor at an unknown stage preceding the last common ancestor of extant jawed vertebrates (∼420 million years ago Ma). The jawless lampreys provide a unique opportunity to constrain the timing of this advance, as their line diverged ∼505 Ma and later displayed high-morphological stability. We recorded with patch electrodes the inner segment photovoltages and with suction electrodes the outer segment photocurrents of Lampetra fluviatilis retinal photoreceptors. Several key functional features of jawed vertebrate rods are present in their phylogenetically homologous photoreceptors in lamprey: crucially, the efficient amplification of the effect of single photons, measured by multiple parameters, and the flow of rod signals into cones. These results make convergent evolution in the jawless and jawed vertebrate lines unlikely and indicate an early origin of rods, implying strong selective pressure toward dim-light vision in Cambrian ecosystems. DOI: http://dx.doi.org/10.7554/eLife.07166.001 PMID:26095697

  14. Dark Current and Photocurrent in Retinal Rods

    PubMed Central

    Hagins, W. A.; Penn, R. D.; Yoshikami, S.

    1970-01-01

    The interstitial voltages, currents, and resistances of the receptor layer of the isolated rat retina have been investigated with arrays of micropipette electrodes inserted under direct visual observation by infrared microscopy. In darkness a steady current flows inward through the plasma membrane of the rod outer segments. It is balanced by equal outward current distributed along the remainder of each rod. Flashes of light produce a photocurrent which transiently reduces the dark current with a waveform resembling the PII and a-wave components of the electroretinogram. The photocurrent is produced by a local action of light within 12 μm of its point of absorption in the outer segments. The quantum current gain of the photocurrent is greater than 106. The electrical space constant of rat rods is greater than 25 μm, so that the electrical effects of the photocurrent are large enough at the rod synapses to permit single absorbed photons to be detected by the visual system. The photocurrent is apparently the primary sensory consequence of light absorption by rhodopsin. ImagesFigure 3Figure 8Figure 14 PMID:5439318

  15. Rod Soltis: Making Connections. Appalachian Scene.

    ERIC Educational Resources Information Center

    Baldwin, Fred D.

    1998-01-01

    Describes the work of Rod Soltis in developing interlinked telecommunications networks in all 14 of New York's Appalachian counties. The networks connect to each other, state and federal agencies and networks, schools, social service agencies, hospitals, and museums, and include private partnerships with telephone and cable TV companies. Soltis'…

  16. Interactions and collective behavior of attractive colloidal rods and microspheres grafted with filamentous bacteriophage

    NASA Astrophysics Data System (ADS)

    Huang, Fei

    Interactions and collective behavior are investigated for two systems of attractive colloidal rods and colloidal stars. Attractive colloidal rods are constructed by grafting the temperature-sensitive polymer poly(N-isopropylacrylamide) (PNIPAM) to the surface of the semi-flexible filamentous fd virus. The phase diagram of fd-PNIPAM system becomes independent of ionic strength at high salt concentration and low temperature, i.e., the rods are sterically stabilized by the polymer. However, the network of rods undergoes a sol-gel transition as the temperature is raised. The viscoelastic moduli of fd and fd-PNIPAM suspensions are compared as a function of temperature, and the effect of ionic strength on the gelling behavior of fd-PNIPAM solution is measured. For all fluidlike and solidlike samples, the frequency-dependant linear viscoelastic moduli can be scaled onto universal master curves. Colloidal stars are constructed by grafting to 1 mum polystyrene beads a dense brush of 1 mum long and 10 nm wide semi-flexible filamentous viruses. The pair interaction potentials of colloidal stars are measured using an experimental implementation of umbrella sampling, a technique originally developed in computer simulations in order to probe rare events. The influence of ionic strength and grafting density on the interaction is measured. Good agreements are found between the measured interactions and theoretical predictions based upon the osmotic pressure of counterions.

  17. Design and finite element analysis of a novel sliding rod microscrew implantation device for mandibular prognathism

    PubMed Central

    Li, Yanfeng; Lv, Yuan; Lu, Yongjin; Zeng, Pan; Zeng, Xianglong; Guo, Xiaoqian; Han, Weili

    2015-01-01

    Tooth distalization is an effective approach for mandibular prognathism. Current distalization devices are bulky and clinically complicated. Here, we designed a novel molar distalization device by using a sliding rod and a microscrew and performed a mechanical analysis and finite element model (FEM) analysis of force distribution and displacement of the upper canine, first and second premolar and first molar. A 2D FEM was constructed using the Beam3 element and a 3D FEM was constructed of the mandibular teeth, the periodontal membrane, and the alveolar bones using the UG software. The upper first molar was divided into 12 points on the dental surface to facilitate stress analysis. Force analysis using the ANSYS WORKBECNH revealed that, both horizontally and vertically, the traction force causing distalization of the first molar decreased when the spring coil moved down the L shaped sliding rod. The 3D FEM force analysis revealed distomedial displacement of the upper first molar when the sliding rod microscrew implantation device caused distalization of the molar. These findings support further exploration for the use of the sliding rod microscrew implants as an anchorage for group distal movement of the teeth of patients with mandibular prognathism. PMID:26379860

  18. The MM/PBSA and MM/GBSA methods to estimate ligand-binding affinities

    PubMed Central

    Genheden, Samuel; Ryde, Ulf

    2015-01-01

    Introduction: The molecular mechanics energies combined with the Poisson–Boltzmann or generalized Born and surface area continuum solvation (MM/PBSA and MM/GBSA) methods are popular approaches to estimate the free energy of the binding of small ligands to biological macromolecules. They are typically based on molecular dynamics simulations of the receptor–ligand complex and are therefore intermediate in both accuracy and computational effort between empirical scoring and strict alchemical perturbation methods. They have been applied to a large number of systems with varying success. Areas covered: The authors review the use of MM/PBSA and MM/GBSA methods to calculate ligand-binding affinities, with an emphasis on calibration, testing and validation, as well as attempts to improve the methods, rather than on specific applications. Expert opinion: MM/PBSA and MM/GBSA are attractive approaches owing to their modular nature and that they do not require calculations on a training set. They have been used successfully to reproduce and rationalize experimental findings and to improve the results of virtual screening and docking. However, they contain several crude and questionable approximations, for example, the lack of conformational entropy and information about the number and free energy of water molecules in the binding site. Moreover, there are many variants of the method and their performance varies strongly with the tested system. Likewise, most attempts to ameliorate the methods with more accurate approaches, for example, quantum-mechanical calculations, polarizable force fields or improved solvation have deteriorated the results. PMID:25835573

  19. Experimental investigation of a mm-wave planar antenna

    NASA Astrophysics Data System (ADS)

    Lambrakakis, Georgios D.

    1990-06-01

    This thesis investigates a new mm-wave Bilateral Slot Line (BSL) antenna and its relation to the Linearly Tapered Slot Antenna (LTSA). The BSL antenna consists of a tapered double-sided slotline and can be viewed as two identical LTSAs sandwiched back to back. Dielectric substrates with permittivities of 2.33 and 6.0 were used to construct these antennas. The theoretical background, the design, and the performance in the frequency range 5 to 9 GHz of the new microwave integrated circuit antenna is presented. The effects of several parameters such as dielectric constant, stripline and slotline characteristic impedance, antenna structure, and transition scheme on the radiation patterns and return loss were experimentally investigated. Some relationships between the width of stripline and slotline, their characteristic impedance and the dielectric constant are reported. Guidelines are laid to design the LTSA and BSL antennas.

  20. A comparison of 9-inch, 70mm, and 35mm cameras

    NASA Technical Reports Server (NTRS)

    Clegg, R. H.; Scherz, J. P.

    1975-01-01

    Successful aerial photography depends on aerial cameras that provide acceptable photographs within the cost restrictions of the job. For topographic mapping where ultimate accuracy is required, only large-format mapping cameras will suffice. For mapping environmental patterns of vegetation, soils, or water pollution, 9-inch cameras often exceed accuracy and cost requirements, and small formats may be an overall better choice. In choosing the best camera for environmental mapping, relative capabilities and costs must be understood. This study compares resolution, photo interpretation potential, metric accuracy, and cost of 9-inch, 70 mm, and 35 mm cameras for obtaining simultaneous color and color-infrared photography for environmental mapping purposes.

  1. Improved designs reduce sucker-rod pumping costs

    SciTech Connect

    Takacs, G.

    1996-10-07

    Pumping mode selection, optimum counterbalance determination, and rod string design are factors that can reduce operational costs and improve sucker-rod pumping operations. To maximize profits from sucker-rod pumped wells, designs must aim at technically and economically optimum conditions. Assessment of surface and downhole energy losses are basic considerations for improving system efficiency. It is important to properly select the pumping mode, such as the combination of plunger size, pumping speed, stroke length, and rod taper design. The best pumping mode maximizes lifting efficiency and, at the same time, reduces prime-mover power requirements and electrical costs. Surface equipment operational efficiency can be improved with optimum counterbalancing of the pumping unit, and top achieve an ideal sucker-rod pumping system, a tapered rod string must have a proper mechanical design. The paper discusses rod pumping, downhole energy losses, surface losses, optimum efficiency, mode selection, counterbalancing, minimizing the cyclic load factor, and rod string design.

  2. 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.

  3. 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

  4. 32 CFR 989.21 - Record of decision (ROD).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the signator. A ROD (40 CFR 1505.2) is a concise public document stating what an agency's decision is... ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.21 Record of decision (ROD). (a) The proponent and the...

  5. Control rod reactivity measurement by rod-drop method at a fast critical assembly

    SciTech Connect

    Song, L.; Yin, Y.; Lian, X.; Zheng, C.

    2012-07-01

    Rod-drop experiments were carried out to estimate the reactivity of the control rod of a fast critical assembly operated by CAEP. Two power monitor systems were used to obtain the power level and integration method was used to process the data. Three experiments were performed. The experimental results of the reactivity from the two power monitor systems were consistent and showed a reasonable range of reactivity compared to results from positive period method. (authors)

  6. Composite models for combined rod and fluid dynamics in sucker-rod pumping well systems

    SciTech Connect

    Lekia, S.D.L.

    1989-01-01

    This study presents the derivation and the numerical solution of composite models in which both the rod string and the fluid dynamics are coupled so as to accurately account for the effects of viscous friction in sucker-rod pumped wells. A viscous damped hyperbolic first order partial differential equation is coupled to the time derivative of Hooke's law to model the rod string motion and Navier Stokes equations are used to model the fluid dynamics in the rod-tubing annulus. A set of four equations comprise the composite model from which four sub-models for different flow scenarios are considered. The equations are solved numerically by a shock capturing algorithm known as the MacCormack Explicit Scheme which is a two-step predictor-corrector scheme and is second order accuracy in time and space. Five example problems covering various pump setting depths, fluid properties and surface pumping unit kinematics are presented to study the effects of certain important variables. From the analyses of the results of these example problems it is concluded that (1) while the effects of fluid dynamics may appear masked in shallow to medium depth sucker-rod pumped wells, they can not be ignored in deeper wells where large discrepancies occur in the prediction of system parameters, (2) the load range decreases moderately as viscosity increases and the predicted polished rod horsepower does not change significantly over the range of viscosities studied in shallow to medium depth sucker-rod pumped wells, (3) the presence of small quantities of the gas phase in the fluid column reduces system peak torque and precipitate the need for smaller counterbalance weights and (4) the influence of two-phase gas-liquid flow in the rod-tubing annulus on system design parameters declines with increasing pump setting depth. The results are compared against other design models appearing in the literature.

  7. Coiled-coil unwinding at the smooth muscle myosin head-rod junction is required for optimal mechanical performance.

    PubMed Central

    Lauzon, A M; Fagnant, P M; Warshaw, D M; Trybus, K M

    2001-01-01

    Myosin II has two heads that are joined together by an alpha-helical coiled-coil rod, which can separate in the region adjacent to the head-rod junction (Trybus, K. M. 1994. J. Biol. Chem. 269:20819-20822). To test whether this flexibility at the head-rod junction is important for the mechanical performance of myosin, we used the optical trap to measure the unitary displacements of heavy meromyosin constructs in which a stable coiled-coil sequence derived from the leucine zipper was introduced into the myosin rod. The zipper was positioned either immediately after the heads (0-hep zip) or following 15 heptads of native sequence (15-hep zip). The unitary displacement (d) decreased from d = 9.7 +/- 0.6 nm for wild-type heavy meromyosin (WT HMM) to d = 0.1 +/- 0.3 nm for the 0-hep zip construct (mean +/- SE). Native values were restored in the 15-hep zip construct (d = 7.5 +/- 0.7 nm). We conclude that flexibility at the myosin head-rod junction, which is provided by an unstable coiled-coil region, is essential for optimal mechanical performance. PMID:11259302

  8. 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

  9. Colour mixing LEDs with short microsphere doped acrylic rods.

    PubMed

    Deller, Chris; Smith, Geoff; Franklin, Jim

    2004-07-26

    The output colour distributions from red, green and blue (RGB) LEDs mixed with cross linked PMMA micro particle doped PMMA mixing rods is compared to output from a plain PMMA mixing rod. Distinctive patterns with clear colour separation result with the undoped rod. These are homogenised by our mixers, resulting in white light. Light output has been photographed, measured and computer simulated at a distance of 10 cm from the output end of the rods.

  10. GRIN lens rod based probe for endoscopic spectral domain optical coherence tomography with fast dynamic focus tracking

    NASA Astrophysics Data System (ADS)

    Xie, Tuqiang; Guo, Shuguang; Chen, Zhongping; Mukai, David; Brenner, Matthew

    2006-04-01

    In this manuscript, a GRIN (gradient index) lens rod based probe for endoscopic spectral domain optical coherence tomography (OCT) with dynamic focus tracking is presented. Current endoscopic OCT systems have a fixed focal plane or working distance. In contrast, the focus of this endoscopic OCT probe can dynamically be adjusted at a high speed (500 mm/s) without changing reference arm length to obtain high quality OCT images for contact or non-contact tissue applications, or for areas of difficult access for probes. The dynamic focusing range of the probe can be from 0 to 7.5 mm without moving the probe itself. The imaging depth is 2.8 mm and the lateral scanning range is up to 2.7 mm or 4.5 mm (determined by the diameter of different GRIN lens rods). Three dimensional imaging can be performed using this system over an area of tissue corresponding to the GRIN lens surface. The experimental results demonstrate that this GRIN lens rod based OCT system can perform a high quality non-contact in vivo imaging. This rigid OCT probe is solid and can be adapted to safely access internal organs, to perform front or side view imaging with an imaging speed of 8 frames per second, with all moving parts proximal to the GRIN lens, and has great potential for use in extremely compact OCT endoscopes for in vivo imaging in both biological research and clinical applications.

  11. Carbon Inverse Opal Rods for Nonenzymatic Cholesterol Detection.

    PubMed

    Zhong, Qifeng; Xie, Zhuoying; Ding, Haibo; Zhu, Cun; Yang, Zixue; Gu, Zhongze

    2015-11-18

    Carbon inverse opal rods made from silica photonic crystal rods are used for nonenzymatic cholesterol sensing. The characteristic reflection peak originating from the physical periodic structure works as sensing signals for quantitatively estimating cholesterol concentrations. Carbon inverse opal rods work both in cholesterol standard solutions and human serum. They are suitable for practical use in clinical diagnose. PMID:26415111

  12. Measurement of the Speed of Sound in a Metal Rod.

    ERIC Educational Resources Information Center

    Mak, Se-yuen; Ng, Yee-kong; Wu, Kam-wah

    2000-01-01

    Suggests two improved methods to measure the speed of sound in a metal rod. One employs a fast timer to measure the time required for a compression pulse to travel along the rod from end to end, and a second uses a microphone to measure the frequency of the fundamental mode of a freely suspending singing rod. (Author/ASK)

  13. 32 CFR 989.21 - Record of decision (ROD).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... prepare a draft ROD, formally staff it through the MAJCOM EPC, to HQ USAF/A7CI for verification of... the signator. A ROD (40 CFR 1505.2) is a concise public document stating what an agency's decision is... conclusion, the reason for the selection, and the alternatives considered. The ROD must identify the...

  14. Carbon Inverse Opal Rods for Nonenzymatic Cholesterol Detection.

    PubMed

    Zhong, Qifeng; Xie, Zhuoying; Ding, Haibo; Zhu, Cun; Yang, Zixue; Gu, Zhongze

    2015-11-18

    Carbon inverse opal rods made from silica photonic crystal rods are used for nonenzymatic cholesterol sensing. The characteristic reflection peak originating from the physical periodic structure works as sensing signals for quantitatively estimating cholesterol concentrations. Carbon inverse opal rods work both in cholesterol standard solutions and human serum. They are suitable for practical use in clinical diagnose.

  15. ROD MILL ROOM, LOOKING EAST, SHOWING DENVER SPIRAL CLASSIFIER, WITH ...

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

    ROD MILL ROOM, LOOKING EAST, SHOWING DENVER SPIRAL CLASSIFIER, WITH DOMINION ROD MILL IN LEFT BACKGROUND. WATER WAS ADDED TO ORE IN ROD MILL TO MAKE A SLURRY CALLED SLIME. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  16. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intramedullary fixation rod. 888.3020 Section 888.3020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3020 Intramedullary fixation rod. (a) Identification. An intramedullary fixation rod...

  17. 21 CFR 888.3020 - Intramedullary fixation rod.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Intramedullary fixation rod. 888.3020 Section 888.3020 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3020 Intramedullary fixation rod. (a) Identification. An intramedullary fixation rod...

  18. 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)

  19. 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.

  20. Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands

    NASA Technical Reports Server (NTRS)

    Karpov, A.; Carter, M.; Lazareff, B.; Billon-Pierron, D.; Gundlach, K. H.

    1992-01-01

    We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K.

  1. Cleanroom compatible anodization cell for 150 mm Si wafers

    NASA Astrophysics Data System (ADS)

    Bardwell, Jennifer A.; LeBrun, Les; Evans, R. James; Curry, Donald G.; Abbott, Roger

    1996-06-01

    A cleanroom compatible anodization cell for use with 150 mm Si wafers has been constructed and tested. The material of construction is polyvinylidene fluoride, Kynar■, with Chemraz■ (elastomeric polytetrafluoroethylene) O-rings used for sealing. The back contact is made through a dilute HF solution, thus eliminating the possibility for metallic contamination which exists for other forms of back contact. Pt electrodes immersed in the back contact and front contact solutions are the primary electrical connection sites. Ellipsometry, Fourier transform infrared spectroscopy (FTIR), and dilute HF etch rate experiments were used to characterize the as-grown and annealed anodic oxides produced in this cell. Ellipsometric thickness mapping showed excellent lateral oxide uniformity over the entire anodized area; the standard deviations were <2 Å (for oxides ≤100 Å in thickness), <6 Å (for oxides ≤400 Å in thickness), and <10 Å (for oxides <500 Å in thickness). The properties of the oxides, as evaluated by FTIR spectroscopy are essentially identical to those grown on small-area samples using conventional anodization with a metallic back contact.

  2. Slow Slip Events on a 760 mm Long Granite Sample

    NASA Astrophysics Data System (ADS)

    Mclaskey, G.; Yamashita, F.

    2015-12-01

    We describe slow slip events and dynamic rupture events generated on a newly constructed large-scale biaxial friction apparatus at Cornell University that provide insights into the mechanisms of aseismic and seismic slip. We find that, under nominally similar experimental conditions, the 760 mm long granite sample sometimes slips in dynamic stick-slip events and sometimes relieves accumulated shear stress through slow slip events. To provide insights into this curious behavior and the underlying mechanisms, fault slip and shear stress are each measured at 8 locations along the 760 mm long fault. This allows us to map slow slip fronts and the nucleation and propagation of dynamic fault rupture. The granite sample is also instrumented with an array of piezoelectric sensors that are the laboratory equivalent of a seismic network. When the sample is loaded relatively slowly, at 0.03 MPa/s, slow slip occurs on large sections of the fault and the slow slipping region soon expands to the sample boundary. In this case, stress is released in a slow slip event with peak slip velocities < 2 mm/s. Alternatively, when one end of the sample is loaded rapidly (4 MPa/s), or the sample is allowed to heal in stationary contact for a few minutes, slow slip initiates near the load point and accelerates to slip velocities exceeding 200 mm/s before the slow slipping region expands all the way to the sample boundary. This produces a dynamic slip event (stick-slip). The dynamic slip events radiate seismic waves equivalent to a M = -2.5 earthquake. In contrast, the laboratory-generated slow slip events are predominantly aseismic and produce only bursts of tiny and discrete seismic events (M = -6) reminiscent of swarms of microseismicity. The experiments illustrate how a single fault can slide slowly and aseismically or rapidly and dynamically depending on stress state and loading conditions. We compare the behavior observed on this Cornell apparatus to the behavior of other large

  3. Light and dark active phosphodiesterase regulation in salamander rods

    PubMed Central

    1991-01-01

    We studied the activation of 3',5'-cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE) by using a cell-permeant enzyme inhibitor. Rods of Ambystoma tigrinum held in a suction electrode were jumped into a stream of 3-isobutyl-1-methylxanthine (IBMX), 0.01-1 mM. Initial transient light-sensitive currents fit the notion that dark and light-activated forms of PDE contributed independently to metabolic activity and were equivalently inhibited by IBMX (apparent Ki 30 microns). Inhibition developed within 50 ms, producing a step decrease of enzyme velocity, which could be offset by activation with flashes or steps of light. The dark PDE activity was equivalent to light activation of enzyme by 1,000 isomerization rod-1s-1, sufficient to hydrolyze the free cGMP pool (1/e) in 0.6 s. Steady light activated PDE in linear proportion to isomerization rate, the range from darkness to current saturation amounting to a 10-fold increase. The conditions for simultaneous onset of inhibitor and illumination to produce no net change of membrane current defined the apparent lifetime of light- activated PDE, TPDE* = 0.9 s, which was independent of both background illumination and current over the range 0-3 x 10(5) isomerization s-1, from 50 to 0 pA. Adaptation was a function of current rather than isomerization: jumps with different proportions of IBMX concentration to steady light intensity produced equal currents, and followed the same course of adaptation in maintained light, despite a 10-fold difference of illumination. Judged from the delay between IBMX- and light-induced currents, the dominant feedback regulatory site comes after PDE on the signal path. The dark active PDE affects the hydrolytic flux and cytoplasmic diffusion of cGMP, as well as the proportional range of the cGMP activity signal in response to light. PMID:1722240

  4. SU-E-I-29: Generalized Relative Object Detectability (G-ROD): A Metric for Comparing X-Ray Imaging Detector Systems

    SciTech Connect

    Singh, V; Jain, A; Bednarek, D; Rudin, S

    2014-06-01

    Purpose: To determine the relative task-specific performance of two x-ray imaging detectors including the effect of other components of the imaging chain. Methods: The relative object detectability (ROD) was defined as the ratio of the integral of the detective-quantum efficiency (DQE) of a detector weighted by the square of the Fourier Transform (or frequency spectrum) of the object to the same integral for a second detector. The generalized ROD (G-ROD) is calculated by replacing DQE by the generalized DQE (GDQE) which includes geometric unsharpness and scatter to evaluate the total imaging chain. The G-ROD was calculated for the micro-angiographic fluoroscope (MAF) relative to a flat-panel detector (FPD) for low (1.05) and high (1.2) magnifications with two focal-spot sizes, small (0.3 mm) and medium (0.5 mm), and for the same value of scatter fraction. Solid spheres from 50 to 600 microns were simulated as the objects for this evaluation. The G-ROD results were compared with those of the ROD which considers the detectors alone. Results: For 50-micron spheres, the ROD is 7.93 and, for the small [medium] focus, the G-ROD is 6.74 [5.22] at low magnification and 3.03 [1.66] at high magnification, indicating superior performance of the MAF particularly at low magnification. Both ROD and G-ROD decrease monotonically with size and remain around one above 400-microns. The G-ROD decreases more dramatically with low compared to high magnification for both focal spots. Conclusion: In all cases, the MAF performs better than the FPD and the decreasing trend of the G-ROD indicates that the performance of both detectors becomes similar as the object size increases and becomes nearly equal above 400-micron diameter sphere size. Finally, increased magnification and focal-spot size decrease the G-ROD, indicting that they degrade the performance of the MAF more than that of the FPD for a small-object viewing task. Supported by NIH Grant: 2R01EB002873 and an equipment grant from

  5. Rod Photoreceptor Differentiation in Fetal and Infant Human Retina

    PubMed Central

    Hendrickson, Anita; Bumsted-O'Brien, Keely; Natoli, Riccardo; Ramamurthy, Visvanathan; Possin, Daniel; Provis, Jan

    2014-01-01

    Human rods and cones are arranged in a precise spatial mosaic that is critical for optimal functioning of the visual system. However, the molecular processes that underpin specification of cell types within the mosaic are poorly understood. The progressive differentiation of human rods was tracked from fetal week (Fwk) 9 to postnatal (P) 8 months using immunocytochemical markers of key molecules that represent rod progression from post-mitotic precursors to outer segment-bearing functional photoreceptors. We find two phases associated with rod differentiation. The early phase begins in rods on the foveal edge at Fwk 10.5 when rods are first identified, and the rod-specific proteins NRL and NR2e3 are detected. By Fwk 11-12, these rods label for interphotoreceptor retinoid binding protein, recoverin, and aryl hydrocarbon receptor interacting protein-like 1. The second phase occurs over the next month with the appearance of rod opsin at Fwk 15, closely followed by the outer segment proteins rod GTP-gated sodium channel and peripherin. TULP is expressed relatively late at Fwk 18-20 in rods. Each phase proceeds across the retina in a central-peripheral order, such that rods in far peripheral retina are only entering the early phase at the same time that cells in central retina are entering their late phase. During the second half of gestation rods undergo an intracellular reorganization of these proteins, and cellular and OS elongation which continues into infancy. The progression of rod development shown here provides insight into the possible mechanisms underlying human retinal visual dysfunction when there are mutations affecting key rod-related molecules. PMID:18778702

  6. Transport properties of rigid bent-rod macromolecules and of semiflexible broken rods in the rigid-body treatment. Analysis of the flexibility of myosin rod.

    PubMed Central

    Iniesta, A; Díaz, F G; García de la Torre, J

    1988-01-01

    The translational diffusion coefficients, rotational relaxation times and intrinsic viscosities of rigid bent rods, composed by two rodlike arms joined rigidly at an angle alpha, have been evaluated for varying conformation using the latest advances in hydrodynamic theory. We have considered semiflexible rods in which the joint is an elastic hinge or swivel, with a potential V(alpha) = 1/2Q alpha 2 with constant Q. Accepting the rigid-body treatment, we calculate properties of broken rods by averaging alpha-dependent values for rigid rods. The results are finally used to interpret literature values of the properties of myosin rod. Q is regarded as an adjustable parameter, and the value fitted is such that the average bending angle of myosin rod is approximately 60 degrees. PMID:3207825

  7. 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.

  8. Diffusion of a nanowire rod through an obstacle field

    NASA Astrophysics Data System (ADS)

    Kasimov, Dror; Admon, Tamir; Roichman, Yael

    2016-05-01

    We report the experimental realization of a rod diffusing in a two-dimensional obstacle field following the single rod dynamics. We use a silver nanowire as our rod and two types of obstacles: repelling light beams and polymer pillars. We study the effect of hydrodynamic interactions on the transport of the rod, comparing both experimental realizations and recent simulations. We propose a framework for analyzing the transport through such systems, and we predict a new superdiffusive regime of rod transport at high obstacle concentration and short times.

  9. 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

  10. Sealing system for piston rod of hot gas engine

    SciTech Connect

    Lundholm, S.G.; Ringqvist, S.A.

    1980-11-25

    An improvement to a sealing system for restricting fluid flow around a piston rod between a piston cylinder and crankshaft space in a hot gas engine where a seal element is secured around the piston rod in an intermediate chamber, the improvement including a link in the crankshaft space connecting, and permitting relative radial motion between, the piston rod and the crosshead and an o-ring having a diameter substantially greater than that of the piston rod and being secured between a lower ring securing the seal element in place around the piston rod and a wall of the intermediate chamber for frictionally restricting radial movement of the lower ring.

  11. System performance advances of 18-mm and 16-mm subminiature image intensifier sensors

    NASA Astrophysics Data System (ADS)

    Thomas, Nils I.

    2000-11-01

    Night vision system design has been centered aroudn the An/AVS-6 and AN/PVS-7 night vision goggle systems for the past 20 years. Goggle performance has improved during this time through increased performance of the image intensifier sensor, primarily the Omni IV sensor from ITT Industries Night Vision. Most of this improvement has been at the optimal light level (1E-3 fc scene illumination). Recent advances in image sensor performance from the filmless Generation (Gen) IV sensors has increased the low light level performance of night vision devices from 0.3 cy/mr to 0.7 cy/mr. In addition, sensor packaging design requirements have forced night vision sensor manufactures to design light weight, small volume sensors. ITT recently has designed such a sensor in a 16-mm format. This sensor if 50% lighter, up to 50% shorter, and has design features that simplify the objective lens design. New night vision goggles have been, and are being, designed which reduce the perceived head-supported weight. This paper presents signal-to-noise ratio, halo, and other film-less sensor data and similar 16-mm subminiature sensor data. The resulting system performance data will be described. Finally, the system design improvements and relationships with the subminiature 16-mm subminiature sensor will be given.

  12. Dynamics of gas-fluidized granular rods.

    PubMed

    Daniels, L J; Park, Y; Lubensky, T C; Durian, D J

    2009-04-01

    We study a quasi-two-dimensional monolayer of granular rods fluidized by a spatially and temporally homogeneous upflow of air. By tracking the position and orientation of the particles, we characterize the dynamics of the system with sufficient resolution to observe ballistic motion at the shortest time scales. Particle anisotropy gives rise to dynamical anisotropy and superdiffusive dynamics parallel to the rod's long axis, causing the parallel and perpendicular mean-square displacements to become diffusive on different time scales. The distributions of free times and free paths between collisions deviate from exponential behavior, underscoring the nonthermal character of the particle motion. The dynamics show evidence of rotational-translational coupling similar to that of an anisotropic Brownian particle. We model rotational-translational coupling in the single-particle dynamics with a modified Langevin model using nonthermal noise sources. This suggests a phenomenological approach to thinking about collections of self-propelling particles in terms of enhanced memory effects. PMID:19518218

  13. Rod influence in dichromatic surface color perception.

    PubMed

    Montag, E D; Boynton, R M

    1987-01-01

    Two protanopes, two deuteranopes, and two normal subjects named 424 OSA Uniform Color Scales samples using single-word color terms of their choice under three different experimental conditions. When viewing a stimulus field subtending about 4 deg, the performance of the dichromats revealed a substantial ability to discriminate colors along the red-green axis. When the stimuli were limited to the central fovea, or when rods were excluded with a bleach, dichromats could no longer categorize colors in the red-green dimension. The different conditions did not affect the performance of the normals. The results suggest that rods contribute signals used by dichromats, along with lightness cues, to help discriminate and categorize surface colors. PMID:3502300

  14. Oil well sucker rod safety block

    SciTech Connect

    McDaniel, D. L.

    1984-11-20

    A fail-safe knock-off block for use during the repair or servicing of oil well surface pumping equipment involving a longitudinally slotted pipe capped at each end by top and bottom pipe segments which are held in place concentric to the slotted pipe by a resilient handle. An inner handle on the slotted pipe allows the concentric caps to be rotated axially from an open position to a closed position, thus encircling the polish rod. The weight of the sucker rod string on the end caps during use compresses the end caps and resilient handle thus locking the safety block such that it can neither open nor come off the well head.

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

    PubMed

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

    2013-09-01

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

  16. 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.

  17. Nuclear reactor fuel rod attachment system

    DOEpatents

    Christiansen, David W.

    1982-01-01

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

  18. Intranuclear rods myopathy with autonomic dysfunction.

    PubMed

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

    2013-08-01

    Intranuclear rods myopathy (IRM), a variant of nemaline myopathy (NM), is characterized by rod structure in the myonuclei. Patients with IRM present with similar symptoms to those of severe infantile-type NM but have worse outcome. Several extramuscular manifestations have been reported in NM but no dysautonomia. We herein report a 2-year-old girl with IRM and a heterozygous mutation, c.430C>T (p.L144F) in ACTA1. During the infancy, the patient showed severe diaphoresis and facial flushing. Arrhythmia and hypertension with the precipitating factors of feeding, defecation, and urination were observed. Sympathetic antagonist was prescribed and showed some effectiveness. Our report may widen the clinical spectrum of IRM. It also reminds clinicians that autonomic dysfunction may occur in patients with IRM or other actinopathies and appropriate treatment may be necessary. PMID:23102861

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

    PubMed

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

    2013-09-01

    Symbolism is one of the most archaic forms of human thoughts. Symbol derives from the Latin word symbolum, and the latter from the Greek symbolon or symballo, which means "I coincide, I make matches". The Medicine symbol represents a whole series of historical and ethical values. Asclepius Rod with one serpent entwined, has traditionally been the symbol of scientific medicine. In a misconception that has lasted 500 years, the Caduceus of Hermes, entwined by two serpents and with two wings, has been considered the symbol of Medicine. However, the Caduceus is the current symbol of Commerce. Asclepius Rod and the Caduceus of Hermes represent two professions, Medicine and Commerce that, in ethical practice, should not be mixed. Physicians should be aware of their real emblem, its historical origin and meaning. PMID:24522424

  20. Fluid Dynamics in Sucker Rod Pumps

    SciTech Connect

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

    1999-01-14

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

  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. On the perfect hexagonal packing of rods

    NASA Astrophysics Data System (ADS)

    Starostin, E. L.

    2006-04-01

    In most cases the hexagonal packing of fibrous structures or rods extremizes the energy of interaction between strands. If the strands are not straight, then it is still possible to form a perfect hexatic bundle. Conditions under which the perfect hexagonal packing of curved tubular structures may exist are formulated. Particular attention is given to closed or cycled arrangements of the rods like in the DNA toroids and spools. The closure or return constraints of the bundle result in an allowable group of automorphisms of the cross-sectional hexagonal lattice. The structure of this group is explored. Examples of open helical-like and closed toroidal-like bundles are presented. An expression for the elastic energy of a perfectly packed bundle of thin elastic rods is derived. The energy accounts for both the bending and torsional stiffnesses of the rods. It is shown that equilibria of the bundle correspond to solutions of a variational problem formulated for the curve representing the axis of the bundle. The functional involves a function of the squared curvature under the constraints on the total torsion and the length. The Euler-Lagrange equations are obtained in terms of curvature and torsion and due to the existence of the first integrals the problem is reduced to the quadrature. The three-dimensional shape of the bundle may be readily reconstructed by integration of the Ilyukhin-type equations in special cylindrical coordinates. The results are of universal nature and are applicable to various fibrous structures, in particular, to intramolecular liquid crystals formed by DNA condensed in toroids or packed inside the viral capsids. International Workshop on Biopolymers: Thermodynamics, Kinetics and Mechanics of DNA, RNA and Proteins, 30.05.2005-3.06.2005, The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy.

  3. Rod Driven Frequency Entrainment and Resonance Phenomena

    PubMed Central

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

    2016-01-01

    A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α) of each volunteer in the range from 0.40 to 2.30∗α. Three hundred and six-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90–1.10∗α) and half of the alpha frequency (0.40–0.55∗α). No signs of resonance and frequency entrainment phenomena were revealed around 2.00∗α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30–2.30∗α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex. PMID:27588002

  4. Rod Driven Frequency Entrainment and Resonance Phenomena.

    PubMed

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

    2016-01-01

    A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α) of each volunteer in the range from 0.40 to 2.30(∗)α. Three hundred and six-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90-1.10(∗)α) and half of the alpha frequency (0.40-0.55(∗)α). No signs of resonance and frequency entrainment phenomena were revealed around 2.00(∗)α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30-2.30(∗)α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex. PMID:27588002

  5. Smectic filaments in colloidal suspensions of rods.

    PubMed

    Frenkel, Daan; Schilling, Tanja

    2002-10-01

    In supersaturated isotropic mixtures of hard rods, smectic filaments have recently been observed. We propose a model for formation and growth of these filaments similar to the Hoffman-Lauritzen model for polymer crystallization. Filament thickness is determined by a compromise between maximizing the amount of smectic phase formed and minimizing the nucleation barrier for adding new segments to the growing filament. We compare our analytical results to kinetic Monte Carlo simulations.

  6. Development of a fuel-rod simulator and small-diameter thermocouples for high-temperature, high-heat-flux tests in the Gas-Cooled Fast Reactor Core Flow Test Loop

    SciTech Connect

    McCulloch, R.W.; MacPherson, R.E.

    1983-03-01

    The Core Flow Test Loop was constructed to perform many of the safety, core design, and mechanical interaction tests in support of the Gas-Cooled Fast Reactor (GCFR) using electrically heated fuel rod simulators (FRSs). Operation includes many off-normal or postulated accident sequences including transient, high-power, and high-temperature operation. The FRS was developed to survive: (1) hundreds of hours of operation at 200 W/cm/sup 2/, 1000/sup 0/C cladding temperature, and (2) 40 h at 40 W/cm/sup 2/, 1200/sup 0/C cladding temperature. Six 0.5-mm type K sheathed thermocouples were placed inside the FRS cladding to measure steady-state and transient temperatures through clad melting at 1370/sup 0/C.

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

    PubMed Central

    Arden, G B; Hogg, C R

    1985-01-01

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

  8. Modeling the Flexural Rigidity of Rod Photoreceptors

    PubMed Central

    Haeri, Mohammad; Knox, Barry E.; Ahmadi, Aphrodite

    2013-01-01

    In vertebrate eyes, the rod photoreceptor has a modified cilium with an extended cylindrical structure specialized for phototransduction called the outer segment (OS). The OS has numerous stacked membrane disks and can bend or break when subjected to mechanical forces. The OS exhibits axial structural variation, with extended bands composed of a few hundred membrane disks whose thickness is diurnally modulated. Using high-resolution confocal microscopy, we have observed OS flexing and disruption in live transgenic Xenopus rods. Based on the experimental observations, we introduce a coarse-grained model of OS mechanical rigidity using elasticity theory, representing the axial OS banding explicitly via a spring-bead model. We calculate a bending stiffness of ∼105 nN⋅μm2, which is seven orders-of-magnitude larger than that of typical cilia and flagella. This bending stiffness has a quadratic relation to OS radius, so that thinner OS have lower fragility. Furthermore, we find that increasing the spatial frequency of axial OS banding decreases OS rigidity, reducing its fragility. Moreover, the model predicts a tendency for OS to break in bands with higher spring number density, analogous to the experimental observation that transgenic rods tended to break preferentially in bands of high fluorescence. We discuss how pathological alterations of disk membrane properties by mutant proteins may lead to increased OS rigidity and thus increased breakage, ultimately contributing to retinal degeneration. PMID:23442852

  9. 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.

  10. Incorporation of squalene into rod outer segments

    SciTech Connect

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

    1990-08-15

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

  11. TEM00 mode Nd:YAG solar laser by side-pumping a grooved rod

    NASA Astrophysics Data System (ADS)

    Vistas, Cláudia R.; Liang, Dawei; Almeida, Joana; Guillot, Emmanuel

    2016-05-01

    A simple TEM00 mode solar laser system with a grooved Nd:YAG rod pumped through a heliostat-parabolic mirror system is reported here. The radiation coupling capacity of a fused silica tube lens was combined with the multipass pumping ability of a 2 V-shaped cavity to provide efficient side-pumping along a 4.0 mm diameter grooved Nd:YAG single-crystal rod. TEM00 mode solar laser power of 3.4 W was measured by adopting an asymmetric large-mode laser resonant cavity. Record TEM00 mode solar laser collection efficiency of 3.4 W/m2and slope efficiency of 1.9% was achieved, which corresponds to 1.8 and 2.4 times more than the previous TEM00 mode Nd:YAG solar laser using the PROMES-CNRS heliostat-parabolic mirror system, respectively.

  12. Between a Map and a Data Rod

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  13. Between a Map and a Data Rod

    NASA Astrophysics Data System (ADS)

    Teng, W. L.; Rui, H.; Strub, R. F.; Vollmer, B.

    2015-12-01

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

  14. Spherical Joint Piston and Connecting Rod Developed

    NASA Technical Reports Server (NTRS)

    1996-01-01

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

  15. Biomechanical study of the sacroiliac fracture fixation with titanium rods and pedicle screws

    PubMed Central

    Ueno, Fabrício Hidetoshi; Pisani, Marina Justi; Machado, André Nunes; Rodrigues, Fábio Lucas; Fujiki, Edison Noburo; Rodrigues, Luciano Miller Reis

    2015-01-01

    OBJECTIVES: To assess biomechanically different fixations means of the sacroiliac joint with pedicle screws and to compare the traditional head height with reduced ones. METHODS: We used a polyethylene model representing the pelvic ring and simulated a unilateral sacroiliac dislocation. We set up three different constructions: 1) two screws attached to a rod; 2) two rods connected to two small head screws each; and 3) two rods connected to two average headed screws each. We conducted tests in a biomechanical testing and a mechanized processing laboratory. RESULTS: Group 1 supported an average maximum load of 99.70 N. Group 2 supported an average maximum load of 362.46 N. Group 3 endured an average maximum load of 404.15 N. In the assembly with one rod, the resistance decreased as compared with the one with two bars: 72.5 % compared to small-headed screws and 75.3 % to the traditional screw. CONCLUSION: The assembly with a single bar presented inferior results when compared to the double bar assembly. There was no statistical difference in the results between the screws used. Experimental Study. PMID:26207094

  16. Adjustable Permanent Quadrupoles Using Rotating Magnet Material Rods for the Next Linear Collider

    SciTech Connect

    James T Volk et al.

    2001-09-24

    The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 132 Tesla, with a maximum gradient of 135 Tesla per meter, an adjustment range of +0-20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micrometer during the 20% adjustment. In an effort to reduce estimated costs and increase reliability, several designs using hybrid permanent magnets have been developed. All magnets have iron poles and use either Samarium Cobalt or Neodymium Iron to provide the magnetic fields. Two prototypes use rotating rods containing permanent magnetic material to vary the gradient. Gradient changes of 20% and center shifts of less than 20 microns have been measured. These data are compared to an equivalent electromagnet prototype.

  17. Determination of the rod-wire transition length in colloidal indium phosphide quantum rods.

    PubMed

    Wang, Fudong; Buhro, William E

    2007-11-21

    Colloidal InP quantum rods (QRs) having controlled diameters and lengths are grown by the solution-liquid-solid method, from Bi nanoparticles in the presence of hexadecylamine and other conventional quantum dot surfactants. These quantum rods show band-edge photoluminescence after HF photochemical etching. Photoluminescence efficiency is further enhanced after the Bi tips are selectively removed from the QRs by oleic acid etching. The QRs are anisotropically 3D confined, the nature of which is compared to the corresponding isotropic 3D confinement in quantum dots and 2D confinement in quantum wires. The 3D-2D rod-wire transition length is experimentally determined to be 25 nm, which is about 2 times the bulk InP exciton Bohr radius (of approximately 11 nm).

  18. Feedback from horizontal cells to rod photoreceptors in vertebrate retina

    PubMed Central

    Thoreson, Wallace B.; Babai, Norbert; Bartoletti, Theodore M.

    2013-01-01

    Retinal horizontal cells (HCs) provide negative feedback to cones but, largely because annular illumination fails to evoke a depolarizing response in rods, it is widely believed that there is no feedback from HCs to rods. However, feedback from HCs to cones involves small changes in the calcium current (ICa) that does not always generate detectable depolarizing responses. We therefore recorded ICa directly from rods to test whether they were modulated by feedback from HCs. To circumvent problems presented by overlapping receptive fields of HCs and rods, we manipulated the membrane potential of voltage clamped HCs while simultaneously recording from rods in a salamander retinal slice preparation. Like HC feedback in cones, hyperpolarizing HCs from −14 to −54, −84, and −104 mV increased the amplitude of ICa recorded from synaptically connected rods and caused hyperpolarizing shifts in ICa voltage dependence. These effects were blocked by supplementing the bicarbonate-buffered saline solution with HEPES. In rods lacking light-responsive outer segments, hyperpolarizing neighboring HCs with light caused a negative activation shift and increased the amplitude of ICa. These changes in ICa were blocked by HEPES and by inhibiting HC light responses with a glutamate antagonist indicating they were due to HC feedback. These results show that rods, like cones, receive negative feedback from HCs that regulates the amplitude and voltage dependence of ICa. HC to rod feedback counters light-evoked decreases in synaptic output and thus shapes the transmission of rod responses to downstream visual neurons. PMID:18509030

  19. 1. East portal of Tunnel 3, view to west, 135mm ...

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

    1. East portal of Tunnel 3, view to west, 135mm lens. This tunnel was photographed to provide context, because even though somewhat enlarged, it illustrates the nature of the unlined hard rock tunnels typical of the original Central Pacific construction in 1868. - Central Pacific Transcontinental Railroad, Tunnel No. 3, Milepost 180.65, Cisco, Placer County, CA

  20. A computational biomechanical investigation of posterior dynamic instrumentation: combination of dynamic rod and hinged (dynamic) screw.

    PubMed

    Erbulut, Deniz U; Kiapour, Ali; Oktenoglu, Tunc; Ozer, Ali F; Goel, Vijay K

    2014-05-01

    Currently, rigid fixation systems are the gold standard for degenerative disk disease treatment. Dynamic fixation systems have been proposed as alternatives for the treatment of a variety of spinal disorders. These systems address the main drawbacks of traditional rigid fixation systems, such as adjacent segment degeneration and instrumentation failure. Pedicle-screw-based dynamic stabilization (PDS) is one type of these alternative systems. The aim of this study was to simulate the biomechanical effect of a novel posterior dynamic stabilization system, which is comprised of dynamic (hinged) screws interconnected with a coiled, spring-based dynamic rod (DSDR), and compare it to semirigid (DSRR and RSRR) and rigid stabilization (RSRR) systems. A validated finite element (FE) model of L1-S1 was used to quantify the biomechanical parameters of the spine, such as range of motion, intradiskal pressure, stresses and facet loads after single-level instrumentation with different posterior stabilization systems. The results obtained from in vitro experimental intact and instrumented spines were used to validate the FE model, and the validated model was then used to compare the biomechanical effects of different fixation and stabilization constructs with intact under a hybrid loading protocol. The segmental motion at L4-L5 increased by 9.5% and 16.3% in flexion and left rotation, respectively, in DSDR with respect to the intact spine, whereas it was reduced by 6.4% and 10.9% in extension and left-bending loads, respectively. After instrumentation-induced intradiskal pressure at adjacent segments, L3-L4 and L5-S1 became less than the intact in dynamic rod constructs (DSDR and RSDR) except in the RSDR model in extension where the motion was higher than intact by 9.7% at L3-L4 and 11.3% at L5-S1. The facet loads were insignificant, not exceeding 12N in any of the instrumented cases in flexion. In extension, the facet load in DSDR case was similar to that in intact spine. The

  1. Teaching Evolutionary Mechanisms: Genetic Drift and M&M's.

    ERIC Educational Resources Information Center

    Staub, Nancy L.

    2002-01-01

    Describes a classroom activity that teaches the mechanism of genetic drift to undergraduates. Illustrates a number of concepts that are critical in developing evolution literacy by sampling M&M milk chocolate candies. (MM)

  2. Evaluation of Computed Tomography of Mock Uranium Fuel Rods at the Advanced Photon Source

    DOE PAGES

    Hunter, James F.; Brown, Donald William; Okuniewski, Maria

    2015-06-01

    This study discusses a multi-year effort to evaluate the utility of computed tomography at the Advanced Photon Source (APS) as a tool for non-destructive evaluation of uranium based fuel rods. The majority of the data presented is on mock material made with depleted uranium which mimics the x-ray attenuation characteristics of fuel rods while allowing for simpler handling. A range of data is presented including full thickness (5mm diameter) fuel rodlets, reduced thickness (1.8mm) sintering test samples, and pre/post irradiation samples (< 1mm thick). These data were taken on both a white beam (bending magnet) beamline and a high energy,more » monochromatic beamline. This data shows the utility of a synchrotron type source in the evealuation of manufacturing defects (pre-irradiation) and lays out the case for in situ CT of fuel pellet sintering. Finally, in addition data is shown from small post-irradiation samples and a case is made for post-irradiation CT of larger samples.« less

  3. Evaluation of Computed Tomography of Mock Uranium Fuel Rods at the Advanced Photon Source

    SciTech Connect

    Hunter, James F.; Brown, Donald William; Okuniewski, Maria

    2015-06-01

    This study discusses a multi-year effort to evaluate the utility of computed tomography at the Advanced Photon Source (APS) as a tool for non-destructive evaluation of uranium based fuel rods. The majority of the data presented is on mock material made with depleted uranium which mimics the x-ray attenuation characteristics of fuel rods while allowing for simpler handling. A range of data is presented including full thickness (5mm diameter) fuel rodlets, reduced thickness (1.8mm) sintering test samples, and pre/post irradiation samples (< 1mm thick). These data were taken on both a white beam (bending magnet) beamline and a high energy, monochromatic beamline. This data shows the utility of a synchrotron type source in the evealuation of manufacturing defects (pre-irradiation) and lays out the case for in situ CT of fuel pellet sintering. Finally, in addition data is shown from small post-irradiation samples and a case is made for post-irradiation CT of larger samples.

  4. High-precision measurements of wetland sediment elevation. II The rod surface elevation table

    USGS Publications Warehouse

    Cahoon, D.R.; Lynch, J.C.; Perez, B.C.; Segura, B.; Holland, R.D.; Stelly, C.; Stephenson, G.; Hensel, P.

    2002-01-01

    A new high-precision device for measuring sediment elevation in emergent and shallow water wetland systems is described. The rod surface-elevation table (RSET) is a balanced, lightweight mechanical leveling device that attaches to both shallow ( 1 m in order to be stable. The pipe is driven to refusal but typically to a depth shallower than the rod bench mark because of greater surface resistance of the pipe. Thus, the RSET makes it possible to partition change in sediment elevation over shallower (e.g., the root zone) and deeper depths of the sediment profile than is possible with the SET. The confidence intervals for the height of an individual pin measured by two different operators with the RSET under laboratory conditions were A? 1.0 and A? 1.5 mm. Under field conditions, confidence intervals for the measured height of an individual pin ranged from A? 1.3 mm in a mangrove forest up to A? 4.3 mm in a salt marsh.

  5. 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)

  6. Gas Interference in Sucker Rod Pump

    NASA Astrophysics Data System (ADS)

    Samad, Abdus

    2010-10-01

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

  7. Rodded shutdown system for a nuclear reactor

    DOEpatents

    Golden, Martin P.; Govi, Aldo R.

    1978-01-01

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

  8. Nonelastomeric Rod Seals for Advanced Hydraulic Systems

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  9. Rod-like nano-light harvester.

    PubMed

    Ling, Jun; Zheng, Zhicheng; Köhler, Anna; Müller, Axel H E

    2014-01-01

    Imitating the natural "energy cascade" architecture, we present a single-molecular rod-like nano-light harvester (NLH) based on a cylindrical polymer brush. Block copolymer side chains carrying (9,9-diethylfluoren-2-yl)methyl methacrylate units as light absorbing antennae (energy donors) are tethered to a linear polymer backbone containing 9-anthracenemethyl methacrylate units as emitting groups (energy acceptors). These NLHs exhibit very efficient energy absorption and transfer. Moreover, we manipulate the energy transfer by tuning the donor-acceptor distance.

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

    PubMed

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

    2016-08-21

    The equilibrium properties of hard rod monolayers are investigated in a lattice model (where position and orientation of a rod are restricted to discrete values) as well as in an off-lattice model featuring spherocylinders with continuous positional and orientational degrees of freedom. Both models are treated using density functional theory and Monte Carlo simulations. Upon increasing the density of rods in the monolayer, there is a continuous ordering of the rods along the monolayer normal ("standing up" transition). The continuous transition also persists in the case of an external potential which favors flat-lying rods in the monolayer. This behavior is found in both the lattice and the continuum models. For the lattice model, we find very good agreement between the results from the specific DFT used (lattice fundamental measure theory) and simulations. The properties of lattice fundamental measure theory are further illustrated by the phase diagrams of bulk hard rods in two and three dimensions. PMID:27544121

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

    SciTech Connect

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

    1993-09-01

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

  12. Fiberglass sucker rods - a futuristic solution to today's problem wells

    SciTech Connect

    Treadway, R.B.; Focazio, K.R.

    1981-01-01

    A new fiberglass sucker rod design was developed, which incorporated many new and major modifications to correct the problems that had plagued the previous rod. This paper documents the success of these rods in depths ranging from 5,000'-10,000', and production ranges of 150 - 700 barrels of fluid per day. In addition, Amoco had also installed over fifty strings of fiberglass rods in their other four West Texas and Eastern New Mexico districts, and several are being evaluated in East Texas and on the Gulf Coast. At the present time, all of these additional installations show the same success as those reported in this paper. The changes in the manufacturing process, the use of a computer program for performance prediction, and the development of a new load range diagram are also discussed. Final data indicate that, when designed and installed properly, fiberglass sucker rods are a viable, economic, and often preferable alternative to steel sucker rods.

  13. Convergent synthesis of multiporphyrin light-harvesting rods

    DOEpatents

    Lindsey, Jonathan S.; Loewe, Robert S.

    2003-08-05

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

  14. Vibration of the Package of Rods Linked by Spacer Grids

    NASA Astrophysics Data System (ADS)

    Zeman, V.; Hlaváč, Z.

    This paper deals with modelling and vibration analysis of the large package of identical parallel rods which are linked by transverse springs (spacer grids) placed on several level spacings. The vibration of rods is caused by the support plate motion. The rod discretization by FEM is based on Rayleigh beam theory. With respect to cyclic and central package rod symmetry, the system is decomposed to identical revolved rod segments. The modal synthesis method with condensation of the rod segments is used for modelling and determination of steady forced vibration of the whole system. The presented method is the first step to modelling of the nuclear fuel assembly vibration caused by kinematical excitation determined by motion of the support plates which are part of the reactor core.

  15. Sporadic Creutzfeldt-Jakob Disease MM1+2C and MM1 are Identical in Transmission Properties.

    PubMed

    Kobayashi, Atsushi; Matsuura, Yuichi; Iwaki, Toru; Iwasaki, Yasushi; Yoshida, Mari; Takahashi, Hitoshi; Murayama, Shigeo; Takao, Masaki; Kato, Shinsuke; Yamada, Masahito; Mohri, Shirou; Kitamoto, Tetsuyuki

    2016-01-01

    The genotype (methionine, M or valine, V) at polymorphic codon 129 of the PRNP gene and the type (1 or 2) of abnormal prion protein in the brain are the major determinants of the clinicopathological features of sporadic Creutzfeldt-Jakob disease (CJD), thus providing molecular basis for classification of sporadic CJD, that is, MM1, MM2, MV1, MV2, VV1 or VV2. In addition to these "pure" cases, "mixed" cases presenting mixed neuropathological and biochemical features have also been recognized. The most frequently observed mixed form is the co-occurrence of MM1 and MM2, namely MM1+2. However, it has remained elusive whether MM1+2 could be a causative origin of dura mater graft-associated CJD (dCJD), one of the largest subgroups of iatrogenic CJD. To test this possibility, we performed transmission experiments of MM1+2 prions and a systematic neuropathological examination of dCJD patients in the present study. The transmission properties of the MM1+2 prions were identical to those of MM1 prions because MM2 prions lacked transmissibility. In addition, the neuropathological characteristics of MM2 were totally absent in dCJD patients examined. These results suggest that MM1+2 can be a causative origin of dCJD and causes neuropathological phenotype similar to that of MM1.

  16. Phase behavior of a suspension of colloidal hard rods and nonadsorbing polymer.

    PubMed

    Savenko, S V; Dijkstra, Marjolein

    2006-06-21

    We study the phase behavior of a mixture of colloidal hard rods with a length-to-diameter ratio of L/sigma(c)=5 and nonadsorbing ideal polymer. We map our binary mixture onto an effective one-component system by integrating out the degrees of freedom of the polymer coils. We derive a formal expression for the exact effective Hamiltonian of the colloidal rods, i.e., it includes all effective many-body interactions and it is related to the exact free volume available for the polymer. We determine numerically on a grid the free volume available for the ideal polymer coils "on the fly" for each colloidal rod configuration during our Monte Carlo simulations. This allows us to go beyond first-order perturbation theory, which employs the pure hard-rod system as reference state. We perform free energy calculations for the isotropic, nematic, smectic, and crystal phase using thermodynamic integration and common tangent constructions are used at fixed polymer fugacities to map out the phase diagram. The phase behavior is determined for size ratios q=sigma(p)/sigma(c)=0.15, 0.5, and 1, where sigma(p) is the diameter of the polymer coils. The phase diagrams based on the full effective Hamiltonian are compared with those obtained from first-order perturbation theory, from simulations using the effective pair potential approximation to the effective Hamiltonian, and with those based on an empiric effective depletion potential for the rods. We find that the many-body character of the effective interactions stabilizes the nematic and smectic phases for large q, while the effective pair potential description overestimates the attractive interactions and favors, hence, a broad isotropic-crystal coexistence. PMID:16821948

  17. COMPUTER MODEL OF TEMPERATURE DISTRIBUTION IN OPTICALLY PUMPED LASER RODS

    NASA Technical Reports Server (NTRS)

    Farrukh, U. O.

    1994-01-01

    Managing the thermal energy that accumulates within a solid-state laser material under active pumping is of critical importance in the design of laser systems. Earlier models that calculated the temperature distribution in laser rods were single dimensional and assumed laser rods of infinite length. This program presents a new model which solves the temperature distribution problem for finite dimensional laser rods and calculates both the radial and axial components of temperature distribution in these rods. The modeled rod is either side-pumped or end-pumped by a continuous or a single pulse pump beam. (At the present time, the model cannot handle a multiple pulsed pump source.) The optical axis is assumed to be along the axis of the rod. The program also assumes that it is possible to cool different surfaces of the rod at different rates. The user defines the laser rod material characteristics, determines the types of cooling and pumping to be modeled, and selects the time frame desired via the input file. The program contains several self checking schemes to prevent overwriting memory blocks and to provide simple tracing of information in case of trouble. Output for the program consists of 1) an echo of the input file, 2) diffusion properties, radius and length, and time for each data block, 3) the radial increments from the center of the laser rod to the outer edge of the laser rod, and 4) the axial increments from the front of the laser rod to the other end of the rod. This program was written in Microsoft FORTRAN77 and implemented on a Tandon AT with a 287 math coprocessor. The program can also run on a VAX 750 mini-computer. It has a memory requirement of about 147 KB and was developed in 1989.

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

    SciTech Connect

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

    1992-08-01

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

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

    SciTech Connect

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

    1992-01-01

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

  20. Penetration of a copper rod into a sandy target

    NASA Astrophysics Data System (ADS)

    Kaminskii, M. V.; Kopytov, G. F.; Mogilev, V. A.; Travov, Yu. F.; Faikov, Yu. I.

    2010-05-01

    This paper presents the results of experimental and theoretical studies of high-velocity penetration of cylindrical copper rods into sand. The hydrodynamic Alekseevskii-Tate theory is modified to determine the penetration depth and wear velocity of the material of the rod penetrating into soil target in the plastic and hydrodynamic stages of penetration. The case where the target material is significantly less strong than the rod (impactor) material is considered.

  1. Penetration of tungsten-alloy rods into composite ceramic targets: Experiments and 2-D simulations

    SciTech Connect

    Rosenberg, Z.; Dekel, E.; Hohler, V.; Stilp, A. J.; Weber, K.

    1998-07-10

    A series of terminal ballistics experiments, with scaled tungsten-alloy penetrators, was performed on composite targets consisting of ceramic tiles glued to thick steel backing plates. Tiles of silicon-carbide, aluminum nitride, titanium-dibroide and boron-carbide were 20-80 mm thick, and impact velocity was 1.7 km/s. 2-D numerical simulations, using the PISCES code, were performed in order to simulate these shots. It is shown that a simplified version of the Johnson-Holmquist failure model can account for the penetration depths of the rods but is not enough to capture the effect of lateral release waves on these penetrations.

  2. Biophysical mechanism of transient retinal phototropism in rod photoreceptors

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    NASA Technical Reports Server (NTRS)

    Leone, Frank A., Jr.

    2016-01-01

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

  4. Transient elastic impact response of slender graphite rods

    SciTech Connect

    Erdem, I.

    2007-12-15

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

  5. Viscoelasticity of Solutions of Semiflexible Rods

    NASA Astrophysics Data System (ADS)

    Morse, David

    2001-03-01

    I will discuss theoretical studies and Brownian dynamics simulationsof the linear viscoelasticity of solutions of wormlike chains. The relaxation modulus G(t) in dilute solutions of relatively short chains, with lengths L less than the persistence length L_p, is found to exhibit three time regimes: At very early times, before an initially affine longitudinal deformation has begun to relax, G(t) ∝ t-3/4. Over a broad range of intermediate times, during which the end-to-end length relaxes, G(t) ∝ t-5/4. In these first two regimes, the stress is dominated by longitudinal forces (i.e., tension) induced by the deformation. At long times, G(t) mimics the exponential decay found for solutions of rods, due to the rotational diffusion of the overall chain orientation. An analytically solvable model of the mechanically inextensible semiflexible chain as an effectively extensible rod, with an effective modulus B(ω) ∝ ω^3/4, is shown to quantitatively describe G(t) for all L <= Lp throughout the first two time regimes. In tightly-entangled solutions, a additional plateau in G(t) appears, in which the stress is dominated by transverse forces, due to stress arising from the disturbance of the equilibrium distribution of transverse fluctuations, which, in this regime, can relax only by reptation. Predictions are compared to experiments with dilute solutions of poly(benzyl glutamate) and tightly-entangled solutions of F-actin.

  6. Laser decontamination of the radioactive lightning rods

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  7. Analysis of sucker rod and sinkerbar failures

    SciTech Connect

    Waggoner, J.R.; Buchheit, R.G.

    1992-12-31

    This paper presents results from a study to analyze the performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, structural finite element analysis, and detailed failure data collection. Metallography demonstrated that microstructure of steel bar stock needs to be considered. Current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding. Finite element analysis of the threaded connection identifies stress and fatigue concentrations and quantitatively assesses the performance and failure of coupling designs under a variety of loading conditions. Subcritical fractures observed in the metallography are also suggested by the calculated stress distribution in the threaded coupling. Failure data illustrates both magnitude and frequency of the failures, as well as categorizing the suspected cause of failure. This failure information alone can reduce failures by indicating specific problem areas. These results are expected to yield improved choice of metal bar stock, thread design, and make-up practices which can reduce sucker rod failures.

  8. Analysis of sucker rod and sinkerbar failures

    SciTech Connect

    Waggoner, J.R.; Buchheit, R.G.

    1992-01-01

    This paper presents results from a study to analyze the performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, structural finite element analysis, and detailed failure data collection. Metallography demonstrated that microstructure of steel bar stock needs to be considered. Current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding. Finite element analysis of the threaded connection identifies stress and fatigue concentrations and quantitatively assesses the performance and failure of coupling designs under a variety of loading conditions. Subcritical fractures observed in the metallography are also suggested by the calculated stress distribution in the threaded coupling. Failure data illustrates both magnitude and frequency of the failures, as well as categorizing the suspected cause of failure. This failure information alone can reduce failures by indicating specific problem areas. These results are expected to yield improved choice of metal bar stock, thread design, and make-up practices which can reduce sucker rod failures.

  9. Fluid Dynamics in Sucker Rod Pumps

    SciTech Connect

    Cutler, Robert P.; Mansure, Arthur J.

    1999-06-01

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

  10. Sucker rod coupling with protective coating

    SciTech Connect

    Gray, K.W.

    1990-03-06

    This patent describes a coupling adapted to be used in a string of oil well sucker rods. It comprises: a cylindrical metallic cuff having a radial face at each end and internal threads for its entire length, having a resinous coating about 0.040 inches thick bonded over all of the external surfaces, the resinous coating is fused onto the metal. This patent describes a second coupling adapted to be used in a string of oil well sucker rods. It comprises: a cylindrical metallic cuff having a radial face at each end and internal threads for its entire length, having a resinous coating bonded over all of the external surfaces, the resinous coating is fused onto the metal, a distal plug within one end of the cuff, the distal plug snugly fitting the threads of one end and covering all internal surfaces, and an eyelet plug on the other end. The eyelet plug extending within the other end and covering the threads of that end and all internal surfaces.

  11. Homogeneous cooling state of frictionless rod particles

    NASA Astrophysics Data System (ADS)

    Rubio-Largo, S. M.; Alonso-Marroquin, F.; Weinhart, T.; Luding, S.; Hidalgo, R. C.

    2016-02-01

    In this work, we report some theoretical results on granular gases consisting of frictionless 3D rods with low energy dissipation. We performed simulations on the temporal evolution of soft spherocylinders, using a molecular dynamics algorithm implemented on GPU architecture. A homogeneous cooling state for rods, where the time dependence of the system's intensive variables occurs only through a global granular temperature, has been identified. We have found a homogeneous cooling process, which is in excellent agreement with Haff's law, when using an adequate rescaling time τ(ξ), the value of which depends on the particle elongation ξ and the restitution coefficient. It was further found that scaled particle velocity distributions remain approximately Gaussian regardless of the particle shape. Similarly to a system of ellipsoids, energy equipartition between rotational and translational degrees of freedom was better satisfied as one gets closer to the elastic limit. Taking advantage of scaling properties, we have numerically determined the general functionality of the magnitude Dc(ξ), which describes the efficiency of the energy interchange between rotational and translational degrees of freedom, as well as its dependence on particle shape. We have detected a range of particle elongations (1.5 < ξ < 4.0), where the average energy transfer between the rotational and translational degrees of freedom results greater for spherocylinders than for homogeneous ellipsoids with the same aspect ratio.

  12. Application of polyimide actuator rod seals

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  13. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  14. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  15. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  16. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  17. Effect of Different Distal Fixation Augmentation Methods on the Pullout Strength of Fassier-Duval Telescoping Rods.

    PubMed

    Mansour, Alfred; Barsi, James; Baldini, Todd; Georgopoulos, Gaia

    2016-01-01

    Antegrade telescoping rods have been introduced for use in pediatric patients with osteogenesis imperfecta (OI) to decrease the incidence of long-bone fractures and to correct and prevent deformities. Recent studies have documented failures of telescoping intramedullary rods due to inadequate distal fixation. The purpose of this study was to evaluate the pullout strength of distal fixation of the telescoping rod with and without synthetic calcium phosphate or polymethylmethacrylate (PMMA) augmentation. Four sets of 6 telescoping distal fixation rods were fixed according to standard insertion technique into an open-cell rigid-foam synthetic bone block simulating OI bone. The groups tested were as follows: control (no augmentation), 0.75 mL of PMMA-augmented, 0.75 mL of PMMA-rescued (stripped distal fixation, then resecured after PMMA augmentation), and 0.75 mL of bioabsorbable-calcium phosphate (CP)-augmented. All rods were tested to failure. The peak load was recorded. Average pullout strengths were as follows: control, 20±6.6 N; PMMA, 125±16.8 N; PMMA-rescued, 137±11.9 N; bioabsorbable-CP, 81±10.3 N. All augmented groups had significantly higher pullout strength compared with the control (P<.001). The PMMA and PMMA-rescued groups failed at the PMMA/bone interface, whereas the bioabsorbable-CP group failed at the cement/rod interface. All augmented constructs improved pullout strength by at least 400% compared with the control. Bioabsorbable cement may be less detrimental to the physis if pullout still occurs despite augmentation due to its mode of failure. This study provides biomechanical evidence to support the further in vivo investigation of either PMMA or bioabsorbable cement augmentation to improve pullout strength of distal telescoping rod fixation.

  18. Phase diagrams of charged colloidal rods: Can a uniaxial charge distribution break chiral symmetry?

    NASA Astrophysics Data System (ADS)

    Drwenski, Tara; Dussi, Simone; Hermes, Michiel; Dijkstra, Marjolein; van Roij, René

    2016-03-01

    We construct phase diagrams for charged rodlike colloids within the second-virial approximation as a function of rod concentration, salt concentration, and colloidal charge. Besides the expected isotropic-nematic transition, we also find parameter regimes with a coexistence between a nematic and a second, more highly aligned nematic phase including an isotropic-nematic-nematic triple point and a nematic-nematic critical point, which can all be explained in terms of the twisting effect. We compute the Frank elastic constants to see if the twist elastic constant can become negative, which would indicate the possibility of a cholesteric phase spontaneously forming. Although the twisting effect reduces the twist elastic constant, we find that it always remains positive. In addition, we find that for finite aspect-ratio rods the twist elastic constant is also always positive, such that there is no evidence of chiral symmetry breaking due to a uniaxial charge distribution.

  19. Cavitation erosion mechanism of titanium alloy radiation rods in aluminum melt.

    PubMed

    Dong, Fang; Li, Xiaoqian; Zhang, Lihua; Ma, Liyong; Li, Ruiqing

    2016-07-01

    Ultrasound radiation rods play a key role in introducing ultrasonic to the grain refinement of large-size cast aluminum ingots (with diameter over 800 mm), but the severe cavitation corrosion of radiation rods limit the wide application of ultrasonic in the metallurgy field. In this paper, the cavitation erosion of Ti alloy radiation rod (TARR) in the semi-continuous direct-chill casting of 7050 Al alloy was investigated using a 20 kHz ultrasonic vibrator. The macro/micro characterization of Ti alloy was performed using an optical digital microscopy and a scanning electron microscopy, respectively. The results indicated that the cavitation erosion and the chemical reaction play different roles throughout different corrosion periods. Meanwhile, the relationship between mass-loss and time during cavitation erosion was measured and analyzed. According to the rate of mass-loss to time, the whole cavitation erosion process was divided into four individual periods and the mechanism in each period was studied accordingly. PMID:26964935

  20. Simulation of the cygnus rod-pinch diode using the radiographic chain model

    SciTech Connect

    Kwan, Thomas Jt; Wang, Tai - Sen F; Berninger, Michael; Snell, Charles M; Lin, Yin

    2008-01-01

    The Cygnus radiographic machine is a relatively compact low-energy (<3 MV) x-ray source with some extremely desirable features for radiographic applications. These features include small spot size critical for high-spatial resolution and high dose in a low energy range. The x-ray source is based on bremsstrahlung production in a small diameter ({approx}0.75 mm) tungsten rod by a high-current ({approx}60 kA) electron beam converging at the tip of the rod. For quantitative analysis of radiographic data, it is essential to determine the bremsstrahlung spectrum accurately. We have used the radiographic chain model that self-consistently models the diode with a two-dimensional particle-in-cell code (Merlin) which links to an electron-photon Monte Carlo code to obtain the spectrum under three different situations. These are: steady state spectrum using a voltage puise of 2.5 MV, time-integrated spectrum using a time-dependent experimental voltage pulse, and inclusion of reflexing electrons at the anode in our particle-in-cell simulation. Detailed electron dynamics have been obtained in our study. Our investigations conclude that the time integrated bremsstrahlung spectrum is significantly softer than that of the steady state. In our latest simulations, we have included the effects of reflexing electrons around the anode rod and found the spectrum to be in better agreement with experimental data.

  1. Cavitation erosion mechanism of titanium alloy radiation rods in aluminum melt.

    PubMed

    Dong, Fang; Li, Xiaoqian; Zhang, Lihua; Ma, Liyong; Li, Ruiqing

    2016-07-01

    Ultrasound radiation rods play a key role in introducing ultrasonic to the grain refinement of large-size cast aluminum ingots (with diameter over 800 mm), but the severe cavitation corrosion of radiation rods limit the wide application of ultrasonic in the metallurgy field. In this paper, the cavitation erosion of Ti alloy radiation rod (TARR) in the semi-continuous direct-chill casting of 7050 Al alloy was investigated using a 20 kHz ultrasonic vibrator. The macro/micro characterization of Ti alloy was performed using an optical digital microscopy and a scanning electron microscopy, respectively. The results indicated that the cavitation erosion and the chemical reaction play different roles throughout different corrosion periods. Meanwhile, the relationship between mass-loss and time during cavitation erosion was measured and analyzed. According to the rate of mass-loss to time, the whole cavitation erosion process was divided into four individual periods and the mechanism in each period was studied accordingly.

  2. Rod-signal interneurons in the rabbit retina: 2. AII amacrine cells.

    PubMed

    Vaney, D I; Gynther, I C; Young, H M

    1991-08-01

    AII amacrine cells, which are the third-order neurons in the rod pathway, can be differentially labelled in rabbit retina by injecting Nuclear Yellow into the posterior chamber. Under ultraviolet excitation, the labelled retina appears strongly metachromatic, with the AII nuclei fluorescing silvery-yellow and the nuclei of other amacrine cells fluorescing blue. Labelled AII cells were injected with Lucifer Yellow under direct microscopic control in a superfused retinal preparation, and the dye was later photoconverted to an opaque reaction product. Rabbit AII amacrines, which number about 525,000 cells, reach a maximum density of 2,500-3,000 cells/mm2 on the peak visual streak, dropping to 400-500 cells/mm2 at the superior margin. These narrow-field amacrines have a bistratified dendritic morphology, with distinctive "lobular appendages" in sublamina a of the inner plexiform layer and wider ranging "arboreal dendrites" in sublamina b. Although the lobular field area increases 10-fold from the visual streak to the far periphery, the lobular field coverage is almost uniform across the retina, averaging 1.0 in inferior retina and 0.8 in superior retina. The dendritic field area of the arboreal dendrites also increases with eccentricity from the visual streak, but there are pronounced differences between inferior and superior retina. The arboreal fields are 2 to 3 times larger than the lobular fields throughout the inferior retina but up to 15 times larger in the superior retina. The arboreal field overlap is only 1.8 at the peak visual streak, increasing slightly to about 2.4 over most of the inferior retina; the overlap increases sharply in the superior retina, however, reaching values of 10 or more in the far periphery. Both the lobular and arboreal fields of AII cells are spaced more regularly than the somata, thus covering apparent gaps in the somatic array. An analysis of the potential convergence and divergence between rod bipolar cells and AII amacrine cells in

  3. Self-assembly of cyclic rod-coil diblock copolymers.

    PubMed

    He, Linli; Chen, Zenglei; Zhang, Ruifen; Zhang, Linxi; Jiang, Zhouting

    2013-03-01

    The phase behavior of cyclic rod-coil diblock copolymer melts is investigated by the dissipative particle dynamics simulation. In order to understand the effect of chain topological architecture better, we also study the linear rod-coil system. The comparison of the calculated phase diagrams between the two rod-coil copolymers reveals that the order-disorder transition point (χN)ODT for cyclic rod-coil diblock copolymers is always higher than that of equivalent linear rod-coil diblocks. In addition, the phase diagram for cyclic system is more "symmetrical," due to the topological constraint. Moreover, there are significant differences in the self-assembled overall morphologies and the local molecular arrangements. For example, frod = 0.5, both lamellar structures are formed while rod packing is different greatly in cyclic and linear cases. The lamellae with rods arranged coplanarly into bilayers occurs in cyclic rod-coil diblocks, while the lamellar structure with rods arranged end by end into interdigitated bilayers appears in linear counterpart. In both the lamellar phases, the domain size ratio of cyclic to linear diblocks is ranged from 0.63 to 0.70. This is attributed to that the cyclic architecture with the additional junction increases the contacts between incompatible blocks and prevents the coil chains from expanding as much as the linear cases. As frod = 0.7, the hexagonally packed cylinder is observed for cyclic rod-coil diblocks, while liquid-crystalline smectic A lamellar phase is formed in linear system. As a result, the cyclization of a linear rod-coil block copolymer can induce remarkable differences in the self-assembly behavior and also diversify its physical properties and applications greatly. PMID:23485326

  4. A λ 3 mm and 1 mm line survey toward the yellow hypergiant IRC +10420⋆

    PubMed Central

    Quintana-Lacaci, G.; Agúndez, M.; Cernicharo, J.; Bujarrabal, V.; Sánchez Contreras, C.; Castro-Carrizo, A.; Alcolea, J.

    2016-01-01

    Aims Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this purpose, we obtained full line surveys at 1 and 3 mm atmospheric windows. Methods We have identified 106 molecular emission lines from 22 molecular species. Approximately half of the molecules detected are N-bearing species, in particular HCN, HNC, CN, NO, NS, PN, and N2H+. We used rotational diagrams to derive the density and rotational temperature of the different molecular species detected. We introduced an iterative method that allows us to take moderate line opacities into account. Results We have found that IRC +10420 presents high abundances of the N-bearing molecules compared with O-rich evolved stars. This result supports the presence of a N-rich chemistry, expected for massive stars. Our analysis also suggests a decrease of the 12C/13C ratio from ≳ 7 to ~ 3.7 in the last 3800 years, which can be directly related to the nitrogen enrichment observed. In addition, we found that SiO emission presents a significant intensity decrease for high-J lines when compared with older observations. Radiative transfer modeling shows that this variation can be explained by a decrease in the infrared (IR) flux of the dust. The origin of this decrease might be an expansion of the dust shell or a lower stellar temperature due to the pulsation of the star. PMID:27458319

  5. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  6. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  7. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  8. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  9. 49 CFR 236.794 - Rod, up-and-down.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  10. Selection of slim hole core rods by vibratory analysis

    SciTech Connect

    Eustes, A.W. III; Mitchell, B.J.; Stoner, M.S.

    1994-12-01

    The purpose of this research was to determine the nature of the core rod vibrations and characterize their vibratory spectrums in order that an optimal core rod size could be chosen. The research was performed for the Yucca Mountain Site Characterization Project, US Department of Energy, Office of Civilian Radioactive Waste Management, which is directing the coring of boreholes at Yucca Mountain, Nevada. This paper describes the axial, torsional, and transient buckling vibratory models developed for the selection of optimum core rod size. The axial and torsional vibratory core rod simulator (VCRS) models are coupled by way of a transient buckling wave which propagates over the length of the core rod. This paper reports the frequencies and magnitudes of the stresses in the 101 core rod now in use. In addition, four core bit vibratory forcing functions for thrust and torque wee developed. The thrust and torque frequencies and magnitudes for the bit forcing functions were extracted from full-size laboratory core bit tests with fast Fourier transforms. The natural frequencies of the core rod were determined with closed-form solution models and were confirmed with a finite element model. Finally, a selection of core rod sizes were modeled to determine the best size to minimize damaging stress which stems from vibration.

  11. Speeding rod recovery improves temporal resolution in the retina

    PubMed Central

    Fortenbach, Christopher R.; Kessler, Christopher; Peinado, Gabriel; Burns, Marie E.

    2015-01-01

    The temporal resolution of the visual system progressively increases with light intensity. Under scotopic conditions, temporal resolution is relatively poor, and may be limited by both retinal and cortical processes. Rod photoresponses themselves are quite slow because of the slowly deactivating biochemical cascade needed for light transduction. Here, we have used a transgenic mouse line with faster than normal rod phototransduction deactivation (RGS9-overexpressors) to test whether rod signaling to second-order retinal neurons is rate-limited by phototransduction or by other mechanisms. We compared electrical responses of individual wild-type and RGS9-overexpressing (RGS9-ox) rods to steady illumination and found that RGS9-ox rods required 2-fold brighter light for comparable activation, owing to faster G-protein deactivation. When presented with flickering stimuli, RGS9-ox rods showed greater magnitude fluctuations around a given steady-state current amplitude. Likewise, in vivo electroretinography (ERG) and whole-cell recording from OFF-bipolar, rod bipolar, and horizontal cells of RGS9-ox mice displayed larger than normal magnitude flicker responses, demonstrating an improved ability to transmit frequency information across the rod synapse. Slow phototransduction recovery therefore limits synaptic transmission of increments and decrements of light intensity across the first retinal synapse in normal retinas, apparently sacrificing temporal responsiveness for greater overall sensitivity in ambient light. PMID:25748270

  12. Designing a sucker-rod pumping system for maximum efficiency

    SciTech Connect

    Gault, R.H.

    1987-11-01

    Consideration of the energy requirements in the design of a sucker-rod pumping system is very important. Examples are given that detail how the use of the largest possible pump with the lightest, strongest rod string and special-geometry units can provide a substantial energy reduction.

  13. Designing a sucker rod pumping system for maximum efficiency

    SciTech Connect

    Gault, R.H.

    1985-01-01

    Consideration of the energy requirements in the design of a sucker rod pumping system is very important. Examples are given which detail how the use of the largest possible pump with the lightest, strongest, rod string and special geometry units can provide a substantial energy reduction.

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

    DOEpatents

    Hausner, H.H.

    1958-12-30

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

  15. Packed rod neutron shield for fast nuclear reactors

    DOEpatents

    Eck, John E.; Kasberg, Alvin H.

    1978-01-01

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

  16. Dynamics of gas-fluidized granular rods

    NASA Astrophysics Data System (ADS)

    Daniels, L. J.; Park, Y.; Lubensky, T. C.; Durian, D. J.

    2009-04-01

    We study a quasi-two-dimensional monolayer of granular rods fluidized by a spatially and temporally homogeneous upflow of air. By tracking the position and orientation of the particles, we characterize the dynamics of the system with sufficient resolution to observe ballistic motion at the shortest time scales. Particle anisotropy gives rise to dynamical anisotropy and superdiffusive dynamics parallel to the rod’s long axis, causing the parallel and perpendicular mean-square displacements to become diffusive on different time scales. The distributions of free times and free paths between collisions deviate from exponential behavior, underscoring the nonthermal character of the particle motion. The dynamics show evidence of rotational-translational coupling similar to that of an anisotropic Brownian particle. We model rotational-translational coupling in the single-particle dynamics with a modified Langevin model using nonthermal noise sources. This suggests a phenomenological approach to thinking about collections of self-propelling particles in terms of enhanced memory effects.

  17. 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.

  18. RodZ and PgsA Play Intertwined Roles in Membrane Homeostasis of Bacillus subtilis and Resistance to Weak Organic Acid Stress

    PubMed Central

    van Beilen, Johan; Blohmke, Christoph J.; Folkerts, Hendrik; de Boer, Richard; Zakrzewska, Anna; Kulik, Wim; Vaz, Fred M.; Brul, Stanley; Ter Beek, Alexander

    2016-01-01

    Weak organic acids like sorbic and acetic acid are widely used to prevent growth of spoilage organisms such as Bacilli. To identify genes involved in weak acid stress tolerance we screened a transposon mutant library of Bacillus subtilis for sorbic acid sensitivity. Mutants of the rodZ (ymfM) gene were found to be hypersensitive to the lipophilic weak organic acid. RodZ is involved in determining the cell’s rod-shape and believed to interact with the bacterial actin-like MreB cytoskeleton. Since rodZ lies upstream in the genome of the essential gene pgsA (phosphatidylglycerol phosphate synthase) we hypothesized that expression of the latter might also be affected in rodZ mutants and hence contribute to the phenotype observed. We show that both genes are co-transcribed and that both the rodZ::mini-Tn10 mutant and a conditional pgsA mutant, under conditions of minimal pgsA expression, were sensitive to sorbic and acetic acid. Both strains displayed a severely altered membrane composition. Compared to the wild-type strain, phosphatidylglycerol and cardiolipin levels were lowered and the average acyl chain length was elongated. Induction of rodZ expression from a plasmid in our transposon mutant led to no recovery of weak acid susceptibility comparable to wild-type levels. However, pgsA overexpression in the same mutant partly restored sorbic acid susceptibility and fully restored acetic acid sensitivity. A construct containing both rodZ and pgsA as on the genome led to some restored growth as well. We propose that RodZ and PgsA play intertwined roles in membrane homeostasis and tolerance to weak organic acid stress.

  19. Protective effect of taurine on the light-induced disruption of isolated frog rod outer segments

    SciTech Connect

    Pasantes-Morales, H.; Ademe, R.M.; Quesada, O.

    1981-01-01

    Isolated frog rod outer segments (ROS) incubated in a Krebs-bicarbonate medium, and illuminated for 2 h, show a profound alteration in their structure. This is characterized by distention of discs, vesiculation, and a marked swelling. The light-induced ROS disruption requires the presence of bicarbonate and sodium chloride. Replacement of bicarbonate by TRIS or HEPES protects ROS structure. Also, substitution of sodium chloride by sucrose or choline chloride maintains unaltered the ROS structure. Deletion of calcium, magnesium, or phosphate does not modify the effect produced by illumination. An increased accumulation of labeled bicarbonate and tritiated water is observed in illuminated ROS, as compared with controls in the dark. The presence of taurine, GABA, or glycine, at concentrations of 5-25 mM, effectively counteracts the light-induced ROS disruption. Taurine (25 mM) reduces labeled bicarbonate and tritiated water levels to those observed in the dark incubated ROS.

  20. Luminescent molecular rods - transition-metal alkynyl complexes.

    PubMed

    Yam, Vivian Wing-Wah; Wong, Keith Man-Chung

    2005-01-01

    A number of transition-metal complexes have been reported to exhibit rich luminescence, usually originating from phosphorescence. Such luminescence properties of the triplet excited state with a large Stoke's shift, long lifetime, high luminescence quantum yield as well as lower excitation energy, are envisaged to serve as an ideal candidate in the area of potential applications for chemosensors, dye-sensitized solar cells, flat panel displays, optics, new materials and biological sciences. Organic alkynes (poly-ynes), with extended or conjugatedπ-systems and rigid structure with linear geometry, have become a significant research area due to their novel electronic and physical properties and their potential applications in nanotechnology. Owing to the presence of unsaturated sp-hybridized carbon atoms, the alkynyl unit can serve as a versatile building block in the construction of alkynyl transition-metal complexes, not only throughσ-bonding but also viaπ-bonding interactions. By incorporation of linear alkynyl groups into luminescent transition-metal complexes, the alkynyl moiety with goodσ-donor,π-donor andπ-acceptor abilities is envisaged to tune or perturb the emission behaviors, including emission energy (color), intensity and lifetime by its role as an auxiliary ligand as well as to govern the emission origin from its direct involvement. This review summarizes recent efforts on the synthesis of luminescent rod-like alkynyl complexes with different classes of transition metals and details the effects of the introduction of alkynyl groups on the luminescence properties of the complexes. PMID:22179333

  1. Luminescent molecular rods - transition-metal alkynyl complexes.

    PubMed

    Yam, Vivian Wing-Wah; Wong, Keith Man-Chung

    2005-01-01

    A number of transition-metal complexes have been reported to exhibit rich luminescence, usually originating from phosphorescence. Such luminescence properties of the triplet excited state with a large Stoke's shift, long lifetime, high luminescence quantum yield as well as lower excitation energy, are envisaged to serve as an ideal candidate in the area of potential applications for chemosensors, dye-sensitized solar cells, flat panel displays, optics, new materials and biological sciences. Organic alkynes (poly-ynes), with extended or conjugatedπ-systems and rigid structure with linear geometry, have become a significant research area due to their novel electronic and physical properties and their potential applications in nanotechnology. Owing to the presence of unsaturated sp-hybridized carbon atoms, the alkynyl unit can serve as a versatile building block in the construction of alkynyl transition-metal complexes, not only throughσ-bonding but also viaπ-bonding interactions. By incorporation of linear alkynyl groups into luminescent transition-metal complexes, the alkynyl moiety with goodσ-donor,π-donor andπ-acceptor abilities is envisaged to tune or perturb the emission behaviors, including emission energy (color), intensity and lifetime by its role as an auxiliary ligand as well as to govern the emission origin from its direct involvement. This review summarizes recent efforts on the synthesis of luminescent rod-like alkynyl complexes with different classes of transition metals and details the effects of the introduction of alkynyl groups on the luminescence properties of the complexes.

  2. Semiconductor Quantum Rods as Single Molecule FluorescentBiological Labels

    SciTech Connect

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

    2006-05-29

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

  3. 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%.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Chatterjee, Avik P.; Grimaldi, Claudio

    2015-09-01

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

  6. Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod.

    PubMed

    Schwing, Patrick T; Romero, Isabel C; Larson, Rebekka A; O'Malley, Bryan J; Fridrik, Erika E; Goddard, Ethan A; Brooks, Gregg R; Hastings, David W; Rosenheim, Brad E; Hollander, David J; Grant, Guy; Mulhollan, Jim

    2016-01-01

    Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments.

  7. Receptive field properties of rod-driven horizontal cells in the skate retina.

    PubMed

    Qian, H; Ripps, H

    1992-09-01

    The large receptive fields of retinal horizontal cells result primarily from extensive intercellular coupling via gap (electrical) junctions; thus, the extent of the receptive field provides an index of the degree to which the cells are electrically coupled. For rod-driven horizontal cells in the dark-adapted skate retina, a space constant of 1.18 +/- 0.15 mm (SD) was obtained from measurements with a moving slit stimulus, and a comparable value (1.43 +/- 0.55 mm) was obtained with variation in spot diameter. These values, and the extensive spread of a fluorescent dye (Lucifer Yellow) from the site of injection to neighboring cells, indicate that the horizontal cells of the all-rod retina of skate are well coupled electrically. Neither the receptive field properties nor the gap-junctional features of skate horizontal cells were influenced by the adaptive state of the retina: (a) the receptive field organization was unaffected by light adaptation, (b) similar dye coupling was seen in both dark- and light-adapted retinae, and (c) no significant differences were found in the gap-junctional particle densities measured in dark- and light-adapted retinas, i.e., 3,184 +/- 286/microns 2 (n = 8) and 3,073 +/- 494/microns 2 (n = 11), respectively. Moreover, the receptive fields of skate horizontal cells were not altered by either dopamine, glycine, GABA, or the GABAA receptor antagonists bicuculline and picrotoxin. We conclude that the rod-driven horizontal cells of the skate retina are tightly coupled to one another, and that the coupling is not affected by photic and pharmacological conditions that are known to modulate intercellular coupling between cone-driven horizontal cells in other species. PMID:1359000

  8. Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod.

    PubMed

    Schwing, Patrick T; Romero, Isabel C; Larson, Rebekka A; O'Malley, Bryan J; Fridrik, Erika E; Goddard, Ethan A; Brooks, Gregg R; Hastings, David W; Rosenheim, Brad E; Hollander, David J; Grant, Guy; Mulhollan, Jim

    2016-01-01

    Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments. PMID:27585268

  9. Age-Related Deterioration of Rod Vision in Mice

    PubMed Central

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

    2010-01-01

    Even in healthy individuals, aging leads to deterioration in visual acuity, contrast sensitivity, visual field, and dark adaptation. Little is known about the neural mechanisms that drive the age-related changes of the retina and more specifically of photoreceptors. According to one hypothesis, the age-related deterioration in rod function is due to the limited availability of 11-cis-retinal for rod pigment formation. To determine how aging affects rod photoreceptors and to test the retinoid deficiency hypothesis, we compared the morphological and functional properties of rods of adult and aged B6D2F1/J mice. We found that the number of rods and the length of their outer segments were significantly reduced in 2.5 year-old mice compared to 4 month-old animals. Aging also resulted in a 2-fold reduction in the total level of opsin in the retina. Behavioral tests revealed that scotopic visual acuity and contrast sensitivity were decreased by 2-fold in aged mice, and rod ERG recordings demonstrated reduced amplitudes of both a- and b-waves. Sensitivity of aged rods determined from single-cell recordings was also decreased by 1.5-fold, corresponding to not more than 1% free opsin in these photoreceptors, and kinetic parameters of dim flash response were not altered. Notably, the rate of rod dark adaptation was unaffected by age. Thus, our results argue against age-related deficiency of 11-cis-retinal in the B6D2F1/J mouse rod visual cycle. Surprisingly, the level of cellular dark noise was increased in aged rods providing an alternative mechanism for their desensitization. PMID:20720130

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

    SciTech Connect

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

    2012-06-06

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  12. Deep rolling of titanium rods for application in modular total hip arthroplasty.

    PubMed

    Schuh, Alexander; Zeller, Christian; Holzwarth, Ulrich; Kachler, Werner; Wilcke, Gerhard; Zeiler, Günther; Eigenmann, Bernd; Bigoney, Jean

    2007-05-01

    Compressive residual stresses are commonly introduced into the near-surface regions of morse taper junctions of modular hip endoprostheses to prolong fatigue life. An increasing number of publications report that contamination of shot-peened surfaces can lead to enhanced corrosion and third body wear. This study evaluates deep rolling of titanium alloy rods as a possible alternative to shot peening. Ten rods of Ti6Al7Nb alloy with a diameter of 15 mm were deep rolled with various rolling parameters. The resulting surface topography and residual contamination was analyzed using a scanning electron microscope (SEM). The near-surface residual stress states after deep rolling were characterized by means of X-ray diffraction. The roughness of the surfaces before deep rolling was about R(z) = 14 microm, and after deep rolling surface roughness values of R(z) 0.4-7.5 microm were achieved. The results of the SEM and EDAX analyses of the sample surface showed no evidence of surface contamination by particles or abrasion products caused by any process. At a pressure of 300 bar, compressive stress reached the maximum of -1150 MPa at a depth of 0.1 mm. Deep rolling thus allows a smooth and particle-free surface to be obtained and therefore shows promise as a surface treatment for mating surfaces of morse tapers in modular hip endoprostheses.

  13. Index to 8mm Motion Cartridges. Third Edition.

    ERIC Educational Resources Information Center

    University of Southern California, Los Angeles. National Information Center for Educational Media.

    Research at the National Information Center for Educational Media has shown that the 8mm motion cartridge with optical and magnetic sound seems to meet the basic tenets of a prime educational criterion for an educational medium--that it be available to the learner at his convenience. This is a bibliographical source for 8mm motion cartridges, and…

  14. Index to 8mm Motion Cartridges. Fourth Edition.

    ERIC Educational Resources Information Center

    University of Southern California, Los Angeles. National Information Center for Educational Media.

    Research at the National Information Center for Educational Media (NICEM) has shown that the 8mm motion cartridge with optical and magnetic sound seems to meet the basic tenets of a prime educational criterion for an educational medium--that it be available to the learner at his convenience. This is a bibliographical source for 8mm motion…

  15. Do Noncontingent Interviewer Mm-hmms Facilitate Interviewee Productivity?

    ERIC Educational Resources Information Center

    Siegman, Aron Wolfe

    1976-01-01

    Two studies investigated the hypothesis that noncontingent interviewer "mm-hmms" facilitate interviewee verbal productivity. Within- and between-subjects comparisons failed to support the hypothesis, although interviewees' ratings indicate that the mm-hmms were perceived as the social reinforcers they were intended to be. (Author)

  16. Is smaller better? Comparison of 3-mm and 5-mm leaf size for stereotactic radiosurgery: A dosimetric study

    SciTech Connect

    Chern, Shyh-shi . E-mail: Richard.Chern@hci.utah.edu; Leavitt, Dennis D.; Jensen, Randy L.; Shrieve, Dennis C.

    2006-11-15

    Purpose: To perform a dosimetric comparison of a minimal 3-mm leaf width multileaf collimator (MLC) and a minimal 5-mm MLC in dynamic conformal arc stereotactic radiosurgery for treatment of intracranial lesions. Methods and Materials: The treatment plans of 23 patients previously treated for intracranial lesions in our institution were redone using the BrainSCAN, version 5.3, stereotactic radiosurgery treatment planning system (BrainLAB). For each case, two dynamic conformal arc plans were generated: one using a minimal 3-mm micro-MLC (BrainLAB, Novalis) and one using a minimal 5-mm MLC (Varian Millennium). All arc parameters were the same in each of the two plans, except for the collimator angle settings. The collimator angle settings were optimized for each arc in each plan. A peritumoral rind structure (1 cm) was created to evaluate normal tissue sparing immediately adjacent to the target volume. Conformity indexes (CIs) were calculated for each plan. The dependence of normal tissue sparing and target conformity on target volume (TV) was determined. Results: The TV was 0.14-36.32 cm{sup 3} (median, 5.90). The CI was 1.22-2.60 (median, 1.51) for the 3-mm micro-MLC and 1.23-2.69 (median, 1.60) for the 5-mm MLC. Despite this small difference, it was a statistically significant increase (p < 0.0001) for the 5-mm MLC compared with the 3-mm micro-MLC. Improved normal tissue sparing was demonstrated using the 3-mm micro-MLC compared with the 5-mm MLC by examining the peritumoral rind volumes (PRVs) receiving 50% (PRV{sub 5}), 80% (PRV{sub 8}), and 90% (PRV{sub 9}) of the prescription dose. The reduction in the PRV{sub 5}, PRV{sub 8}, and PRV{sub 9} for the 3-mm micro-MLC compared with the 5-mm MLC was 13.5%, 12.9%, and 11.5%, respectively. The CI decreased with a larger TV, as did the difference in the CIs between the 3-mm micro-MLC and 5-mm MLC. A reduction in the PRV increased with larger TVs. Conclusion: The 3-mm micro-MLC provided better target conformity and

  17. A study of the methods for preventing rod-wear tubing leaks in sucker-rod pumping wells

    SciTech Connect

    McCaslin, K.P. )

    1988-11-01

    Because of the high cost associated with tubing replacement, rod-wear tubing leaks are one of the most costly types of subsurface failures on sucker-rod-pumped wells. While severe hole deviation is most often blamed for rod-wear tubing leaks, case studies show that most rod-wear leaks are caused by accelerated corrosion, which is the result of the removal of a protective corrosion scale from the inside of the tubing. For this reason, the key to eliminating rod-wear tubing leaks economically is correctly identifying the problem as either mechanical wear or corrosion wear and then implementing the appropriate corrective measures. Four case histories involving a total of 90 problem wells are presented to illustrate the methods used to differentiate between corrosion wear and mechanical wear. In these fields, tubing leaks were reduced by as much as 80% by proper identification of the cause of the leaks.

  18. Simulation study on the structure of rod-coil-rod triblock copolymer and nanoparticle mixture within slit.

    PubMed

    Huang, Jian-Hua; Fan, Zhong-Xiang; Luo, Meng-Bo

    2013-11-28

    Self-assembly structures of rod-coil-rod ABA triblock copolymer and nanoparticle mixture within a slit are simulated by dissipative particle dynamics method. Results show that the structures are dependent on the rigidity of the rod block kθ, the interaction between the rod block and slit a(wA), the fraction of rod block f(A), and the slit height H. With an increase in kθ, we observe a transition from parallel lamellae to hexagonal cylinders. While with the increase in a(wA), the parallel lamellae at small kθ and hexagonal cylinders at large kθ change to perpendicular lamellae at large a(wA) close to a(As). At last, we present a phase diagram of structure with respect to f(A) and H at large kθ. PMID:24289376

  19. mm-wave radar - The new ECM-ECCM frontier

    NASA Astrophysics Data System (ADS)

    Johnston, S. L.

    1984-05-01

    The present investigation is concerned with the relationship of mm-wave radar to electronic countermeasures (ECM)/electronic counter-countermeasures (ECCM). Electronic warfare support measures (ESM) are also considered, since employment of ECM against mm-wave radar places strong demands on ESM. The mm-waves are defined as wavelengths in the range from 1 to 10 mm corresponding to frequencies in the range from 300 to 30 GHz. Advantages of mm-waves over microwaves for radar applications are partly related to requirements for smaller antenna diameters, increased angular resolution/antenna diameter, increased bandwidth availability, increased range resolution, reduced vulnerability to unwanted detection by hostile forces, and smaller and lighter RF components.

  20. Trabecular Plates and Rods Determine Elastic Modulus and Yield Strength of Human Trabecular Bone

    PubMed Central

    Wang, Ji; Zhou, Bin; Liu, X. Sherry; Fields, Aaron J.; Sanyal, Arnav; Shi, Xiutao; Adams, Mark; Keaveny, Tony M.; Guo, X. Edward

    2014-01-01

    The microstructure of trabecular bone is usually perceived as a collection of plate-like and rod-like trabeculae, which can be determined from the emerging high-resolution skeletal imaging modalities such as micro computed tomography (μCT) or clinical high-resolution peripheral quantitative CT (HR-pQCT) using the individual trabecula segmentation (ITS) technique. It has been shown that the ITS-based plate and rod parameters are highly correlated with elastic modulus and yield strength of human trabecular bone. In the current study, plate-rod (PR) finite element (FE) models were constructed completely based on ITS-identified individual trabecular plates and rods. We hypothesized that PR FE can accurately and efficiently predict elastic modulus and yield strength of human trabecular bone. Human trabecular bone cores from proximal tibia (PT), femoral neck (FN) and greater trochanter (GT) were scanned by micro computed tomography (μCT). Specimen-specific ITS-based PR FE models were generated for each μCT image and corresponding voxel-based FE models were also generated in comparison. Both types of specimen-specific models were subjected to nonlinear FE analysis to predict the apparent elastic modulus and yield strength using the same trabecular bone tissue properties. Then, mechanical tests were performed to experimentally measure the apparent modulus and yield strength. Strong linear correlations for both elastic modulus (r2=0.97) and yield strength (r2=0.96) were found between the PR FE model predictions and experimental measures, suggesting that trabecular plates and rods morphology adequately captures three-dimensional (3D) microarchitecture of human trabecular bone. In addition, the PR FE model predictions in both elastic modulus and yield strength were highly correlated with the voxel-based FE models (r2=0.99, r2=0.98, respectively), resulted from the original 3D images without the PR segmentation. In conclusion, the ITS-based PR models predicted accurately

  1. 37. MISSISSIPPI, LOWNDES CO. COLUMBUS BRIDGE, CONSTRUCTION End of Main ...

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

    37. MISSISSIPPI, LOWNDES CO. COLUMBUS BRIDGE, CONSTRUCTION End of Main St., Columbus Overhead view of round, swing pier, showing steel reinforcing rods, workmen. During construction, 1925-27. Credit: Shenks Photography, Columbus, Ms, owner. O. Pruitt, photographer, ca. 1926. Sarcone Photography, Columbus, Ms. Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

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

    SciTech Connect

    John D. Bess; Leland M. Montierth

    2014-06-01

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

  3. Apparatus for inspecting the quality of nuclear fuel rod ends

    SciTech Connect

    Brashier, R.W.; Pfau, E.D.

    1990-09-18

    This patent describes an apparatus for inspecting the quality of both ends of nuclear fuel rods. It comprises: a housing including a pair of longitudinally separated slots for receiving X-ray downwardly therethrough from an external source and so as to define first and second longitudinally spaced apart operating positions, means for serially guiding nuclear fuel rods longitudinally through the housing and to a first rod position wherein the forward ends of the rods are aligned below the first operating position and to a second rod position wherein the rear ends of the rods are aligned below the second operating position, belt conveyor assembly means for serially advancing X-ray film cartridges longitudinally through the housing and below the rods, and so that each cartridge may be selectively aligned below the first and second operating positions; and table means supported by the conveyor frame for selectively lifting the film cartridges supported by the belts and so that the conveyor belts may be advanced while the film cartridges are held stationary.

  4. Amplitude modulation drive to rectangular-plate linear ultrasonic motors with vibrators dimensions 8 mm x 2.16 mm X 1 mm.

    PubMed

    Ming, Yang; Hanson, Ben; Levesley, Martin C; Walker, Peter G; Watterson, Kevin G

    2006-12-01

    In this paper, to exploit the contribution from not only the stators but also from other parts of miniature ultrasonic motors, an amplitude modulation drive is proposed to drive a miniature linear ultrasonic motor consisting of two rectangular piezoelectric ceramic plates. Using finite-element software, the first longitudinal and second lateral-bending frequencies of the vibrator are shown to be very close when its dimensions are 8 mm x 2.16 mm x 1 mm. So one single frequency power should be able to drive the motor. However, in practice the motor is found to be hard to move with a single frequency power because of its small vibration amplitudes and big frequency difference between its longitudinal and bending resonance, which is induced by the boundary condition variation. To drive the motor effectively, an amplitude modulation drive is used by superimposing two signals with nearly the same frequencies, around the resonant frequency of the vibrators of the linear motor. When the amplitude modulation frequency is close to the resonant frequency of the vibrator's surroundings, experimental results show that the linear motor can move back and forward with a maximum thrust force (over 0.016 N) and a maximum velocity (over 50 mm/s).

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

    SciTech Connect

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

    1981-02-01

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

  6. Japanese Science Films; a Descriptive and Evaluative Catalog of: 16mm Motion Pictures, 8mm Cartridges, and Video Tapes.

    ERIC Educational Resources Information Center

    Newren, Edward F., Ed.

    One hundred and eighty Japanese 16mm motion pictures, 8mm cartridges, and video tapes produced and judged appropriate for a variety of audience levels are listed in alphabetical order by title with descriptive and evaluative information. A subject heading list and a subject index to the film titles are included, as well as a sample of the…

  7. Anisotropy in CdSe quantum rods

    SciTech Connect

    Li, Liang-shi

    2003-09-01

    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

  8. Intracellular recordings of rod responses during dark-adaptation.

    PubMed Central

    Grabowski, S R; Pak, W L

    1975-01-01

    1. Dark-adaptation of rod photoreceptors has been studied in the isolated axolotl (Ambystoma mexicanum) retina by intracellular recordings. Rod responsiveness was greatly reduced immediately after a 30 sec partial bleach, but partially recovered with time in the dark. 2. In parallel spectrophotometric measurements using isolated retinas, regeneration of the rod pigment could not be detected after a 30 sec bleach. 3. During rod dark-adaptation, the response of a rod to a given stimulus increased in amplitude, duration, and rate of rise but did not recover completely to the dark-adapted values. Response latency was lengthened immediately after a bleach but ultimately returned to the dark-adapted level. 4. The time courses of dark-adaptation determined on the basis of the intensity of a stimulus needed to evoke a response having a criterion amplitude, a criterion duration, or a criterion rate of rise were similar. On the other hand changes in latency of the response and magnitude of the saturated amplitude followed different time courses. Change in log threshold was found to be related to change in saturated amplitude by an exponential function during dark-adaptation. 5. After bleaching 10% or less of the rod pigment, the kinetics of both recovery of log threshold and decrease in absorbance at 400 nm (metarhodopsin II+free retinal) could be described by two concurrent first-order processes having similar time constants. However, after bleaching more than 10% of the rod pigment, changes in sensitivity and absorbance did not follow parallel time courses. 6. Metarhodopsin III cannot be solely responsible for setting the axolotl rod sensitivity since rod thresholds decrease monotonically during dark-adaptation whereas meta III concentration reaches a peak 3 min after the bleach and decreases thereafter. PMID:1151778

  9. 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.

  10. 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.

  11. Deep sucker rod pumping for gas well unloading

    SciTech Connect

    Henderson, L.J.

    1984-09-01

    Exxon Company, U.S.A.'s Pyote Gas Unit 14-1 in the Block 16 (Ellenburger) field became the world's deepest rod pumped well on October 7, 1983. The rod pump was installed at 16,850 ft. in an attempt to extend the productive life of the well. The artificial lift system was designed to lift wellbore fluid that was restricting the flow of gas, thus allowing the gas to be produced up the tubing-casing annulus. Implementation of the project was possible because of the recent improvements in predictive techniques, materials available for rod pumping, and industry's experience in artificial lift.

  12. 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

  13. Connecting rod for internal combustion engine and method of manufacture

    SciTech Connect

    Machida, I.; Sato, Y.; Yamada, Y.

    1989-05-09

    A connecting rod is described for an internal combustion engine having a crankshaft axis and a piston axis the connecting rod comprising: a pair of flanges disposed in parallel relation with a plane including the crankshaft axis and the piston pin axis, each flange having a body and edges, each edge having a lateral rounded projection thereon, such that the edges are thicker than the body; and a web connecting the pair of flanges together, the web and flanges thereby forming a rod portion having a generally I-shaped section.

  14. In vivo imaging of the human rod photoreceptor mosaic

    PubMed Central

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

    2011-01-01

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

  15. 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.

  16. End-of-life nondestructive examination of Light Water Breeder Reactor fuel rods (LWBR Development Program)

    SciTech Connect

    Gorscak, D.A.; Campbell, W.R.; Clayton, J.C.

    1987-10-01

    In-bundle and out-of-bundle (single rod) nondestructive examinations of Light Water Breeder Reactor fuel rods were performed. In-bundle examinations included visual examination and measurement of rod bow, rod-to-rod gaps, and rod removal forces. Out-of-bundle examinations included rod visuals and measurement of fuel rod length, diameter and ovality, cladding oxide and crud thickness, support grid induced cladding wear mark depth and volume, and fuel rod free hanging bow. The out-of-bundle examination also included ultrasonic inspection for cladding defects, neutron radiography for pellet integrity and plenum gap measurements, and gamma scans for instack axial gap screening and binary fuel stack length measurements. The measurements confirmed design predictions of fuel rod performance and provided evidence of excellent fuel rod performance for operation of Light Water Breeder Reactor to 29,047 effective full power hours (EFPH).

  17. Guide for well pump sucker rod

    SciTech Connect

    Wilson, J.A.; Heinonen, R.L.

    1986-12-30

    This patent describes a well pump sucker rod guide comprising: a substantially cylindrical elastic body having a longitudinal bore along an axis conincident with the longitudinal axis of the body; the body having a transverse mounting slot extending from a side of the body into the body intersecting the bore and dividing the body into opposite end portions; the body having two longitudinal mounting slots; each of the end portions of the body having one of the longitudinal mounting slots opening through a side of the body into the longitudinal bore and opening at one end into the transverse mounting slot and at the other end thereof through the adjacent end of the body; the longitudinal mounting slots being aligned radially in the same directions as the transverse slot; one of the longitudinal mounting slots opening through one side of the body and the other of the longitudinal mounting slots opening through the opposite side of the body; each of the mounting slots being defined by side guide surface walls sloping radially in converging relation toward the longitudinal bore and sloping longitudinally in converging relation away from the transverse mounting slot and toward the end of the body through which each of the respective longitudinal mounting slots open.

  18. Rod gripper, changer, and storage system

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  19. Quantum rods as nanocarriers of gene therapy.

    PubMed

    Aalinkeel, Ravikumar; Nair, Bindukumar; Reynolds, Jessica L; Sykes, Donald E; Law, Wing-Cheung; Mahajan, Supriya D; Prasad, Paras N; Schwartz, Stanley A

    2012-05-01

    Both antisense oligonucleotides (ASODN) and small interfering RNA (siRNA) have enormous potential to selectively silence specific cancer-related genes and could therefore be developed to be important therapeutic anti-cancer drugs. The use of nanotechnology may allow for significant advancement of the therapeutic potential of ASODN and siRNA, due to improved pharmacokinetics, bio-distribution and tissue specific targeted therapy. In this mini-review, we have discussed the advantages of using a nanocarrier such as a multimodal quantum rod (QR) complexed with siRNA for gene delivery. Comparisons are made between ASODN and siRNA therapeutic efficacies in the context of cancer and the enormous application potential of nanotechnology in oncotherapy is discussed. We have shown that a QR-interleukin-8 (IL-8) siRNA nanoplex can effectively silence IL-8 gene expression in the PC-3 prostate cancer cells with no significant toxicity. Thus, nanocarriers such as QRs can help translate the potent effects of ASODN/siRNA into a clinically viable anti-cancer therapy. Drug delivery for cancer therapy, with the aid of nanotechnology is one of the major translational aspects of nanomedicine, and efficient delivery of chemotherapy drugs and gene therapy drugs or their co-delivery continue to be a major focus of nanomedicine research.

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

    SciTech Connect

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

    2015-04-28

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

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

    DOE PAGES

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

    2016-06-29

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  3. Building 1204, oblique view to east, 90 mm lens. ...

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

    Building 1204, oblique view to east, 90 mm lens. - Travis Air Force Base, Squadron Operations & Readiness Crew Facility, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  4. Building 1204, oblique view to west, 135 mm lens. ...

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

    Building 1204, oblique view to west, 135 mm lens. - Travis Air Force Base, Squadron Operations & Readiness Crew Facility, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  5. Building 909, oblique view to southeast, 135 mm lens. Building ...

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

    Building 909, oblique view to southeast, 135 mm lens. Building 908 at extreme right for context. - Travis Air Force Base, Handling Crew Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  6. Building 931, oblique view to southeast, 135 mm lens. ...

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

    Building 931, oblique view to southeast, 135 mm lens. - Travis Air Force Base, Central Battery Charging Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  7. Building 904, oblique view to northwest, 135 mm lens ...

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

    Building 904, oblique view to northwest, 135 mm lens - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  8. Building 931, oblique view to northwest, 210 mm lens. ...

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

    Building 931, oblique view to northwest, 210 mm lens. - Travis Air Force Base, Central Battery Charging Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  9. Building 904, oblique view to southeast, 135 mm lens. ...

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

    Building 904, oblique view to southeast, 135 mm lens. - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  10. Building 904, oblique view to northeast, 210mm lens Travis ...

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

    Building 904, oblique view to northeast, 210mm lens - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  11. Building 932, oblique view to northwest, 90 mm lens. Building ...

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

    Building 932, oblique view to northwest, 90 mm lens. Building 933-935 at extreme left. - Travis Air Force Base, Nuclear Weapons Assembly Plant 5, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  12. Electromagnetic launch of mm-size pellets to great velocities

    SciTech Connect

    Drobyshevski, E.M.; Zhukov, B.G.; Kurakin, R.O.; Sakharov, V.A.; Studenkov, A.M.

    1994-11-01

    Small body launching that uses gas or plasma faces the fundamental problem caused by excess energy loss that is due to the great wall surface/volume ratio of the barrel. For example, the efficiency of the plasma armature (PA) rail-gun acceleration is maximum for 8-10 mm-size bodies and drops as their size decreases. That is why in the case of nuclear fusion applications, where 1-2 mm-size pellets at 5-10 km/s velocity are desirable, electromagnetic launchers have not yet demonstrated an advantage over light-gas guns and one is now forced to search for a compromise between the pellet size (increasing it up to 3-4 mm) and its velocity (decreasing it down to {approx}3 km/s). As a whole, the probability of attaining 5-10 km/s velocity for 1-2 mm pellets seems to be rather remote at the present.

  13. Purification and properties of the light-activated cyclic nucleotide phosphodiesterase of rod outer segments.

    PubMed

    Miki, N; Baraban, J M; Keirns, J J; Boyce, J J; Bitensky, M W

    1975-08-25

    Frog (Rana catesbiana) rod outer segment disc membranes contain a cyclic nucleotide phosphodiesterase (EC 3.1.4.17) which is activated by light in the presence of ATP. This enzyme is firmly bound to the disc membrane, but can be eluted from the membrane with 10 mM Tris-HCl buffer, pH 7.4 and 2 mM EDTA. The eluted phosphodiesterase has reduced activity, but can be activated approximately 10-fold by polycations such as protamine and polylysine. The eluted phosphodiesterase can no longer be activated by light in the presence of ATP, that is, activation by light apparently depends on the native orientation of phosphodiesterase in relationship to other disc membrane components. The eluted phosphodiesterase was purified to homogeneity as judged by analytical polyacrylamide gel electrophoresis and polyacrylamide gel isoelectric focusing. The over-all purification from intact retina was approximately 925-fold. The purification of phosphodiesterase from the isolated rod outer segment preparation was about 185-fold with a 28% yield. Phosphodiesterase accounts for approximately 0.5% of the disc membrane protein. The eluted phosphodiesterase (inactive form) has a sedimentation coefficient of 12.4 S corresponding to an approximate molecular weight of 240,000. Sodium dodecyl sulfate polyacrylamide gel electrophoresis separates the purified phosphodiesterase into two subunits of 120,000 and 110,000 daltons. With cyclic 3':5'-GMP (cGMP) as substrate the Km for the purified phosphodiesterase is 70 muM. Protamine increases the Vmax without changing the Km for cGMP. The isoelectric point (pI) of the native dimer is 5.7. Limited exposure of the eluted phosphodiesterase (inactive form) to trypsin produces a somewhat greater activation than is obtained with 0.5 mg/ml of protamine. The trypsin-activated phosphodiesterase has a sedimentation coefficient of 7.8 S corresponding to an approximate molecular weight of 170,000. The 110,000-dalton subunit is much less sensitive to trypsin

  14. Dopamine modulation of rod pathway signaling by suppression of GABAC feedback to rod-driven depolarizing bipolar cells.

    PubMed

    Smith, Benjamin J; Côté, Patrice D; Tremblay, François

    2015-09-01

    Reducing signal gain in the highly sensitive rod pathway prevents saturation as background light levels increase, allowing the dark-adapted retina to encode stimuli over a range of background luminances. Dopamine release is increased during light adaptation and is generally accepted to suppress rod signaling in light-adapted retinas. However, recent research has suggested that dopamine, acting through D1 receptors, could additionally produce a sensitization of the rod pathway in dim light conditions via gamma-aminobutyric acid (GABA) type C receptors. Here, we evaluated the overall activity of the depolarizing bipolar cell (DBC) population in vivo to ensure the integrity of long-distance network interactions by quantifying the b-wave of the electroretinogram in mice. We showed that dopamine, acting through D1 receptors, reduced the amplitude and sensitivity of rod-driven DBCs during light adaptation by suppressing GABA type A receptor-mediated serial inhibition onto rod DBC GABA type C receptors. Block of D1 receptors did not suppress rod-driven DBC sensitivity when GABAA -mediated serial inhibition was blocked by gabazine, suggesting that the reduction in rod-driven DBC sensitivity in the absence of D1 receptors was due to disinhibition of serial inhibitory GABAergic circuitry rather than a direct facilitatory effect on GABA release onto rod-driven DBC GABA type C receptors. Finally, the large population of GABAergic A17 wide-field amacrine cells known to maintain reciprocal inhibition with rod DBCs could be excluded from the proposed disinhibitory circuit after treatment with 5,7-dihydroxytryptamine. PMID:26080286

  15. ALMA 1.3 mm observations of the Fomalhaut System

    NASA Astrophysics Data System (ADS)

    White, Jacob; Boley, Aaron C.; Ford, Eric B.; Payne, Matthew John; Dent, William; Corder, Stuartt

    2016-10-01

    We present ALMA Band 6 (1.3 mm) observations of Fomalhaut and its debris disk. Since the system is relatively close at 7.7 pc, it has been the target of numerous studies at multiple wavelengths, and can serve as a testbed for debris disk evolution models and planet-disk interactions. Outstanding issues that need to be resolved to properly characterize the debris include tightening constraints on the spectral index in the submm/mm regime and determining whether there is indeed excess over the stellar emission, indicating the presence of an inner debris disk or ring.These ALMA 1.3 mm observations provide the highest resolution observations to date of the mm grains the outer ring. Tight constraints are placed on the geometry of the disk and on the mm-wavelength spectral index. We explore fitting the debris disk model in the image plane in addition to the standard method of fitting the visibilities. The results are compared and potential advantages/disadvantages of each approach are discussed.The central emission detected is indistinguishable from a point source, with 0.89 mJy being the best fit flux of the host star for Fomalhaut itself. This implies that any inner debris component must contribute little to the total central emission. Moreover, the stellar flux is less than 70% of that predicted by extrapolating a blackbody from the constrained photosphere temperature and just over 70% of the flux if extrapolating from the far infrared. This behavior is similar to that seen in the Sun for submm/mm wavelengths, but even more pronounced. Currently, insufficient data exists to properly constrain the degree to which stellar atmospheres affect the observed flux in the submm/mm regime. This result is part of an ongoing larger project focused on measuring the emission from stellar atmospheres at submm/mm wavelengths, which directly impacts inferred excesses for debris disk studies.

  16. [Degradation of oil derivatives by Acinetobacter calcoaceticus MM5].

    PubMed

    Marín, M M; Ortiz, M L; Laborda, F

    1994-01-01

    This paper describes the isolation of microorganisms from polluted heating oil. The growth of one of them has been studied (Acinetobacter calcoaceticus MM5) in several linear and branched hydrocarbons as well as the effect of its growth on commercial diesel oil. Acinetobacter calcoaceticus MM5 is not capable of using glucose as its only source of carbon, and it needs the presence of nitrogen and phosphorus sources to degrade any petroleum by-product.

  17. Design and Performance Evaluation of a Linear Ion Trap Mass Analyzer Featuring Half Round Rod Electrodes

    NASA Astrophysics Data System (ADS)

    Li, Xiaoxu; Zhang, Xiaohua; Yao, Rujiao; He, Yang; Zhu, Yongyong; Qian, Jie

    2015-05-01

    A novel linear ion trap mass analyzer featuring half round rod electrodes (HreLIT) has been built. It is mainly composed of two pairs of stainless steel electrodes which have a cross-section of half round rod and a pair of end electrodes. The HreLIT has a simple structure and so it could be assembled by hand with relatively high mechanical accuracy. The external dimension of HreLIT is 50 mm × 29.5 mm × 28 mm (length × width × height) and its internal volume is about 3.8 cm3. A home-made HreLIT mass spectrometer with three-stage vacuum system was built and the performance of HreLIT was characterized using reserpine solution and PPG standard solution. When the scan rate was 254 u/s, mass peak with FWHM of 0.14 u was achieved for ions with m/z 609, which corresponds to a mass resolution of 4350. The HreLIT was also operated at a low q value of 0.28 to extend its mass range. The experiment result showed a mass range of over 2800 u and the amplitude of radio frequency (rf) signal was only 1560 V (0-p). Three-stage tandem mass spectrometry was successfully performed in the HreLIT, and the collision-induced dissociation (CID) efficiencies of MS2 (CID of ions with m/z 609) and MS3 (CID of ions with m/z 448) were 78% and 59%, respectively.

  18. Magnetic properties of Nd 55- xCo xFe 30Al 10B 5 cast rods

    NASA Astrophysics Data System (ADS)

    Dan, N. H.; Phuc, N. X.; Hong, L. V.; Kong, H. Z.; Ding, J.

    2003-04-01

    Nd 55- xCo xFe 30Al 10B 5 ( x=0,5,10,15 and 20) rods with a thickness of 1 mm were prepared by the arc-melting copper mold suction-casting method. At appropriate compositions, the coercivity, remanence and Curie temperature of the alloys simultaneously rise considerably. Coercivities larger than 1120 kA/m have been observed at room temperature for rods with x-values between 10 and 20. The remanent magnetization rises from ∼13 to ∼24 A m 2/kg and the Curie temperature increases from ∼450 to ∼625 K when the Co-concentration, x, in the alloys increases from 0 to 20. The magnetic behavior of the alloys has been investigated at low temperatures.

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

    PubMed

    Meerwaldt, J D; Schmitz, P I

    1988-09-15

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

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

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

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

  1. Dynamics of rod eutectic growth patterns in confined geometry

    NASA Astrophysics Data System (ADS)

    Şerefoǧlu, Melis; Bottin-Rousseau, S.; Akamatsu, S.; Faivre, G.

    2012-01-01

    The dynamics of rod-like eutectics are examined using a directional solidification setup, which allows real-time observation of the whole solidification front in specimens of transparent eutectic alloys -here, succinonitrile-(D)camphor. In steady-state, rod eutectic growth patterns consist of triangular arrays, more or less disturbed by topological defects. In the absence of strong convection and of crystallographic anisotropy, the long-time evolution of the pattern is dominated by "imperfections" of the system, such as misalignment of the temperature gradient, and finite-size. In this study, we present experimental results on the finite-size effects on rod eutectics and show that a rod to lamella transition takes place as a result of finite-size effect only, at a given alloy concentration.

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

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

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

  3. Ribbon rod for use in oil well apparatus

    SciTech Connect

    Tanner, C.J.; Bender, R.E.; Simson, A.K.; McCutchen, H. Jr.

    1986-01-07

    This patent describes a ribbon rod for use in oil well tubing as a replacement for a conventional steel sucker rod. The ribbon rod consists of: an elongated ribbon having a core of relatively stiff material that still has a degree of flexibility such that the ribbon is capable of being wound onto and dispensed from a rotatable reel and can support the weight of oil pumping apparatus attached to a downhole portion of the ribbon, the ribbon core having opposed side surfaces and relatively narrow end surfaces joining the side surfaces; a ply of fabric overlying the side surfaces to provide transverse strength to the ribbon rod; and corner tows extending over the end surfaces to provide damage resistance to the ribbon as it is raised and lowered in the oil well tubing.

  4. Physics analysis of the gang partial rod drive event

    SciTech Connect

    Boman, C.; Frost, R.L.

    1992-08-01

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  10. Efficiency of Hysteresis Rods in Small Spacecraft Attitude Stabilization

    PubMed Central

    Farrahi, Assal; Sanz-Andrés, Ángel

    2013-01-01

    A semiempirical method for predicting the damping efficiency of hysteresis rods on-board small satellites is presented. It is based on the evaluation of dissipating energy variation of different ferromagnetic materials for two different rod shapes: thin film and circular cross-section rods, as a function of their elongation. Based on this formulation, an optimum design considering the size of hysteresis rods, their cross section shape, and layout has been proposed. Finally, the formulation developed was applied to the case of four existing small satellites, whose corresponding in-flight data are published. A good agreement between the estimated rotational speed decay time and the in-flight data has been observed. PMID:24501579

  11. 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.

  12. Damage mechanisms in uniaxial compression of single enamel rods.

    PubMed

    An, Bingbing; Wang, Raorao; Arola, Dwayne; Zhang, Dongsheng

    2015-02-01

    Enamel possesses a complex hierarchical structure, which bestows this tissue with unique mechanical properties. In this study, the mechanical behavior of single enamel rods was investigated under uniaxial compression. Numerical simulations were also performed using micromechanics models for individual enamel rods to identify the damage mechanisms contributing to the constitutive behavior. Experimental results showed that the single rods exhibited an elastic modulus ranging from 10~31 GPa, and that they undergo post-yield strain-hardening. The primary damage mode consisted of delamination within the assembly of mineral crystals. Results from numerical simulations suggest that strain localization within individual rods is responsible for the observed delamination, which is believed to arise from the non-uniform arrangement of mineral crystals. This mechanism was independent of mineral morphology and properties. The non-uniform crystal arrangement results in friction between crystals with different inclination angles and is believed to be responsible for the post-yield strain hardening behavior. PMID:25460920

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

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

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

  14. Bead-rod-spring models in random flows.

    PubMed

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

    2016-08-01

    Bead-rod-spring models are the foundation of the kinetic theory of polymer solutions. We derive the diffusion equation for the probability density function of the configuration of a general bead-rod-spring model in short-correlated Gaussian random flows. Under isotropic conditions, we solve this equation analytically for the elastic rhombus model introduced by Curtiss, Bird, and Hassager [Adv. Chem. Phys. 35, 31 (1976)]. PMID:27627227

  15. Double-clad nuclear-fuel safety rod

    DOEpatents

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

    1981-12-30

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

  16. Apparatus for injection casting metallic nuclear energy fuel rods

    SciTech Connect

    Seidel, B.R.; Tracy, D.B.; Griffiths, V.

    1991-09-03

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

  17. Apparatus for injection casting metallic nuclear energy fuel rods

    SciTech Connect

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

    1991-01-01

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

  18. Hand-held computer designs rod pumping installation

    SciTech Connect

    Herlihy, J.D.

    1984-10-01

    This article describes the program designed to facilitate the design of sucker rod pumping systems for conventional and Mark 2 units. For depths of 2000' or less the modified Mill's method is used, and below 2000' the design procedures of API RP llL are incorporated. The program automatically uses the appropriate design procedure depending on the fluid or pump level. The pump depth is used to calculate rod weighs and the working fluid level to calculate net lift considerations.

  19. Experimental study of burnout in channels with twisted fuel rods

    NASA Astrophysics Data System (ADS)

    Bol'Shakov, V. V.; Bashkirtsev, S. M.; Kobzar', L. L.; Morozov, A. G.

    2007-05-01

    The results of experimental studies of pressure drop and critical heat flux in the models of fuel assemblies (FAs) with fuel rod simulators twisted relative to the longitudinal axis and a three-ray cross section are considered. The experimental data are compared to the results obtained with the use of techniques adopted for design calculations with fuel rod bundles of type-VVER reactors.

  20. BWR fuel rod performance evaluation program. Final report

    SciTech Connect

    Rowland, T.C.

    1986-05-01

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

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

    SciTech Connect

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

    1990-01-01

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

  2. Bead-rod-spring models in random flows

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  3. Percolation thresholds for rod-like particles: polydispersity effects

    NASA Astrophysics Data System (ADS)

    Chatterjee, Avik P.

    2008-06-01

    A model based upon excluded volume considerations is presented for the connectedness percolation thresholds in polydisperse systems of cylindrical rod-like nanoparticles. The dependence of the percolation threshold upon polydispersity index and number-averaged aspect ratio is examined for two different distribution functions for the rod radii and lengths. The importance of accounting for polydispersity is explored in the context of measurements of the elastic moduli and electrical conductance in fibre-filled nanocomposites.

  4. Structure for an LHC 90mm Nb3Sn Quadrupole Magnet

    SciTech Connect

    Hafalia, A.R.; Caspi, S.; Bartlett, S.E.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hannaford, C.R.; Higley, H.; Lietzke, A.F.; Lau, B.; Liggins, N.; Mattafirri, S.; McInturff, A.D.; Nyman, M.; Sabbi,G.L.; Scanlan, R.M.; Swanson, J.

    2005-04-16

    A full-scale mechanical model of the LHC Nb{sub 3}Sn quadrupole magnet structure has been designed, built and tested. The structure will support a 90mm bore, 1m long magnet prototype as part of the US LHC Accelerator Research Program (LARP). The structure utilizes Bladder and Key Technology to control and transfer pre-stress from an outer aluminum shell to an inner coil. Axial aluminum rods take care of pre-stress at the ends--ensuring that the coil is fully constrained along all three axes. The outer aluminum shell and an inner ''dummy coil'' (aluminum tube) were extensively instrumented with strain gauges. The gauges were used to monitor and map the effectiveness of the stress relation between the loading structure and a ''dummy'' coil through varying mechanical load conditions --from bladder and key pre-stress at room temperature through cool-down. Test results of the stress distribution in the structure and the in dummy coil is reported and compared with expected results calculated with the structural analysis program ANSYS.

  5. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... case of products blended with some portion of biomass-based fuel, the carbon share in Table MM-1 of... biomass should not be reported, but products that were derived from both biomass and a petroleum...

  6. Stuffing box for a sucker rod pump assembly

    SciTech Connect

    Johnson, M.B.

    1987-03-03

    A stuffing box is described for use with a sucker rod pump assembly for a producing well including a polish rod at the upper end of the sucker rods, comprising a tubular housing for mounting on the wellhead of a producing well through which the polish rod reciprocates. Two longitudinally spaced packing assemblies are located in the tubular housing in sealing engagement with the polish rod and the housing to provide an annular chamber for a lubricating fluid to surround the polish rod. The box also comprises a lubricating fluid reservoir mounted on the tubular housing and surrounding the portion of the housing in which the annular chamber is located, upper and lower ports in the housing adjacent the upper and lower ends of the chamber connecting the annular chamber with the lubricating fluid reservoir, the housing being imperforate between the ports, and a removable annular spacer located in the annular chamber between the packing assemblies to hold the packing assemblies spaced apart. The spacer has upper and lower ports adjacent the upper and lower end of the chamber and is in substantially the same plane as the upper and lower ports in the housing.

  7. 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.

  8. Experimental and computational studies of rod-deployment mechanisms

    SciTech Connect

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

    1996-08-01

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

  9. Evaluation of ceramic packed-rod regenerator matrices

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  10. A Statistical Approach to Predict the Failure Enthalpy and Reliability of Irradiated PWR Fuel Rods During Reactivity-Initiated Accidents

    SciTech Connect

    Nam, Cheol; Jeong, Yong-Hwan; Jung, Youn-Ho

    2001-11-15

    During the last decade, the failure behavior of high-burnup fuel rods under a reactivity-initiated accident (RIA) condition has been a serious concern since fuel rod failures at low enthalpy have been observed. This has resulted in the reassessment of existing licensing criteria and failure-mode study. To address the issue, a statistics-based methodology is suggested to predict failure probability of irradiated fuel rods under an RIA. Based on RIA simulation results in the literature, a failure enthalpy correlation for an irradiated fuel rod is constructed as a function of oxide thickness, fuel burnup, and pulse width. Using the failure enthalpy correlation, a new concept of ''equivalent enthalpy'' is introduced to reflect the effects of the three primary factors as well as peak fuel enthalpy into a single damage parameter. Moreover, the failure distribution function with equivalent enthalpy is derived, applying a two-parameter Weibull statistical model. Finally, the sensitivity analysis is carried out to estimate the effects of burnup, corrosion, peak fuel enthalpy, pulse width, and cladding materials used.

  11. Investigation of the Rate Dependence of Long-Rod Penetration of Granular Media Using AN Improved Dsr Algorithm

    NASA Astrophysics Data System (ADS)

    Addiss, John W.; Collins, Adam L.; Proud, William G.

    2009-12-01

    Digital Speckle Radiography (DSR), a technique allowing measurement of the full field displacement maps in a plane within an opaque material, is used to follow the temporal progression of a long-rod (100 mm long, 10 mm diameter) penetrating a granular sample at a variety of rates. Quasi-static rates of 1.5 mm/min are achieved using an Instron machine, 5 m/s is achieved using a drop-weight and velocities between 10 and 200 m/s are achieved using a light gas gun. These experiments are carried out using a series of time delayed flash x-ray images analysed with an optimised Digital Image Cross Correlation algorithm (DICC). The subsequent data sheds considerable light on the response of granular materials to penetration at a variety of rates. Particularly, a large difference in the response of the material between quasi-static and dynamic rates is observed.

  12. INVESTIGATION OF THE RATE DEPENDENCE OF LONG-ROD PENETRATION OF GRANULAR MEDIA USING AN IMPROVED DSR ALGORITHM

    SciTech Connect

    Addiss, John W.; Collins, Adam L.; Proud, William G.

    2009-12-28

    Digital Speckle Radiography (DSR), a technique allowing measurement of the full field displacement maps in a plane within an opaque material, is used to follow the temporal progression of a long-rod (100 mm long, 10 mm diameter) penetrating a granular sample at a variety of rates. Quasi-static rates of 1.5 mm/min are achieved using an Instron machine, 5 m/s is achieved using a drop-weight and velocities between 10 and 200 m/s are achieved using a light gas gun. These experiments are carried out using a series of time delayed flash x-ray images analysed with an optimised Digital Image Cross Correlation algorithm (DICC). The subsequent data sheds considerable light on the response of granular materials to penetration at a variety of rates. Particularly, a large difference in the response of the material between quasi-static and dynamic rates is observed.

  13. 49 CFR 230.96 - Main, side, and valve motion rods.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Locomotives and Tenders Driving Gear § 230.96 Main, side, and valve motion rods. (a) General. Main, side or... defective main rods, side rods, and valve gear components. (c) Bearings and bushings. Bearings and bushings.... The total amount of side motion of each rod on its crank pin shall not exceed 1/4 inch. (e) Oil...

  14. 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.

  15. 78 FR 12718 - Certain Steel Threaded Rod From the People's Republic of China: Affirmative Final Determination...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

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

  16. 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

  17. CMOS mm-wave transceivers for Gbps wireless communication

    NASA Astrophysics Data System (ADS)

    Baoyong, Chi; Zheng, Song; Lixue, Kuang; Haikun, Jia; Xiangyu, Meng; Zhihua, Wang

    2016-07-01

    The challenges in the design of CMOS millimeter-wave (mm-wave) transceiver for Gbps wireless communication are discussed. To support the Gbps data rate, the link bandwidth of the receiver/transmitter must be wide enough, which puts a lot of pressure on the mm-wave front-end as well as on the baseband circuit. This paper discusses the effects of the limited link bandwidth on the transceiver system performance and overviews the bandwidth expansion techniques for mm-wave amplifiers and IF programmable gain amplifier. Furthermore, dual-mode power amplifier (PA) and self-healing technique are introduced to improve the PA's average efficiency and to deal with the process, voltage, and temperature variation issue, respectively. Several fully-integrated CMOS mm-wave transceivers are also presented to give a short overview on the state-of-the-art mm-wave transceivers. Project supported in part by the National Natural Science Foundation of China (No. 61331003).

  18. Cost-effective methods for designing and operating fiberglass sucker rod strings

    SciTech Connect

    Jacobs, G.H.

    1986-01-01

    This paper describes procedures used by Amoco Production Company in a West Texas district to maximize the life of more than 200 fiberglass rod strings in service at depths between 5000 and 8000 ft. The paper describes rod string design methods, operating practices, and failure analyses for two major manufacturers' rods. Emphasis has been placed on showing procedures used in designing fiberglass rod strings for cost effective installation and for operating so as to minimize the number of rod string failures and, consequently, rod string operating costs. Actual cases histories are used to illustrate the reduction in failure frequency which results from proper rod string design, operating practices, and failure analysis.

  19. Assembly and Test of HD2, a 36 mm bore high field Nb3Sn Dipole Magnet

    SciTech Connect

    Ferracin, P.; Bingham, B.; Caspi, S.; Cheng, D. W,.; Dietderich, D. R.; Felice, H.; Godeke, A.; Hafalia, A. R.; Hannaford, C. R.; Joseph, J.; Lietzke, A. F.; Lizarazo, J.; Sabbi, G.; Trillaud, F.; Wang, X.

    2008-08-17

    We report on the fabrication, assembly, and test of the Nb{sub 3}Sn dipole magnet HD2. The magnet, aimed at demonstrating the application of Nb{sub 3}Sn superconductor in high field accelerator-type dipoles, features a 36 mm clear bore surrounded by block-type coils with tilted ends. The coil design is optimized to minimize geometric harmonics in the aperture and the magnetic peak field on the conductor in the coil ends. The target bore field of 15 T at 4.3 K is consistent with critical current measurements of extracted strands. The coils are horizontally pre-stressed during assembly using an external aluminum shell pre-tensioned with water-pressurized bladders. Axial pre-loading of the coil ends is accomplished through two end plates and four aluminum tension rods. The strain in coil, shell, and rods is monitored with strain gauges during assembly, cool-down and magnet excitation, and compared with 3D finite element computations. Magnet's training performance, quench locations, and ramp-rate dependence are then analyzed and discussed.

  20. High quality draft genome sequence of Leucobacter chironomi strain MM2LBT (DSM 19883T) isolated from a Chironomus sp. egg mass

    PubMed Central

    2015-01-01

    Leucobacter chironomi strain MM2LBT (Halpern et al., Int J Syst Evol Microbiol 59:665-70 2009) is a Gram-positive, rod shaped, non-motile, aerobic, chemoorganotroph bacterium. L. chironomi belongs to the family Microbacteriaceae, a family within the class Actinobacteria. Strain MM2LBT was isolated from a chironomid (Diptera; Chironomidae) egg mass that was sampled from a waste stabilization pond in northern Israel. In a phylogenetic tree based on 16S rRNA gene sequences, strain MM2LBT formed a distinct branch within the radiation encompassing the genus Leucobacter. Here we describe the features of this organism, together with the complete genome sequence and annotation. The DNA GC content is 69.90%. The chromosome length is 2,964,712 bp. It encodes 2,690 proteins and 61 RNA genes. L. chironomi genome is part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project. PMID:26203333